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

   1 /*
   2  * Copyright (C) 2005 Junio C Hamano
   3  */
   4 #include "cache.h"
   5 #include "quote.h"
   6 #include "commit.h"
   7 #include "diff.h"
   8 #include "diffcore.h"
   9 #include "revision.h"
  10 #include "cache-tree.h"
  11 #include "path-list.h"
  12
  13 /*
  14  * diff-files
  15  */
  16
  17 static int read_directory(const char *path, struct path_list *list)
  18 {
  19         DIR *dir;
  20         struct dirent *e;
  21
  22         if (!(dir = opendir(path)))
  23                 return error("Could not open directory %s", path);
  24
  25         while ((e = readdir(dir)))
  26                 if (strcmp(".", e->d_name) && strcmp("..", e->d_name))
  27                         path_list_insert(e->d_name, list);
  28
  29         closedir(dir);
  30         return 0;
  31 }
  32
  33 static int get_mode(const char *path, int *mode)
  34 {
  35         struct stat st;
  36
  37         if (!path || !strcmp(path, "/dev/null"))
  38                 *mode = 0;
  39         else if (!strcmp(path, "-"))
  40                 *mode = ntohl(create_ce_mode(0666));
  41         else if (stat(path, &st))
  42                 return error("Could not access '%s'", path);
  43         else
  44                 *mode = st.st_mode;
  45         return 0;
  46 }
  47
  48 static int queue_diff(struct diff_options *o,
  49                 const char *name1, const char *name2)
  50 {
  51         int mode1 = 0, mode2 = 0;
  52
  53         if (get_mode(name1, &mode1) || get_mode(name2, &mode2))
  54                 return -1;
  55
  56         if (mode1 && mode2 && S_ISDIR(mode1) != S_ISDIR(mode2))
  57                 return error("file/directory conflict: %s, %s", name1, name2);
  58
  59         if (S_ISDIR(mode1) || S_ISDIR(mode2)) {
  60                 char buffer1[PATH_MAX], buffer2[PATH_MAX];
  61                 struct path_list p1 = {NULL, 0, 0, 1}, p2 = {NULL, 0, 0, 1};
  62                 int len1 = 0, len2 = 0, i1, i2, ret = 0;
  63
  64                 if (name1 && read_directory(name1, &p1))
  65                         return -1;
  66                 if (name2 && read_directory(name2, &p2)) {
  67                         path_list_clear(&p1, 0);
  68                         return -1;
  69                 }
  70
  71                 if (name1) {
  72                         len1 = strlen(name1);
  73                         if (len1 > 0 && name1[len1 - 1] == '/')
  74                                 len1--;
  75                         memcpy(buffer1, name1, len1);
  76                         buffer1[len1++] = '/';
  77                 }
  78
  79                 if (name2) {
  80                         len2 = strlen(name2);
  81                         if (len2 > 0 && name2[len2 - 1] == '/')
  82                                 len2--;
  83                         memcpy(buffer2, name2, len2);
  84                         buffer2[len2++] = '/';
  85                 }
  86
  87                 for (i1 = i2 = 0; !ret && (i1 < p1.nr || i2 < p2.nr); ) {
  88                         const char *n1, *n2;
  89                         int comp;
  90
  91                         if (i1 == p1.nr)
  92                                 comp = 1;
  93                         else if (i2 == p2.nr)
  94                                 comp = -1;
  95                         else
  96                                 comp = strcmp(p1.items[i1].path,
  97                                         p2.items[i2].path);
  98
  99                         if (comp > 0)
 100                                 n1 = NULL;
 101                         else {
 102                                 n1 = buffer1;
 103                                 strncpy(buffer1 + len1, p1.items[i1++].path,
 104                                                 PATH_MAX - len1);
 105                         }
 106
 107                         if (comp < 0)
 108                                 n2 = NULL;
 109                         else {
 110                                 n2 = buffer2;
 111                                 strncpy(buffer2 + len2, p2.items[i2++].path,
 112                                                 PATH_MAX - len2);
 113                         }
 114
 115                         ret = queue_diff(o, n1, n2);
 116                 }
 117                 path_list_clear(&p1, 0);
 118                 path_list_clear(&p2, 0);
 119
 120                 return ret;
 121         } else {
 122                 struct diff_filespec *d1, *d2;
 123
 124                 if (o->reverse_diff) {
 125                         unsigned tmp;
 126                         const char *tmp_c;
 127                         tmp = mode1; mode1 = mode2; mode2 = tmp;
 128                         tmp_c = name1; name1 = name2; name2 = tmp_c;
 129                 }
 130
 131                 if (!name1)
 132                         name1 = "/dev/null";
 133                 if (!name2)
 134                         name2 = "/dev/null";
 135                 d1 = alloc_filespec(name1);
 136                 d2 = alloc_filespec(name2);
 137                 fill_filespec(d1, null_sha1, mode1);
 138                 fill_filespec(d2, null_sha1, mode2);
 139
 140                 diff_queue(&diff_queued_diff, d1, d2);
 141                 return 0;
 142         }
 143 }
 144
 145 /*
 146  * Does the path name a blob in the working tree, or a directory
 147  * in the working tree?
 148  */
 149 static int is_in_index(const char *path)
 150 {
 151         int len, pos;
 152         struct cache_entry *ce;
 153
 154         len = strlen(path);
 155         while (path[len-1] == '/')
 156                 len--;
 157         if (!len)
 158                 return 1; /* "." */
 159         pos = cache_name_pos(path, len);
 160         if (0 <= pos)
 161                 return 1;
 162         pos = -1 - pos;
 163         while (pos < active_nr) {
 164                 ce = active_cache[pos++];
 165                 if (ce_namelen(ce) <= len ||
 166                     strncmp(ce->name, path, len) ||
 167                     (ce->name[len] > '/'))
 168                         break; /* path cannot be a prefix */
 169                 if (ce->name[len] == '/')
 170                         return 1;
 171         }
 172         return 0;
 173 }
 174
 175 static int handle_diff_files_args(struct rev_info *revs,
 176                 int argc, const char **argv, int *silent)
 177 {
 178         *silent = 0;
 179
 180         /* revs->max_count == -2 means --no-index */
 181         while (1 < argc && argv[1][0] == '-') {
 182                 if (!strcmp(argv[1], "--base"))
 183                         revs->max_count = 1;
 184                 else if (!strcmp(argv[1], "--ours"))
 185                         revs->max_count = 2;
 186                 else if (!strcmp(argv[1], "--theirs"))
 187                         revs->max_count = 3;
 188                 else if (!strcmp(argv[1], "-n") ||
 189                                 !strcmp(argv[1], "--no-index")) {
 190                         revs->max_count = -2;
 191                         revs->diffopt.exit_with_status = 1;
 192                         revs->diffopt.no_index = 1;
 193                 }
 194                 else if (!strcmp(argv[1], "-q"))
 195                         *silent = 1;
 196                 else
 197                         return error("invalid option: %s", argv[1]);
 198                 argv++; argc--;
 199         }
 200
 201         if (revs->max_count == -1 && revs->diffopt.nr_paths == 2) {
 202                 /*
 203                  * If two files are specified, and at least one is untracked,
 204                  * default to no-index.
 205                  */
 206                 read_cache();
 207                 if (!is_in_index(revs->diffopt.paths[0]) ||
 208                                         !is_in_index(revs->diffopt.paths[1])) {
 209                         revs->max_count = -2;
 210                         revs->diffopt.no_index = 1;
 211                 }
 212         }
 213
 214         /*
 215          * Make sure there are NO revision (i.e. pending object) parameter,
 216          * rev.max_count is reasonable (0 <= n <= 3),
 217          * there is no other revision filtering parameters.
 218          */
 219         if (revs->pending.nr || revs->max_count > 3 ||
 220             revs->min_age != -1 || revs->max_age != -1)
 221                 return error("no revision allowed with diff-files");
 222
 223         if (revs->max_count == -1 &&
 224             (revs->diffopt.output_format & DIFF_FORMAT_PATCH))
 225                 revs->combine_merges = revs->dense_combined_merges = 1;
 226
 227         return 0;
 228 }
 229
 230 static int is_outside_repo(const char *path, int nongit, const char *prefix)
 231 {
 232         int i;
 233         if (nongit || !strcmp(path, "-") || path[0] == '/')
 234                 return 1;
 235         if (prefixcmp(path, "../"))
 236                 return 0;
 237         if (!prefix)
 238                 return 1;
 239         for (i = strlen(prefix); !prefixcmp(path, "../"); ) {
 240                 while (i > 0 && prefix[i - 1] != '/')
 241                         i--;
 242                 if (--i < 0)
 243                         return 1;
 244                 path += 3;
 245         }
 246         return 0;
 247 }
 248
 249 int setup_diff_no_index(struct rev_info *revs,
 250                 int argc, const char ** argv, int nongit, const char *prefix)
 251 {
 252         int i;
 253         for (i = 1; i < argc; i++)
 254                 if (argv[i][0] != '-' || argv[i][1] == '\0')
 255                         break;
 256                 else if (!strcmp(argv[i], "--")) {
 257                         i++;
 258                         break;
 259                 } else if (i < argc - 3 && !strcmp(argv[i], "--no-index")) {
 260                         i = argc - 3;
 261                         revs->diffopt.exit_with_status = 1;
 262                         break;
 263                 }
 264         if (argc != i + 2 || (!is_outside_repo(argv[i + 1], nongit, prefix) &&
 265                                 !is_outside_repo(argv[i], nongit, prefix)))
 266                 return -1;
 267
 268         diff_setup(&revs->diffopt);
 269         for (i = 1; i < argc - 2; )
 270                 if (!strcmp(argv[i], "--no-index"))
 271                         i++;
 272                 else {
 273                         int j = diff_opt_parse(&revs->diffopt,
 274                                         argv + i, argc - i);
 275                         if (!j)
 276                                 die("invalid diff option/value: %s", argv[i]);
 277                         i += j;
 278                 }
 279
 280         if (prefix) {
 281                 int len = strlen(prefix);
 282
 283                 revs->diffopt.paths = xcalloc(2, sizeof(char*));
 284                 for (i = 0; i < 2; i++) {
 285                         const char *p = argv[argc - 2 + i];
 286                         /*
 287                          * stdin should be spelled as '-'; if you have
 288                          * path that is '-', spell it as ./-.
 289                          */
 290                         p = (strcmp(p, "-")
 291                              ? xstrdup(prefix_filename(prefix, len, p))
 292                              : p);
 293                         revs->diffopt.paths[i] = p;
 294                 }
 295         }
 296         else
 297                 revs->diffopt.paths = argv + argc - 2;
 298         revs->diffopt.nr_paths = 2;
 299         revs->diffopt.no_index = 1;
 300         revs->max_count = -2;
 301         if (diff_setup_done(&revs->diffopt) < 0)
 302                 die("diff_setup_done failed");
 303         return 0;
 304 }
 305
 306 int run_diff_files_cmd(struct rev_info *revs, int argc, const char **argv)
 307 {
 308         int silent_on_removed;
 309
 310         if (handle_diff_files_args(revs, argc, argv, &silent_on_removed))
 311                 return -1;
 312
 313         if (revs->diffopt.no_index) {
 314                 if (revs->diffopt.nr_paths != 2)
 315                         return error("need two files/directories with --no-index");
 316                 if (queue_diff(&revs->diffopt, revs->diffopt.paths[0],
 317                                 revs->diffopt.paths[1]))
 318                         return -1;
 319                 diffcore_std(&revs->diffopt);
 320                 diff_flush(&revs->diffopt);
 321                 /*
 322                  * The return code for --no-index imitates diff(1):
 323                  * 0 = no changes, 1 = changes, else error
 324                  */
 325                 return revs->diffopt.found_changes;
 326         }
 327
 328         if (read_cache() < 0) {
 329                 perror("read_cache");
 330                 return -1;
 331         }
 332         return run_diff_files(revs, silent_on_removed);
 333 }
 334
 335 int run_diff_files(struct rev_info *revs, int silent_on_removed)
 336 {
 337         int entries, i;
 338         int diff_unmerged_stage = revs->max_count;
 339
 340         if (diff_unmerged_stage < 0)
 341                 diff_unmerged_stage = 2;
 342         entries = active_nr;
 343         for (i = 0; i < entries; i++) {
 344                 struct stat st;
 345                 unsigned int oldmode, newmode;
 346                 struct cache_entry *ce = active_cache[i];
 347                 int changed;
 348
 349                 if (revs->diffopt.quiet && revs->diffopt.has_changes)
 350                         break;
 351
 352                 if (!ce_path_match(ce, revs->prune_data))
 353                         continue;
 354
 355                 if (ce_stage(ce)) {
 356                         struct combine_diff_path *dpath;
 357                         int num_compare_stages = 0;
 358                         size_t path_len;
 359
 360                         path_len = ce_namelen(ce);
 361
 362                         dpath = xmalloc(combine_diff_path_size(5, path_len));
 363                         dpath->path = (char *) &(dpath->parent[5]);
 364
 365                         dpath->next = NULL;
 366                         dpath->len = path_len;
 367                         memcpy(dpath->path, ce->name, path_len);
 368                         dpath->path[path_len] = '\0';
 369                         hashclr(dpath->sha1);
 370                         memset(&(dpath->parent[0]), 0,
 371                                sizeof(struct combine_diff_parent)*5);
 372
 373                         if (lstat(ce->name, &st) < 0) {
 374                                 if (errno != ENOENT && errno != ENOTDIR) {
 375                                         perror(ce->name);
 376                                         continue;
 377                                 }
 378                                 if (silent_on_removed)
 379                                         continue;
 380                         }
 381                         else
 382                                 dpath->mode = ntohl(ce_mode_from_stat(ce, st.st_mode));
 383
 384                         while (i < entries) {
 385                                 struct cache_entry *nce = active_cache[i];
 386                                 int stage;
 387
 388                                 if (strcmp(ce->name, nce->name))
 389                                         break;
 390
 391                                 /* Stage #2 (ours) is the first parent,
 392                                  * stage #3 (theirs) is the second.
 393                                  */
 394                                 stage = ce_stage(nce);
 395                                 if (2 <= stage) {
 396                                         int mode = ntohl(nce->ce_mode);
 397                                         num_compare_stages++;
 398                                         hashcpy(dpath->parent[stage-2].sha1, nce->sha1);
 399                                         dpath->parent[stage-2].mode = ntohl(ce_mode_from_stat(nce, mode));
 400                                         dpath->parent[stage-2].status =
 401                                                 DIFF_STATUS_MODIFIED;
 402                                 }
 403
 404                                 /* diff against the proper unmerged stage */
 405                                 if (stage == diff_unmerged_stage)
 406                                         ce = nce;
 407                                 i++;
 408                         }
 409                         /*
 410                          * Compensate for loop update
 411                          */
 412                         i--;
 413
 414                         if (revs->combine_merges && num_compare_stages == 2) {
 415                                 show_combined_diff(dpath, 2,
 416                                                    revs->dense_combined_merges,
 417                                                    revs);
 418                                 free(dpath);
 419                                 continue;
 420                         }
 421                         free(dpath);
 422                         dpath = NULL;
 423
 424                         /*
 425                          * Show the diff for the 'ce' if we found the one
 426                          * from the desired stage.
 427                          */
 428                         diff_unmerge(&revs->diffopt, ce->name, 0, null_sha1);
 429                         if (ce_stage(ce) != diff_unmerged_stage)
 430                                 continue;
 431                 }
 432
 433                 if (lstat(ce->name, &st) < 0) {
 434                         if (errno != ENOENT && errno != ENOTDIR) {
 435                                 perror(ce->name);
 436                                 continue;
 437                         }
 438                         if (silent_on_removed)
 439                                 continue;
 440                         diff_addremove(&revs->diffopt, '-', ntohl(ce->ce_mode),
 441                                        ce->sha1, ce->name, NULL);
 442                         continue;
 443                 }
 444                 changed = ce_match_stat(ce, &st, 0);
 445                 if (!changed && !revs->diffopt.find_copies_harder)
 446                         continue;
 447                 oldmode = ntohl(ce->ce_mode);
 448                 newmode = ntohl(ce_mode_from_stat(ce, st.st_mode));
 449                 diff_change(&revs->diffopt, oldmode, newmode,
 450                             ce->sha1, (changed ? null_sha1 : ce->sha1),
 451                             ce->name, NULL);
 452
 453         }
 454         diffcore_std(&revs->diffopt);
 455         diff_flush(&revs->diffopt);
 456         return 0;
 457 }
 458
 459 /*
 460  * diff-index
 461  */
 462
 463 /* A file entry went away or appeared */
 464 static void diff_index_show_file(struct rev_info *revs,
 465                                  const char *prefix,
 466                                  struct cache_entry *ce,
 467                                  unsigned char *sha1, unsigned int mode)
 468 {
 469         diff_addremove(&revs->diffopt, prefix[0], ntohl(mode),
 470                        sha1, ce->name, NULL);
 471 }
 472
 473 static int get_stat_data(struct cache_entry *ce,
 474                          unsigned char **sha1p,
 475                          unsigned int *modep,
 476                          int cached, int match_missing)
 477 {
 478         unsigned char *sha1 = ce->sha1;
 479         unsigned int mode = ce->ce_mode;
 480
 481         if (!cached) {
 482                 static unsigned char no_sha1[20];
 483                 int changed;
 484                 struct stat st;
 485                 if (lstat(ce->name, &st) < 0) {
 486                         if (errno == ENOENT && match_missing) {
 487                                 *sha1p = sha1;
 488                                 *modep = mode;
 489                                 return 0;
 490                         }
 491                         return -1;
 492                 }
 493                 changed = ce_match_stat(ce, &st, 0);
 494                 if (changed) {
 495                         mode = ce_mode_from_stat(ce, st.st_mode);
 496                         sha1 = no_sha1;
 497                 }
 498         }
 499
 500         *sha1p = sha1;
 501         *modep = mode;
 502         return 0;
 503 }
 504
 505 static void show_new_file(struct rev_info *revs,
 506                           struct cache_entry *new,
 507                           int cached, int match_missing)
 508 {
 509         unsigned char *sha1;
 510         unsigned int mode;
 511
 512         /* New file in the index: it might actually be different in
 513          * the working copy.
 514          */
 515         if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0)
 516                 return;
 517
 518         diff_index_show_file(revs, "+", new, sha1, mode);
 519 }
 520
 521 static int show_modified(struct rev_info *revs,
 522                          struct cache_entry *old,
 523                          struct cache_entry *new,
 524                          int report_missing,
 525                          int cached, int match_missing)
 526 {
 527         unsigned int mode, oldmode;
 528         unsigned char *sha1;
 529
 530         if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0) {
 531                 if (report_missing)
 532                         diff_index_show_file(revs, "-", old,
 533                                              old->sha1, old->ce_mode);
 534                 return -1;
 535         }
 536
 537         if (revs->combine_merges && !cached &&
 538             (hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
 539                 struct combine_diff_path *p;
 540                 int pathlen = ce_namelen(new);
 541
 542                 p = xmalloc(combine_diff_path_size(2, pathlen));
 543                 p->path = (char *) &p->parent[2];
 544                 p->next = NULL;
 545                 p->len = pathlen;
 546                 memcpy(p->path, new->name, pathlen);
 547                 p->path[pathlen] = 0;
 548                 p->mode = ntohl(mode);
 549                 hashclr(p->sha1);
 550                 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
 551                 p->parent[0].status = DIFF_STATUS_MODIFIED;
 552                 p->parent[0].mode = ntohl(new->ce_mode);
 553                 hashcpy(p->parent[0].sha1, new->sha1);
 554                 p->parent[1].status = DIFF_STATUS_MODIFIED;
 555                 p->parent[1].mode = ntohl(old->ce_mode);
 556                 hashcpy(p->parent[1].sha1, old->sha1);
 557                 show_combined_diff(p, 2, revs->dense_combined_merges, revs);
 558                 free(p);
 559                 return 0;
 560         }
 561
 562         oldmode = old->ce_mode;
 563         if (mode == oldmode && !hashcmp(sha1, old->sha1) &&
 564             !revs->diffopt.find_copies_harder)
 565                 return 0;
 566
 567         mode = ntohl(mode);
 568         oldmode = ntohl(oldmode);
 569
 570         diff_change(&revs->diffopt, oldmode, mode,
 571                     old->sha1, sha1, old->name, NULL);
 572         return 0;
 573 }
 574
 575 static int diff_cache(struct rev_info *revs,
 576                       struct cache_entry **ac, int entries,
 577                       const char **pathspec,
 578                       int cached, int match_missing)
 579 {
 580         while (entries) {
 581                 struct cache_entry *ce = *ac;
 582                 int same = (entries > 1) && ce_same_name(ce, ac[1]);
 583
 584                 if (revs->diffopt.quiet && revs->diffopt.has_changes)
 585                         break;
 586
 587                 if (!ce_path_match(ce, pathspec))
 588                         goto skip_entry;
 589
 590                 switch (ce_stage(ce)) {
 591                 case 0:
 592                         /* No stage 1 entry? That means it's a new file */
 593                         if (!same) {
 594                                 show_new_file(revs, ce, cached, match_missing);
 595                                 break;
 596                         }
 597                         /* Show difference between old and new */
 598                         show_modified(revs, ac[1], ce, 1,
 599                                       cached, match_missing);
 600                         break;
 601                 case 1:
 602                         /* No stage 3 (merge) entry?
 603                          * That means it's been deleted.
 604                          */
 605                         if (!same) {
 606                                 diff_index_show_file(revs, "-", ce,
 607                                                      ce->sha1, ce->ce_mode);
 608                                 break;
 609                         }
 610                         /* We come here with ce pointing at stage 1
 611                          * (original tree) and ac[1] pointing at stage
 612                          * 3 (unmerged).  show-modified with
 613                          * report-missing set to false does not say the
 614                          * file is deleted but reports true if work
 615                          * tree does not have it, in which case we
 616                          * fall through to report the unmerged state.
 617                          * Otherwise, we show the differences between
 618                          * the original tree and the work tree.
 619                          */
 620                         if (!cached &&
 621                             !show_modified(revs, ce, ac[1], 0,
 622                                            cached, match_missing))
 623                                 break;
 624                         diff_unmerge(&revs->diffopt, ce->name,
 625                                      ntohl(ce->ce_mode), ce->sha1);
 626                         break;
 627                 case 3:
 628                         diff_unmerge(&revs->diffopt, ce->name,
 629                                      0, null_sha1);
 630                         break;
 631
 632                 default:
 633                         die("impossible cache entry stage");
 634                 }
 635
 636 skip_entry:
 637                 /*
 638                  * Ignore all the different stages for this file,
 639                  * we've handled the relevant cases now.
 640                  */
 641                 do {
 642                         ac++;
 643                         entries--;
 644                 } while (entries && ce_same_name(ce, ac[0]));
 645         }
 646         return 0;
 647 }
 648
 649 /*
 650  * This turns all merge entries into "stage 3". That guarantees that
 651  * when we read in the new tree (into "stage 1"), we won't lose sight
 652  * of the fact that we had unmerged entries.
 653  */
 654 static void mark_merge_entries(void)
 655 {
 656         int i;
 657         for (i = 0; i < active_nr; i++) {
 658                 struct cache_entry *ce = active_cache[i];
 659                 if (!ce_stage(ce))
 660                         continue;
 661                 ce->ce_flags |= htons(CE_STAGEMASK);
 662         }
 663 }
 664
 665 int run_diff_index(struct rev_info *revs, int cached)
 666 {
 667         int ret;
 668         struct object *ent;
 669         struct tree *tree;
 670         const char *tree_name;
 671         int match_missing = 0;
 672
 673         /*
 674          * Backward compatibility wart - "diff-index -m" does
 675          * not mean "do not ignore merges", but totally different.
 676          */
 677         if (!revs->ignore_merges)
 678                 match_missing = 1;
 679
 680         mark_merge_entries();
 681
 682         ent = revs->pending.objects[0].item;
 683         tree_name = revs->pending.objects[0].name;
 684         tree = parse_tree_indirect(ent->sha1);
 685         if (!tree)
 686                 return error("bad tree object %s", tree_name);
 687         if (read_tree(tree, 1, revs->prune_data))
 688                 return error("unable to read tree object %s", tree_name);
 689         ret = diff_cache(revs, active_cache, active_nr, revs->prune_data,
 690                          cached, match_missing);
 691         diffcore_std(&revs->diffopt);
 692         diff_flush(&revs->diffopt);
 693         return ret;
 694 }
 695
 696 int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
 697 {
 698         struct tree *tree;
 699         struct rev_info revs;
 700         int i;
 701         struct cache_entry **dst;
 702         struct cache_entry *last = NULL;
 703
 704         /*
 705          * This is used by git-blame to run diff-cache internally;
 706          * it potentially needs to repeatedly run this, so we will
 707          * start by removing the higher order entries the last round
 708          * left behind.
 709          */
 710         dst = active_cache;
 711         for (i = 0; i < active_nr; i++) {
 712                 struct cache_entry *ce = active_cache[i];
 713                 if (ce_stage(ce)) {
 714                         if (last && !strcmp(ce->name, last->name))
 715                                 continue;
 716                         cache_tree_invalidate_path(active_cache_tree,
 717                                                    ce->name);
 718                         last = ce;
 719                         ce->ce_mode = 0;
 720                         ce->ce_flags &= ~htons(CE_STAGEMASK);
 721                 }
 722                 *dst++ = ce;
 723         }
 724         active_nr = dst - active_cache;
 725
 726         init_revisions(&revs, NULL);
 727         revs.prune_data = opt->paths;
 728         tree = parse_tree_indirect(tree_sha1);
 729         if (!tree)
 730                 die("bad tree object %s", sha1_to_hex(tree_sha1));
 731         if (read_tree(tree, 1, opt->paths))
 732                 return error("unable to read tree %s", sha1_to_hex(tree_sha1));
 733         return diff_cache(&revs, active_cache, active_nr, revs.prune_data,
 734                           1, 0);
 735 }