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