git.oblomov.eu Git - git/blob - diff.c

   1 /*
   2  * Copyright (C) 2005 Junio C Hamano
   3  */
   4 #include "cache.h"
   5 #include "quote.h"
   6 #include "diff.h"
   7 #include "diffcore.h"
   8 #include "delta.h"
   9 #include "xdiff-interface.h"
  10 #include "color.h"
  11 #include "attr.h"
  12 #include "run-command.h"
  13 #include "utf8.h"
  14
  15 #ifdef NO_FAST_WORKING_DIRECTORY
  16 #define FAST_WORKING_DIRECTORY 0
  17 #else
  18 #define FAST_WORKING_DIRECTORY 1
  19 #endif
  20
  21 static int diff_detect_rename_default;
  22 static int diff_rename_limit_default = 200;
  23 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.renamelimit")) {
 135                 diff_rename_limit_default = git_config_int(var, value);
 136                 return 0;
 137         }
 138         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 139                 diff_use_color_default = git_config_colorbool(var, value, -1);
 140                 return 0;
 141         }
 142         if (!strcmp(var, "diff.renames")) {
 143                 if (!value)
 144                         diff_detect_rename_default = DIFF_DETECT_RENAME;
 145                 else if (!strcasecmp(value, "copies") ||
 146                          !strcasecmp(value, "copy"))
 147                         diff_detect_rename_default = DIFF_DETECT_COPY;
 148                 else if (git_config_bool(var,value))
 149                         diff_detect_rename_default = DIFF_DETECT_RENAME;
 150                 return 0;
 151         }
 152         if (!strcmp(var, "diff.autorefreshindex")) {
 153                 diff_auto_refresh_index = git_config_bool(var, value);
 154                 return 0;
 155         }
 156         if (!strcmp(var, "diff.external")) {
 157                 if (!value)
 158                         return config_error_nonbool(var);
 159                 external_diff_cmd_cfg = xstrdup(value);
 160                 return 0;
 161         }
 162         if (!prefixcmp(var, "diff.")) {
 163                 const char *ep = strrchr(var, '.');
 164
 165                 if (ep != var + 4 && !strcmp(ep, ".command"))
 166                         return parse_lldiff_command(var, ep, value);
 167         }
 168
 169         return git_diff_basic_config(var, value, cb);
 170 }
 171
 172 int git_diff_basic_config(const char *var, const char *value, void *cb)
 173 {
 174         if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
 175                 int slot = parse_diff_color_slot(var, 11);
 176                 if (!value)
 177                         return config_error_nonbool(var);
 178                 color_parse(value, var, diff_colors[slot]);
 179                 return 0;
 180         }
 181
 182         if (!prefixcmp(var, "diff.")) {
 183                 const char *ep = strrchr(var, '.');
 184                 if (ep != var + 4) {
 185                         if (!strcmp(ep, ".funcname")) {
 186                                 if (!value)
 187                                         return config_error_nonbool(var);
 188                                 return parse_funcname_pattern(var, ep, value);
 189                         }
 190                 }
 191         }
 192
 193         return git_color_default_config(var, value, cb);
 194 }
 195
 196 static char *quote_two(const char *one, const char *two)
 197 {
 198         int need_one = quote_c_style(one, NULL, NULL, 1);
 199         int need_two = quote_c_style(two, NULL, NULL, 1);
 200         struct strbuf res;
 201
 202         strbuf_init(&res, 0);
 203         if (need_one + need_two) {
 204                 strbuf_addch(&res, '"');
 205                 quote_c_style(one, &res, NULL, 1);
 206                 quote_c_style(two, &res, NULL, 1);
 207                 strbuf_addch(&res, '"');
 208         } else {
 209                 strbuf_addstr(&res, one);
 210                 strbuf_addstr(&res, two);
 211         }
 212         return strbuf_detach(&res, NULL);
 213 }
 214
 215 static const char *external_diff(void)
 216 {
 217         static const char *external_diff_cmd = NULL;
 218         static int done_preparing = 0;
 219
 220         if (done_preparing)
 221                 return external_diff_cmd;
 222         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 223         if (!external_diff_cmd)
 224                 external_diff_cmd = external_diff_cmd_cfg;
 225         done_preparing = 1;
 226         return external_diff_cmd;
 227 }
 228
 229 static struct diff_tempfile {
 230         const char *name; /* filename external diff should read from */
 231         char hex[41];
 232         char mode[10];
 233         char tmp_path[PATH_MAX];
 234 } diff_temp[2];
 235
 236 static int count_lines(const char *data, int size)
 237 {
 238         int count, ch, completely_empty = 1, nl_just_seen = 0;
 239         count = 0;
 240         while (0 < size--) {
 241                 ch = *data++;
 242                 if (ch == '\n') {
 243                         count++;
 244                         nl_just_seen = 1;
 245                         completely_empty = 0;
 246                 }
 247                 else {
 248                         nl_just_seen = 0;
 249                         completely_empty = 0;
 250                 }
 251         }
 252         if (completely_empty)
 253                 return 0;
 254         if (!nl_just_seen)
 255                 count++; /* no trailing newline */
 256         return count;
 257 }
 258
 259 static void print_line_count(FILE *file, int count)
 260 {
 261         switch (count) {
 262         case 0:
 263                 fprintf(file, "0,0");
 264                 break;
 265         case 1:
 266                 fprintf(file, "1");
 267                 break;
 268         default:
 269                 fprintf(file, "1,%d", count);
 270                 break;
 271         }
 272 }
 273
 274 static void copy_file_with_prefix(FILE *file,
 275                                   int prefix, const char *data, int size,
 276                                   const char *set, const char *reset)
 277 {
 278         int ch, nl_just_seen = 1;
 279         while (0 < size--) {
 280                 ch = *data++;
 281                 if (nl_just_seen) {
 282                         fputs(set, file);
 283                         putc(prefix, file);
 284                 }
 285                 if (ch == '\n') {
 286                         nl_just_seen = 1;
 287                         fputs(reset, file);
 288                 } else
 289                         nl_just_seen = 0;
 290                 putc(ch, file);
 291         }
 292         if (!nl_just_seen)
 293                 fprintf(file, "%s\n\\ No newline at end of file\n", reset);
 294 }
 295
 296 static void emit_rewrite_diff(const char *name_a,
 297                               const char *name_b,
 298                               struct diff_filespec *one,
 299                               struct diff_filespec *two,
 300                               struct diff_options *o)
 301 {
 302         int lc_a, lc_b;
 303         int color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
 304         const char *name_a_tab, *name_b_tab;
 305         const char *metainfo = diff_get_color(color_diff, DIFF_METAINFO);
 306         const char *fraginfo = diff_get_color(color_diff, DIFF_FRAGINFO);
 307         const char *old = diff_get_color(color_diff, DIFF_FILE_OLD);
 308         const char *new = diff_get_color(color_diff, DIFF_FILE_NEW);
 309         const char *reset = diff_get_color(color_diff, DIFF_RESET);
 310         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 311
 312         name_a += (*name_a == '/');
 313         name_b += (*name_b == '/');
 314         name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 315         name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 316
 317         strbuf_reset(&a_name);
 318         strbuf_reset(&b_name);
 319         quote_two_c_style(&a_name, o->a_prefix, name_a, 0);
 320         quote_two_c_style(&b_name, o->b_prefix, name_b, 0);
 321
 322         diff_populate_filespec(one, 0);
 323         diff_populate_filespec(two, 0);
 324         lc_a = count_lines(one->data, one->size);
 325         lc_b = count_lines(two->data, two->size);
 326         fprintf(o->file,
 327                 "%s--- %s%s%s\n%s+++ %s%s%s\n%s@@ -",
 328                 metainfo, a_name.buf, name_a_tab, reset,
 329                 metainfo, b_name.buf, name_b_tab, reset, fraginfo);
 330         print_line_count(o->file, lc_a);
 331         fprintf(o->file, " +");
 332         print_line_count(o->file, lc_b);
 333         fprintf(o->file, " @@%s\n", reset);
 334         if (lc_a)
 335                 copy_file_with_prefix(o->file, '-', one->data, one->size, old, reset);
 336         if (lc_b)
 337                 copy_file_with_prefix(o->file, '+', two->data, two->size, new, reset);
 338 }
 339
 340 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 341 {
 342         if (!DIFF_FILE_VALID(one)) {
 343                 mf->ptr = (char *)""; /* does not matter */
 344                 mf->size = 0;
 345                 return 0;
 346         }
 347         else if (diff_populate_filespec(one, 0))
 348                 return -1;
 349         mf->ptr = one->data;
 350         mf->size = one->size;
 351         return 0;
 352 }
 353
 354 struct diff_words_buffer {
 355         mmfile_t text;
 356         long alloc;
 357         long current; /* output pointer */
 358         int suppressed_newline;
 359 };
 360
 361 static void diff_words_append(char *line, unsigned long len,
 362                 struct diff_words_buffer *buffer)
 363 {
 364         if (buffer->text.size + len > buffer->alloc) {
 365                 buffer->alloc = (buffer->text.size + len) * 3 / 2;
 366                 buffer->text.ptr = xrealloc(buffer->text.ptr, buffer->alloc);
 367         }
 368         line++;
 369         len--;
 370         memcpy(buffer->text.ptr + buffer->text.size, line, len);
 371         buffer->text.size += len;
 372 }
 373
 374 struct diff_words_data {
 375         struct xdiff_emit_state xm;
 376         struct diff_words_buffer minus, plus;
 377         FILE *file;
 378 };
 379
 380 static void print_word(FILE *file, struct diff_words_buffer *buffer, int len, int color,
 381                 int suppress_newline)
 382 {
 383         const char *ptr;
 384         int eol = 0;
 385
 386         if (len == 0)
 387                 return;
 388
 389         ptr  = buffer->text.ptr + buffer->current;
 390         buffer->current += len;
 391
 392         if (ptr[len - 1] == '\n') {
 393                 eol = 1;
 394                 len--;
 395         }
 396
 397         fputs(diff_get_color(1, color), file);
 398         fwrite(ptr, len, 1, file);
 399         fputs(diff_get_color(1, DIFF_RESET), file);
 400
 401         if (eol) {
 402                 if (suppress_newline)
 403                         buffer->suppressed_newline = 1;
 404                 else
 405                         putc('\n', file);
 406         }
 407 }
 408
 409 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 410 {
 411         struct diff_words_data *diff_words = priv;
 412
 413         if (diff_words->minus.suppressed_newline) {
 414                 if (line[0] != '+')
 415                         putc('\n', diff_words->file);
 416                 diff_words->minus.suppressed_newline = 0;
 417         }
 418
 419         len--;
 420         switch (line[0]) {
 421                 case '-':
 422                         print_word(diff_words->file,
 423                                    &diff_words->minus, len, DIFF_FILE_OLD, 1);
 424                         break;
 425                 case '+':
 426                         print_word(diff_words->file,
 427                                    &diff_words->plus, len, DIFF_FILE_NEW, 0);
 428                         break;
 429                 case ' ':
 430                         print_word(diff_words->file,
 431                                    &diff_words->plus, len, DIFF_PLAIN, 0);
 432                         diff_words->minus.current += len;
 433                         break;
 434         }
 435 }
 436
 437 /* this executes the word diff on the accumulated buffers */
 438 static void diff_words_show(struct diff_words_data *diff_words)
 439 {
 440         xpparam_t xpp;
 441         xdemitconf_t xecfg;
 442         xdemitcb_t ecb;
 443         mmfile_t minus, plus;
 444         int i;
 445
 446         memset(&xecfg, 0, sizeof(xecfg));
 447         minus.size = diff_words->minus.text.size;
 448         minus.ptr = xmalloc(minus.size);
 449         memcpy(minus.ptr, diff_words->minus.text.ptr, minus.size);
 450         for (i = 0; i < minus.size; i++)
 451                 if (isspace(minus.ptr[i]))
 452                         minus.ptr[i] = '\n';
 453         diff_words->minus.current = 0;
 454
 455         plus.size = diff_words->plus.text.size;
 456         plus.ptr = xmalloc(plus.size);
 457         memcpy(plus.ptr, diff_words->plus.text.ptr, plus.size);
 458         for (i = 0; i < plus.size; i++)
 459                 if (isspace(plus.ptr[i]))
 460                         plus.ptr[i] = '\n';
 461         diff_words->plus.current = 0;
 462
 463         xpp.flags = XDF_NEED_MINIMAL;
 464         xecfg.ctxlen = diff_words->minus.alloc + diff_words->plus.alloc;
 465         ecb.outf = xdiff_outf;
 466         ecb.priv = diff_words;
 467         diff_words->xm.consume = fn_out_diff_words_aux;
 468         xdi_diff(&minus, &plus, &xpp, &xecfg, &ecb);
 469
 470         free(minus.ptr);
 471         free(plus.ptr);
 472         diff_words->minus.text.size = diff_words->plus.text.size = 0;
 473
 474         if (diff_words->minus.suppressed_newline) {
 475                 putc('\n', diff_words->file);
 476                 diff_words->minus.suppressed_newline = 0;
 477         }
 478 }
 479
 480 typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 481
 482 struct emit_callback {
 483         struct xdiff_emit_state xm;
 484         int nparents, color_diff;
 485         unsigned ws_rule;
 486         sane_truncate_fn truncate;
 487         const char **label_path;
 488         struct diff_words_data *diff_words;
 489         int *found_changesp;
 490         FILE *file;
 491 };
 492
 493 static void free_diff_words_data(struct emit_callback *ecbdata)
 494 {
 495         if (ecbdata->diff_words) {
 496                 /* flush buffers */
 497                 if (ecbdata->diff_words->minus.text.size ||
 498                                 ecbdata->diff_words->plus.text.size)
 499                         diff_words_show(ecbdata->diff_words);
 500
 501                 free (ecbdata->diff_words->minus.text.ptr);
 502                 free (ecbdata->diff_words->plus.text.ptr);
 503                 free(ecbdata->diff_words);
 504                 ecbdata->diff_words = NULL;
 505         }
 506 }
 507
 508 const char *diff_get_color(int diff_use_color, enum color_diff ix)
 509 {
 510         if (diff_use_color)
 511                 return diff_colors[ix];
 512         return "";
 513 }
 514
 515 static void emit_line(FILE *file, const char *set, const char *reset, const char *line, int len)
 516 {
 517         int has_trailing_newline = (len > 0 && line[len-1] == '\n');
 518         if (has_trailing_newline)
 519                 len--;
 520
 521         fputs(set, file);
 522         fwrite(line, len, 1, file);
 523         fputs(reset, file);
 524         if (has_trailing_newline)
 525                 fputc('\n', file);
 526 }
 527
 528 static void emit_add_line(const char *reset, struct emit_callback *ecbdata, const char *line, int len)
 529 {
 530         const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 531         const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
 532
 533         if (!*ws)
 534                 emit_line(ecbdata->file, set, reset, line, len);
 535         else {
 536                 /* Emit just the prefix, then the rest. */
 537                 emit_line(ecbdata->file, set, reset, line, ecbdata->nparents);
 538                 (void)check_and_emit_line(line + ecbdata->nparents,
 539                     len - ecbdata->nparents, ecbdata->ws_rule,
 540                     ecbdata->file, set, reset, ws);
 541         }
 542 }
 543
 544 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
 545 {
 546         const char *cp;
 547         unsigned long allot;
 548         size_t l = len;
 549
 550         if (ecb->truncate)
 551                 return ecb->truncate(line, len);
 552         cp = line;
 553         allot = l;
 554         while (0 < l) {
 555                 (void) utf8_width(&cp, &l);
 556                 if (!cp)
 557                         break; /* truncated in the middle? */
 558         }
 559         return allot - l;
 560 }
 561
 562 static void fn_out_consume(void *priv, char *line, unsigned long len)
 563 {
 564         int i;
 565         int color;
 566         struct emit_callback *ecbdata = priv;
 567         const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
 568         const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
 569         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 570
 571         *(ecbdata->found_changesp) = 1;
 572
 573         if (ecbdata->label_path[0]) {
 574                 const char *name_a_tab, *name_b_tab;
 575
 576                 name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
 577                 name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
 578
 579                 fprintf(ecbdata->file, "%s--- %s%s%s\n",
 580                         meta, ecbdata->label_path[0], reset, name_a_tab);
 581                 fprintf(ecbdata->file, "%s+++ %s%s%s\n",
 582                         meta, ecbdata->label_path[1], reset, name_b_tab);
 583                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
 584         }
 585
 586         /* This is not really necessary for now because
 587          * this codepath only deals with two-way diffs.
 588          */
 589         for (i = 0; i < len && line[i] == '@'; i++)
 590                 ;
 591         if (2 <= i && i < len && line[i] == ' ') {
 592                 ecbdata->nparents = i - 1;
 593                 len = sane_truncate_line(ecbdata, line, len);
 594                 emit_line(ecbdata->file,
 595                           diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO),
 596                           reset, line, len);
 597                 if (line[len-1] != '\n')
 598                         putc('\n', ecbdata->file);
 599                 return;
 600         }
 601
 602         if (len < ecbdata->nparents) {
 603                 emit_line(ecbdata->file, reset, reset, line, len);
 604                 return;
 605         }
 606
 607         color = DIFF_PLAIN;
 608         if (ecbdata->diff_words && ecbdata->nparents != 1)
 609                 /* fall back to normal diff */
 610                 free_diff_words_data(ecbdata);
 611         if (ecbdata->diff_words) {
 612                 if (line[0] == '-') {
 613                         diff_words_append(line, len,
 614                                           &ecbdata->diff_words->minus);
 615                         return;
 616                 } else if (line[0] == '+') {
 617                         diff_words_append(line, len,
 618                                           &ecbdata->diff_words->plus);
 619                         return;
 620                 }
 621                 if (ecbdata->diff_words->minus.text.size ||
 622                     ecbdata->diff_words->plus.text.size)
 623                         diff_words_show(ecbdata->diff_words);
 624                 line++;
 625                 len--;
 626                 emit_line(ecbdata->file, plain, reset, line, len);
 627                 return;
 628         }
 629         for (i = 0; i < ecbdata->nparents && len; i++) {
 630                 if (line[i] == '-')
 631                         color = DIFF_FILE_OLD;
 632                 else if (line[i] == '+')
 633                         color = DIFF_FILE_NEW;
 634         }
 635
 636         if (color != DIFF_FILE_NEW) {
 637                 emit_line(ecbdata->file,
 638                           diff_get_color(ecbdata->color_diff, color),
 639                           reset, line, len);
 640                 return;
 641         }
 642         emit_add_line(reset, ecbdata, line, len);
 643 }
 644
 645 static char *pprint_rename(const char *a, const char *b)
 646 {
 647         const char *old = a;
 648         const char *new = b;
 649         struct strbuf name;
 650         int pfx_length, sfx_length;
 651         int len_a = strlen(a);
 652         int len_b = strlen(b);
 653         int a_midlen, b_midlen;
 654         int qlen_a = quote_c_style(a, NULL, NULL, 0);
 655         int qlen_b = quote_c_style(b, NULL, NULL, 0);
 656
 657         strbuf_init(&name, 0);
 658         if (qlen_a || qlen_b) {
 659                 quote_c_style(a, &name, NULL, 0);
 660                 strbuf_addstr(&name, " => ");
 661                 quote_c_style(b, &name, NULL, 0);
 662                 return strbuf_detach(&name, NULL);
 663         }
 664
 665         /* Find common prefix */
 666         pfx_length = 0;
 667         while (*old && *new && *old == *new) {
 668                 if (*old == '/')
 669                         pfx_length = old - a + 1;
 670                 old++;
 671                 new++;
 672         }
 673
 674         /* Find common suffix */
 675         old = a + len_a;
 676         new = b + len_b;
 677         sfx_length = 0;
 678         while (a <= old && b <= new && *old == *new) {
 679                 if (*old == '/')
 680                         sfx_length = len_a - (old - a);
 681                 old--;
 682                 new--;
 683         }
 684
 685         /*
 686          * pfx{mid-a => mid-b}sfx
 687          * {pfx-a => pfx-b}sfx
 688          * pfx{sfx-a => sfx-b}
 689          * name-a => name-b
 690          */
 691         a_midlen = len_a - pfx_length - sfx_length;
 692         b_midlen = len_b - pfx_length - sfx_length;
 693         if (a_midlen < 0)
 694                 a_midlen = 0;
 695         if (b_midlen < 0)
 696                 b_midlen = 0;
 697
 698         strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
 699         if (pfx_length + sfx_length) {
 700                 strbuf_add(&name, a, pfx_length);
 701                 strbuf_addch(&name, '{');
 702         }
 703         strbuf_add(&name, a + pfx_length, a_midlen);
 704         strbuf_addstr(&name, " => ");
 705         strbuf_add(&name, b + pfx_length, b_midlen);
 706         if (pfx_length + sfx_length) {
 707                 strbuf_addch(&name, '}');
 708                 strbuf_add(&name, a + len_a - sfx_length, sfx_length);
 709         }
 710         return strbuf_detach(&name, NULL);
 711 }
 712
 713 struct diffstat_t {
 714         struct xdiff_emit_state xm;
 715
 716         int nr;
 717         int alloc;
 718         struct diffstat_file {
 719                 char *from_name;
 720                 char *name;
 721                 char *print_name;
 722                 unsigned is_unmerged:1;
 723                 unsigned is_binary:1;
 724                 unsigned is_renamed:1;
 725                 unsigned int added, deleted;
 726         } **files;
 727 };
 728
 729 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
 730                                           const char *name_a,
 731                                           const char *name_b)
 732 {
 733         struct diffstat_file *x;
 734         x = xcalloc(sizeof (*x), 1);
 735         if (diffstat->nr == diffstat->alloc) {
 736                 diffstat->alloc = alloc_nr(diffstat->alloc);
 737                 diffstat->files = xrealloc(diffstat->files,
 738                                 diffstat->alloc * sizeof(x));
 739         }
 740         diffstat->files[diffstat->nr++] = x;
 741         if (name_b) {
 742                 x->from_name = xstrdup(name_a);
 743                 x->name = xstrdup(name_b);
 744                 x->is_renamed = 1;
 745         }
 746         else {
 747                 x->from_name = NULL;
 748                 x->name = xstrdup(name_a);
 749         }
 750         return x;
 751 }
 752
 753 static void diffstat_consume(void *priv, char *line, unsigned long len)
 754 {
 755         struct diffstat_t *diffstat = priv;
 756         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
 757
 758         if (line[0] == '+')
 759                 x->added++;
 760         else if (line[0] == '-')
 761                 x->deleted++;
 762 }
 763
 764 const char mime_boundary_leader[] = "------------";
 765
 766 static int scale_linear(int it, int width, int max_change)
 767 {
 768         /*
 769          * make sure that at least one '-' is printed if there were deletions,
 770          * and likewise for '+'.
 771          */
 772         if (max_change < 2)
 773                 return it;
 774         return ((it - 1) * (width - 1) + max_change - 1) / (max_change - 1);
 775 }
 776
 777 static void show_name(FILE *file,
 778                       const char *prefix, const char *name, int len,
 779                       const char *reset, const char *set)
 780 {
 781         fprintf(file, " %s%s%-*s%s |", set, prefix, len, name, reset);
 782 }
 783
 784 static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
 785 {
 786         if (cnt <= 0)
 787                 return;
 788         fprintf(file, "%s", set);
 789         while (cnt--)
 790                 putc(ch, file);
 791         fprintf(file, "%s", reset);
 792 }
 793
 794 static void fill_print_name(struct diffstat_file *file)
 795 {
 796         char *pname;
 797
 798         if (file->print_name)
 799                 return;
 800
 801         if (!file->is_renamed) {
 802                 struct strbuf buf;
 803                 strbuf_init(&buf, 0);
 804                 if (quote_c_style(file->name, &buf, NULL, 0)) {
 805                         pname = strbuf_detach(&buf, NULL);
 806                 } else {
 807                         pname = file->name;
 808                         strbuf_release(&buf);
 809                 }
 810         } else {
 811                 pname = pprint_rename(file->from_name, file->name);
 812         }
 813         file->print_name = pname;
 814 }
 815
 816 static void show_stats(struct diffstat_t* data, struct diff_options *options)
 817 {
 818         int i, len, add, del, total, adds = 0, dels = 0;
 819         int max_change = 0, max_len = 0;
 820         int total_files = data->nr;
 821         int width, name_width;
 822         const char *reset, *set, *add_c, *del_c;
 823
 824         if (data->nr == 0)
 825                 return;
 826
 827         width = options->stat_width ? options->stat_width : 80;
 828         name_width = options->stat_name_width ? options->stat_name_width : 50;
 829
 830         /* Sanity: give at least 5 columns to the graph,
 831          * but leave at least 10 columns for the name.
 832          */
 833         if (width < name_width + 15) {
 834                 if (name_width <= 25)
 835                         width = name_width + 15;
 836                 else
 837                         name_width = width - 15;
 838         }
 839
 840         /* Find the longest filename and max number of changes */
 841         reset = diff_get_color_opt(options, DIFF_RESET);
 842         set   = diff_get_color_opt(options, DIFF_PLAIN);
 843         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
 844         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
 845
 846         for (i = 0; i < data->nr; i++) {
 847                 struct diffstat_file *file = data->files[i];
 848                 int change = file->added + file->deleted;
 849                 fill_print_name(file);
 850                 len = strlen(file->print_name);
 851                 if (max_len < len)
 852                         max_len = len;
 853
 854                 if (file->is_binary || file->is_unmerged)
 855                         continue;
 856                 if (max_change < change)
 857                         max_change = change;
 858         }
 859
 860         /* Compute the width of the graph part;
 861          * 10 is for one blank at the beginning of the line plus
 862          * " | count " between the name and the graph.
 863          *
 864          * From here on, name_width is the width of the name area,
 865          * and width is the width of the graph area.
 866          */
 867         name_width = (name_width < max_len) ? name_width : max_len;
 868         if (width < (name_width + 10) + max_change)
 869                 width = width - (name_width + 10);
 870         else
 871                 width = max_change;
 872
 873         for (i = 0; i < data->nr; i++) {
 874                 const char *prefix = "";
 875                 char *name = data->files[i]->print_name;
 876                 int added = data->files[i]->added;
 877                 int deleted = data->files[i]->deleted;
 878                 int name_len;
 879
 880                 /*
 881                  * "scale" the filename
 882                  */
 883                 len = name_width;
 884                 name_len = strlen(name);
 885                 if (name_width < name_len) {
 886                         char *slash;
 887                         prefix = "...";
 888                         len -= 3;
 889                         name += name_len - len;
 890                         slash = strchr(name, '/');
 891                         if (slash)
 892                                 name = slash;
 893                 }
 894
 895                 if (data->files[i]->is_binary) {
 896                         show_name(options->file, prefix, name, len, reset, set);
 897                         fprintf(options->file, "  Bin ");
 898                         fprintf(options->file, "%s%d%s", del_c, deleted, reset);
 899                         fprintf(options->file, " -> ");
 900                         fprintf(options->file, "%s%d%s", add_c, added, reset);
 901                         fprintf(options->file, " bytes");
 902                         fprintf(options->file, "\n");
 903                         continue;
 904                 }
 905                 else if (data->files[i]->is_unmerged) {
 906                         show_name(options->file, prefix, name, len, reset, set);
 907                         fprintf(options->file, "  Unmerged\n");
 908                         continue;
 909                 }
 910                 else if (!data->files[i]->is_renamed &&
 911                          (added + deleted == 0)) {
 912                         total_files--;
 913                         continue;
 914                 }
 915
 916                 /*
 917                  * scale the add/delete
 918                  */
 919                 add = added;
 920                 del = deleted;
 921                 total = add + del;
 922                 adds += add;
 923                 dels += del;
 924
 925                 if (width <= max_change) {
 926                         add = scale_linear(add, width, max_change);
 927                         del = scale_linear(del, width, max_change);
 928                         total = add + del;
 929                 }
 930                 show_name(options->file, prefix, name, len, reset, set);
 931                 fprintf(options->file, "%5d%s", added + deleted,
 932                                 added + deleted ? " " : "");
 933                 show_graph(options->file, '+', add, add_c, reset);
 934                 show_graph(options->file, '-', del, del_c, reset);
 935                 fprintf(options->file, "\n");
 936         }
 937         fprintf(options->file,
 938                "%s %d files changed, %d insertions(+), %d deletions(-)%s\n",
 939                set, total_files, adds, dels, reset);
 940 }
 941
 942 static void show_shortstats(struct diffstat_t* data, struct diff_options *options)
 943 {
 944         int i, adds = 0, dels = 0, total_files = data->nr;
 945
 946         if (data->nr == 0)
 947                 return;
 948
 949         for (i = 0; i < data->nr; i++) {
 950                 if (!data->files[i]->is_binary &&
 951                     !data->files[i]->is_unmerged) {
 952                         int added = data->files[i]->added;
 953                         int deleted= data->files[i]->deleted;
 954                         if (!data->files[i]->is_renamed &&
 955                             (added + deleted == 0)) {
 956                                 total_files--;
 957                         } else {
 958                                 adds += added;
 959                                 dels += deleted;
 960                         }
 961                 }
 962         }
 963         fprintf(options->file, " %d files changed, %d insertions(+), %d deletions(-)\n",
 964                total_files, adds, dels);
 965 }
 966
 967 static void show_numstat(struct diffstat_t* data, struct diff_options *options)
 968 {
 969         int i;
 970
 971         if (data->nr == 0)
 972                 return;
 973
 974         for (i = 0; i < data->nr; i++) {
 975                 struct diffstat_file *file = data->files[i];
 976
 977                 if (file->is_binary)
 978                         fprintf(options->file, "-\t-\t");
 979                 else
 980                         fprintf(options->file,
 981                                 "%d\t%d\t", file->added, file->deleted);
 982                 if (options->line_termination) {
 983                         fill_print_name(file);
 984                         if (!file->is_renamed)
 985                                 write_name_quoted(file->name, options->file,
 986                                                   options->line_termination);
 987                         else {
 988                                 fputs(file->print_name, options->file);
 989                                 putc(options->line_termination, options->file);
 990                         }
 991                 } else {
 992                         if (file->is_renamed) {
 993                                 putc('\0', options->file);
 994                                 write_name_quoted(file->from_name, options->file, '\0');
 995                         }
 996                         write_name_quoted(file->name, options->file, '\0');
 997                 }
 998         }
 999 }
1000
1001 struct dirstat_file {
1002         const char *name;
1003         unsigned long changed;
1004 };
1005
1006 struct dirstat_dir {
1007         struct dirstat_file *files;
1008         int alloc, nr, percent, cumulative;
1009 };
1010
1011 static long gather_dirstat(FILE *file, struct dirstat_dir *dir, unsigned long changed, const char *base, int baselen)
1012 {
1013         unsigned long this_dir = 0;
1014         unsigned int sources = 0;
1015
1016         while (dir->nr) {
1017                 struct dirstat_file *f = dir->files;
1018                 int namelen = strlen(f->name);
1019                 unsigned long this;
1020                 char *slash;
1021
1022                 if (namelen < baselen)
1023                         break;
1024                 if (memcmp(f->name, base, baselen))
1025                         break;
1026                 slash = strchr(f->name + baselen, '/');
1027                 if (slash) {
1028                         int newbaselen = slash + 1 - f->name;
1029                         this = gather_dirstat(file, dir, changed, f->name, newbaselen);
1030                         sources++;
1031                 } else {
1032                         this = f->changed;
1033                         dir->files++;
1034                         dir->nr--;
1035                         sources += 2;
1036                 }
1037                 this_dir += this;
1038         }
1039
1040         /*
1041          * We don't report dirstat's for
1042          *  - the top level
1043          *  - or cases where everything came from a single directory
1044          *    under this directory (sources == 1).
1045          */
1046         if (baselen && sources != 1) {
1047                 int permille = this_dir * 1000 / changed;
1048                 if (permille) {
1049                         int percent = permille / 10;
1050                         if (percent >= dir->percent) {
1051                                 fprintf(file, "%4d.%01d%% %.*s\n", percent, permille % 10, baselen, base);
1052                                 if (!dir->cumulative)
1053                                         return 0;
1054                         }
1055                 }
1056         }
1057         return this_dir;
1058 }
1059
1060 static void show_dirstat(struct diff_options *options)
1061 {
1062         int i;
1063         unsigned long changed;
1064         struct dirstat_dir dir;
1065         struct diff_queue_struct *q = &diff_queued_diff;
1066
1067         dir.files = NULL;
1068         dir.alloc = 0;
1069         dir.nr = 0;
1070         dir.percent = options->dirstat_percent;
1071         dir.cumulative = options->output_format & DIFF_FORMAT_CUMULATIVE;
1072
1073         changed = 0;
1074         for (i = 0; i < q->nr; i++) {
1075                 struct diff_filepair *p = q->queue[i];
1076                 const char *name;
1077                 unsigned long copied, added, damage;
1078
1079                 name = p->one->path ? p->one->path : p->two->path;
1080
1081                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1082                         diff_populate_filespec(p->one, 0);
1083                         diff_populate_filespec(p->two, 0);
1084                         diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1085                                                &copied, &added);
1086                         diff_free_filespec_data(p->one);
1087                         diff_free_filespec_data(p->two);
1088                 } else if (DIFF_FILE_VALID(p->one)) {
1089                         diff_populate_filespec(p->one, 1);
1090                         copied = added = 0;
1091                         diff_free_filespec_data(p->one);
1092                 } else if (DIFF_FILE_VALID(p->two)) {
1093                         diff_populate_filespec(p->two, 1);
1094                         copied = 0;
1095                         added = p->two->size;
1096                         diff_free_filespec_data(p->two);
1097                 } else
1098                         continue;
1099
1100                 /*
1101                  * Original minus copied is the removed material,
1102                  * added is the new material.  They are both damages
1103                  * made to the preimage.
1104                  */
1105                 damage = (p->one->size - copied) + added;
1106
1107                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1108                 dir.files[dir.nr].name = name;
1109                 dir.files[dir.nr].changed = damage;
1110                 changed += damage;
1111                 dir.nr++;
1112         }
1113
1114         /* This can happen even with many files, if everything was renames */
1115         if (!changed)
1116                 return;
1117
1118         /* Show all directories with more than x% of the changes */
1119         gather_dirstat(options->file, &dir, changed, "", 0);
1120 }
1121
1122 static void free_diffstat_info(struct diffstat_t *diffstat)
1123 {
1124         int i;
1125         for (i = 0; i < diffstat->nr; i++) {
1126                 struct diffstat_file *f = diffstat->files[i];
1127                 if (f->name != f->print_name)
1128                         free(f->print_name);
1129                 free(f->name);
1130                 free(f->from_name);
1131                 free(f);
1132         }
1133         free(diffstat->files);
1134 }
1135
1136 struct checkdiff_t {
1137         struct xdiff_emit_state xm;
1138         const char *filename;
1139         int lineno, color_diff;
1140         unsigned ws_rule;
1141         unsigned status;
1142         FILE *file;
1143 };
1144
1145 static void checkdiff_consume(void *priv, char *line, unsigned long len)
1146 {
1147         struct checkdiff_t *data = priv;
1148         const char *ws = diff_get_color(data->color_diff, DIFF_WHITESPACE);
1149         const char *reset = diff_get_color(data->color_diff, DIFF_RESET);
1150         const char *set = diff_get_color(data->color_diff, DIFF_FILE_NEW);
1151         char *err;
1152
1153         if (line[0] == '+') {
1154                 data->lineno++;
1155                 data->status = check_and_emit_line(line + 1, len - 1,
1156                     data->ws_rule, NULL, NULL, NULL, NULL);
1157                 if (!data->status)
1158                         return;
1159                 err = whitespace_error_string(data->status);
1160                 fprintf(data->file, "%s:%d: %s.\n", data->filename, data->lineno, err);
1161                 free(err);
1162                 emit_line(data->file, set, reset, line, 1);
1163                 (void)check_and_emit_line(line + 1, len - 1, data->ws_rule,
1164                     data->file, set, reset, ws);
1165         } else if (line[0] == ' ')
1166                 data->lineno++;
1167         else if (line[0] == '@') {
1168                 char *plus = strchr(line, '+');
1169                 if (plus)
1170                         data->lineno = strtol(plus, NULL, 10) - 1;
1171                 else
1172                         die("invalid diff");
1173         }
1174 }
1175
1176 static unsigned char *deflate_it(char *data,
1177                                  unsigned long size,
1178                                  unsigned long *result_size)
1179 {
1180         int bound;
1181         unsigned char *deflated;
1182         z_stream stream;
1183
1184         memset(&stream, 0, sizeof(stream));
1185         deflateInit(&stream, zlib_compression_level);
1186         bound = deflateBound(&stream, size);
1187         deflated = xmalloc(bound);
1188         stream.next_out = deflated;
1189         stream.avail_out = bound;
1190
1191         stream.next_in = (unsigned char *)data;
1192         stream.avail_in = size;
1193         while (deflate(&stream, Z_FINISH) == Z_OK)
1194                 ; /* nothing */
1195         deflateEnd(&stream);
1196         *result_size = stream.total_out;
1197         return deflated;
1198 }
1199
1200 static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two)
1201 {
1202         void *cp;
1203         void *delta;
1204         void *deflated;
1205         void *data;
1206         unsigned long orig_size;
1207         unsigned long delta_size;
1208         unsigned long deflate_size;
1209         unsigned long data_size;
1210
1211         /* We could do deflated delta, or we could do just deflated two,
1212          * whichever is smaller.
1213          */
1214         delta = NULL;
1215         deflated = deflate_it(two->ptr, two->size, &deflate_size);
1216         if (one->size && two->size) {
1217                 delta = diff_delta(one->ptr, one->size,
1218                                    two->ptr, two->size,
1219                                    &delta_size, deflate_size);
1220                 if (delta) {
1221                         void *to_free = delta;
1222                         orig_size = delta_size;
1223                         delta = deflate_it(delta, delta_size, &delta_size);
1224                         free(to_free);
1225                 }
1226         }
1227
1228         if (delta && delta_size < deflate_size) {
1229                 fprintf(file, "delta %lu\n", orig_size);
1230                 free(deflated);
1231                 data = delta;
1232                 data_size = delta_size;
1233         }
1234         else {
1235                 fprintf(file, "literal %lu\n", two->size);
1236                 free(delta);
1237                 data = deflated;
1238                 data_size = deflate_size;
1239         }
1240
1241         /* emit data encoded in base85 */
1242         cp = data;
1243         while (data_size) {
1244                 int bytes = (52 < data_size) ? 52 : data_size;
1245                 char line[70];
1246                 data_size -= bytes;
1247                 if (bytes <= 26)
1248                         line[0] = bytes + 'A' - 1;
1249                 else
1250                         line[0] = bytes - 26 + 'a' - 1;
1251                 encode_85(line + 1, cp, bytes);
1252                 cp = (char *) cp + bytes;
1253                 fputs(line, file);
1254                 fputc('\n', file);
1255         }
1256         fprintf(file, "\n");
1257         free(data);
1258 }
1259
1260 static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two)
1261 {
1262         fprintf(file, "GIT binary patch\n");
1263         emit_binary_diff_body(file, one, two);
1264         emit_binary_diff_body(file, two, one);
1265 }
1266
1267 static void setup_diff_attr_check(struct git_attr_check *check)
1268 {
1269         static struct git_attr *attr_diff;
1270
1271         if (!attr_diff) {
1272                 attr_diff = git_attr("diff", 4);
1273         }
1274         check[0].attr = attr_diff;
1275 }
1276
1277 static void diff_filespec_check_attr(struct diff_filespec *one)
1278 {
1279         struct git_attr_check attr_diff_check;
1280         int check_from_data = 0;
1281
1282         if (one->checked_attr)
1283                 return;
1284
1285         setup_diff_attr_check(&attr_diff_check);
1286         one->is_binary = 0;
1287         one->funcname_pattern_ident = NULL;
1288
1289         if (!git_checkattr(one->path, 1, &attr_diff_check)) {
1290                 const char *value;
1291
1292                 /* binaryness */
1293                 value = attr_diff_check.value;
1294                 if (ATTR_TRUE(value))
1295                         ;
1296                 else if (ATTR_FALSE(value))
1297                         one->is_binary = 1;
1298                 else
1299                         check_from_data = 1;
1300
1301                 /* funcname pattern ident */
1302                 if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
1303                         ;
1304                 else
1305                         one->funcname_pattern_ident = value;
1306         }
1307
1308         if (check_from_data) {
1309                 if (!one->data && DIFF_FILE_VALID(one))
1310                         diff_populate_filespec(one, 0);
1311
1312                 if (one->data)
1313                         one->is_binary = buffer_is_binary(one->data, one->size);
1314         }
1315 }
1316
1317 int diff_filespec_is_binary(struct diff_filespec *one)
1318 {
1319         diff_filespec_check_attr(one);
1320         return one->is_binary;
1321 }
1322
1323 static const char *funcname_pattern(const char *ident)
1324 {
1325         struct funcname_pattern *pp;
1326
1327         for (pp = funcname_pattern_list; pp; pp = pp->next)
1328                 if (!strcmp(ident, pp->name))
1329                         return pp->pattern;
1330         return NULL;
1331 }
1332
1333 static struct builtin_funcname_pattern {
1334         const char *name;
1335         const char *pattern;
1336 } builtin_funcname_pattern[] = {
1337         { "java", "!^[  ]*\\(catch\\|do\\|for\\|if\\|instanceof\\|"
1338                         "new\\|return\\|switch\\|throw\\|while\\)\n"
1339                         "^[     ]*\\(\\([       ]*"
1340                         "[A-Za-z_][A-Za-z_0-9]*\\)\\{2,\\}"
1341                         "[      ]*([^;]*\\)$" },
1342         { "tex", "^\\(\\\\\\(sub\\)*section{.*\\)$" },
1343 };
1344
1345 static const char *diff_funcname_pattern(struct diff_filespec *one)
1346 {
1347         const char *ident, *pattern;
1348         int i;
1349
1350         diff_filespec_check_attr(one);
1351         ident = one->funcname_pattern_ident;
1352
1353         if (!ident)
1354                 /*
1355                  * If the config file has "funcname.default" defined, that
1356                  * regexp is used; otherwise NULL is returned and xemit uses
1357                  * the built-in default.
1358                  */
1359                 return funcname_pattern("default");
1360
1361         /* Look up custom "funcname.$ident" regexp from config. */
1362         pattern = funcname_pattern(ident);
1363         if (pattern)
1364                 return pattern;
1365
1366         /*
1367          * And define built-in fallback patterns here.  Note that
1368          * these can be overridden by the user's config settings.
1369          */
1370         for (i = 0; i < ARRAY_SIZE(builtin_funcname_pattern); i++)
1371                 if (!strcmp(ident, builtin_funcname_pattern[i].name))
1372                         return builtin_funcname_pattern[i].pattern;
1373
1374         return NULL;
1375 }
1376
1377 static void builtin_diff(const char *name_a,
1378                          const char *name_b,
1379                          struct diff_filespec *one,
1380                          struct diff_filespec *two,
1381                          const char *xfrm_msg,
1382                          struct diff_options *o,
1383                          int complete_rewrite)
1384 {
1385         mmfile_t mf1, mf2;
1386         const char *lbl[2];
1387         char *a_one, *b_two;
1388         const char *set = diff_get_color_opt(o, DIFF_METAINFO);
1389         const char *reset = diff_get_color_opt(o, DIFF_RESET);
1390
1391         a_one = quote_two(o->a_prefix, name_a + (*name_a == '/'));
1392         b_two = quote_two(o->b_prefix, name_b + (*name_b == '/'));
1393         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
1394         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
1395         fprintf(o->file, "%sdiff --git %s %s%s\n", set, a_one, b_two, reset);
1396         if (lbl[0][0] == '/') {
1397                 /* /dev/null */
1398                 fprintf(o->file, "%snew file mode %06o%s\n", set, two->mode, reset);
1399                 if (xfrm_msg && xfrm_msg[0])
1400                         fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
1401         }
1402         else if (lbl[1][0] == '/') {
1403                 fprintf(o->file, "%sdeleted file mode %06o%s\n", set, one->mode, reset);
1404                 if (xfrm_msg && xfrm_msg[0])
1405                         fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
1406         }
1407         else {
1408                 if (one->mode != two->mode) {
1409                         fprintf(o->file, "%sold mode %06o%s\n", set, one->mode, reset);
1410                         fprintf(o->file, "%snew mode %06o%s\n", set, two->mode, reset);
1411                 }
1412                 if (xfrm_msg && xfrm_msg[0])
1413                         fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
1414                 /*
1415                  * we do not run diff between different kind
1416                  * of objects.
1417                  */
1418                 if ((one->mode ^ two->mode) & S_IFMT)
1419                         goto free_ab_and_return;
1420                 if (complete_rewrite) {
1421                         emit_rewrite_diff(name_a, name_b, one, two, o);
1422                         o->found_changes = 1;
1423                         goto free_ab_and_return;
1424                 }
1425         }
1426
1427         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1428                 die("unable to read files to diff");
1429
1430         if (!DIFF_OPT_TST(o, TEXT) &&
1431             (diff_filespec_is_binary(one) || diff_filespec_is_binary(two))) {
1432                 /* Quite common confusing case */
1433                 if (mf1.size == mf2.size &&
1434                     !memcmp(mf1.ptr, mf2.ptr, mf1.size))
1435                         goto free_ab_and_return;
1436                 if (DIFF_OPT_TST(o, BINARY))
1437                         emit_binary_diff(o->file, &mf1, &mf2);
1438                 else
1439                         fprintf(o->file, "Binary files %s and %s differ\n",
1440                                 lbl[0], lbl[1]);
1441                 o->found_changes = 1;
1442         }
1443         else {
1444                 /* Crazy xdl interfaces.. */
1445                 const char *diffopts = getenv("GIT_DIFF_OPTS");
1446                 xpparam_t xpp;
1447                 xdemitconf_t xecfg;
1448                 xdemitcb_t ecb;
1449                 struct emit_callback ecbdata;
1450                 const char *funcname_pattern;
1451
1452                 funcname_pattern = diff_funcname_pattern(one);
1453                 if (!funcname_pattern)
1454                         funcname_pattern = diff_funcname_pattern(two);
1455
1456                 memset(&xecfg, 0, sizeof(xecfg));
1457                 memset(&ecbdata, 0, sizeof(ecbdata));
1458                 ecbdata.label_path = lbl;
1459                 ecbdata.color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
1460                 ecbdata.found_changesp = &o->found_changes;
1461                 ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
1462                 ecbdata.file = o->file;
1463                 xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
1464                 xecfg.ctxlen = o->context;
1465                 xecfg.flags = XDL_EMIT_FUNCNAMES;
1466                 if (funcname_pattern)
1467                         xdiff_set_find_func(&xecfg, funcname_pattern);
1468                 if (!diffopts)
1469                         ;
1470                 else if (!prefixcmp(diffopts, "--unified="))
1471                         xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
1472                 else if (!prefixcmp(diffopts, "-u"))
1473                         xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
1474                 ecb.outf = xdiff_outf;
1475                 ecb.priv = &ecbdata;
1476                 ecbdata.xm.consume = fn_out_consume;
1477                 if (DIFF_OPT_TST(o, COLOR_DIFF_WORDS)) {
1478                         ecbdata.diff_words =
1479                                 xcalloc(1, sizeof(struct diff_words_data));
1480                         ecbdata.diff_words->file = o->file;
1481                 }
1482                 xdi_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
1483                 if (DIFF_OPT_TST(o, COLOR_DIFF_WORDS))
1484                         free_diff_words_data(&ecbdata);
1485         }
1486
1487  free_ab_and_return:
1488         diff_free_filespec_data(one);
1489         diff_free_filespec_data(two);
1490         free(a_one);
1491         free(b_two);
1492         return;
1493 }
1494
1495 static void builtin_diffstat(const char *name_a, const char *name_b,
1496                              struct diff_filespec *one,
1497                              struct diff_filespec *two,
1498                              struct diffstat_t *diffstat,
1499                              struct diff_options *o,
1500                              int complete_rewrite)
1501 {
1502         mmfile_t mf1, mf2;
1503         struct diffstat_file *data;
1504
1505         data = diffstat_add(diffstat, name_a, name_b);
1506
1507         if (!one || !two) {
1508                 data->is_unmerged = 1;
1509                 return;
1510         }
1511         if (complete_rewrite) {
1512                 diff_populate_filespec(one, 0);
1513                 diff_populate_filespec(two, 0);
1514                 data->deleted = count_lines(one->data, one->size);
1515                 data->added = count_lines(two->data, two->size);
1516                 goto free_and_return;
1517         }
1518         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1519                 die("unable to read files to diff");
1520
1521         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
1522                 data->is_binary = 1;
1523                 data->added = mf2.size;
1524                 data->deleted = mf1.size;
1525         } else {
1526                 /* Crazy xdl interfaces.. */
1527                 xpparam_t xpp;
1528                 xdemitconf_t xecfg;
1529                 xdemitcb_t ecb;
1530
1531                 memset(&xecfg, 0, sizeof(xecfg));
1532                 xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
1533                 ecb.outf = xdiff_outf;
1534                 ecb.priv = diffstat;
1535                 xdi_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
1536         }
1537
1538  free_and_return:
1539         diff_free_filespec_data(one);
1540         diff_free_filespec_data(two);
1541 }
1542
1543 static void builtin_checkdiff(const char *name_a, const char *name_b,
1544                               const char *attr_path,
1545                              struct diff_filespec *one,
1546                              struct diff_filespec *two, struct diff_options *o)
1547 {
1548         mmfile_t mf1, mf2;
1549         struct checkdiff_t data;
1550
1551         if (!two)
1552                 return;
1553
1554         memset(&data, 0, sizeof(data));
1555         data.xm.consume = checkdiff_consume;
1556         data.filename = name_b ? name_b : name_a;
1557         data.lineno = 0;
1558         data.color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
1559         data.ws_rule = whitespace_rule(attr_path);
1560         data.file = o->file;
1561
1562         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1563                 die("unable to read files to diff");
1564
1565         if (diff_filespec_is_binary(two))
1566                 goto free_and_return;
1567         else {
1568                 /* Crazy xdl interfaces.. */
1569                 xpparam_t xpp;
1570                 xdemitconf_t xecfg;
1571                 xdemitcb_t ecb;
1572
1573                 memset(&xecfg, 0, sizeof(xecfg));
1574                 xpp.flags = XDF_NEED_MINIMAL;
1575                 ecb.outf = xdiff_outf;
1576                 ecb.priv = &data;
1577                 xdi_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
1578         }
1579  free_and_return:
1580         diff_free_filespec_data(one);
1581         diff_free_filespec_data(two);
1582         if (data.status)
1583                 DIFF_OPT_SET(o, CHECK_FAILED);
1584 }
1585
1586 struct diff_filespec *alloc_filespec(const char *path)
1587 {
1588         int namelen = strlen(path);
1589         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
1590
1591         memset(spec, 0, sizeof(*spec));
1592         spec->path = (char *)(spec + 1);
1593         memcpy(spec->path, path, namelen+1);
1594         spec->count = 1;
1595         return spec;
1596 }
1597
1598 void free_filespec(struct diff_filespec *spec)
1599 {
1600         if (!--spec->count) {
1601                 diff_free_filespec_data(spec);
1602                 free(spec);
1603         }
1604 }
1605
1606 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
1607                    unsigned short mode)
1608 {
1609         if (mode) {
1610                 spec->mode = canon_mode(mode);
1611                 hashcpy(spec->sha1, sha1);
1612                 spec->sha1_valid = !is_null_sha1(sha1);
1613         }
1614 }
1615
1616 /*
1617  * Given a name and sha1 pair, if the index tells us the file in
1618  * the work tree has that object contents, return true, so that
1619  * prepare_temp_file() does not have to inflate and extract.
1620  */
1621 static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
1622 {
1623         struct cache_entry *ce;
1624         struct stat st;
1625         int pos, len;
1626
1627         /* We do not read the cache ourselves here, because the
1628          * benchmark with my previous version that always reads cache
1629          * shows that it makes things worse for diff-tree comparing
1630          * two linux-2.6 kernel trees in an already checked out work
1631          * tree.  This is because most diff-tree comparisons deal with
1632          * only a small number of files, while reading the cache is
1633          * expensive for a large project, and its cost outweighs the
1634          * savings we get by not inflating the object to a temporary
1635          * file.  Practically, this code only helps when we are used
1636          * by diff-cache --cached, which does read the cache before
1637          * calling us.
1638          */
1639         if (!active_cache)
1640                 return 0;
1641
1642         /* We want to avoid the working directory if our caller
1643          * doesn't need the data in a normal file, this system
1644          * is rather slow with its stat/open/mmap/close syscalls,
1645          * and the object is contained in a pack file.  The pack
1646          * is probably already open and will be faster to obtain
1647          * the data through than the working directory.  Loose
1648          * objects however would tend to be slower as they need
1649          * to be individually opened and inflated.
1650          */
1651         if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1, NULL))
1652                 return 0;
1653
1654         len = strlen(name);
1655         pos = cache_name_pos(name, len);
1656         if (pos < 0)
1657                 return 0;
1658         ce = active_cache[pos];
1659
1660         /*
1661          * This is not the sha1 we are looking for, or
1662          * unreusable because it is not a regular file.
1663          */
1664         if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
1665                 return 0;
1666
1667         /*
1668          * If ce matches the file in the work tree, we can reuse it.
1669          */
1670         if (ce_uptodate(ce) ||
1671             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
1672                 return 1;
1673
1674         return 0;
1675 }
1676
1677 static int populate_from_stdin(struct diff_filespec *s)
1678 {
1679         struct strbuf buf;
1680         size_t size = 0;
1681
1682         strbuf_init(&buf, 0);
1683         if (strbuf_read(&buf, 0, 0) < 0)
1684                 return error("error while reading from stdin %s",
1685                                      strerror(errno));
1686
1687         s->should_munmap = 0;
1688         s->data = strbuf_detach(&buf, &size);
1689         s->size = size;
1690         s->should_free = 1;
1691         return 0;
1692 }
1693
1694 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
1695 {
1696         int len;
1697         char *data = xmalloc(100);
1698         len = snprintf(data, 100,
1699                 "Subproject commit %s\n", sha1_to_hex(s->sha1));
1700         s->data = data;
1701         s->size = len;
1702         s->should_free = 1;
1703         if (size_only) {
1704                 s->data = NULL;
1705                 free(data);
1706         }
1707         return 0;
1708 }
1709
1710 /*
1711  * While doing rename detection and pickaxe operation, we may need to
1712  * grab the data for the blob (or file) for our own in-core comparison.
1713  * diff_filespec has data and size fields for this purpose.
1714  */
1715 int diff_populate_filespec(struct diff_filespec *s, int size_only)
1716 {
1717         int err = 0;
1718         if (!DIFF_FILE_VALID(s))
1719                 die("internal error: asking to populate invalid file.");
1720         if (S_ISDIR(s->mode))
1721                 return -1;
1722
1723         if (s->data)
1724                 return 0;
1725
1726         if (size_only && 0 < s->size)
1727                 return 0;
1728
1729         if (S_ISGITLINK(s->mode))
1730                 return diff_populate_gitlink(s, size_only);
1731
1732         if (!s->sha1_valid ||
1733             reuse_worktree_file(s->path, s->sha1, 0)) {
1734                 struct strbuf buf;
1735                 struct stat st;
1736                 int fd;
1737
1738                 if (!strcmp(s->path, "-"))
1739                         return populate_from_stdin(s);
1740
1741                 if (lstat(s->path, &st) < 0) {
1742                         if (errno == ENOENT) {
1743                         err_empty:
1744                                 err = -1;
1745                         empty:
1746                                 s->data = (char *)"";
1747                                 s->size = 0;
1748                                 return err;
1749                         }
1750                 }
1751                 s->size = xsize_t(st.st_size);
1752                 if (!s->size)
1753                         goto empty;
1754                 if (size_only)
1755                         return 0;
1756                 if (S_ISLNK(st.st_mode)) {
1757                         int ret;
1758                         s->data = xmalloc(s->size);
1759                         s->should_free = 1;
1760                         ret = readlink(s->path, s->data, s->size);
1761                         if (ret < 0) {
1762                                 free(s->data);
1763                                 goto err_empty;
1764                         }
1765                         return 0;
1766                 }
1767                 fd = open(s->path, O_RDONLY);
1768                 if (fd < 0)
1769                         goto err_empty;
1770                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
1771                 close(fd);
1772                 s->should_munmap = 1;
1773
1774                 /*
1775                  * Convert from working tree format to canonical git format
1776                  */
1777                 strbuf_init(&buf, 0);
1778                 if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
1779                         size_t size = 0;
1780                         munmap(s->data, s->size);
1781                         s->should_munmap = 0;
1782                         s->data = strbuf_detach(&buf, &size);
1783                         s->size = size;
1784                         s->should_free = 1;
1785                 }
1786         }
1787         else {
1788                 enum object_type type;
1789                 if (size_only)
1790                         type = sha1_object_info(s->sha1, &s->size);
1791                 else {
1792                         s->data = read_sha1_file(s->sha1, &type, &s->size);
1793                         s->should_free = 1;
1794                 }
1795         }
1796         return 0;
1797 }
1798
1799 void diff_free_filespec_blob(struct diff_filespec *s)
1800 {
1801         if (s->should_free)
1802                 free(s->data);
1803         else if (s->should_munmap)
1804                 munmap(s->data, s->size);
1805
1806         if (s->should_free || s->should_munmap) {
1807                 s->should_free = s->should_munmap = 0;
1808                 s->data = NULL;
1809         }
1810 }
1811
1812 void diff_free_filespec_data(struct diff_filespec *s)
1813 {
1814         diff_free_filespec_blob(s);
1815         free(s->cnt_data);
1816         s->cnt_data = NULL;
1817 }
1818
1819 static void prep_temp_blob(struct diff_tempfile *temp,
1820                            void *blob,
1821                            unsigned long size,
1822                            const unsigned char *sha1,
1823                            int mode)
1824 {
1825         int fd;
1826
1827         fd = git_mkstemp(temp->tmp_path, PATH_MAX, ".diff_XXXXXX");
1828         if (fd < 0)
1829                 die("unable to create temp-file: %s", strerror(errno));
1830         if (write_in_full(fd, blob, size) != size)
1831                 die("unable to write temp-file");
1832         close(fd);
1833         temp->name = temp->tmp_path;
1834         strcpy(temp->hex, sha1_to_hex(sha1));
1835         temp->hex[40] = 0;
1836         sprintf(temp->mode, "%06o", mode);
1837 }
1838
1839 static void prepare_temp_file(const char *name,
1840                               struct diff_tempfile *temp,
1841                               struct diff_filespec *one)
1842 {
1843         if (!DIFF_FILE_VALID(one)) {
1844         not_a_valid_file:
1845                 /* A '-' entry produces this for file-2, and
1846                  * a '+' entry produces this for file-1.
1847                  */
1848                 temp->name = "/dev/null";
1849                 strcpy(temp->hex, ".");
1850                 strcpy(temp->mode, ".");
1851                 return;
1852         }
1853
1854         if (!one->sha1_valid ||
1855             reuse_worktree_file(name, one->sha1, 1)) {
1856                 struct stat st;
1857                 if (lstat(name, &st) < 0) {
1858                         if (errno == ENOENT)
1859                                 goto not_a_valid_file;
1860                         die("stat(%s): %s", name, strerror(errno));
1861                 }
1862                 if (S_ISLNK(st.st_mode)) {
1863                         int ret;
1864                         char buf[PATH_MAX + 1]; /* ought to be SYMLINK_MAX */
1865                         size_t sz = xsize_t(st.st_size);
1866                         if (sizeof(buf) <= st.st_size)
1867                                 die("symlink too long: %s", name);
1868                         ret = readlink(name, buf, sz);
1869                         if (ret < 0)
1870                                 die("readlink(%s)", name);
1871                         prep_temp_blob(temp, buf, sz,
1872                                        (one->sha1_valid ?
1873                                         one->sha1 : null_sha1),
1874                                        (one->sha1_valid ?
1875                                         one->mode : S_IFLNK));
1876                 }
1877                 else {
1878                         /* we can borrow from the file in the work tree */
1879                         temp->name = name;
1880                         if (!one->sha1_valid)
1881                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
1882                         else
1883                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
1884                         /* Even though we may sometimes borrow the
1885                          * contents from the work tree, we always want
1886                          * one->mode.  mode is trustworthy even when
1887                          * !(one->sha1_valid), as long as
1888                          * DIFF_FILE_VALID(one).
1889                          */
1890                         sprintf(temp->mode, "%06o", one->mode);
1891                 }
1892                 return;
1893         }
1894         else {
1895                 if (diff_populate_filespec(one, 0))
1896                         die("cannot read data blob for %s", one->path);
1897                 prep_temp_blob(temp, one->data, one->size,
1898                                one->sha1, one->mode);
1899         }
1900 }
1901
1902 static void remove_tempfile(void)
1903 {
1904         int i;
1905
1906         for (i = 0; i < 2; i++)
1907                 if (diff_temp[i].name == diff_temp[i].tmp_path) {
1908                         unlink(diff_temp[i].name);
1909                         diff_temp[i].name = NULL;
1910                 }
1911 }
1912
1913 static void remove_tempfile_on_signal(int signo)
1914 {
1915         remove_tempfile();
1916         signal(SIGINT, SIG_DFL);
1917         raise(signo);
1918 }
1919
1920 /* An external diff command takes:
1921  *
1922  * diff-cmd name infile1 infile1-sha1 infile1-mode \
1923  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
1924  *
1925  */
1926 static void run_external_diff(const char *pgm,
1927                               const char *name,
1928                               const char *other,
1929                               struct diff_filespec *one,
1930                               struct diff_filespec *two,
1931                               const char *xfrm_msg,
1932                               int complete_rewrite)
1933 {
1934         const char *spawn_arg[10];
1935         struct diff_tempfile *temp = diff_temp;
1936         int retval;
1937         static int atexit_asked = 0;
1938         const char *othername;
1939         const char **arg = &spawn_arg[0];
1940
1941         othername = (other? other : name);
1942         if (one && two) {
1943                 prepare_temp_file(name, &temp[0], one);
1944                 prepare_temp_file(othername, &temp[1], two);
1945                 if (! atexit_asked &&
1946                     (temp[0].name == temp[0].tmp_path ||
1947                      temp[1].name == temp[1].tmp_path)) {
1948                         atexit_asked = 1;
1949                         atexit(remove_tempfile);
1950                 }
1951                 signal(SIGINT, remove_tempfile_on_signal);
1952         }
1953
1954         if (one && two) {
1955                 *arg++ = pgm;
1956                 *arg++ = name;
1957                 *arg++ = temp[0].name;
1958                 *arg++ = temp[0].hex;
1959                 *arg++ = temp[0].mode;
1960                 *arg++ = temp[1].name;
1961                 *arg++ = temp[1].hex;
1962                 *arg++ = temp[1].mode;
1963                 if (other) {
1964                         *arg++ = other;
1965                         *arg++ = xfrm_msg;
1966                 }
1967         } else {
1968                 *arg++ = pgm;
1969                 *arg++ = name;
1970         }
1971         *arg = NULL;
1972         fflush(NULL);
1973         retval = run_command_v_opt(spawn_arg, 0);
1974         remove_tempfile();
1975         if (retval) {
1976                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
1977                 exit(1);
1978         }
1979 }
1980
1981 static const char *external_diff_attr(const char *name)
1982 {
1983         struct git_attr_check attr_diff_check;
1984
1985         if (!name)
1986                 return NULL;
1987
1988         setup_diff_attr_check(&attr_diff_check);
1989         if (!git_checkattr(name, 1, &attr_diff_check)) {
1990                 const char *value = attr_diff_check.value;
1991                 if (!ATTR_TRUE(value) &&
1992                     !ATTR_FALSE(value) &&
1993                     !ATTR_UNSET(value)) {
1994                         struct ll_diff_driver *drv;
1995
1996                         for (drv = user_diff; drv; drv = drv->next)
1997                                 if (!strcmp(drv->name, value))
1998                                         return drv->cmd;
1999                 }
2000         }
2001         return NULL;
2002 }
2003
2004 static void run_diff_cmd(const char *pgm,
2005                          const char *name,
2006                          const char *other,
2007                          const char *attr_path,
2008                          struct diff_filespec *one,
2009                          struct diff_filespec *two,
2010                          const char *xfrm_msg,
2011                          struct diff_options *o,
2012                          int complete_rewrite)
2013 {
2014         if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
2015                 pgm = NULL;
2016         else {
2017                 const char *cmd = external_diff_attr(attr_path);
2018                 if (cmd)
2019                         pgm = cmd;
2020         }
2021
2022         if (pgm) {
2023                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
2024                                   complete_rewrite);
2025                 return;
2026         }
2027         if (one && two)
2028                 builtin_diff(name, other ? other : name,
2029                              one, two, xfrm_msg, o, complete_rewrite);
2030         else
2031                 fprintf(o->file, "* Unmerged path %s\n", name);
2032 }
2033
2034 static void diff_fill_sha1_info(struct diff_filespec *one)
2035 {
2036         if (DIFF_FILE_VALID(one)) {
2037                 if (!one->sha1_valid) {
2038                         struct stat st;
2039                         if (!strcmp(one->path, "-")) {
2040                                 hashcpy(one->sha1, null_sha1);
2041                                 return;
2042                         }
2043                         if (lstat(one->path, &st) < 0)
2044                                 die("stat %s", one->path);
2045                         if (index_path(one->sha1, one->path, &st, 0))
2046                                 die("cannot hash %s\n", one->path);
2047                 }
2048         }
2049         else
2050                 hashclr(one->sha1);
2051 }
2052
2053 static int similarity_index(struct diff_filepair *p)
2054 {
2055         return p->score * 100 / MAX_SCORE;
2056 }
2057
2058 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
2059 {
2060         /* Strip the prefix but do not molest /dev/null and absolute paths */
2061         if (*namep && **namep != '/')
2062                 *namep += prefix_length;
2063         if (*otherp && **otherp != '/')
2064                 *otherp += prefix_length;
2065 }
2066
2067 static void run_diff(struct diff_filepair *p, struct diff_options *o)
2068 {
2069         const char *pgm = external_diff();
2070         struct strbuf msg;
2071         char *xfrm_msg;
2072         struct diff_filespec *one = p->one;
2073         struct diff_filespec *two = p->two;
2074         const char *name;
2075         const char *other;
2076         const char *attr_path;
2077         int complete_rewrite = 0;
2078
2079         name  = p->one->path;
2080         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2081         attr_path = name;
2082         if (o->prefix_length)
2083                 strip_prefix(o->prefix_length, &name, &other);
2084
2085         if (DIFF_PAIR_UNMERGED(p)) {
2086                 run_diff_cmd(pgm, name, NULL, attr_path,
2087                              NULL, NULL, NULL, o, 0);
2088                 return;
2089         }
2090
2091         diff_fill_sha1_info(one);
2092         diff_fill_sha1_info(two);
2093
2094         strbuf_init(&msg, PATH_MAX * 2 + 300);
2095         switch (p->status) {
2096         case DIFF_STATUS_COPIED:
2097                 strbuf_addf(&msg, "similarity index %d%%", similarity_index(p));
2098                 strbuf_addstr(&msg, "\ncopy from ");
2099                 quote_c_style(name, &msg, NULL, 0);
2100                 strbuf_addstr(&msg, "\ncopy to ");
2101                 quote_c_style(other, &msg, NULL, 0);
2102                 strbuf_addch(&msg, '\n');
2103                 break;
2104         case DIFF_STATUS_RENAMED:
2105                 strbuf_addf(&msg, "similarity index %d%%", similarity_index(p));
2106                 strbuf_addstr(&msg, "\nrename from ");
2107                 quote_c_style(name, &msg, NULL, 0);
2108                 strbuf_addstr(&msg, "\nrename to ");
2109                 quote_c_style(other, &msg, NULL, 0);
2110                 strbuf_addch(&msg, '\n');
2111                 break;
2112         case DIFF_STATUS_MODIFIED:
2113                 if (p->score) {
2114                         strbuf_addf(&msg, "dissimilarity index %d%%\n",
2115                                         similarity_index(p));
2116                         complete_rewrite = 1;
2117                         break;
2118                 }
2119                 /* fallthru */
2120         default:
2121                 /* nothing */
2122                 ;
2123         }
2124
2125         if (hashcmp(one->sha1, two->sha1)) {
2126                 int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
2127
2128                 if (DIFF_OPT_TST(o, BINARY)) {
2129                         mmfile_t mf;
2130                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
2131                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
2132                                 abbrev = 40;
2133                 }
2134                 strbuf_addf(&msg, "index %.*s..%.*s",
2135                                 abbrev, sha1_to_hex(one->sha1),
2136                                 abbrev, sha1_to_hex(two->sha1));
2137                 if (one->mode == two->mode)
2138                         strbuf_addf(&msg, " %06o", one->mode);
2139                 strbuf_addch(&msg, '\n');
2140         }
2141
2142         if (msg.len)
2143                 strbuf_setlen(&msg, msg.len - 1);
2144         xfrm_msg = msg.len ? msg.buf : NULL;
2145
2146         if (!pgm &&
2147             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
2148             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
2149                 /* a filepair that changes between file and symlink
2150                  * needs to be split into deletion and creation.
2151                  */
2152                 struct diff_filespec *null = alloc_filespec(two->path);
2153                 run_diff_cmd(NULL, name, other, attr_path,
2154                              one, null, xfrm_msg, o, 0);
2155                 free(null);
2156                 null = alloc_filespec(one->path);
2157                 run_diff_cmd(NULL, name, other, attr_path,
2158                              null, two, xfrm_msg, o, 0);
2159                 free(null);
2160         }
2161         else
2162                 run_diff_cmd(pgm, name, other, attr_path,
2163                              one, two, xfrm_msg, o, complete_rewrite);
2164
2165         strbuf_release(&msg);
2166 }
2167
2168 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
2169                          struct diffstat_t *diffstat)
2170 {
2171         const char *name;
2172         const char *other;
2173         int complete_rewrite = 0;
2174
2175         if (DIFF_PAIR_UNMERGED(p)) {
2176                 /* unmerged */
2177                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, 0);
2178                 return;
2179         }
2180
2181         name = p->one->path;
2182         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2183
2184         if (o->prefix_length)
2185                 strip_prefix(o->prefix_length, &name, &other);
2186
2187         diff_fill_sha1_info(p->one);
2188         diff_fill_sha1_info(p->two);
2189
2190         if (p->status == DIFF_STATUS_MODIFIED && p->score)
2191                 complete_rewrite = 1;
2192         builtin_diffstat(name, other, p->one, p->two, diffstat, o, complete_rewrite);
2193 }
2194
2195 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
2196 {
2197         const char *name;
2198         const char *other;
2199         const char *attr_path;
2200
2201         if (DIFF_PAIR_UNMERGED(p)) {
2202                 /* unmerged */
2203                 return;
2204         }
2205
2206         name = p->one->path;
2207         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2208         attr_path = other ? other : name;
2209
2210         if (o->prefix_length)
2211                 strip_prefix(o->prefix_length, &name, &other);
2212
2213         diff_fill_sha1_info(p->one);
2214         diff_fill_sha1_info(p->two);
2215
2216         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
2217 }
2218
2219 void diff_setup(struct diff_options *options)
2220 {
2221         memset(options, 0, sizeof(*options));
2222
2223         options->file = stdout;
2224
2225         options->line_termination = '\n';
2226         options->break_opt = -1;
2227         options->rename_limit = -1;
2228         options->dirstat_percent = 3;
2229         options->context = 3;
2230
2231         options->change = diff_change;
2232         options->add_remove = diff_addremove;
2233         if (diff_use_color_default > 0)
2234                 DIFF_OPT_SET(options, COLOR_DIFF);
2235         else
2236                 DIFF_OPT_CLR(options, COLOR_DIFF);
2237         options->detect_rename = diff_detect_rename_default;
2238
2239         options->a_prefix = "a/";
2240         options->b_prefix = "b/";
2241 }
2242
2243 int diff_setup_done(struct diff_options *options)
2244 {
2245         int count = 0;
2246
2247         if (options->output_format & DIFF_FORMAT_NAME)
2248                 count++;
2249         if (options->output_format & DIFF_FORMAT_NAME_STATUS)
2250                 count++;
2251         if (options->output_format & DIFF_FORMAT_CHECKDIFF)
2252                 count++;
2253         if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
2254                 count++;
2255         if (count > 1)
2256                 die("--name-only, --name-status, --check and -s are mutually exclusive");
2257
2258         if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
2259                 options->detect_rename = DIFF_DETECT_COPY;
2260
2261         if (!DIFF_OPT_TST(options, RELATIVE_NAME))
2262                 options->prefix = NULL;
2263         if (options->prefix)
2264                 options->prefix_length = strlen(options->prefix);
2265         else
2266                 options->prefix_length = 0;
2267
2268         if (options->output_format & (DIFF_FORMAT_NAME |
2269                                       DIFF_FORMAT_NAME_STATUS |
2270                                       DIFF_FORMAT_CHECKDIFF |
2271                                       DIFF_FORMAT_NO_OUTPUT))
2272                 options->output_format &= ~(DIFF_FORMAT_RAW |
2273                                             DIFF_FORMAT_NUMSTAT |
2274                                             DIFF_FORMAT_DIFFSTAT |
2275                                             DIFF_FORMAT_SHORTSTAT |
2276                                             DIFF_FORMAT_DIRSTAT |
2277                                             DIFF_FORMAT_SUMMARY |
2278                                             DIFF_FORMAT_PATCH);
2279
2280         /*
2281          * These cases always need recursive; we do not drop caller-supplied
2282          * recursive bits for other formats here.
2283          */
2284         if (options->output_format & (DIFF_FORMAT_PATCH |
2285                                       DIFF_FORMAT_NUMSTAT |
2286                                       DIFF_FORMAT_DIFFSTAT |
2287                                       DIFF_FORMAT_SHORTSTAT |
2288                                       DIFF_FORMAT_DIRSTAT |
2289                                       DIFF_FORMAT_SUMMARY |
2290                                       DIFF_FORMAT_CHECKDIFF))
2291                 DIFF_OPT_SET(options, RECURSIVE);
2292         /*
2293          * Also pickaxe would not work very well if you do not say recursive
2294          */
2295         if (options->pickaxe)
2296                 DIFF_OPT_SET(options, RECURSIVE);
2297
2298         if (options->detect_rename && options->rename_limit < 0)
2299                 options->rename_limit = diff_rename_limit_default;
2300         if (options->setup & DIFF_SETUP_USE_CACHE) {
2301                 if (!active_cache)
2302                         /* read-cache does not die even when it fails
2303                          * so it is safe for us to do this here.  Also
2304                          * it does not smudge active_cache or active_nr
2305                          * when it fails, so we do not have to worry about
2306                          * cleaning it up ourselves either.
2307                          */
2308                         read_cache();
2309         }
2310         if (options->abbrev <= 0 || 40 < options->abbrev)
2311                 options->abbrev = 40; /* full */
2312
2313         /*
2314          * It does not make sense to show the first hit we happened
2315          * to have found.  It does not make sense not to return with
2316          * exit code in such a case either.
2317          */
2318         if (DIFF_OPT_TST(options, QUIET)) {
2319                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
2320                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
2321         }
2322
2323         /*
2324          * If we postprocess in diffcore, we cannot simply return
2325          * upon the first hit.  We need to run diff as usual.
2326          */
2327         if (options->pickaxe || options->filter)
2328                 DIFF_OPT_CLR(options, QUIET);
2329
2330         return 0;
2331 }
2332
2333 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
2334 {
2335         char c, *eq;
2336         int len;
2337
2338         if (*arg != '-')
2339                 return 0;
2340         c = *++arg;
2341         if (!c)
2342                 return 0;
2343         if (c == arg_short) {
2344                 c = *++arg;
2345                 if (!c)
2346                         return 1;
2347                 if (val && isdigit(c)) {
2348                         char *end;
2349                         int n = strtoul(arg, &end, 10);
2350                         if (*end)
2351                                 return 0;
2352                         *val = n;
2353                         return 1;
2354                 }
2355                 return 0;
2356         }
2357         if (c != '-')
2358                 return 0;
2359         arg++;
2360         eq = strchr(arg, '=');
2361         if (eq)
2362                 len = eq - arg;
2363         else
2364                 len = strlen(arg);
2365         if (!len || strncmp(arg, arg_long, len))
2366                 return 0;
2367         if (eq) {
2368                 int n;
2369                 char *end;
2370                 if (!isdigit(*++eq))
2371                         return 0;
2372                 n = strtoul(eq, &end, 10);
2373                 if (*end)
2374                         return 0;
2375                 *val = n;
2376         }
2377         return 1;
2378 }
2379
2380 static int diff_scoreopt_parse(const char *opt);
2381
2382 int diff_opt_parse(struct diff_options *options, const char **av, int ac)
2383 {
2384         const char *arg = av[0];
2385
2386         /* Output format options */
2387         if (!strcmp(arg, "-p") || !strcmp(arg, "-u"))
2388                 options->output_format |= DIFF_FORMAT_PATCH;
2389         else if (opt_arg(arg, 'U', "unified", &options->context))
2390                 options->output_format |= DIFF_FORMAT_PATCH;
2391         else if (!strcmp(arg, "--raw"))
2392                 options->output_format |= DIFF_FORMAT_RAW;
2393         else if (!strcmp(arg, "--patch-with-raw"))
2394                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW;
2395         else if (!strcmp(arg, "--numstat"))
2396                 options->output_format |= DIFF_FORMAT_NUMSTAT;
2397         else if (!strcmp(arg, "--shortstat"))
2398                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
2399         else if (opt_arg(arg, 'X', "dirstat", &options->dirstat_percent))
2400                 options->output_format |= DIFF_FORMAT_DIRSTAT;
2401         else if (!strcmp(arg, "--cumulative"))
2402                 options->output_format |= DIFF_FORMAT_CUMULATIVE;
2403         else if (!strcmp(arg, "--check"))
2404                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
2405         else if (!strcmp(arg, "--summary"))
2406                 options->output_format |= DIFF_FORMAT_SUMMARY;
2407         else if (!strcmp(arg, "--patch-with-stat"))
2408                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT;
2409         else if (!strcmp(arg, "--name-only"))
2410                 options->output_format |= DIFF_FORMAT_NAME;
2411         else if (!strcmp(arg, "--name-status"))
2412                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
2413         else if (!strcmp(arg, "-s"))
2414                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
2415         else if (!prefixcmp(arg, "--stat")) {
2416                 char *end;
2417                 int width = options->stat_width;
2418                 int name_width = options->stat_name_width;
2419                 arg += 6;
2420                 end = (char *)arg;
2421
2422                 switch (*arg) {
2423                 case '-':
2424                         if (!prefixcmp(arg, "-width="))
2425                                 width = strtoul(arg + 7, &end, 10);
2426                         else if (!prefixcmp(arg, "-name-width="))
2427                                 name_width = strtoul(arg + 12, &end, 10);
2428                         break;
2429                 case '=':
2430                         width = strtoul(arg+1, &end, 10);
2431                         if (*end == ',')
2432                                 name_width = strtoul(end+1, &end, 10);
2433                 }
2434
2435                 /* Important! This checks all the error cases! */
2436                 if (*end)
2437                         return 0;
2438                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
2439                 options->stat_name_width = name_width;
2440                 options->stat_width = width;
2441         }
2442
2443         /* renames options */
2444         else if (!prefixcmp(arg, "-B")) {
2445                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
2446                         return -1;
2447         }
2448         else if (!prefixcmp(arg, "-M")) {
2449                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
2450                         return -1;
2451                 options->detect_rename = DIFF_DETECT_RENAME;
2452         }
2453         else if (!prefixcmp(arg, "-C")) {
2454                 if (options->detect_rename == DIFF_DETECT_COPY)
2455                         DIFF_OPT_SET(options, FIND_COPIES_HARDER);
2456                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
2457                         return -1;
2458                 options->detect_rename = DIFF_DETECT_COPY;
2459         }
2460         else if (!strcmp(arg, "--no-renames"))
2461                 options->detect_rename = 0;
2462         else if (!strcmp(arg, "--relative"))
2463                 DIFF_OPT_SET(options, RELATIVE_NAME);
2464         else if (!prefixcmp(arg, "--relative=")) {
2465                 DIFF_OPT_SET(options, RELATIVE_NAME);
2466                 options->prefix = arg + 11;
2467         }
2468
2469         /* xdiff options */
2470         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
2471                 options->xdl_opts |= XDF_IGNORE_WHITESPACE;
2472         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
2473                 options->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
2474         else if (!strcmp(arg, "--ignore-space-at-eol"))
2475                 options->xdl_opts |= XDF_IGNORE_WHITESPACE_AT_EOL;
2476
2477         /* flags options */
2478         else if (!strcmp(arg, "--binary")) {
2479                 options->output_format |= DIFF_FORMAT_PATCH;
2480                 DIFF_OPT_SET(options, BINARY);
2481         }
2482         else if (!strcmp(arg, "--full-index"))
2483                 DIFF_OPT_SET(options, FULL_INDEX);
2484         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
2485                 DIFF_OPT_SET(options, TEXT);
2486         else if (!strcmp(arg, "-R"))
2487                 DIFF_OPT_SET(options, REVERSE_DIFF);
2488         else if (!strcmp(arg, "--find-copies-harder"))
2489                 DIFF_OPT_SET(options, FIND_COPIES_HARDER);
2490         else if (!strcmp(arg, "--follow"))
2491                 DIFF_OPT_SET(options, FOLLOW_RENAMES);
2492         else if (!strcmp(arg, "--color"))
2493                 DIFF_OPT_SET(options, COLOR_DIFF);
2494         else if (!strcmp(arg, "--no-color"))
2495                 DIFF_OPT_CLR(options, COLOR_DIFF);
2496         else if (!strcmp(arg, "--color-words"))
2497                 options->flags |= DIFF_OPT_COLOR_DIFF | DIFF_OPT_COLOR_DIFF_WORDS;
2498         else if (!strcmp(arg, "--exit-code"))
2499                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
2500         else if (!strcmp(arg, "--quiet"))
2501                 DIFF_OPT_SET(options, QUIET);
2502         else if (!strcmp(arg, "--ext-diff"))
2503                 DIFF_OPT_SET(options, ALLOW_EXTERNAL);
2504         else if (!strcmp(arg, "--no-ext-diff"))
2505                 DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
2506         else if (!strcmp(arg, "--ignore-submodules"))
2507                 DIFF_OPT_SET(options, IGNORE_SUBMODULES);
2508
2509         /* misc options */
2510         else if (!strcmp(arg, "-z"))
2511                 options->line_termination = 0;
2512         else if (!prefixcmp(arg, "-l"))
2513                 options->rename_limit = strtoul(arg+2, NULL, 10);
2514         else if (!prefixcmp(arg, "-S"))
2515                 options->pickaxe = arg + 2;
2516         else if (!strcmp(arg, "--pickaxe-all"))
2517                 options->pickaxe_opts = DIFF_PICKAXE_ALL;
2518         else if (!strcmp(arg, "--pickaxe-regex"))
2519                 options->pickaxe_opts = DIFF_PICKAXE_REGEX;
2520         else if (!prefixcmp(arg, "-O"))
2521                 options->orderfile = arg + 2;
2522         else if (!prefixcmp(arg, "--diff-filter="))
2523                 options->filter = arg + 14;
2524         else if (!strcmp(arg, "--abbrev"))
2525                 options->abbrev = DEFAULT_ABBREV;
2526         else if (!prefixcmp(arg, "--abbrev=")) {
2527                 options->abbrev = strtoul(arg + 9, NULL, 10);
2528                 if (options->abbrev < MINIMUM_ABBREV)
2529                         options->abbrev = MINIMUM_ABBREV;
2530                 else if (40 < options->abbrev)
2531                         options->abbrev = 40;
2532         }
2533         else if (!prefixcmp(arg, "--src-prefix="))
2534                 options->a_prefix = arg + 13;
2535         else if (!prefixcmp(arg, "--dst-prefix="))
2536                 options->b_prefix = arg + 13;
2537         else if (!strcmp(arg, "--no-prefix"))
2538                 options->a_prefix = options->b_prefix = "";
2539         else if (!prefixcmp(arg, "--output=")) {
2540                 options->file = fopen(arg + strlen("--output="), "w");
2541                 options->close_file = 1;
2542         } else
2543                 return 0;
2544         return 1;
2545 }
2546
2547 static int parse_num(const char **cp_p)
2548 {
2549         unsigned long num, scale;
2550         int ch, dot;
2551         const char *cp = *cp_p;
2552
2553         num = 0;
2554         scale = 1;
2555         dot = 0;
2556         for(;;) {
2557                 ch = *cp;
2558                 if ( !dot && ch == '.' ) {
2559                         scale = 1;
2560                         dot = 1;
2561                 } else if ( ch == '%' ) {
2562                         scale = dot ? scale*100 : 100;
2563                         cp++;   /* % is always at the end */
2564                         break;
2565                 } else if ( ch >= '0' && ch <= '9' ) {
2566                         if ( scale < 100000 ) {
2567                                 scale *= 10;
2568                                 num = (num*10) + (ch-'0');
2569                         }
2570                 } else {
2571                         break;
2572                 }
2573                 cp++;
2574         }
2575         *cp_p = cp;
2576
2577         /* user says num divided by scale and we say internally that
2578          * is MAX_SCORE * num / scale.
2579          */
2580         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
2581 }
2582
2583 static int diff_scoreopt_parse(const char *opt)
2584 {
2585         int opt1, opt2, cmd;
2586
2587         if (*opt++ != '-')
2588                 return -1;
2589         cmd = *opt++;
2590         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
2591                 return -1; /* that is not a -M, -C nor -B option */
2592
2593         opt1 = parse_num(&opt);
2594         if (cmd != 'B')
2595                 opt2 = 0;
2596         else {
2597                 if (*opt == 0)
2598                         opt2 = 0;
2599                 else if (*opt != '/')
2600                         return -1; /* we expect -B80/99 or -B80 */
2601                 else {
2602                         opt++;
2603                         opt2 = parse_num(&opt);
2604                 }
2605         }
2606         if (*opt != 0)
2607                 return -1;
2608         return opt1 | (opt2 << 16);
2609 }
2610
2611 struct diff_queue_struct diff_queued_diff;
2612
2613 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
2614 {
2615         if (queue->alloc <= queue->nr) {
2616                 queue->alloc = alloc_nr(queue->alloc);
2617                 queue->queue = xrealloc(queue->queue,
2618                                         sizeof(dp) * queue->alloc);
2619         }
2620         queue->queue[queue->nr++] = dp;
2621 }
2622
2623 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
2624                                  struct diff_filespec *one,
2625                                  struct diff_filespec *two)
2626 {
2627         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
2628         dp->one = one;
2629         dp->two = two;
2630         if (queue)
2631                 diff_q(queue, dp);
2632         return dp;
2633 }
2634
2635 void diff_free_filepair(struct diff_filepair *p)
2636 {
2637         free_filespec(p->one);
2638         free_filespec(p->two);
2639         free(p);
2640 }
2641
2642 /* This is different from find_unique_abbrev() in that
2643  * it stuffs the result with dots for alignment.
2644  */
2645 const char *diff_unique_abbrev(const unsigned char *sha1, int len)
2646 {
2647         int abblen;
2648         const char *abbrev;
2649         if (len == 40)
2650                 return sha1_to_hex(sha1);
2651
2652         abbrev = find_unique_abbrev(sha1, len);
2653         abblen = strlen(abbrev);
2654         if (abblen < 37) {
2655                 static char hex[41];
2656                 if (len < abblen && abblen <= len + 2)
2657                         sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
2658                 else
2659                         sprintf(hex, "%s...", abbrev);
2660                 return hex;
2661         }
2662         return sha1_to_hex(sha1);
2663 }
2664
2665 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
2666 {
2667         int line_termination = opt->line_termination;
2668         int inter_name_termination = line_termination ? '\t' : '\0';
2669
2670         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
2671                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
2672                         diff_unique_abbrev(p->one->sha1, opt->abbrev));
2673                 fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
2674         }
2675         if (p->score) {
2676                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
2677                         inter_name_termination);
2678         } else {
2679                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
2680         }
2681
2682         if (p->status == DIFF_STATUS_COPIED ||
2683             p->status == DIFF_STATUS_RENAMED) {
2684                 const char *name_a, *name_b;
2685                 name_a = p->one->path;
2686                 name_b = p->two->path;
2687                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2688                 write_name_quoted(name_a, opt->file, inter_name_termination);
2689                 write_name_quoted(name_b, opt->file, line_termination);
2690         } else {
2691                 const char *name_a, *name_b;
2692                 name_a = p->one->mode ? p->one->path : p->two->path;
2693                 name_b = NULL;
2694                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2695                 write_name_quoted(name_a, opt->file, line_termination);
2696         }
2697 }
2698
2699 int diff_unmodified_pair(struct diff_filepair *p)
2700 {
2701         /* This function is written stricter than necessary to support
2702          * the currently implemented transformers, but the idea is to
2703          * let transformers to produce diff_filepairs any way they want,
2704          * and filter and clean them up here before producing the output.
2705          */
2706         struct diff_filespec *one = p->one, *two = p->two;
2707
2708         if (DIFF_PAIR_UNMERGED(p))
2709                 return 0; /* unmerged is interesting */
2710
2711         /* deletion, addition, mode or type change
2712          * and rename are all interesting.
2713          */
2714         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
2715             DIFF_PAIR_MODE_CHANGED(p) ||
2716             strcmp(one->path, two->path))
2717                 return 0;
2718
2719         /* both are valid and point at the same path.  that is, we are
2720          * dealing with a change.
2721          */
2722         if (one->sha1_valid && two->sha1_valid &&
2723             !hashcmp(one->sha1, two->sha1))
2724                 return 1; /* no change */
2725         if (!one->sha1_valid && !two->sha1_valid)
2726                 return 1; /* both look at the same file on the filesystem. */
2727         return 0;
2728 }
2729
2730 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
2731 {
2732         if (diff_unmodified_pair(p))
2733                 return;
2734
2735         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2736             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2737                 return; /* no tree diffs in patch format */
2738
2739         run_diff(p, o);
2740 }
2741
2742 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
2743                             struct diffstat_t *diffstat)
2744 {
2745         if (diff_unmodified_pair(p))
2746                 return;
2747
2748         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2749             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2750                 return; /* no tree diffs in patch format */
2751
2752         run_diffstat(p, o, diffstat);
2753 }
2754
2755 static void diff_flush_checkdiff(struct diff_filepair *p,
2756                 struct diff_options *o)
2757 {
2758         if (diff_unmodified_pair(p))
2759                 return;
2760
2761         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2762             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2763                 return; /* no tree diffs in patch format */
2764
2765         run_checkdiff(p, o);
2766 }
2767
2768 int diff_queue_is_empty(void)
2769 {
2770         struct diff_queue_struct *q = &diff_queued_diff;
2771         int i;
2772         for (i = 0; i < q->nr; i++)
2773                 if (!diff_unmodified_pair(q->queue[i]))
2774                         return 0;
2775         return 1;
2776 }
2777
2778 #if DIFF_DEBUG
2779 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
2780 {
2781         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
2782                 x, one ? one : "",
2783                 s->path,
2784                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
2785                 s->mode,
2786                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
2787         fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
2788                 x, one ? one : "",
2789                 s->size, s->xfrm_flags);
2790 }
2791
2792 void diff_debug_filepair(const struct diff_filepair *p, int i)
2793 {
2794         diff_debug_filespec(p->one, i, "one");
2795         diff_debug_filespec(p->two, i, "two");
2796         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
2797                 p->score, p->status ? p->status : '?',
2798                 p->one->rename_used, p->broken_pair);
2799 }
2800
2801 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
2802 {
2803         int i;
2804         if (msg)
2805                 fprintf(stderr, "%s\n", msg);
2806         fprintf(stderr, "q->nr = %d\n", q->nr);
2807         for (i = 0; i < q->nr; i++) {
2808                 struct diff_filepair *p = q->queue[i];
2809                 diff_debug_filepair(p, i);
2810         }
2811 }
2812 #endif
2813
2814 static void diff_resolve_rename_copy(void)
2815 {
2816         int i;
2817         struct diff_filepair *p;
2818         struct diff_queue_struct *q = &diff_queued_diff;
2819
2820         diff_debug_queue("resolve-rename-copy", q);
2821
2822         for (i = 0; i < q->nr; i++) {
2823                 p = q->queue[i];
2824                 p->status = 0; /* undecided */
2825                 if (DIFF_PAIR_UNMERGED(p))
2826                         p->status = DIFF_STATUS_UNMERGED;
2827                 else if (!DIFF_FILE_VALID(p->one))
2828                         p->status = DIFF_STATUS_ADDED;
2829                 else if (!DIFF_FILE_VALID(p->two))
2830                         p->status = DIFF_STATUS_DELETED;
2831                 else if (DIFF_PAIR_TYPE_CHANGED(p))
2832                         p->status = DIFF_STATUS_TYPE_CHANGED;
2833
2834                 /* from this point on, we are dealing with a pair
2835                  * whose both sides are valid and of the same type, i.e.
2836                  * either in-place edit or rename/copy edit.
2837                  */
2838                 else if (DIFF_PAIR_RENAME(p)) {
2839                         /*
2840                          * A rename might have re-connected a broken
2841                          * pair up, causing the pathnames to be the
2842                          * same again. If so, that's not a rename at
2843                          * all, just a modification..
2844                          *
2845                          * Otherwise, see if this source was used for
2846                          * multiple renames, in which case we decrement
2847                          * the count, and call it a copy.
2848                          */
2849                         if (!strcmp(p->one->path, p->two->path))
2850                                 p->status = DIFF_STATUS_MODIFIED;
2851                         else if (--p->one->rename_used > 0)
2852                                 p->status = DIFF_STATUS_COPIED;
2853                         else
2854                                 p->status = DIFF_STATUS_RENAMED;
2855                 }
2856                 else if (hashcmp(p->one->sha1, p->two->sha1) ||
2857                          p->one->mode != p->two->mode ||
2858                          is_null_sha1(p->one->sha1))
2859                         p->status = DIFF_STATUS_MODIFIED;
2860                 else {
2861                         /* This is a "no-change" entry and should not
2862                          * happen anymore, but prepare for broken callers.
2863                          */
2864                         error("feeding unmodified %s to diffcore",
2865                               p->one->path);
2866                         p->status = DIFF_STATUS_UNKNOWN;
2867                 }
2868         }
2869         diff_debug_queue("resolve-rename-copy done", q);
2870 }
2871
2872 static int check_pair_status(struct diff_filepair *p)
2873 {
2874         switch (p->status) {
2875         case DIFF_STATUS_UNKNOWN:
2876                 return 0;
2877         case 0:
2878                 die("internal error in diff-resolve-rename-copy");
2879         default:
2880                 return 1;
2881         }
2882 }
2883
2884 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
2885 {
2886         int fmt = opt->output_format;
2887
2888         if (fmt & DIFF_FORMAT_CHECKDIFF)
2889                 diff_flush_checkdiff(p, opt);
2890         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
2891                 diff_flush_raw(p, opt);
2892         else if (fmt & DIFF_FORMAT_NAME) {
2893                 const char *name_a, *name_b;
2894                 name_a = p->two->path;
2895                 name_b = NULL;
2896                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2897                 write_name_quoted(name_a, opt->file, opt->line_termination);
2898         }
2899 }
2900
2901 static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
2902 {
2903         if (fs->mode)
2904                 fprintf(file, " %s mode %06o ", newdelete, fs->mode);
2905         else
2906                 fprintf(file, " %s ", newdelete);
2907         write_name_quoted(fs->path, file, '\n');
2908 }
2909
2910
2911 static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name)
2912 {
2913         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
2914                 fprintf(file, " mode change %06o => %06o%c", p->one->mode, p->two->mode,
2915                         show_name ? ' ' : '\n');
2916                 if (show_name) {
2917                         write_name_quoted(p->two->path, file, '\n');
2918                 }
2919         }
2920 }
2921
2922 static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p)
2923 {
2924         char *names = pprint_rename(p->one->path, p->two->path);
2925
2926         fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
2927         free(names);
2928         show_mode_change(file, p, 0);
2929 }
2930
2931 static void diff_summary(FILE *file, struct diff_filepair *p)
2932 {
2933         switch(p->status) {
2934         case DIFF_STATUS_DELETED:
2935                 show_file_mode_name(file, "delete", p->one);
2936                 break;
2937         case DIFF_STATUS_ADDED:
2938                 show_file_mode_name(file, "create", p->two);
2939                 break;
2940         case DIFF_STATUS_COPIED:
2941                 show_rename_copy(file, "copy", p);
2942                 break;
2943         case DIFF_STATUS_RENAMED:
2944                 show_rename_copy(file, "rename", p);
2945                 break;
2946         default:
2947                 if (p->score) {
2948                         fputs(" rewrite ", file);
2949                         write_name_quoted(p->two->path, file, ' ');
2950                         fprintf(file, "(%d%%)\n", similarity_index(p));
2951                 }
2952                 show_mode_change(file, p, !p->score);
2953                 break;
2954         }
2955 }
2956
2957 struct patch_id_t {
2958         struct xdiff_emit_state xm;
2959         SHA_CTX *ctx;
2960         int patchlen;
2961 };
2962
2963 static int remove_space(char *line, int len)
2964 {
2965         int i;
2966         char *dst = line;
2967         unsigned char c;
2968
2969         for (i = 0; i < len; i++)
2970                 if (!isspace((c = line[i])))
2971                         *dst++ = c;
2972
2973         return dst - line;
2974 }
2975
2976 static void patch_id_consume(void *priv, char *line, unsigned long len)
2977 {
2978         struct patch_id_t *data = priv;
2979         int new_len;
2980
2981         /* Ignore line numbers when computing the SHA1 of the patch */
2982         if (!prefixcmp(line, "@@ -"))
2983                 return;
2984
2985         new_len = remove_space(line, len);
2986
2987         SHA1_Update(data->ctx, line, new_len);
2988         data->patchlen += new_len;
2989 }
2990
2991 /* returns 0 upon success, and writes result into sha1 */
2992 static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
2993 {
2994         struct diff_queue_struct *q = &diff_queued_diff;
2995         int i;
2996         SHA_CTX ctx;
2997         struct patch_id_t data;
2998         char buffer[PATH_MAX * 4 + 20];
2999
3000         SHA1_Init(&ctx);
3001         memset(&data, 0, sizeof(struct patch_id_t));
3002         data.ctx = &ctx;
3003         data.xm.consume = patch_id_consume;
3004
3005         for (i = 0; i < q->nr; i++) {
3006                 xpparam_t xpp;
3007                 xdemitconf_t xecfg;
3008                 xdemitcb_t ecb;
3009                 mmfile_t mf1, mf2;
3010                 struct diff_filepair *p = q->queue[i];
3011                 int len1, len2;
3012
3013                 memset(&xecfg, 0, sizeof(xecfg));
3014                 if (p->status == 0)
3015                         return error("internal diff status error");
3016                 if (p->status == DIFF_STATUS_UNKNOWN)
3017                         continue;
3018                 if (diff_unmodified_pair(p))
3019                         continue;
3020                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3021                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3022                         continue;
3023                 if (DIFF_PAIR_UNMERGED(p))
3024                         continue;
3025
3026                 diff_fill_sha1_info(p->one);
3027                 diff_fill_sha1_info(p->two);
3028                 if (fill_mmfile(&mf1, p->one) < 0 ||
3029                                 fill_mmfile(&mf2, p->two) < 0)
3030                         return error("unable to read files to diff");
3031
3032                 len1 = remove_space(p->one->path, strlen(p->one->path));
3033                 len2 = remove_space(p->two->path, strlen(p->two->path));
3034                 if (p->one->mode == 0)
3035                         len1 = snprintf(buffer, sizeof(buffer),
3036                                         "diff--gita/%.*sb/%.*s"
3037                                         "newfilemode%06o"
3038                                         "---/dev/null"
3039                                         "+++b/%.*s",
3040                                         len1, p->one->path,
3041                                         len2, p->two->path,
3042                                         p->two->mode,
3043                                         len2, p->two->path);
3044                 else if (p->two->mode == 0)
3045                         len1 = snprintf(buffer, sizeof(buffer),
3046                                         "diff--gita/%.*sb/%.*s"
3047                                         "deletedfilemode%06o"
3048                                         "---a/%.*s"
3049                                         "+++/dev/null",
3050                                         len1, p->one->path,
3051                                         len2, p->two->path,
3052                                         p->one->mode,
3053                                         len1, p->one->path);
3054                 else
3055                         len1 = snprintf(buffer, sizeof(buffer),
3056                                         "diff--gita/%.*sb/%.*s"
3057                                         "---a/%.*s"
3058                                         "+++b/%.*s",
3059                                         len1, p->one->path,
3060                                         len2, p->two->path,
3061                                         len1, p->one->path,
3062                                         len2, p->two->path);
3063                 SHA1_Update(&ctx, buffer, len1);
3064
3065                 xpp.flags = XDF_NEED_MINIMAL;
3066                 xecfg.ctxlen = 3;
3067                 xecfg.flags = XDL_EMIT_FUNCNAMES;
3068                 ecb.outf = xdiff_outf;
3069                 ecb.priv = &data;
3070                 xdi_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
3071         }
3072
3073         SHA1_Final(sha1, &ctx);
3074         return 0;
3075 }
3076
3077 int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
3078 {
3079         struct diff_queue_struct *q = &diff_queued_diff;
3080         int i;
3081         int result = diff_get_patch_id(options, sha1);
3082
3083         for (i = 0; i < q->nr; i++)
3084                 diff_free_filepair(q->queue[i]);
3085
3086         free(q->queue);
3087         q->queue = NULL;
3088         q->nr = q->alloc = 0;
3089
3090         return result;
3091 }
3092
3093 static int is_summary_empty(const struct diff_queue_struct *q)
3094 {
3095         int i;
3096
3097         for (i = 0; i < q->nr; i++) {
3098                 const struct diff_filepair *p = q->queue[i];
3099
3100                 switch (p->status) {
3101                 case DIFF_STATUS_DELETED:
3102                 case DIFF_STATUS_ADDED:
3103                 case DIFF_STATUS_COPIED:
3104                 case DIFF_STATUS_RENAMED:
3105                         return 0;
3106                 default:
3107                         if (p->score)
3108                                 return 0;
3109                         if (p->one->mode && p->two->mode &&
3110                             p->one->mode != p->two->mode)
3111                                 return 0;
3112                         break;
3113                 }
3114         }
3115         return 1;
3116 }
3117
3118 void diff_flush(struct diff_options *options)
3119 {
3120         struct diff_queue_struct *q = &diff_queued_diff;
3121         int i, output_format = options->output_format;
3122         int separator = 0;
3123
3124         /*
3125          * Order: raw, stat, summary, patch
3126          * or:    name/name-status/checkdiff (other bits clear)
3127          */
3128         if (!q->nr)
3129                 goto free_queue;
3130
3131         if (output_format & (DIFF_FORMAT_RAW |
3132                              DIFF_FORMAT_NAME |
3133                              DIFF_FORMAT_NAME_STATUS |
3134                              DIFF_FORMAT_CHECKDIFF)) {
3135                 for (i = 0; i < q->nr; i++) {
3136                         struct diff_filepair *p = q->queue[i];
3137                         if (check_pair_status(p))
3138                                 flush_one_pair(p, options);
3139                 }
3140                 separator++;
3141         }
3142
3143         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT)) {
3144                 struct diffstat_t diffstat;
3145
3146                 memset(&diffstat, 0, sizeof(struct diffstat_t));
3147                 diffstat.xm.consume = diffstat_consume;
3148                 for (i = 0; i < q->nr; i++) {
3149                         struct diff_filepair *p = q->queue[i];
3150                         if (check_pair_status(p))
3151                                 diff_flush_stat(p, options, &diffstat);
3152                 }
3153                 if (output_format & DIFF_FORMAT_NUMSTAT)
3154                         show_numstat(&diffstat, options);
3155                 if (output_format & DIFF_FORMAT_DIFFSTAT)
3156                         show_stats(&diffstat, options);
3157                 if (output_format & DIFF_FORMAT_SHORTSTAT)
3158                         show_shortstats(&diffstat, options);
3159                 free_diffstat_info(&diffstat);
3160                 separator++;
3161         }
3162         if (output_format & DIFF_FORMAT_DIRSTAT)
3163                 show_dirstat(options);
3164
3165         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
3166                 for (i = 0; i < q->nr; i++)
3167                         diff_summary(options->file, q->queue[i]);
3168                 separator++;
3169         }
3170
3171         if (output_format & DIFF_FORMAT_PATCH) {
3172                 if (separator) {
3173                         if (options->stat_sep) {
3174                                 /* attach patch instead of inline */
3175                                 fputs(options->stat_sep, options->file);
3176                         } else {
3177                                 putc(options->line_termination, options->file);
3178                         }
3179                 }
3180
3181                 for (i = 0; i < q->nr; i++) {
3182                         struct diff_filepair *p = q->queue[i];
3183                         if (check_pair_status(p))
3184                                 diff_flush_patch(p, options);
3185                 }
3186         }
3187
3188         if (output_format & DIFF_FORMAT_CALLBACK)
3189                 options->format_callback(q, options, options->format_callback_data);
3190
3191         for (i = 0; i < q->nr; i++)
3192                 diff_free_filepair(q->queue[i]);
3193 free_queue:
3194         free(q->queue);
3195         q->queue = NULL;
3196         q->nr = q->alloc = 0;
3197         if (options->close_file)
3198                 fclose(options->file);
3199 }
3200
3201 static void diffcore_apply_filter(const char *filter)
3202 {
3203         int i;
3204         struct diff_queue_struct *q = &diff_queued_diff;
3205         struct diff_queue_struct outq;
3206         outq.queue = NULL;
3207         outq.nr = outq.alloc = 0;
3208
3209         if (!filter)
3210                 return;
3211
3212         if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
3213                 int found;
3214                 for (i = found = 0; !found && i < q->nr; i++) {
3215                         struct diff_filepair *p = q->queue[i];
3216                         if (((p->status == DIFF_STATUS_MODIFIED) &&
3217                              ((p->score &&
3218                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
3219                               (!p->score &&
3220                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
3221                             ((p->status != DIFF_STATUS_MODIFIED) &&
3222                              strchr(filter, p->status)))
3223                                 found++;
3224                 }
3225                 if (found)
3226                         return;
3227
3228                 /* otherwise we will clear the whole queue
3229                  * by copying the empty outq at the end of this
3230                  * function, but first clear the current entries
3231                  * in the queue.
3232                  */
3233                 for (i = 0; i < q->nr; i++)
3234                         diff_free_filepair(q->queue[i]);
3235         }
3236         else {
3237                 /* Only the matching ones */
3238                 for (i = 0; i < q->nr; i++) {
3239                         struct diff_filepair *p = q->queue[i];
3240
3241                         if (((p->status == DIFF_STATUS_MODIFIED) &&
3242                              ((p->score &&
3243                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
3244                               (!p->score &&
3245                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
3246                             ((p->status != DIFF_STATUS_MODIFIED) &&
3247                              strchr(filter, p->status)))
3248                                 diff_q(&outq, p);
3249                         else
3250                                 diff_free_filepair(p);
3251                 }
3252         }
3253         free(q->queue);
3254         *q = outq;
3255 }
3256
3257 /* Check whether two filespecs with the same mode and size are identical */
3258 static int diff_filespec_is_identical(struct diff_filespec *one,
3259                                       struct diff_filespec *two)
3260 {
3261         if (S_ISGITLINK(one->mode))
3262                 return 0;
3263         if (diff_populate_filespec(one, 0))
3264                 return 0;
3265         if (diff_populate_filespec(two, 0))
3266                 return 0;
3267         return !memcmp(one->data, two->data, one->size);
3268 }
3269
3270 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
3271 {
3272         int i;
3273         struct diff_queue_struct *q = &diff_queued_diff;
3274         struct diff_queue_struct outq;
3275         outq.queue = NULL;
3276         outq.nr = outq.alloc = 0;
3277
3278         for (i = 0; i < q->nr; i++) {
3279                 struct diff_filepair *p = q->queue[i];
3280
3281                 /*
3282                  * 1. Entries that come from stat info dirtyness
3283                  *    always have both sides (iow, not create/delete),
3284                  *    one side of the object name is unknown, with
3285                  *    the same mode and size.  Keep the ones that
3286                  *    do not match these criteria.  They have real
3287                  *    differences.
3288                  *
3289                  * 2. At this point, the file is known to be modified,
3290                  *    with the same mode and size, and the object
3291                  *    name of one side is unknown.  Need to inspect
3292                  *    the identical contents.
3293                  */
3294                 if (!DIFF_FILE_VALID(p->one) || /* (1) */
3295                     !DIFF_FILE_VALID(p->two) ||
3296                     (p->one->sha1_valid && p->two->sha1_valid) ||
3297                     (p->one->mode != p->two->mode) ||
3298                     diff_populate_filespec(p->one, 1) ||
3299                     diff_populate_filespec(p->two, 1) ||
3300                     (p->one->size != p->two->size) ||
3301                     !diff_filespec_is_identical(p->one, p->two)) /* (2) */
3302                         diff_q(&outq, p);
3303                 else {
3304                         /*
3305                          * The caller can subtract 1 from skip_stat_unmatch
3306                          * to determine how many paths were dirty only
3307                          * due to stat info mismatch.
3308                          */
3309                         if (!DIFF_OPT_TST(diffopt, NO_INDEX))
3310                                 diffopt->skip_stat_unmatch++;
3311                         diff_free_filepair(p);
3312                 }
3313         }
3314         free(q->queue);
3315         *q = outq;
3316 }
3317
3318 void diffcore_std(struct diff_options *options)
3319 {
3320         if (DIFF_OPT_TST(options, QUIET))
3321                 return;
3322
3323         if (options->skip_stat_unmatch && !DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3324                 diffcore_skip_stat_unmatch(options);
3325         if (options->break_opt != -1)
3326                 diffcore_break(options->break_opt);
3327         if (options->detect_rename)
3328                 diffcore_rename(options);
3329         if (options->break_opt != -1)
3330                 diffcore_merge_broken();
3331         if (options->pickaxe)
3332                 diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
3333         if (options->orderfile)
3334                 diffcore_order(options->orderfile);
3335         diff_resolve_rename_copy();
3336         diffcore_apply_filter(options->filter);
3337
3338         if (diff_queued_diff.nr)
3339                 DIFF_OPT_SET(options, HAS_CHANGES);
3340         else
3341                 DIFF_OPT_CLR(options, HAS_CHANGES);
3342 }
3343
3344 int diff_result_code(struct diff_options *opt, int status)
3345 {
3346         int result = 0;
3347         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
3348             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
3349                 return status;
3350         if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
3351             DIFF_OPT_TST(opt, HAS_CHANGES))
3352                 result |= 01;
3353         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
3354             DIFF_OPT_TST(opt, CHECK_FAILED))
3355                 result |= 02;
3356         return result;
3357 }
3358
3359 void diff_addremove(struct diff_options *options,
3360                     int addremove, unsigned mode,
3361                     const unsigned char *sha1,
3362                     const char *base, const char *path)
3363 {
3364         char concatpath[PATH_MAX];
3365         struct diff_filespec *one, *two;
3366
3367         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES) && S_ISGITLINK(mode))
3368                 return;
3369
3370         /* This may look odd, but it is a preparation for
3371          * feeding "there are unchanged files which should
3372          * not produce diffs, but when you are doing copy
3373          * detection you would need them, so here they are"
3374          * entries to the diff-core.  They will be prefixed
3375          * with something like '=' or '*' (I haven't decided
3376          * which but should not make any difference).
3377          * Feeding the same new and old to diff_change()
3378          * also has the same effect.
3379          * Before the final output happens, they are pruned after
3380          * merged into rename/copy pairs as appropriate.
3381          */
3382         if (DIFF_OPT_TST(options, REVERSE_DIFF))
3383                 addremove = (addremove == '+' ? '-' :
3384                              addremove == '-' ? '+' : addremove);
3385
3386         if (!path) path = "";
3387         sprintf(concatpath, "%s%s", base, path);
3388
3389         if (options->prefix &&
3390             strncmp(concatpath, options->prefix, options->prefix_length))
3391                 return;
3392
3393         one = alloc_filespec(concatpath);
3394         two = alloc_filespec(concatpath);
3395
3396         if (addremove != '+')
3397                 fill_filespec(one, sha1, mode);
3398         if (addremove != '-')
3399                 fill_filespec(two, sha1, mode);
3400
3401         diff_queue(&diff_queued_diff, one, two);
3402         DIFF_OPT_SET(options, HAS_CHANGES);
3403 }
3404
3405 void diff_change(struct diff_options *options,
3406                  unsigned old_mode, unsigned new_mode,
3407                  const unsigned char *old_sha1,
3408                  const unsigned char *new_sha1,
3409                  const char *base, const char *path)
3410 {
3411         char concatpath[PATH_MAX];
3412         struct diff_filespec *one, *two;
3413
3414         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES) && S_ISGITLINK(old_mode)
3415                         && S_ISGITLINK(new_mode))
3416                 return;
3417
3418         if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
3419                 unsigned tmp;
3420                 const unsigned char *tmp_c;
3421                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
3422                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
3423         }
3424         if (!path) path = "";
3425         sprintf(concatpath, "%s%s", base, path);
3426
3427         if (options->prefix &&
3428             strncmp(concatpath, options->prefix, options->prefix_length))
3429                 return;
3430
3431         one = alloc_filespec(concatpath);
3432         two = alloc_filespec(concatpath);
3433         fill_filespec(one, old_sha1, old_mode);
3434         fill_filespec(two, new_sha1, new_mode);
3435
3436         diff_queue(&diff_queued_diff, one, two);
3437         DIFF_OPT_SET(options, HAS_CHANGES);
3438 }
3439
3440 void diff_unmerge(struct diff_options *options,
3441                   const char *path,
3442                   unsigned mode, const unsigned char *sha1)
3443 {
3444         struct diff_filespec *one, *two;
3445
3446         if (options->prefix &&
3447             strncmp(path, options->prefix, options->prefix_length))
3448                 return;
3449
3450         one = alloc_filespec(path);
3451         two = alloc_filespec(path);
3452         fill_filespec(one, sha1, mode);
3453         diff_queue(&diff_queued_diff, one, two)->is_unmerged = 1;
3454 }