diff.c

   1 /*
   2  * Copyright (C) 2005 Junio C Hamano
   3  */
   4 #include "cache.h"
   5 #include "quote.h"
   6 #include "diff.h"
   7 #include "diffcore.h"
   8 #include "delta.h"
   9 #include "xdiff-interface.h"
  10 #include "color.h"
  11 #include "attr.h"
  12 #include "run-command.h"
  13 #include "utf8.h"
  14 #include "userdiff.h"
  15 #include "sigchain.h"
  16 #include "submodule.h"
  17 #include "ll-merge.h"
  18 #include "string-list.h"
  19
  20 #ifdef NO_FAST_WORKING_DIRECTORY
  21 #define FAST_WORKING_DIRECTORY 0
  22 #else
  23 #define FAST_WORKING_DIRECTORY 1
  24 #endif
  25
  26 static int diff_detect_rename_default;
  27 static int diff_rename_limit_default = 400;
  28 static int diff_suppress_blank_empty;
  29 static int diff_use_color_default = -1;
  30 static int diff_context_default = 3;
  31 static const char *diff_word_regex_cfg;
  32 static const char *external_diff_cmd_cfg;
  33 int diff_auto_refresh_index = 1;
  34 static int diff_mnemonic_prefix;
  35 static int diff_no_prefix;
  36 static int diff_stat_graph_width;
  37 static int diff_dirstat_permille_default = 30;
  38 static struct diff_options default_diff_options;
  39
  40 static char diff_colors[][COLOR_MAXLEN] = {
  41         GIT_COLOR_RESET,
  42         GIT_COLOR_NORMAL,       /* PLAIN */
  43         GIT_COLOR_BOLD,         /* METAINFO */
  44         GIT_COLOR_CYAN,         /* FRAGINFO */
  45         GIT_COLOR_RED,          /* OLD */
  46         GIT_COLOR_GREEN,        /* NEW */
  47         GIT_COLOR_YELLOW,       /* COMMIT */
  48         GIT_COLOR_BG_RED,       /* WHITESPACE */
  49         GIT_COLOR_NORMAL,       /* FUNCINFO */
  50 };
  51
  52 static int parse_diff_color_slot(const char *var, int ofs)
  53 {
  54         if (!strcasecmp(var+ofs, "plain"))
  55                 return DIFF_PLAIN;
  56         if (!strcasecmp(var+ofs, "meta"))
  57                 return DIFF_METAINFO;
  58         if (!strcasecmp(var+ofs, "frag"))
  59                 return DIFF_FRAGINFO;
  60         if (!strcasecmp(var+ofs, "old"))
  61                 return DIFF_FILE_OLD;
  62         if (!strcasecmp(var+ofs, "new"))
  63                 return DIFF_FILE_NEW;
  64         if (!strcasecmp(var+ofs, "commit"))
  65                 return DIFF_COMMIT;
  66         if (!strcasecmp(var+ofs, "whitespace"))
  67                 return DIFF_WHITESPACE;
  68         if (!strcasecmp(var+ofs, "func"))
  69                 return DIFF_FUNCINFO;
  70         return -1;
  71 }
  72
  73 static int parse_dirstat_params(struct diff_options *options, const char *params_string,
  74                                 struct strbuf *errmsg)
  75 {
  76         char *params_copy = xstrdup(params_string);
  77         struct string_list params = STRING_LIST_INIT_NODUP;
  78         int ret = 0;
  79         int i;
  80
  81         if (*params_copy)
  82                 string_list_split_in_place(&params, params_copy, ',', -1);
  83         for (i = 0; i < params.nr; i++) {
  84                 const char *p = params.items[i].string;
  85                 if (!strcmp(p, "changes")) {
  86                         DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  87                         DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  88                 } else if (!strcmp(p, "lines")) {
  89                         DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
  90                         DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  91                 } else if (!strcmp(p, "files")) {
  92                         DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  93                         DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
  94                 } else if (!strcmp(p, "noncumulative")) {
  95                         DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
  96                 } else if (!strcmp(p, "cumulative")) {
  97                         DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
  98                 } else if (isdigit(*p)) {
  99                         char *end;
 100                         int permille = strtoul(p, &end, 10) * 10;
 101                         if (*end == '.' && isdigit(*++end)) {
 102                                 /* only use first digit */
 103                                 permille += *end - '0';
 104                                 /* .. and ignore any further digits */
 105                                 while (isdigit(*++end))
 106                                         ; /* nothing */
 107                         }
 108                         if (!*end)
 109                                 options->dirstat_permille = permille;
 110                         else {
 111                                 strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 112                                             p);
 113                                 ret++;
 114                         }
 115                 } else {
 116                         strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 117                         ret++;
 118                 }
 119
 120         }
 121         string_list_clear(&params, 0);
 122         free(params_copy);
 123         return ret;
 124 }
 125
 126 static int parse_submodule_params(struct diff_options *options, const char *value)
 127 {
 128         if (!strcmp(value, "log"))
 129                 DIFF_OPT_SET(options, SUBMODULE_LOG);
 130         else if (!strcmp(value, "short"))
 131                 DIFF_OPT_CLR(options, SUBMODULE_LOG);
 132         else
 133                 return -1;
 134         return 0;
 135 }
 136
 137 static int git_config_rename(const char *var, const char *value)
 138 {
 139         if (!value)
 140                 return DIFF_DETECT_RENAME;
 141         if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 142                 return  DIFF_DETECT_COPY;
 143         return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 144 }
 145
 146 /*
 147  * These are to give UI layer defaults.
 148  * The core-level commands such as git-diff-files should
 149  * never be affected by the setting of diff.renames
 150  * the user happens to have in the configuration file.
 151  */
 152 int git_diff_ui_config(const char *var, const char *value, void *cb)
 153 {
 154         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 155                 diff_use_color_default = git_config_colorbool(var, value);
 156                 return 0;
 157         }
 158         if (!strcmp(var, "diff.context")) {
 159                 diff_context_default = git_config_int(var, value);
 160                 if (diff_context_default < 0)
 161                         return -1;
 162                 return 0;
 163         }
 164         if (!strcmp(var, "diff.renames")) {
 165                 diff_detect_rename_default = git_config_rename(var, value);
 166                 return 0;
 167         }
 168         if (!strcmp(var, "diff.autorefreshindex")) {
 169                 diff_auto_refresh_index = git_config_bool(var, value);
 170                 return 0;
 171         }
 172         if (!strcmp(var, "diff.mnemonicprefix")) {
 173                 diff_mnemonic_prefix = git_config_bool(var, value);
 174                 return 0;
 175         }
 176         if (!strcmp(var, "diff.noprefix")) {
 177                 diff_no_prefix = git_config_bool(var, value);
 178                 return 0;
 179         }
 180         if (!strcmp(var, "diff.statgraphwidth")) {
 181                 diff_stat_graph_width = git_config_int(var, value);
 182                 return 0;
 183         }
 184         if (!strcmp(var, "diff.external"))
 185                 return git_config_string(&external_diff_cmd_cfg, var, value);
 186         if (!strcmp(var, "diff.wordregex"))
 187                 return git_config_string(&diff_word_regex_cfg, var, value);
 188
 189         if (!strcmp(var, "diff.ignoresubmodules"))
 190                 handle_ignore_submodules_arg(&default_diff_options, value);
 191
 192         if (!strcmp(var, "diff.submodule")) {
 193                 if (parse_submodule_params(&default_diff_options, value))
 194                         warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 195                                 value);
 196                 return 0;
 197         }
 198
 199         if (git_color_config(var, value, cb) < 0)
 200                 return -1;
 201
 202         return git_diff_basic_config(var, value, cb);
 203 }
 204
 205 int git_diff_basic_config(const char *var, const char *value, void *cb)
 206 {
 207         if (!strcmp(var, "diff.renamelimit")) {
 208                 diff_rename_limit_default = git_config_int(var, value);
 209                 return 0;
 210         }
 211
 212         if (userdiff_config(var, value) < 0)
 213                 return -1;
 214
 215         if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
 216                 int slot = parse_diff_color_slot(var, 11);
 217                 if (slot < 0)
 218                         return 0;
 219                 if (!value)
 220                         return config_error_nonbool(var);
 221                 color_parse(value, var, diff_colors[slot]);
 222                 return 0;
 223         }
 224
 225         /* like GNU diff's --suppress-blank-empty option  */
 226         if (!strcmp(var, "diff.suppressblankempty") ||
 227                         /* for backwards compatibility */
 228                         !strcmp(var, "diff.suppress-blank-empty")) {
 229                 diff_suppress_blank_empty = git_config_bool(var, value);
 230                 return 0;
 231         }
 232
 233         if (!strcmp(var, "diff.dirstat")) {
 234                 struct strbuf errmsg = STRBUF_INIT;
 235                 default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 236                 if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 237                         warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 238                                 errmsg.buf);
 239                 strbuf_release(&errmsg);
 240                 diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 241                 return 0;
 242         }
 243
 244         if (!prefixcmp(var, "submodule."))
 245                 return parse_submodule_config_option(var, value);
 246
 247         return git_default_config(var, value, cb);
 248 }
 249
 250 static char *quote_two(const char *one, const char *two)
 251 {
 252         int need_one = quote_c_style(one, NULL, NULL, 1);
 253         int need_two = quote_c_style(two, NULL, NULL, 1);
 254         struct strbuf res = STRBUF_INIT;
 255
 256         if (need_one + need_two) {
 257                 strbuf_addch(&res, '"');
 258                 quote_c_style(one, &res, NULL, 1);
 259                 quote_c_style(two, &res, NULL, 1);
 260                 strbuf_addch(&res, '"');
 261         } else {
 262                 strbuf_addstr(&res, one);
 263                 strbuf_addstr(&res, two);
 264         }
 265         return strbuf_detach(&res, NULL);
 266 }
 267
 268 static const char *external_diff(void)
 269 {
 270         static const char *external_diff_cmd = NULL;
 271         static int done_preparing = 0;
 272
 273         if (done_preparing)
 274                 return external_diff_cmd;
 275         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 276         if (!external_diff_cmd)
 277                 external_diff_cmd = external_diff_cmd_cfg;
 278         done_preparing = 1;
 279         return external_diff_cmd;
 280 }
 281
 282 static struct diff_tempfile {
 283         const char *name; /* filename external diff should read from */
 284         char hex[41];
 285         char mode[10];
 286         char tmp_path[PATH_MAX];
 287 } diff_temp[2];
 288
 289 typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 290
 291 struct emit_callback {
 292         int color_diff;
 293         unsigned ws_rule;
 294         int blank_at_eof_in_preimage;
 295         int blank_at_eof_in_postimage;
 296         int lno_in_preimage;
 297         int lno_in_postimage;
 298         sane_truncate_fn truncate;
 299         const char **label_path;
 300         struct diff_words_data *diff_words;
 301         struct diff_options *opt;
 302         int *found_changesp;
 303         struct strbuf *header;
 304 };
 305
 306 static int count_lines(const char *data, int size)
 307 {
 308         int count, ch, completely_empty = 1, nl_just_seen = 0;
 309         count = 0;
 310         while (0 < size--) {
 311                 ch = *data++;
 312                 if (ch == '\n') {
 313                         count++;
 314                         nl_just_seen = 1;
 315                         completely_empty = 0;
 316                 }
 317                 else {
 318                         nl_just_seen = 0;
 319                         completely_empty = 0;
 320                 }
 321         }
 322         if (completely_empty)
 323                 return 0;
 324         if (!nl_just_seen)
 325                 count++; /* no trailing newline */
 326         return count;
 327 }
 328
 329 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 330 {
 331         if (!DIFF_FILE_VALID(one)) {
 332                 mf->ptr = (char *)""; /* does not matter */
 333                 mf->size = 0;
 334                 return 0;
 335         }
 336         else if (diff_populate_filespec(one, 0))
 337                 return -1;
 338
 339         mf->ptr = one->data;
 340         mf->size = one->size;
 341         return 0;
 342 }
 343
 344 /* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 345 static unsigned long diff_filespec_size(struct diff_filespec *one)
 346 {
 347         if (!DIFF_FILE_VALID(one))
 348                 return 0;
 349         diff_populate_filespec(one, 1);
 350         return one->size;
 351 }
 352
 353 static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 354 {
 355         char *ptr = mf->ptr;
 356         long size = mf->size;
 357         int cnt = 0;
 358
 359         if (!size)
 360                 return cnt;
 361         ptr += size - 1; /* pointing at the very end */
 362         if (*ptr != '\n')
 363                 ; /* incomplete line */
 364         else
 365                 ptr--; /* skip the last LF */
 366         while (mf->ptr < ptr) {
 367                 char *prev_eol;
 368                 for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 369                         if (*prev_eol == '\n')
 370                                 break;
 371                 if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 372                         break;
 373                 cnt++;
 374                 ptr = prev_eol - 1;
 375         }
 376         return cnt;
 377 }
 378
 379 static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 380                                struct emit_callback *ecbdata)
 381 {
 382         int l1, l2, at;
 383         unsigned ws_rule = ecbdata->ws_rule;
 384         l1 = count_trailing_blank(mf1, ws_rule);
 385         l2 = count_trailing_blank(mf2, ws_rule);
 386         if (l2 <= l1) {
 387                 ecbdata->blank_at_eof_in_preimage = 0;
 388                 ecbdata->blank_at_eof_in_postimage = 0;
 389                 return;
 390         }
 391         at = count_lines(mf1->ptr, mf1->size);
 392         ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 393
 394         at = count_lines(mf2->ptr, mf2->size);
 395         ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 396 }
 397
 398 static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 399                         int first, const char *line, int len)
 400 {
 401         int has_trailing_newline, has_trailing_carriage_return;
 402         int nofirst;
 403         FILE *file = o->file;
 404
 405         if (o->output_prefix) {
 406                 struct strbuf *msg = NULL;
 407                 msg = o->output_prefix(o, o->output_prefix_data);
 408                 assert(msg);
 409                 fwrite(msg->buf, msg->len, 1, file);
 410         }
 411
 412         if (len == 0) {
 413                 has_trailing_newline = (first == '\n');
 414                 has_trailing_carriage_return = (!has_trailing_newline &&
 415                                                 (first == '\r'));
 416                 nofirst = has_trailing_newline || has_trailing_carriage_return;
 417         } else {
 418                 has_trailing_newline = (len > 0 && line[len-1] == '\n');
 419                 if (has_trailing_newline)
 420                         len--;
 421                 has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 422                 if (has_trailing_carriage_return)
 423                         len--;
 424                 nofirst = 0;
 425         }
 426
 427         if (len || !nofirst) {
 428                 fputs(set, file);
 429                 if (!nofirst)
 430                         fputc(first, file);
 431                 fwrite(line, len, 1, file);
 432                 fputs(reset, file);
 433         }
 434         if (has_trailing_carriage_return)
 435                 fputc('\r', file);
 436         if (has_trailing_newline)
 437                 fputc('\n', file);
 438 }
 439
 440 static void emit_line(struct diff_options *o, const char *set, const char *reset,
 441                       const char *line, int len)
 442 {
 443         emit_line_0(o, set, reset, line[0], line+1, len-1);
 444 }
 445
 446 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 447 {
 448         if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 449               ecbdata->blank_at_eof_in_preimage &&
 450               ecbdata->blank_at_eof_in_postimage &&
 451               ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 452               ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 453                 return 0;
 454         return ws_blank_line(line, len, ecbdata->ws_rule);
 455 }
 456
 457 static void emit_add_line(const char *reset,
 458                           struct emit_callback *ecbdata,
 459                           const char *line, int len)
 460 {
 461         const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 462         const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
 463
 464         if (!*ws)
 465                 emit_line_0(ecbdata->opt, set, reset, '+', line, len);
 466         else if (new_blank_line_at_eof(ecbdata, line, len))
 467                 /* Blank line at EOF - paint '+' as well */
 468                 emit_line_0(ecbdata->opt, ws, reset, '+', line, len);
 469         else {
 470                 /* Emit just the prefix, then the rest. */
 471                 emit_line_0(ecbdata->opt, set, reset, '+', "", 0);
 472                 ws_check_emit(line, len, ecbdata->ws_rule,
 473                               ecbdata->opt->file, set, reset, ws);
 474         }
 475 }
 476
 477 static void emit_hunk_header(struct emit_callback *ecbdata,
 478                              const char *line, int len)
 479 {
 480         const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
 481         const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 482         const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 483         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 484         static const char atat[2] = { '@', '@' };
 485         const char *cp, *ep;
 486         struct strbuf msgbuf = STRBUF_INIT;
 487         int org_len = len;
 488         int i = 1;
 489
 490         /*
 491          * As a hunk header must begin with "@@ -<old>, +<new> @@",
 492          * it always is at least 10 bytes long.
 493          */
 494         if (len < 10 ||
 495             memcmp(line, atat, 2) ||
 496             !(ep = memmem(line + 2, len - 2, atat, 2))) {
 497                 emit_line(ecbdata->opt, plain, reset, line, len);
 498                 return;
 499         }
 500         ep += 2; /* skip over @@ */
 501
 502         /* The hunk header in fraginfo color */
 503         strbuf_add(&msgbuf, frag, strlen(frag));
 504         strbuf_add(&msgbuf, line, ep - line);
 505         strbuf_add(&msgbuf, reset, strlen(reset));
 506
 507         /*
 508          * trailing "\r\n"
 509          */
 510         for ( ; i < 3; i++)
 511                 if (line[len - i] == '\r' || line[len - i] == '\n')
 512                         len--;
 513
 514         /* blank before the func header */
 515         for (cp = ep; ep - line < len; ep++)
 516                 if (*ep != ' ' && *ep != '\t')
 517                         break;
 518         if (ep != cp) {
 519                 strbuf_add(&msgbuf, plain, strlen(plain));
 520                 strbuf_add(&msgbuf, cp, ep - cp);
 521                 strbuf_add(&msgbuf, reset, strlen(reset));
 522         }
 523
 524         if (ep < line + len) {
 525                 strbuf_add(&msgbuf, func, strlen(func));
 526                 strbuf_add(&msgbuf, ep, line + len - ep);
 527                 strbuf_add(&msgbuf, reset, strlen(reset));
 528         }
 529
 530         strbuf_add(&msgbuf, line + len, org_len - len);
 531         emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 532         strbuf_release(&msgbuf);
 533 }
 534
 535 static struct diff_tempfile *claim_diff_tempfile(void) {
 536         int i;
 537         for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 538                 if (!diff_temp[i].name)
 539                         return diff_temp + i;
 540         die("BUG: diff is failing to clean up its tempfiles");
 541 }
 542
 543 static int remove_tempfile_installed;
 544
 545 static void remove_tempfile(void)
 546 {
 547         int i;
 548         for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 549                 if (diff_temp[i].name == diff_temp[i].tmp_path)
 550                         unlink_or_warn(diff_temp[i].name);
 551                 diff_temp[i].name = NULL;
 552         }
 553 }
 554
 555 static void remove_tempfile_on_signal(int signo)
 556 {
 557         remove_tempfile();
 558         sigchain_pop(signo);
 559         raise(signo);
 560 }
 561
 562 static void print_line_count(FILE *file, int count)
 563 {
 564         switch (count) {
 565         case 0:
 566                 fprintf(file, "0,0");
 567                 break;
 568         case 1:
 569                 fprintf(file, "1");
 570                 break;
 571         default:
 572                 fprintf(file, "1,%d", count);
 573                 break;
 574         }
 575 }
 576
 577 static void emit_rewrite_lines(struct emit_callback *ecb,
 578                                int prefix, const char *data, int size)
 579 {
 580         const char *endp = NULL;
 581         static const char *nneof = " No newline at end of file\n";
 582         const char *old = diff_get_color(ecb->color_diff, DIFF_FILE_OLD);
 583         const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 584
 585         while (0 < size) {
 586                 int len;
 587
 588                 endp = memchr(data, '\n', size);
 589                 len = endp ? (endp - data + 1) : size;
 590                 if (prefix != '+') {
 591                         ecb->lno_in_preimage++;
 592                         emit_line_0(ecb->opt, old, reset, '-',
 593                                     data, len);
 594                 } else {
 595                         ecb->lno_in_postimage++;
 596                         emit_add_line(reset, ecb, data, len);
 597                 }
 598                 size -= len;
 599                 data += len;
 600         }
 601         if (!endp) {
 602                 const char *plain = diff_get_color(ecb->color_diff,
 603                                                    DIFF_PLAIN);
 604                 putc('\n', ecb->opt->file);
 605                 emit_line_0(ecb->opt, plain, reset, '\\',
 606                             nneof, strlen(nneof));
 607         }
 608 }
 609
 610 static void emit_rewrite_diff(const char *name_a,
 611                               const char *name_b,
 612                               struct diff_filespec *one,
 613                               struct diff_filespec *two,
 614                               struct userdiff_driver *textconv_one,
 615                               struct userdiff_driver *textconv_two,
 616                               struct diff_options *o)
 617 {
 618         int lc_a, lc_b;
 619         const char *name_a_tab, *name_b_tab;
 620         const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 621         const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 622         const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 623         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 624         const char *a_prefix, *b_prefix;
 625         char *data_one, *data_two;
 626         size_t size_one, size_two;
 627         struct emit_callback ecbdata;
 628         char *line_prefix = "";
 629         struct strbuf *msgbuf;
 630
 631         if (o && o->output_prefix) {
 632                 msgbuf = o->output_prefix(o, o->output_prefix_data);
 633                 line_prefix = msgbuf->buf;
 634         }
 635
 636         if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 637                 a_prefix = o->b_prefix;
 638                 b_prefix = o->a_prefix;
 639         } else {
 640                 a_prefix = o->a_prefix;
 641                 b_prefix = o->b_prefix;
 642         }
 643
 644         name_a += (*name_a == '/');
 645         name_b += (*name_b == '/');
 646         name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 647         name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 648
 649         strbuf_reset(&a_name);
 650         strbuf_reset(&b_name);
 651         quote_two_c_style(&a_name, a_prefix, name_a, 0);
 652         quote_two_c_style(&b_name, b_prefix, name_b, 0);
 653
 654         size_one = fill_textconv(textconv_one, one, &data_one);
 655         size_two = fill_textconv(textconv_two, two, &data_two);
 656
 657         memset(&ecbdata, 0, sizeof(ecbdata));
 658         ecbdata.color_diff = want_color(o->use_color);
 659         ecbdata.found_changesp = &o->found_changes;
 660         ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
 661         ecbdata.opt = o;
 662         if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 663                 mmfile_t mf1, mf2;
 664                 mf1.ptr = (char *)data_one;
 665                 mf2.ptr = (char *)data_two;
 666                 mf1.size = size_one;
 667                 mf2.size = size_two;
 668                 check_blank_at_eof(&mf1, &mf2, &ecbdata);
 669         }
 670         ecbdata.lno_in_preimage = 1;
 671         ecbdata.lno_in_postimage = 1;
 672
 673         lc_a = count_lines(data_one, size_one);
 674         lc_b = count_lines(data_two, size_two);
 675         fprintf(o->file,
 676                 "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 677                 line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 678                 line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 679                 line_prefix, fraginfo);
 680         if (!o->irreversible_delete)
 681                 print_line_count(o->file, lc_a);
 682         else
 683                 fprintf(o->file, "?,?");
 684         fprintf(o->file, " +");
 685         print_line_count(o->file, lc_b);
 686         fprintf(o->file, " @@%s\n", reset);
 687         if (lc_a && !o->irreversible_delete)
 688                 emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 689         if (lc_b)
 690                 emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 691         if (textconv_one)
 692                 free((char *)data_one);
 693         if (textconv_two)
 694                 free((char *)data_two);
 695 }
 696
 697 struct diff_words_buffer {
 698         mmfile_t text;
 699         long alloc;
 700         struct diff_words_orig {
 701                 const char *begin, *end;
 702         } *orig;
 703         int orig_nr, orig_alloc;
 704 };
 705
 706 static void diff_words_append(char *line, unsigned long len,
 707                 struct diff_words_buffer *buffer)
 708 {
 709         ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 710         line++;
 711         len--;
 712         memcpy(buffer->text.ptr + buffer->text.size, line, len);
 713         buffer->text.size += len;
 714         buffer->text.ptr[buffer->text.size] = '\0';
 715 }
 716
 717 struct diff_words_style_elem {
 718         const char *prefix;
 719         const char *suffix;
 720         const char *color; /* NULL; filled in by the setup code if
 721                             * color is enabled */
 722 };
 723
 724 struct diff_words_style {
 725         enum diff_words_type type;
 726         struct diff_words_style_elem new, old, ctx;
 727         const char *newline;
 728 };
 729
 730 static struct diff_words_style diff_words_styles[] = {
 731         { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 732         { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 733         { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 734 };
 735
 736 struct diff_words_data {
 737         struct diff_words_buffer minus, plus;
 738         const char *current_plus;
 739         int last_minus;
 740         struct diff_options *opt;
 741         regex_t *word_regex;
 742         enum diff_words_type type;
 743         struct diff_words_style *style;
 744 };
 745
 746 static int fn_out_diff_words_write_helper(FILE *fp,
 747                                           struct diff_words_style_elem *st_el,
 748                                           const char *newline,
 749                                           size_t count, const char *buf,
 750                                           const char *line_prefix)
 751 {
 752         int print = 0;
 753
 754         while (count) {
 755                 char *p = memchr(buf, '\n', count);
 756                 if (print)
 757                         fputs(line_prefix, fp);
 758                 if (p != buf) {
 759                         if (st_el->color && fputs(st_el->color, fp) < 0)
 760                                 return -1;
 761                         if (fputs(st_el->prefix, fp) < 0 ||
 762                             fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 763                             fputs(st_el->suffix, fp) < 0)
 764                                 return -1;
 765                         if (st_el->color && *st_el->color
 766                             && fputs(GIT_COLOR_RESET, fp) < 0)
 767                                 return -1;
 768                 }
 769                 if (!p)
 770                         return 0;
 771                 if (fputs(newline, fp) < 0)
 772                         return -1;
 773                 count -= p + 1 - buf;
 774                 buf = p + 1;
 775                 print = 1;
 776         }
 777         return 0;
 778 }
 779
 780 /*
 781  * '--color-words' algorithm can be described as:
 782  *
 783  *   1. collect a the minus/plus lines of a diff hunk, divided into
 784  *      minus-lines and plus-lines;
 785  *
 786  *   2. break both minus-lines and plus-lines into words and
 787  *      place them into two mmfile_t with one word for each line;
 788  *
 789  *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 790  *
 791  * And for the common parts of the both file, we output the plus side text.
 792  * diff_words->current_plus is used to trace the current position of the plus file
 793  * which printed. diff_words->last_minus is used to trace the last minus word
 794  * printed.
 795  *
 796  * For '--graph' to work with '--color-words', we need to output the graph prefix
 797  * on each line of color words output. Generally, there are two conditions on
 798  * which we should output the prefix.
 799  *
 800  *   1. diff_words->last_minus == 0 &&
 801  *      diff_words->current_plus == diff_words->plus.text.ptr
 802  *
 803  *      that is: the plus text must start as a new line, and if there is no minus
 804  *      word printed, a graph prefix must be printed.
 805  *
 806  *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 807  *      *(diff_words->current_plus - 1) == '\n'
 808  *
 809  *      that is: a graph prefix must be printed following a '\n'
 810  */
 811 static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 812 {
 813         if ((diff_words->last_minus == 0 &&
 814                 diff_words->current_plus == diff_words->plus.text.ptr) ||
 815                 (diff_words->current_plus > diff_words->plus.text.ptr &&
 816                 *(diff_words->current_plus - 1) == '\n')) {
 817                 return 1;
 818         } else {
 819                 return 0;
 820         }
 821 }
 822
 823 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 824 {
 825         struct diff_words_data *diff_words = priv;
 826         struct diff_words_style *style = diff_words->style;
 827         int minus_first, minus_len, plus_first, plus_len;
 828         const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 829         struct diff_options *opt = diff_words->opt;
 830         struct strbuf *msgbuf;
 831         char *line_prefix = "";
 832
 833         if (line[0] != '@' || parse_hunk_header(line, len,
 834                         &minus_first, &minus_len, &plus_first, &plus_len))
 835                 return;
 836
 837         assert(opt);
 838         if (opt->output_prefix) {
 839                 msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
 840                 line_prefix = msgbuf->buf;
 841         }
 842
 843         /* POSIX requires that first be decremented by one if len == 0... */
 844         if (minus_len) {
 845                 minus_begin = diff_words->minus.orig[minus_first].begin;
 846                 minus_end =
 847                         diff_words->minus.orig[minus_first + minus_len - 1].end;
 848         } else
 849                 minus_begin = minus_end =
 850                         diff_words->minus.orig[minus_first].end;
 851
 852         if (plus_len) {
 853                 plus_begin = diff_words->plus.orig[plus_first].begin;
 854                 plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 855         } else
 856                 plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 857
 858         if (color_words_output_graph_prefix(diff_words)) {
 859                 fputs(line_prefix, diff_words->opt->file);
 860         }
 861         if (diff_words->current_plus != plus_begin) {
 862                 fn_out_diff_words_write_helper(diff_words->opt->file,
 863                                 &style->ctx, style->newline,
 864                                 plus_begin - diff_words->current_plus,
 865                                 diff_words->current_plus, line_prefix);
 866                 if (*(plus_begin - 1) == '\n')
 867                         fputs(line_prefix, diff_words->opt->file);
 868         }
 869         if (minus_begin != minus_end) {
 870                 fn_out_diff_words_write_helper(diff_words->opt->file,
 871                                 &style->old, style->newline,
 872                                 minus_end - minus_begin, minus_begin,
 873                                 line_prefix);
 874         }
 875         if (plus_begin != plus_end) {
 876                 fn_out_diff_words_write_helper(diff_words->opt->file,
 877                                 &style->new, style->newline,
 878                                 plus_end - plus_begin, plus_begin,
 879                                 line_prefix);
 880         }
 881
 882         diff_words->current_plus = plus_end;
 883         diff_words->last_minus = minus_first;
 884 }
 885
 886 /* This function starts looking at *begin, and returns 0 iff a word was found. */
 887 static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
 888                 int *begin, int *end)
 889 {
 890         if (word_regex && *begin < buffer->size) {
 891                 regmatch_t match[1];
 892                 if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
 893                         char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 894                                         '\n', match[0].rm_eo - match[0].rm_so);
 895                         *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 896                         *begin += match[0].rm_so;
 897                         return *begin >= *end;
 898                 }
 899                 return -1;
 900         }
 901
 902         /* find the next word */
 903         while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 904                 (*begin)++;
 905         if (*begin >= buffer->size)
 906                 return -1;
 907
 908         /* find the end of the word */
 909         *end = *begin + 1;
 910         while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 911                 (*end)++;
 912
 913         return 0;
 914 }
 915
 916 /*
 917  * This function splits the words in buffer->text, stores the list with
 918  * newline separator into out, and saves the offsets of the original words
 919  * in buffer->orig.
 920  */
 921 static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 922                 regex_t *word_regex)
 923 {
 924         int i, j;
 925         long alloc = 0;
 926
 927         out->size = 0;
 928         out->ptr = NULL;
 929
 930         /* fake an empty "0th" word */
 931         ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 932         buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 933         buffer->orig_nr = 1;
 934
 935         for (i = 0; i < buffer->text.size; i++) {
 936                 if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
 937                         return;
 938
 939                 /* store original boundaries */
 940                 ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
 941                                 buffer->orig_alloc);
 942                 buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
 943                 buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
 944                 buffer->orig_nr++;
 945
 946                 /* store one word */
 947                 ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
 948                 memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
 949                 out->ptr[out->size + j - i] = '\n';
 950                 out->size += j - i + 1;
 951
 952                 i = j - 1;
 953         }
 954 }
 955
 956 /* this executes the word diff on the accumulated buffers */
 957 static void diff_words_show(struct diff_words_data *diff_words)
 958 {
 959         xpparam_t xpp;
 960         xdemitconf_t xecfg;
 961         mmfile_t minus, plus;
 962         struct diff_words_style *style = diff_words->style;
 963
 964         struct diff_options *opt = diff_words->opt;
 965         struct strbuf *msgbuf;
 966         char *line_prefix = "";
 967
 968         assert(opt);
 969         if (opt->output_prefix) {
 970                 msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
 971                 line_prefix = msgbuf->buf;
 972         }
 973
 974         /* special case: only removal */
 975         if (!diff_words->plus.text.size) {
 976                 fputs(line_prefix, diff_words->opt->file);
 977                 fn_out_diff_words_write_helper(diff_words->opt->file,
 978                         &style->old, style->newline,
 979                         diff_words->minus.text.size,
 980                         diff_words->minus.text.ptr, line_prefix);
 981                 diff_words->minus.text.size = 0;
 982                 return;
 983         }
 984
 985         diff_words->current_plus = diff_words->plus.text.ptr;
 986         diff_words->last_minus = 0;
 987
 988         memset(&xpp, 0, sizeof(xpp));
 989         memset(&xecfg, 0, sizeof(xecfg));
 990         diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
 991         diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
 992         xpp.flags = 0;
 993         /* as only the hunk header will be parsed, we need a 0-context */
 994         xecfg.ctxlen = 0;
 995         xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
 996                       &xpp, &xecfg);
 997         free(minus.ptr);
 998         free(plus.ptr);
 999         if (diff_words->current_plus != diff_words->plus.text.ptr +
1000                         diff_words->plus.text.size) {
1001                 if (color_words_output_graph_prefix(diff_words))
1002                         fputs(line_prefix, diff_words->opt->file);
1003                 fn_out_diff_words_write_helper(diff_words->opt->file,
1004                         &style->ctx, style->newline,
1005                         diff_words->plus.text.ptr + diff_words->plus.text.size
1006                         - diff_words->current_plus, diff_words->current_plus,
1007                         line_prefix);
1008         }
1009         diff_words->minus.text.size = diff_words->plus.text.size = 0;
1010 }
1011
1012 /* In "color-words" mode, show word-diff of words accumulated in the buffer */
1013 static void diff_words_flush(struct emit_callback *ecbdata)
1014 {
1015         if (ecbdata->diff_words->minus.text.size ||
1016             ecbdata->diff_words->plus.text.size)
1017                 diff_words_show(ecbdata->diff_words);
1018 }
1019
1020 static void diff_filespec_load_driver(struct diff_filespec *one)
1021 {
1022         /* Use already-loaded driver */
1023         if (one->driver)
1024                 return;
1025
1026         if (S_ISREG(one->mode))
1027                 one->driver = userdiff_find_by_path(one->path);
1028
1029         /* Fallback to default settings */
1030         if (!one->driver)
1031                 one->driver = userdiff_find_by_name("default");
1032 }
1033
1034 static const char *userdiff_word_regex(struct diff_filespec *one)
1035 {
1036         diff_filespec_load_driver(one);
1037         return one->driver->word_regex;
1038 }
1039
1040 static void init_diff_words_data(struct emit_callback *ecbdata,
1041                                  struct diff_options *orig_opts,
1042                                  struct diff_filespec *one,
1043                                  struct diff_filespec *two)
1044 {
1045         int i;
1046         struct diff_options *o = xmalloc(sizeof(struct diff_options));
1047         memcpy(o, orig_opts, sizeof(struct diff_options));
1048
1049         ecbdata->diff_words =
1050                 xcalloc(1, sizeof(struct diff_words_data));
1051         ecbdata->diff_words->type = o->word_diff;
1052         ecbdata->diff_words->opt = o;
1053         if (!o->word_regex)
1054                 o->word_regex = userdiff_word_regex(one);
1055         if (!o->word_regex)
1056                 o->word_regex = userdiff_word_regex(two);
1057         if (!o->word_regex)
1058                 o->word_regex = diff_word_regex_cfg;
1059         if (o->word_regex) {
1060                 ecbdata->diff_words->word_regex = (regex_t *)
1061                         xmalloc(sizeof(regex_t));
1062                 if (regcomp(ecbdata->diff_words->word_regex,
1063                             o->word_regex,
1064                             REG_EXTENDED | REG_NEWLINE))
1065                         die ("Invalid regular expression: %s",
1066                              o->word_regex);
1067         }
1068         for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1069                 if (o->word_diff == diff_words_styles[i].type) {
1070                         ecbdata->diff_words->style =
1071                                 &diff_words_styles[i];
1072                         break;
1073                 }
1074         }
1075         if (want_color(o->use_color)) {
1076                 struct diff_words_style *st = ecbdata->diff_words->style;
1077                 st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1078                 st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1079                 st->ctx.color = diff_get_color_opt(o, DIFF_PLAIN);
1080         }
1081 }
1082
1083 static void free_diff_words_data(struct emit_callback *ecbdata)
1084 {
1085         if (ecbdata->diff_words) {
1086                 diff_words_flush(ecbdata);
1087                 free (ecbdata->diff_words->opt);
1088                 free (ecbdata->diff_words->minus.text.ptr);
1089                 free (ecbdata->diff_words->minus.orig);
1090                 free (ecbdata->diff_words->plus.text.ptr);
1091                 free (ecbdata->diff_words->plus.orig);
1092                 if (ecbdata->diff_words->word_regex) {
1093                         regfree(ecbdata->diff_words->word_regex);
1094                         free(ecbdata->diff_words->word_regex);
1095                 }
1096                 free(ecbdata->diff_words);
1097                 ecbdata->diff_words = NULL;
1098         }
1099 }
1100
1101 const char *diff_get_color(int diff_use_color, enum color_diff ix)
1102 {
1103         if (want_color(diff_use_color))
1104                 return diff_colors[ix];
1105         return "";
1106 }
1107
1108 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1109 {
1110         const char *cp;
1111         unsigned long allot;
1112         size_t l = len;
1113
1114         if (ecb->truncate)
1115                 return ecb->truncate(line, len);
1116         cp = line;
1117         allot = l;
1118         while (0 < l) {
1119                 (void) utf8_width(&cp, &l);
1120                 if (!cp)
1121                         break; /* truncated in the middle? */
1122         }
1123         return allot - l;
1124 }
1125
1126 static void find_lno(const char *line, struct emit_callback *ecbdata)
1127 {
1128         const char *p;
1129         ecbdata->lno_in_preimage = 0;
1130         ecbdata->lno_in_postimage = 0;
1131         p = strchr(line, '-');
1132         if (!p)
1133                 return; /* cannot happen */
1134         ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1135         p = strchr(p, '+');
1136         if (!p)
1137                 return; /* cannot happen */
1138         ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1139 }
1140
1141 static void fn_out_consume(void *priv, char *line, unsigned long len)
1142 {
1143         struct emit_callback *ecbdata = priv;
1144         const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1145         const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
1146         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1147         struct diff_options *o = ecbdata->opt;
1148         char *line_prefix = "";
1149         struct strbuf *msgbuf;
1150
1151         if (o && o->output_prefix) {
1152                 msgbuf = o->output_prefix(o, o->output_prefix_data);
1153                 line_prefix = msgbuf->buf;
1154         }
1155
1156         if (ecbdata->header) {
1157                 fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
1158                 strbuf_reset(ecbdata->header);
1159                 ecbdata->header = NULL;
1160         }
1161         *(ecbdata->found_changesp) = 1;
1162
1163         if (ecbdata->label_path[0]) {
1164                 const char *name_a_tab, *name_b_tab;
1165
1166                 name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1167                 name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1168
1169                 fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1170                         line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1171                 fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1172                         line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1173                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1174         }
1175
1176         if (diff_suppress_blank_empty
1177             && len == 2 && line[0] == ' ' && line[1] == '\n') {
1178                 line[0] = '\n';
1179                 len = 1;
1180         }
1181
1182         if (line[0] == '@') {
1183                 if (ecbdata->diff_words)
1184                         diff_words_flush(ecbdata);
1185                 len = sane_truncate_line(ecbdata, line, len);
1186                 find_lno(line, ecbdata);
1187                 emit_hunk_header(ecbdata, line, len);
1188                 if (line[len-1] != '\n')
1189                         putc('\n', ecbdata->opt->file);
1190                 return;
1191         }
1192
1193         if (len < 1) {
1194                 emit_line(ecbdata->opt, reset, reset, line, len);
1195                 if (ecbdata->diff_words
1196                     && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1197                         fputs("~\n", ecbdata->opt->file);
1198                 return;
1199         }
1200
1201         if (ecbdata->diff_words) {
1202                 if (line[0] == '-') {
1203                         diff_words_append(line, len,
1204                                           &ecbdata->diff_words->minus);
1205                         return;
1206                 } else if (line[0] == '+') {
1207                         diff_words_append(line, len,
1208                                           &ecbdata->diff_words->plus);
1209                         return;
1210                 } else if (!prefixcmp(line, "\\ ")) {
1211                         /*
1212                          * Eat the "no newline at eof" marker as if we
1213                          * saw a "+" or "-" line with nothing on it,
1214                          * and return without diff_words_flush() to
1215                          * defer processing. If this is the end of
1216                          * preimage, more "+" lines may come after it.
1217                          */
1218                         return;
1219                 }
1220                 diff_words_flush(ecbdata);
1221                 if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1222                         emit_line(ecbdata->opt, plain, reset, line, len);
1223                         fputs("~\n", ecbdata->opt->file);
1224                 } else {
1225                         /*
1226                          * Skip the prefix character, if any.  With
1227                          * diff_suppress_blank_empty, there may be
1228                          * none.
1229                          */
1230                         if (line[0] != '\n') {
1231                               line++;
1232                               len--;
1233                         }
1234                         emit_line(ecbdata->opt, plain, reset, line, len);
1235                 }
1236                 return;
1237         }
1238
1239         if (line[0] != '+') {
1240                 const char *color =
1241                         diff_get_color(ecbdata->color_diff,
1242                                        line[0] == '-' ? DIFF_FILE_OLD : DIFF_PLAIN);
1243                 ecbdata->lno_in_preimage++;
1244                 if (line[0] == ' ')
1245                         ecbdata->lno_in_postimage++;
1246                 emit_line(ecbdata->opt, color, reset, line, len);
1247         } else {
1248                 ecbdata->lno_in_postimage++;
1249                 emit_add_line(reset, ecbdata, line + 1, len - 1);
1250         }
1251 }
1252
1253 static char *pprint_rename(const char *a, const char *b)
1254 {
1255         const char *old = a;
1256         const char *new = b;
1257         struct strbuf name = STRBUF_INIT;
1258         int pfx_length, sfx_length;
1259         int len_a = strlen(a);
1260         int len_b = strlen(b);
1261         int a_midlen, b_midlen;
1262         int qlen_a = quote_c_style(a, NULL, NULL, 0);
1263         int qlen_b = quote_c_style(b, NULL, NULL, 0);
1264
1265         if (qlen_a || qlen_b) {
1266                 quote_c_style(a, &name, NULL, 0);
1267                 strbuf_addstr(&name, " => ");
1268                 quote_c_style(b, &name, NULL, 0);
1269                 return strbuf_detach(&name, NULL);
1270         }
1271
1272         /* Find common prefix */
1273         pfx_length = 0;
1274         while (*old && *new && *old == *new) {
1275                 if (*old == '/')
1276                         pfx_length = old - a + 1;
1277                 old++;
1278                 new++;
1279         }
1280
1281         /* Find common suffix */
1282         old = a + len_a;
1283         new = b + len_b;
1284         sfx_length = 0;
1285         while (a <= old && b <= new && *old == *new) {
1286                 if (*old == '/')
1287                         sfx_length = len_a - (old - a);
1288                 old--;
1289                 new--;
1290         }
1291
1292         /*
1293          * pfx{mid-a => mid-b}sfx
1294          * {pfx-a => pfx-b}sfx
1295          * pfx{sfx-a => sfx-b}
1296          * name-a => name-b
1297          */
1298         a_midlen = len_a - pfx_length - sfx_length;
1299         b_midlen = len_b - pfx_length - sfx_length;
1300         if (a_midlen < 0)
1301                 a_midlen = 0;
1302         if (b_midlen < 0)
1303                 b_midlen = 0;
1304
1305         strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1306         if (pfx_length + sfx_length) {
1307                 strbuf_add(&name, a, pfx_length);
1308                 strbuf_addch(&name, '{');
1309         }
1310         strbuf_add(&name, a + pfx_length, a_midlen);
1311         strbuf_addstr(&name, " => ");
1312         strbuf_add(&name, b + pfx_length, b_midlen);
1313         if (pfx_length + sfx_length) {
1314                 strbuf_addch(&name, '}');
1315                 strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1316         }
1317         return strbuf_detach(&name, NULL);
1318 }
1319
1320 struct diffstat_t {
1321         int nr;
1322         int alloc;
1323         struct diffstat_file {
1324                 char *from_name;
1325                 char *name;
1326                 char *print_name;
1327                 unsigned is_unmerged:1;
1328                 unsigned is_binary:1;
1329                 unsigned is_renamed:1;
1330                 unsigned is_interesting:1;
1331                 uintmax_t added, deleted;
1332         } **files;
1333 };
1334
1335 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1336                                           const char *name_a,
1337                                           const char *name_b)
1338 {
1339         struct diffstat_file *x;
1340         x = xcalloc(sizeof (*x), 1);
1341         if (diffstat->nr == diffstat->alloc) {
1342                 diffstat->alloc = alloc_nr(diffstat->alloc);
1343                 diffstat->files = xrealloc(diffstat->files,
1344                                 diffstat->alloc * sizeof(x));
1345         }
1346         diffstat->files[diffstat->nr++] = x;
1347         if (name_b) {
1348                 x->from_name = xstrdup(name_a);
1349                 x->name = xstrdup(name_b);
1350                 x->is_renamed = 1;
1351         }
1352         else {
1353                 x->from_name = NULL;
1354                 x->name = xstrdup(name_a);
1355         }
1356         return x;
1357 }
1358
1359 static void diffstat_consume(void *priv, char *line, unsigned long len)
1360 {
1361         struct diffstat_t *diffstat = priv;
1362         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1363
1364         if (line[0] == '+')
1365                 x->added++;
1366         else if (line[0] == '-')
1367                 x->deleted++;
1368 }
1369
1370 const char mime_boundary_leader[] = "------------";
1371
1372 static int scale_linear(int it, int width, int max_change)
1373 {
1374         if (!it)
1375                 return 0;
1376         /*
1377          * make sure that at least one '-' or '+' is printed if
1378          * there is any change to this path. The easiest way is to
1379          * scale linearly as if the alloted width is one column shorter
1380          * than it is, and then add 1 to the result.
1381          */
1382         return 1 + (it * (width - 1) / max_change);
1383 }
1384
1385 static void show_name(FILE *file,
1386                       const char *prefix, const char *name, int len)
1387 {
1388         fprintf(file, " %s%-*s |", prefix, len, name);
1389 }
1390
1391 static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1392 {
1393         if (cnt <= 0)
1394                 return;
1395         fprintf(file, "%s", set);
1396         while (cnt--)
1397                 putc(ch, file);
1398         fprintf(file, "%s", reset);
1399 }
1400
1401 static void fill_print_name(struct diffstat_file *file)
1402 {
1403         char *pname;
1404
1405         if (file->print_name)
1406                 return;
1407
1408         if (!file->is_renamed) {
1409                 struct strbuf buf = STRBUF_INIT;
1410                 if (quote_c_style(file->name, &buf, NULL, 0)) {
1411                         pname = strbuf_detach(&buf, NULL);
1412                 } else {
1413                         pname = file->name;
1414                         strbuf_release(&buf);
1415                 }
1416         } else {
1417                 pname = pprint_rename(file->from_name, file->name);
1418         }
1419         file->print_name = pname;
1420 }
1421
1422 int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1423 {
1424         struct strbuf sb = STRBUF_INIT;
1425         int ret;
1426
1427         if (!files) {
1428                 assert(insertions == 0 && deletions == 0);
1429                 return fprintf(fp, "%s\n", " 0 files changed");
1430         }
1431
1432         strbuf_addf(&sb,
1433                     (files == 1) ? " %d file changed" : " %d files changed",
1434                     files);
1435
1436         /*
1437          * For binary diff, the caller may want to print "x files
1438          * changed" with insertions == 0 && deletions == 0.
1439          *
1440          * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1441          * is probably less confusing (i.e skip over "2 files changed
1442          * but nothing about added/removed lines? Is this a bug in Git?").
1443          */
1444         if (insertions || deletions == 0) {
1445                 /*
1446                  * TRANSLATORS: "+" in (+) is a line addition marker;
1447                  * do not translate it.
1448                  */
1449                 strbuf_addf(&sb,
1450                             (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1451                             insertions);
1452         }
1453
1454         if (deletions || insertions == 0) {
1455                 /*
1456                  * TRANSLATORS: "-" in (-) is a line removal marker;
1457                  * do not translate it.
1458                  */
1459                 strbuf_addf(&sb,
1460                             (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1461                             deletions);
1462         }
1463         strbuf_addch(&sb, '\n');
1464         ret = fputs(sb.buf, fp);
1465         strbuf_release(&sb);
1466         return ret;
1467 }
1468
1469 static void show_stats(struct diffstat_t *data, struct diff_options *options)
1470 {
1471         int i, len, add, del, adds = 0, dels = 0;
1472         uintmax_t max_change = 0, max_len = 0;
1473         int total_files = data->nr, count;
1474         int width, name_width, graph_width, number_width = 0, bin_width = 0;
1475         const char *reset, *add_c, *del_c;
1476         const char *line_prefix = "";
1477         int extra_shown = 0;
1478         struct strbuf *msg = NULL;
1479
1480         if (data->nr == 0)
1481                 return;
1482
1483         if (options->output_prefix) {
1484                 msg = options->output_prefix(options, options->output_prefix_data);
1485                 line_prefix = msg->buf;
1486         }
1487
1488         count = options->stat_count ? options->stat_count : data->nr;
1489
1490         reset = diff_get_color_opt(options, DIFF_RESET);
1491         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1492         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1493
1494         /*
1495          * Find the longest filename and max number of changes
1496          */
1497         for (i = 0; (i < count) && (i < data->nr); i++) {
1498                 struct diffstat_file *file = data->files[i];
1499                 uintmax_t change = file->added + file->deleted;
1500
1501                 if (!file->is_interesting && (change == 0)) {
1502                         count++; /* not shown == room for one more */
1503                         continue;
1504                 }
1505                 fill_print_name(file);
1506                 len = strlen(file->print_name);
1507                 if (max_len < len)
1508                         max_len = len;
1509
1510                 if (file->is_unmerged) {
1511                         /* "Unmerged" is 8 characters */
1512                         bin_width = bin_width < 8 ? 8 : bin_width;
1513                         continue;
1514                 }
1515                 if (file->is_binary) {
1516                         /* "Bin XXX -> YYY bytes" */
1517                         int w = 14 + decimal_width(file->added)
1518                                 + decimal_width(file->deleted);
1519                         bin_width = bin_width < w ? w : bin_width;
1520                         /* Display change counts aligned with "Bin" */
1521                         number_width = 3;
1522                         continue;
1523                 }
1524
1525                 if (max_change < change)
1526                         max_change = change;
1527         }
1528         count = i; /* where we can stop scanning in data->files[] */
1529
1530         /*
1531          * We have width = stat_width or term_columns() columns total.
1532          * We want a maximum of min(max_len, stat_name_width) for the name part.
1533          * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1534          * We also need 1 for " " and 4 + decimal_width(max_change)
1535          * for " | NNNN " and one the empty column at the end, altogether
1536          * 6 + decimal_width(max_change).
1537          *
1538          * If there's not enough space, we will use the smaller of
1539          * stat_name_width (if set) and 5/8*width for the filename,
1540          * and the rest for constant elements + graph part, but no more
1541          * than stat_graph_width for the graph part.
1542          * (5/8 gives 50 for filename and 30 for the constant parts + graph
1543          * for the standard terminal size).
1544          *
1545          * In other words: stat_width limits the maximum width, and
1546          * stat_name_width fixes the maximum width of the filename,
1547          * and is also used to divide available columns if there
1548          * aren't enough.
1549          *
1550          * Binary files are displayed with "Bin XXX -> YYY bytes"
1551          * instead of the change count and graph. This part is treated
1552          * similarly to the graph part, except that it is not
1553          * "scaled". If total width is too small to accomodate the
1554          * guaranteed minimum width of the filename part and the
1555          * separators and this message, this message will "overflow"
1556          * making the line longer than the maximum width.
1557          */
1558
1559         if (options->stat_width == -1)
1560                 width = term_columns() - options->output_prefix_length;
1561         else
1562                 width = options->stat_width ? options->stat_width : 80;
1563         number_width = decimal_width(max_change) > number_width ?
1564                 decimal_width(max_change) : number_width;
1565
1566         if (options->stat_graph_width == -1)
1567                 options->stat_graph_width = diff_stat_graph_width;
1568
1569         /*
1570          * Guarantee 3/8*16==6 for the graph part
1571          * and 5/8*16==10 for the filename part
1572          */
1573         if (width < 16 + 6 + number_width)
1574                 width = 16 + 6 + number_width;
1575
1576         /*
1577          * First assign sizes that are wanted, ignoring available width.
1578          * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1579          * starting from "XXX" should fit in graph_width.
1580          */
1581         graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1582         if (options->stat_graph_width &&
1583             options->stat_graph_width < graph_width)
1584                 graph_width = options->stat_graph_width;
1585
1586         name_width = (options->stat_name_width > 0 &&
1587                       options->stat_name_width < max_len) ?
1588                 options->stat_name_width : max_len;
1589
1590         /*
1591          * Adjust adjustable widths not to exceed maximum width
1592          */
1593         if (name_width + number_width + 6 + graph_width > width) {
1594                 if (graph_width > width * 3/8 - number_width - 6) {
1595                         graph_width = width * 3/8 - number_width - 6;
1596                         if (graph_width < 6)
1597                                 graph_width = 6;
1598                 }
1599
1600                 if (options->stat_graph_width &&
1601                     graph_width > options->stat_graph_width)
1602                         graph_width = options->stat_graph_width;
1603                 if (name_width > width - number_width - 6 - graph_width)
1604                         name_width = width - number_width - 6 - graph_width;
1605                 else
1606                         graph_width = width - number_width - 6 - name_width;
1607         }
1608
1609         /*
1610          * From here name_width is the width of the name area,
1611          * and graph_width is the width of the graph area.
1612          * max_change is used to scale graph properly.
1613          */
1614         for (i = 0; i < count; i++) {
1615                 const char *prefix = "";
1616                 struct diffstat_file *file = data->files[i];
1617                 char *name = file->print_name;
1618                 uintmax_t added = file->added;
1619                 uintmax_t deleted = file->deleted;
1620                 int name_len;
1621
1622                 if (!file->is_interesting && (added + deleted == 0))
1623                         continue;
1624
1625                 /*
1626                  * "scale" the filename
1627                  */
1628                 len = name_width;
1629                 name_len = strlen(name);
1630                 if (name_width < name_len) {
1631                         char *slash;
1632                         prefix = "...";
1633                         len -= 3;
1634                         name += name_len - len;
1635                         slash = strchr(name, '/');
1636                         if (slash)
1637                                 name = slash;
1638                 }
1639
1640                 if (file->is_binary) {
1641                         fprintf(options->file, "%s", line_prefix);
1642                         show_name(options->file, prefix, name, len);
1643                         fprintf(options->file, " %*s", number_width, "Bin");
1644                         if (!added && !deleted) {
1645                                 putc('\n', options->file);
1646                                 continue;
1647                         }
1648                         fprintf(options->file, " %s%"PRIuMAX"%s",
1649                                 del_c, deleted, reset);
1650                         fprintf(options->file, " -> ");
1651                         fprintf(options->file, "%s%"PRIuMAX"%s",
1652                                 add_c, added, reset);
1653                         fprintf(options->file, " bytes");
1654                         fprintf(options->file, "\n");
1655                         continue;
1656                 }
1657                 else if (file->is_unmerged) {
1658                         fprintf(options->file, "%s", line_prefix);
1659                         show_name(options->file, prefix, name, len);
1660                         fprintf(options->file, " Unmerged\n");
1661                         continue;
1662                 }
1663
1664                 /*
1665                  * scale the add/delete
1666                  */
1667                 add = added;
1668                 del = deleted;
1669
1670                 if (graph_width <= max_change) {
1671                         int total = add + del;
1672
1673                         total = scale_linear(add + del, graph_width, max_change);
1674                         if (total < 2 && add && del)
1675                                 /* width >= 2 due to the sanity check */
1676                                 total = 2;
1677                         if (add < del) {
1678                                 add = scale_linear(add, graph_width, max_change);
1679                                 del = total - add;
1680                         } else {
1681                                 del = scale_linear(del, graph_width, max_change);
1682                                 add = total - del;
1683                         }
1684                 }
1685                 fprintf(options->file, "%s", line_prefix);
1686                 show_name(options->file, prefix, name, len);
1687                 fprintf(options->file, " %*"PRIuMAX"%s",
1688                         number_width, added + deleted,
1689                         added + deleted ? " " : "");
1690                 show_graph(options->file, '+', add, add_c, reset);
1691                 show_graph(options->file, '-', del, del_c, reset);
1692                 fprintf(options->file, "\n");
1693         }
1694
1695         for (i = 0; i < data->nr; i++) {
1696                 struct diffstat_file *file = data->files[i];
1697                 uintmax_t added = file->added;
1698                 uintmax_t deleted = file->deleted;
1699
1700                 if (file->is_unmerged ||
1701                     (!file->is_interesting && (added + deleted == 0))) {
1702                         total_files--;
1703                         continue;
1704                 }
1705
1706                 if (!file->is_binary) {
1707                         adds += added;
1708                         dels += deleted;
1709                 }
1710                 if (i < count)
1711                         continue;
1712                 if (!extra_shown)
1713                         fprintf(options->file, "%s ...\n", line_prefix);
1714                 extra_shown = 1;
1715         }
1716         fprintf(options->file, "%s", line_prefix);
1717         print_stat_summary(options->file, total_files, adds, dels);
1718 }
1719
1720 static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1721 {
1722         int i, adds = 0, dels = 0, total_files = data->nr;
1723
1724         if (data->nr == 0)
1725                 return;
1726
1727         for (i = 0; i < data->nr; i++) {
1728                 int added = data->files[i]->added;
1729                 int deleted= data->files[i]->deleted;
1730
1731                 if (data->files[i]->is_unmerged ||
1732                     (!data->files[i]->is_interesting && (added + deleted == 0))) {
1733                         total_files--;
1734                 } else if (!data->files[i]->is_binary) { /* don't count bytes */
1735                         adds += added;
1736                         dels += deleted;
1737                 }
1738         }
1739         if (options->output_prefix) {
1740                 struct strbuf *msg = NULL;
1741                 msg = options->output_prefix(options,
1742                                 options->output_prefix_data);
1743                 fprintf(options->file, "%s", msg->buf);
1744         }
1745         print_stat_summary(options->file, total_files, adds, dels);
1746 }
1747
1748 static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1749 {
1750         int i;
1751
1752         if (data->nr == 0)
1753                 return;
1754
1755         for (i = 0; i < data->nr; i++) {
1756                 struct diffstat_file *file = data->files[i];
1757
1758                 if (options->output_prefix) {
1759                         struct strbuf *msg = NULL;
1760                         msg = options->output_prefix(options,
1761                                         options->output_prefix_data);
1762                         fprintf(options->file, "%s", msg->buf);
1763                 }
1764
1765                 if (file->is_binary)
1766                         fprintf(options->file, "-\t-\t");
1767                 else
1768                         fprintf(options->file,
1769                                 "%"PRIuMAX"\t%"PRIuMAX"\t",
1770                                 file->added, file->deleted);
1771                 if (options->line_termination) {
1772                         fill_print_name(file);
1773                         if (!file->is_renamed)
1774                                 write_name_quoted(file->name, options->file,
1775                                                   options->line_termination);
1776                         else {
1777                                 fputs(file->print_name, options->file);
1778                                 putc(options->line_termination, options->file);
1779                         }
1780                 } else {
1781                         if (file->is_renamed) {
1782                                 putc('\0', options->file);
1783                                 write_name_quoted(file->from_name, options->file, '\0');
1784                         }
1785                         write_name_quoted(file->name, options->file, '\0');
1786                 }
1787         }
1788 }
1789
1790 struct dirstat_file {
1791         const char *name;
1792         unsigned long changed;
1793 };
1794
1795 struct dirstat_dir {
1796         struct dirstat_file *files;
1797         int alloc, nr, permille, cumulative;
1798 };
1799
1800 static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1801                 unsigned long changed, const char *base, int baselen)
1802 {
1803         unsigned long this_dir = 0;
1804         unsigned int sources = 0;
1805         const char *line_prefix = "";
1806         struct strbuf *msg = NULL;
1807
1808         if (opt->output_prefix) {
1809                 msg = opt->output_prefix(opt, opt->output_prefix_data);
1810                 line_prefix = msg->buf;
1811         }
1812
1813         while (dir->nr) {
1814                 struct dirstat_file *f = dir->files;
1815                 int namelen = strlen(f->name);
1816                 unsigned long this;
1817                 char *slash;
1818
1819                 if (namelen < baselen)
1820                         break;
1821                 if (memcmp(f->name, base, baselen))
1822                         break;
1823                 slash = strchr(f->name + baselen, '/');
1824                 if (slash) {
1825                         int newbaselen = slash + 1 - f->name;
1826                         this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1827                         sources++;
1828                 } else {
1829                         this = f->changed;
1830                         dir->files++;
1831                         dir->nr--;
1832                         sources += 2;
1833                 }
1834                 this_dir += this;
1835         }
1836
1837         /*
1838          * We don't report dirstat's for
1839          *  - the top level
1840          *  - or cases where everything came from a single directory
1841          *    under this directory (sources == 1).
1842          */
1843         if (baselen && sources != 1) {
1844                 if (this_dir) {
1845                         int permille = this_dir * 1000 / changed;
1846                         if (permille >= dir->permille) {
1847                                 fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1848                                         permille / 10, permille % 10, baselen, base);
1849                                 if (!dir->cumulative)
1850                                         return 0;
1851                         }
1852                 }
1853         }
1854         return this_dir;
1855 }
1856
1857 static int dirstat_compare(const void *_a, const void *_b)
1858 {
1859         const struct dirstat_file *a = _a;
1860         const struct dirstat_file *b = _b;
1861         return strcmp(a->name, b->name);
1862 }
1863
1864 static void show_dirstat(struct diff_options *options)
1865 {
1866         int i;
1867         unsigned long changed;
1868         struct dirstat_dir dir;
1869         struct diff_queue_struct *q = &diff_queued_diff;
1870
1871         dir.files = NULL;
1872         dir.alloc = 0;
1873         dir.nr = 0;
1874         dir.permille = options->dirstat_permille;
1875         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1876
1877         changed = 0;
1878         for (i = 0; i < q->nr; i++) {
1879                 struct diff_filepair *p = q->queue[i];
1880                 const char *name;
1881                 unsigned long copied, added, damage;
1882                 int content_changed;
1883
1884                 name = p->two->path ? p->two->path : p->one->path;
1885
1886                 if (p->one->sha1_valid && p->two->sha1_valid)
1887                         content_changed = hashcmp(p->one->sha1, p->two->sha1);
1888                 else
1889                         content_changed = 1;
1890
1891                 if (!content_changed) {
1892                         /*
1893                          * The SHA1 has not changed, so pre-/post-content is
1894                          * identical. We can therefore skip looking at the
1895                          * file contents altogether.
1896                          */
1897                         damage = 0;
1898                         goto found_damage;
1899                 }
1900
1901                 if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1902                         /*
1903                          * In --dirstat-by-file mode, we don't really need to
1904                          * look at the actual file contents at all.
1905                          * The fact that the SHA1 changed is enough for us to
1906                          * add this file to the list of results
1907                          * (with each file contributing equal damage).
1908                          */
1909                         damage = 1;
1910                         goto found_damage;
1911                 }
1912
1913                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1914                         diff_populate_filespec(p->one, 0);
1915                         diff_populate_filespec(p->two, 0);
1916                         diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1917                                                &copied, &added);
1918                         diff_free_filespec_data(p->one);
1919                         diff_free_filespec_data(p->two);
1920                 } else if (DIFF_FILE_VALID(p->one)) {
1921                         diff_populate_filespec(p->one, 1);
1922                         copied = added = 0;
1923                         diff_free_filespec_data(p->one);
1924                 } else if (DIFF_FILE_VALID(p->two)) {
1925                         diff_populate_filespec(p->two, 1);
1926                         copied = 0;
1927                         added = p->two->size;
1928                         diff_free_filespec_data(p->two);
1929                 } else
1930                         continue;
1931
1932                 /*
1933                  * Original minus copied is the removed material,
1934                  * added is the new material.  They are both damages
1935                  * made to the preimage.
1936                  * If the resulting damage is zero, we know that
1937                  * diffcore_count_changes() considers the two entries to
1938                  * be identical, but since content_changed is true, we
1939                  * know that there must have been _some_ kind of change,
1940                  * so we force all entries to have damage > 0.
1941                  */
1942                 damage = (p->one->size - copied) + added;
1943                 if (!damage)
1944                         damage = 1;
1945
1946 found_damage:
1947                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1948                 dir.files[dir.nr].name = name;
1949                 dir.files[dir.nr].changed = damage;
1950                 changed += damage;
1951                 dir.nr++;
1952         }
1953
1954         /* This can happen even with many files, if everything was renames */
1955         if (!changed)
1956                 return;
1957
1958         /* Show all directories with more than x% of the changes */
1959         qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1960         gather_dirstat(options, &dir, changed, "", 0);
1961 }
1962
1963 static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
1964 {
1965         int i;
1966         unsigned long changed;
1967         struct dirstat_dir dir;
1968
1969         if (data->nr == 0)
1970                 return;
1971
1972         dir.files = NULL;
1973         dir.alloc = 0;
1974         dir.nr = 0;
1975         dir.permille = options->dirstat_permille;
1976         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1977
1978         changed = 0;
1979         for (i = 0; i < data->nr; i++) {
1980                 struct diffstat_file *file = data->files[i];
1981                 unsigned long damage = file->added + file->deleted;
1982                 if (file->is_binary)
1983                         /*
1984                          * binary files counts bytes, not lines. Must find some
1985                          * way to normalize binary bytes vs. textual lines.
1986                          * The following heuristic assumes that there are 64
1987                          * bytes per "line".
1988                          * This is stupid and ugly, but very cheap...
1989                          */
1990                         damage = (damage + 63) / 64;
1991                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1992                 dir.files[dir.nr].name = file->name;
1993                 dir.files[dir.nr].changed = damage;
1994                 changed += damage;
1995                 dir.nr++;
1996         }
1997
1998         /* This can happen even with many files, if everything was renames */
1999         if (!changed)
2000                 return;
2001
2002         /* Show all directories with more than x% of the changes */
2003         qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
2004         gather_dirstat(options, &dir, changed, "", 0);
2005 }
2006
2007 static void free_diffstat_info(struct diffstat_t *diffstat)
2008 {
2009         int i;
2010         for (i = 0; i < diffstat->nr; i++) {
2011                 struct diffstat_file *f = diffstat->files[i];
2012                 if (f->name != f->print_name)
2013                         free(f->print_name);
2014                 free(f->name);
2015                 free(f->from_name);
2016                 free(f);
2017         }
2018         free(diffstat->files);
2019 }
2020
2021 struct checkdiff_t {
2022         const char *filename;
2023         int lineno;
2024         int conflict_marker_size;
2025         struct diff_options *o;
2026         unsigned ws_rule;
2027         unsigned status;
2028 };
2029
2030 static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2031 {
2032         char firstchar;
2033         int cnt;
2034
2035         if (len < marker_size + 1)
2036                 return 0;
2037         firstchar = line[0];
2038         switch (firstchar) {
2039         case '=': case '>': case '<': case '|':
2040                 break;
2041         default:
2042                 return 0;
2043         }
2044         for (cnt = 1; cnt < marker_size; cnt++)
2045                 if (line[cnt] != firstchar)
2046                         return 0;
2047         /* line[1] thru line[marker_size-1] are same as firstchar */
2048         if (len < marker_size + 1 || !isspace(line[marker_size]))
2049                 return 0;
2050         return 1;
2051 }
2052
2053 static void checkdiff_consume(void *priv, char *line, unsigned long len)
2054 {
2055         struct checkdiff_t *data = priv;
2056         int marker_size = data->conflict_marker_size;
2057         const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2058         const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2059         const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2060         char *err;
2061         char *line_prefix = "";
2062         struct strbuf *msgbuf;
2063
2064         assert(data->o);
2065         if (data->o->output_prefix) {
2066                 msgbuf = data->o->output_prefix(data->o,
2067                         data->o->output_prefix_data);
2068                 line_prefix = msgbuf->buf;
2069         }
2070
2071         if (line[0] == '+') {
2072                 unsigned bad;
2073                 data->lineno++;
2074                 if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2075                         data->status |= 1;
2076                         fprintf(data->o->file,
2077                                 "%s%s:%d: leftover conflict marker\n",
2078                                 line_prefix, data->filename, data->lineno);
2079                 }
2080                 bad = ws_check(line + 1, len - 1, data->ws_rule);
2081                 if (!bad)
2082                         return;
2083                 data->status |= bad;
2084                 err = whitespace_error_string(bad);
2085                 fprintf(data->o->file, "%s%s:%d: %s.\n",
2086                         line_prefix, data->filename, data->lineno, err);
2087                 free(err);
2088                 emit_line(data->o, set, reset, line, 1);
2089                 ws_check_emit(line + 1, len - 1, data->ws_rule,
2090                               data->o->file, set, reset, ws);
2091         } else if (line[0] == ' ') {
2092                 data->lineno++;
2093         } else if (line[0] == '@') {
2094                 char *plus = strchr(line, '+');
2095                 if (plus)
2096                         data->lineno = strtol(plus, NULL, 10) - 1;
2097                 else
2098                         die("invalid diff");
2099         }
2100 }
2101
2102 static unsigned char *deflate_it(char *data,
2103                                  unsigned long size,
2104                                  unsigned long *result_size)
2105 {
2106         int bound;
2107         unsigned char *deflated;
2108         git_zstream stream;
2109
2110         memset(&stream, 0, sizeof(stream));
2111         git_deflate_init(&stream, zlib_compression_level);
2112         bound = git_deflate_bound(&stream, size);
2113         deflated = xmalloc(bound);
2114         stream.next_out = deflated;
2115         stream.avail_out = bound;
2116
2117         stream.next_in = (unsigned char *)data;
2118         stream.avail_in = size;
2119         while (git_deflate(&stream, Z_FINISH) == Z_OK)
2120                 ; /* nothing */
2121         git_deflate_end(&stream);
2122         *result_size = stream.total_out;
2123         return deflated;
2124 }
2125
2126 static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2127                                   const char *prefix)
2128 {
2129         void *cp;
2130         void *delta;
2131         void *deflated;
2132         void *data;
2133         unsigned long orig_size;
2134         unsigned long delta_size;
2135         unsigned long deflate_size;
2136         unsigned long data_size;
2137
2138         /* We could do deflated delta, or we could do just deflated two,
2139          * whichever is smaller.
2140          */
2141         delta = NULL;
2142         deflated = deflate_it(two->ptr, two->size, &deflate_size);
2143         if (one->size && two->size) {
2144                 delta = diff_delta(one->ptr, one->size,
2145                                    two->ptr, two->size,
2146                                    &delta_size, deflate_size);
2147                 if (delta) {
2148                         void *to_free = delta;
2149                         orig_size = delta_size;
2150                         delta = deflate_it(delta, delta_size, &delta_size);
2151                         free(to_free);
2152                 }
2153         }
2154
2155         if (delta && delta_size < deflate_size) {
2156                 fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2157                 free(deflated);
2158                 data = delta;
2159                 data_size = delta_size;
2160         }
2161         else {
2162                 fprintf(file, "%sliteral %lu\n", prefix, two->size);
2163                 free(delta);
2164                 data = deflated;
2165                 data_size = deflate_size;
2166         }
2167
2168         /* emit data encoded in base85 */
2169         cp = data;
2170         while (data_size) {
2171                 int bytes = (52 < data_size) ? 52 : data_size;
2172                 char line[70];
2173                 data_size -= bytes;
2174                 if (bytes <= 26)
2175                         line[0] = bytes + 'A' - 1;
2176                 else
2177                         line[0] = bytes - 26 + 'a' - 1;
2178                 encode_85(line + 1, cp, bytes);
2179                 cp = (char *) cp + bytes;
2180                 fprintf(file, "%s", prefix);
2181                 fputs(line, file);
2182                 fputc('\n', file);
2183         }
2184         fprintf(file, "%s\n", prefix);
2185         free(data);
2186 }
2187
2188 static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2189                              const char *prefix)
2190 {
2191         fprintf(file, "%sGIT binary patch\n", prefix);
2192         emit_binary_diff_body(file, one, two, prefix);
2193         emit_binary_diff_body(file, two, one, prefix);
2194 }
2195
2196 int diff_filespec_is_binary(struct diff_filespec *one)
2197 {
2198         if (one->is_binary == -1) {
2199                 diff_filespec_load_driver(one);
2200                 if (one->driver->binary != -1)
2201                         one->is_binary = one->driver->binary;
2202                 else {
2203                         if (!one->data && DIFF_FILE_VALID(one))
2204                                 diff_populate_filespec(one, 0);
2205                         if (one->data)
2206                                 one->is_binary = buffer_is_binary(one->data,
2207                                                 one->size);
2208                         if (one->is_binary == -1)
2209                                 one->is_binary = 0;
2210                 }
2211         }
2212         return one->is_binary;
2213 }
2214
2215 static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2216 {
2217         diff_filespec_load_driver(one);
2218         return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2219 }
2220
2221 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2222 {
2223         if (!options->a_prefix)
2224                 options->a_prefix = a;
2225         if (!options->b_prefix)
2226                 options->b_prefix = b;
2227 }
2228
2229 struct userdiff_driver *get_textconv(struct diff_filespec *one)
2230 {
2231         if (!DIFF_FILE_VALID(one))
2232                 return NULL;
2233
2234         diff_filespec_load_driver(one);
2235         return userdiff_get_textconv(one->driver);
2236 }
2237
2238 static void builtin_diff(const char *name_a,
2239                          const char *name_b,
2240                          struct diff_filespec *one,
2241                          struct diff_filespec *two,
2242                          const char *xfrm_msg,
2243                          int must_show_header,
2244                          struct diff_options *o,
2245                          int complete_rewrite)
2246 {
2247         mmfile_t mf1, mf2;
2248         const char *lbl[2];
2249         char *a_one, *b_two;
2250         const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2251         const char *reset = diff_get_color_opt(o, DIFF_RESET);
2252         const char *a_prefix, *b_prefix;
2253         struct userdiff_driver *textconv_one = NULL;
2254         struct userdiff_driver *textconv_two = NULL;
2255         struct strbuf header = STRBUF_INIT;
2256         struct strbuf *msgbuf;
2257         char *line_prefix = "";
2258
2259         if (o->output_prefix) {
2260                 msgbuf = o->output_prefix(o, o->output_prefix_data);
2261                 line_prefix = msgbuf->buf;
2262         }
2263
2264         if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2265                         (!one->mode || S_ISGITLINK(one->mode)) &&
2266                         (!two->mode || S_ISGITLINK(two->mode))) {
2267                 const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2268                 const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2269                 show_submodule_summary(o->file, one ? one->path : two->path,
2270                                 one->sha1, two->sha1, two->dirty_submodule,
2271                                 meta, del, add, reset);
2272                 return;
2273         }
2274
2275         if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2276                 textconv_one = get_textconv(one);
2277                 textconv_two = get_textconv(two);
2278         }
2279
2280         diff_set_mnemonic_prefix(o, "a/", "b/");
2281         if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2282                 a_prefix = o->b_prefix;
2283                 b_prefix = o->a_prefix;
2284         } else {
2285                 a_prefix = o->a_prefix;
2286                 b_prefix = o->b_prefix;
2287         }
2288
2289         /* Never use a non-valid filename anywhere if at all possible */
2290         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2291         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2292
2293         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2294         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2295         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2296         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2297         strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2298         if (lbl[0][0] == '/') {
2299                 /* /dev/null */
2300                 strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2301                 if (xfrm_msg)
2302                         strbuf_addstr(&header, xfrm_msg);
2303                 must_show_header = 1;
2304         }
2305         else if (lbl[1][0] == '/') {
2306                 strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2307                 if (xfrm_msg)
2308                         strbuf_addstr(&header, xfrm_msg);
2309                 must_show_header = 1;
2310         }
2311         else {
2312                 if (one->mode != two->mode) {
2313                         strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2314                         strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2315                         must_show_header = 1;
2316                 }
2317                 if (xfrm_msg)
2318                         strbuf_addstr(&header, xfrm_msg);
2319
2320                 /*
2321                  * we do not run diff between different kind
2322                  * of objects.
2323                  */
2324                 if ((one->mode ^ two->mode) & S_IFMT)
2325                         goto free_ab_and_return;
2326                 if (complete_rewrite &&
2327                     (textconv_one || !diff_filespec_is_binary(one)) &&
2328                     (textconv_two || !diff_filespec_is_binary(two))) {
2329                         fprintf(o->file, "%s", header.buf);
2330                         strbuf_reset(&header);
2331                         emit_rewrite_diff(name_a, name_b, one, two,
2332                                                 textconv_one, textconv_two, o);
2333                         o->found_changes = 1;
2334                         goto free_ab_and_return;
2335                 }
2336         }
2337
2338         if (o->irreversible_delete && lbl[1][0] == '/') {
2339                 fprintf(o->file, "%s", header.buf);
2340                 strbuf_reset(&header);
2341                 goto free_ab_and_return;
2342         } else if (!DIFF_OPT_TST(o, TEXT) &&
2343             ( (!textconv_one && diff_filespec_is_binary(one)) ||
2344               (!textconv_two && diff_filespec_is_binary(two)) )) {
2345                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2346                         die("unable to read files to diff");
2347                 /* Quite common confusing case */
2348                 if (mf1.size == mf2.size &&
2349                     !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2350                         if (must_show_header)
2351                                 fprintf(o->file, "%s", header.buf);
2352                         goto free_ab_and_return;
2353                 }
2354                 fprintf(o->file, "%s", header.buf);
2355                 strbuf_reset(&header);
2356                 if (DIFF_OPT_TST(o, BINARY))
2357                         emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2358                 else
2359                         fprintf(o->file, "%sBinary files %s and %s differ\n",
2360                                 line_prefix, lbl[0], lbl[1]);
2361                 o->found_changes = 1;
2362         } else {
2363                 /* Crazy xdl interfaces.. */
2364                 const char *diffopts = getenv("GIT_DIFF_OPTS");
2365                 xpparam_t xpp;
2366                 xdemitconf_t xecfg;
2367                 struct emit_callback ecbdata;
2368                 const struct userdiff_funcname *pe;
2369
2370                 if (must_show_header) {
2371                         fprintf(o->file, "%s", header.buf);
2372                         strbuf_reset(&header);
2373                 }
2374
2375                 mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2376                 mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2377
2378                 pe = diff_funcname_pattern(one);
2379                 if (!pe)
2380                         pe = diff_funcname_pattern(two);
2381
2382                 memset(&xpp, 0, sizeof(xpp));
2383                 memset(&xecfg, 0, sizeof(xecfg));
2384                 memset(&ecbdata, 0, sizeof(ecbdata));
2385                 ecbdata.label_path = lbl;
2386                 ecbdata.color_diff = want_color(o->use_color);
2387                 ecbdata.found_changesp = &o->found_changes;
2388                 ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
2389                 if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2390                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
2391                 ecbdata.opt = o;
2392                 ecbdata.header = header.len ? &header : NULL;
2393                 xpp.flags = o->xdl_opts;
2394                 xecfg.ctxlen = o->context;
2395                 xecfg.interhunkctxlen = o->interhunkcontext;
2396                 xecfg.flags = XDL_EMIT_FUNCNAMES;
2397                 if (DIFF_OPT_TST(o, FUNCCONTEXT))
2398                         xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2399                 if (pe)
2400                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2401                 if (!diffopts)
2402                         ;
2403                 else if (!prefixcmp(diffopts, "--unified="))
2404                         xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
2405                 else if (!prefixcmp(diffopts, "-u"))
2406                         xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
2407                 if (o->word_diff)
2408                         init_diff_words_data(&ecbdata, o, one, two);
2409                 xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2410                               &xpp, &xecfg);
2411                 if (o->word_diff)
2412                         free_diff_words_data(&ecbdata);
2413                 if (textconv_one)
2414                         free(mf1.ptr);
2415                 if (textconv_two)
2416                         free(mf2.ptr);
2417                 xdiff_clear_find_func(&xecfg);
2418         }
2419
2420  free_ab_and_return:
2421         strbuf_release(&header);
2422         diff_free_filespec_data(one);
2423         diff_free_filespec_data(two);
2424         free(a_one);
2425         free(b_two);
2426         return;
2427 }
2428
2429 static void builtin_diffstat(const char *name_a, const char *name_b,
2430                              struct diff_filespec *one,
2431                              struct diff_filespec *two,
2432                              struct diffstat_t *diffstat,
2433                              struct diff_options *o,
2434                              struct diff_filepair *p)
2435 {
2436         mmfile_t mf1, mf2;
2437         struct diffstat_file *data;
2438         int same_contents;
2439         int complete_rewrite = 0;
2440
2441         if (!DIFF_PAIR_UNMERGED(p)) {
2442                 if (p->status == DIFF_STATUS_MODIFIED && p->score)
2443                         complete_rewrite = 1;
2444         }
2445
2446         data = diffstat_add(diffstat, name_a, name_b);
2447         data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2448
2449         if (!one || !two) {
2450                 data->is_unmerged = 1;
2451                 return;
2452         }
2453
2454         same_contents = !hashcmp(one->sha1, two->sha1);
2455
2456         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2457                 data->is_binary = 1;
2458                 if (same_contents) {
2459                         data->added = 0;
2460                         data->deleted = 0;
2461                 } else {
2462                         data->added = diff_filespec_size(two);
2463                         data->deleted = diff_filespec_size(one);
2464                 }
2465         }
2466
2467         else if (complete_rewrite) {
2468                 diff_populate_filespec(one, 0);
2469                 diff_populate_filespec(two, 0);
2470                 data->deleted = count_lines(one->data, one->size);
2471                 data->added = count_lines(two->data, two->size);
2472         }
2473
2474         else if (!same_contents) {
2475                 /* Crazy xdl interfaces.. */
2476                 xpparam_t xpp;
2477                 xdemitconf_t xecfg;
2478
2479                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2480                         die("unable to read files to diff");
2481
2482                 memset(&xpp, 0, sizeof(xpp));
2483                 memset(&xecfg, 0, sizeof(xecfg));
2484                 xpp.flags = o->xdl_opts;
2485                 xecfg.ctxlen = o->context;
2486                 xecfg.interhunkctxlen = o->interhunkcontext;
2487                 xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2488                               &xpp, &xecfg);
2489         }
2490
2491         diff_free_filespec_data(one);
2492         diff_free_filespec_data(two);
2493 }
2494
2495 static void builtin_checkdiff(const char *name_a, const char *name_b,
2496                               const char *attr_path,
2497                               struct diff_filespec *one,
2498                               struct diff_filespec *two,
2499                               struct diff_options *o)
2500 {
2501         mmfile_t mf1, mf2;
2502         struct checkdiff_t data;
2503
2504         if (!two)
2505                 return;
2506
2507         memset(&data, 0, sizeof(data));
2508         data.filename = name_b ? name_b : name_a;
2509         data.lineno = 0;
2510         data.o = o;
2511         data.ws_rule = whitespace_rule(attr_path);
2512         data.conflict_marker_size = ll_merge_marker_size(attr_path);
2513
2514         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2515                 die("unable to read files to diff");
2516
2517         /*
2518          * All the other codepaths check both sides, but not checking
2519          * the "old" side here is deliberate.  We are checking the newly
2520          * introduced changes, and as long as the "new" side is text, we
2521          * can and should check what it introduces.
2522          */
2523         if (diff_filespec_is_binary(two))
2524                 goto free_and_return;
2525         else {
2526                 /* Crazy xdl interfaces.. */
2527                 xpparam_t xpp;
2528                 xdemitconf_t xecfg;
2529
2530                 memset(&xpp, 0, sizeof(xpp));
2531                 memset(&xecfg, 0, sizeof(xecfg));
2532                 xecfg.ctxlen = 1; /* at least one context line */
2533                 xpp.flags = 0;
2534                 xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2535                               &xpp, &xecfg);
2536
2537                 if (data.ws_rule & WS_BLANK_AT_EOF) {
2538                         struct emit_callback ecbdata;
2539                         int blank_at_eof;
2540
2541                         ecbdata.ws_rule = data.ws_rule;
2542                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
2543                         blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2544
2545                         if (blank_at_eof) {
2546                                 static char *err;
2547                                 if (!err)
2548                                         err = whitespace_error_string(WS_BLANK_AT_EOF);
2549                                 fprintf(o->file, "%s:%d: %s.\n",
2550                                         data.filename, blank_at_eof, err);
2551                                 data.status = 1; /* report errors */
2552                         }
2553                 }
2554         }
2555  free_and_return:
2556         diff_free_filespec_data(one);
2557         diff_free_filespec_data(two);
2558         if (data.status)
2559                 DIFF_OPT_SET(o, CHECK_FAILED);
2560 }
2561
2562 struct diff_filespec *alloc_filespec(const char *path)
2563 {
2564         int namelen = strlen(path);
2565         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
2566
2567         memset(spec, 0, sizeof(*spec));
2568         spec->path = (char *)(spec + 1);
2569         memcpy(spec->path, path, namelen+1);
2570         spec->count = 1;
2571         spec->is_binary = -1;
2572         return spec;
2573 }
2574
2575 void free_filespec(struct diff_filespec *spec)
2576 {
2577         if (!--spec->count) {
2578                 diff_free_filespec_data(spec);
2579                 free(spec);
2580         }
2581 }
2582
2583 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2584                    int sha1_valid, unsigned short mode)
2585 {
2586         if (mode) {
2587                 spec->mode = canon_mode(mode);
2588                 hashcpy(spec->sha1, sha1);
2589                 spec->sha1_valid = sha1_valid;
2590         }
2591 }
2592
2593 /*
2594  * Given a name and sha1 pair, if the index tells us the file in
2595  * the work tree has that object contents, return true, so that
2596  * prepare_temp_file() does not have to inflate and extract.
2597  */
2598 static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2599 {
2600         struct cache_entry *ce;
2601         struct stat st;
2602         int pos, len;
2603
2604         /*
2605          * We do not read the cache ourselves here, because the
2606          * benchmark with my previous version that always reads cache
2607          * shows that it makes things worse for diff-tree comparing
2608          * two linux-2.6 kernel trees in an already checked out work
2609          * tree.  This is because most diff-tree comparisons deal with
2610          * only a small number of files, while reading the cache is
2611          * expensive for a large project, and its cost outweighs the
2612          * savings we get by not inflating the object to a temporary
2613          * file.  Practically, this code only helps when we are used
2614          * by diff-cache --cached, which does read the cache before
2615          * calling us.
2616          */
2617         if (!active_cache)
2618                 return 0;
2619
2620         /* We want to avoid the working directory if our caller
2621          * doesn't need the data in a normal file, this system
2622          * is rather slow with its stat/open/mmap/close syscalls,
2623          * and the object is contained in a pack file.  The pack
2624          * is probably already open and will be faster to obtain
2625          * the data through than the working directory.  Loose
2626          * objects however would tend to be slower as they need
2627          * to be individually opened and inflated.
2628          */
2629         if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2630                 return 0;
2631
2632         len = strlen(name);
2633         pos = cache_name_pos(name, len);
2634         if (pos < 0)
2635                 return 0;
2636         ce = active_cache[pos];
2637
2638         /*
2639          * This is not the sha1 we are looking for, or
2640          * unreusable because it is not a regular file.
2641          */
2642         if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2643                 return 0;
2644
2645         /*
2646          * If ce is marked as "assume unchanged", there is no
2647          * guarantee that work tree matches what we are looking for.
2648          */
2649         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2650                 return 0;
2651
2652         /*
2653          * If ce matches the file in the work tree, we can reuse it.
2654          */
2655         if (ce_uptodate(ce) ||
2656             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2657                 return 1;
2658
2659         return 0;
2660 }
2661
2662 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2663 {
2664         int len;
2665         char *data = xmalloc(100), *dirty = "";
2666
2667         /* Are we looking at the work tree? */
2668         if (s->dirty_submodule)
2669                 dirty = "-dirty";
2670
2671         len = snprintf(data, 100,
2672                        "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2673         s->data = data;
2674         s->size = len;
2675         s->should_free = 1;
2676         if (size_only) {
2677                 s->data = NULL;
2678                 free(data);
2679         }
2680         return 0;
2681 }
2682
2683 /*
2684  * While doing rename detection and pickaxe operation, we may need to
2685  * grab the data for the blob (or file) for our own in-core comparison.
2686  * diff_filespec has data and size fields for this purpose.
2687  */
2688 int diff_populate_filespec(struct diff_filespec *s, int size_only)
2689 {
2690         int err = 0;
2691         if (!DIFF_FILE_VALID(s))
2692                 die("internal error: asking to populate invalid file.");
2693         if (S_ISDIR(s->mode))
2694                 return -1;
2695
2696         if (s->data)
2697                 return 0;
2698
2699         if (size_only && 0 < s->size)
2700                 return 0;
2701
2702         if (S_ISGITLINK(s->mode))
2703                 return diff_populate_gitlink(s, size_only);
2704
2705         if (!s->sha1_valid ||
2706             reuse_worktree_file(s->path, s->sha1, 0)) {
2707                 struct strbuf buf = STRBUF_INIT;
2708                 struct stat st;
2709                 int fd;
2710
2711                 if (lstat(s->path, &st) < 0) {
2712                         if (errno == ENOENT) {
2713                         err_empty:
2714                                 err = -1;
2715                         empty:
2716                                 s->data = (char *)"";
2717                                 s->size = 0;
2718                                 return err;
2719                         }
2720                 }
2721                 s->size = xsize_t(st.st_size);
2722                 if (!s->size)
2723                         goto empty;
2724                 if (S_ISLNK(st.st_mode)) {
2725                         struct strbuf sb = STRBUF_INIT;
2726
2727                         if (strbuf_readlink(&sb, s->path, s->size))
2728                                 goto err_empty;
2729                         s->size = sb.len;
2730                         s->data = strbuf_detach(&sb, NULL);
2731                         s->should_free = 1;
2732                         return 0;
2733                 }
2734                 if (size_only)
2735                         return 0;
2736                 fd = open(s->path, O_RDONLY);
2737                 if (fd < 0)
2738                         goto err_empty;
2739                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2740                 close(fd);
2741                 s->should_munmap = 1;
2742
2743                 /*
2744                  * Convert from working tree format to canonical git format
2745                  */
2746                 if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
2747                         size_t size = 0;
2748                         munmap(s->data, s->size);
2749                         s->should_munmap = 0;
2750                         s->data = strbuf_detach(&buf, &size);
2751                         s->size = size;
2752                         s->should_free = 1;
2753                 }
2754         }
2755         else {
2756                 enum object_type type;
2757                 if (size_only) {
2758                         type = sha1_object_info(s->sha1, &s->size);
2759                         if (type < 0)
2760                                 die("unable to read %s", sha1_to_hex(s->sha1));
2761                 } else {
2762                         s->data = read_sha1_file(s->sha1, &type, &s->size);
2763                         if (!s->data)
2764                                 die("unable to read %s", sha1_to_hex(s->sha1));
2765                         s->should_free = 1;
2766                 }
2767         }
2768         return 0;
2769 }
2770
2771 void diff_free_filespec_blob(struct diff_filespec *s)
2772 {
2773         if (s->should_free)
2774                 free(s->data);
2775         else if (s->should_munmap)
2776                 munmap(s->data, s->size);
2777
2778         if (s->should_free || s->should_munmap) {
2779                 s->should_free = s->should_munmap = 0;
2780                 s->data = NULL;
2781         }
2782 }
2783
2784 void diff_free_filespec_data(struct diff_filespec *s)
2785 {
2786         diff_free_filespec_blob(s);
2787         free(s->cnt_data);
2788         s->cnt_data = NULL;
2789 }
2790
2791 static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2792                            void *blob,
2793                            unsigned long size,
2794                            const unsigned char *sha1,
2795                            int mode)
2796 {
2797         int fd;
2798         struct strbuf buf = STRBUF_INIT;
2799         struct strbuf template = STRBUF_INIT;
2800         char *path_dup = xstrdup(path);
2801         const char *base = basename(path_dup);
2802
2803         /* Generate "XXXXXX_basename.ext" */
2804         strbuf_addstr(&template, "XXXXXX_");
2805         strbuf_addstr(&template, base);
2806
2807         fd = git_mkstemps(temp->tmp_path, PATH_MAX, template.buf,
2808                         strlen(base) + 1);
2809         if (fd < 0)
2810                 die_errno("unable to create temp-file");
2811         if (convert_to_working_tree(path,
2812                         (const char *)blob, (size_t)size, &buf)) {
2813                 blob = buf.buf;
2814                 size = buf.len;
2815         }
2816         if (write_in_full(fd, blob, size) != size)
2817                 die_errno("unable to write temp-file");
2818         close(fd);
2819         temp->name = temp->tmp_path;
2820         strcpy(temp->hex, sha1_to_hex(sha1));
2821         temp->hex[40] = 0;
2822         sprintf(temp->mode, "%06o", mode);
2823         strbuf_release(&buf);
2824         strbuf_release(&template);
2825         free(path_dup);
2826 }
2827
2828 static struct diff_tempfile *prepare_temp_file(const char *name,
2829                 struct diff_filespec *one)
2830 {
2831         struct diff_tempfile *temp = claim_diff_tempfile();
2832
2833         if (!DIFF_FILE_VALID(one)) {
2834         not_a_valid_file:
2835                 /* A '-' entry produces this for file-2, and
2836                  * a '+' entry produces this for file-1.
2837                  */
2838                 temp->name = "/dev/null";
2839                 strcpy(temp->hex, ".");
2840                 strcpy(temp->mode, ".");
2841                 return temp;
2842         }
2843
2844         if (!remove_tempfile_installed) {
2845                 atexit(remove_tempfile);
2846                 sigchain_push_common(remove_tempfile_on_signal);
2847                 remove_tempfile_installed = 1;
2848         }
2849
2850         if (!one->sha1_valid ||
2851             reuse_worktree_file(name, one->sha1, 1)) {
2852                 struct stat st;
2853                 if (lstat(name, &st) < 0) {
2854                         if (errno == ENOENT)
2855                                 goto not_a_valid_file;
2856                         die_errno("stat(%s)", name);
2857                 }
2858                 if (S_ISLNK(st.st_mode)) {
2859                         struct strbuf sb = STRBUF_INIT;
2860                         if (strbuf_readlink(&sb, name, st.st_size) < 0)
2861                                 die_errno("readlink(%s)", name);
2862                         prep_temp_blob(name, temp, sb.buf, sb.len,
2863                                        (one->sha1_valid ?
2864                                         one->sha1 : null_sha1),
2865                                        (one->sha1_valid ?
2866                                         one->mode : S_IFLNK));
2867                         strbuf_release(&sb);
2868                 }
2869                 else {
2870                         /* we can borrow from the file in the work tree */
2871                         temp->name = name;
2872                         if (!one->sha1_valid)
2873                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
2874                         else
2875                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
2876                         /* Even though we may sometimes borrow the
2877                          * contents from the work tree, we always want
2878                          * one->mode.  mode is trustworthy even when
2879                          * !(one->sha1_valid), as long as
2880                          * DIFF_FILE_VALID(one).
2881                          */
2882                         sprintf(temp->mode, "%06o", one->mode);
2883                 }
2884                 return temp;
2885         }
2886         else {
2887                 if (diff_populate_filespec(one, 0))
2888                         die("cannot read data blob for %s", one->path);
2889                 prep_temp_blob(name, temp, one->data, one->size,
2890                                one->sha1, one->mode);
2891         }
2892         return temp;
2893 }
2894
2895 /* An external diff command takes:
2896  *
2897  * diff-cmd name infile1 infile1-sha1 infile1-mode \
2898  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2899  *
2900  */
2901 static void run_external_diff(const char *pgm,
2902                               const char *name,
2903                               const char *other,
2904                               struct diff_filespec *one,
2905                               struct diff_filespec *two,
2906                               const char *xfrm_msg,
2907                               int complete_rewrite)
2908 {
2909         const char *spawn_arg[10];
2910         int retval;
2911         const char **arg = &spawn_arg[0];
2912
2913         if (one && two) {
2914                 struct diff_tempfile *temp_one, *temp_two;
2915                 const char *othername = (other ? other : name);
2916                 temp_one = prepare_temp_file(name, one);
2917                 temp_two = prepare_temp_file(othername, two);
2918                 *arg++ = pgm;
2919                 *arg++ = name;
2920                 *arg++ = temp_one->name;
2921                 *arg++ = temp_one->hex;
2922                 *arg++ = temp_one->mode;
2923                 *arg++ = temp_two->name;
2924                 *arg++ = temp_two->hex;
2925                 *arg++ = temp_two->mode;
2926                 if (other) {
2927                         *arg++ = other;
2928                         *arg++ = xfrm_msg;
2929                 }
2930         } else {
2931                 *arg++ = pgm;
2932                 *arg++ = name;
2933         }
2934         *arg = NULL;
2935         fflush(NULL);
2936         retval = run_command_v_opt(spawn_arg, RUN_USING_SHELL);
2937         remove_tempfile();
2938         if (retval) {
2939                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
2940                 exit(1);
2941         }
2942 }
2943
2944 static int similarity_index(struct diff_filepair *p)
2945 {
2946         return p->score * 100 / MAX_SCORE;
2947 }
2948
2949 static void fill_metainfo(struct strbuf *msg,
2950                           const char *name,
2951                           const char *other,
2952                           struct diff_filespec *one,
2953                           struct diff_filespec *two,
2954                           struct diff_options *o,
2955                           struct diff_filepair *p,
2956                           int *must_show_header,
2957                           int use_color)
2958 {
2959         const char *set = diff_get_color(use_color, DIFF_METAINFO);
2960         const char *reset = diff_get_color(use_color, DIFF_RESET);
2961         struct strbuf *msgbuf;
2962         char *line_prefix = "";
2963
2964         *must_show_header = 1;
2965         if (o->output_prefix) {
2966                 msgbuf = o->output_prefix(o, o->output_prefix_data);
2967                 line_prefix = msgbuf->buf;
2968         }
2969         strbuf_init(msg, PATH_MAX * 2 + 300);
2970         switch (p->status) {
2971         case DIFF_STATUS_COPIED:
2972                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
2973                             line_prefix, set, similarity_index(p));
2974                 strbuf_addf(msg, "%s\n%s%scopy from ",
2975                             reset,  line_prefix, set);
2976                 quote_c_style(name, msg, NULL, 0);
2977                 strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
2978                 quote_c_style(other, msg, NULL, 0);
2979                 strbuf_addf(msg, "%s\n", reset);
2980                 break;
2981         case DIFF_STATUS_RENAMED:
2982                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
2983                             line_prefix, set, similarity_index(p));
2984                 strbuf_addf(msg, "%s\n%s%srename from ",
2985                             reset, line_prefix, set);
2986                 quote_c_style(name, msg, NULL, 0);
2987                 strbuf_addf(msg, "%s\n%s%srename to ",
2988                             reset, line_prefix, set);
2989                 quote_c_style(other, msg, NULL, 0);
2990                 strbuf_addf(msg, "%s\n", reset);
2991                 break;
2992         case DIFF_STATUS_MODIFIED:
2993                 if (p->score) {
2994                         strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
2995                                     line_prefix,
2996                                     set, similarity_index(p), reset);
2997                         break;
2998                 }
2999                 /* fallthru */
3000         default:
3001                 *must_show_header = 0;
3002         }
3003         if (one && two && hashcmp(one->sha1, two->sha1)) {
3004                 int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3005
3006                 if (DIFF_OPT_TST(o, BINARY)) {
3007                         mmfile_t mf;
3008                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3009                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3010                                 abbrev = 40;
3011                 }
3012                 strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
3013                             find_unique_abbrev(one->sha1, abbrev));
3014                 strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
3015                 if (one->mode == two->mode)
3016                         strbuf_addf(msg, " %06o", one->mode);
3017                 strbuf_addf(msg, "%s\n", reset);
3018         }
3019 }
3020
3021 static void run_diff_cmd(const char *pgm,
3022                          const char *name,
3023                          const char *other,
3024                          const char *attr_path,
3025                          struct diff_filespec *one,
3026                          struct diff_filespec *two,
3027                          struct strbuf *msg,
3028                          struct diff_options *o,
3029                          struct diff_filepair *p)
3030 {
3031         const char *xfrm_msg = NULL;
3032         int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3033         int must_show_header = 0;
3034
3035
3036         if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3037                 struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3038                 if (drv && drv->external)
3039                         pgm = drv->external;
3040         }
3041
3042         if (msg) {
3043                 /*
3044                  * don't use colors when the header is intended for an
3045                  * external diff driver
3046                  */
3047                 fill_metainfo(msg, name, other, one, two, o, p,
3048                               &must_show_header,
3049                               want_color(o->use_color) && !pgm);
3050                 xfrm_msg = msg->len ? msg->buf : NULL;
3051         }
3052
3053         if (pgm) {
3054                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
3055                                   complete_rewrite);
3056                 return;
3057         }
3058         if (one && two)
3059                 builtin_diff(name, other ? other : name,
3060                              one, two, xfrm_msg, must_show_header,
3061                              o, complete_rewrite);
3062         else
3063                 fprintf(o->file, "* Unmerged path %s\n", name);
3064 }
3065
3066 static void diff_fill_sha1_info(struct diff_filespec *one)
3067 {
3068         if (DIFF_FILE_VALID(one)) {
3069                 if (!one->sha1_valid) {
3070                         struct stat st;
3071                         if (one->is_stdin) {
3072                                 hashcpy(one->sha1, null_sha1);
3073                                 return;
3074                         }
3075                         if (lstat(one->path, &st) < 0)
3076                                 die_errno("stat '%s'", one->path);
3077                         if (index_path(one->sha1, one->path, &st, 0))
3078                                 die("cannot hash %s", one->path);
3079                 }
3080         }
3081         else
3082                 hashclr(one->sha1);
3083 }
3084
3085 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3086 {
3087         /* Strip the prefix but do not molest /dev/null and absolute paths */
3088         if (*namep && **namep != '/') {
3089                 *namep += prefix_length;
3090                 if (**namep == '/')
3091                         ++*namep;
3092         }
3093         if (*otherp && **otherp != '/') {
3094                 *otherp += prefix_length;
3095                 if (**otherp == '/')
3096                         ++*otherp;
3097         }
3098 }
3099
3100 static void run_diff(struct diff_filepair *p, struct diff_options *o)
3101 {
3102         const char *pgm = external_diff();
3103         struct strbuf msg;
3104         struct diff_filespec *one = p->one;
3105         struct diff_filespec *two = p->two;
3106         const char *name;
3107         const char *other;
3108         const char *attr_path;
3109
3110         name  = p->one->path;
3111         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3112         attr_path = name;
3113         if (o->prefix_length)
3114                 strip_prefix(o->prefix_length, &name, &other);
3115
3116         if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3117                 pgm = NULL;
3118
3119         if (DIFF_PAIR_UNMERGED(p)) {
3120                 run_diff_cmd(pgm, name, NULL, attr_path,
3121                              NULL, NULL, NULL, o, p);
3122                 return;
3123         }
3124
3125         diff_fill_sha1_info(one);
3126         diff_fill_sha1_info(two);
3127
3128         if (!pgm &&
3129             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3130             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3131                 /*
3132                  * a filepair that changes between file and symlink
3133                  * needs to be split into deletion and creation.
3134                  */
3135                 struct diff_filespec *null = alloc_filespec(two->path);
3136                 run_diff_cmd(NULL, name, other, attr_path,
3137                              one, null, &msg, o, p);
3138                 free(null);
3139                 strbuf_release(&msg);
3140
3141                 null = alloc_filespec(one->path);
3142                 run_diff_cmd(NULL, name, other, attr_path,
3143                              null, two, &msg, o, p);
3144                 free(null);
3145         }
3146         else
3147                 run_diff_cmd(pgm, name, other, attr_path,
3148                              one, two, &msg, o, p);
3149
3150         strbuf_release(&msg);
3151 }
3152
3153 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3154                          struct diffstat_t *diffstat)
3155 {
3156         const char *name;
3157         const char *other;
3158
3159         if (DIFF_PAIR_UNMERGED(p)) {
3160                 /* unmerged */
3161                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3162                 return;
3163         }
3164
3165         name = p->one->path;
3166         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3167
3168         if (o->prefix_length)
3169                 strip_prefix(o->prefix_length, &name, &other);
3170
3171         diff_fill_sha1_info(p->one);
3172         diff_fill_sha1_info(p->two);
3173
3174         builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3175 }
3176
3177 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3178 {
3179         const char *name;
3180         const char *other;
3181         const char *attr_path;
3182
3183         if (DIFF_PAIR_UNMERGED(p)) {
3184                 /* unmerged */
3185                 return;
3186         }
3187
3188         name = p->one->path;
3189         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3190         attr_path = other ? other : name;
3191
3192         if (o->prefix_length)
3193                 strip_prefix(o->prefix_length, &name, &other);
3194
3195         diff_fill_sha1_info(p->one);
3196         diff_fill_sha1_info(p->two);
3197
3198         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3199 }
3200
3201 void diff_setup(struct diff_options *options)
3202 {
3203         memcpy(options, &default_diff_options, sizeof(*options));
3204
3205         options->file = stdout;
3206
3207         options->line_termination = '\n';
3208         options->break_opt = -1;
3209         options->rename_limit = -1;
3210         options->dirstat_permille = diff_dirstat_permille_default;
3211         options->context = diff_context_default;
3212         DIFF_OPT_SET(options, RENAME_EMPTY);
3213
3214         options->change = diff_change;
3215         options->add_remove = diff_addremove;
3216         options->use_color = diff_use_color_default;
3217         options->detect_rename = diff_detect_rename_default;
3218
3219         if (diff_no_prefix) {
3220                 options->a_prefix = options->b_prefix = "";
3221         } else if (!diff_mnemonic_prefix) {
3222                 options->a_prefix = "a/";
3223                 options->b_prefix = "b/";
3224         }
3225 }
3226
3227 void diff_setup_done(struct diff_options *options)
3228 {
3229         int count = 0;
3230
3231         if (options->output_format & DIFF_FORMAT_NAME)
3232                 count++;
3233         if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3234                 count++;
3235         if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3236                 count++;
3237         if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3238                 count++;
3239         if (count > 1)
3240                 die("--name-only, --name-status, --check and -s are mutually exclusive");
3241
3242         /*
3243          * Most of the time we can say "there are changes"
3244          * only by checking if there are changed paths, but
3245          * --ignore-whitespace* options force us to look
3246          * inside contents.
3247          */
3248
3249         if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3250             DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3251             DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3252                 DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3253         else
3254                 DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3255
3256         if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3257                 options->detect_rename = DIFF_DETECT_COPY;
3258
3259         if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3260                 options->prefix = NULL;
3261         if (options->prefix)
3262                 options->prefix_length = strlen(options->prefix);
3263         else
3264                 options->prefix_length = 0;
3265
3266         if (options->output_format & (DIFF_FORMAT_NAME |
3267                                       DIFF_FORMAT_NAME_STATUS |
3268                                       DIFF_FORMAT_CHECKDIFF |
3269                                       DIFF_FORMAT_NO_OUTPUT))
3270                 options->output_format &= ~(DIFF_FORMAT_RAW |
3271                                             DIFF_FORMAT_NUMSTAT |
3272                                             DIFF_FORMAT_DIFFSTAT |
3273                                             DIFF_FORMAT_SHORTSTAT |
3274                                             DIFF_FORMAT_DIRSTAT |
3275                                             DIFF_FORMAT_SUMMARY |
3276                                             DIFF_FORMAT_PATCH);
3277
3278         /*
3279          * These cases always need recursive; we do not drop caller-supplied
3280          * recursive bits for other formats here.
3281          */
3282         if (options->output_format & (DIFF_FORMAT_PATCH |
3283                                       DIFF_FORMAT_NUMSTAT |
3284                                       DIFF_FORMAT_DIFFSTAT |
3285                                       DIFF_FORMAT_SHORTSTAT |
3286                                       DIFF_FORMAT_DIRSTAT |
3287                                       DIFF_FORMAT_SUMMARY |
3288                                       DIFF_FORMAT_CHECKDIFF))
3289                 DIFF_OPT_SET(options, RECURSIVE);
3290         /*
3291          * Also pickaxe would not work very well if you do not say recursive
3292          */
3293         if (options->pickaxe)
3294                 DIFF_OPT_SET(options, RECURSIVE);
3295         /*
3296          * When patches are generated, submodules diffed against the work tree
3297          * must be checked for dirtiness too so it can be shown in the output
3298          */
3299         if (options->output_format & DIFF_FORMAT_PATCH)
3300                 DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3301
3302         if (options->detect_rename && options->rename_limit < 0)
3303                 options->rename_limit = diff_rename_limit_default;
3304         if (options->setup & DIFF_SETUP_USE_CACHE) {
3305                 if (!active_cache)
3306                         /* read-cache does not die even when it fails
3307                          * so it is safe for us to do this here.  Also
3308                          * it does not smudge active_cache or active_nr
3309                          * when it fails, so we do not have to worry about
3310                          * cleaning it up ourselves either.
3311                          */
3312                         read_cache();
3313         }
3314         if (options->abbrev <= 0 || 40 < options->abbrev)
3315                 options->abbrev = 40; /* full */
3316
3317         /*
3318          * It does not make sense to show the first hit we happened
3319          * to have found.  It does not make sense not to return with
3320          * exit code in such a case either.
3321          */
3322         if (DIFF_OPT_TST(options, QUICK)) {
3323                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
3324                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3325         }
3326 }
3327
3328 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3329 {
3330         char c, *eq;
3331         int len;
3332
3333         if (*arg != '-')
3334                 return 0;
3335         c = *++arg;
3336         if (!c)
3337                 return 0;
3338         if (c == arg_short) {
3339                 c = *++arg;
3340                 if (!c)
3341                         return 1;
3342                 if (val && isdigit(c)) {
3343                         char *end;
3344                         int n = strtoul(arg, &end, 10);
3345                         if (*end)
3346                                 return 0;
3347                         *val = n;
3348                         return 1;
3349                 }
3350                 return 0;
3351         }
3352         if (c != '-')
3353                 return 0;
3354         arg++;
3355         eq = strchr(arg, '=');
3356         if (eq)
3357                 len = eq - arg;
3358         else
3359                 len = strlen(arg);
3360         if (!len || strncmp(arg, arg_long, len))
3361                 return 0;
3362         if (eq) {
3363                 int n;
3364                 char *end;
3365                 if (!isdigit(*++eq))
3366                         return 0;
3367                 n = strtoul(eq, &end, 10);
3368                 if (*end)
3369                         return 0;
3370                 *val = n;
3371         }
3372         return 1;
3373 }
3374
3375 static int diff_scoreopt_parse(const char *opt);
3376
3377 static inline int short_opt(char opt, const char **argv,
3378                             const char **optarg)
3379 {
3380         const char *arg = argv[0];
3381         if (arg[0] != '-' || arg[1] != opt)
3382                 return 0;
3383         if (arg[2] != '\0') {
3384                 *optarg = arg + 2;
3385                 return 1;
3386         }
3387         if (!argv[1])
3388                 die("Option '%c' requires a value", opt);
3389         *optarg = argv[1];
3390         return 2;
3391 }
3392
3393 int parse_long_opt(const char *opt, const char **argv,
3394                    const char **optarg)
3395 {
3396         const char *arg = argv[0];
3397         if (arg[0] != '-' || arg[1] != '-')
3398                 return 0;
3399         arg += strlen("--");
3400         if (prefixcmp(arg, opt))
3401                 return 0;
3402         arg += strlen(opt);
3403         if (*arg == '=') { /* sticked form: --option=value */
3404                 *optarg = arg + 1;
3405                 return 1;
3406         }
3407         if (*arg != '\0')
3408                 return 0;
3409         /* separate form: --option value */
3410         if (!argv[1])
3411                 die("Option '--%s' requires a value", opt);
3412         *optarg = argv[1];
3413         return 2;
3414 }
3415
3416 static int stat_opt(struct diff_options *options, const char **av)
3417 {
3418         const char *arg = av[0];
3419         char *end;
3420         int width = options->stat_width;
3421         int name_width = options->stat_name_width;
3422         int graph_width = options->stat_graph_width;
3423         int count = options->stat_count;
3424         int argcount = 1;
3425
3426         arg += strlen("--stat");
3427         end = (char *)arg;
3428
3429         switch (*arg) {
3430         case '-':
3431                 if (!prefixcmp(arg, "-width")) {
3432                         arg += strlen("-width");
3433                         if (*arg == '=')
3434                                 width = strtoul(arg + 1, &end, 10);
3435                         else if (!*arg && !av[1])
3436                                 die("Option '--stat-width' requires a value");
3437                         else if (!*arg) {
3438                                 width = strtoul(av[1], &end, 10);
3439                                 argcount = 2;
3440                         }
3441                 } else if (!prefixcmp(arg, "-name-width")) {
3442                         arg += strlen("-name-width");
3443                         if (*arg == '=')
3444                                 name_width = strtoul(arg + 1, &end, 10);
3445                         else if (!*arg && !av[1])
3446                                 die("Option '--stat-name-width' requires a value");
3447                         else if (!*arg) {
3448                                 name_width = strtoul(av[1], &end, 10);
3449                                 argcount = 2;
3450                         }
3451                 } else if (!prefixcmp(arg, "-graph-width")) {
3452                         arg += strlen("-graph-width");
3453                         if (*arg == '=')
3454                                 graph_width = strtoul(arg + 1, &end, 10);
3455                         else if (!*arg && !av[1])
3456                                 die("Option '--stat-graph-width' requires a value");
3457                         else if (!*arg) {
3458                                 graph_width = strtoul(av[1], &end, 10);
3459                                 argcount = 2;
3460                         }
3461                 } else if (!prefixcmp(arg, "-count")) {
3462                         arg += strlen("-count");
3463                         if (*arg == '=')
3464                                 count = strtoul(arg + 1, &end, 10);
3465                         else if (!*arg && !av[1])
3466                                 die("Option '--stat-count' requires a value");
3467                         else if (!*arg) {
3468                                 count = strtoul(av[1], &end, 10);
3469                                 argcount = 2;
3470                         }
3471                 }
3472                 break;
3473         case '=':
3474                 width = strtoul(arg+1, &end, 10);
3475                 if (*end == ',')
3476                         name_width = strtoul(end+1, &end, 10);
3477                 if (*end == ',')
3478                         count = strtoul(end+1, &end, 10);
3479         }
3480
3481         /* Important! This checks all the error cases! */
3482         if (*end)
3483                 return 0;
3484         options->output_format |= DIFF_FORMAT_DIFFSTAT;
3485         options->stat_name_width = name_width;
3486         options->stat_graph_width = graph_width;
3487         options->stat_width = width;
3488         options->stat_count = count;
3489         return argcount;
3490 }
3491
3492 static int parse_dirstat_opt(struct diff_options *options, const char *params)
3493 {
3494         struct strbuf errmsg = STRBUF_INIT;
3495         if (parse_dirstat_params(options, params, &errmsg))
3496                 die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3497                     errmsg.buf);
3498         strbuf_release(&errmsg);
3499         /*
3500          * The caller knows a dirstat-related option is given from the command
3501          * line; allow it to say "return this_function();"
3502          */
3503         options->output_format |= DIFF_FORMAT_DIRSTAT;
3504         return 1;
3505 }
3506
3507 static int parse_submodule_opt(struct diff_options *options, const char *value)
3508 {
3509         if (parse_submodule_params(options, value))
3510                 die(_("Failed to parse --submodule option parameter: '%s'"),
3511                         value);
3512         return 1;
3513 }
3514
3515 int diff_opt_parse(struct diff_options *options, const char **av, int ac)
3516 {
3517         const char *arg = av[0];
3518         const char *optarg;
3519         int argcount;
3520
3521         /* Output format options */
3522         if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch"))
3523                 options->output_format |= DIFF_FORMAT_PATCH;
3524         else if (opt_arg(arg, 'U', "unified", &options->context))
3525                 options->output_format |= DIFF_FORMAT_PATCH;
3526         else if (!strcmp(arg, "--raw"))
3527                 options->output_format |= DIFF_FORMAT_RAW;
3528         else if (!strcmp(arg, "--patch-with-raw"))
3529                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW;
3530         else if (!strcmp(arg, "--numstat"))
3531                 options->output_format |= DIFF_FORMAT_NUMSTAT;
3532         else if (!strcmp(arg, "--shortstat"))
3533                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
3534         else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3535                 return parse_dirstat_opt(options, "");
3536         else if (!prefixcmp(arg, "-X"))
3537                 return parse_dirstat_opt(options, arg + 2);
3538         else if (!prefixcmp(arg, "--dirstat="))
3539                 return parse_dirstat_opt(options, arg + 10);
3540         else if (!strcmp(arg, "--cumulative"))
3541                 return parse_dirstat_opt(options, "cumulative");
3542         else if (!strcmp(arg, "--dirstat-by-file"))
3543                 return parse_dirstat_opt(options, "files");
3544         else if (!prefixcmp(arg, "--dirstat-by-file=")) {
3545                 parse_dirstat_opt(options, "files");
3546                 return parse_dirstat_opt(options, arg + 18);
3547         }
3548         else if (!strcmp(arg, "--check"))
3549                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
3550         else if (!strcmp(arg, "--summary"))
3551                 options->output_format |= DIFF_FORMAT_SUMMARY;
3552         else if (!strcmp(arg, "--patch-with-stat"))
3553                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT;
3554         else if (!strcmp(arg, "--name-only"))
3555                 options->output_format |= DIFF_FORMAT_NAME;
3556         else if (!strcmp(arg, "--name-status"))
3557                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
3558         else if (!strcmp(arg, "-s"))
3559                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3560         else if (!prefixcmp(arg, "--stat"))
3561                 /* --stat, --stat-width, --stat-name-width, or --stat-count */
3562                 return stat_opt(options, av);
3563
3564         /* renames options */
3565         else if (!prefixcmp(arg, "-B") || !prefixcmp(arg, "--break-rewrites=") ||
3566                  !strcmp(arg, "--break-rewrites")) {
3567                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3568                         return error("invalid argument to -B: %s", arg+2);
3569         }
3570         else if (!prefixcmp(arg, "-M") || !prefixcmp(arg, "--find-renames=") ||
3571                  !strcmp(arg, "--find-renames")) {
3572                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3573                         return error("invalid argument to -M: %s", arg+2);
3574                 options->detect_rename = DIFF_DETECT_RENAME;
3575         }
3576         else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3577                 options->irreversible_delete = 1;
3578         }
3579         else if (!prefixcmp(arg, "-C") || !prefixcmp(arg, "--find-copies=") ||
3580                  !strcmp(arg, "--find-copies")) {
3581                 if (options->detect_rename == DIFF_DETECT_COPY)
3582                         DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3583                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3584                         return error("invalid argument to -C: %s", arg+2);
3585                 options->detect_rename = DIFF_DETECT_COPY;
3586         }
3587         else if (!strcmp(arg, "--no-renames"))
3588                 options->detect_rename = 0;
3589         else if (!strcmp(arg, "--rename-empty"))
3590                 DIFF_OPT_SET(options, RENAME_EMPTY);
3591         else if (!strcmp(arg, "--no-rename-empty"))
3592                 DIFF_OPT_CLR(options, RENAME_EMPTY);
3593         else if (!strcmp(arg, "--relative"))
3594                 DIFF_OPT_SET(options, RELATIVE_NAME);
3595         else if (!prefixcmp(arg, "--relative=")) {
3596                 DIFF_OPT_SET(options, RELATIVE_NAME);
3597                 options->prefix = arg + 11;
3598         }
3599
3600         /* xdiff options */
3601         else if (!strcmp(arg, "--minimal"))
3602                 DIFF_XDL_SET(options, NEED_MINIMAL);
3603         else if (!strcmp(arg, "--no-minimal"))
3604                 DIFF_XDL_CLR(options, NEED_MINIMAL);
3605         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3606                 DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3607         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3608                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3609         else if (!strcmp(arg, "--ignore-space-at-eol"))
3610                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3611         else if (!strcmp(arg, "--patience"))
3612                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3613         else if (!strcmp(arg, "--histogram"))
3614                 options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3615
3616         /* flags options */
3617         else if (!strcmp(arg, "--binary")) {
3618                 options->output_format |= DIFF_FORMAT_PATCH;
3619                 DIFF_OPT_SET(options, BINARY);
3620         }
3621         else if (!strcmp(arg, "--full-index"))
3622                 DIFF_OPT_SET(options, FULL_INDEX);
3623         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3624                 DIFF_OPT_SET(options, TEXT);
3625         else if (!strcmp(arg, "-R"))
3626                 DIFF_OPT_SET(options, REVERSE_DIFF);
3627         else if (!strcmp(arg, "--find-copies-harder"))
3628                 DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3629         else if (!strcmp(arg, "--follow"))
3630                 DIFF_OPT_SET(options, FOLLOW_RENAMES);
3631         else if (!strcmp(arg, "--color"))
3632                 options->use_color = 1;
3633         else if (!prefixcmp(arg, "--color=")) {
3634                 int value = git_config_colorbool(NULL, arg+8);
3635                 if (value < 0)
3636                         return error("option `color' expects \"always\", \"auto\", or \"never\"");
3637                 options->use_color = value;
3638         }
3639         else if (!strcmp(arg, "--no-color"))
3640                 options->use_color = 0;
3641         else if (!strcmp(arg, "--color-words")) {
3642                 options->use_color = 1;
3643                 options->word_diff = DIFF_WORDS_COLOR;
3644         }
3645         else if (!prefixcmp(arg, "--color-words=")) {
3646                 options->use_color = 1;
3647                 options->word_diff = DIFF_WORDS_COLOR;
3648                 options->word_regex = arg + 14;
3649         }
3650         else if (!strcmp(arg, "--word-diff")) {
3651                 if (options->word_diff == DIFF_WORDS_NONE)
3652                         options->word_diff = DIFF_WORDS_PLAIN;
3653         }
3654         else if (!prefixcmp(arg, "--word-diff=")) {
3655                 const char *type = arg + 12;
3656                 if (!strcmp(type, "plain"))
3657                         options->word_diff = DIFF_WORDS_PLAIN;
3658                 else if (!strcmp(type, "color")) {
3659                         options->use_color = 1;
3660                         options->word_diff = DIFF_WORDS_COLOR;
3661                 }
3662                 else if (!strcmp(type, "porcelain"))
3663                         options->word_diff = DIFF_WORDS_PORCELAIN;
3664                 else if (!strcmp(type, "none"))
3665                         options->word_diff = DIFF_WORDS_NONE;
3666                 else
3667                         die("bad --word-diff argument: %s", type);
3668         }
3669         else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3670                 if (options->word_diff == DIFF_WORDS_NONE)
3671                         options->word_diff = DIFF_WORDS_PLAIN;
3672                 options->word_regex = optarg;
3673                 return argcount;
3674         }
3675         else if (!strcmp(arg, "--exit-code"))
3676                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3677         else if (!strcmp(arg, "--quiet"))
3678                 DIFF_OPT_SET(options, QUICK);
3679         else if (!strcmp(arg, "--ext-diff"))
3680                 DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3681         else if (!strcmp(arg, "--no-ext-diff"))
3682                 DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3683         else if (!strcmp(arg, "--textconv"))
3684                 DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3685         else if (!strcmp(arg, "--no-textconv"))
3686                 DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3687         else if (!strcmp(arg, "--ignore-submodules")) {
3688                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3689                 handle_ignore_submodules_arg(options, "all");
3690         } else if (!prefixcmp(arg, "--ignore-submodules=")) {
3691                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3692                 handle_ignore_submodules_arg(options, arg + 20);
3693         } else if (!strcmp(arg, "--submodule"))
3694                 DIFF_OPT_SET(options, SUBMODULE_LOG);
3695         else if (!prefixcmp(arg, "--submodule="))
3696                 return parse_submodule_opt(options, arg + 12);
3697
3698         /* misc options */
3699         else if (!strcmp(arg, "-z"))
3700                 options->line_termination = 0;
3701         else if ((argcount = short_opt('l', av, &optarg))) {
3702                 options->rename_limit = strtoul(optarg, NULL, 10);
3703                 return argcount;
3704         }
3705         else if ((argcount = short_opt('S', av, &optarg))) {
3706                 options->pickaxe = optarg;
3707                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3708                 return argcount;
3709         } else if ((argcount = short_opt('G', av, &optarg))) {
3710                 options->pickaxe = optarg;
3711                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3712                 return argcount;
3713         }
3714         else if (!strcmp(arg, "--pickaxe-all"))
3715                 options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3716         else if (!strcmp(arg, "--pickaxe-regex"))
3717                 options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3718         else if ((argcount = short_opt('O', av, &optarg))) {
3719                 options->orderfile = optarg;
3720                 return argcount;
3721         }
3722         else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3723                 options->filter = optarg;
3724                 return argcount;
3725         }
3726         else if (!strcmp(arg, "--abbrev"))
3727                 options->abbrev = DEFAULT_ABBREV;
3728         else if (!prefixcmp(arg, "--abbrev=")) {
3729                 options->abbrev = strtoul(arg + 9, NULL, 10);
3730                 if (options->abbrev < MINIMUM_ABBREV)
3731                         options->abbrev = MINIMUM_ABBREV;
3732                 else if (40 < options->abbrev)
3733                         options->abbrev = 40;
3734         }
3735         else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3736                 options->a_prefix = optarg;
3737                 return argcount;
3738         }
3739         else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3740                 options->b_prefix = optarg;
3741                 return argcount;
3742         }
3743         else if (!strcmp(arg, "--no-prefix"))
3744                 options->a_prefix = options->b_prefix = "";
3745         else if (opt_arg(arg, '\0', "inter-hunk-context",
3746                          &options->interhunkcontext))
3747                 ;
3748         else if (!strcmp(arg, "-W"))
3749                 DIFF_OPT_SET(options, FUNCCONTEXT);
3750         else if (!strcmp(arg, "--function-context"))
3751                 DIFF_OPT_SET(options, FUNCCONTEXT);
3752         else if (!strcmp(arg, "--no-function-context"))
3753                 DIFF_OPT_CLR(options, FUNCCONTEXT);
3754         else if ((argcount = parse_long_opt("output", av, &optarg))) {
3755                 options->file = fopen(optarg, "w");
3756                 if (!options->file)
3757                         die_errno("Could not open '%s'", optarg);
3758                 options->close_file = 1;
3759                 return argcount;
3760         } else
3761                 return 0;
3762         return 1;
3763 }
3764
3765 int parse_rename_score(const char **cp_p)
3766 {
3767         unsigned long num, scale;
3768         int ch, dot;
3769         const char *cp = *cp_p;
3770
3771         num = 0;
3772         scale = 1;
3773         dot = 0;
3774         for (;;) {
3775                 ch = *cp;
3776                 if ( !dot && ch == '.' ) {
3777                         scale = 1;
3778                         dot = 1;
3779                 } else if ( ch == '%' ) {
3780                         scale = dot ? scale*100 : 100;
3781                         cp++;   /* % is always at the end */
3782                         break;
3783                 } else if ( ch >= '0' && ch <= '9' ) {
3784                         if ( scale < 100000 ) {
3785                                 scale *= 10;
3786                                 num = (num*10) + (ch-'0');
3787                         }
3788                 } else {
3789                         break;
3790                 }
3791                 cp++;
3792         }
3793         *cp_p = cp;
3794
3795         /* user says num divided by scale and we say internally that
3796          * is MAX_SCORE * num / scale.
3797          */
3798         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
3799 }
3800
3801 static int diff_scoreopt_parse(const char *opt)
3802 {
3803         int opt1, opt2, cmd;
3804
3805         if (*opt++ != '-')
3806                 return -1;
3807         cmd = *opt++;
3808         if (cmd == '-') {
3809                 /* convert the long-form arguments into short-form versions */
3810                 if (!prefixcmp(opt, "break-rewrites")) {
3811                         opt += strlen("break-rewrites");
3812                         if (*opt == 0 || *opt++ == '=')
3813                                 cmd = 'B';
3814                 } else if (!prefixcmp(opt, "find-copies")) {
3815                         opt += strlen("find-copies");
3816                         if (*opt == 0 || *opt++ == '=')
3817                                 cmd = 'C';
3818                 } else if (!prefixcmp(opt, "find-renames")) {
3819                         opt += strlen("find-renames");
3820                         if (*opt == 0 || *opt++ == '=')
3821                                 cmd = 'M';
3822                 }
3823         }
3824         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
3825                 return -1; /* that is not a -M, -C nor -B option */
3826
3827         opt1 = parse_rename_score(&opt);
3828         if (cmd != 'B')
3829                 opt2 = 0;
3830         else {
3831                 if (*opt == 0)
3832                         opt2 = 0;
3833                 else if (*opt != '/')
3834                         return -1; /* we expect -B80/99 or -B80 */
3835                 else {
3836                         opt++;
3837                         opt2 = parse_rename_score(&opt);
3838                 }
3839         }
3840         if (*opt != 0)
3841                 return -1;
3842         return opt1 | (opt2 << 16);
3843 }
3844
3845 struct diff_queue_struct diff_queued_diff;
3846
3847 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
3848 {
3849         if (queue->alloc <= queue->nr) {
3850                 queue->alloc = alloc_nr(queue->alloc);
3851                 queue->queue = xrealloc(queue->queue,
3852                                         sizeof(dp) * queue->alloc);
3853         }
3854         queue->queue[queue->nr++] = dp;
3855 }
3856
3857 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
3858                                  struct diff_filespec *one,
3859                                  struct diff_filespec *two)
3860 {
3861         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
3862         dp->one = one;
3863         dp->two = two;
3864         if (queue)
3865                 diff_q(queue, dp);
3866         return dp;
3867 }
3868
3869 void diff_free_filepair(struct diff_filepair *p)
3870 {
3871         free_filespec(p->one);
3872         free_filespec(p->two);
3873         free(p);
3874 }
3875
3876 /* This is different from find_unique_abbrev() in that
3877  * it stuffs the result with dots for alignment.
3878  */
3879 const char *diff_unique_abbrev(const unsigned char *sha1, int len)
3880 {
3881         int abblen;
3882         const char *abbrev;
3883         if (len == 40)
3884                 return sha1_to_hex(sha1);
3885
3886         abbrev = find_unique_abbrev(sha1, len);
3887         abblen = strlen(abbrev);
3888         if (abblen < 37) {
3889                 static char hex[41];
3890                 if (len < abblen && abblen <= len + 2)
3891                         sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
3892                 else
3893                         sprintf(hex, "%s...", abbrev);
3894                 return hex;
3895         }
3896         return sha1_to_hex(sha1);
3897 }
3898
3899 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
3900 {
3901         int line_termination = opt->line_termination;
3902         int inter_name_termination = line_termination ? '\t' : '\0';
3903         if (opt->output_prefix) {
3904                 struct strbuf *msg = NULL;
3905                 msg = opt->output_prefix(opt, opt->output_prefix_data);
3906                 fprintf(opt->file, "%s", msg->buf);
3907         }
3908
3909         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
3910                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
3911                         diff_unique_abbrev(p->one->sha1, opt->abbrev));
3912                 fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
3913         }
3914         if (p->score) {
3915                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
3916                         inter_name_termination);
3917         } else {
3918                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
3919         }
3920
3921         if (p->status == DIFF_STATUS_COPIED ||
3922             p->status == DIFF_STATUS_RENAMED) {
3923                 const char *name_a, *name_b;
3924                 name_a = p->one->path;
3925                 name_b = p->two->path;
3926                 strip_prefix(opt->prefix_length, &name_a, &name_b);
3927                 write_name_quoted(name_a, opt->file, inter_name_termination);
3928                 write_name_quoted(name_b, opt->file, line_termination);
3929         } else {
3930                 const char *name_a, *name_b;
3931                 name_a = p->one->mode ? p->one->path : p->two->path;
3932                 name_b = NULL;
3933                 strip_prefix(opt->prefix_length, &name_a, &name_b);
3934                 write_name_quoted(name_a, opt->file, line_termination);
3935         }
3936 }
3937
3938 int diff_unmodified_pair(struct diff_filepair *p)
3939 {
3940         /* This function is written stricter than necessary to support
3941          * the currently implemented transformers, but the idea is to
3942          * let transformers to produce diff_filepairs any way they want,
3943          * and filter and clean them up here before producing the output.
3944          */
3945         struct diff_filespec *one = p->one, *two = p->two;
3946
3947         if (DIFF_PAIR_UNMERGED(p))
3948                 return 0; /* unmerged is interesting */
3949
3950         /* deletion, addition, mode or type change
3951          * and rename are all interesting.
3952          */
3953         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
3954             DIFF_PAIR_MODE_CHANGED(p) ||
3955             strcmp(one->path, two->path))
3956                 return 0;
3957
3958         /* both are valid and point at the same path.  that is, we are
3959          * dealing with a change.
3960          */
3961         if (one->sha1_valid && two->sha1_valid &&
3962             !hashcmp(one->sha1, two->sha1) &&
3963             !one->dirty_submodule && !two->dirty_submodule)
3964                 return 1; /* no change */
3965         if (!one->sha1_valid && !two->sha1_valid)
3966                 return 1; /* both look at the same file on the filesystem. */
3967         return 0;
3968 }
3969
3970 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
3971 {
3972         if (diff_unmodified_pair(p))
3973                 return;
3974
3975         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3976             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3977                 return; /* no tree diffs in patch format */
3978
3979         run_diff(p, o);
3980 }
3981
3982 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
3983                             struct diffstat_t *diffstat)
3984 {
3985         if (diff_unmodified_pair(p))
3986                 return;
3987
3988         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3989             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3990                 return; /* no useful stat for tree diffs */
3991
3992         run_diffstat(p, o, diffstat);
3993 }
3994
3995 static void diff_flush_checkdiff(struct diff_filepair *p,
3996                 struct diff_options *o)
3997 {
3998         if (diff_unmodified_pair(p))
3999                 return;
4000
4001         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4002             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4003                 return; /* nothing to check in tree diffs */
4004
4005         run_checkdiff(p, o);
4006 }
4007
4008 int diff_queue_is_empty(void)
4009 {
4010         struct diff_queue_struct *q = &diff_queued_diff;
4011         int i;
4012         for (i = 0; i < q->nr; i++)
4013                 if (!diff_unmodified_pair(q->queue[i]))
4014                         return 0;
4015         return 1;
4016 }
4017
4018 #if DIFF_DEBUG
4019 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4020 {
4021         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4022                 x, one ? one : "",
4023                 s->path,
4024                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
4025                 s->mode,
4026                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
4027         fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
4028                 x, one ? one : "",
4029                 s->size, s->xfrm_flags);
4030 }
4031
4032 void diff_debug_filepair(const struct diff_filepair *p, int i)
4033 {
4034         diff_debug_filespec(p->one, i, "one");
4035         diff_debug_filespec(p->two, i, "two");
4036         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4037                 p->score, p->status ? p->status : '?',
4038                 p->one->rename_used, p->broken_pair);
4039 }
4040
4041 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4042 {
4043         int i;
4044         if (msg)
4045                 fprintf(stderr, "%s\n", msg);
4046         fprintf(stderr, "q->nr = %d\n", q->nr);
4047         for (i = 0; i < q->nr; i++) {
4048                 struct diff_filepair *p = q->queue[i];
4049                 diff_debug_filepair(p, i);
4050         }
4051 }
4052 #endif
4053
4054 static void diff_resolve_rename_copy(void)
4055 {
4056         int i;
4057         struct diff_filepair *p;
4058         struct diff_queue_struct *q = &diff_queued_diff;
4059
4060         diff_debug_queue("resolve-rename-copy", q);
4061
4062         for (i = 0; i < q->nr; i++) {
4063                 p = q->queue[i];
4064                 p->status = 0; /* undecided */
4065                 if (DIFF_PAIR_UNMERGED(p))
4066                         p->status = DIFF_STATUS_UNMERGED;
4067                 else if (!DIFF_FILE_VALID(p->one))
4068                         p->status = DIFF_STATUS_ADDED;
4069                 else if (!DIFF_FILE_VALID(p->two))
4070                         p->status = DIFF_STATUS_DELETED;
4071                 else if (DIFF_PAIR_TYPE_CHANGED(p))
4072                         p->status = DIFF_STATUS_TYPE_CHANGED;
4073
4074                 /* from this point on, we are dealing with a pair
4075                  * whose both sides are valid and of the same type, i.e.
4076                  * either in-place edit or rename/copy edit.
4077                  */
4078                 else if (DIFF_PAIR_RENAME(p)) {
4079                         /*
4080                          * A rename might have re-connected a broken
4081                          * pair up, causing the pathnames to be the
4082                          * same again. If so, that's not a rename at
4083                          * all, just a modification..
4084                          *
4085                          * Otherwise, see if this source was used for
4086                          * multiple renames, in which case we decrement
4087                          * the count, and call it a copy.
4088                          */
4089                         if (!strcmp(p->one->path, p->two->path))
4090                                 p->status = DIFF_STATUS_MODIFIED;
4091                         else if (--p->one->rename_used > 0)
4092                                 p->status = DIFF_STATUS_COPIED;
4093                         else
4094                                 p->status = DIFF_STATUS_RENAMED;
4095                 }
4096                 else if (hashcmp(p->one->sha1, p->two->sha1) ||
4097                          p->one->mode != p->two->mode ||
4098                          p->one->dirty_submodule ||
4099                          p->two->dirty_submodule ||
4100                          is_null_sha1(p->one->sha1))
4101                         p->status = DIFF_STATUS_MODIFIED;
4102                 else {
4103                         /* This is a "no-change" entry and should not
4104                          * happen anymore, but prepare for broken callers.
4105                          */
4106                         error("feeding unmodified %s to diffcore",
4107                               p->one->path);
4108                         p->status = DIFF_STATUS_UNKNOWN;
4109                 }
4110         }
4111         diff_debug_queue("resolve-rename-copy done", q);
4112 }
4113
4114 static int check_pair_status(struct diff_filepair *p)
4115 {
4116         switch (p->status) {
4117         case DIFF_STATUS_UNKNOWN:
4118                 return 0;
4119         case 0:
4120                 die("internal error in diff-resolve-rename-copy");
4121         default:
4122                 return 1;
4123         }
4124 }
4125
4126 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4127 {
4128         int fmt = opt->output_format;
4129
4130         if (fmt & DIFF_FORMAT_CHECKDIFF)
4131                 diff_flush_checkdiff(p, opt);
4132         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4133                 diff_flush_raw(p, opt);
4134         else if (fmt & DIFF_FORMAT_NAME) {
4135                 const char *name_a, *name_b;
4136                 name_a = p->two->path;
4137                 name_b = NULL;
4138                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4139                 write_name_quoted(name_a, opt->file, opt->line_termination);
4140         }
4141 }
4142
4143 static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4144 {
4145         if (fs->mode)
4146                 fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4147         else
4148                 fprintf(file, " %s ", newdelete);
4149         write_name_quoted(fs->path, file, '\n');
4150 }
4151
4152
4153 static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4154                 const char *line_prefix)
4155 {
4156         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4157                 fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4158                         p->two->mode, show_name ? ' ' : '\n');
4159                 if (show_name) {
4160                         write_name_quoted(p->two->path, file, '\n');
4161                 }
4162         }
4163 }
4164
4165 static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4166                         const char *line_prefix)
4167 {
4168         char *names = pprint_rename(p->one->path, p->two->path);
4169
4170         fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4171         free(names);
4172         show_mode_change(file, p, 0, line_prefix);
4173 }
4174
4175 static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4176 {
4177         FILE *file = opt->file;
4178         char *line_prefix = "";
4179
4180         if (opt->output_prefix) {
4181                 struct strbuf *buf = opt->output_prefix(opt, opt->output_prefix_data);
4182                 line_prefix = buf->buf;
4183         }
4184
4185         switch(p->status) {
4186         case DIFF_STATUS_DELETED:
4187                 fputs(line_prefix, file);
4188                 show_file_mode_name(file, "delete", p->one);
4189                 break;
4190         case DIFF_STATUS_ADDED:
4191                 fputs(line_prefix, file);
4192                 show_file_mode_name(file, "create", p->two);
4193                 break;
4194         case DIFF_STATUS_COPIED:
4195                 fputs(line_prefix, file);
4196                 show_rename_copy(file, "copy", p, line_prefix);
4197                 break;
4198         case DIFF_STATUS_RENAMED:
4199                 fputs(line_prefix, file);
4200                 show_rename_copy(file, "rename", p, line_prefix);
4201                 break;
4202         default:
4203                 if (p->score) {
4204                         fprintf(file, "%s rewrite ", line_prefix);
4205                         write_name_quoted(p->two->path, file, ' ');
4206                         fprintf(file, "(%d%%)\n", similarity_index(p));
4207                 }
4208                 show_mode_change(file, p, !p->score, line_prefix);
4209                 break;
4210         }
4211 }
4212
4213 struct patch_id_t {
4214         git_SHA_CTX *ctx;
4215         int patchlen;
4216 };
4217
4218 static int remove_space(char *line, int len)
4219 {
4220         int i;
4221         char *dst = line;
4222         unsigned char c;
4223
4224         for (i = 0; i < len; i++)
4225                 if (!isspace((c = line[i])))
4226                         *dst++ = c;
4227
4228         return dst - line;
4229 }
4230
4231 static void patch_id_consume(void *priv, char *line, unsigned long len)
4232 {
4233         struct patch_id_t *data = priv;
4234         int new_len;
4235
4236         /* Ignore line numbers when computing the SHA1 of the patch */
4237         if (!prefixcmp(line, "@@ -"))
4238                 return;
4239
4240         new_len = remove_space(line, len);
4241
4242         git_SHA1_Update(data->ctx, line, new_len);
4243         data->patchlen += new_len;
4244 }
4245
4246 /* returns 0 upon success, and writes result into sha1 */
4247 static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
4248 {
4249         struct diff_queue_struct *q = &diff_queued_diff;
4250         int i;
4251         git_SHA_CTX ctx;
4252         struct patch_id_t data;
4253         char buffer[PATH_MAX * 4 + 20];
4254
4255         git_SHA1_Init(&ctx);
4256         memset(&data, 0, sizeof(struct patch_id_t));
4257         data.ctx = &ctx;
4258
4259         for (i = 0; i < q->nr; i++) {
4260                 xpparam_t xpp;
4261                 xdemitconf_t xecfg;
4262                 mmfile_t mf1, mf2;
4263                 struct diff_filepair *p = q->queue[i];
4264                 int len1, len2;
4265
4266                 memset(&xpp, 0, sizeof(xpp));
4267                 memset(&xecfg, 0, sizeof(xecfg));
4268                 if (p->status == 0)
4269                         return error("internal diff status error");
4270                 if (p->status == DIFF_STATUS_UNKNOWN)
4271                         continue;
4272                 if (diff_unmodified_pair(p))
4273                         continue;
4274                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4275                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4276                         continue;
4277                 if (DIFF_PAIR_UNMERGED(p))
4278                         continue;
4279
4280                 diff_fill_sha1_info(p->one);
4281                 diff_fill_sha1_info(p->two);
4282                 if (fill_mmfile(&mf1, p->one) < 0 ||
4283                                 fill_mmfile(&mf2, p->two) < 0)
4284                         return error("unable to read files to diff");
4285
4286                 len1 = remove_space(p->one->path, strlen(p->one->path));
4287                 len2 = remove_space(p->two->path, strlen(p->two->path));
4288                 if (p->one->mode == 0)
4289                         len1 = snprintf(buffer, sizeof(buffer),
4290                                         "diff--gita/%.*sb/%.*s"
4291                                         "newfilemode%06o"
4292                                         "---/dev/null"
4293                                         "+++b/%.*s",
4294                                         len1, p->one->path,
4295                                         len2, p->two->path,
4296                                         p->two->mode,
4297                                         len2, p->two->path);
4298                 else if (p->two->mode == 0)
4299                         len1 = snprintf(buffer, sizeof(buffer),
4300                                         "diff--gita/%.*sb/%.*s"
4301                                         "deletedfilemode%06o"
4302                                         "---a/%.*s"
4303                                         "+++/dev/null",
4304                                         len1, p->one->path,
4305                                         len2, p->two->path,
4306                                         p->one->mode,
4307                                         len1, p->one->path);
4308                 else
4309                         len1 = snprintf(buffer, sizeof(buffer),
4310                                         "diff--gita/%.*sb/%.*s"
4311                                         "---a/%.*s"
4312                                         "+++b/%.*s",
4313                                         len1, p->one->path,
4314                                         len2, p->two->path,
4315                                         len1, p->one->path,
4316                                         len2, p->two->path);
4317                 git_SHA1_Update(&ctx, buffer, len1);
4318
4319                 if (diff_filespec_is_binary(p->one) ||
4320                     diff_filespec_is_binary(p->two)) {
4321                         git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
4322                         git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
4323                         continue;
4324                 }
4325
4326                 xpp.flags = 0;
4327                 xecfg.ctxlen = 3;
4328                 xecfg.flags = 0;
4329                 xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4330                               &xpp, &xecfg);
4331         }
4332
4333         git_SHA1_Final(sha1, &ctx);
4334         return 0;
4335 }
4336
4337 int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
4338 {
4339         struct diff_queue_struct *q = &diff_queued_diff;
4340         int i;
4341         int result = diff_get_patch_id(options, sha1);
4342
4343         for (i = 0; i < q->nr; i++)
4344                 diff_free_filepair(q->queue[i]);
4345
4346         free(q->queue);
4347         DIFF_QUEUE_CLEAR(q);
4348
4349         return result;
4350 }
4351
4352 static int is_summary_empty(const struct diff_queue_struct *q)
4353 {
4354         int i;
4355
4356         for (i = 0; i < q->nr; i++) {
4357                 const struct diff_filepair *p = q->queue[i];
4358
4359                 switch (p->status) {
4360                 case DIFF_STATUS_DELETED:
4361                 case DIFF_STATUS_ADDED:
4362                 case DIFF_STATUS_COPIED:
4363                 case DIFF_STATUS_RENAMED:
4364                         return 0;
4365                 default:
4366                         if (p->score)
4367                                 return 0;
4368                         if (p->one->mode && p->two->mode &&
4369                             p->one->mode != p->two->mode)
4370                                 return 0;
4371                         break;
4372                 }
4373         }
4374         return 1;
4375 }
4376
4377 static const char rename_limit_warning[] =
4378 "inexact rename detection was skipped due to too many files.";
4379
4380 static const char degrade_cc_to_c_warning[] =
4381 "only found copies from modified paths due to too many files.";
4382
4383 static const char rename_limit_advice[] =
4384 "you may want to set your %s variable to at least "
4385 "%d and retry the command.";
4386
4387 void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4388 {
4389         if (degraded_cc)
4390                 warning(degrade_cc_to_c_warning);
4391         else if (needed)
4392                 warning(rename_limit_warning);
4393         else
4394                 return;
4395         if (0 < needed && needed < 32767)
4396                 warning(rename_limit_advice, varname, needed);
4397 }
4398
4399 void diff_flush(struct diff_options *options)
4400 {
4401         struct diff_queue_struct *q = &diff_queued_diff;
4402         int i, output_format = options->output_format;
4403         int separator = 0;
4404         int dirstat_by_line = 0;
4405
4406         /*
4407          * Order: raw, stat, summary, patch
4408          * or:    name/name-status/checkdiff (other bits clear)
4409          */
4410         if (!q->nr)
4411                 goto free_queue;
4412
4413         if (output_format & (DIFF_FORMAT_RAW |
4414                              DIFF_FORMAT_NAME |
4415                              DIFF_FORMAT_NAME_STATUS |
4416                              DIFF_FORMAT_CHECKDIFF)) {
4417                 for (i = 0; i < q->nr; i++) {
4418                         struct diff_filepair *p = q->queue[i];
4419                         if (check_pair_status(p))
4420                                 flush_one_pair(p, options);
4421                 }
4422                 separator++;
4423         }
4424
4425         if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4426                 dirstat_by_line = 1;
4427
4428         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4429             dirstat_by_line) {
4430                 struct diffstat_t diffstat;
4431
4432                 memset(&diffstat, 0, sizeof(struct diffstat_t));
4433                 for (i = 0; i < q->nr; i++) {
4434                         struct diff_filepair *p = q->queue[i];
4435                         if (check_pair_status(p))
4436                                 diff_flush_stat(p, options, &diffstat);
4437                 }
4438                 if (output_format & DIFF_FORMAT_NUMSTAT)
4439                         show_numstat(&diffstat, options);
4440                 if (output_format & DIFF_FORMAT_DIFFSTAT)
4441                         show_stats(&diffstat, options);
4442                 if (output_format & DIFF_FORMAT_SHORTSTAT)
4443                         show_shortstats(&diffstat, options);
4444                 if (output_format & DIFF_FORMAT_DIRSTAT)
4445                         show_dirstat_by_line(&diffstat, options);
4446                 free_diffstat_info(&diffstat);
4447                 separator++;
4448         }
4449         if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4450                 show_dirstat(options);
4451
4452         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4453                 for (i = 0; i < q->nr; i++) {
4454                         diff_summary(options, q->queue[i]);
4455                 }
4456                 separator++;
4457         }
4458
4459         if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4460             DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4461             DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4462                 /*
4463                  * run diff_flush_patch for the exit status. setting
4464                  * options->file to /dev/null should be safe, becaue we
4465                  * aren't supposed to produce any output anyway.
4466                  */
4467                 if (options->close_file)
4468                         fclose(options->file);
4469                 options->file = fopen("/dev/null", "w");
4470                 if (!options->file)
4471                         die_errno("Could not open /dev/null");
4472                 options->close_file = 1;
4473                 for (i = 0; i < q->nr; i++) {
4474                         struct diff_filepair *p = q->queue[i];
4475                         if (check_pair_status(p))
4476                                 diff_flush_patch(p, options);
4477                         if (options->found_changes)
4478                                 break;
4479                 }
4480         }
4481
4482         if (output_format & DIFF_FORMAT_PATCH) {
4483                 if (separator) {
4484                         if (options->output_prefix) {
4485                                 struct strbuf *msg = NULL;
4486                                 msg = options->output_prefix(options,
4487                                         options->output_prefix_data);
4488                                 fwrite(msg->buf, msg->len, 1, options->file);
4489                         }
4490                         putc(options->line_termination, options->file);
4491                         if (options->stat_sep) {
4492                                 /* attach patch instead of inline */
4493                                 fputs(options->stat_sep, options->file);
4494                         }
4495                 }
4496
4497                 for (i = 0; i < q->nr; i++) {
4498                         struct diff_filepair *p = q->queue[i];
4499                         if (check_pair_status(p))
4500                                 diff_flush_patch(p, options);
4501                 }
4502         }
4503
4504         if (output_format & DIFF_FORMAT_CALLBACK)
4505                 options->format_callback(q, options, options->format_callback_data);
4506
4507         for (i = 0; i < q->nr; i++)
4508                 diff_free_filepair(q->queue[i]);
4509 free_queue:
4510         free(q->queue);
4511         DIFF_QUEUE_CLEAR(q);
4512         if (options->close_file)
4513                 fclose(options->file);
4514
4515         /*
4516          * Report the content-level differences with HAS_CHANGES;
4517          * diff_addremove/diff_change does not set the bit when
4518          * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4519          */
4520         if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4521                 if (options->found_changes)
4522                         DIFF_OPT_SET(options, HAS_CHANGES);
4523                 else
4524                         DIFF_OPT_CLR(options, HAS_CHANGES);
4525         }
4526 }
4527
4528 static void diffcore_apply_filter(const char *filter)
4529 {
4530         int i;
4531         struct diff_queue_struct *q = &diff_queued_diff;
4532         struct diff_queue_struct outq;
4533         DIFF_QUEUE_CLEAR(&outq);
4534
4535         if (!filter)
4536                 return;
4537
4538         if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
4539                 int found;
4540                 for (i = found = 0; !found && i < q->nr; i++) {
4541                         struct diff_filepair *p = q->queue[i];
4542                         if (((p->status == DIFF_STATUS_MODIFIED) &&
4543                              ((p->score &&
4544                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4545                               (!p->score &&
4546                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4547                             ((p->status != DIFF_STATUS_MODIFIED) &&
4548                              strchr(filter, p->status)))
4549                                 found++;
4550                 }
4551                 if (found)
4552                         return;
4553
4554                 /* otherwise we will clear the whole queue
4555                  * by copying the empty outq at the end of this
4556                  * function, but first clear the current entries
4557                  * in the queue.
4558                  */
4559                 for (i = 0; i < q->nr; i++)
4560                         diff_free_filepair(q->queue[i]);
4561         }
4562         else {
4563                 /* Only the matching ones */
4564                 for (i = 0; i < q->nr; i++) {
4565                         struct diff_filepair *p = q->queue[i];
4566
4567                         if (((p->status == DIFF_STATUS_MODIFIED) &&
4568                              ((p->score &&
4569                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4570                               (!p->score &&
4571                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4572                             ((p->status != DIFF_STATUS_MODIFIED) &&
4573                              strchr(filter, p->status)))
4574                                 diff_q(&outq, p);
4575                         else
4576                                 diff_free_filepair(p);
4577                 }
4578         }
4579         free(q->queue);
4580         *q = outq;
4581 }
4582
4583 /* Check whether two filespecs with the same mode and size are identical */
4584 static int diff_filespec_is_identical(struct diff_filespec *one,
4585                                       struct diff_filespec *two)
4586 {
4587         if (S_ISGITLINK(one->mode))
4588                 return 0;
4589         if (diff_populate_filespec(one, 0))
4590                 return 0;
4591         if (diff_populate_filespec(two, 0))
4592                 return 0;
4593         return !memcmp(one->data, two->data, one->size);
4594 }
4595
4596 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4597 {
4598         int i;
4599         struct diff_queue_struct *q = &diff_queued_diff;
4600         struct diff_queue_struct outq;
4601         DIFF_QUEUE_CLEAR(&outq);
4602
4603         for (i = 0; i < q->nr; i++) {
4604                 struct diff_filepair *p = q->queue[i];
4605
4606                 /*
4607                  * 1. Entries that come from stat info dirtiness
4608                  *    always have both sides (iow, not create/delete),
4609                  *    one side of the object name is unknown, with
4610                  *    the same mode and size.  Keep the ones that
4611                  *    do not match these criteria.  They have real
4612                  *    differences.
4613                  *
4614                  * 2. At this point, the file is known to be modified,
4615                  *    with the same mode and size, and the object
4616                  *    name of one side is unknown.  Need to inspect
4617                  *    the identical contents.
4618                  */
4619                 if (!DIFF_FILE_VALID(p->one) || /* (1) */
4620                     !DIFF_FILE_VALID(p->two) ||
4621                     (p->one->sha1_valid && p->two->sha1_valid) ||
4622                     (p->one->mode != p->two->mode) ||
4623                     diff_populate_filespec(p->one, 1) ||
4624                     diff_populate_filespec(p->two, 1) ||
4625                     (p->one->size != p->two->size) ||
4626                     !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4627                         diff_q(&outq, p);
4628                 else {
4629                         /*
4630                          * The caller can subtract 1 from skip_stat_unmatch
4631                          * to determine how many paths were dirty only
4632                          * due to stat info mismatch.
4633                          */
4634                         if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4635                                 diffopt->skip_stat_unmatch++;
4636                         diff_free_filepair(p);
4637                 }
4638         }
4639         free(q->queue);
4640         *q = outq;
4641 }
4642
4643 static int diffnamecmp(const void *a_, const void *b_)
4644 {
4645         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4646         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4647         const char *name_a, *name_b;
4648
4649         name_a = a->one ? a->one->path : a->two->path;
4650         name_b = b->one ? b->one->path : b->two->path;
4651         return strcmp(name_a, name_b);
4652 }
4653
4654 void diffcore_fix_diff_index(struct diff_options *options)
4655 {
4656         struct diff_queue_struct *q = &diff_queued_diff;
4657         qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4658 }
4659
4660 void diffcore_std(struct diff_options *options)
4661 {
4662         if (options->skip_stat_unmatch)
4663                 diffcore_skip_stat_unmatch(options);
4664         if (!options->found_follow) {
4665                 /* See try_to_follow_renames() in tree-diff.c */
4666                 if (options->break_opt != -1)
4667                         diffcore_break(options->break_opt);
4668                 if (options->detect_rename)
4669                         diffcore_rename(options);
4670                 if (options->break_opt != -1)
4671                         diffcore_merge_broken();
4672         }
4673         if (options->pickaxe)
4674                 diffcore_pickaxe(options);
4675         if (options->orderfile)
4676                 diffcore_order(options->orderfile);
4677         if (!options->found_follow)
4678                 /* See try_to_follow_renames() in tree-diff.c */
4679                 diff_resolve_rename_copy();
4680         diffcore_apply_filter(options->filter);
4681
4682         if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4683                 DIFF_OPT_SET(options, HAS_CHANGES);
4684         else
4685                 DIFF_OPT_CLR(options, HAS_CHANGES);
4686
4687         options->found_follow = 0;
4688 }
4689
4690 int diff_result_code(struct diff_options *opt, int status)
4691 {
4692         int result = 0;
4693
4694         diff_warn_rename_limit("diff.renamelimit",
4695                                opt->needed_rename_limit,
4696                                opt->degraded_cc_to_c);
4697         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4698             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4699                 return status;
4700         if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4701             DIFF_OPT_TST(opt, HAS_CHANGES))
4702                 result |= 01;
4703         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4704             DIFF_OPT_TST(opt, CHECK_FAILED))
4705                 result |= 02;
4706         return result;
4707 }
4708
4709 int diff_can_quit_early(struct diff_options *opt)
4710 {
4711         return (DIFF_OPT_TST(opt, QUICK) &&
4712                 !opt->filter &&
4713                 DIFF_OPT_TST(opt, HAS_CHANGES));
4714 }
4715
4716 /*
4717  * Shall changes to this submodule be ignored?
4718  *
4719  * Submodule changes can be configured to be ignored separately for each path,
4720  * but that configuration can be overridden from the command line.
4721  */
4722 static int is_submodule_ignored(const char *path, struct diff_options *options)
4723 {
4724         int ignored = 0;
4725         unsigned orig_flags = options->flags;
4726         if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4727                 set_diffopt_flags_from_submodule_config(options, path);
4728         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4729                 ignored = 1;
4730         options->flags = orig_flags;
4731         return ignored;
4732 }
4733
4734 void diff_addremove(struct diff_options *options,
4735                     int addremove, unsigned mode,
4736                     const unsigned char *sha1,
4737                     int sha1_valid,
4738                     const char *concatpath, unsigned dirty_submodule)
4739 {
4740         struct diff_filespec *one, *two;
4741
4742         if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4743                 return;
4744
4745         /* This may look odd, but it is a preparation for
4746          * feeding "there are unchanged files which should
4747          * not produce diffs, but when you are doing copy
4748          * detection you would need them, so here they are"
4749          * entries to the diff-core.  They will be prefixed
4750          * with something like '=' or '*' (I haven't decided
4751          * which but should not make any difference).
4752          * Feeding the same new and old to diff_change()
4753          * also has the same effect.
4754          * Before the final output happens, they are pruned after
4755          * merged into rename/copy pairs as appropriate.
4756          */
4757         if (DIFF_OPT_TST(options, REVERSE_DIFF))
4758                 addremove = (addremove == '+' ? '-' :
4759                              addremove == '-' ? '+' : addremove);
4760
4761         if (options->prefix &&
4762             strncmp(concatpath, options->prefix, options->prefix_length))
4763                 return;
4764
4765         one = alloc_filespec(concatpath);
4766         two = alloc_filespec(concatpath);
4767
4768         if (addremove != '+')
4769                 fill_filespec(one, sha1, sha1_valid, mode);
4770         if (addremove != '-') {
4771                 fill_filespec(two, sha1, sha1_valid, mode);
4772                 two->dirty_submodule = dirty_submodule;
4773         }
4774
4775         diff_queue(&diff_queued_diff, one, two);
4776         if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4777                 DIFF_OPT_SET(options, HAS_CHANGES);
4778 }
4779
4780 void diff_change(struct diff_options *options,
4781                  unsigned old_mode, unsigned new_mode,
4782                  const unsigned char *old_sha1,
4783                  const unsigned char *new_sha1,
4784                  int old_sha1_valid, int new_sha1_valid,
4785                  const char *concatpath,
4786                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4787 {
4788         struct diff_filespec *one, *two;
4789
4790         if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4791             is_submodule_ignored(concatpath, options))
4792                 return;
4793
4794         if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
4795                 unsigned tmp;
4796                 const unsigned char *tmp_c;
4797                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
4798                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
4799                 tmp = old_sha1_valid; old_sha1_valid = new_sha1_valid;
4800                         new_sha1_valid = tmp;
4801                 tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
4802                         new_dirty_submodule = tmp;
4803         }
4804
4805         if (options->prefix &&
4806             strncmp(concatpath, options->prefix, options->prefix_length))
4807                 return;
4808
4809         one = alloc_filespec(concatpath);
4810         two = alloc_filespec(concatpath);
4811         fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
4812         fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
4813         one->dirty_submodule = old_dirty_submodule;
4814         two->dirty_submodule = new_dirty_submodule;
4815
4816         diff_queue(&diff_queued_diff, one, two);
4817         if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4818                 DIFF_OPT_SET(options, HAS_CHANGES);
4819 }
4820
4821 struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
4822 {
4823         struct diff_filepair *pair;
4824         struct diff_filespec *one, *two;
4825
4826         if (options->prefix &&
4827             strncmp(path, options->prefix, options->prefix_length))
4828                 return NULL;
4829
4830         one = alloc_filespec(path);
4831         two = alloc_filespec(path);
4832         pair = diff_queue(&diff_queued_diff, one, two);
4833         pair->is_unmerged = 1;
4834         return pair;
4835 }
4836
4837 static char *run_textconv(const char *pgm, struct diff_filespec *spec,
4838                 size_t *outsize)
4839 {
4840         struct diff_tempfile *temp;
4841         const char *argv[3];
4842         const char **arg = argv;
4843         struct child_process child;
4844         struct strbuf buf = STRBUF_INIT;
4845         int err = 0;
4846
4847         temp = prepare_temp_file(spec->path, spec);
4848         *arg++ = pgm;
4849         *arg++ = temp->name;
4850         *arg = NULL;
4851
4852         memset(&child, 0, sizeof(child));
4853         child.use_shell = 1;
4854         child.argv = argv;
4855         child.out = -1;
4856         if (start_command(&child)) {
4857                 remove_tempfile();
4858                 return NULL;
4859         }
4860
4861         if (strbuf_read(&buf, child.out, 0) < 0)
4862                 err = error("error reading from textconv command '%s'", pgm);
4863         close(child.out);
4864
4865         if (finish_command(&child) || err) {
4866                 strbuf_release(&buf);
4867                 remove_tempfile();
4868                 return NULL;
4869         }
4870         remove_tempfile();
4871
4872         return strbuf_detach(&buf, outsize);
4873 }
4874
4875 size_t fill_textconv(struct userdiff_driver *driver,
4876                      struct diff_filespec *df,
4877                      char **outbuf)
4878 {
4879         size_t size;
4880
4881         if (!driver || !driver->textconv) {
4882                 if (!DIFF_FILE_VALID(df)) {
4883                         *outbuf = "";
4884                         return 0;
4885                 }
4886                 if (diff_populate_filespec(df, 0))
4887                         die("unable to read files to diff");
4888                 *outbuf = df->data;
4889                 return df->size;
4890         }
4891
4892         if (driver->textconv_cache && df->sha1_valid) {
4893                 *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
4894                                           &size);
4895                 if (*outbuf)
4896                         return size;
4897         }
4898
4899         *outbuf = run_textconv(driver->textconv, df, &size);
4900         if (!*outbuf)
4901                 die("unable to read files to diff");
4902
4903         if (driver->textconv_cache && df->sha1_valid) {
4904                 /* ignore errors, as we might be in a readonly repository */
4905                 notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
4906                                 size);
4907                 /*
4908                  * we could save up changes and flush them all at the end,
4909                  * but we would need an extra call after all diffing is done.
4910                  * Since generating a cache entry is the slow path anyway,
4911                  * this extra overhead probably isn't a big deal.
4912                  */
4913                 notes_cache_write(driver->textconv_cache);
4914         }
4915
4916         return size;
4917 }
4918
4919 void setup_diff_pager(struct diff_options *opt)
4920 {
4921         /*
4922          * If the user asked for our exit code, then either they want --quiet
4923          * or --exit-code. We should definitely not bother with a pager in the
4924          * former case, as we will generate no output. Since we still properly
4925          * report our exit code even when a pager is run, we _could_ run a
4926          * pager with --exit-code. But since we have not done so historically,
4927          * and because it is easy to find people oneline advising "git diff
4928          * --exit-code" in hooks and other scripts, we do not do so.
4929          */
4930         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4931             check_pager_config("diff") != 0)
4932                 setup_pager();
4933 }