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