git.oblomov.eu Git - git/blob - 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
  15 #ifdef NO_FAST_WORKING_DIRECTORY
  16 #define FAST_WORKING_DIRECTORY 0
  17 #else
  18 #define FAST_WORKING_DIRECTORY 1
  19 #endif
  20
  21 static int diff_detect_rename_default;
  22 static int diff_rename_limit_default = 200;
  23 static int diff_suppress_blank_empty;
  24 int diff_use_color_default = -1;
  25 static const char *external_diff_cmd_cfg;
  26 int diff_auto_refresh_index = 1;
  27
  28 static char diff_colors[][COLOR_MAXLEN] = {
  29         "\033[m",       /* reset */
  30         "",             /* PLAIN (normal) */
  31         "\033[1m",      /* METAINFO (bold) */
  32         "\033[36m",     /* FRAGINFO (cyan) */
  33         "\033[31m",     /* OLD (red) */
  34         "\033[32m",     /* NEW (green) */
  35         "\033[33m",     /* COMMIT (yellow) */
  36         "\033[41m",     /* WHITESPACE (red background) */
  37 };
  38
  39 static int parse_diff_color_slot(const char *var, int ofs)
  40 {
  41         if (!strcasecmp(var+ofs, "plain"))
  42                 return DIFF_PLAIN;
  43         if (!strcasecmp(var+ofs, "meta"))
  44                 return DIFF_METAINFO;
  45         if (!strcasecmp(var+ofs, "frag"))
  46                 return DIFF_FRAGINFO;
  47         if (!strcasecmp(var+ofs, "old"))
  48                 return DIFF_FILE_OLD;
  49         if (!strcasecmp(var+ofs, "new"))
  50                 return DIFF_FILE_NEW;
  51         if (!strcasecmp(var+ofs, "commit"))
  52                 return DIFF_COMMIT;
  53         if (!strcasecmp(var+ofs, "whitespace"))
  54                 return DIFF_WHITESPACE;
  55         die("bad config variable '%s'", var);
  56 }
  57
  58 static struct ll_diff_driver {
  59         const char *name;
  60         struct ll_diff_driver *next;
  61         const char *cmd;
  62 } *user_diff, **user_diff_tail;
  63
  64 /*
  65  * Currently there is only "diff.<drivername>.command" variable;
  66  * because there are "diff.color.<slot>" variables, we are parsing
  67  * this in a bit convoluted way to allow low level diff driver
  68  * called "color".
  69  */
  70 static int parse_lldiff_command(const char *var, const char *ep, const char *value)
  71 {
  72         const char *name;
  73         int namelen;
  74         struct ll_diff_driver *drv;
  75
  76         name = var + 5;
  77         namelen = ep - name;
  78         for (drv = user_diff; drv; drv = drv->next)
  79                 if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
  80                         break;
  81         if (!drv) {
  82                 drv = xcalloc(1, sizeof(struct ll_diff_driver));
  83                 drv->name = xmemdupz(name, namelen);
  84                 if (!user_diff_tail)
  85                         user_diff_tail = &user_diff;
  86                 *user_diff_tail = drv;
  87                 user_diff_tail = &(drv->next);
  88         }
  89
  90         return git_config_string(&(drv->cmd), var, value);
  91 }
  92
  93 /*
  94  * 'diff.<what>.funcname' attribute can be specified in the configuration
  95  * to define a customized regexp to find the beginning of a function to
  96  * be used for hunk header lines of "diff -p" style output.
  97  */
  98 static struct funcname_pattern {
  99         char *name;
 100         char *pattern;
 101         struct funcname_pattern *next;
 102 } *funcname_pattern_list;
 103
 104 static int parse_funcname_pattern(const char *var, const char *ep, const char *value)
 105 {
 106         const char *name;
 107         int namelen;
 108         struct funcname_pattern *pp;
 109
 110         name = var + 5; /* "diff." */
 111         namelen = ep - name;
 112
 113         for (pp = funcname_pattern_list; pp; pp = pp->next)
 114                 if (!strncmp(pp->name, name, namelen) && !pp->name[namelen])
 115                         break;
 116         if (!pp) {
 117                 pp = xcalloc(1, sizeof(*pp));
 118                 pp->name = xmemdupz(name, namelen);
 119                 pp->next = funcname_pattern_list;
 120                 funcname_pattern_list = pp;
 121         }
 122         free(pp->pattern);
 123         pp->pattern = xstrdup(value);
 124         return 0;
 125 }
 126
 127 /*
 128  * These are to give UI layer defaults.
 129  * The core-level commands such as git-diff-files should
 130  * never be affected by the setting of diff.renames
 131  * the user happens to have in the configuration file.
 132  */
 133 int git_diff_ui_config(const char *var, const char *value, void *cb)
 134 {
 135         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 136                 diff_use_color_default = git_config_colorbool(var, value, -1);
 137                 return 0;
 138         }
 139         if (!strcmp(var, "diff.renames")) {
 140                 if (!value)
 141                         diff_detect_rename_default = DIFF_DETECT_RENAME;
 142                 else if (!strcasecmp(value, "copies") ||
 143                          !strcasecmp(value, "copy"))
 144                         diff_detect_rename_default = DIFF_DETECT_COPY;
 145                 else if (git_config_bool(var,value))
 146                         diff_detect_rename_default = DIFF_DETECT_RENAME;
 147                 return 0;
 148         }
 149         if (!strcmp(var, "diff.autorefreshindex")) {
 150                 diff_auto_refresh_index = git_config_bool(var, value);
 151                 return 0;
 152         }
 153         if (!strcmp(var, "diff.external"))
 154                 return git_config_string(&external_diff_cmd_cfg, var, value);
 155         if (!prefixcmp(var, "diff.")) {
 156                 const char *ep = strrchr(var, '.');
 157
 158                 if (ep != var + 4 && !strcmp(ep, ".command"))
 159                         return parse_lldiff_command(var, ep, value);
 160         }
 161
 162         return git_diff_basic_config(var, value, cb);
 163 }
 164
 165 int git_diff_basic_config(const char *var, const char *value, void *cb)
 166 {
 167         if (!strcmp(var, "diff.renamelimit")) {
 168                 diff_rename_limit_default = git_config_int(var, value);
 169                 return 0;
 170         }
 171
 172         if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
 173                 int slot = parse_diff_color_slot(var, 11);
 174                 if (!value)
 175                         return config_error_nonbool(var);
 176                 color_parse(value, var, diff_colors[slot]);
 177                 return 0;
 178         }
 179
 180         /* like GNU diff's --suppress-blank-empty option  */
 181         if (!strcmp(var, "diff.suppress-blank-empty")) {
 182                 diff_suppress_blank_empty = git_config_bool(var, value);
 183                 return 0;
 184         }
 185
 186         if (!prefixcmp(var, "diff.")) {
 187                 const char *ep = strrchr(var, '.');
 188                 if (ep != var + 4) {
 189                         if (!strcmp(ep, ".funcname")) {
 190                                 if (!value)
 191                                         return config_error_nonbool(var);
 192                                 return parse_funcname_pattern(var, ep, value);
 193                         }
 194                 }
 195         }
 196
 197         return git_color_default_config(var, value, cb);
 198 }
 199
 200 static char *quote_two(const char *one, const char *two)
 201 {
 202         int need_one = quote_c_style(one, NULL, NULL, 1);
 203         int need_two = quote_c_style(two, NULL, NULL, 1);
 204         struct strbuf res;
 205
 206         strbuf_init(&res, 0);
 207         if (need_one + need_two) {
 208                 strbuf_addch(&res, '"');
 209                 quote_c_style(one, &res, NULL, 1);
 210                 quote_c_style(two, &res, NULL, 1);
 211                 strbuf_addch(&res, '"');
 212         } else {
 213                 strbuf_addstr(&res, one);
 214                 strbuf_addstr(&res, two);
 215         }
 216         return strbuf_detach(&res, NULL);
 217 }
 218
 219 static const char *external_diff(void)
 220 {
 221         static const char *external_diff_cmd = NULL;
 222         static int done_preparing = 0;
 223
 224         if (done_preparing)
 225                 return external_diff_cmd;
 226         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 227         if (!external_diff_cmd)
 228                 external_diff_cmd = external_diff_cmd_cfg;
 229         done_preparing = 1;
 230         return external_diff_cmd;
 231 }
 232
 233 static struct diff_tempfile {
 234         const char *name; /* filename external diff should read from */
 235         char hex[41];
 236         char mode[10];
 237         char tmp_path[PATH_MAX];
 238 } diff_temp[2];
 239
 240 static int count_lines(const char *data, int size)
 241 {
 242         int count, ch, completely_empty = 1, nl_just_seen = 0;
 243         count = 0;
 244         while (0 < size--) {
 245                 ch = *data++;
 246                 if (ch == '\n') {
 247                         count++;
 248                         nl_just_seen = 1;
 249                         completely_empty = 0;
 250                 }
 251                 else {
 252                         nl_just_seen = 0;
 253                         completely_empty = 0;
 254                 }
 255         }
 256         if (completely_empty)
 257                 return 0;
 258         if (!nl_just_seen)
 259                 count++; /* no trailing newline */
 260         return count;
 261 }
 262
 263 static void print_line_count(FILE *file, int count)
 264 {
 265         switch (count) {
 266         case 0:
 267                 fprintf(file, "0,0");
 268                 break;
 269         case 1:
 270                 fprintf(file, "1");
 271                 break;
 272         default:
 273                 fprintf(file, "1,%d", count);
 274                 break;
 275         }
 276 }
 277
 278 static void copy_file_with_prefix(FILE *file,
 279                                   int prefix, const char *data, int size,
 280                                   const char *set, const char *reset)
 281 {
 282         int ch, nl_just_seen = 1;
 283         while (0 < size--) {
 284                 ch = *data++;
 285                 if (nl_just_seen) {
 286                         fputs(set, file);
 287                         putc(prefix, file);
 288                 }
 289                 if (ch == '\n') {
 290                         nl_just_seen = 1;
 291                         fputs(reset, file);
 292                 } else
 293                         nl_just_seen = 0;
 294                 putc(ch, file);
 295         }
 296         if (!nl_just_seen)
 297                 fprintf(file, "%s\n\\ No newline at end of file\n", reset);
 298 }
 299
 300 static void emit_rewrite_diff(const char *name_a,
 301                               const char *name_b,
 302                               struct diff_filespec *one,
 303                               struct diff_filespec *two,
 304                               struct diff_options *o)
 305 {
 306         int lc_a, lc_b;
 307         int color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
 308         const char *name_a_tab, *name_b_tab;
 309         const char *metainfo = diff_get_color(color_diff, DIFF_METAINFO);
 310         const char *fraginfo = diff_get_color(color_diff, DIFF_FRAGINFO);
 311         const char *old = diff_get_color(color_diff, DIFF_FILE_OLD);
 312         const char *new = diff_get_color(color_diff, DIFF_FILE_NEW);
 313         const char *reset = diff_get_color(color_diff, DIFF_RESET);
 314         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 315
 316         name_a += (*name_a == '/');
 317         name_b += (*name_b == '/');
 318         name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 319         name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 320
 321         strbuf_reset(&a_name);
 322         strbuf_reset(&b_name);
 323         quote_two_c_style(&a_name, o->a_prefix, name_a, 0);
 324         quote_two_c_style(&b_name, o->b_prefix, name_b, 0);
 325
 326         diff_populate_filespec(one, 0);
 327         diff_populate_filespec(two, 0);
 328         lc_a = count_lines(one->data, one->size);
 329         lc_b = count_lines(two->data, two->size);
 330         fprintf(o->file,
 331                 "%s--- %s%s%s\n%s+++ %s%s%s\n%s@@ -",
 332                 metainfo, a_name.buf, name_a_tab, reset,
 333                 metainfo, b_name.buf, name_b_tab, reset, fraginfo);
 334         print_line_count(o->file, lc_a);
 335         fprintf(o->file, " +");
 336         print_line_count(o->file, lc_b);
 337         fprintf(o->file, " @@%s\n", reset);
 338         if (lc_a)
 339                 copy_file_with_prefix(o->file, '-', one->data, one->size, old, reset);
 340         if (lc_b)
 341                 copy_file_with_prefix(o->file, '+', two->data, two->size, new, reset);
 342 }
 343
 344 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 345 {
 346         if (!DIFF_FILE_VALID(one)) {
 347                 mf->ptr = (char *)""; /* does not matter */
 348                 mf->size = 0;
 349                 return 0;
 350         }
 351         else if (diff_populate_filespec(one, 0))
 352                 return -1;
 353         mf->ptr = one->data;
 354         mf->size = one->size;
 355         return 0;
 356 }
 357
 358 struct diff_words_buffer {
 359         mmfile_t text;
 360         long alloc;
 361         long current; /* output pointer */
 362         int suppressed_newline;
 363 };
 364
 365 static void diff_words_append(char *line, unsigned long len,
 366                 struct diff_words_buffer *buffer)
 367 {
 368         if (buffer->text.size + len > buffer->alloc) {
 369                 buffer->alloc = (buffer->text.size + len) * 3 / 2;
 370                 buffer->text.ptr = xrealloc(buffer->text.ptr, buffer->alloc);
 371         }
 372         line++;
 373         len--;
 374         memcpy(buffer->text.ptr + buffer->text.size, line, len);
 375         buffer->text.size += len;
 376 }
 377
 378 struct diff_words_data {
 379         struct diff_words_buffer minus, plus;
 380         FILE *file;
 381 };
 382
 383 static void print_word(FILE *file, struct diff_words_buffer *buffer, int len, int color,
 384                 int suppress_newline)
 385 {
 386         const char *ptr;
 387         int eol = 0;
 388
 389         if (len == 0)
 390                 return;
 391
 392         ptr  = buffer->text.ptr + buffer->current;
 393         buffer->current += len;
 394
 395         if (ptr[len - 1] == '\n') {
 396                 eol = 1;
 397                 len--;
 398         }
 399
 400         fputs(diff_get_color(1, color), file);
 401         fwrite(ptr, len, 1, file);
 402         fputs(diff_get_color(1, DIFF_RESET), file);
 403
 404         if (eol) {
 405                 if (suppress_newline)
 406                         buffer->suppressed_newline = 1;
 407                 else
 408                         putc('\n', file);
 409         }
 410 }
 411
 412 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 413 {
 414         struct diff_words_data *diff_words = priv;
 415
 416         if (diff_words->minus.suppressed_newline) {
 417                 if (line[0] != '+')
 418                         putc('\n', diff_words->file);
 419                 diff_words->minus.suppressed_newline = 0;
 420         }
 421
 422         len--;
 423         switch (line[0]) {
 424                 case '-':
 425                         print_word(diff_words->file,
 426                                    &diff_words->minus, len, DIFF_FILE_OLD, 1);
 427                         break;
 428                 case '+':
 429                         print_word(diff_words->file,
 430                                    &diff_words->plus, len, DIFF_FILE_NEW, 0);
 431                         break;
 432                 case ' ':
 433                         print_word(diff_words->file,
 434                                    &diff_words->plus, len, DIFF_PLAIN, 0);
 435                         diff_words->minus.current += len;
 436                         break;
 437         }
 438 }
 439
 440 /* this executes the word diff on the accumulated buffers */
 441 static void diff_words_show(struct diff_words_data *diff_words)
 442 {
 443         xpparam_t xpp;
 444         xdemitconf_t xecfg;
 445         xdemitcb_t ecb;
 446         mmfile_t minus, plus;
 447         int i;
 448
 449         memset(&xecfg, 0, sizeof(xecfg));
 450         minus.size = diff_words->minus.text.size;
 451         minus.ptr = xmalloc(minus.size);
 452         memcpy(minus.ptr, diff_words->minus.text.ptr, minus.size);
 453         for (i = 0; i < minus.size; i++)
 454                 if (isspace(minus.ptr[i]))
 455                         minus.ptr[i] = '\n';
 456         diff_words->minus.current = 0;
 457
 458         plus.size = diff_words->plus.text.size;
 459         plus.ptr = xmalloc(plus.size);
 460         memcpy(plus.ptr, diff_words->plus.text.ptr, plus.size);
 461         for (i = 0; i < plus.size; i++)
 462                 if (isspace(plus.ptr[i]))
 463                         plus.ptr[i] = '\n';
 464         diff_words->plus.current = 0;
 465
 466         xpp.flags = XDF_NEED_MINIMAL;
 467         xecfg.ctxlen = diff_words->minus.alloc + diff_words->plus.alloc;
 468         xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
 469                       &xpp, &xecfg, &ecb);
 470         free(minus.ptr);
 471         free(plus.ptr);
 472         diff_words->minus.text.size = diff_words->plus.text.size = 0;
 473
 474         if (diff_words->minus.suppressed_newline) {
 475                 putc('\n', diff_words->file);
 476                 diff_words->minus.suppressed_newline = 0;
 477         }
 478 }
 479
 480 typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 481
 482 struct emit_callback {
 483         int nparents, color_diff;
 484         unsigned ws_rule;
 485         sane_truncate_fn truncate;
 486         const char **label_path;
 487         struct diff_words_data *diff_words;
 488         int *found_changesp;
 489         FILE *file;
 490 };
 491
 492 static void free_diff_words_data(struct emit_callback *ecbdata)
 493 {
 494         if (ecbdata->diff_words) {
 495                 /* flush buffers */
 496                 if (ecbdata->diff_words->minus.text.size ||
 497                                 ecbdata->diff_words->plus.text.size)
 498                         diff_words_show(ecbdata->diff_words);
 499
 500                 free (ecbdata->diff_words->minus.text.ptr);
 501                 free (ecbdata->diff_words->plus.text.ptr);
 502                 free(ecbdata->diff_words);
 503                 ecbdata->diff_words = NULL;
 504         }
 505 }
 506
 507 const char *diff_get_color(int diff_use_color, enum color_diff ix)
 508 {
 509         if (diff_use_color)
 510                 return diff_colors[ix];
 511         return "";
 512 }
 513
 514 static void emit_line(FILE *file, const char *set, const char *reset, const char *line, int len)
 515 {
 516         int has_trailing_newline = (len > 0 && line[len-1] == '\n');
 517         if (has_trailing_newline)
 518                 len--;
 519
 520         fputs(set, file);
 521         fwrite(line, len, 1, file);
 522         fputs(reset, file);
 523         if (has_trailing_newline)
 524                 fputc('\n', file);
 525 }
 526
 527 static void emit_add_line(const char *reset, struct emit_callback *ecbdata, const char *line, int len)
 528 {
 529         const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 530         const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
 531
 532         if (!*ws)
 533                 emit_line(ecbdata->file, set, reset, line, len);
 534         else {
 535                 /* Emit just the prefix, then the rest. */
 536                 emit_line(ecbdata->file, set, reset, line, ecbdata->nparents);
 537                 ws_check_emit(line + ecbdata->nparents,
 538                               len - ecbdata->nparents, ecbdata->ws_rule,
 539                               ecbdata->file, set, reset, ws);
 540         }
 541 }
 542
 543 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
 544 {
 545         const char *cp;
 546         unsigned long allot;
 547         size_t l = len;
 548
 549         if (ecb->truncate)
 550                 return ecb->truncate(line, len);
 551         cp = line;
 552         allot = l;
 553         while (0 < l) {
 554                 (void) utf8_width(&cp, &l);
 555                 if (!cp)
 556                         break; /* truncated in the middle? */
 557         }
 558         return allot - l;
 559 }
 560
 561 static void fn_out_consume(void *priv, char *line, unsigned long len)
 562 {
 563         int i;
 564         int color;
 565         struct emit_callback *ecbdata = priv;
 566         const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
 567         const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
 568         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 569
 570         *(ecbdata->found_changesp) = 1;
 571
 572         if (ecbdata->label_path[0]) {
 573                 const char *name_a_tab, *name_b_tab;
 574
 575                 name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
 576                 name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
 577
 578                 fprintf(ecbdata->file, "%s--- %s%s%s\n",
 579                         meta, ecbdata->label_path[0], reset, name_a_tab);
 580                 fprintf(ecbdata->file, "%s+++ %s%s%s\n",
 581                         meta, ecbdata->label_path[1], reset, name_b_tab);
 582                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
 583         }
 584
 585         if (diff_suppress_blank_empty
 586             && len == 2 && line[0] == ' ' && line[1] == '\n') {
 587                 line[0] = '\n';
 588                 len = 1;
 589         }
 590
 591         /* This is not really necessary for now because
 592          * this codepath only deals with two-way diffs.
 593          */
 594         for (i = 0; i < len && line[i] == '@'; i++)
 595                 ;
 596         if (2 <= i && i < len && line[i] == ' ') {
 597                 ecbdata->nparents = i - 1;
 598                 len = sane_truncate_line(ecbdata, line, len);
 599                 emit_line(ecbdata->file,
 600                           diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO),
 601                           reset, line, len);
 602                 if (line[len-1] != '\n')
 603                         putc('\n', ecbdata->file);
 604                 return;
 605         }
 606
 607         if (len < ecbdata->nparents) {
 608                 emit_line(ecbdata->file, reset, reset, line, len);
 609                 return;
 610         }
 611
 612         color = DIFF_PLAIN;
 613         if (ecbdata->diff_words && ecbdata->nparents != 1)
 614                 /* fall back to normal diff */
 615                 free_diff_words_data(ecbdata);
 616         if (ecbdata->diff_words) {
 617                 if (line[0] == '-') {
 618                         diff_words_append(line, len,
 619                                           &ecbdata->diff_words->minus);
 620                         return;
 621                 } else if (line[0] == '+') {
 622                         diff_words_append(line, len,
 623                                           &ecbdata->diff_words->plus);
 624                         return;
 625                 }
 626                 if (ecbdata->diff_words->minus.text.size ||
 627                     ecbdata->diff_words->plus.text.size)
 628                         diff_words_show(ecbdata->diff_words);
 629                 line++;
 630                 len--;
 631                 emit_line(ecbdata->file, plain, reset, line, len);
 632                 return;
 633         }
 634         for (i = 0; i < ecbdata->nparents && len; i++) {
 635                 if (line[i] == '-')
 636                         color = DIFF_FILE_OLD;
 637                 else if (line[i] == '+')
 638                         color = DIFF_FILE_NEW;
 639         }
 640
 641         if (color != DIFF_FILE_NEW) {
 642                 emit_line(ecbdata->file,
 643                           diff_get_color(ecbdata->color_diff, color),
 644                           reset, line, len);
 645                 return;
 646         }
 647         emit_add_line(reset, ecbdata, line, len);
 648 }
 649
 650 static char *pprint_rename(const char *a, const char *b)
 651 {
 652         const char *old = a;
 653         const char *new = b;
 654         struct strbuf name;
 655         int pfx_length, sfx_length;
 656         int len_a = strlen(a);
 657         int len_b = strlen(b);
 658         int a_midlen, b_midlen;
 659         int qlen_a = quote_c_style(a, NULL, NULL, 0);
 660         int qlen_b = quote_c_style(b, NULL, NULL, 0);
 661
 662         strbuf_init(&name, 0);
 663         if (qlen_a || qlen_b) {
 664                 quote_c_style(a, &name, NULL, 0);
 665                 strbuf_addstr(&name, " => ");
 666                 quote_c_style(b, &name, NULL, 0);
 667                 return strbuf_detach(&name, NULL);
 668         }
 669
 670         /* Find common prefix */
 671         pfx_length = 0;
 672         while (*old && *new && *old == *new) {
 673                 if (*old == '/')
 674                         pfx_length = old - a + 1;
 675                 old++;
 676                 new++;
 677         }
 678
 679         /* Find common suffix */
 680         old = a + len_a;
 681         new = b + len_b;
 682         sfx_length = 0;
 683         while (a <= old && b <= new && *old == *new) {
 684                 if (*old == '/')
 685                         sfx_length = len_a - (old - a);
 686                 old--;
 687                 new--;
 688         }
 689
 690         /*
 691          * pfx{mid-a => mid-b}sfx
 692          * {pfx-a => pfx-b}sfx
 693          * pfx{sfx-a => sfx-b}
 694          * name-a => name-b
 695          */
 696         a_midlen = len_a - pfx_length - sfx_length;
 697         b_midlen = len_b - pfx_length - sfx_length;
 698         if (a_midlen < 0)
 699                 a_midlen = 0;
 700         if (b_midlen < 0)
 701                 b_midlen = 0;
 702
 703         strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
 704         if (pfx_length + sfx_length) {
 705                 strbuf_add(&name, a, pfx_length);
 706                 strbuf_addch(&name, '{');
 707         }
 708         strbuf_add(&name, a + pfx_length, a_midlen);
 709         strbuf_addstr(&name, " => ");
 710         strbuf_add(&name, b + pfx_length, b_midlen);
 711         if (pfx_length + sfx_length) {
 712                 strbuf_addch(&name, '}');
 713                 strbuf_add(&name, a + len_a - sfx_length, sfx_length);
 714         }
 715         return strbuf_detach(&name, NULL);
 716 }
 717
 718 struct diffstat_t {
 719         int nr;
 720         int alloc;
 721         struct diffstat_file {
 722                 char *from_name;
 723                 char *name;
 724                 char *print_name;
 725                 unsigned is_unmerged:1;
 726                 unsigned is_binary:1;
 727                 unsigned is_renamed:1;
 728                 unsigned int added, deleted;
 729         } **files;
 730 };
 731
 732 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
 733                                           const char *name_a,
 734                                           const char *name_b)
 735 {
 736         struct diffstat_file *x;
 737         x = xcalloc(sizeof (*x), 1);
 738         if (diffstat->nr == diffstat->alloc) {
 739                 diffstat->alloc = alloc_nr(diffstat->alloc);
 740                 diffstat->files = xrealloc(diffstat->files,
 741                                 diffstat->alloc * sizeof(x));
 742         }
 743         diffstat->files[diffstat->nr++] = x;
 744         if (name_b) {
 745                 x->from_name = xstrdup(name_a);
 746                 x->name = xstrdup(name_b);
 747                 x->is_renamed = 1;
 748         }
 749         else {
 750                 x->from_name = NULL;
 751                 x->name = xstrdup(name_a);
 752         }
 753         return x;
 754 }
 755
 756 static void diffstat_consume(void *priv, char *line, unsigned long len)
 757 {
 758         struct diffstat_t *diffstat = priv;
 759         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
 760
 761         if (line[0] == '+')
 762                 x->added++;
 763         else if (line[0] == '-')
 764                 x->deleted++;
 765 }
 766
 767 const char mime_boundary_leader[] = "------------";
 768
 769 static int scale_linear(int it, int width, int max_change)
 770 {
 771         /*
 772          * make sure that at least one '-' is printed if there were deletions,
 773          * and likewise for '+'.
 774          */
 775         if (max_change < 2)
 776                 return it;
 777         return ((it - 1) * (width - 1) + max_change - 1) / (max_change - 1);
 778 }
 779
 780 static void show_name(FILE *file,
 781                       const char *prefix, const char *name, int len,
 782                       const char *reset, const char *set)
 783 {
 784         fprintf(file, " %s%s%-*s%s |", set, prefix, len, name, reset);
 785 }
 786
 787 static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
 788 {
 789         if (cnt <= 0)
 790                 return;
 791         fprintf(file, "%s", set);
 792         while (cnt--)
 793                 putc(ch, file);
 794         fprintf(file, "%s", reset);
 795 }
 796
 797 static void fill_print_name(struct diffstat_file *file)
 798 {
 799         char *pname;
 800
 801         if (file->print_name)
 802                 return;
 803
 804         if (!file->is_renamed) {
 805                 struct strbuf buf;
 806                 strbuf_init(&buf, 0);
 807                 if (quote_c_style(file->name, &buf, NULL, 0)) {
 808                         pname = strbuf_detach(&buf, NULL);
 809                 } else {
 810                         pname = file->name;
 811                         strbuf_release(&buf);
 812                 }
 813         } else {
 814                 pname = pprint_rename(file->from_name, file->name);
 815         }
 816         file->print_name = pname;
 817 }
 818
 819 static void show_stats(struct diffstat_t* data, struct diff_options *options)
 820 {
 821         int i, len, add, del, total, adds = 0, dels = 0;
 822         int max_change = 0, max_len = 0;
 823         int total_files = data->nr;
 824         int width, name_width;
 825         const char *reset, *set, *add_c, *del_c;
 826
 827         if (data->nr == 0)
 828                 return;
 829
 830         width = options->stat_width ? options->stat_width : 80;
 831         name_width = options->stat_name_width ? options->stat_name_width : 50;
 832
 833         /* Sanity: give at least 5 columns to the graph,
 834          * but leave at least 10 columns for the name.
 835          */
 836         if (width < 25)
 837                 width = 25;
 838         if (name_width < 10)
 839                 name_width = 10;
 840         else if (width < name_width + 15)
 841                 name_width = width - 15;
 842
 843         /* Find the longest filename and max number of changes */
 844         reset = diff_get_color_opt(options, DIFF_RESET);
 845         set   = diff_get_color_opt(options, DIFF_PLAIN);
 846         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
 847         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
 848
 849         for (i = 0; i < data->nr; i++) {
 850                 struct diffstat_file *file = data->files[i];
 851                 int change = file->added + file->deleted;
 852                 fill_print_name(file);
 853                 len = strlen(file->print_name);
 854                 if (max_len < len)
 855                         max_len = len;
 856
 857                 if (file->is_binary || file->is_unmerged)
 858                         continue;
 859                 if (max_change < change)
 860                         max_change = change;
 861         }
 862
 863         /* Compute the width of the graph part;
 864          * 10 is for one blank at the beginning of the line plus
 865          * " | count " between the name and the graph.
 866          *
 867          * From here on, name_width is the width of the name area,
 868          * and width is the width of the graph area.
 869          */
 870         name_width = (name_width < max_len) ? name_width : max_len;
 871         if (width < (name_width + 10) + max_change)
 872                 width = width - (name_width + 10);
 873         else
 874                 width = max_change;
 875
 876         for (i = 0; i < data->nr; i++) {
 877                 const char *prefix = "";
 878                 char *name = data->files[i]->print_name;
 879                 int added = data->files[i]->added;
 880                 int deleted = data->files[i]->deleted;
 881                 int name_len;
 882
 883                 /*
 884                  * "scale" the filename
 885                  */
 886                 len = name_width;
 887                 name_len = strlen(name);
 888                 if (name_width < name_len) {
 889                         char *slash;
 890                         prefix = "...";
 891                         len -= 3;
 892                         name += name_len - len;
 893                         slash = strchr(name, '/');
 894                         if (slash)
 895                                 name = slash;
 896                 }
 897
 898                 if (data->files[i]->is_binary) {
 899                         show_name(options->file, prefix, name, len, reset, set);
 900                         fprintf(options->file, "  Bin ");
 901                         fprintf(options->file, "%s%d%s", del_c, deleted, reset);
 902                         fprintf(options->file, " -> ");
 903                         fprintf(options->file, "%s%d%s", add_c, added, reset);
 904                         fprintf(options->file, " bytes");
 905                         fprintf(options->file, "\n");
 906                         continue;
 907                 }
 908                 else if (data->files[i]->is_unmerged) {
 909                         show_name(options->file, prefix, name, len, reset, set);
 910                         fprintf(options->file, "  Unmerged\n");
 911                         continue;
 912                 }
 913                 else if (!data->files[i]->is_renamed &&
 914                          (added + deleted == 0)) {
 915                         total_files--;
 916                         continue;
 917                 }
 918
 919                 /*
 920                  * scale the add/delete
 921                  */
 922                 add = added;
 923                 del = deleted;
 924                 total = add + del;
 925                 adds += add;
 926                 dels += del;
 927
 928                 if (width <= max_change) {
 929                         add = scale_linear(add, width, max_change);
 930                         del = scale_linear(del, width, max_change);
 931                         total = add + del;
 932                 }
 933                 show_name(options->file, prefix, name, len, reset, set);
 934                 fprintf(options->file, "%5d%s", added + deleted,
 935                                 added + deleted ? " " : "");
 936                 show_graph(options->file, '+', add, add_c, reset);
 937                 show_graph(options->file, '-', del, del_c, reset);
 938                 fprintf(options->file, "\n");
 939         }
 940         fprintf(options->file,
 941                "%s %d files changed, %d insertions(+), %d deletions(-)%s\n",
 942                set, total_files, adds, dels, reset);
 943 }
 944
 945 static void show_shortstats(struct diffstat_t* data, struct diff_options *options)
 946 {
 947         int i, adds = 0, dels = 0, total_files = data->nr;
 948
 949         if (data->nr == 0)
 950                 return;
 951
 952         for (i = 0; i < data->nr; i++) {
 953                 if (!data->files[i]->is_binary &&
 954                     !data->files[i]->is_unmerged) {
 955                         int added = data->files[i]->added;
 956                         int deleted= data->files[i]->deleted;
 957                         if (!data->files[i]->is_renamed &&
 958                             (added + deleted == 0)) {
 959                                 total_files--;
 960                         } else {
 961                                 adds += added;
 962                                 dels += deleted;
 963                         }
 964                 }
 965         }
 966         fprintf(options->file, " %d files changed, %d insertions(+), %d deletions(-)\n",
 967                total_files, adds, dels);
 968 }
 969
 970 static void show_numstat(struct diffstat_t* data, struct diff_options *options)
 971 {
 972         int i;
 973
 974         if (data->nr == 0)
 975                 return;
 976
 977         for (i = 0; i < data->nr; i++) {
 978                 struct diffstat_file *file = data->files[i];
 979
 980                 if (file->is_binary)
 981                         fprintf(options->file, "-\t-\t");
 982                 else
 983                         fprintf(options->file,
 984                                 "%d\t%d\t", file->added, file->deleted);
 985                 if (options->line_termination) {
 986                         fill_print_name(file);
 987                         if (!file->is_renamed)
 988                                 write_name_quoted(file->name, options->file,
 989                                                   options->line_termination);
 990                         else {
 991                                 fputs(file->print_name, options->file);
 992                                 putc(options->line_termination, options->file);
 993                         }
 994                 } else {
 995                         if (file->is_renamed) {
 996                                 putc('\0', options->file);
 997                                 write_name_quoted(file->from_name, options->file, '\0');
 998                         }
 999                         write_name_quoted(file->name, options->file, '\0');
1000                 }
1001         }
1002 }
1003
1004 struct dirstat_file {
1005         const char *name;
1006         unsigned long changed;
1007 };
1008
1009 struct dirstat_dir {
1010         struct dirstat_file *files;
1011         int alloc, nr, percent, cumulative;
1012 };
1013
1014 static long gather_dirstat(FILE *file, struct dirstat_dir *dir, unsigned long changed, const char *base, int baselen)
1015 {
1016         unsigned long this_dir = 0;
1017         unsigned int sources = 0;
1018
1019         while (dir->nr) {
1020                 struct dirstat_file *f = dir->files;
1021                 int namelen = strlen(f->name);
1022                 unsigned long this;
1023                 char *slash;
1024
1025                 if (namelen < baselen)
1026                         break;
1027                 if (memcmp(f->name, base, baselen))
1028                         break;
1029                 slash = strchr(f->name + baselen, '/');
1030                 if (slash) {
1031                         int newbaselen = slash + 1 - f->name;
1032                         this = gather_dirstat(file, dir, changed, f->name, newbaselen);
1033                         sources++;
1034                 } else {
1035                         this = f->changed;
1036                         dir->files++;
1037                         dir->nr--;
1038                         sources += 2;
1039                 }
1040                 this_dir += this;
1041         }
1042
1043         /*
1044          * We don't report dirstat's for
1045          *  - the top level
1046          *  - or cases where everything came from a single directory
1047          *    under this directory (sources == 1).
1048          */
1049         if (baselen && sources != 1) {
1050                 int permille = this_dir * 1000 / changed;
1051                 if (permille) {
1052                         int percent = permille / 10;
1053                         if (percent >= dir->percent) {
1054                                 fprintf(file, "%4d.%01d%% %.*s\n", percent, permille % 10, baselen, base);
1055                                 if (!dir->cumulative)
1056                                         return 0;
1057                         }
1058                 }
1059         }
1060         return this_dir;
1061 }
1062
1063 static int dirstat_compare(const void *_a, const void *_b)
1064 {
1065         const struct dirstat_file *a = _a;
1066         const struct dirstat_file *b = _b;
1067         return strcmp(a->name, b->name);
1068 }
1069
1070 static void show_dirstat(struct diff_options *options)
1071 {
1072         int i;
1073         unsigned long changed;
1074         struct dirstat_dir dir;
1075         struct diff_queue_struct *q = &diff_queued_diff;
1076
1077         dir.files = NULL;
1078         dir.alloc = 0;
1079         dir.nr = 0;
1080         dir.percent = options->dirstat_percent;
1081         dir.cumulative = options->output_format & DIFF_FORMAT_CUMULATIVE;
1082
1083         changed = 0;
1084         for (i = 0; i < q->nr; i++) {
1085                 struct diff_filepair *p = q->queue[i];
1086                 const char *name;
1087                 unsigned long copied, added, damage;
1088
1089                 name = p->one->path ? p->one->path : p->two->path;
1090
1091                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1092                         diff_populate_filespec(p->one, 0);
1093                         diff_populate_filespec(p->two, 0);
1094                         diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1095                                                &copied, &added);
1096                         diff_free_filespec_data(p->one);
1097                         diff_free_filespec_data(p->two);
1098                 } else if (DIFF_FILE_VALID(p->one)) {
1099                         diff_populate_filespec(p->one, 1);
1100                         copied = added = 0;
1101                         diff_free_filespec_data(p->one);
1102                 } else if (DIFF_FILE_VALID(p->two)) {
1103                         diff_populate_filespec(p->two, 1);
1104                         copied = 0;
1105                         added = p->two->size;
1106                         diff_free_filespec_data(p->two);
1107                 } else
1108                         continue;
1109
1110                 /*
1111                  * Original minus copied is the removed material,
1112                  * added is the new material.  They are both damages
1113                  * made to the preimage.
1114                  */
1115                 damage = (p->one->size - copied) + added;
1116
1117                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1118                 dir.files[dir.nr].name = name;
1119                 dir.files[dir.nr].changed = damage;
1120                 changed += damage;
1121                 dir.nr++;
1122         }
1123
1124         /* This can happen even with many files, if everything was renames */
1125         if (!changed)
1126                 return;
1127
1128         /* Show all directories with more than x% of the changes */
1129         qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1130         gather_dirstat(options->file, &dir, changed, "", 0);
1131 }
1132
1133 static void free_diffstat_info(struct diffstat_t *diffstat)
1134 {
1135         int i;
1136         for (i = 0; i < diffstat->nr; i++) {
1137                 struct diffstat_file *f = diffstat->files[i];
1138                 if (f->name != f->print_name)
1139                         free(f->print_name);
1140                 free(f->name);
1141                 free(f->from_name);
1142                 free(f);
1143         }
1144         free(diffstat->files);
1145 }
1146
1147 struct checkdiff_t {
1148         const char *filename;
1149         int lineno;
1150         struct diff_options *o;
1151         unsigned ws_rule;
1152         unsigned status;
1153         int trailing_blanks_start;
1154 };
1155
1156 static int is_conflict_marker(const char *line, unsigned long len)
1157 {
1158         char firstchar;
1159         int cnt;
1160
1161         if (len < 8)
1162                 return 0;
1163         firstchar = line[0];
1164         switch (firstchar) {
1165         case '=': case '>': case '<':
1166                 break;
1167         default:
1168                 return 0;
1169         }
1170         for (cnt = 1; cnt < 7; cnt++)
1171                 if (line[cnt] != firstchar)
1172                         return 0;
1173         /* line[0] thru line[6] are same as firstchar */
1174         if (firstchar == '=') {
1175                 /* divider between ours and theirs? */
1176                 if (len != 8 || line[7] != '\n')
1177                         return 0;
1178         } else if (len < 8 || !isspace(line[7])) {
1179                 /* not divider before ours nor after theirs */
1180                 return 0;
1181         }
1182         return 1;
1183 }
1184
1185 static void checkdiff_consume(void *priv, char *line, unsigned long len)
1186 {
1187         struct checkdiff_t *data = priv;
1188         int color_diff = DIFF_OPT_TST(data->o, COLOR_DIFF);
1189         const char *ws = diff_get_color(color_diff, DIFF_WHITESPACE);
1190         const char *reset = diff_get_color(color_diff, DIFF_RESET);
1191         const char *set = diff_get_color(color_diff, DIFF_FILE_NEW);
1192         char *err;
1193
1194         if (line[0] == '+') {
1195                 unsigned bad;
1196                 data->lineno++;
1197                 if (!ws_blank_line(line + 1, len - 1, data->ws_rule))
1198                         data->trailing_blanks_start = 0;
1199                 else if (!data->trailing_blanks_start)
1200                         data->trailing_blanks_start = data->lineno;
1201                 if (is_conflict_marker(line + 1, len - 1)) {
1202                         data->status |= 1;
1203                         fprintf(data->o->file,
1204                                 "%s:%d: leftover conflict marker\n",
1205                                 data->filename, data->lineno);
1206                 }
1207                 bad = ws_check(line + 1, len - 1, data->ws_rule);
1208                 if (!bad)
1209                         return;
1210                 data->status |= bad;
1211                 err = whitespace_error_string(bad);
1212                 fprintf(data->o->file, "%s:%d: %s.\n",
1213                         data->filename, data->lineno, err);
1214                 free(err);
1215                 emit_line(data->o->file, set, reset, line, 1);
1216                 ws_check_emit(line + 1, len - 1, data->ws_rule,
1217                               data->o->file, set, reset, ws);
1218         } else if (line[0] == ' ') {
1219                 data->lineno++;
1220                 data->trailing_blanks_start = 0;
1221         } else if (line[0] == '@') {
1222                 char *plus = strchr(line, '+');
1223                 if (plus)
1224                         data->lineno = strtol(plus, NULL, 10) - 1;
1225                 else
1226                         die("invalid diff");
1227                 data->trailing_blanks_start = 0;
1228         }
1229 }
1230
1231 static unsigned char *deflate_it(char *data,
1232                                  unsigned long size,
1233                                  unsigned long *result_size)
1234 {
1235         int bound;
1236         unsigned char *deflated;
1237         z_stream stream;
1238
1239         memset(&stream, 0, sizeof(stream));
1240         deflateInit(&stream, zlib_compression_level);
1241         bound = deflateBound(&stream, size);
1242         deflated = xmalloc(bound);
1243         stream.next_out = deflated;
1244         stream.avail_out = bound;
1245
1246         stream.next_in = (unsigned char *)data;
1247         stream.avail_in = size;
1248         while (deflate(&stream, Z_FINISH) == Z_OK)
1249                 ; /* nothing */
1250         deflateEnd(&stream);
1251         *result_size = stream.total_out;
1252         return deflated;
1253 }
1254
1255 static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two)
1256 {
1257         void *cp;
1258         void *delta;
1259         void *deflated;
1260         void *data;
1261         unsigned long orig_size;
1262         unsigned long delta_size;
1263         unsigned long deflate_size;
1264         unsigned long data_size;
1265
1266         /* We could do deflated delta, or we could do just deflated two,
1267          * whichever is smaller.
1268          */
1269         delta = NULL;
1270         deflated = deflate_it(two->ptr, two->size, &deflate_size);
1271         if (one->size && two->size) {
1272                 delta = diff_delta(one->ptr, one->size,
1273                                    two->ptr, two->size,
1274                                    &delta_size, deflate_size);
1275                 if (delta) {
1276                         void *to_free = delta;
1277                         orig_size = delta_size;
1278                         delta = deflate_it(delta, delta_size, &delta_size);
1279                         free(to_free);
1280                 }
1281         }
1282
1283         if (delta && delta_size < deflate_size) {
1284                 fprintf(file, "delta %lu\n", orig_size);
1285                 free(deflated);
1286                 data = delta;
1287                 data_size = delta_size;
1288         }
1289         else {
1290                 fprintf(file, "literal %lu\n", two->size);
1291                 free(delta);
1292                 data = deflated;
1293                 data_size = deflate_size;
1294         }
1295
1296         /* emit data encoded in base85 */
1297         cp = data;
1298         while (data_size) {
1299                 int bytes = (52 < data_size) ? 52 : data_size;
1300                 char line[70];
1301                 data_size -= bytes;
1302                 if (bytes <= 26)
1303                         line[0] = bytes + 'A' - 1;
1304                 else
1305                         line[0] = bytes - 26 + 'a' - 1;
1306                 encode_85(line + 1, cp, bytes);
1307                 cp = (char *) cp + bytes;
1308                 fputs(line, file);
1309                 fputc('\n', file);
1310         }
1311         fprintf(file, "\n");
1312         free(data);
1313 }
1314
1315 static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two)
1316 {
1317         fprintf(file, "GIT binary patch\n");
1318         emit_binary_diff_body(file, one, two);
1319         emit_binary_diff_body(file, two, one);
1320 }
1321
1322 static void setup_diff_attr_check(struct git_attr_check *check)
1323 {
1324         static struct git_attr *attr_diff;
1325
1326         if (!attr_diff) {
1327                 attr_diff = git_attr("diff", 4);
1328         }
1329         check[0].attr = attr_diff;
1330 }
1331
1332 static void diff_filespec_check_attr(struct diff_filespec *one)
1333 {
1334         struct git_attr_check attr_diff_check;
1335         int check_from_data = 0;
1336
1337         if (one->checked_attr)
1338                 return;
1339
1340         setup_diff_attr_check(&attr_diff_check);
1341         one->is_binary = 0;
1342         one->funcname_pattern_ident = NULL;
1343
1344         if (!git_checkattr(one->path, 1, &attr_diff_check)) {
1345                 const char *value;
1346
1347                 /* binaryness */
1348                 value = attr_diff_check.value;
1349                 if (ATTR_TRUE(value))
1350                         ;
1351                 else if (ATTR_FALSE(value))
1352                         one->is_binary = 1;
1353                 else
1354                         check_from_data = 1;
1355
1356                 /* funcname pattern ident */
1357                 if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
1358                         ;
1359                 else
1360                         one->funcname_pattern_ident = value;
1361         }
1362
1363         if (check_from_data) {
1364                 if (!one->data && DIFF_FILE_VALID(one))
1365                         diff_populate_filespec(one, 0);
1366
1367                 if (one->data)
1368                         one->is_binary = buffer_is_binary(one->data, one->size);
1369         }
1370 }
1371
1372 int diff_filespec_is_binary(struct diff_filespec *one)
1373 {
1374         diff_filespec_check_attr(one);
1375         return one->is_binary;
1376 }
1377
1378 static const char *funcname_pattern(const char *ident)
1379 {
1380         struct funcname_pattern *pp;
1381
1382         for (pp = funcname_pattern_list; pp; pp = pp->next)
1383                 if (!strcmp(ident, pp->name))
1384                         return pp->pattern;
1385         return NULL;
1386 }
1387
1388 static struct builtin_funcname_pattern {
1389         const char *name;
1390         const char *pattern;
1391 } builtin_funcname_pattern[] = {
1392         { "bibtex", "\\(@[a-zA-Z]\\{1,\\}[ \t]*{\\{0,1\\}[ \t]*[^ \t\"@',\\#}{~%]*\\).*$" },
1393         { "html", "^\\s*\\(<[Hh][1-6]\\s.*>.*\\)$" },
1394         { "java", "!^[  ]*\\(catch\\|do\\|for\\|if\\|instanceof\\|"
1395                         "new\\|return\\|switch\\|throw\\|while\\)\n"
1396                         "^[     ]*\\(\\([       ]*"
1397                         "[A-Za-z_][A-Za-z_0-9]*\\)\\{2,\\}"
1398                         "[      ]*([^;]*\\)$" },
1399         { "pascal", "^\\(\\(procedure\\|function\\|constructor\\|"
1400                         "destructor\\|interface\\|implementation\\|"
1401                         "initialization\\|finalization\\)[ \t]*.*\\)$"
1402                         "\\|"
1403                         "^\\(.*=[ \t]*\\(class\\|record\\).*\\)$"
1404                         },
1405         { "python", "^\\s*\\(\\(class\\|def\\)\\s.*\\)$" },
1406         { "ruby", "^\\s*\\(\\(class\\|module\\|def\\)\\s.*\\)$" },
1407         { "tex", "^\\(\\\\\\(\\(sub\\)*section\\|chapter\\|part\\)\\*\\{0,1\\}{.*\\)$" },
1408 };
1409
1410 static const char *diff_funcname_pattern(struct diff_filespec *one)
1411 {
1412         const char *ident, *pattern;
1413         int i;
1414
1415         diff_filespec_check_attr(one);
1416         ident = one->funcname_pattern_ident;
1417
1418         if (!ident)
1419                 /*
1420                  * If the config file has "funcname.default" defined, that
1421                  * regexp is used; otherwise NULL is returned and xemit uses
1422                  * the built-in default.
1423                  */
1424                 return funcname_pattern("default");
1425
1426         /* Look up custom "funcname.$ident" regexp from config. */
1427         pattern = funcname_pattern(ident);
1428         if (pattern)
1429                 return pattern;
1430
1431         /*
1432          * And define built-in fallback patterns here.  Note that
1433          * these can be overridden by the user's config settings.
1434          */
1435         for (i = 0; i < ARRAY_SIZE(builtin_funcname_pattern); i++)
1436                 if (!strcmp(ident, builtin_funcname_pattern[i].name))
1437                         return builtin_funcname_pattern[i].pattern;
1438
1439         return NULL;
1440 }
1441
1442 static void builtin_diff(const char *name_a,
1443                          const char *name_b,
1444                          struct diff_filespec *one,
1445                          struct diff_filespec *two,
1446                          const char *xfrm_msg,
1447                          struct diff_options *o,
1448                          int complete_rewrite)
1449 {
1450         mmfile_t mf1, mf2;
1451         const char *lbl[2];
1452         char *a_one, *b_two;
1453         const char *set = diff_get_color_opt(o, DIFF_METAINFO);
1454         const char *reset = diff_get_color_opt(o, DIFF_RESET);
1455
1456         a_one = quote_two(o->a_prefix, name_a + (*name_a == '/'));
1457         b_two = quote_two(o->b_prefix, name_b + (*name_b == '/'));
1458         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
1459         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
1460         fprintf(o->file, "%sdiff --git %s %s%s\n", set, a_one, b_two, reset);
1461         if (lbl[0][0] == '/') {
1462                 /* /dev/null */
1463                 fprintf(o->file, "%snew file mode %06o%s\n", set, two->mode, reset);
1464                 if (xfrm_msg && xfrm_msg[0])
1465                         fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
1466         }
1467         else if (lbl[1][0] == '/') {
1468                 fprintf(o->file, "%sdeleted file mode %06o%s\n", set, one->mode, reset);
1469                 if (xfrm_msg && xfrm_msg[0])
1470                         fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
1471         }
1472         else {
1473                 if (one->mode != two->mode) {
1474                         fprintf(o->file, "%sold mode %06o%s\n", set, one->mode, reset);
1475                         fprintf(o->file, "%snew mode %06o%s\n", set, two->mode, reset);
1476                 }
1477                 if (xfrm_msg && xfrm_msg[0])
1478                         fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
1479                 /*
1480                  * we do not run diff between different kind
1481                  * of objects.
1482                  */
1483                 if ((one->mode ^ two->mode) & S_IFMT)
1484                         goto free_ab_and_return;
1485                 if (complete_rewrite) {
1486                         emit_rewrite_diff(name_a, name_b, one, two, o);
1487                         o->found_changes = 1;
1488                         goto free_ab_and_return;
1489                 }
1490         }
1491
1492         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1493                 die("unable to read files to diff");
1494
1495         if (!DIFF_OPT_TST(o, TEXT) &&
1496             (diff_filespec_is_binary(one) || diff_filespec_is_binary(two))) {
1497                 /* Quite common confusing case */
1498                 if (mf1.size == mf2.size &&
1499                     !memcmp(mf1.ptr, mf2.ptr, mf1.size))
1500                         goto free_ab_and_return;
1501                 if (DIFF_OPT_TST(o, BINARY))
1502                         emit_binary_diff(o->file, &mf1, &mf2);
1503                 else
1504                         fprintf(o->file, "Binary files %s and %s differ\n",
1505                                 lbl[0], lbl[1]);
1506                 o->found_changes = 1;
1507         }
1508         else {
1509                 /* Crazy xdl interfaces.. */
1510                 const char *diffopts = getenv("GIT_DIFF_OPTS");
1511                 xpparam_t xpp;
1512                 xdemitconf_t xecfg;
1513                 xdemitcb_t ecb;
1514                 struct emit_callback ecbdata;
1515                 const char *funcname_pattern;
1516
1517                 funcname_pattern = diff_funcname_pattern(one);
1518                 if (!funcname_pattern)
1519                         funcname_pattern = diff_funcname_pattern(two);
1520
1521                 memset(&xecfg, 0, sizeof(xecfg));
1522                 memset(&ecbdata, 0, sizeof(ecbdata));
1523                 ecbdata.label_path = lbl;
1524                 ecbdata.color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
1525                 ecbdata.found_changesp = &o->found_changes;
1526                 ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
1527                 ecbdata.file = o->file;
1528                 xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
1529                 xecfg.ctxlen = o->context;
1530                 xecfg.flags = XDL_EMIT_FUNCNAMES;
1531                 if (funcname_pattern)
1532                         xdiff_set_find_func(&xecfg, funcname_pattern);
1533                 if (!diffopts)
1534                         ;
1535                 else if (!prefixcmp(diffopts, "--unified="))
1536                         xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
1537                 else if (!prefixcmp(diffopts, "-u"))
1538                         xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
1539                 if (DIFF_OPT_TST(o, COLOR_DIFF_WORDS)) {
1540                         ecbdata.diff_words =
1541                                 xcalloc(1, sizeof(struct diff_words_data));
1542                         ecbdata.diff_words->file = o->file;
1543                 }
1544                 xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
1545                               &xpp, &xecfg, &ecb);
1546                 if (DIFF_OPT_TST(o, COLOR_DIFF_WORDS))
1547                         free_diff_words_data(&ecbdata);
1548         }
1549
1550  free_ab_and_return:
1551         diff_free_filespec_data(one);
1552         diff_free_filespec_data(two);
1553         free(a_one);
1554         free(b_two);
1555         return;
1556 }
1557
1558 static void builtin_diffstat(const char *name_a, const char *name_b,
1559                              struct diff_filespec *one,
1560                              struct diff_filespec *two,
1561                              struct diffstat_t *diffstat,
1562                              struct diff_options *o,
1563                              int complete_rewrite)
1564 {
1565         mmfile_t mf1, mf2;
1566         struct diffstat_file *data;
1567
1568         data = diffstat_add(diffstat, name_a, name_b);
1569
1570         if (!one || !two) {
1571                 data->is_unmerged = 1;
1572                 return;
1573         }
1574         if (complete_rewrite) {
1575                 diff_populate_filespec(one, 0);
1576                 diff_populate_filespec(two, 0);
1577                 data->deleted = count_lines(one->data, one->size);
1578                 data->added = count_lines(two->data, two->size);
1579                 goto free_and_return;
1580         }
1581         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1582                 die("unable to read files to diff");
1583
1584         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
1585                 data->is_binary = 1;
1586                 data->added = mf2.size;
1587                 data->deleted = mf1.size;
1588         } else {
1589                 /* Crazy xdl interfaces.. */
1590                 xpparam_t xpp;
1591                 xdemitconf_t xecfg;
1592                 xdemitcb_t ecb;
1593
1594                 memset(&xecfg, 0, sizeof(xecfg));
1595                 xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
1596                 xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
1597                               &xpp, &xecfg, &ecb);
1598         }
1599
1600  free_and_return:
1601         diff_free_filespec_data(one);
1602         diff_free_filespec_data(two);
1603 }
1604
1605 static void builtin_checkdiff(const char *name_a, const char *name_b,
1606                               const char *attr_path,
1607                               struct diff_filespec *one,
1608                               struct diff_filespec *two,
1609                               struct diff_options *o)
1610 {
1611         mmfile_t mf1, mf2;
1612         struct checkdiff_t data;
1613
1614         if (!two)
1615                 return;
1616
1617         memset(&data, 0, sizeof(data));
1618         data.filename = name_b ? name_b : name_a;
1619         data.lineno = 0;
1620         data.o = o;
1621         data.ws_rule = whitespace_rule(attr_path);
1622
1623         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1624                 die("unable to read files to diff");
1625
1626         /*
1627          * All the other codepaths check both sides, but not checking
1628          * the "old" side here is deliberate.  We are checking the newly
1629          * introduced changes, and as long as the "new" side is text, we
1630          * can and should check what it introduces.
1631          */
1632         if (diff_filespec_is_binary(two))
1633                 goto free_and_return;
1634         else {
1635                 /* Crazy xdl interfaces.. */
1636                 xpparam_t xpp;
1637                 xdemitconf_t xecfg;
1638                 xdemitcb_t ecb;
1639
1640                 memset(&xecfg, 0, sizeof(xecfg));
1641                 xecfg.ctxlen = 1; /* at least one context line */
1642                 xpp.flags = XDF_NEED_MINIMAL;
1643                 xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
1644                               &xpp, &xecfg, &ecb);
1645
1646                 if ((data.ws_rule & WS_TRAILING_SPACE) &&
1647                     data.trailing_blanks_start) {
1648                         fprintf(o->file, "%s:%d: ends with blank lines.\n",
1649                                 data.filename, data.trailing_blanks_start);
1650                         data.status = 1; /* report errors */
1651                 }
1652         }
1653  free_and_return:
1654         diff_free_filespec_data(one);
1655         diff_free_filespec_data(two);
1656         if (data.status)
1657                 DIFF_OPT_SET(o, CHECK_FAILED);
1658 }
1659
1660 struct diff_filespec *alloc_filespec(const char *path)
1661 {
1662         int namelen = strlen(path);
1663         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
1664
1665         memset(spec, 0, sizeof(*spec));
1666         spec->path = (char *)(spec + 1);
1667         memcpy(spec->path, path, namelen+1);
1668         spec->count = 1;
1669         return spec;
1670 }
1671
1672 void free_filespec(struct diff_filespec *spec)
1673 {
1674         if (!--spec->count) {
1675                 diff_free_filespec_data(spec);
1676                 free(spec);
1677         }
1678 }
1679
1680 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
1681                    unsigned short mode)
1682 {
1683         if (mode) {
1684                 spec->mode = canon_mode(mode);
1685                 hashcpy(spec->sha1, sha1);
1686                 spec->sha1_valid = !is_null_sha1(sha1);
1687         }
1688 }
1689
1690 /*
1691  * Given a name and sha1 pair, if the index tells us the file in
1692  * the work tree has that object contents, return true, so that
1693  * prepare_temp_file() does not have to inflate and extract.
1694  */
1695 static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
1696 {
1697         struct cache_entry *ce;
1698         struct stat st;
1699         int pos, len;
1700
1701         /* We do not read the cache ourselves here, because the
1702          * benchmark with my previous version that always reads cache
1703          * shows that it makes things worse for diff-tree comparing
1704          * two linux-2.6 kernel trees in an already checked out work
1705          * tree.  This is because most diff-tree comparisons deal with
1706          * only a small number of files, while reading the cache is
1707          * expensive for a large project, and its cost outweighs the
1708          * savings we get by not inflating the object to a temporary
1709          * file.  Practically, this code only helps when we are used
1710          * by diff-cache --cached, which does read the cache before
1711          * calling us.
1712          */
1713         if (!active_cache)
1714                 return 0;
1715
1716         /* We want to avoid the working directory if our caller
1717          * doesn't need the data in a normal file, this system
1718          * is rather slow with its stat/open/mmap/close syscalls,
1719          * and the object is contained in a pack file.  The pack
1720          * is probably already open and will be faster to obtain
1721          * the data through than the working directory.  Loose
1722          * objects however would tend to be slower as they need
1723          * to be individually opened and inflated.
1724          */
1725         if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1, NULL))
1726                 return 0;
1727
1728         len = strlen(name);
1729         pos = cache_name_pos(name, len);
1730         if (pos < 0)
1731                 return 0;
1732         ce = active_cache[pos];
1733
1734         /*
1735          * This is not the sha1 we are looking for, or
1736          * unreusable because it is not a regular file.
1737          */
1738         if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
1739                 return 0;
1740
1741         /*
1742          * If ce matches the file in the work tree, we can reuse it.
1743          */
1744         if (ce_uptodate(ce) ||
1745             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
1746                 return 1;
1747
1748         return 0;
1749 }
1750
1751 static int populate_from_stdin(struct diff_filespec *s)
1752 {
1753         struct strbuf buf;
1754         size_t size = 0;
1755
1756         strbuf_init(&buf, 0);
1757         if (strbuf_read(&buf, 0, 0) < 0)
1758                 return error("error while reading from stdin %s",
1759                                      strerror(errno));
1760
1761         s->should_munmap = 0;
1762         s->data = strbuf_detach(&buf, &size);
1763         s->size = size;
1764         s->should_free = 1;
1765         return 0;
1766 }
1767
1768 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
1769 {
1770         int len;
1771         char *data = xmalloc(100);
1772         len = snprintf(data, 100,
1773                 "Subproject commit %s\n", sha1_to_hex(s->sha1));
1774         s->data = data;
1775         s->size = len;
1776         s->should_free = 1;
1777         if (size_only) {
1778                 s->data = NULL;
1779                 free(data);
1780         }
1781         return 0;
1782 }
1783
1784 /*
1785  * While doing rename detection and pickaxe operation, we may need to
1786  * grab the data for the blob (or file) for our own in-core comparison.
1787  * diff_filespec has data and size fields for this purpose.
1788  */
1789 int diff_populate_filespec(struct diff_filespec *s, int size_only)
1790 {
1791         int err = 0;
1792         if (!DIFF_FILE_VALID(s))
1793                 die("internal error: asking to populate invalid file.");
1794         if (S_ISDIR(s->mode))
1795                 return -1;
1796
1797         if (s->data)
1798                 return 0;
1799
1800         if (size_only && 0 < s->size)
1801                 return 0;
1802
1803         if (S_ISGITLINK(s->mode))
1804                 return diff_populate_gitlink(s, size_only);
1805
1806         if (!s->sha1_valid ||
1807             reuse_worktree_file(s->path, s->sha1, 0)) {
1808                 struct strbuf buf;
1809                 struct stat st;
1810                 int fd;
1811
1812                 if (!strcmp(s->path, "-"))
1813                         return populate_from_stdin(s);
1814
1815                 if (lstat(s->path, &st) < 0) {
1816                         if (errno == ENOENT) {
1817                         err_empty:
1818                                 err = -1;
1819                         empty:
1820                                 s->data = (char *)"";
1821                                 s->size = 0;
1822                                 return err;
1823                         }
1824                 }
1825                 s->size = xsize_t(st.st_size);
1826                 if (!s->size)
1827                         goto empty;
1828                 if (size_only)
1829                         return 0;
1830                 if (S_ISLNK(st.st_mode)) {
1831                         int ret;
1832                         s->data = xmalloc(s->size);
1833                         s->should_free = 1;
1834                         ret = readlink(s->path, s->data, s->size);
1835                         if (ret < 0) {
1836                                 free(s->data);
1837                                 goto err_empty;
1838                         }
1839                         return 0;
1840                 }
1841                 fd = open(s->path, O_RDONLY);
1842                 if (fd < 0)
1843                         goto err_empty;
1844                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
1845                 close(fd);
1846                 s->should_munmap = 1;
1847
1848                 /*
1849                  * Convert from working tree format to canonical git format
1850                  */
1851                 strbuf_init(&buf, 0);
1852                 if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
1853                         size_t size = 0;
1854                         munmap(s->data, s->size);
1855                         s->should_munmap = 0;
1856                         s->data = strbuf_detach(&buf, &size);
1857                         s->size = size;
1858                         s->should_free = 1;
1859                 }
1860         }
1861         else {
1862                 enum object_type type;
1863                 if (size_only)
1864                         type = sha1_object_info(s->sha1, &s->size);
1865                 else {
1866                         s->data = read_sha1_file(s->sha1, &type, &s->size);
1867                         s->should_free = 1;
1868                 }
1869         }
1870         return 0;
1871 }
1872
1873 void diff_free_filespec_blob(struct diff_filespec *s)
1874 {
1875         if (s->should_free)
1876                 free(s->data);
1877         else if (s->should_munmap)
1878                 munmap(s->data, s->size);
1879
1880         if (s->should_free || s->should_munmap) {
1881                 s->should_free = s->should_munmap = 0;
1882                 s->data = NULL;
1883         }
1884 }
1885
1886 void diff_free_filespec_data(struct diff_filespec *s)
1887 {
1888         diff_free_filespec_blob(s);
1889         free(s->cnt_data);
1890         s->cnt_data = NULL;
1891 }
1892
1893 static void prep_temp_blob(struct diff_tempfile *temp,
1894                            void *blob,
1895                            unsigned long size,
1896                            const unsigned char *sha1,
1897                            int mode)
1898 {
1899         int fd;
1900
1901         fd = git_mkstemp(temp->tmp_path, PATH_MAX, ".diff_XXXXXX");
1902         if (fd < 0)
1903                 die("unable to create temp-file: %s", strerror(errno));
1904         if (write_in_full(fd, blob, size) != size)
1905                 die("unable to write temp-file");
1906         close(fd);
1907         temp->name = temp->tmp_path;
1908         strcpy(temp->hex, sha1_to_hex(sha1));
1909         temp->hex[40] = 0;
1910         sprintf(temp->mode, "%06o", mode);
1911 }
1912
1913 static void prepare_temp_file(const char *name,
1914                               struct diff_tempfile *temp,
1915                               struct diff_filespec *one)
1916 {
1917         if (!DIFF_FILE_VALID(one)) {
1918         not_a_valid_file:
1919                 /* A '-' entry produces this for file-2, and
1920                  * a '+' entry produces this for file-1.
1921                  */
1922                 temp->name = "/dev/null";
1923                 strcpy(temp->hex, ".");
1924                 strcpy(temp->mode, ".");
1925                 return;
1926         }
1927
1928         if (!one->sha1_valid ||
1929             reuse_worktree_file(name, one->sha1, 1)) {
1930                 struct stat st;
1931                 if (lstat(name, &st) < 0) {
1932                         if (errno == ENOENT)
1933                                 goto not_a_valid_file;
1934                         die("stat(%s): %s", name, strerror(errno));
1935                 }
1936                 if (S_ISLNK(st.st_mode)) {
1937                         int ret;
1938                         char buf[PATH_MAX + 1]; /* ought to be SYMLINK_MAX */
1939                         size_t sz = xsize_t(st.st_size);
1940                         if (sizeof(buf) <= st.st_size)
1941                                 die("symlink too long: %s", name);
1942                         ret = readlink(name, buf, sz);
1943                         if (ret < 0)
1944                                 die("readlink(%s)", name);
1945                         prep_temp_blob(temp, buf, sz,
1946                                        (one->sha1_valid ?
1947                                         one->sha1 : null_sha1),
1948                                        (one->sha1_valid ?
1949                                         one->mode : S_IFLNK));
1950                 }
1951                 else {
1952                         /* we can borrow from the file in the work tree */
1953                         temp->name = name;
1954                         if (!one->sha1_valid)
1955                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
1956                         else
1957                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
1958                         /* Even though we may sometimes borrow the
1959                          * contents from the work tree, we always want
1960                          * one->mode.  mode is trustworthy even when
1961                          * !(one->sha1_valid), as long as
1962                          * DIFF_FILE_VALID(one).
1963                          */
1964                         sprintf(temp->mode, "%06o", one->mode);
1965                 }
1966                 return;
1967         }
1968         else {
1969                 if (diff_populate_filespec(one, 0))
1970                         die("cannot read data blob for %s", one->path);
1971                 prep_temp_blob(temp, one->data, one->size,
1972                                one->sha1, one->mode);
1973         }
1974 }
1975
1976 static void remove_tempfile(void)
1977 {
1978         int i;
1979
1980         for (i = 0; i < 2; i++)
1981                 if (diff_temp[i].name == diff_temp[i].tmp_path) {
1982                         unlink(diff_temp[i].name);
1983                         diff_temp[i].name = NULL;
1984                 }
1985 }
1986
1987 static void remove_tempfile_on_signal(int signo)
1988 {
1989         remove_tempfile();
1990         signal(SIGINT, SIG_DFL);
1991         raise(signo);
1992 }
1993
1994 /* An external diff command takes:
1995  *
1996  * diff-cmd name infile1 infile1-sha1 infile1-mode \
1997  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
1998  *
1999  */
2000 static void run_external_diff(const char *pgm,
2001                               const char *name,
2002                               const char *other,
2003                               struct diff_filespec *one,
2004                               struct diff_filespec *two,
2005                               const char *xfrm_msg,
2006                               int complete_rewrite)
2007 {
2008         const char *spawn_arg[10];
2009         struct diff_tempfile *temp = diff_temp;
2010         int retval;
2011         static int atexit_asked = 0;
2012         const char *othername;
2013         const char **arg = &spawn_arg[0];
2014
2015         othername = (other? other : name);
2016         if (one && two) {
2017                 prepare_temp_file(name, &temp[0], one);
2018                 prepare_temp_file(othername, &temp[1], two);
2019                 if (! atexit_asked &&
2020                     (temp[0].name == temp[0].tmp_path ||
2021                      temp[1].name == temp[1].tmp_path)) {
2022                         atexit_asked = 1;
2023                         atexit(remove_tempfile);
2024                 }
2025                 signal(SIGINT, remove_tempfile_on_signal);
2026         }
2027
2028         if (one && two) {
2029                 *arg++ = pgm;
2030                 *arg++ = name;
2031                 *arg++ = temp[0].name;
2032                 *arg++ = temp[0].hex;
2033                 *arg++ = temp[0].mode;
2034                 *arg++ = temp[1].name;
2035                 *arg++ = temp[1].hex;
2036                 *arg++ = temp[1].mode;
2037                 if (other) {
2038                         *arg++ = other;
2039                         *arg++ = xfrm_msg;
2040                 }
2041         } else {
2042                 *arg++ = pgm;
2043                 *arg++ = name;
2044         }
2045         *arg = NULL;
2046         fflush(NULL);
2047         retval = run_command_v_opt(spawn_arg, 0);
2048         remove_tempfile();
2049         if (retval) {
2050                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
2051                 exit(1);
2052         }
2053 }
2054
2055 static const char *external_diff_attr(const char *name)
2056 {
2057         struct git_attr_check attr_diff_check;
2058
2059         if (!name)
2060                 return NULL;
2061
2062         setup_diff_attr_check(&attr_diff_check);
2063         if (!git_checkattr(name, 1, &attr_diff_check)) {
2064                 const char *value = attr_diff_check.value;
2065                 if (!ATTR_TRUE(value) &&
2066                     !ATTR_FALSE(value) &&
2067                     !ATTR_UNSET(value)) {
2068                         struct ll_diff_driver *drv;
2069
2070                         for (drv = user_diff; drv; drv = drv->next)
2071                                 if (!strcmp(drv->name, value))
2072                                         return drv->cmd;
2073                 }
2074         }
2075         return NULL;
2076 }
2077
2078 static void run_diff_cmd(const char *pgm,
2079                          const char *name,
2080                          const char *other,
2081                          const char *attr_path,
2082                          struct diff_filespec *one,
2083                          struct diff_filespec *two,
2084                          const char *xfrm_msg,
2085                          struct diff_options *o,
2086                          int complete_rewrite)
2087 {
2088         if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
2089                 pgm = NULL;
2090         else {
2091                 const char *cmd = external_diff_attr(attr_path);
2092                 if (cmd)
2093                         pgm = cmd;
2094         }
2095
2096         if (pgm) {
2097                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
2098                                   complete_rewrite);
2099                 return;
2100         }
2101         if (one && two)
2102                 builtin_diff(name, other ? other : name,
2103                              one, two, xfrm_msg, o, complete_rewrite);
2104         else
2105                 fprintf(o->file, "* Unmerged path %s\n", name);
2106 }
2107
2108 static void diff_fill_sha1_info(struct diff_filespec *one)
2109 {
2110         if (DIFF_FILE_VALID(one)) {
2111                 if (!one->sha1_valid) {
2112                         struct stat st;
2113                         if (!strcmp(one->path, "-")) {
2114                                 hashcpy(one->sha1, null_sha1);
2115                                 return;
2116                         }
2117                         if (lstat(one->path, &st) < 0)
2118                                 die("stat %s", one->path);
2119                         if (index_path(one->sha1, one->path, &st, 0))
2120                                 die("cannot hash %s\n", one->path);
2121                 }
2122         }
2123         else
2124                 hashclr(one->sha1);
2125 }
2126
2127 static int similarity_index(struct diff_filepair *p)
2128 {
2129         return p->score * 100 / MAX_SCORE;
2130 }
2131
2132 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
2133 {
2134         /* Strip the prefix but do not molest /dev/null and absolute paths */
2135         if (*namep && **namep != '/')
2136                 *namep += prefix_length;
2137         if (*otherp && **otherp != '/')
2138                 *otherp += prefix_length;
2139 }
2140
2141 static void run_diff(struct diff_filepair *p, struct diff_options *o)
2142 {
2143         const char *pgm = external_diff();
2144         struct strbuf msg;
2145         char *xfrm_msg;
2146         struct diff_filespec *one = p->one;
2147         struct diff_filespec *two = p->two;
2148         const char *name;
2149         const char *other;
2150         const char *attr_path;
2151         int complete_rewrite = 0;
2152
2153         name  = p->one->path;
2154         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2155         attr_path = name;
2156         if (o->prefix_length)
2157                 strip_prefix(o->prefix_length, &name, &other);
2158
2159         if (DIFF_PAIR_UNMERGED(p)) {
2160                 run_diff_cmd(pgm, name, NULL, attr_path,
2161                              NULL, NULL, NULL, o, 0);
2162                 return;
2163         }
2164
2165         diff_fill_sha1_info(one);
2166         diff_fill_sha1_info(two);
2167
2168         strbuf_init(&msg, PATH_MAX * 2 + 300);
2169         switch (p->status) {
2170         case DIFF_STATUS_COPIED:
2171                 strbuf_addf(&msg, "similarity index %d%%", similarity_index(p));
2172                 strbuf_addstr(&msg, "\ncopy from ");
2173                 quote_c_style(name, &msg, NULL, 0);
2174                 strbuf_addstr(&msg, "\ncopy to ");
2175                 quote_c_style(other, &msg, NULL, 0);
2176                 strbuf_addch(&msg, '\n');
2177                 break;
2178         case DIFF_STATUS_RENAMED:
2179                 strbuf_addf(&msg, "similarity index %d%%", similarity_index(p));
2180                 strbuf_addstr(&msg, "\nrename from ");
2181                 quote_c_style(name, &msg, NULL, 0);
2182                 strbuf_addstr(&msg, "\nrename to ");
2183                 quote_c_style(other, &msg, NULL, 0);
2184                 strbuf_addch(&msg, '\n');
2185                 break;
2186         case DIFF_STATUS_MODIFIED:
2187                 if (p->score) {
2188                         strbuf_addf(&msg, "dissimilarity index %d%%\n",
2189                                         similarity_index(p));
2190                         complete_rewrite = 1;
2191                         break;
2192                 }
2193                 /* fallthru */
2194         default:
2195                 /* nothing */
2196                 ;
2197         }
2198
2199         if (hashcmp(one->sha1, two->sha1)) {
2200                 int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
2201
2202                 if (DIFF_OPT_TST(o, BINARY)) {
2203                         mmfile_t mf;
2204                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
2205                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
2206                                 abbrev = 40;
2207                 }
2208                 strbuf_addf(&msg, "index %.*s..%.*s",
2209                                 abbrev, sha1_to_hex(one->sha1),
2210                                 abbrev, sha1_to_hex(two->sha1));
2211                 if (one->mode == two->mode)
2212                         strbuf_addf(&msg, " %06o", one->mode);
2213                 strbuf_addch(&msg, '\n');
2214         }
2215
2216         if (msg.len)
2217                 strbuf_setlen(&msg, msg.len - 1);
2218         xfrm_msg = msg.len ? msg.buf : NULL;
2219
2220         if (!pgm &&
2221             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
2222             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
2223                 /* a filepair that changes between file and symlink
2224                  * needs to be split into deletion and creation.
2225                  */
2226                 struct diff_filespec *null = alloc_filespec(two->path);
2227                 run_diff_cmd(NULL, name, other, attr_path,
2228                              one, null, xfrm_msg, o, 0);
2229                 free(null);
2230                 null = alloc_filespec(one->path);
2231                 run_diff_cmd(NULL, name, other, attr_path,
2232                              null, two, xfrm_msg, o, 0);
2233                 free(null);
2234         }
2235         else
2236                 run_diff_cmd(pgm, name, other, attr_path,
2237                              one, two, xfrm_msg, o, complete_rewrite);
2238
2239         strbuf_release(&msg);
2240 }
2241
2242 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
2243                          struct diffstat_t *diffstat)
2244 {
2245         const char *name;
2246         const char *other;
2247         int complete_rewrite = 0;
2248
2249         if (DIFF_PAIR_UNMERGED(p)) {
2250                 /* unmerged */
2251                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, 0);
2252                 return;
2253         }
2254
2255         name = p->one->path;
2256         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2257
2258         if (o->prefix_length)
2259                 strip_prefix(o->prefix_length, &name, &other);
2260
2261         diff_fill_sha1_info(p->one);
2262         diff_fill_sha1_info(p->two);
2263
2264         if (p->status == DIFF_STATUS_MODIFIED && p->score)
2265                 complete_rewrite = 1;
2266         builtin_diffstat(name, other, p->one, p->two, diffstat, o, complete_rewrite);
2267 }
2268
2269 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
2270 {
2271         const char *name;
2272         const char *other;
2273         const char *attr_path;
2274
2275         if (DIFF_PAIR_UNMERGED(p)) {
2276                 /* unmerged */
2277                 return;
2278         }
2279
2280         name = p->one->path;
2281         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2282         attr_path = other ? other : name;
2283
2284         if (o->prefix_length)
2285                 strip_prefix(o->prefix_length, &name, &other);
2286
2287         diff_fill_sha1_info(p->one);
2288         diff_fill_sha1_info(p->two);
2289
2290         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
2291 }
2292
2293 void diff_setup(struct diff_options *options)
2294 {
2295         memset(options, 0, sizeof(*options));
2296
2297         options->file = stdout;
2298
2299         options->line_termination = '\n';
2300         options->break_opt = -1;
2301         options->rename_limit = -1;
2302         options->dirstat_percent = 3;
2303         options->context = 3;
2304
2305         options->change = diff_change;
2306         options->add_remove = diff_addremove;
2307         if (diff_use_color_default > 0)
2308                 DIFF_OPT_SET(options, COLOR_DIFF);
2309         else
2310                 DIFF_OPT_CLR(options, COLOR_DIFF);
2311         options->detect_rename = diff_detect_rename_default;
2312
2313         options->a_prefix = "a/";
2314         options->b_prefix = "b/";
2315 }
2316
2317 int diff_setup_done(struct diff_options *options)
2318 {
2319         int count = 0;
2320
2321         if (options->output_format & DIFF_FORMAT_NAME)
2322                 count++;
2323         if (options->output_format & DIFF_FORMAT_NAME_STATUS)
2324                 count++;
2325         if (options->output_format & DIFF_FORMAT_CHECKDIFF)
2326                 count++;
2327         if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
2328                 count++;
2329         if (count > 1)
2330                 die("--name-only, --name-status, --check and -s are mutually exclusive");
2331
2332         if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
2333                 options->detect_rename = DIFF_DETECT_COPY;
2334
2335         if (!DIFF_OPT_TST(options, RELATIVE_NAME))
2336                 options->prefix = NULL;
2337         if (options->prefix)
2338                 options->prefix_length = strlen(options->prefix);
2339         else
2340                 options->prefix_length = 0;
2341
2342         if (options->output_format & (DIFF_FORMAT_NAME |
2343                                       DIFF_FORMAT_NAME_STATUS |
2344                                       DIFF_FORMAT_CHECKDIFF |
2345                                       DIFF_FORMAT_NO_OUTPUT))
2346                 options->output_format &= ~(DIFF_FORMAT_RAW |
2347                                             DIFF_FORMAT_NUMSTAT |
2348                                             DIFF_FORMAT_DIFFSTAT |
2349                                             DIFF_FORMAT_SHORTSTAT |
2350                                             DIFF_FORMAT_DIRSTAT |
2351                                             DIFF_FORMAT_SUMMARY |
2352                                             DIFF_FORMAT_PATCH);
2353
2354         /*
2355          * These cases always need recursive; we do not drop caller-supplied
2356          * recursive bits for other formats here.
2357          */
2358         if (options->output_format & (DIFF_FORMAT_PATCH |
2359                                       DIFF_FORMAT_NUMSTAT |
2360                                       DIFF_FORMAT_DIFFSTAT |
2361                                       DIFF_FORMAT_SHORTSTAT |
2362                                       DIFF_FORMAT_DIRSTAT |
2363                                       DIFF_FORMAT_SUMMARY |
2364                                       DIFF_FORMAT_CHECKDIFF))
2365                 DIFF_OPT_SET(options, RECURSIVE);
2366         /*
2367          * Also pickaxe would not work very well if you do not say recursive
2368          */
2369         if (options->pickaxe)
2370                 DIFF_OPT_SET(options, RECURSIVE);
2371
2372         if (options->detect_rename && options->rename_limit < 0)
2373                 options->rename_limit = diff_rename_limit_default;
2374         if (options->setup & DIFF_SETUP_USE_CACHE) {
2375                 if (!active_cache)
2376                         /* read-cache does not die even when it fails
2377                          * so it is safe for us to do this here.  Also
2378                          * it does not smudge active_cache or active_nr
2379                          * when it fails, so we do not have to worry about
2380                          * cleaning it up ourselves either.
2381                          */
2382                         read_cache();
2383         }
2384         if (options->abbrev <= 0 || 40 < options->abbrev)
2385                 options->abbrev = 40; /* full */
2386
2387         /*
2388          * It does not make sense to show the first hit we happened
2389          * to have found.  It does not make sense not to return with
2390          * exit code in such a case either.
2391          */
2392         if (DIFF_OPT_TST(options, QUIET)) {
2393                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
2394                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
2395         }
2396
2397         /*
2398          * If we postprocess in diffcore, we cannot simply return
2399          * upon the first hit.  We need to run diff as usual.
2400          */
2401         if (options->pickaxe || options->filter)
2402                 DIFF_OPT_CLR(options, QUIET);
2403
2404         return 0;
2405 }
2406
2407 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
2408 {
2409         char c, *eq;
2410         int len;
2411
2412         if (*arg != '-')
2413                 return 0;
2414         c = *++arg;
2415         if (!c)
2416                 return 0;
2417         if (c == arg_short) {
2418                 c = *++arg;
2419                 if (!c)
2420                         return 1;
2421                 if (val && isdigit(c)) {
2422                         char *end;
2423                         int n = strtoul(arg, &end, 10);
2424                         if (*end)
2425                                 return 0;
2426                         *val = n;
2427                         return 1;
2428                 }
2429                 return 0;
2430         }
2431         if (c != '-')
2432                 return 0;
2433         arg++;
2434         eq = strchr(arg, '=');
2435         if (eq)
2436                 len = eq - arg;
2437         else
2438                 len = strlen(arg);
2439         if (!len || strncmp(arg, arg_long, len))
2440                 return 0;
2441         if (eq) {
2442                 int n;
2443                 char *end;
2444                 if (!isdigit(*++eq))
2445                         return 0;
2446                 n = strtoul(eq, &end, 10);
2447                 if (*end)
2448                         return 0;
2449                 *val = n;
2450         }
2451         return 1;
2452 }
2453
2454 static int diff_scoreopt_parse(const char *opt);
2455
2456 int diff_opt_parse(struct diff_options *options, const char **av, int ac)
2457 {
2458         const char *arg = av[0];
2459
2460         /* Output format options */
2461         if (!strcmp(arg, "-p") || !strcmp(arg, "-u"))
2462                 options->output_format |= DIFF_FORMAT_PATCH;
2463         else if (opt_arg(arg, 'U', "unified", &options->context))
2464                 options->output_format |= DIFF_FORMAT_PATCH;
2465         else if (!strcmp(arg, "--raw"))
2466                 options->output_format |= DIFF_FORMAT_RAW;
2467         else if (!strcmp(arg, "--patch-with-raw"))
2468                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW;
2469         else if (!strcmp(arg, "--numstat"))
2470                 options->output_format |= DIFF_FORMAT_NUMSTAT;
2471         else if (!strcmp(arg, "--shortstat"))
2472                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
2473         else if (opt_arg(arg, 'X', "dirstat", &options->dirstat_percent))
2474                 options->output_format |= DIFF_FORMAT_DIRSTAT;
2475         else if (!strcmp(arg, "--cumulative"))
2476                 options->output_format |= DIFF_FORMAT_CUMULATIVE;
2477         else if (!strcmp(arg, "--check"))
2478                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
2479         else if (!strcmp(arg, "--summary"))
2480                 options->output_format |= DIFF_FORMAT_SUMMARY;
2481         else if (!strcmp(arg, "--patch-with-stat"))
2482                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT;
2483         else if (!strcmp(arg, "--name-only"))
2484                 options->output_format |= DIFF_FORMAT_NAME;
2485         else if (!strcmp(arg, "--name-status"))
2486                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
2487         else if (!strcmp(arg, "-s"))
2488                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
2489         else if (!prefixcmp(arg, "--stat")) {
2490                 char *end;
2491                 int width = options->stat_width;
2492                 int name_width = options->stat_name_width;
2493                 arg += 6;
2494                 end = (char *)arg;
2495
2496                 switch (*arg) {
2497                 case '-':
2498                         if (!prefixcmp(arg, "-width="))
2499                                 width = strtoul(arg + 7, &end, 10);
2500                         else if (!prefixcmp(arg, "-name-width="))
2501                                 name_width = strtoul(arg + 12, &end, 10);
2502                         break;
2503                 case '=':
2504                         width = strtoul(arg+1, &end, 10);
2505                         if (*end == ',')
2506                                 name_width = strtoul(end+1, &end, 10);
2507                 }
2508
2509                 /* Important! This checks all the error cases! */
2510                 if (*end)
2511                         return 0;
2512                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
2513                 options->stat_name_width = name_width;
2514                 options->stat_width = width;
2515         }
2516
2517         /* renames options */
2518         else if (!prefixcmp(arg, "-B")) {
2519                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
2520                         return -1;
2521         }
2522         else if (!prefixcmp(arg, "-M")) {
2523                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
2524                         return -1;
2525                 options->detect_rename = DIFF_DETECT_RENAME;
2526         }
2527         else if (!prefixcmp(arg, "-C")) {
2528                 if (options->detect_rename == DIFF_DETECT_COPY)
2529                         DIFF_OPT_SET(options, FIND_COPIES_HARDER);
2530                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
2531                         return -1;
2532                 options->detect_rename = DIFF_DETECT_COPY;
2533         }
2534         else if (!strcmp(arg, "--no-renames"))
2535                 options->detect_rename = 0;
2536         else if (!strcmp(arg, "--relative"))
2537                 DIFF_OPT_SET(options, RELATIVE_NAME);
2538         else if (!prefixcmp(arg, "--relative=")) {
2539                 DIFF_OPT_SET(options, RELATIVE_NAME);
2540                 options->prefix = arg + 11;
2541         }
2542
2543         /* xdiff options */
2544         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
2545                 options->xdl_opts |= XDF_IGNORE_WHITESPACE;
2546         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
2547                 options->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
2548         else if (!strcmp(arg, "--ignore-space-at-eol"))
2549                 options->xdl_opts |= XDF_IGNORE_WHITESPACE_AT_EOL;
2550
2551         /* flags options */
2552         else if (!strcmp(arg, "--binary")) {
2553                 options->output_format |= DIFF_FORMAT_PATCH;
2554                 DIFF_OPT_SET(options, BINARY);
2555         }
2556         else if (!strcmp(arg, "--full-index"))
2557                 DIFF_OPT_SET(options, FULL_INDEX);
2558         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
2559                 DIFF_OPT_SET(options, TEXT);
2560         else if (!strcmp(arg, "-R"))
2561                 DIFF_OPT_SET(options, REVERSE_DIFF);
2562         else if (!strcmp(arg, "--find-copies-harder"))
2563                 DIFF_OPT_SET(options, FIND_COPIES_HARDER);
2564         else if (!strcmp(arg, "--follow"))
2565                 DIFF_OPT_SET(options, FOLLOW_RENAMES);
2566         else if (!strcmp(arg, "--color"))
2567                 DIFF_OPT_SET(options, COLOR_DIFF);
2568         else if (!strcmp(arg, "--no-color"))
2569                 DIFF_OPT_CLR(options, COLOR_DIFF);
2570         else if (!strcmp(arg, "--color-words"))
2571                 options->flags |= DIFF_OPT_COLOR_DIFF | DIFF_OPT_COLOR_DIFF_WORDS;
2572         else if (!strcmp(arg, "--exit-code"))
2573                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
2574         else if (!strcmp(arg, "--quiet"))
2575                 DIFF_OPT_SET(options, QUIET);
2576         else if (!strcmp(arg, "--ext-diff"))
2577                 DIFF_OPT_SET(options, ALLOW_EXTERNAL);
2578         else if (!strcmp(arg, "--no-ext-diff"))
2579                 DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
2580         else if (!strcmp(arg, "--ignore-submodules"))
2581                 DIFF_OPT_SET(options, IGNORE_SUBMODULES);
2582
2583         /* misc options */
2584         else if (!strcmp(arg, "-z"))
2585                 options->line_termination = 0;
2586         else if (!prefixcmp(arg, "-l"))
2587                 options->rename_limit = strtoul(arg+2, NULL, 10);
2588         else if (!prefixcmp(arg, "-S"))
2589                 options->pickaxe = arg + 2;
2590         else if (!strcmp(arg, "--pickaxe-all"))
2591                 options->pickaxe_opts = DIFF_PICKAXE_ALL;
2592         else if (!strcmp(arg, "--pickaxe-regex"))
2593                 options->pickaxe_opts = DIFF_PICKAXE_REGEX;
2594         else if (!prefixcmp(arg, "-O"))
2595                 options->orderfile = arg + 2;
2596         else if (!prefixcmp(arg, "--diff-filter="))
2597                 options->filter = arg + 14;
2598         else if (!strcmp(arg, "--abbrev"))
2599                 options->abbrev = DEFAULT_ABBREV;
2600         else if (!prefixcmp(arg, "--abbrev=")) {
2601                 options->abbrev = strtoul(arg + 9, NULL, 10);
2602                 if (options->abbrev < MINIMUM_ABBREV)
2603                         options->abbrev = MINIMUM_ABBREV;
2604                 else if (40 < options->abbrev)
2605                         options->abbrev = 40;
2606         }
2607         else if (!prefixcmp(arg, "--src-prefix="))
2608                 options->a_prefix = arg + 13;
2609         else if (!prefixcmp(arg, "--dst-prefix="))
2610                 options->b_prefix = arg + 13;
2611         else if (!strcmp(arg, "--no-prefix"))
2612                 options->a_prefix = options->b_prefix = "";
2613         else if (!prefixcmp(arg, "--output=")) {
2614                 options->file = fopen(arg + strlen("--output="), "w");
2615                 options->close_file = 1;
2616         } else
2617                 return 0;
2618         return 1;
2619 }
2620
2621 static int parse_num(const char **cp_p)
2622 {
2623         unsigned long num, scale;
2624         int ch, dot;
2625         const char *cp = *cp_p;
2626
2627         num = 0;
2628         scale = 1;
2629         dot = 0;
2630         for(;;) {
2631                 ch = *cp;
2632                 if ( !dot && ch == '.' ) {
2633                         scale = 1;
2634                         dot = 1;
2635                 } else if ( ch == '%' ) {
2636                         scale = dot ? scale*100 : 100;
2637                         cp++;   /* % is always at the end */
2638                         break;
2639                 } else if ( ch >= '0' && ch <= '9' ) {
2640                         if ( scale < 100000 ) {
2641                                 scale *= 10;
2642                                 num = (num*10) + (ch-'0');
2643                         }
2644                 } else {
2645                         break;
2646                 }
2647                 cp++;
2648         }
2649         *cp_p = cp;
2650
2651         /* user says num divided by scale and we say internally that
2652          * is MAX_SCORE * num / scale.
2653          */
2654         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
2655 }
2656
2657 static int diff_scoreopt_parse(const char *opt)
2658 {
2659         int opt1, opt2, cmd;
2660
2661         if (*opt++ != '-')
2662                 return -1;
2663         cmd = *opt++;
2664         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
2665                 return -1; /* that is not a -M, -C nor -B option */
2666
2667         opt1 = parse_num(&opt);
2668         if (cmd != 'B')
2669                 opt2 = 0;
2670         else {
2671                 if (*opt == 0)
2672                         opt2 = 0;
2673                 else if (*opt != '/')
2674                         return -1; /* we expect -B80/99 or -B80 */
2675                 else {
2676                         opt++;
2677                         opt2 = parse_num(&opt);
2678                 }
2679         }
2680         if (*opt != 0)
2681                 return -1;
2682         return opt1 | (opt2 << 16);
2683 }
2684
2685 struct diff_queue_struct diff_queued_diff;
2686
2687 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
2688 {
2689         if (queue->alloc <= queue->nr) {
2690                 queue->alloc = alloc_nr(queue->alloc);
2691                 queue->queue = xrealloc(queue->queue,
2692                                         sizeof(dp) * queue->alloc);
2693         }
2694         queue->queue[queue->nr++] = dp;
2695 }
2696
2697 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
2698                                  struct diff_filespec *one,
2699                                  struct diff_filespec *two)
2700 {
2701         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
2702         dp->one = one;
2703         dp->two = two;
2704         if (queue)
2705                 diff_q(queue, dp);
2706         return dp;
2707 }
2708
2709 void diff_free_filepair(struct diff_filepair *p)
2710 {
2711         free_filespec(p->one);
2712         free_filespec(p->two);
2713         free(p);
2714 }
2715
2716 /* This is different from find_unique_abbrev() in that
2717  * it stuffs the result with dots for alignment.
2718  */
2719 const char *diff_unique_abbrev(const unsigned char *sha1, int len)
2720 {
2721         int abblen;
2722         const char *abbrev;
2723         if (len == 40)
2724                 return sha1_to_hex(sha1);
2725
2726         abbrev = find_unique_abbrev(sha1, len);
2727         abblen = strlen(abbrev);
2728         if (abblen < 37) {
2729                 static char hex[41];
2730                 if (len < abblen && abblen <= len + 2)
2731                         sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
2732                 else
2733                         sprintf(hex, "%s...", abbrev);
2734                 return hex;
2735         }
2736         return sha1_to_hex(sha1);
2737 }
2738
2739 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
2740 {
2741         int line_termination = opt->line_termination;
2742         int inter_name_termination = line_termination ? '\t' : '\0';
2743
2744         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
2745                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
2746                         diff_unique_abbrev(p->one->sha1, opt->abbrev));
2747                 fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
2748         }
2749         if (p->score) {
2750                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
2751                         inter_name_termination);
2752         } else {
2753                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
2754         }
2755
2756         if (p->status == DIFF_STATUS_COPIED ||
2757             p->status == DIFF_STATUS_RENAMED) {
2758                 const char *name_a, *name_b;
2759                 name_a = p->one->path;
2760                 name_b = p->two->path;
2761                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2762                 write_name_quoted(name_a, opt->file, inter_name_termination);
2763                 write_name_quoted(name_b, opt->file, line_termination);
2764         } else {
2765                 const char *name_a, *name_b;
2766                 name_a = p->one->mode ? p->one->path : p->two->path;
2767                 name_b = NULL;
2768                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2769                 write_name_quoted(name_a, opt->file, line_termination);
2770         }
2771 }
2772
2773 int diff_unmodified_pair(struct diff_filepair *p)
2774 {
2775         /* This function is written stricter than necessary to support
2776          * the currently implemented transformers, but the idea is to
2777          * let transformers to produce diff_filepairs any way they want,
2778          * and filter and clean them up here before producing the output.
2779          */
2780         struct diff_filespec *one = p->one, *two = p->two;
2781
2782         if (DIFF_PAIR_UNMERGED(p))
2783                 return 0; /* unmerged is interesting */
2784
2785         /* deletion, addition, mode or type change
2786          * and rename are all interesting.
2787          */
2788         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
2789             DIFF_PAIR_MODE_CHANGED(p) ||
2790             strcmp(one->path, two->path))
2791                 return 0;
2792
2793         /* both are valid and point at the same path.  that is, we are
2794          * dealing with a change.
2795          */
2796         if (one->sha1_valid && two->sha1_valid &&
2797             !hashcmp(one->sha1, two->sha1))
2798                 return 1; /* no change */
2799         if (!one->sha1_valid && !two->sha1_valid)
2800                 return 1; /* both look at the same file on the filesystem. */
2801         return 0;
2802 }
2803
2804 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
2805 {
2806         if (diff_unmodified_pair(p))
2807                 return;
2808
2809         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2810             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2811                 return; /* no tree diffs in patch format */
2812
2813         run_diff(p, o);
2814 }
2815
2816 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
2817                             struct diffstat_t *diffstat)
2818 {
2819         if (diff_unmodified_pair(p))
2820                 return;
2821
2822         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2823             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2824                 return; /* no tree diffs in patch format */
2825
2826         run_diffstat(p, o, diffstat);
2827 }
2828
2829 static void diff_flush_checkdiff(struct diff_filepair *p,
2830                 struct diff_options *o)
2831 {
2832         if (diff_unmodified_pair(p))
2833                 return;
2834
2835         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2836             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2837                 return; /* no tree diffs in patch format */
2838
2839         run_checkdiff(p, o);
2840 }
2841
2842 int diff_queue_is_empty(void)
2843 {
2844         struct diff_queue_struct *q = &diff_queued_diff;
2845         int i;
2846         for (i = 0; i < q->nr; i++)
2847                 if (!diff_unmodified_pair(q->queue[i]))
2848                         return 0;
2849         return 1;
2850 }
2851
2852 #if DIFF_DEBUG
2853 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
2854 {
2855         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
2856                 x, one ? one : "",
2857                 s->path,
2858                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
2859                 s->mode,
2860                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
2861         fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
2862                 x, one ? one : "",
2863                 s->size, s->xfrm_flags);
2864 }
2865
2866 void diff_debug_filepair(const struct diff_filepair *p, int i)
2867 {
2868         diff_debug_filespec(p->one, i, "one");
2869         diff_debug_filespec(p->two, i, "two");
2870         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
2871                 p->score, p->status ? p->status : '?',
2872                 p->one->rename_used, p->broken_pair);
2873 }
2874
2875 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
2876 {
2877         int i;
2878         if (msg)
2879                 fprintf(stderr, "%s\n", msg);
2880         fprintf(stderr, "q->nr = %d\n", q->nr);
2881         for (i = 0; i < q->nr; i++) {
2882                 struct diff_filepair *p = q->queue[i];
2883                 diff_debug_filepair(p, i);
2884         }
2885 }
2886 #endif
2887
2888 static void diff_resolve_rename_copy(void)
2889 {
2890         int i;
2891         struct diff_filepair *p;
2892         struct diff_queue_struct *q = &diff_queued_diff;
2893
2894         diff_debug_queue("resolve-rename-copy", q);
2895
2896         for (i = 0; i < q->nr; i++) {
2897                 p = q->queue[i];
2898                 p->status = 0; /* undecided */
2899                 if (DIFF_PAIR_UNMERGED(p))
2900                         p->status = DIFF_STATUS_UNMERGED;
2901                 else if (!DIFF_FILE_VALID(p->one))
2902                         p->status = DIFF_STATUS_ADDED;
2903                 else if (!DIFF_FILE_VALID(p->two))
2904                         p->status = DIFF_STATUS_DELETED;
2905                 else if (DIFF_PAIR_TYPE_CHANGED(p))
2906                         p->status = DIFF_STATUS_TYPE_CHANGED;
2907
2908                 /* from this point on, we are dealing with a pair
2909                  * whose both sides are valid and of the same type, i.e.
2910                  * either in-place edit or rename/copy edit.
2911                  */
2912                 else if (DIFF_PAIR_RENAME(p)) {
2913                         /*
2914                          * A rename might have re-connected a broken
2915                          * pair up, causing the pathnames to be the
2916                          * same again. If so, that's not a rename at
2917                          * all, just a modification..
2918                          *
2919                          * Otherwise, see if this source was used for
2920                          * multiple renames, in which case we decrement
2921                          * the count, and call it a copy.
2922                          */
2923                         if (!strcmp(p->one->path, p->two->path))
2924                                 p->status = DIFF_STATUS_MODIFIED;
2925                         else if (--p->one->rename_used > 0)
2926                                 p->status = DIFF_STATUS_COPIED;
2927                         else
2928                                 p->status = DIFF_STATUS_RENAMED;
2929                 }
2930                 else if (hashcmp(p->one->sha1, p->two->sha1) ||
2931                          p->one->mode != p->two->mode ||
2932                          is_null_sha1(p->one->sha1))
2933                         p->status = DIFF_STATUS_MODIFIED;
2934                 else {
2935                         /* This is a "no-change" entry and should not
2936                          * happen anymore, but prepare for broken callers.
2937                          */
2938                         error("feeding unmodified %s to diffcore",
2939                               p->one->path);
2940                         p->status = DIFF_STATUS_UNKNOWN;
2941                 }
2942         }
2943         diff_debug_queue("resolve-rename-copy done", q);
2944 }
2945
2946 static int check_pair_status(struct diff_filepair *p)
2947 {
2948         switch (p->status) {
2949         case DIFF_STATUS_UNKNOWN:
2950                 return 0;
2951         case 0:
2952                 die("internal error in diff-resolve-rename-copy");
2953         default:
2954                 return 1;
2955         }
2956 }
2957
2958 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
2959 {
2960         int fmt = opt->output_format;
2961
2962         if (fmt & DIFF_FORMAT_CHECKDIFF)
2963                 diff_flush_checkdiff(p, opt);
2964         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
2965                 diff_flush_raw(p, opt);
2966         else if (fmt & DIFF_FORMAT_NAME) {
2967                 const char *name_a, *name_b;
2968                 name_a = p->two->path;
2969                 name_b = NULL;
2970                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2971                 write_name_quoted(name_a, opt->file, opt->line_termination);
2972         }
2973 }
2974
2975 static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
2976 {
2977         if (fs->mode)
2978                 fprintf(file, " %s mode %06o ", newdelete, fs->mode);
2979         else
2980                 fprintf(file, " %s ", newdelete);
2981         write_name_quoted(fs->path, file, '\n');
2982 }
2983
2984
2985 static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name)
2986 {
2987         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
2988                 fprintf(file, " mode change %06o => %06o%c", p->one->mode, p->two->mode,
2989                         show_name ? ' ' : '\n');
2990                 if (show_name) {
2991                         write_name_quoted(p->two->path, file, '\n');
2992                 }
2993         }
2994 }
2995
2996 static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p)
2997 {
2998         char *names = pprint_rename(p->one->path, p->two->path);
2999
3000         fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
3001         free(names);
3002         show_mode_change(file, p, 0);
3003 }
3004
3005 static void diff_summary(FILE *file, struct diff_filepair *p)
3006 {
3007         switch(p->status) {
3008         case DIFF_STATUS_DELETED:
3009                 show_file_mode_name(file, "delete", p->one);
3010                 break;
3011         case DIFF_STATUS_ADDED:
3012                 show_file_mode_name(file, "create", p->two);
3013                 break;
3014         case DIFF_STATUS_COPIED:
3015                 show_rename_copy(file, "copy", p);
3016                 break;
3017         case DIFF_STATUS_RENAMED:
3018                 show_rename_copy(file, "rename", p);
3019                 break;
3020         default:
3021                 if (p->score) {
3022                         fputs(" rewrite ", file);
3023                         write_name_quoted(p->two->path, file, ' ');
3024                         fprintf(file, "(%d%%)\n", similarity_index(p));
3025                 }
3026                 show_mode_change(file, p, !p->score);
3027                 break;
3028         }
3029 }
3030
3031 struct patch_id_t {
3032         SHA_CTX *ctx;
3033         int patchlen;
3034 };
3035
3036 static int remove_space(char *line, int len)
3037 {
3038         int i;
3039         char *dst = line;
3040         unsigned char c;
3041
3042         for (i = 0; i < len; i++)
3043                 if (!isspace((c = line[i])))
3044                         *dst++ = c;
3045
3046         return dst - line;
3047 }
3048
3049 static void patch_id_consume(void *priv, char *line, unsigned long len)
3050 {
3051         struct patch_id_t *data = priv;
3052         int new_len;
3053
3054         /* Ignore line numbers when computing the SHA1 of the patch */
3055         if (!prefixcmp(line, "@@ -"))
3056                 return;
3057
3058         new_len = remove_space(line, len);
3059
3060         SHA1_Update(data->ctx, line, new_len);
3061         data->patchlen += new_len;
3062 }
3063
3064 /* returns 0 upon success, and writes result into sha1 */
3065 static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
3066 {
3067         struct diff_queue_struct *q = &diff_queued_diff;
3068         int i;
3069         SHA_CTX ctx;
3070         struct patch_id_t data;
3071         char buffer[PATH_MAX * 4 + 20];
3072
3073         SHA1_Init(&ctx);
3074         memset(&data, 0, sizeof(struct patch_id_t));
3075         data.ctx = &ctx;
3076
3077         for (i = 0; i < q->nr; i++) {
3078                 xpparam_t xpp;
3079                 xdemitconf_t xecfg;
3080                 xdemitcb_t ecb;
3081                 mmfile_t mf1, mf2;
3082                 struct diff_filepair *p = q->queue[i];
3083                 int len1, len2;
3084
3085                 memset(&xecfg, 0, sizeof(xecfg));
3086                 if (p->status == 0)
3087                         return error("internal diff status error");
3088                 if (p->status == DIFF_STATUS_UNKNOWN)
3089                         continue;
3090                 if (diff_unmodified_pair(p))
3091                         continue;
3092                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3093                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3094                         continue;
3095                 if (DIFF_PAIR_UNMERGED(p))
3096                         continue;
3097
3098                 diff_fill_sha1_info(p->one);
3099                 diff_fill_sha1_info(p->two);
3100                 if (fill_mmfile(&mf1, p->one) < 0 ||
3101                                 fill_mmfile(&mf2, p->two) < 0)
3102                         return error("unable to read files to diff");
3103
3104                 len1 = remove_space(p->one->path, strlen(p->one->path));
3105                 len2 = remove_space(p->two->path, strlen(p->two->path));
3106                 if (p->one->mode == 0)
3107                         len1 = snprintf(buffer, sizeof(buffer),
3108                                         "diff--gita/%.*sb/%.*s"
3109                                         "newfilemode%06o"
3110                                         "---/dev/null"
3111                                         "+++b/%.*s",
3112                                         len1, p->one->path,
3113                                         len2, p->two->path,
3114                                         p->two->mode,
3115                                         len2, p->two->path);
3116                 else if (p->two->mode == 0)
3117                         len1 = snprintf(buffer, sizeof(buffer),
3118                                         "diff--gita/%.*sb/%.*s"
3119                                         "deletedfilemode%06o"
3120                                         "---a/%.*s"
3121                                         "+++/dev/null",
3122                                         len1, p->one->path,
3123                                         len2, p->two->path,
3124                                         p->one->mode,
3125                                         len1, p->one->path);
3126                 else
3127                         len1 = snprintf(buffer, sizeof(buffer),
3128                                         "diff--gita/%.*sb/%.*s"
3129                                         "---a/%.*s"
3130                                         "+++b/%.*s",
3131                                         len1, p->one->path,
3132                                         len2, p->two->path,
3133                                         len1, p->one->path,
3134                                         len2, p->two->path);
3135                 SHA1_Update(&ctx, buffer, len1);
3136
3137                 xpp.flags = XDF_NEED_MINIMAL;
3138                 xecfg.ctxlen = 3;
3139                 xecfg.flags = XDL_EMIT_FUNCNAMES;
3140                 xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
3141                               &xpp, &xecfg, &ecb);
3142         }
3143
3144         SHA1_Final(sha1, &ctx);
3145         return 0;
3146 }
3147
3148 int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
3149 {
3150         struct diff_queue_struct *q = &diff_queued_diff;
3151         int i;
3152         int result = diff_get_patch_id(options, sha1);
3153
3154         for (i = 0; i < q->nr; i++)
3155                 diff_free_filepair(q->queue[i]);
3156
3157         free(q->queue);
3158         q->queue = NULL;
3159         q->nr = q->alloc = 0;
3160
3161         return result;
3162 }
3163
3164 static int is_summary_empty(const struct diff_queue_struct *q)
3165 {
3166         int i;
3167
3168         for (i = 0; i < q->nr; i++) {
3169                 const struct diff_filepair *p = q->queue[i];
3170
3171                 switch (p->status) {
3172                 case DIFF_STATUS_DELETED:
3173                 case DIFF_STATUS_ADDED:
3174                 case DIFF_STATUS_COPIED:
3175                 case DIFF_STATUS_RENAMED:
3176                         return 0;
3177                 default:
3178                         if (p->score)
3179                                 return 0;
3180                         if (p->one->mode && p->two->mode &&
3181                             p->one->mode != p->two->mode)
3182                                 return 0;
3183                         break;
3184                 }
3185         }
3186         return 1;
3187 }
3188
3189 void diff_flush(struct diff_options *options)
3190 {
3191         struct diff_queue_struct *q = &diff_queued_diff;
3192         int i, output_format = options->output_format;
3193         int separator = 0;
3194
3195         /*
3196          * Order: raw, stat, summary, patch
3197          * or:    name/name-status/checkdiff (other bits clear)
3198          */
3199         if (!q->nr)
3200                 goto free_queue;
3201
3202         if (output_format & (DIFF_FORMAT_RAW |
3203                              DIFF_FORMAT_NAME |
3204                              DIFF_FORMAT_NAME_STATUS |
3205                              DIFF_FORMAT_CHECKDIFF)) {
3206                 for (i = 0; i < q->nr; i++) {
3207                         struct diff_filepair *p = q->queue[i];
3208                         if (check_pair_status(p))
3209                                 flush_one_pair(p, options);
3210                 }
3211                 separator++;
3212         }
3213
3214         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT)) {
3215                 struct diffstat_t diffstat;
3216
3217                 memset(&diffstat, 0, sizeof(struct diffstat_t));
3218                 for (i = 0; i < q->nr; i++) {
3219                         struct diff_filepair *p = q->queue[i];
3220                         if (check_pair_status(p))
3221                                 diff_flush_stat(p, options, &diffstat);
3222                 }
3223                 if (output_format & DIFF_FORMAT_NUMSTAT)
3224                         show_numstat(&diffstat, options);
3225                 if (output_format & DIFF_FORMAT_DIFFSTAT)
3226                         show_stats(&diffstat, options);
3227                 if (output_format & DIFF_FORMAT_SHORTSTAT)
3228                         show_shortstats(&diffstat, options);
3229                 free_diffstat_info(&diffstat);
3230                 separator++;
3231         }
3232         if (output_format & DIFF_FORMAT_DIRSTAT)
3233                 show_dirstat(options);
3234
3235         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
3236                 for (i = 0; i < q->nr; i++)
3237                         diff_summary(options->file, q->queue[i]);
3238                 separator++;
3239         }
3240
3241         if (output_format & DIFF_FORMAT_PATCH) {
3242                 if (separator) {
3243                         putc(options->line_termination, options->file);
3244                         if (options->stat_sep) {
3245                                 /* attach patch instead of inline */
3246                                 fputs(options->stat_sep, options->file);
3247                         }
3248                 }
3249
3250                 for (i = 0; i < q->nr; i++) {
3251                         struct diff_filepair *p = q->queue[i];
3252                         if (check_pair_status(p))
3253                                 diff_flush_patch(p, options);
3254                 }
3255         }
3256
3257         if (output_format & DIFF_FORMAT_CALLBACK)
3258                 options->format_callback(q, options, options->format_callback_data);
3259
3260         for (i = 0; i < q->nr; i++)
3261                 diff_free_filepair(q->queue[i]);
3262 free_queue:
3263         free(q->queue);
3264         q->queue = NULL;
3265         q->nr = q->alloc = 0;
3266         if (options->close_file)
3267                 fclose(options->file);
3268 }
3269
3270 static void diffcore_apply_filter(const char *filter)
3271 {
3272         int i;
3273         struct diff_queue_struct *q = &diff_queued_diff;
3274         struct diff_queue_struct outq;
3275         outq.queue = NULL;
3276         outq.nr = outq.alloc = 0;
3277
3278         if (!filter)
3279                 return;
3280
3281         if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
3282                 int found;
3283                 for (i = found = 0; !found && i < q->nr; i++) {
3284                         struct diff_filepair *p = q->queue[i];
3285                         if (((p->status == DIFF_STATUS_MODIFIED) &&
3286                              ((p->score &&
3287                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
3288                               (!p->score &&
3289                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
3290                             ((p->status != DIFF_STATUS_MODIFIED) &&
3291                              strchr(filter, p->status)))
3292                                 found++;
3293                 }
3294                 if (found)
3295                         return;
3296
3297                 /* otherwise we will clear the whole queue
3298                  * by copying the empty outq at the end of this
3299                  * function, but first clear the current entries
3300                  * in the queue.
3301                  */
3302                 for (i = 0; i < q->nr; i++)
3303                         diff_free_filepair(q->queue[i]);
3304         }
3305         else {
3306                 /* Only the matching ones */
3307                 for (i = 0; i < q->nr; i++) {
3308                         struct diff_filepair *p = q->queue[i];
3309
3310                         if (((p->status == DIFF_STATUS_MODIFIED) &&
3311                              ((p->score &&
3312                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
3313                               (!p->score &&
3314                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
3315                             ((p->status != DIFF_STATUS_MODIFIED) &&
3316                              strchr(filter, p->status)))
3317                                 diff_q(&outq, p);
3318                         else
3319                                 diff_free_filepair(p);
3320                 }
3321         }
3322         free(q->queue);
3323         *q = outq;
3324 }
3325
3326 /* Check whether two filespecs with the same mode and size are identical */
3327 static int diff_filespec_is_identical(struct diff_filespec *one,
3328                                       struct diff_filespec *two)
3329 {
3330         if (S_ISGITLINK(one->mode))
3331                 return 0;
3332         if (diff_populate_filespec(one, 0))
3333                 return 0;
3334         if (diff_populate_filespec(two, 0))
3335                 return 0;
3336         return !memcmp(one->data, two->data, one->size);
3337 }
3338
3339 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
3340 {
3341         int i;
3342         struct diff_queue_struct *q = &diff_queued_diff;
3343         struct diff_queue_struct outq;
3344         outq.queue = NULL;
3345         outq.nr = outq.alloc = 0;
3346
3347         for (i = 0; i < q->nr; i++) {
3348                 struct diff_filepair *p = q->queue[i];
3349
3350                 /*
3351                  * 1. Entries that come from stat info dirtyness
3352                  *    always have both sides (iow, not create/delete),
3353                  *    one side of the object name is unknown, with
3354                  *    the same mode and size.  Keep the ones that
3355                  *    do not match these criteria.  They have real
3356                  *    differences.
3357                  *
3358                  * 2. At this point, the file is known to be modified,
3359                  *    with the same mode and size, and the object
3360                  *    name of one side is unknown.  Need to inspect
3361                  *    the identical contents.
3362                  */
3363                 if (!DIFF_FILE_VALID(p->one) || /* (1) */
3364                     !DIFF_FILE_VALID(p->two) ||
3365                     (p->one->sha1_valid && p->two->sha1_valid) ||
3366                     (p->one->mode != p->two->mode) ||
3367                     diff_populate_filespec(p->one, 1) ||
3368                     diff_populate_filespec(p->two, 1) ||
3369                     (p->one->size != p->two->size) ||
3370                     !diff_filespec_is_identical(p->one, p->two)) /* (2) */
3371                         diff_q(&outq, p);
3372                 else {
3373                         /*
3374                          * The caller can subtract 1 from skip_stat_unmatch
3375                          * to determine how many paths were dirty only
3376                          * due to stat info mismatch.
3377                          */
3378                         if (!DIFF_OPT_TST(diffopt, NO_INDEX))
3379                                 diffopt->skip_stat_unmatch++;
3380                         diff_free_filepair(p);
3381                 }
3382         }
3383         free(q->queue);
3384         *q = outq;
3385 }
3386
3387 void diffcore_std(struct diff_options *options)
3388 {
3389         if (DIFF_OPT_TST(options, QUIET))
3390                 return;
3391
3392         if (options->skip_stat_unmatch && !DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3393                 diffcore_skip_stat_unmatch(options);
3394         if (options->break_opt != -1)
3395                 diffcore_break(options->break_opt);
3396         if (options->detect_rename)
3397                 diffcore_rename(options);
3398         if (options->break_opt != -1)
3399                 diffcore_merge_broken();
3400         if (options->pickaxe)
3401                 diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
3402         if (options->orderfile)
3403                 diffcore_order(options->orderfile);
3404         diff_resolve_rename_copy();
3405         diffcore_apply_filter(options->filter);
3406
3407         if (diff_queued_diff.nr)
3408                 DIFF_OPT_SET(options, HAS_CHANGES);
3409         else
3410                 DIFF_OPT_CLR(options, HAS_CHANGES);
3411 }
3412
3413 int diff_result_code(struct diff_options *opt, int status)
3414 {
3415         int result = 0;
3416         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
3417             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
3418                 return status;
3419         if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
3420             DIFF_OPT_TST(opt, HAS_CHANGES))
3421                 result |= 01;
3422         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
3423             DIFF_OPT_TST(opt, CHECK_FAILED))
3424                 result |= 02;
3425         return result;
3426 }
3427
3428 void diff_addremove(struct diff_options *options,
3429                     int addremove, unsigned mode,
3430                     const unsigned char *sha1,
3431                     const char *concatpath)
3432 {
3433         struct diff_filespec *one, *two;
3434
3435         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES) && S_ISGITLINK(mode))
3436                 return;
3437
3438         /* This may look odd, but it is a preparation for
3439          * feeding "there are unchanged files which should
3440          * not produce diffs, but when you are doing copy
3441          * detection you would need them, so here they are"
3442          * entries to the diff-core.  They will be prefixed
3443          * with something like '=' or '*' (I haven't decided
3444          * which but should not make any difference).
3445          * Feeding the same new and old to diff_change()
3446          * also has the same effect.
3447          * Before the final output happens, they are pruned after
3448          * merged into rename/copy pairs as appropriate.
3449          */
3450         if (DIFF_OPT_TST(options, REVERSE_DIFF))
3451                 addremove = (addremove == '+' ? '-' :
3452                              addremove == '-' ? '+' : addremove);
3453
3454         if (options->prefix &&
3455             strncmp(concatpath, options->prefix, options->prefix_length))
3456                 return;
3457
3458         one = alloc_filespec(concatpath);
3459         two = alloc_filespec(concatpath);
3460
3461         if (addremove != '+')
3462                 fill_filespec(one, sha1, mode);
3463         if (addremove != '-')
3464                 fill_filespec(two, sha1, mode);
3465
3466         diff_queue(&diff_queued_diff, one, two);
3467         DIFF_OPT_SET(options, HAS_CHANGES);
3468 }
3469
3470 void diff_change(struct diff_options *options,
3471                  unsigned old_mode, unsigned new_mode,
3472                  const unsigned char *old_sha1,
3473                  const unsigned char *new_sha1,
3474                  const char *concatpath)
3475 {
3476         struct diff_filespec *one, *two;
3477
3478         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES) && S_ISGITLINK(old_mode)
3479                         && S_ISGITLINK(new_mode))
3480                 return;
3481
3482         if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
3483                 unsigned tmp;
3484                 const unsigned char *tmp_c;
3485                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
3486                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
3487         }
3488
3489         if (options->prefix &&
3490             strncmp(concatpath, options->prefix, options->prefix_length))
3491                 return;
3492
3493         one = alloc_filespec(concatpath);
3494         two = alloc_filespec(concatpath);
3495         fill_filespec(one, old_sha1, old_mode);
3496         fill_filespec(two, new_sha1, new_mode);
3497
3498         diff_queue(&diff_queued_diff, one, two);
3499         DIFF_OPT_SET(options, HAS_CHANGES);
3500 }
3501
3502 void diff_unmerge(struct diff_options *options,
3503                   const char *path,
3504                   unsigned mode, const unsigned char *sha1)
3505 {
3506         struct diff_filespec *one, *two;
3507
3508         if (options->prefix &&
3509             strncmp(path, options->prefix, options->prefix_length))
3510                 return;
3511
3512         one = alloc_filespec(path);
3513         two = alloc_filespec(path);
3514         fill_filespec(one, sha1, mode);
3515         diff_queue(&diff_queued_diff, one, two)->is_unmerged = 1;
3516 }