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 int diff_use_color_default = -1;
  24 static const char *external_diff_cmd_cfg;
  25 int diff_auto_refresh_index = 1;
  26
  27 static char diff_colors[][COLOR_MAXLEN] = {
  28         "\033[m",       /* reset */
  29         "",             /* PLAIN (normal) */
  30         "\033[1m",      /* METAINFO (bold) */
  31         "\033[36m",     /* FRAGINFO (cyan) */
  32         "\033[31m",     /* OLD (red) */
  33         "\033[32m",     /* NEW (green) */
  34         "\033[33m",     /* COMMIT (yellow) */
  35         "\033[41m",     /* WHITESPACE (red background) */
  36 };
  37
  38 static int parse_diff_color_slot(const char *var, int ofs)
  39 {
  40         if (!strcasecmp(var+ofs, "plain"))
  41                 return DIFF_PLAIN;
  42         if (!strcasecmp(var+ofs, "meta"))
  43                 return DIFF_METAINFO;
  44         if (!strcasecmp(var+ofs, "frag"))
  45                 return DIFF_FRAGINFO;
  46         if (!strcasecmp(var+ofs, "old"))
  47                 return DIFF_FILE_OLD;
  48         if (!strcasecmp(var+ofs, "new"))
  49                 return DIFF_FILE_NEW;
  50         if (!strcasecmp(var+ofs, "commit"))
  51                 return DIFF_COMMIT;
  52         if (!strcasecmp(var+ofs, "whitespace"))
  53                 return DIFF_WHITESPACE;
  54         die("bad config variable '%s'", var);
  55 }
  56
  57 static struct ll_diff_driver {
  58         const char *name;
  59         struct ll_diff_driver *next;
  60         const char *cmd;
  61 } *user_diff, **user_diff_tail;
  62
  63 /*
  64  * Currently there is only "diff.<drivername>.command" variable;
  65  * because there are "diff.color.<slot>" variables, we are parsing
  66  * this in a bit convoluted way to allow low level diff driver
  67  * called "color".
  68  */
  69 static int parse_lldiff_command(const char *var, const char *ep, const char *value)
  70 {
  71         const char *name;
  72         int namelen;
  73         struct ll_diff_driver *drv;
  74
  75         name = var + 5;
  76         namelen = ep - name;
  77         for (drv = user_diff; drv; drv = drv->next)
  78                 if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
  79                         break;
  80         if (!drv) {
  81                 drv = xcalloc(1, sizeof(struct ll_diff_driver));
  82                 drv->name = xmemdupz(name, namelen);
  83                 if (!user_diff_tail)
  84                         user_diff_tail = &user_diff;
  85                 *user_diff_tail = drv;
  86                 user_diff_tail = &(drv->next);
  87         }
  88
  89         return git_config_string(&(drv->cmd), var, value);
  90 }
  91
  92 /*
  93  * 'diff.<what>.funcname' attribute can be specified in the configuration
  94  * to define a customized regexp to find the beginning of a function to
  95  * be used for hunk header lines of "diff -p" style output.
  96  */
  97 static struct funcname_pattern {
  98         char *name;
  99         char *pattern;
 100         struct funcname_pattern *next;
 101 } *funcname_pattern_list;
 102
 103 static int parse_funcname_pattern(const char *var, const char *ep, const char *value)
 104 {
 105         const char *name;
 106         int namelen;
 107         struct funcname_pattern *pp;
 108
 109         name = var + 5; /* "diff." */
 110         namelen = ep - name;
 111
 112         for (pp = funcname_pattern_list; pp; pp = pp->next)
 113                 if (!strncmp(pp->name, name, namelen) && !pp->name[namelen])
 114                         break;
 115         if (!pp) {
 116                 pp = xcalloc(1, sizeof(*pp));
 117                 pp->name = xmemdupz(name, namelen);
 118                 pp->next = funcname_pattern_list;
 119                 funcname_pattern_list = pp;
 120         }
 121         free(pp->pattern);
 122         pp->pattern = xstrdup(value);
 123         return 0;
 124 }
 125
 126 /*
 127  * These are to give UI layer defaults.
 128  * The core-level commands such as git-diff-files should
 129  * never be affected by the setting of diff.renames
 130  * the user happens to have in the configuration file.
 131  */
 132 int git_diff_ui_config(const char *var, const char *value, void *cb)
 133 {
 134         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 135                 diff_use_color_default = git_config_colorbool(var, value, -1);
 136                 return 0;
 137         }
 138         if (!strcmp(var, "diff.renames")) {
 139                 if (!value)
 140                         diff_detect_rename_default = DIFF_DETECT_RENAME;
 141                 else if (!strcasecmp(value, "copies") ||
 142                          !strcasecmp(value, "copy"))
 143                         diff_detect_rename_default = DIFF_DETECT_COPY;
 144                 else if (git_config_bool(var,value))
 145                         diff_detect_rename_default = DIFF_DETECT_RENAME;
 146                 return 0;
 147         }
 148         if (!strcmp(var, "diff.autorefreshindex")) {
 149                 diff_auto_refresh_index = git_config_bool(var, value);
 150                 return 0;
 151         }
 152         if (!strcmp(var, "diff.external"))
 153                 return git_config_string(&external_diff_cmd_cfg, var, value);
 154         if (!prefixcmp(var, "diff.")) {
 155                 const char *ep = strrchr(var, '.');
 156
 157                 if (ep != var + 4 && !strcmp(ep, ".command"))
 158                         return parse_lldiff_command(var, ep, value);
 159         }
 160
 161         return git_diff_basic_config(var, value, cb);
 162 }
 163
 164 int git_diff_basic_config(const char *var, const char *value, void *cb)
 165 {
 166         if (!strcmp(var, "diff.renamelimit")) {
 167                 diff_rename_limit_default = git_config_int(var, value);
 168                 return 0;
 169         }
 170
 171         if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
 172                 int slot = parse_diff_color_slot(var, 11);
 173                 if (!value)
 174                         return config_error_nonbool(var);
 175                 color_parse(value, var, diff_colors[slot]);
 176                 return 0;
 177         }
 178
 179         if (!prefixcmp(var, "diff.")) {
 180                 const char *ep = strrchr(var, '.');
 181                 if (ep != var + 4) {
 182                         if (!strcmp(ep, ".funcname")) {
 183                                 if (!value)
 184                                         return config_error_nonbool(var);
 185                                 return parse_funcname_pattern(var, ep, value);
 186                         }
 187                 }
 188         }
 189
 190         return git_color_default_config(var, value, cb);
 191 }
 192
 193 static char *quote_two(const char *one, const char *two)
 194 {
 195         int need_one = quote_c_style(one, NULL, NULL, 1);
 196         int need_two = quote_c_style(two, NULL, NULL, 1);
 197         struct strbuf res;
 198
 199         strbuf_init(&res, 0);
 200         if (need_one + need_two) {
 201                 strbuf_addch(&res, '"');
 202                 quote_c_style(one, &res, NULL, 1);
 203                 quote_c_style(two, &res, NULL, 1);
 204                 strbuf_addch(&res, '"');
 205         } else {
 206                 strbuf_addstr(&res, one);
 207                 strbuf_addstr(&res, two);
 208         }
 209         return strbuf_detach(&res, NULL);
 210 }
 211
 212 static const char *external_diff(void)
 213 {
 214         static const char *external_diff_cmd = NULL;
 215         static int done_preparing = 0;
 216
 217         if (done_preparing)
 218                 return external_diff_cmd;
 219         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 220         if (!external_diff_cmd)
 221                 external_diff_cmd = external_diff_cmd_cfg;
 222         done_preparing = 1;
 223         return external_diff_cmd;
 224 }
 225
 226 static struct diff_tempfile {
 227         const char *name; /* filename external diff should read from */
 228         char hex[41];
 229         char mode[10];
 230         char tmp_path[PATH_MAX];
 231 } diff_temp[2];
 232
 233 static int count_lines(const char *data, int size)
 234 {
 235         int count, ch, completely_empty = 1, nl_just_seen = 0;
 236         count = 0;
 237         while (0 < size--) {
 238                 ch = *data++;
 239                 if (ch == '\n') {
 240                         count++;
 241                         nl_just_seen = 1;
 242                         completely_empty = 0;
 243                 }
 244                 else {
 245                         nl_just_seen = 0;
 246                         completely_empty = 0;
 247                 }
 248         }
 249         if (completely_empty)
 250                 return 0;
 251         if (!nl_just_seen)
 252                 count++; /* no trailing newline */
 253         return count;
 254 }
 255
 256 static void print_line_count(FILE *file, int count)
 257 {
 258         switch (count) {
 259         case 0:
 260                 fprintf(file, "0,0");
 261                 break;
 262         case 1:
 263                 fprintf(file, "1");
 264                 break;
 265         default:
 266                 fprintf(file, "1,%d", count);
 267                 break;
 268         }
 269 }
 270
 271 static void copy_file_with_prefix(FILE *file,
 272                                   int prefix, const char *data, int size,
 273                                   const char *set, const char *reset)
 274 {
 275         int ch, nl_just_seen = 1;
 276         while (0 < size--) {
 277                 ch = *data++;
 278                 if (nl_just_seen) {
 279                         fputs(set, file);
 280                         putc(prefix, file);
 281                 }
 282                 if (ch == '\n') {
 283                         nl_just_seen = 1;
 284                         fputs(reset, file);
 285                 } else
 286                         nl_just_seen = 0;
 287                 putc(ch, file);
 288         }
 289         if (!nl_just_seen)
 290                 fprintf(file, "%s\n\\ No newline at end of file\n", reset);
 291 }
 292
 293 static void emit_rewrite_diff(const char *name_a,
 294                               const char *name_b,
 295                               struct diff_filespec *one,
 296                               struct diff_filespec *two,
 297                               struct diff_options *o)
 298 {
 299         int lc_a, lc_b;
 300         int color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
 301         const char *name_a_tab, *name_b_tab;
 302         const char *metainfo = diff_get_color(color_diff, DIFF_METAINFO);
 303         const char *fraginfo = diff_get_color(color_diff, DIFF_FRAGINFO);
 304         const char *old = diff_get_color(color_diff, DIFF_FILE_OLD);
 305         const char *new = diff_get_color(color_diff, DIFF_FILE_NEW);
 306         const char *reset = diff_get_color(color_diff, DIFF_RESET);
 307         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 308
 309         name_a += (*name_a == '/');
 310         name_b += (*name_b == '/');
 311         name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 312         name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 313
 314         strbuf_reset(&a_name);
 315         strbuf_reset(&b_name);
 316         quote_two_c_style(&a_name, o->a_prefix, name_a, 0);
 317         quote_two_c_style(&b_name, o->b_prefix, name_b, 0);
 318
 319         diff_populate_filespec(one, 0);
 320         diff_populate_filespec(two, 0);
 321         lc_a = count_lines(one->data, one->size);
 322         lc_b = count_lines(two->data, two->size);
 323         fprintf(o->file,
 324                 "%s--- %s%s%s\n%s+++ %s%s%s\n%s@@ -",
 325                 metainfo, a_name.buf, name_a_tab, reset,
 326                 metainfo, b_name.buf, name_b_tab, reset, fraginfo);
 327         print_line_count(o->file, lc_a);
 328         fprintf(o->file, " +");
 329         print_line_count(o->file, lc_b);
 330         fprintf(o->file, " @@%s\n", reset);
 331         if (lc_a)
 332                 copy_file_with_prefix(o->file, '-', one->data, one->size, old, reset);
 333         if (lc_b)
 334                 copy_file_with_prefix(o->file, '+', two->data, two->size, new, reset);
 335 }
 336
 337 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 338 {
 339         if (!DIFF_FILE_VALID(one)) {
 340                 mf->ptr = (char *)""; /* does not matter */
 341                 mf->size = 0;
 342                 return 0;
 343         }
 344         else if (diff_populate_filespec(one, 0))
 345                 return -1;
 346         mf->ptr = one->data;
 347         mf->size = one->size;
 348         return 0;
 349 }
 350
 351 struct diff_words_buffer {
 352         mmfile_t text;
 353         long alloc;
 354         long current; /* output pointer */
 355         int suppressed_newline;
 356 };
 357
 358 static void diff_words_append(char *line, unsigned long len,
 359                 struct diff_words_buffer *buffer)
 360 {
 361         if (buffer->text.size + len > buffer->alloc) {
 362                 buffer->alloc = (buffer->text.size + len) * 3 / 2;
 363                 buffer->text.ptr = xrealloc(buffer->text.ptr, buffer->alloc);
 364         }
 365         line++;
 366         len--;
 367         memcpy(buffer->text.ptr + buffer->text.size, line, len);
 368         buffer->text.size += len;
 369 }
 370
 371 struct diff_words_data {
 372         struct xdiff_emit_state xm;
 373         struct diff_words_buffer minus, plus;
 374         FILE *file;
 375 };
 376
 377 static void print_word(FILE *file, struct diff_words_buffer *buffer, int len, int color,
 378                 int suppress_newline)
 379 {
 380         const char *ptr;
 381         int eol = 0;
 382
 383         if (len == 0)
 384                 return;
 385
 386         ptr  = buffer->text.ptr + buffer->current;
 387         buffer->current += len;
 388
 389         if (ptr[len - 1] == '\n') {
 390                 eol = 1;
 391                 len--;
 392         }
 393
 394         fputs(diff_get_color(1, color), file);
 395         fwrite(ptr, len, 1, file);
 396         fputs(diff_get_color(1, DIFF_RESET), file);
 397
 398         if (eol) {
 399                 if (suppress_newline)
 400                         buffer->suppressed_newline = 1;
 401                 else
 402                         putc('\n', file);
 403         }
 404 }
 405
 406 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 407 {
 408         struct diff_words_data *diff_words = priv;
 409
 410         if (diff_words->minus.suppressed_newline) {
 411                 if (line[0] != '+')
 412                         putc('\n', diff_words->file);
 413                 diff_words->minus.suppressed_newline = 0;
 414         }
 415
 416         len--;
 417         switch (line[0]) {
 418                 case '-':
 419                         print_word(diff_words->file,
 420                                    &diff_words->minus, len, DIFF_FILE_OLD, 1);
 421                         break;
 422                 case '+':
 423                         print_word(diff_words->file,
 424                                    &diff_words->plus, len, DIFF_FILE_NEW, 0);
 425                         break;
 426                 case ' ':
 427                         print_word(diff_words->file,
 428                                    &diff_words->plus, len, DIFF_PLAIN, 0);
 429                         diff_words->minus.current += len;
 430                         break;
 431         }
 432 }
 433
 434 /* this executes the word diff on the accumulated buffers */
 435 static void diff_words_show(struct diff_words_data *diff_words)
 436 {
 437         xpparam_t xpp;
 438         xdemitconf_t xecfg;
 439         xdemitcb_t ecb;
 440         mmfile_t minus, plus;
 441         int i;
 442
 443         memset(&xecfg, 0, sizeof(xecfg));
 444         minus.size = diff_words->minus.text.size;
 445         minus.ptr = xmalloc(minus.size);
 446         memcpy(minus.ptr, diff_words->minus.text.ptr, minus.size);
 447         for (i = 0; i < minus.size; i++)
 448                 if (isspace(minus.ptr[i]))
 449                         minus.ptr[i] = '\n';
 450         diff_words->minus.current = 0;
 451
 452         plus.size = diff_words->plus.text.size;
 453         plus.ptr = xmalloc(plus.size);
 454         memcpy(plus.ptr, diff_words->plus.text.ptr, plus.size);
 455         for (i = 0; i < plus.size; i++)
 456                 if (isspace(plus.ptr[i]))
 457                         plus.ptr[i] = '\n';
 458         diff_words->plus.current = 0;
 459
 460         xpp.flags = XDF_NEED_MINIMAL;
 461         xecfg.ctxlen = diff_words->minus.alloc + diff_words->plus.alloc;
 462         ecb.outf = xdiff_outf;
 463         ecb.priv = diff_words;
 464         diff_words->xm.consume = fn_out_diff_words_aux;
 465         xdi_diff(&minus, &plus, &xpp, &xecfg, &ecb);
 466
 467         free(minus.ptr);
 468         free(plus.ptr);
 469         diff_words->minus.text.size = diff_words->plus.text.size = 0;
 470
 471         if (diff_words->minus.suppressed_newline) {
 472                 putc('\n', diff_words->file);
 473                 diff_words->minus.suppressed_newline = 0;
 474         }
 475 }
 476
 477 typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 478
 479 struct emit_callback {
 480         struct xdiff_emit_state xm;
 481         int nparents, color_diff;
 482         unsigned ws_rule;
 483         sane_truncate_fn truncate;
 484         const char **label_path;
 485         struct diff_words_data *diff_words;
 486         int *found_changesp;
 487         FILE *file;
 488 };
 489
 490 static void free_diff_words_data(struct emit_callback *ecbdata)
 491 {
 492         if (ecbdata->diff_words) {
 493                 /* flush buffers */
 494                 if (ecbdata->diff_words->minus.text.size ||
 495                                 ecbdata->diff_words->plus.text.size)
 496                         diff_words_show(ecbdata->diff_words);
 497
 498                 free (ecbdata->diff_words->minus.text.ptr);
 499                 free (ecbdata->diff_words->plus.text.ptr);
 500                 free(ecbdata->diff_words);
 501                 ecbdata->diff_words = NULL;
 502         }
 503 }
 504
 505 const char *diff_get_color(int diff_use_color, enum color_diff ix)
 506 {
 507         if (diff_use_color)
 508                 return diff_colors[ix];
 509         return "";
 510 }
 511
 512 static void emit_line(FILE *file, const char *set, const char *reset, const char *line, int len)
 513 {
 514         int has_trailing_newline, has_trailing_carriage_return;
 515
 516         has_trailing_newline = (len > 0 && line[len-1] == '\n');
 517         if (has_trailing_newline)
 518                 len--;
 519         has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 520         if (has_trailing_carriage_return)
 521                 len--;
 522
 523         fputs(set, file);
 524         fwrite(line, len, 1, file);
 525         fputs(reset, file);
 526         if (has_trailing_carriage_return)
 527                 fputc('\r', file);
 528         if (has_trailing_newline)
 529                 fputc('\n', file);
 530 }
 531
 532 static void emit_add_line(const char *reset, struct emit_callback *ecbdata, const char *line, int len)
 533 {
 534         const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 535         const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
 536
 537         if (!*ws)
 538                 emit_line(ecbdata->file, set, reset, line, len);
 539         else {
 540                 /* Emit just the prefix, then the rest. */
 541                 emit_line(ecbdata->file, set, reset, line, ecbdata->nparents);
 542                 ws_check_emit(line + ecbdata->nparents,
 543                               len - ecbdata->nparents, ecbdata->ws_rule,
 544                               ecbdata->file, set, reset, ws);
 545         }
 546 }
 547
 548 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
 549 {
 550         const char *cp;
 551         unsigned long allot;
 552         size_t l = len;
 553
 554         if (ecb->truncate)
 555                 return ecb->truncate(line, len);
 556         cp = line;
 557         allot = l;
 558         while (0 < l) {
 559                 (void) utf8_width(&cp, &l);
 560                 if (!cp)
 561                         break; /* truncated in the middle? */
 562         }
 563         return allot - l;
 564 }
 565
 566 static void fn_out_consume(void *priv, char *line, unsigned long len)
 567 {
 568         int i;
 569         int color;
 570         struct emit_callback *ecbdata = priv;
 571         const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
 572         const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
 573         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 574
 575         *(ecbdata->found_changesp) = 1;
 576
 577         if (ecbdata->label_path[0]) {
 578                 const char *name_a_tab, *name_b_tab;
 579
 580                 name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
 581                 name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
 582
 583                 fprintf(ecbdata->file, "%s--- %s%s%s\n",
 584                         meta, ecbdata->label_path[0], reset, name_a_tab);
 585                 fprintf(ecbdata->file, "%s+++ %s%s%s\n",
 586                         meta, ecbdata->label_path[1], reset, name_b_tab);
 587                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
 588         }
 589
 590         /* This is not really necessary for now because
 591          * this codepath only deals with two-way diffs.
 592          */
 593         for (i = 0; i < len && line[i] == '@'; i++)
 594                 ;
 595         if (2 <= i && i < len && line[i] == ' ') {
 596                 ecbdata->nparents = i - 1;
 597                 len = sane_truncate_line(ecbdata, line, len);
 598                 emit_line(ecbdata->file,
 599                           diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO),
 600                           reset, line, len);
 601                 if (line[len-1] != '\n')
 602                         putc('\n', ecbdata->file);
 603                 return;
 604         }
 605
 606         if (len < ecbdata->nparents) {
 607                 emit_line(ecbdata->file, reset, reset, line, len);
 608                 return;
 609         }
 610
 611         color = DIFF_PLAIN;
 612         if (ecbdata->diff_words && ecbdata->nparents != 1)
 613                 /* fall back to normal diff */
 614                 free_diff_words_data(ecbdata);
 615         if (ecbdata->diff_words) {
 616                 if (line[0] == '-') {
 617                         diff_words_append(line, len,
 618                                           &ecbdata->diff_words->minus);
 619                         return;
 620                 } else if (line[0] == '+') {
 621                         diff_words_append(line, len,
 622                                           &ecbdata->diff_words->plus);
 623                         return;
 624                 }
 625                 if (ecbdata->diff_words->minus.text.size ||
 626                     ecbdata->diff_words->plus.text.size)
 627                         diff_words_show(ecbdata->diff_words);
 628                 line++;
 629                 len--;
 630                 emit_line(ecbdata->file, plain, reset, line, len);
 631                 return;
 632         }
 633         for (i = 0; i < ecbdata->nparents && len; i++) {
 634                 if (line[i] == '-')
 635                         color = DIFF_FILE_OLD;
 636                 else if (line[i] == '+')
 637                         color = DIFF_FILE_NEW;
 638         }
 639
 640         if (color != DIFF_FILE_NEW) {
 641                 emit_line(ecbdata->file,
 642                           diff_get_color(ecbdata->color_diff, color),
 643                           reset, line, len);
 644                 return;
 645         }
 646         emit_add_line(reset, ecbdata, line, len);
 647 }
 648
 649 static char *pprint_rename(const char *a, const char *b)
 650 {
 651         const char *old = a;
 652         const char *new = b;
 653         struct strbuf name;
 654         int pfx_length, sfx_length;
 655         int len_a = strlen(a);
 656         int len_b = strlen(b);
 657         int a_midlen, b_midlen;
 658         int qlen_a = quote_c_style(a, NULL, NULL, 0);
 659         int qlen_b = quote_c_style(b, NULL, NULL, 0);
 660
 661         strbuf_init(&name, 0);
 662         if (qlen_a || qlen_b) {
 663                 quote_c_style(a, &name, NULL, 0);
 664                 strbuf_addstr(&name, " => ");
 665                 quote_c_style(b, &name, NULL, 0);
 666                 return strbuf_detach(&name, NULL);
 667         }
 668
 669         /* Find common prefix */
 670         pfx_length = 0;
 671         while (*old && *new && *old == *new) {
 672                 if (*old == '/')
 673                         pfx_length = old - a + 1;
 674                 old++;
 675                 new++;
 676         }
 677
 678         /* Find common suffix */
 679         old = a + len_a;
 680         new = b + len_b;
 681         sfx_length = 0;
 682         while (a <= old && b <= new && *old == *new) {
 683                 if (*old == '/')
 684                         sfx_length = len_a - (old - a);
 685                 old--;
 686                 new--;
 687         }
 688
 689         /*
 690          * pfx{mid-a => mid-b}sfx
 691          * {pfx-a => pfx-b}sfx
 692          * pfx{sfx-a => sfx-b}
 693          * name-a => name-b
 694          */
 695         a_midlen = len_a - pfx_length - sfx_length;
 696         b_midlen = len_b - pfx_length - sfx_length;
 697         if (a_midlen < 0)
 698                 a_midlen = 0;
 699         if (b_midlen < 0)
 700                 b_midlen = 0;
 701
 702         strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
 703         if (pfx_length + sfx_length) {
 704                 strbuf_add(&name, a, pfx_length);
 705                 strbuf_addch(&name, '{');
 706         }
 707         strbuf_add(&name, a + pfx_length, a_midlen);
 708         strbuf_addstr(&name, " => ");
 709         strbuf_add(&name, b + pfx_length, b_midlen);
 710         if (pfx_length + sfx_length) {
 711                 strbuf_addch(&name, '}');
 712                 strbuf_add(&name, a + len_a - sfx_length, sfx_length);
 713         }
 714         return strbuf_detach(&name, NULL);
 715 }
 716
 717 struct diffstat_t {
 718         struct xdiff_emit_state xm;
 719
 720         int nr;
 721         int alloc;
 722         struct diffstat_file {
 723                 char *from_name;
 724                 char *name;
 725                 char *print_name;
 726                 unsigned is_unmerged:1;
 727                 unsigned is_binary:1;
 728                 unsigned is_renamed:1;
 729                 unsigned int added, deleted;
 730         } **files;
 731 };
 732
 733 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
 734                                           const char *name_a,
 735                                           const char *name_b)
 736 {
 737         struct diffstat_file *x;
 738         x = xcalloc(sizeof (*x), 1);
 739         if (diffstat->nr == diffstat->alloc) {
 740                 diffstat->alloc = alloc_nr(diffstat->alloc);
 741                 diffstat->files = xrealloc(diffstat->files,
 742                                 diffstat->alloc * sizeof(x));
 743         }
 744         diffstat->files[diffstat->nr++] = x;
 745         if (name_b) {
 746                 x->from_name = xstrdup(name_a);
 747                 x->name = xstrdup(name_b);
 748                 x->is_renamed = 1;
 749         }
 750         else {
 751                 x->from_name = NULL;
 752                 x->name = xstrdup(name_a);
 753         }
 754         return x;
 755 }
 756
 757 static void diffstat_consume(void *priv, char *line, unsigned long len)
 758 {
 759         struct diffstat_t *diffstat = priv;
 760         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
 761
 762         if (line[0] == '+')
 763                 x->added++;
 764         else if (line[0] == '-')
 765                 x->deleted++;
 766 }
 767
 768 const char mime_boundary_leader[] = "------------";
 769
 770 static int scale_linear(int it, int width, int max_change)
 771 {
 772         /*
 773          * make sure that at least one '-' is printed if there were deletions,
 774          * and likewise for '+'.
 775          */
 776         if (max_change < 2)
 777                 return it;
 778         return ((it - 1) * (width - 1) + max_change - 1) / (max_change - 1);
 779 }
 780
 781 static void show_name(FILE *file,
 782                       const char *prefix, const char *name, int len,
 783                       const char *reset, const char *set)
 784 {
 785         fprintf(file, " %s%s%-*s%s |", set, prefix, len, name, reset);
 786 }
 787
 788 static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
 789 {
 790         if (cnt <= 0)
 791                 return;
 792         fprintf(file, "%s", set);
 793         while (cnt--)
 794                 putc(ch, file);
 795         fprintf(file, "%s", reset);
 796 }
 797
 798 static void fill_print_name(struct diffstat_file *file)
 799 {
 800         char *pname;
 801
 802         if (file->print_name)
 803                 return;
 804
 805         if (!file->is_renamed) {
 806                 struct strbuf buf;
 807                 strbuf_init(&buf, 0);
 808                 if (quote_c_style(file->name, &buf, NULL, 0)) {
 809                         pname = strbuf_detach(&buf, NULL);
 810                 } else {
 811                         pname = file->name;
 812                         strbuf_release(&buf);
 813                 }
 814         } else {
 815                 pname = pprint_rename(file->from_name, file->name);
 816         }
 817         file->print_name = pname;
 818 }
 819
 820 static void show_stats(struct diffstat_t* data, struct diff_options *options)
 821 {
 822         int i, len, add, del, total, adds = 0, dels = 0;
 823         int max_change = 0, max_len = 0;
 824         int total_files = data->nr;
 825         int width, name_width;
 826         const char *reset, *set, *add_c, *del_c;
 827
 828         if (data->nr == 0)
 829                 return;
 830
 831         width = options->stat_width ? options->stat_width : 80;
 832         name_width = options->stat_name_width ? options->stat_name_width : 50;
 833
 834         /* Sanity: give at least 5 columns to the graph,
 835          * but leave at least 10 columns for the name.
 836          */
 837         if (width < 25)
 838                 width = 25;
 839         if (name_width < 10)
 840                 name_width = 10;
 841         else if (width < name_width + 15)
 842                 name_width = width - 15;
 843
 844         /* Find the longest filename and max number of changes */
 845         reset = diff_get_color_opt(options, DIFF_RESET);
 846         set   = diff_get_color_opt(options, DIFF_PLAIN);
 847         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
 848         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
 849
 850         for (i = 0; i < data->nr; i++) {
 851                 struct diffstat_file *file = data->files[i];
 852                 int change = file->added + file->deleted;
 853                 fill_print_name(file);
 854                 len = strlen(file->print_name);
 855                 if (max_len < len)
 856                         max_len = len;
 857
 858                 if (file->is_binary || file->is_unmerged)
 859                         continue;
 860                 if (max_change < change)
 861                         max_change = change;
 862         }
 863
 864         /* Compute the width of the graph part;
 865          * 10 is for one blank at the beginning of the line plus
 866          * " | count " between the name and the graph.
 867          *
 868          * From here on, name_width is the width of the name area,
 869          * and width is the width of the graph area.
 870          */
 871         name_width = (name_width < max_len) ? name_width : max_len;
 872         if (width < (name_width + 10) + max_change)
 873                 width = width - (name_width + 10);
 874         else
 875                 width = max_change;
 876
 877         for (i = 0; i < data->nr; i++) {
 878                 const char *prefix = "";
 879                 char *name = data->files[i]->print_name;
 880                 int added = data->files[i]->added;
 881                 int deleted = data->files[i]->deleted;
 882                 int name_len;
 883
 884                 /*
 885                  * "scale" the filename
 886                  */
 887                 len = name_width;
 888                 name_len = strlen(name);
 889                 if (name_width < name_len) {
 890                         char *slash;
 891                         prefix = "...";
 892                         len -= 3;
 893                         name += name_len - len;
 894                         slash = strchr(name, '/');
 895                         if (slash)
 896                                 name = slash;
 897                 }
 898
 899                 if (data->files[i]->is_binary) {
 900                         show_name(options->file, prefix, name, len, reset, set);
 901                         fprintf(options->file, "  Bin ");
 902                         fprintf(options->file, "%s%d%s", del_c, deleted, reset);
 903                         fprintf(options->file, " -> ");
 904                         fprintf(options->file, "%s%d%s", add_c, added, reset);
 905                         fprintf(options->file, " bytes");
 906                         fprintf(options->file, "\n");
 907                         continue;
 908                 }
 909                 else if (data->files[i]->is_unmerged) {
 910                         show_name(options->file, prefix, name, len, reset, set);
 911                         fprintf(options->file, "  Unmerged\n");
 912                         continue;
 913                 }
 914                 else if (!data->files[i]->is_renamed &&
 915                          (added + deleted == 0)) {
 916                         total_files--;
 917                         continue;
 918                 }
 919
 920                 /*
 921                  * scale the add/delete
 922                  */
 923                 add = added;
 924                 del = deleted;
 925                 total = add + del;
 926                 adds += add;
 927                 dels += del;
 928
 929                 if (width <= max_change) {
 930                         add = scale_linear(add, width, max_change);
 931                         del = scale_linear(del, width, max_change);
 932                         total = add + del;
 933                 }
 934                 show_name(options->file, prefix, name, len, reset, set);
 935                 fprintf(options->file, "%5d%s", added + deleted,
 936                                 added + deleted ? " " : "");
 937                 show_graph(options->file, '+', add, add_c, reset);
 938                 show_graph(options->file, '-', del, del_c, reset);
 939                 fprintf(options->file, "\n");
 940         }
 941         fprintf(options->file,
 942                "%s %d files changed, %d insertions(+), %d deletions(-)%s\n",
 943                set, total_files, adds, dels, reset);
 944 }
 945
 946 static void show_shortstats(struct diffstat_t* data, struct diff_options *options)
 947 {
 948         int i, adds = 0, dels = 0, total_files = data->nr;
 949
 950         if (data->nr == 0)
 951                 return;
 952
 953         for (i = 0; i < data->nr; i++) {
 954                 if (!data->files[i]->is_binary &&
 955                     !data->files[i]->is_unmerged) {
 956                         int added = data->files[i]->added;
 957                         int deleted= data->files[i]->deleted;
 958                         if (!data->files[i]->is_renamed &&
 959                             (added + deleted == 0)) {
 960                                 total_files--;
 961                         } else {
 962                                 adds += added;
 963                                 dels += deleted;
 964                         }
 965                 }
 966         }
 967         fprintf(options->file, " %d files changed, %d insertions(+), %d deletions(-)\n",
 968                total_files, adds, dels);
 969 }
 970
 971 static void show_numstat(struct diffstat_t* data, struct diff_options *options)
 972 {
 973         int i;
 974
 975         if (data->nr == 0)
 976                 return;
 977
 978         for (i = 0; i < data->nr; i++) {
 979                 struct diffstat_file *file = data->files[i];
 980
 981                 if (file->is_binary)
 982                         fprintf(options->file, "-\t-\t");
 983                 else
 984                         fprintf(options->file,
 985                                 "%d\t%d\t", file->added, file->deleted);
 986                 if (options->line_termination) {
 987                         fill_print_name(file);
 988                         if (!file->is_renamed)
 989                                 write_name_quoted(file->name, options->file,
 990                                                   options->line_termination);
 991                         else {
 992                                 fputs(file->print_name, options->file);
 993                                 putc(options->line_termination, options->file);
 994                         }
 995                 } else {
 996                         if (file->is_renamed) {
 997                                 putc('\0', options->file);
 998                                 write_name_quoted(file->from_name, options->file, '\0');
 999                         }
1000                         write_name_quoted(file->name, options->file, '\0');
1001                 }
1002         }
1003 }
1004
1005 struct dirstat_file {
1006         const char *name;
1007         unsigned long changed;
1008 };
1009
1010 struct dirstat_dir {
1011         struct dirstat_file *files;
1012         int alloc, nr, percent, cumulative;
1013 };
1014
1015 static long gather_dirstat(FILE *file, struct dirstat_dir *dir, unsigned long changed, const char *base, int baselen)
1016 {
1017         unsigned long this_dir = 0;
1018         unsigned int sources = 0;
1019
1020         while (dir->nr) {
1021                 struct dirstat_file *f = dir->files;
1022                 int namelen = strlen(f->name);
1023                 unsigned long this;
1024                 char *slash;
1025
1026                 if (namelen < baselen)
1027                         break;
1028                 if (memcmp(f->name, base, baselen))
1029                         break;
1030                 slash = strchr(f->name + baselen, '/');
1031                 if (slash) {
1032                         int newbaselen = slash + 1 - f->name;
1033                         this = gather_dirstat(file, dir, changed, f->name, newbaselen);
1034                         sources++;
1035                 } else {
1036                         this = f->changed;
1037                         dir->files++;
1038                         dir->nr--;
1039                         sources += 2;
1040                 }
1041                 this_dir += this;
1042         }
1043
1044         /*
1045          * We don't report dirstat's for
1046          *  - the top level
1047          *  - or cases where everything came from a single directory
1048          *    under this directory (sources == 1).
1049          */
1050         if (baselen && sources != 1) {
1051                 int permille = this_dir * 1000 / changed;
1052                 if (permille) {
1053                         int percent = permille / 10;
1054                         if (percent >= dir->percent) {
1055                                 fprintf(file, "%4d.%01d%% %.*s\n", percent, permille % 10, baselen, base);
1056                                 if (!dir->cumulative)
1057                                         return 0;
1058                         }
1059                 }
1060         }
1061         return this_dir;
1062 }
1063
1064 static int dirstat_compare(const void *_a, const void *_b)
1065 {
1066         const struct dirstat_file *a = _a;
1067         const struct dirstat_file *b = _b;
1068         return strcmp(a->name, b->name);
1069 }
1070
1071 static void show_dirstat(struct diff_options *options)
1072 {
1073         int i;
1074         unsigned long changed;
1075         struct dirstat_dir dir;
1076         struct diff_queue_struct *q = &diff_queued_diff;
1077
1078         dir.files = NULL;
1079         dir.alloc = 0;
1080         dir.nr = 0;
1081         dir.percent = options->dirstat_percent;
1082         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1083
1084         changed = 0;
1085         for (i = 0; i < q->nr; i++) {
1086                 struct diff_filepair *p = q->queue[i];
1087                 const char *name;
1088                 unsigned long copied, added, damage;
1089
1090                 name = p->one->path ? p->one->path : p->two->path;
1091
1092                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1093                         diff_populate_filespec(p->one, 0);
1094                         diff_populate_filespec(p->two, 0);
1095                         diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1096                                                &copied, &added);
1097                         diff_free_filespec_data(p->one);
1098                         diff_free_filespec_data(p->two);
1099                 } else if (DIFF_FILE_VALID(p->one)) {
1100                         diff_populate_filespec(p->one, 1);
1101                         copied = added = 0;
1102                         diff_free_filespec_data(p->one);
1103                 } else if (DIFF_FILE_VALID(p->two)) {
1104                         diff_populate_filespec(p->two, 1);
1105                         copied = 0;
1106                         added = p->two->size;
1107                         diff_free_filespec_data(p->two);
1108                 } else
1109                         continue;
1110
1111                 /*
1112                  * Original minus copied is the removed material,
1113                  * added is the new material.  They are both damages
1114                  * made to the preimage.
1115                  */
1116                 damage = (p->one->size - copied) + added;
1117
1118                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1119                 dir.files[dir.nr].name = name;
1120                 dir.files[dir.nr].changed = damage;
1121                 changed += damage;
1122                 dir.nr++;
1123         }
1124
1125         /* This can happen even with many files, if everything was renames */
1126         if (!changed)
1127                 return;
1128
1129         /* Show all directories with more than x% of the changes */
1130         qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1131         gather_dirstat(options->file, &dir, changed, "", 0);
1132 }
1133
1134 static void free_diffstat_info(struct diffstat_t *diffstat)
1135 {
1136         int i;
1137         for (i = 0; i < diffstat->nr; i++) {
1138                 struct diffstat_file *f = diffstat->files[i];
1139                 if (f->name != f->print_name)
1140                         free(f->print_name);
1141                 free(f->name);
1142                 free(f->from_name);
1143                 free(f);
1144         }
1145         free(diffstat->files);
1146 }
1147
1148 struct checkdiff_t {
1149         struct xdiff_emit_state xm;
1150         const char *filename;
1151         int lineno;
1152         struct diff_options *o;
1153         unsigned ws_rule;
1154         unsigned status;
1155         int trailing_blanks_start;
1156 };
1157
1158 static int is_conflict_marker(const char *line, unsigned long len)
1159 {
1160         char firstchar;
1161         int cnt;
1162
1163         if (len < 8)
1164                 return 0;
1165         firstchar = line[0];
1166         switch (firstchar) {
1167         case '=': case '>': case '<':
1168                 break;
1169         default:
1170                 return 0;
1171         }
1172         for (cnt = 1; cnt < 7; cnt++)
1173                 if (line[cnt] != firstchar)
1174                         return 0;
1175         /* line[0] thru line[6] are same as firstchar */
1176         if (firstchar == '=') {
1177                 /* divider between ours and theirs? */
1178                 if (len != 8 || line[7] != '\n')
1179                         return 0;
1180         } else if (len < 8 || !isspace(line[7])) {
1181                 /* not divider before ours nor after theirs */
1182                 return 0;
1183         }
1184         return 1;
1185 }
1186
1187 static void checkdiff_consume(void *priv, char *line, unsigned long len)
1188 {
1189         struct checkdiff_t *data = priv;
1190         int color_diff = DIFF_OPT_TST(data->o, COLOR_DIFF);
1191         const char *ws = diff_get_color(color_diff, DIFF_WHITESPACE);
1192         const char *reset = diff_get_color(color_diff, DIFF_RESET);
1193         const char *set = diff_get_color(color_diff, DIFF_FILE_NEW);
1194         char *err;
1195
1196         if (line[0] == '+') {
1197                 unsigned bad;
1198                 data->lineno++;
1199                 if (!ws_blank_line(line + 1, len - 1, data->ws_rule))
1200                         data->trailing_blanks_start = 0;
1201                 else if (!data->trailing_blanks_start)
1202                         data->trailing_blanks_start = data->lineno;
1203                 if (is_conflict_marker(line + 1, len - 1)) {
1204                         data->status |= 1;
1205                         fprintf(data->o->file,
1206                                 "%s:%d: leftover conflict marker\n",
1207                                 data->filename, data->lineno);
1208                 }
1209                 bad = ws_check(line + 1, len - 1, data->ws_rule);
1210                 if (!bad)
1211                         return;
1212                 data->status |= bad;
1213                 err = whitespace_error_string(bad);
1214                 fprintf(data->o->file, "%s:%d: %s.\n",
1215                         data->filename, data->lineno, err);
1216                 free(err);
1217                 emit_line(data->o->file, set, reset, line, 1);
1218                 ws_check_emit(line + 1, len - 1, data->ws_rule,
1219                               data->o->file, set, reset, ws);
1220         } else if (line[0] == ' ') {
1221                 data->lineno++;
1222                 data->trailing_blanks_start = 0;
1223         } else if (line[0] == '@') {
1224                 char *plus = strchr(line, '+');
1225                 if (plus)
1226                         data->lineno = strtol(plus, NULL, 10) - 1;
1227                 else
1228                         die("invalid diff");
1229                 data->trailing_blanks_start = 0;
1230         }
1231 }
1232
1233 static unsigned char *deflate_it(char *data,
1234                                  unsigned long size,
1235                                  unsigned long *result_size)
1236 {
1237         int bound;
1238         unsigned char *deflated;
1239         z_stream stream;
1240
1241         memset(&stream, 0, sizeof(stream));
1242         deflateInit(&stream, zlib_compression_level);
1243         bound = deflateBound(&stream, size);
1244         deflated = xmalloc(bound);
1245         stream.next_out = deflated;
1246         stream.avail_out = bound;
1247
1248         stream.next_in = (unsigned char *)data;
1249         stream.avail_in = size;
1250         while (deflate(&stream, Z_FINISH) == Z_OK)
1251                 ; /* nothing */
1252         deflateEnd(&stream);
1253         *result_size = stream.total_out;
1254         return deflated;
1255 }
1256
1257 static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two)
1258 {
1259         void *cp;
1260         void *delta;
1261         void *deflated;
1262         void *data;
1263         unsigned long orig_size;
1264         unsigned long delta_size;
1265         unsigned long deflate_size;
1266         unsigned long data_size;
1267
1268         /* We could do deflated delta, or we could do just deflated two,
1269          * whichever is smaller.
1270          */
1271         delta = NULL;
1272         deflated = deflate_it(two->ptr, two->size, &deflate_size);
1273         if (one->size && two->size) {
1274                 delta = diff_delta(one->ptr, one->size,
1275                                    two->ptr, two->size,
1276                                    &delta_size, deflate_size);
1277                 if (delta) {
1278                         void *to_free = delta;
1279                         orig_size = delta_size;
1280                         delta = deflate_it(delta, delta_size, &delta_size);
1281                         free(to_free);
1282                 }
1283         }
1284
1285         if (delta && delta_size < deflate_size) {
1286                 fprintf(file, "delta %lu\n", orig_size);
1287                 free(deflated);
1288                 data = delta;
1289                 data_size = delta_size;
1290         }
1291         else {
1292                 fprintf(file, "literal %lu\n", two->size);
1293                 free(delta);
1294                 data = deflated;
1295                 data_size = deflate_size;
1296         }
1297
1298         /* emit data encoded in base85 */
1299         cp = data;
1300         while (data_size) {
1301                 int bytes = (52 < data_size) ? 52 : data_size;
1302                 char line[70];
1303                 data_size -= bytes;
1304                 if (bytes <= 26)
1305                         line[0] = bytes + 'A' - 1;
1306                 else
1307                         line[0] = bytes - 26 + 'a' - 1;
1308                 encode_85(line + 1, cp, bytes);
1309                 cp = (char *) cp + bytes;
1310                 fputs(line, file);
1311                 fputc('\n', file);
1312         }
1313         fprintf(file, "\n");
1314         free(data);
1315 }
1316
1317 static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two)
1318 {
1319         fprintf(file, "GIT binary patch\n");
1320         emit_binary_diff_body(file, one, two);
1321         emit_binary_diff_body(file, two, one);
1322 }
1323
1324 static void setup_diff_attr_check(struct git_attr_check *check)
1325 {
1326         static struct git_attr *attr_diff;
1327
1328         if (!attr_diff) {
1329                 attr_diff = git_attr("diff", 4);
1330         }
1331         check[0].attr = attr_diff;
1332 }
1333
1334 static void diff_filespec_check_attr(struct diff_filespec *one)
1335 {
1336         struct git_attr_check attr_diff_check;
1337         int check_from_data = 0;
1338
1339         if (one->checked_attr)
1340                 return;
1341
1342         setup_diff_attr_check(&attr_diff_check);
1343         one->is_binary = 0;
1344         one->funcname_pattern_ident = NULL;
1345
1346         if (!git_checkattr(one->path, 1, &attr_diff_check)) {
1347                 const char *value;
1348
1349                 /* binaryness */
1350                 value = attr_diff_check.value;
1351                 if (ATTR_TRUE(value))
1352                         ;
1353                 else if (ATTR_FALSE(value))
1354                         one->is_binary = 1;
1355                 else
1356                         check_from_data = 1;
1357
1358                 /* funcname pattern ident */
1359                 if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
1360                         ;
1361                 else
1362                         one->funcname_pattern_ident = value;
1363         }
1364
1365         if (check_from_data) {
1366                 if (!one->data && DIFF_FILE_VALID(one))
1367                         diff_populate_filespec(one, 0);
1368
1369                 if (one->data)
1370                         one->is_binary = buffer_is_binary(one->data, one->size);
1371         }
1372 }
1373
1374 int diff_filespec_is_binary(struct diff_filespec *one)
1375 {
1376         diff_filespec_check_attr(one);
1377         return one->is_binary;
1378 }
1379
1380 static const char *funcname_pattern(const char *ident)
1381 {
1382         struct funcname_pattern *pp;
1383
1384         for (pp = funcname_pattern_list; pp; pp = pp->next)
1385                 if (!strcmp(ident, pp->name))
1386                         return pp->pattern;
1387         return NULL;
1388 }
1389
1390 static struct builtin_funcname_pattern {
1391         const char *name;
1392         const char *pattern;
1393 } builtin_funcname_pattern[] = {
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\\).*\\)$"
1404                         },
1405         { "bibtex", "\\(@[a-zA-Z]\\{1,\\}[ \t]*{\\{0,1\\}[ \t]*[^ \t\"@',\\#}{~%]*\\).*$" },
1406         { "tex", "^\\(\\\\\\(\\(sub\\)*section\\|chapter\\|part\\)\\*\\{0,1\\}{.*\\)$" },
1407         { "ruby", "^\\s*\\(\\(class\\|module\\|def\\)\\s.*\\)$" },
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                 ecb.outf = xdiff_outf;
1540                 ecb.priv = &ecbdata;
1541                 ecbdata.xm.consume = fn_out_consume;
1542                 if (DIFF_OPT_TST(o, COLOR_DIFF_WORDS)) {
1543                         ecbdata.diff_words =
1544                                 xcalloc(1, sizeof(struct diff_words_data));
1545                         ecbdata.diff_words->file = o->file;
1546                 }
1547                 xdi_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
1548                 if (DIFF_OPT_TST(o, COLOR_DIFF_WORDS))
1549                         free_diff_words_data(&ecbdata);
1550         }
1551
1552  free_ab_and_return:
1553         diff_free_filespec_data(one);
1554         diff_free_filespec_data(two);
1555         free(a_one);
1556         free(b_two);
1557         return;
1558 }
1559
1560 static void builtin_diffstat(const char *name_a, const char *name_b,
1561                              struct diff_filespec *one,
1562                              struct diff_filespec *two,
1563                              struct diffstat_t *diffstat,
1564                              struct diff_options *o,
1565                              int complete_rewrite)
1566 {
1567         mmfile_t mf1, mf2;
1568         struct diffstat_file *data;
1569
1570         data = diffstat_add(diffstat, name_a, name_b);
1571
1572         if (!one || !two) {
1573                 data->is_unmerged = 1;
1574                 return;
1575         }
1576         if (complete_rewrite) {
1577                 diff_populate_filespec(one, 0);
1578                 diff_populate_filespec(two, 0);
1579                 data->deleted = count_lines(one->data, one->size);
1580                 data->added = count_lines(two->data, two->size);
1581                 goto free_and_return;
1582         }
1583         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1584                 die("unable to read files to diff");
1585
1586         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
1587                 data->is_binary = 1;
1588                 data->added = mf2.size;
1589                 data->deleted = mf1.size;
1590         } else {
1591                 /* Crazy xdl interfaces.. */
1592                 xpparam_t xpp;
1593                 xdemitconf_t xecfg;
1594                 xdemitcb_t ecb;
1595
1596                 memset(&xecfg, 0, sizeof(xecfg));
1597                 xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
1598                 ecb.outf = xdiff_outf;
1599                 ecb.priv = diffstat;
1600                 xdi_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
1601         }
1602
1603  free_and_return:
1604         diff_free_filespec_data(one);
1605         diff_free_filespec_data(two);
1606 }
1607
1608 static void builtin_checkdiff(const char *name_a, const char *name_b,
1609                               const char *attr_path,
1610                               struct diff_filespec *one,
1611                               struct diff_filespec *two,
1612                               struct diff_options *o)
1613 {
1614         mmfile_t mf1, mf2;
1615         struct checkdiff_t data;
1616
1617         if (!two)
1618                 return;
1619
1620         memset(&data, 0, sizeof(data));
1621         data.xm.consume = checkdiff_consume;
1622         data.filename = name_b ? name_b : name_a;
1623         data.lineno = 0;
1624         data.o = o;
1625         data.ws_rule = whitespace_rule(attr_path);
1626
1627         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1628                 die("unable to read files to diff");
1629
1630         /*
1631          * All the other codepaths check both sides, but not checking
1632          * the "old" side here is deliberate.  We are checking the newly
1633          * introduced changes, and as long as the "new" side is text, we
1634          * can and should check what it introduces.
1635          */
1636         if (diff_filespec_is_binary(two))
1637                 goto free_and_return;
1638         else {
1639                 /* Crazy xdl interfaces.. */
1640                 xpparam_t xpp;
1641                 xdemitconf_t xecfg;
1642                 xdemitcb_t ecb;
1643
1644                 memset(&xecfg, 0, sizeof(xecfg));
1645                 xecfg.ctxlen = 1; /* at least one context line */
1646                 xpp.flags = XDF_NEED_MINIMAL;
1647                 ecb.outf = xdiff_outf;
1648                 ecb.priv = &data;
1649                 xdi_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
1650
1651                 if ((data.ws_rule & WS_TRAILING_SPACE) &&
1652                     data.trailing_blanks_start) {
1653                         fprintf(o->file, "%s:%d: ends with blank lines.\n",
1654                                 data.filename, data.trailing_blanks_start);
1655                         data.status = 1; /* report errors */
1656                 }
1657         }
1658  free_and_return:
1659         diff_free_filespec_data(one);
1660         diff_free_filespec_data(two);
1661         if (data.status)
1662                 DIFF_OPT_SET(o, CHECK_FAILED);
1663 }
1664
1665 struct diff_filespec *alloc_filespec(const char *path)
1666 {
1667         int namelen = strlen(path);
1668         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
1669
1670         memset(spec, 0, sizeof(*spec));
1671         spec->path = (char *)(spec + 1);
1672         memcpy(spec->path, path, namelen+1);
1673         spec->count = 1;
1674         return spec;
1675 }
1676
1677 void free_filespec(struct diff_filespec *spec)
1678 {
1679         if (!--spec->count) {
1680                 diff_free_filespec_data(spec);
1681                 free(spec);
1682         }
1683 }
1684
1685 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
1686                    unsigned short mode)
1687 {
1688         if (mode) {
1689                 spec->mode = canon_mode(mode);
1690                 hashcpy(spec->sha1, sha1);
1691                 spec->sha1_valid = !is_null_sha1(sha1);
1692         }
1693 }
1694
1695 /*
1696  * Given a name and sha1 pair, if the index tells us the file in
1697  * the work tree has that object contents, return true, so that
1698  * prepare_temp_file() does not have to inflate and extract.
1699  */
1700 static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
1701 {
1702         struct cache_entry *ce;
1703         struct stat st;
1704         int pos, len;
1705
1706         /* We do not read the cache ourselves here, because the
1707          * benchmark with my previous version that always reads cache
1708          * shows that it makes things worse for diff-tree comparing
1709          * two linux-2.6 kernel trees in an already checked out work
1710          * tree.  This is because most diff-tree comparisons deal with
1711          * only a small number of files, while reading the cache is
1712          * expensive for a large project, and its cost outweighs the
1713          * savings we get by not inflating the object to a temporary
1714          * file.  Practically, this code only helps when we are used
1715          * by diff-cache --cached, which does read the cache before
1716          * calling us.
1717          */
1718         if (!active_cache)
1719                 return 0;
1720
1721         /* We want to avoid the working directory if our caller
1722          * doesn't need the data in a normal file, this system
1723          * is rather slow with its stat/open/mmap/close syscalls,
1724          * and the object is contained in a pack file.  The pack
1725          * is probably already open and will be faster to obtain
1726          * the data through than the working directory.  Loose
1727          * objects however would tend to be slower as they need
1728          * to be individually opened and inflated.
1729          */
1730         if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1, NULL))
1731                 return 0;
1732
1733         len = strlen(name);
1734         pos = cache_name_pos(name, len);
1735         if (pos < 0)
1736                 return 0;
1737         ce = active_cache[pos];
1738
1739         /*
1740          * This is not the sha1 we are looking for, or
1741          * unreusable because it is not a regular file.
1742          */
1743         if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
1744                 return 0;
1745
1746         /*
1747          * If ce matches the file in the work tree, we can reuse it.
1748          */
1749         if (ce_uptodate(ce) ||
1750             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
1751                 return 1;
1752
1753         return 0;
1754 }
1755
1756 static int populate_from_stdin(struct diff_filespec *s)
1757 {
1758         struct strbuf buf;
1759         size_t size = 0;
1760
1761         strbuf_init(&buf, 0);
1762         if (strbuf_read(&buf, 0, 0) < 0)
1763                 return error("error while reading from stdin %s",
1764                                      strerror(errno));
1765
1766         s->should_munmap = 0;
1767         s->data = strbuf_detach(&buf, &size);
1768         s->size = size;
1769         s->should_free = 1;
1770         return 0;
1771 }
1772
1773 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
1774 {
1775         int len;
1776         char *data = xmalloc(100);
1777         len = snprintf(data, 100,
1778                 "Subproject commit %s\n", sha1_to_hex(s->sha1));
1779         s->data = data;
1780         s->size = len;
1781         s->should_free = 1;
1782         if (size_only) {
1783                 s->data = NULL;
1784                 free(data);
1785         }
1786         return 0;
1787 }
1788
1789 /*
1790  * While doing rename detection and pickaxe operation, we may need to
1791  * grab the data for the blob (or file) for our own in-core comparison.
1792  * diff_filespec has data and size fields for this purpose.
1793  */
1794 int diff_populate_filespec(struct diff_filespec *s, int size_only)
1795 {
1796         int err = 0;
1797         if (!DIFF_FILE_VALID(s))
1798                 die("internal error: asking to populate invalid file.");
1799         if (S_ISDIR(s->mode))
1800                 return -1;
1801
1802         if (s->data)
1803                 return 0;
1804
1805         if (size_only && 0 < s->size)
1806                 return 0;
1807
1808         if (S_ISGITLINK(s->mode))
1809                 return diff_populate_gitlink(s, size_only);
1810
1811         if (!s->sha1_valid ||
1812             reuse_worktree_file(s->path, s->sha1, 0)) {
1813                 struct strbuf buf;
1814                 struct stat st;
1815                 int fd;
1816
1817                 if (!strcmp(s->path, "-"))
1818                         return populate_from_stdin(s);
1819
1820                 if (lstat(s->path, &st) < 0) {
1821                         if (errno == ENOENT) {
1822                         err_empty:
1823                                 err = -1;
1824                         empty:
1825                                 s->data = (char *)"";
1826                                 s->size = 0;
1827                                 return err;
1828                         }
1829                 }
1830                 s->size = xsize_t(st.st_size);
1831                 if (!s->size)
1832                         goto empty;
1833                 if (size_only)
1834                         return 0;
1835                 if (S_ISLNK(st.st_mode)) {
1836                         int ret;
1837                         s->data = xmalloc(s->size);
1838                         s->should_free = 1;
1839                         ret = readlink(s->path, s->data, s->size);
1840                         if (ret < 0) {
1841                                 free(s->data);
1842                                 goto err_empty;
1843                         }
1844                         return 0;
1845                 }
1846                 fd = open(s->path, O_RDONLY);
1847                 if (fd < 0)
1848                         goto err_empty;
1849                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
1850                 close(fd);
1851                 s->should_munmap = 1;
1852
1853                 /*
1854                  * Convert from working tree format to canonical git format
1855                  */
1856                 strbuf_init(&buf, 0);
1857                 if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
1858                         size_t size = 0;
1859                         munmap(s->data, s->size);
1860                         s->should_munmap = 0;
1861                         s->data = strbuf_detach(&buf, &size);
1862                         s->size = size;
1863                         s->should_free = 1;
1864                 }
1865         }
1866         else {
1867                 enum object_type type;
1868                 if (size_only)
1869                         type = sha1_object_info(s->sha1, &s->size);
1870                 else {
1871                         s->data = read_sha1_file(s->sha1, &type, &s->size);
1872                         s->should_free = 1;
1873                 }
1874         }
1875         return 0;
1876 }
1877
1878 void diff_free_filespec_blob(struct diff_filespec *s)
1879 {
1880         if (s->should_free)
1881                 free(s->data);
1882         else if (s->should_munmap)
1883                 munmap(s->data, s->size);
1884
1885         if (s->should_free || s->should_munmap) {
1886                 s->should_free = s->should_munmap = 0;
1887                 s->data = NULL;
1888         }
1889 }
1890
1891 void diff_free_filespec_data(struct diff_filespec *s)
1892 {
1893         diff_free_filespec_blob(s);
1894         free(s->cnt_data);
1895         s->cnt_data = NULL;
1896 }
1897
1898 static void prep_temp_blob(struct diff_tempfile *temp,
1899                            void *blob,
1900                            unsigned long size,
1901                            const unsigned char *sha1,
1902                            int mode)
1903 {
1904         int fd;
1905
1906         fd = git_mkstemp(temp->tmp_path, PATH_MAX, ".diff_XXXXXX");
1907         if (fd < 0)
1908                 die("unable to create temp-file: %s", strerror(errno));
1909         if (write_in_full(fd, blob, size) != size)
1910                 die("unable to write temp-file");
1911         close(fd);
1912         temp->name = temp->tmp_path;
1913         strcpy(temp->hex, sha1_to_hex(sha1));
1914         temp->hex[40] = 0;
1915         sprintf(temp->mode, "%06o", mode);
1916 }
1917
1918 static void prepare_temp_file(const char *name,
1919                               struct diff_tempfile *temp,
1920                               struct diff_filespec *one)
1921 {
1922         if (!DIFF_FILE_VALID(one)) {
1923         not_a_valid_file:
1924                 /* A '-' entry produces this for file-2, and
1925                  * a '+' entry produces this for file-1.
1926                  */
1927                 temp->name = "/dev/null";
1928                 strcpy(temp->hex, ".");
1929                 strcpy(temp->mode, ".");
1930                 return;
1931         }
1932
1933         if (!one->sha1_valid ||
1934             reuse_worktree_file(name, one->sha1, 1)) {
1935                 struct stat st;
1936                 if (lstat(name, &st) < 0) {
1937                         if (errno == ENOENT)
1938                                 goto not_a_valid_file;
1939                         die("stat(%s): %s", name, strerror(errno));
1940                 }
1941                 if (S_ISLNK(st.st_mode)) {
1942                         int ret;
1943                         char buf[PATH_MAX + 1]; /* ought to be SYMLINK_MAX */
1944                         size_t sz = xsize_t(st.st_size);
1945                         if (sizeof(buf) <= st.st_size)
1946                                 die("symlink too long: %s", name);
1947                         ret = readlink(name, buf, sz);
1948                         if (ret < 0)
1949                                 die("readlink(%s)", name);
1950                         prep_temp_blob(temp, buf, sz,
1951                                        (one->sha1_valid ?
1952                                         one->sha1 : null_sha1),
1953                                        (one->sha1_valid ?
1954                                         one->mode : S_IFLNK));
1955                 }
1956                 else {
1957                         /* we can borrow from the file in the work tree */
1958                         temp->name = name;
1959                         if (!one->sha1_valid)
1960                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
1961                         else
1962                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
1963                         /* Even though we may sometimes borrow the
1964                          * contents from the work tree, we always want
1965                          * one->mode.  mode is trustworthy even when
1966                          * !(one->sha1_valid), as long as
1967                          * DIFF_FILE_VALID(one).
1968                          */
1969                         sprintf(temp->mode, "%06o", one->mode);
1970                 }
1971                 return;
1972         }
1973         else {
1974                 if (diff_populate_filespec(one, 0))
1975                         die("cannot read data blob for %s", one->path);
1976                 prep_temp_blob(temp, one->data, one->size,
1977                                one->sha1, one->mode);
1978         }
1979 }
1980
1981 static void remove_tempfile(void)
1982 {
1983         int i;
1984
1985         for (i = 0; i < 2; i++)
1986                 if (diff_temp[i].name == diff_temp[i].tmp_path) {
1987                         unlink(diff_temp[i].name);
1988                         diff_temp[i].name = NULL;
1989                 }
1990 }
1991
1992 static void remove_tempfile_on_signal(int signo)
1993 {
1994         remove_tempfile();
1995         signal(SIGINT, SIG_DFL);
1996         raise(signo);
1997 }
1998
1999 /* An external diff command takes:
2000  *
2001  * diff-cmd name infile1 infile1-sha1 infile1-mode \
2002  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2003  *
2004  */
2005 static void run_external_diff(const char *pgm,
2006                               const char *name,
2007                               const char *other,
2008                               struct diff_filespec *one,
2009                               struct diff_filespec *two,
2010                               const char *xfrm_msg,
2011                               int complete_rewrite)
2012 {
2013         const char *spawn_arg[10];
2014         struct diff_tempfile *temp = diff_temp;
2015         int retval;
2016         static int atexit_asked = 0;
2017         const char *othername;
2018         const char **arg = &spawn_arg[0];
2019
2020         othername = (other? other : name);
2021         if (one && two) {
2022                 prepare_temp_file(name, &temp[0], one);
2023                 prepare_temp_file(othername, &temp[1], two);
2024                 if (! atexit_asked &&
2025                     (temp[0].name == temp[0].tmp_path ||
2026                      temp[1].name == temp[1].tmp_path)) {
2027                         atexit_asked = 1;
2028                         atexit(remove_tempfile);
2029                 }
2030                 signal(SIGINT, remove_tempfile_on_signal);
2031         }
2032
2033         if (one && two) {
2034                 *arg++ = pgm;
2035                 *arg++ = name;
2036                 *arg++ = temp[0].name;
2037                 *arg++ = temp[0].hex;
2038                 *arg++ = temp[0].mode;
2039                 *arg++ = temp[1].name;
2040                 *arg++ = temp[1].hex;
2041                 *arg++ = temp[1].mode;
2042                 if (other) {
2043                         *arg++ = other;
2044                         *arg++ = xfrm_msg;
2045                 }
2046         } else {
2047                 *arg++ = pgm;
2048                 *arg++ = name;
2049         }
2050         *arg = NULL;
2051         fflush(NULL);
2052         retval = run_command_v_opt(spawn_arg, 0);
2053         remove_tempfile();
2054         if (retval) {
2055                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
2056                 exit(1);
2057         }
2058 }
2059
2060 static const char *external_diff_attr(const char *name)
2061 {
2062         struct git_attr_check attr_diff_check;
2063
2064         if (!name)
2065                 return NULL;
2066
2067         setup_diff_attr_check(&attr_diff_check);
2068         if (!git_checkattr(name, 1, &attr_diff_check)) {
2069                 const char *value = attr_diff_check.value;
2070                 if (!ATTR_TRUE(value) &&
2071                     !ATTR_FALSE(value) &&
2072                     !ATTR_UNSET(value)) {
2073                         struct ll_diff_driver *drv;
2074
2075                         for (drv = user_diff; drv; drv = drv->next)
2076                                 if (!strcmp(drv->name, value))
2077                                         return drv->cmd;
2078                 }
2079         }
2080         return NULL;
2081 }
2082
2083 static void run_diff_cmd(const char *pgm,
2084                          const char *name,
2085                          const char *other,
2086                          const char *attr_path,
2087                          struct diff_filespec *one,
2088                          struct diff_filespec *two,
2089                          const char *xfrm_msg,
2090                          struct diff_options *o,
2091                          int complete_rewrite)
2092 {
2093         if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
2094                 pgm = NULL;
2095         else {
2096                 const char *cmd = external_diff_attr(attr_path);
2097                 if (cmd)
2098                         pgm = cmd;
2099         }
2100
2101         if (pgm) {
2102                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
2103                                   complete_rewrite);
2104                 return;
2105         }
2106         if (one && two)
2107                 builtin_diff(name, other ? other : name,
2108                              one, two, xfrm_msg, o, complete_rewrite);
2109         else
2110                 fprintf(o->file, "* Unmerged path %s\n", name);
2111 }
2112
2113 static void diff_fill_sha1_info(struct diff_filespec *one)
2114 {
2115         if (DIFF_FILE_VALID(one)) {
2116                 if (!one->sha1_valid) {
2117                         struct stat st;
2118                         if (!strcmp(one->path, "-")) {
2119                                 hashcpy(one->sha1, null_sha1);
2120                                 return;
2121                         }
2122                         if (lstat(one->path, &st) < 0)
2123                                 die("stat %s", one->path);
2124                         if (index_path(one->sha1, one->path, &st, 0))
2125                                 die("cannot hash %s\n", one->path);
2126                 }
2127         }
2128         else
2129                 hashclr(one->sha1);
2130 }
2131
2132 static int similarity_index(struct diff_filepair *p)
2133 {
2134         return p->score * 100 / MAX_SCORE;
2135 }
2136
2137 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
2138 {
2139         /* Strip the prefix but do not molest /dev/null and absolute paths */
2140         if (*namep && **namep != '/')
2141                 *namep += prefix_length;
2142         if (*otherp && **otherp != '/')
2143                 *otherp += prefix_length;
2144 }
2145
2146 static void run_diff(struct diff_filepair *p, struct diff_options *o)
2147 {
2148         const char *pgm = external_diff();
2149         struct strbuf msg;
2150         char *xfrm_msg;
2151         struct diff_filespec *one = p->one;
2152         struct diff_filespec *two = p->two;
2153         const char *name;
2154         const char *other;
2155         const char *attr_path;
2156         int complete_rewrite = 0;
2157
2158         name  = p->one->path;
2159         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2160         attr_path = name;
2161         if (o->prefix_length)
2162                 strip_prefix(o->prefix_length, &name, &other);
2163
2164         if (DIFF_PAIR_UNMERGED(p)) {
2165                 run_diff_cmd(pgm, name, NULL, attr_path,
2166                              NULL, NULL, NULL, o, 0);
2167                 return;
2168         }
2169
2170         diff_fill_sha1_info(one);
2171         diff_fill_sha1_info(two);
2172
2173         strbuf_init(&msg, PATH_MAX * 2 + 300);
2174         switch (p->status) {
2175         case DIFF_STATUS_COPIED:
2176                 strbuf_addf(&msg, "similarity index %d%%", similarity_index(p));
2177                 strbuf_addstr(&msg, "\ncopy from ");
2178                 quote_c_style(name, &msg, NULL, 0);
2179                 strbuf_addstr(&msg, "\ncopy to ");
2180                 quote_c_style(other, &msg, NULL, 0);
2181                 strbuf_addch(&msg, '\n');
2182                 break;
2183         case DIFF_STATUS_RENAMED:
2184                 strbuf_addf(&msg, "similarity index %d%%", similarity_index(p));
2185                 strbuf_addstr(&msg, "\nrename from ");
2186                 quote_c_style(name, &msg, NULL, 0);
2187                 strbuf_addstr(&msg, "\nrename to ");
2188                 quote_c_style(other, &msg, NULL, 0);
2189                 strbuf_addch(&msg, '\n');
2190                 break;
2191         case DIFF_STATUS_MODIFIED:
2192                 if (p->score) {
2193                         strbuf_addf(&msg, "dissimilarity index %d%%\n",
2194                                         similarity_index(p));
2195                         complete_rewrite = 1;
2196                         break;
2197                 }
2198                 /* fallthru */
2199         default:
2200                 /* nothing */
2201                 ;
2202         }
2203
2204         if (hashcmp(one->sha1, two->sha1)) {
2205                 int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
2206
2207                 if (DIFF_OPT_TST(o, BINARY)) {
2208                         mmfile_t mf;
2209                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
2210                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
2211                                 abbrev = 40;
2212                 }
2213                 strbuf_addf(&msg, "index %.*s..%.*s",
2214                                 abbrev, sha1_to_hex(one->sha1),
2215                                 abbrev, sha1_to_hex(two->sha1));
2216                 if (one->mode == two->mode)
2217                         strbuf_addf(&msg, " %06o", one->mode);
2218                 strbuf_addch(&msg, '\n');
2219         }
2220
2221         if (msg.len)
2222                 strbuf_setlen(&msg, msg.len - 1);
2223         xfrm_msg = msg.len ? msg.buf : NULL;
2224
2225         if (!pgm &&
2226             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
2227             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
2228                 /* a filepair that changes between file and symlink
2229                  * needs to be split into deletion and creation.
2230                  */
2231                 struct diff_filespec *null = alloc_filespec(two->path);
2232                 run_diff_cmd(NULL, name, other, attr_path,
2233                              one, null, xfrm_msg, o, 0);
2234                 free(null);
2235                 null = alloc_filespec(one->path);
2236                 run_diff_cmd(NULL, name, other, attr_path,
2237                              null, two, xfrm_msg, o, 0);
2238                 free(null);
2239         }
2240         else
2241                 run_diff_cmd(pgm, name, other, attr_path,
2242                              one, two, xfrm_msg, o, complete_rewrite);
2243
2244         strbuf_release(&msg);
2245 }
2246
2247 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
2248                          struct diffstat_t *diffstat)
2249 {
2250         const char *name;
2251         const char *other;
2252         int complete_rewrite = 0;
2253
2254         if (DIFF_PAIR_UNMERGED(p)) {
2255                 /* unmerged */
2256                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, 0);
2257                 return;
2258         }
2259
2260         name = p->one->path;
2261         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2262
2263         if (o->prefix_length)
2264                 strip_prefix(o->prefix_length, &name, &other);
2265
2266         diff_fill_sha1_info(p->one);
2267         diff_fill_sha1_info(p->two);
2268
2269         if (p->status == DIFF_STATUS_MODIFIED && p->score)
2270                 complete_rewrite = 1;
2271         builtin_diffstat(name, other, p->one, p->two, diffstat, o, complete_rewrite);
2272 }
2273
2274 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
2275 {
2276         const char *name;
2277         const char *other;
2278         const char *attr_path;
2279
2280         if (DIFF_PAIR_UNMERGED(p)) {
2281                 /* unmerged */
2282                 return;
2283         }
2284
2285         name = p->one->path;
2286         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2287         attr_path = other ? other : name;
2288
2289         if (o->prefix_length)
2290                 strip_prefix(o->prefix_length, &name, &other);
2291
2292         diff_fill_sha1_info(p->one);
2293         diff_fill_sha1_info(p->two);
2294
2295         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
2296 }
2297
2298 void diff_setup(struct diff_options *options)
2299 {
2300         memset(options, 0, sizeof(*options));
2301
2302         options->file = stdout;
2303
2304         options->line_termination = '\n';
2305         options->break_opt = -1;
2306         options->rename_limit = -1;
2307         options->dirstat_percent = 3;
2308         DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
2309         options->context = 3;
2310
2311         options->change = diff_change;
2312         options->add_remove = diff_addremove;
2313         if (diff_use_color_default > 0)
2314                 DIFF_OPT_SET(options, COLOR_DIFF);
2315         else
2316                 DIFF_OPT_CLR(options, COLOR_DIFF);
2317         options->detect_rename = diff_detect_rename_default;
2318
2319         options->a_prefix = "a/";
2320         options->b_prefix = "b/";
2321 }
2322
2323 int diff_setup_done(struct diff_options *options)
2324 {
2325         int count = 0;
2326
2327         if (options->output_format & DIFF_FORMAT_NAME)
2328                 count++;
2329         if (options->output_format & DIFF_FORMAT_NAME_STATUS)
2330                 count++;
2331         if (options->output_format & DIFF_FORMAT_CHECKDIFF)
2332                 count++;
2333         if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
2334                 count++;
2335         if (count > 1)
2336                 die("--name-only, --name-status, --check and -s are mutually exclusive");
2337
2338         if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
2339                 options->detect_rename = DIFF_DETECT_COPY;
2340
2341         if (!DIFF_OPT_TST(options, RELATIVE_NAME))
2342                 options->prefix = NULL;
2343         if (options->prefix)
2344                 options->prefix_length = strlen(options->prefix);
2345         else
2346                 options->prefix_length = 0;
2347
2348         if (options->output_format & (DIFF_FORMAT_NAME |
2349                                       DIFF_FORMAT_NAME_STATUS |
2350                                       DIFF_FORMAT_CHECKDIFF |
2351                                       DIFF_FORMAT_NO_OUTPUT))
2352                 options->output_format &= ~(DIFF_FORMAT_RAW |
2353                                             DIFF_FORMAT_NUMSTAT |
2354                                             DIFF_FORMAT_DIFFSTAT |
2355                                             DIFF_FORMAT_SHORTSTAT |
2356                                             DIFF_FORMAT_DIRSTAT |
2357                                             DIFF_FORMAT_SUMMARY |
2358                                             DIFF_FORMAT_PATCH);
2359
2360         /*
2361          * These cases always need recursive; we do not drop caller-supplied
2362          * recursive bits for other formats here.
2363          */
2364         if (options->output_format & (DIFF_FORMAT_PATCH |
2365                                       DIFF_FORMAT_NUMSTAT |
2366                                       DIFF_FORMAT_DIFFSTAT |
2367                                       DIFF_FORMAT_SHORTSTAT |
2368                                       DIFF_FORMAT_DIRSTAT |
2369                                       DIFF_FORMAT_SUMMARY |
2370                                       DIFF_FORMAT_CHECKDIFF))
2371                 DIFF_OPT_SET(options, RECURSIVE);
2372         /*
2373          * Also pickaxe would not work very well if you do not say recursive
2374          */
2375         if (options->pickaxe)
2376                 DIFF_OPT_SET(options, RECURSIVE);
2377
2378         if (options->detect_rename && options->rename_limit < 0)
2379                 options->rename_limit = diff_rename_limit_default;
2380         if (options->setup & DIFF_SETUP_USE_CACHE) {
2381                 if (!active_cache)
2382                         /* read-cache does not die even when it fails
2383                          * so it is safe for us to do this here.  Also
2384                          * it does not smudge active_cache or active_nr
2385                          * when it fails, so we do not have to worry about
2386                          * cleaning it up ourselves either.
2387                          */
2388                         read_cache();
2389         }
2390         if (options->abbrev <= 0 || 40 < options->abbrev)
2391                 options->abbrev = 40; /* full */
2392
2393         /*
2394          * It does not make sense to show the first hit we happened
2395          * to have found.  It does not make sense not to return with
2396          * exit code in such a case either.
2397          */
2398         if (DIFF_OPT_TST(options, QUIET)) {
2399                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
2400                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
2401         }
2402
2403         /*
2404          * If we postprocess in diffcore, we cannot simply return
2405          * upon the first hit.  We need to run diff as usual.
2406          */
2407         if (options->pickaxe || options->filter)
2408                 DIFF_OPT_CLR(options, QUIET);
2409
2410         return 0;
2411 }
2412
2413 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
2414 {
2415         char c, *eq;
2416         int len;
2417
2418         if (*arg != '-')
2419                 return 0;
2420         c = *++arg;
2421         if (!c)
2422                 return 0;
2423         if (c == arg_short) {
2424                 c = *++arg;
2425                 if (!c)
2426                         return 1;
2427                 if (val && isdigit(c)) {
2428                         char *end;
2429                         int n = strtoul(arg, &end, 10);
2430                         if (*end)
2431                                 return 0;
2432                         *val = n;
2433                         return 1;
2434                 }
2435                 return 0;
2436         }
2437         if (c != '-')
2438                 return 0;
2439         arg++;
2440         eq = strchr(arg, '=');
2441         if (eq)
2442                 len = eq - arg;
2443         else
2444                 len = strlen(arg);
2445         if (!len || strncmp(arg, arg_long, len))
2446                 return 0;
2447         if (eq) {
2448                 int n;
2449                 char *end;
2450                 if (!isdigit(*++eq))
2451                         return 0;
2452                 n = strtoul(eq, &end, 10);
2453                 if (*end)
2454                         return 0;
2455                 *val = n;
2456         }
2457         return 1;
2458 }
2459
2460 static int diff_scoreopt_parse(const char *opt);
2461
2462 int diff_opt_parse(struct diff_options *options, const char **av, int ac)
2463 {
2464         const char *arg = av[0];
2465
2466         /* Output format options */
2467         if (!strcmp(arg, "-p") || !strcmp(arg, "-u"))
2468                 options->output_format |= DIFF_FORMAT_PATCH;
2469         else if (opt_arg(arg, 'U', "unified", &options->context))
2470                 options->output_format |= DIFF_FORMAT_PATCH;
2471         else if (!strcmp(arg, "--raw"))
2472                 options->output_format |= DIFF_FORMAT_RAW;
2473         else if (!strcmp(arg, "--patch-with-raw"))
2474                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW;
2475         else if (!strcmp(arg, "--numstat"))
2476                 options->output_format |= DIFF_FORMAT_NUMSTAT;
2477         else if (!strcmp(arg, "--shortstat"))
2478                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
2479         else if (opt_arg(arg, 'X', "dirstat", &options->dirstat_percent))
2480                 options->output_format |= DIFF_FORMAT_DIRSTAT;
2481         else if (!strcmp(arg, "--cumulative")) {
2482                 options->output_format |= DIFF_FORMAT_DIRSTAT;
2483                 DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
2484         }
2485         else if (!strcmp(arg, "--check"))
2486                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
2487         else if (!strcmp(arg, "--summary"))
2488                 options->output_format |= DIFF_FORMAT_SUMMARY;
2489         else if (!strcmp(arg, "--patch-with-stat"))
2490                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT;
2491         else if (!strcmp(arg, "--name-only"))
2492                 options->output_format |= DIFF_FORMAT_NAME;
2493         else if (!strcmp(arg, "--name-status"))
2494                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
2495         else if (!strcmp(arg, "-s"))
2496                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
2497         else if (!prefixcmp(arg, "--stat")) {
2498                 char *end;
2499                 int width = options->stat_width;
2500                 int name_width = options->stat_name_width;
2501                 arg += 6;
2502                 end = (char *)arg;
2503
2504                 switch (*arg) {
2505                 case '-':
2506                         if (!prefixcmp(arg, "-width="))
2507                                 width = strtoul(arg + 7, &end, 10);
2508                         else if (!prefixcmp(arg, "-name-width="))
2509                                 name_width = strtoul(arg + 12, &end, 10);
2510                         break;
2511                 case '=':
2512                         width = strtoul(arg+1, &end, 10);
2513                         if (*end == ',')
2514                                 name_width = strtoul(end+1, &end, 10);
2515                 }
2516
2517                 /* Important! This checks all the error cases! */
2518                 if (*end)
2519                         return 0;
2520                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
2521                 options->stat_name_width = name_width;
2522                 options->stat_width = width;
2523         }
2524
2525         /* renames options */
2526         else if (!prefixcmp(arg, "-B")) {
2527                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
2528                         return -1;
2529         }
2530         else if (!prefixcmp(arg, "-M")) {
2531                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
2532                         return -1;
2533                 options->detect_rename = DIFF_DETECT_RENAME;
2534         }
2535         else if (!prefixcmp(arg, "-C")) {
2536                 if (options->detect_rename == DIFF_DETECT_COPY)
2537                         DIFF_OPT_SET(options, FIND_COPIES_HARDER);
2538                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
2539                         return -1;
2540                 options->detect_rename = DIFF_DETECT_COPY;
2541         }
2542         else if (!strcmp(arg, "--no-renames"))
2543                 options->detect_rename = 0;
2544         else if (!strcmp(arg, "--relative"))
2545                 DIFF_OPT_SET(options, RELATIVE_NAME);
2546         else if (!prefixcmp(arg, "--relative=")) {
2547                 DIFF_OPT_SET(options, RELATIVE_NAME);
2548                 options->prefix = arg + 11;
2549         }
2550
2551         /* xdiff options */
2552         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
2553                 options->xdl_opts |= XDF_IGNORE_WHITESPACE;
2554         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
2555                 options->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
2556         else if (!strcmp(arg, "--ignore-space-at-eol"))
2557                 options->xdl_opts |= XDF_IGNORE_WHITESPACE_AT_EOL;
2558
2559         /* flags options */
2560         else if (!strcmp(arg, "--binary")) {
2561                 options->output_format |= DIFF_FORMAT_PATCH;
2562                 DIFF_OPT_SET(options, BINARY);
2563         }
2564         else if (!strcmp(arg, "--full-index"))
2565                 DIFF_OPT_SET(options, FULL_INDEX);
2566         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
2567                 DIFF_OPT_SET(options, TEXT);
2568         else if (!strcmp(arg, "-R"))
2569                 DIFF_OPT_SET(options, REVERSE_DIFF);
2570         else if (!strcmp(arg, "--find-copies-harder"))
2571                 DIFF_OPT_SET(options, FIND_COPIES_HARDER);
2572         else if (!strcmp(arg, "--follow"))
2573                 DIFF_OPT_SET(options, FOLLOW_RENAMES);
2574         else if (!strcmp(arg, "--color"))
2575                 DIFF_OPT_SET(options, COLOR_DIFF);
2576         else if (!strcmp(arg, "--no-color"))
2577                 DIFF_OPT_CLR(options, COLOR_DIFF);
2578         else if (!strcmp(arg, "--color-words"))
2579                 options->flags |= DIFF_OPT_COLOR_DIFF | DIFF_OPT_COLOR_DIFF_WORDS;
2580         else if (!strcmp(arg, "--exit-code"))
2581                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
2582         else if (!strcmp(arg, "--quiet"))
2583                 DIFF_OPT_SET(options, QUIET);
2584         else if (!strcmp(arg, "--ext-diff"))
2585                 DIFF_OPT_SET(options, ALLOW_EXTERNAL);
2586         else if (!strcmp(arg, "--no-ext-diff"))
2587                 DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
2588         else if (!strcmp(arg, "--ignore-submodules"))
2589                 DIFF_OPT_SET(options, IGNORE_SUBMODULES);
2590
2591         /* misc options */
2592         else if (!strcmp(arg, "-z"))
2593                 options->line_termination = 0;
2594         else if (!prefixcmp(arg, "-l"))
2595                 options->rename_limit = strtoul(arg+2, NULL, 10);
2596         else if (!prefixcmp(arg, "-S"))
2597                 options->pickaxe = arg + 2;
2598         else if (!strcmp(arg, "--pickaxe-all"))
2599                 options->pickaxe_opts = DIFF_PICKAXE_ALL;
2600         else if (!strcmp(arg, "--pickaxe-regex"))
2601                 options->pickaxe_opts = DIFF_PICKAXE_REGEX;
2602         else if (!prefixcmp(arg, "-O"))
2603                 options->orderfile = arg + 2;
2604         else if (!prefixcmp(arg, "--diff-filter="))
2605                 options->filter = arg + 14;
2606         else if (!strcmp(arg, "--abbrev"))
2607                 options->abbrev = DEFAULT_ABBREV;
2608         else if (!prefixcmp(arg, "--abbrev=")) {
2609                 options->abbrev = strtoul(arg + 9, NULL, 10);
2610                 if (options->abbrev < MINIMUM_ABBREV)
2611                         options->abbrev = MINIMUM_ABBREV;
2612                 else if (40 < options->abbrev)
2613                         options->abbrev = 40;
2614         }
2615         else if (!prefixcmp(arg, "--src-prefix="))
2616                 options->a_prefix = arg + 13;
2617         else if (!prefixcmp(arg, "--dst-prefix="))
2618                 options->b_prefix = arg + 13;
2619         else if (!strcmp(arg, "--no-prefix"))
2620                 options->a_prefix = options->b_prefix = "";
2621         else if (!prefixcmp(arg, "--output=")) {
2622                 options->file = fopen(arg + strlen("--output="), "w");
2623                 options->close_file = 1;
2624         } else
2625                 return 0;
2626         return 1;
2627 }
2628
2629 static int parse_num(const char **cp_p)
2630 {
2631         unsigned long num, scale;
2632         int ch, dot;
2633         const char *cp = *cp_p;
2634
2635         num = 0;
2636         scale = 1;
2637         dot = 0;
2638         for(;;) {
2639                 ch = *cp;
2640                 if ( !dot && ch == '.' ) {
2641                         scale = 1;
2642                         dot = 1;
2643                 } else if ( ch == '%' ) {
2644                         scale = dot ? scale*100 : 100;
2645                         cp++;   /* % is always at the end */
2646                         break;
2647                 } else if ( ch >= '0' && ch <= '9' ) {
2648                         if ( scale < 100000 ) {
2649                                 scale *= 10;
2650                                 num = (num*10) + (ch-'0');
2651                         }
2652                 } else {
2653                         break;
2654                 }
2655                 cp++;
2656         }
2657         *cp_p = cp;
2658
2659         /* user says num divided by scale and we say internally that
2660          * is MAX_SCORE * num / scale.
2661          */
2662         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
2663 }
2664
2665 static int diff_scoreopt_parse(const char *opt)
2666 {
2667         int opt1, opt2, cmd;
2668
2669         if (*opt++ != '-')
2670                 return -1;
2671         cmd = *opt++;
2672         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
2673                 return -1; /* that is not a -M, -C nor -B option */
2674
2675         opt1 = parse_num(&opt);
2676         if (cmd != 'B')
2677                 opt2 = 0;
2678         else {
2679                 if (*opt == 0)
2680                         opt2 = 0;
2681                 else if (*opt != '/')
2682                         return -1; /* we expect -B80/99 or -B80 */
2683                 else {
2684                         opt++;
2685                         opt2 = parse_num(&opt);
2686                 }
2687         }
2688         if (*opt != 0)
2689                 return -1;
2690         return opt1 | (opt2 << 16);
2691 }
2692
2693 struct diff_queue_struct diff_queued_diff;
2694
2695 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
2696 {
2697         if (queue->alloc <= queue->nr) {
2698                 queue->alloc = alloc_nr(queue->alloc);
2699                 queue->queue = xrealloc(queue->queue,
2700                                         sizeof(dp) * queue->alloc);
2701         }
2702         queue->queue[queue->nr++] = dp;
2703 }
2704
2705 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
2706                                  struct diff_filespec *one,
2707                                  struct diff_filespec *two)
2708 {
2709         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
2710         dp->one = one;
2711         dp->two = two;
2712         if (queue)
2713                 diff_q(queue, dp);
2714         return dp;
2715 }
2716
2717 void diff_free_filepair(struct diff_filepair *p)
2718 {
2719         free_filespec(p->one);
2720         free_filespec(p->two);
2721         free(p);
2722 }
2723
2724 /* This is different from find_unique_abbrev() in that
2725  * it stuffs the result with dots for alignment.
2726  */
2727 const char *diff_unique_abbrev(const unsigned char *sha1, int len)
2728 {
2729         int abblen;
2730         const char *abbrev;
2731         if (len == 40)
2732                 return sha1_to_hex(sha1);
2733
2734         abbrev = find_unique_abbrev(sha1, len);
2735         abblen = strlen(abbrev);
2736         if (abblen < 37) {
2737                 static char hex[41];
2738                 if (len < abblen && abblen <= len + 2)
2739                         sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
2740                 else
2741                         sprintf(hex, "%s...", abbrev);
2742                 return hex;
2743         }
2744         return sha1_to_hex(sha1);
2745 }
2746
2747 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
2748 {
2749         int line_termination = opt->line_termination;
2750         int inter_name_termination = line_termination ? '\t' : '\0';
2751
2752         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
2753                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
2754                         diff_unique_abbrev(p->one->sha1, opt->abbrev));
2755                 fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
2756         }
2757         if (p->score) {
2758                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
2759                         inter_name_termination);
2760         } else {
2761                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
2762         }
2763
2764         if (p->status == DIFF_STATUS_COPIED ||
2765             p->status == DIFF_STATUS_RENAMED) {
2766                 const char *name_a, *name_b;
2767                 name_a = p->one->path;
2768                 name_b = p->two->path;
2769                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2770                 write_name_quoted(name_a, opt->file, inter_name_termination);
2771                 write_name_quoted(name_b, opt->file, line_termination);
2772         } else {
2773                 const char *name_a, *name_b;
2774                 name_a = p->one->mode ? p->one->path : p->two->path;
2775                 name_b = NULL;
2776                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2777                 write_name_quoted(name_a, opt->file, line_termination);
2778         }
2779 }
2780
2781 int diff_unmodified_pair(struct diff_filepair *p)
2782 {
2783         /* This function is written stricter than necessary to support
2784          * the currently implemented transformers, but the idea is to
2785          * let transformers to produce diff_filepairs any way they want,
2786          * and filter and clean them up here before producing the output.
2787          */
2788         struct diff_filespec *one = p->one, *two = p->two;
2789
2790         if (DIFF_PAIR_UNMERGED(p))
2791                 return 0; /* unmerged is interesting */
2792
2793         /* deletion, addition, mode or type change
2794          * and rename are all interesting.
2795          */
2796         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
2797             DIFF_PAIR_MODE_CHANGED(p) ||
2798             strcmp(one->path, two->path))
2799                 return 0;
2800
2801         /* both are valid and point at the same path.  that is, we are
2802          * dealing with a change.
2803          */
2804         if (one->sha1_valid && two->sha1_valid &&
2805             !hashcmp(one->sha1, two->sha1))
2806                 return 1; /* no change */
2807         if (!one->sha1_valid && !two->sha1_valid)
2808                 return 1; /* both look at the same file on the filesystem. */
2809         return 0;
2810 }
2811
2812 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
2813 {
2814         if (diff_unmodified_pair(p))
2815                 return;
2816
2817         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2818             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2819                 return; /* no tree diffs in patch format */
2820
2821         run_diff(p, o);
2822 }
2823
2824 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
2825                             struct diffstat_t *diffstat)
2826 {
2827         if (diff_unmodified_pair(p))
2828                 return;
2829
2830         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2831             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2832                 return; /* no tree diffs in patch format */
2833
2834         run_diffstat(p, o, diffstat);
2835 }
2836
2837 static void diff_flush_checkdiff(struct diff_filepair *p,
2838                 struct diff_options *o)
2839 {
2840         if (diff_unmodified_pair(p))
2841                 return;
2842
2843         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2844             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2845                 return; /* no tree diffs in patch format */
2846
2847         run_checkdiff(p, o);
2848 }
2849
2850 int diff_queue_is_empty(void)
2851 {
2852         struct diff_queue_struct *q = &diff_queued_diff;
2853         int i;
2854         for (i = 0; i < q->nr; i++)
2855                 if (!diff_unmodified_pair(q->queue[i]))
2856                         return 0;
2857         return 1;
2858 }
2859
2860 #if DIFF_DEBUG
2861 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
2862 {
2863         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
2864                 x, one ? one : "",
2865                 s->path,
2866                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
2867                 s->mode,
2868                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
2869         fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
2870                 x, one ? one : "",
2871                 s->size, s->xfrm_flags);
2872 }
2873
2874 void diff_debug_filepair(const struct diff_filepair *p, int i)
2875 {
2876         diff_debug_filespec(p->one, i, "one");
2877         diff_debug_filespec(p->two, i, "two");
2878         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
2879                 p->score, p->status ? p->status : '?',
2880                 p->one->rename_used, p->broken_pair);
2881 }
2882
2883 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
2884 {
2885         int i;
2886         if (msg)
2887                 fprintf(stderr, "%s\n", msg);
2888         fprintf(stderr, "q->nr = %d\n", q->nr);
2889         for (i = 0; i < q->nr; i++) {
2890                 struct diff_filepair *p = q->queue[i];
2891                 diff_debug_filepair(p, i);
2892         }
2893 }
2894 #endif
2895
2896 static void diff_resolve_rename_copy(void)
2897 {
2898         int i;
2899         struct diff_filepair *p;
2900         struct diff_queue_struct *q = &diff_queued_diff;
2901
2902         diff_debug_queue("resolve-rename-copy", q);
2903
2904         for (i = 0; i < q->nr; i++) {
2905                 p = q->queue[i];
2906                 p->status = 0; /* undecided */
2907                 if (DIFF_PAIR_UNMERGED(p))
2908                         p->status = DIFF_STATUS_UNMERGED;
2909                 else if (!DIFF_FILE_VALID(p->one))
2910                         p->status = DIFF_STATUS_ADDED;
2911                 else if (!DIFF_FILE_VALID(p->two))
2912                         p->status = DIFF_STATUS_DELETED;
2913                 else if (DIFF_PAIR_TYPE_CHANGED(p))
2914                         p->status = DIFF_STATUS_TYPE_CHANGED;
2915
2916                 /* from this point on, we are dealing with a pair
2917                  * whose both sides are valid and of the same type, i.e.
2918                  * either in-place edit or rename/copy edit.
2919                  */
2920                 else if (DIFF_PAIR_RENAME(p)) {
2921                         /*
2922                          * A rename might have re-connected a broken
2923                          * pair up, causing the pathnames to be the
2924                          * same again. If so, that's not a rename at
2925                          * all, just a modification..
2926                          *
2927                          * Otherwise, see if this source was used for
2928                          * multiple renames, in which case we decrement
2929                          * the count, and call it a copy.
2930                          */
2931                         if (!strcmp(p->one->path, p->two->path))
2932                                 p->status = DIFF_STATUS_MODIFIED;
2933                         else if (--p->one->rename_used > 0)
2934                                 p->status = DIFF_STATUS_COPIED;
2935                         else
2936                                 p->status = DIFF_STATUS_RENAMED;
2937                 }
2938                 else if (hashcmp(p->one->sha1, p->two->sha1) ||
2939                          p->one->mode != p->two->mode ||
2940                          is_null_sha1(p->one->sha1))
2941                         p->status = DIFF_STATUS_MODIFIED;
2942                 else {
2943                         /* This is a "no-change" entry and should not
2944                          * happen anymore, but prepare for broken callers.
2945                          */
2946                         error("feeding unmodified %s to diffcore",
2947                               p->one->path);
2948                         p->status = DIFF_STATUS_UNKNOWN;
2949                 }
2950         }
2951         diff_debug_queue("resolve-rename-copy done", q);
2952 }
2953
2954 static int check_pair_status(struct diff_filepair *p)
2955 {
2956         switch (p->status) {
2957         case DIFF_STATUS_UNKNOWN:
2958                 return 0;
2959         case 0:
2960                 die("internal error in diff-resolve-rename-copy");
2961         default:
2962                 return 1;
2963         }
2964 }
2965
2966 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
2967 {
2968         int fmt = opt->output_format;
2969
2970         if (fmt & DIFF_FORMAT_CHECKDIFF)
2971                 diff_flush_checkdiff(p, opt);
2972         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
2973                 diff_flush_raw(p, opt);
2974         else if (fmt & DIFF_FORMAT_NAME) {
2975                 const char *name_a, *name_b;
2976                 name_a = p->two->path;
2977                 name_b = NULL;
2978                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2979                 write_name_quoted(name_a, opt->file, opt->line_termination);
2980         }
2981 }
2982
2983 static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
2984 {
2985         if (fs->mode)
2986                 fprintf(file, " %s mode %06o ", newdelete, fs->mode);
2987         else
2988                 fprintf(file, " %s ", newdelete);
2989         write_name_quoted(fs->path, file, '\n');
2990 }
2991
2992
2993 static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name)
2994 {
2995         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
2996                 fprintf(file, " mode change %06o => %06o%c", p->one->mode, p->two->mode,
2997                         show_name ? ' ' : '\n');
2998                 if (show_name) {
2999                         write_name_quoted(p->two->path, file, '\n');
3000                 }
3001         }
3002 }
3003
3004 static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p)
3005 {
3006         char *names = pprint_rename(p->one->path, p->two->path);
3007
3008         fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
3009         free(names);
3010         show_mode_change(file, p, 0);
3011 }
3012
3013 static void diff_summary(FILE *file, struct diff_filepair *p)
3014 {
3015         switch(p->status) {
3016         case DIFF_STATUS_DELETED:
3017                 show_file_mode_name(file, "delete", p->one);
3018                 break;
3019         case DIFF_STATUS_ADDED:
3020                 show_file_mode_name(file, "create", p->two);
3021                 break;
3022         case DIFF_STATUS_COPIED:
3023                 show_rename_copy(file, "copy", p);
3024                 break;
3025         case DIFF_STATUS_RENAMED:
3026                 show_rename_copy(file, "rename", p);
3027                 break;
3028         default:
3029                 if (p->score) {
3030                         fputs(" rewrite ", file);
3031                         write_name_quoted(p->two->path, file, ' ');
3032                         fprintf(file, "(%d%%)\n", similarity_index(p));
3033                 }
3034                 show_mode_change(file, p, !p->score);
3035                 break;
3036         }
3037 }
3038
3039 struct patch_id_t {
3040         struct xdiff_emit_state xm;
3041         SHA_CTX *ctx;
3042         int patchlen;
3043 };
3044
3045 static int remove_space(char *line, int len)
3046 {
3047         int i;
3048         char *dst = line;
3049         unsigned char c;
3050
3051         for (i = 0; i < len; i++)
3052                 if (!isspace((c = line[i])))
3053                         *dst++ = c;
3054
3055         return dst - line;
3056 }
3057
3058 static void patch_id_consume(void *priv, char *line, unsigned long len)
3059 {
3060         struct patch_id_t *data = priv;
3061         int new_len;
3062
3063         /* Ignore line numbers when computing the SHA1 of the patch */
3064         if (!prefixcmp(line, "@@ -"))
3065                 return;
3066
3067         new_len = remove_space(line, len);
3068
3069         SHA1_Update(data->ctx, line, new_len);
3070         data->patchlen += new_len;
3071 }
3072
3073 /* returns 0 upon success, and writes result into sha1 */
3074 static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
3075 {
3076         struct diff_queue_struct *q = &diff_queued_diff;
3077         int i;
3078         SHA_CTX ctx;
3079         struct patch_id_t data;
3080         char buffer[PATH_MAX * 4 + 20];
3081
3082         SHA1_Init(&ctx);
3083         memset(&data, 0, sizeof(struct patch_id_t));
3084         data.ctx = &ctx;
3085         data.xm.consume = patch_id_consume;
3086
3087         for (i = 0; i < q->nr; i++) {
3088                 xpparam_t xpp;
3089                 xdemitconf_t xecfg;
3090                 xdemitcb_t ecb;
3091                 mmfile_t mf1, mf2;
3092                 struct diff_filepair *p = q->queue[i];
3093                 int len1, len2;
3094
3095                 memset(&xecfg, 0, sizeof(xecfg));
3096                 if (p->status == 0)
3097                         return error("internal diff status error");
3098                 if (p->status == DIFF_STATUS_UNKNOWN)
3099                         continue;
3100                 if (diff_unmodified_pair(p))
3101                         continue;
3102                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3103                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3104                         continue;
3105                 if (DIFF_PAIR_UNMERGED(p))
3106                         continue;
3107
3108                 diff_fill_sha1_info(p->one);
3109                 diff_fill_sha1_info(p->two);
3110                 if (fill_mmfile(&mf1, p->one) < 0 ||
3111                                 fill_mmfile(&mf2, p->two) < 0)
3112                         return error("unable to read files to diff");
3113
3114                 len1 = remove_space(p->one->path, strlen(p->one->path));
3115                 len2 = remove_space(p->two->path, strlen(p->two->path));
3116                 if (p->one->mode == 0)
3117                         len1 = snprintf(buffer, sizeof(buffer),
3118                                         "diff--gita/%.*sb/%.*s"
3119                                         "newfilemode%06o"
3120                                         "---/dev/null"
3121                                         "+++b/%.*s",
3122                                         len1, p->one->path,
3123                                         len2, p->two->path,
3124                                         p->two->mode,
3125                                         len2, p->two->path);
3126                 else if (p->two->mode == 0)
3127                         len1 = snprintf(buffer, sizeof(buffer),
3128                                         "diff--gita/%.*sb/%.*s"
3129                                         "deletedfilemode%06o"
3130                                         "---a/%.*s"
3131                                         "+++/dev/null",
3132                                         len1, p->one->path,
3133                                         len2, p->two->path,
3134                                         p->one->mode,
3135                                         len1, p->one->path);
3136                 else
3137                         len1 = snprintf(buffer, sizeof(buffer),
3138                                         "diff--gita/%.*sb/%.*s"
3139                                         "---a/%.*s"
3140                                         "+++b/%.*s",
3141                                         len1, p->one->path,
3142                                         len2, p->two->path,
3143                                         len1, p->one->path,
3144                                         len2, p->two->path);
3145                 SHA1_Update(&ctx, buffer, len1);
3146
3147                 xpp.flags = XDF_NEED_MINIMAL;
3148                 xecfg.ctxlen = 3;
3149                 xecfg.flags = XDL_EMIT_FUNCNAMES;
3150                 ecb.outf = xdiff_outf;
3151                 ecb.priv = &data;
3152                 xdi_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
3153         }
3154
3155         SHA1_Final(sha1, &ctx);
3156         return 0;
3157 }
3158
3159 int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
3160 {
3161         struct diff_queue_struct *q = &diff_queued_diff;
3162         int i;
3163         int result = diff_get_patch_id(options, sha1);
3164
3165         for (i = 0; i < q->nr; i++)
3166                 diff_free_filepair(q->queue[i]);
3167
3168         free(q->queue);
3169         q->queue = NULL;
3170         q->nr = q->alloc = 0;
3171
3172         return result;
3173 }
3174
3175 static int is_summary_empty(const struct diff_queue_struct *q)
3176 {
3177         int i;
3178
3179         for (i = 0; i < q->nr; i++) {
3180                 const struct diff_filepair *p = q->queue[i];
3181
3182                 switch (p->status) {
3183                 case DIFF_STATUS_DELETED:
3184                 case DIFF_STATUS_ADDED:
3185                 case DIFF_STATUS_COPIED:
3186                 case DIFF_STATUS_RENAMED:
3187                         return 0;
3188                 default:
3189                         if (p->score)
3190                                 return 0;
3191                         if (p->one->mode && p->two->mode &&
3192                             p->one->mode != p->two->mode)
3193                                 return 0;
3194                         break;
3195                 }
3196         }
3197         return 1;
3198 }
3199
3200 void diff_flush(struct diff_options *options)
3201 {
3202         struct diff_queue_struct *q = &diff_queued_diff;
3203         int i, output_format = options->output_format;
3204         int separator = 0;
3205
3206         /*
3207          * Order: raw, stat, summary, patch
3208          * or:    name/name-status/checkdiff (other bits clear)
3209          */
3210         if (!q->nr)
3211                 goto free_queue;
3212
3213         if (output_format & (DIFF_FORMAT_RAW |
3214                              DIFF_FORMAT_NAME |
3215                              DIFF_FORMAT_NAME_STATUS |
3216                              DIFF_FORMAT_CHECKDIFF)) {
3217                 for (i = 0; i < q->nr; i++) {
3218                         struct diff_filepair *p = q->queue[i];
3219                         if (check_pair_status(p))
3220                                 flush_one_pair(p, options);
3221                 }
3222                 separator++;
3223         }
3224
3225         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT)) {
3226                 struct diffstat_t diffstat;
3227
3228                 memset(&diffstat, 0, sizeof(struct diffstat_t));
3229                 diffstat.xm.consume = diffstat_consume;
3230                 for (i = 0; i < q->nr; i++) {
3231                         struct diff_filepair *p = q->queue[i];
3232                         if (check_pair_status(p))
3233                                 diff_flush_stat(p, options, &diffstat);
3234                 }
3235                 if (output_format & DIFF_FORMAT_NUMSTAT)
3236                         show_numstat(&diffstat, options);
3237                 if (output_format & DIFF_FORMAT_DIFFSTAT)
3238                         show_stats(&diffstat, options);
3239                 if (output_format & DIFF_FORMAT_SHORTSTAT)
3240                         show_shortstats(&diffstat, options);
3241                 free_diffstat_info(&diffstat);
3242                 separator++;
3243         }
3244         if (output_format & DIFF_FORMAT_DIRSTAT)
3245                 show_dirstat(options);
3246
3247         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
3248                 for (i = 0; i < q->nr; i++)
3249                         diff_summary(options->file, q->queue[i]);
3250                 separator++;
3251         }
3252
3253         if (output_format & DIFF_FORMAT_PATCH) {
3254                 if (separator) {
3255                         putc(options->line_termination, options->file);
3256                         if (options->stat_sep) {
3257                                 /* attach patch instead of inline */
3258                                 fputs(options->stat_sep, options->file);
3259                         }
3260                 }
3261
3262                 for (i = 0; i < q->nr; i++) {
3263                         struct diff_filepair *p = q->queue[i];
3264                         if (check_pair_status(p))
3265                                 diff_flush_patch(p, options);
3266                 }
3267         }
3268
3269         if (output_format & DIFF_FORMAT_CALLBACK)
3270                 options->format_callback(q, options, options->format_callback_data);
3271
3272         for (i = 0; i < q->nr; i++)
3273                 diff_free_filepair(q->queue[i]);
3274 free_queue:
3275         free(q->queue);
3276         q->queue = NULL;
3277         q->nr = q->alloc = 0;
3278         if (options->close_file)
3279                 fclose(options->file);
3280 }
3281
3282 static void diffcore_apply_filter(const char *filter)
3283 {
3284         int i;
3285         struct diff_queue_struct *q = &diff_queued_diff;
3286         struct diff_queue_struct outq;
3287         outq.queue = NULL;
3288         outq.nr = outq.alloc = 0;
3289
3290         if (!filter)
3291                 return;
3292
3293         if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
3294                 int found;
3295                 for (i = found = 0; !found && i < q->nr; i++) {
3296                         struct diff_filepair *p = q->queue[i];
3297                         if (((p->status == DIFF_STATUS_MODIFIED) &&
3298                              ((p->score &&
3299                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
3300                               (!p->score &&
3301                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
3302                             ((p->status != DIFF_STATUS_MODIFIED) &&
3303                              strchr(filter, p->status)))
3304                                 found++;
3305                 }
3306                 if (found)
3307                         return;
3308
3309                 /* otherwise we will clear the whole queue
3310                  * by copying the empty outq at the end of this
3311                  * function, but first clear the current entries
3312                  * in the queue.
3313                  */
3314                 for (i = 0; i < q->nr; i++)
3315                         diff_free_filepair(q->queue[i]);
3316         }
3317         else {
3318                 /* Only the matching ones */
3319                 for (i = 0; i < q->nr; i++) {
3320                         struct diff_filepair *p = q->queue[i];
3321
3322                         if (((p->status == DIFF_STATUS_MODIFIED) &&
3323                              ((p->score &&
3324                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
3325                               (!p->score &&
3326                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
3327                             ((p->status != DIFF_STATUS_MODIFIED) &&
3328                              strchr(filter, p->status)))
3329                                 diff_q(&outq, p);
3330                         else
3331                                 diff_free_filepair(p);
3332                 }
3333         }
3334         free(q->queue);
3335         *q = outq;
3336 }
3337
3338 /* Check whether two filespecs with the same mode and size are identical */
3339 static int diff_filespec_is_identical(struct diff_filespec *one,
3340                                       struct diff_filespec *two)
3341 {
3342         if (S_ISGITLINK(one->mode))
3343                 return 0;
3344         if (diff_populate_filespec(one, 0))
3345                 return 0;
3346         if (diff_populate_filespec(two, 0))
3347                 return 0;
3348         return !memcmp(one->data, two->data, one->size);
3349 }
3350
3351 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
3352 {
3353         int i;
3354         struct diff_queue_struct *q = &diff_queued_diff;
3355         struct diff_queue_struct outq;
3356         outq.queue = NULL;
3357         outq.nr = outq.alloc = 0;
3358
3359         for (i = 0; i < q->nr; i++) {
3360                 struct diff_filepair *p = q->queue[i];
3361
3362                 /*
3363                  * 1. Entries that come from stat info dirtyness
3364                  *    always have both sides (iow, not create/delete),
3365                  *    one side of the object name is unknown, with
3366                  *    the same mode and size.  Keep the ones that
3367                  *    do not match these criteria.  They have real
3368                  *    differences.
3369                  *
3370                  * 2. At this point, the file is known to be modified,
3371                  *    with the same mode and size, and the object
3372                  *    name of one side is unknown.  Need to inspect
3373                  *    the identical contents.
3374                  */
3375                 if (!DIFF_FILE_VALID(p->one) || /* (1) */
3376                     !DIFF_FILE_VALID(p->two) ||
3377                     (p->one->sha1_valid && p->two->sha1_valid) ||
3378                     (p->one->mode != p->two->mode) ||
3379                     diff_populate_filespec(p->one, 1) ||
3380                     diff_populate_filespec(p->two, 1) ||
3381                     (p->one->size != p->two->size) ||
3382                     !diff_filespec_is_identical(p->one, p->two)) /* (2) */
3383                         diff_q(&outq, p);
3384                 else {
3385                         /*
3386                          * The caller can subtract 1 from skip_stat_unmatch
3387                          * to determine how many paths were dirty only
3388                          * due to stat info mismatch.
3389                          */
3390                         if (!DIFF_OPT_TST(diffopt, NO_INDEX))
3391                                 diffopt->skip_stat_unmatch++;
3392                         diff_free_filepair(p);
3393                 }
3394         }
3395         free(q->queue);
3396         *q = outq;
3397 }
3398
3399 void diffcore_std(struct diff_options *options)
3400 {
3401         if (DIFF_OPT_TST(options, QUIET))
3402                 return;
3403
3404         if (options->skip_stat_unmatch && !DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3405                 diffcore_skip_stat_unmatch(options);
3406         if (options->break_opt != -1)
3407                 diffcore_break(options->break_opt);
3408         if (options->detect_rename)
3409                 diffcore_rename(options);
3410         if (options->break_opt != -1)
3411                 diffcore_merge_broken();
3412         if (options->pickaxe)
3413                 diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
3414         if (options->orderfile)
3415                 diffcore_order(options->orderfile);
3416         diff_resolve_rename_copy();
3417         diffcore_apply_filter(options->filter);
3418
3419         if (diff_queued_diff.nr)
3420                 DIFF_OPT_SET(options, HAS_CHANGES);
3421         else
3422                 DIFF_OPT_CLR(options, HAS_CHANGES);
3423 }
3424
3425 int diff_result_code(struct diff_options *opt, int status)
3426 {
3427         int result = 0;
3428         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
3429             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
3430                 return status;
3431         if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
3432             DIFF_OPT_TST(opt, HAS_CHANGES))
3433                 result |= 01;
3434         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
3435             DIFF_OPT_TST(opt, CHECK_FAILED))
3436                 result |= 02;
3437         return result;
3438 }
3439
3440 void diff_addremove(struct diff_options *options,
3441                     int addremove, unsigned mode,
3442                     const unsigned char *sha1,
3443                     const char *concatpath)
3444 {
3445         struct diff_filespec *one, *two;
3446
3447         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES) && S_ISGITLINK(mode))
3448                 return;
3449
3450         /* This may look odd, but it is a preparation for
3451          * feeding "there are unchanged files which should
3452          * not produce diffs, but when you are doing copy
3453          * detection you would need them, so here they are"
3454          * entries to the diff-core.  They will be prefixed
3455          * with something like '=' or '*' (I haven't decided
3456          * which but should not make any difference).
3457          * Feeding the same new and old to diff_change()
3458          * also has the same effect.
3459          * Before the final output happens, they are pruned after
3460          * merged into rename/copy pairs as appropriate.
3461          */
3462         if (DIFF_OPT_TST(options, REVERSE_DIFF))
3463                 addremove = (addremove == '+' ? '-' :
3464                              addremove == '-' ? '+' : addremove);
3465
3466         if (options->prefix &&
3467             strncmp(concatpath, options->prefix, options->prefix_length))
3468                 return;
3469
3470         one = alloc_filespec(concatpath);
3471         two = alloc_filespec(concatpath);
3472
3473         if (addremove != '+')
3474                 fill_filespec(one, sha1, mode);
3475         if (addremove != '-')
3476                 fill_filespec(two, sha1, mode);
3477
3478         diff_queue(&diff_queued_diff, one, two);
3479         DIFF_OPT_SET(options, HAS_CHANGES);
3480 }
3481
3482 void diff_change(struct diff_options *options,
3483                  unsigned old_mode, unsigned new_mode,
3484                  const unsigned char *old_sha1,
3485                  const unsigned char *new_sha1,
3486                  const char *concatpath)
3487 {
3488         struct diff_filespec *one, *two;
3489
3490         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES) && S_ISGITLINK(old_mode)
3491                         && S_ISGITLINK(new_mode))
3492                 return;
3493
3494         if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
3495                 unsigned tmp;
3496                 const unsigned char *tmp_c;
3497                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
3498                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
3499         }
3500
3501         if (options->prefix &&
3502             strncmp(concatpath, options->prefix, options->prefix_length))
3503                 return;
3504
3505         one = alloc_filespec(concatpath);
3506         two = alloc_filespec(concatpath);
3507         fill_filespec(one, old_sha1, old_mode);
3508         fill_filespec(two, new_sha1, new_mode);
3509
3510         diff_queue(&diff_queued_diff, one, two);
3511         DIFF_OPT_SET(options, HAS_CHANGES);
3512 }
3513
3514 void diff_unmerge(struct diff_options *options,
3515                   const char *path,
3516                   unsigned mode, const unsigned char *sha1)
3517 {
3518         struct diff_filespec *one, *two;
3519
3520         if (options->prefix &&
3521             strncmp(path, options->prefix, options->prefix_length))
3522                 return;
3523
3524         one = alloc_filespec(path);
3525         two = alloc_filespec(path);
3526         fill_filespec(one, sha1, mode);
3527         diff_queue(&diff_queued_diff, one, two)->is_unmerged = 1;
3528 }