read-tree.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  */
   6 #define DBRT_DEBUG 1
   7
   8 #include "cache.h"
   9
  10 #include "object.h"
  11 #include "tree.h"
  12 #include "cache-tree.h"
  13 #include <sys/time.h>
  14 #include <signal.h>
  15
  16 static int reset = 0;
  17 static int merge = 0;
  18 static int update = 0;
  19 static int index_only = 0;
  20 static int nontrivial_merge = 0;
  21 static int trivial_merges_only = 0;
  22 static int aggressive = 0;
  23 static int verbose_update = 0;
  24 static volatile int progress_update = 0;
  25 static const char *prefix = NULL;
  26
  27 static int head_idx = -1;
  28 static int merge_size = 0;
  29
  30 static struct object_list *trees = NULL;
  31
  32 static struct cache_entry df_conflict_entry = {
  33 };
  34
  35 static struct tree_entry_list df_conflict_list = {
  36         .name = NULL,
  37         .next = &df_conflict_list
  38 };
  39
  40 typedef int (*merge_fn_t)(struct cache_entry **src);
  41
  42 static int entcmp(char *name1, int dir1, char *name2, int dir2)
  43 {
  44         int len1 = strlen(name1);
  45         int len2 = strlen(name2);
  46         int len = len1 < len2 ? len1 : len2;
  47         int ret = memcmp(name1, name2, len);
  48         unsigned char c1, c2;
  49         if (ret)
  50                 return ret;
  51         c1 = name1[len];
  52         c2 = name2[len];
  53         if (!c1 && dir1)
  54                 c1 = '/';
  55         if (!c2 && dir2)
  56                 c2 = '/';
  57         ret = (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
  58         if (c1 && c2 && !ret)
  59                 ret = len1 - len2;
  60         return ret;
  61 }
  62
  63 static int unpack_trees_rec(struct tree_entry_list **posns, int len,
  64                             const char *base, merge_fn_t fn, int *indpos)
  65 {
  66         int baselen = strlen(base);
  67         int src_size = len + 1;
  68         do {
  69                 int i;
  70                 char *first;
  71                 int firstdir = 0;
  72                 int pathlen;
  73                 unsigned ce_size;
  74                 struct tree_entry_list **subposns;
  75                 struct cache_entry **src;
  76                 int any_files = 0;
  77                 int any_dirs = 0;
  78                 char *cache_name;
  79                 int ce_stage;
  80
  81                 /* Find the first name in the input. */
  82
  83                 first = NULL;
  84                 cache_name = NULL;
  85
  86                 /* Check the cache */
  87                 if (merge && *indpos < active_nr) {
  88                         /* This is a bit tricky: */
  89                         /* If the index has a subdirectory (with
  90                          * contents) as the first name, it'll get a
  91                          * filename like "foo/bar". But that's after
  92                          * "foo", so the entry in trees will get
  93                          * handled first, at which point we'll go into
  94                          * "foo", and deal with "bar" from the index,
  95                          * because the base will be "foo/". The only
  96                          * way we can actually have "foo/bar" first of
  97                          * all the things is if the trees don't
  98                          * contain "foo" at all, in which case we'll
  99                          * handle "foo/bar" without going into the
 100                          * directory, but that's fine (and will return
 101                          * an error anyway, with the added unknown
 102                          * file case.
 103                          */
 104
 105                         cache_name = active_cache[*indpos]->name;
 106                         if (strlen(cache_name) > baselen &&
 107                             !memcmp(cache_name, base, baselen)) {
 108                                 cache_name += baselen;
 109                                 first = cache_name;
 110                         } else {
 111                                 cache_name = NULL;
 112                         }
 113                 }
 114
 115 #if DBRT_DEBUG > 1
 116                 if (first)
 117                         printf("index %s\n", first);
 118 #endif
 119                 for (i = 0; i < len; i++) {
 120                         if (!posns[i] || posns[i] == &df_conflict_list)
 121                                 continue;
 122 #if DBRT_DEBUG > 1
 123                         printf("%d %s\n", i + 1, posns[i]->name);
 124 #endif
 125                         if (!first || entcmp(first, firstdir,
 126                                              posns[i]->name,
 127                                              posns[i]->directory) > 0) {
 128                                 first = posns[i]->name;
 129                                 firstdir = posns[i]->directory;
 130                         }
 131                 }
 132                 /* No name means we're done */
 133                 if (!first)
 134                         return 0;
 135
 136                 pathlen = strlen(first);
 137                 ce_size = cache_entry_size(baselen + pathlen);
 138
 139                 src = xcalloc(src_size, sizeof(struct cache_entry *));
 140
 141                 subposns = xcalloc(len, sizeof(struct tree_list_entry *));
 142
 143                 if (cache_name && !strcmp(cache_name, first)) {
 144                         any_files = 1;
 145                         src[0] = active_cache[*indpos];
 146                         remove_cache_entry_at(*indpos);
 147                 }
 148
 149                 for (i = 0; i < len; i++) {
 150                         struct cache_entry *ce;
 151
 152                         if (!posns[i] ||
 153                             (posns[i] != &df_conflict_list &&
 154                              strcmp(first, posns[i]->name))) {
 155                                 continue;
 156                         }
 157
 158                         if (posns[i] == &df_conflict_list) {
 159                                 src[i + merge] = &df_conflict_entry;
 160                                 continue;
 161                         }
 162
 163                         if (posns[i]->directory) {
 164                                 any_dirs = 1;
 165                                 parse_tree(posns[i]->item.tree);
 166                                 subposns[i] = posns[i]->item.tree->entries;
 167                                 posns[i] = posns[i]->next;
 168                                 src[i + merge] = &df_conflict_entry;
 169                                 continue;
 170                         }
 171
 172                         if (!merge)
 173                                 ce_stage = 0;
 174                         else if (i + 1 < head_idx)
 175                                 ce_stage = 1;
 176                         else if (i + 1 > head_idx)
 177                                 ce_stage = 3;
 178                         else
 179                                 ce_stage = 2;
 180
 181                         ce = xcalloc(1, ce_size);
 182                         ce->ce_mode = create_ce_mode(posns[i]->mode);
 183                         ce->ce_flags = create_ce_flags(baselen + pathlen,
 184                                                        ce_stage);
 185                         memcpy(ce->name, base, baselen);
 186                         memcpy(ce->name + baselen, first, pathlen + 1);
 187
 188                         any_files = 1;
 189
 190                         memcpy(ce->sha1, posns[i]->item.any->sha1, 20);
 191                         src[i + merge] = ce;
 192                         subposns[i] = &df_conflict_list;
 193                         posns[i] = posns[i]->next;
 194                 }
 195                 if (any_files) {
 196                         if (merge) {
 197                                 int ret;
 198
 199 #if DBRT_DEBUG > 1
 200                                 printf("%s:\n", first);
 201                                 for (i = 0; i < src_size; i++) {
 202                                         printf(" %d ", i);
 203                                         if (src[i])
 204                                                 printf("%s\n", sha1_to_hex(src[i]->sha1));
 205                                         else
 206                                                 printf("\n");
 207                                 }
 208 #endif
 209                                 ret = fn(src);
 210
 211 #if DBRT_DEBUG > 1
 212                                 printf("Added %d entries\n", ret);
 213 #endif
 214                                 *indpos += ret;
 215                         } else {
 216                                 for (i = 0; i < src_size; i++) {
 217                                         if (src[i]) {
 218                                                 add_cache_entry(src[i], ADD_CACHE_OK_TO_ADD|ADD_CACHE_SKIP_DFCHECK);
 219                                         }
 220                                 }
 221                         }
 222                 }
 223                 if (any_dirs) {
 224                         char *newbase = xmalloc(baselen + 2 + pathlen);
 225                         memcpy(newbase, base, baselen);
 226                         memcpy(newbase + baselen, first, pathlen);
 227                         newbase[baselen + pathlen] = '/';
 228                         newbase[baselen + pathlen + 1] = '\0';
 229                         if (unpack_trees_rec(subposns, len, newbase, fn,
 230                                              indpos))
 231                                 return -1;
 232                         free(newbase);
 233                 }
 234                 free(subposns);
 235                 free(src);
 236         } while (1);
 237 }
 238
 239 static void reject_merge(struct cache_entry *ce)
 240 {
 241         die("Entry '%s' would be overwritten by merge. Cannot merge.",
 242             ce->name);
 243 }
 244
 245 /* Unlink the last component and attempt to remove leading
 246  * directories, in case this unlink is the removal of the
 247  * last entry in the directory -- empty directories are removed.
 248  */
 249 static void unlink_entry(char *name)
 250 {
 251         char *cp, *prev;
 252
 253         if (unlink(name))
 254                 return;
 255         prev = NULL;
 256         while (1) {
 257                 int status;
 258                 cp = strrchr(name, '/');
 259                 if (prev)
 260                         *prev = '/';
 261                 if (!cp)
 262                         break;
 263
 264                 *cp = 0;
 265                 status = rmdir(name);
 266                 if (status) {
 267                         *cp = '/';
 268                         break;
 269                 }
 270                 prev = cp;
 271         }
 272 }
 273
 274 static void progress_interval(int signum)
 275 {
 276         progress_update = 1;
 277 }
 278
 279 static void setup_progress_signal(void)
 280 {
 281         struct sigaction sa;
 282         struct itimerval v;
 283
 284         memset(&sa, 0, sizeof(sa));
 285         sa.sa_handler = progress_interval;
 286         sigemptyset(&sa.sa_mask);
 287         sa.sa_flags = SA_RESTART;
 288         sigaction(SIGALRM, &sa, NULL);
 289
 290         v.it_interval.tv_sec = 1;
 291         v.it_interval.tv_usec = 0;
 292         v.it_value = v.it_interval;
 293         setitimer(ITIMER_REAL, &v, NULL);
 294 }
 295
 296 static void check_updates(struct cache_entry **src, int nr)
 297 {
 298         static struct checkout state = {
 299                 .base_dir = "",
 300                 .force = 1,
 301                 .quiet = 1,
 302                 .refresh_cache = 1,
 303         };
 304         unsigned short mask = htons(CE_UPDATE);
 305         unsigned last_percent = 200, cnt = 0, total = 0;
 306
 307         if (update && verbose_update) {
 308                 for (total = cnt = 0; cnt < nr; cnt++) {
 309                         struct cache_entry *ce = src[cnt];
 310                         if (!ce->ce_mode || ce->ce_flags & mask)
 311                                 total++;
 312                 }
 313
 314                 /* Don't bother doing this for very small updates */
 315                 if (total < 250)
 316                         total = 0;
 317
 318                 if (total) {
 319                         fprintf(stderr, "Checking files out...\n");
 320                         setup_progress_signal();
 321                         progress_update = 1;
 322                 }
 323                 cnt = 0;
 324         }
 325
 326         while (nr--) {
 327                 struct cache_entry *ce = *src++;
 328
 329                 if (total) {
 330                         if (!ce->ce_mode || ce->ce_flags & mask) {
 331                                 unsigned percent;
 332                                 cnt++;
 333                                 percent = (cnt * 100) / total;
 334                                 if (percent != last_percent ||
 335                                     progress_update) {
 336                                         fprintf(stderr, "%4u%% (%u/%u) done\r",
 337                                                 percent, cnt, total);
 338                                         last_percent = percent;
 339                                 }
 340                         }
 341                 }
 342                 if (!ce->ce_mode) {
 343                         if (update)
 344                                 unlink_entry(ce->name);
 345                         continue;
 346                 }
 347                 if (ce->ce_flags & mask) {
 348                         ce->ce_flags &= ~mask;
 349                         if (update)
 350                                 checkout_entry(ce, &state, NULL);
 351                 }
 352         }
 353         if (total) {
 354                 signal(SIGALRM, SIG_IGN);
 355                 fputc('\n', stderr);
 356         }
 357 }
 358
 359 static int unpack_trees(merge_fn_t fn)
 360 {
 361         int indpos = 0;
 362         unsigned len = object_list_length(trees);
 363         struct tree_entry_list **posns;
 364         int i;
 365         struct object_list *posn = trees;
 366         merge_size = len;
 367
 368         if (len) {
 369                 posns = xmalloc(len * sizeof(struct tree_entry_list *));
 370                 for (i = 0; i < len; i++) {
 371                         posns[i] = ((struct tree *) posn->item)->entries;
 372                         posn = posn->next;
 373                 }
 374                 if (unpack_trees_rec(posns, len, prefix ? prefix : "",
 375                                      fn, &indpos))
 376                         return -1;
 377         }
 378
 379         if (trivial_merges_only && nontrivial_merge)
 380                 die("Merge requires file-level merging");
 381
 382         check_updates(active_cache, active_nr);
 383         return 0;
 384 }
 385
 386 static int list_tree(unsigned char *sha1)
 387 {
 388         struct tree *tree = parse_tree_indirect(sha1);
 389         if (!tree)
 390                 return -1;
 391         object_list_append(&tree->object, &trees);
 392         return 0;
 393 }
 394
 395 static int same(struct cache_entry *a, struct cache_entry *b)
 396 {
 397         if (!!a != !!b)
 398                 return 0;
 399         if (!a && !b)
 400                 return 1;
 401         return a->ce_mode == b->ce_mode &&
 402                 !memcmp(a->sha1, b->sha1, 20);
 403 }
 404
 405
 406 /*
 407  * When a CE gets turned into an unmerged entry, we
 408  * want it to be up-to-date
 409  */
 410 static void verify_uptodate(struct cache_entry *ce)
 411 {
 412         struct stat st;
 413
 414         if (index_only)
 415                 return;
 416
 417         if (!lstat(ce->name, &st)) {
 418                 unsigned changed = ce_match_stat(ce, &st, 1);
 419                 if (!changed)
 420                         return;
 421                 errno = 0;
 422         }
 423         if (reset) {
 424                 ce->ce_flags |= htons(CE_UPDATE);
 425                 return;
 426         }
 427         if (errno == ENOENT)
 428                 return;
 429         die("Entry '%s' not uptodate. Cannot merge.", ce->name);
 430 }
 431
 432 static void invalidate_ce_path(struct cache_entry *ce)
 433 {
 434         if (ce)
 435                 cache_tree_invalidate_path(active_cache_tree, ce->name);
 436 }
 437
 438 static int merged_entry(struct cache_entry *merge, struct cache_entry *old)
 439 {
 440         merge->ce_flags |= htons(CE_UPDATE);
 441         if (old) {
 442                 /*
 443                  * See if we can re-use the old CE directly?
 444                  * That way we get the uptodate stat info.
 445                  *
 446                  * This also removes the UPDATE flag on
 447                  * a match.
 448                  */
 449                 if (same(old, merge)) {
 450                         *merge = *old;
 451                 } else {
 452                         verify_uptodate(old);
 453                         invalidate_ce_path(old);
 454                 }
 455         }
 456         else
 457                 invalidate_ce_path(merge);
 458         merge->ce_flags &= ~htons(CE_STAGEMASK);
 459         add_cache_entry(merge, ADD_CACHE_OK_TO_ADD);
 460         return 1;
 461 }
 462
 463 static int deleted_entry(struct cache_entry *ce, struct cache_entry *old)
 464 {
 465         if (old)
 466                 verify_uptodate(old);
 467         ce->ce_mode = 0;
 468         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
 469         invalidate_ce_path(ce);
 470         return 1;
 471 }
 472
 473 static int keep_entry(struct cache_entry *ce)
 474 {
 475         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
 476         return 1;
 477 }
 478
 479 #if DBRT_DEBUG
 480 static void show_stage_entry(FILE *o,
 481                              const char *label, const struct cache_entry *ce)
 482 {
 483         if (!ce)
 484                 fprintf(o, "%s (missing)\n", label);
 485         else
 486                 fprintf(o, "%s%06o %s %d\t%s\n",
 487                         label,
 488                         ntohl(ce->ce_mode),
 489                         sha1_to_hex(ce->sha1),
 490                         ce_stage(ce),
 491                         ce->name);
 492 }
 493 #endif
 494
 495 static int threeway_merge(struct cache_entry **stages)
 496 {
 497         struct cache_entry *index;
 498         struct cache_entry *head;
 499         struct cache_entry *remote = stages[head_idx + 1];
 500         int count;
 501         int head_match = 0;
 502         int remote_match = 0;
 503
 504         int df_conflict_head = 0;
 505         int df_conflict_remote = 0;
 506
 507         int any_anc_missing = 0;
 508         int no_anc_exists = 1;
 509         int i;
 510
 511         for (i = 1; i < head_idx; i++) {
 512                 if (!stages[i])
 513                         any_anc_missing = 1;
 514                 else
 515                         no_anc_exists = 0;
 516         }
 517
 518         index = stages[0];
 519         head = stages[head_idx];
 520
 521         if (head == &df_conflict_entry) {
 522                 df_conflict_head = 1;
 523                 head = NULL;
 524         }
 525
 526         if (remote == &df_conflict_entry) {
 527                 df_conflict_remote = 1;
 528                 remote = NULL;
 529         }
 530
 531         /* First, if there's a #16 situation, note that to prevent #13
 532          * and #14.
 533          */
 534         if (!same(remote, head)) {
 535                 for (i = 1; i < head_idx; i++) {
 536                         if (same(stages[i], head)) {
 537                                 head_match = i;
 538                         }
 539                         if (same(stages[i], remote)) {
 540                                 remote_match = i;
 541                         }
 542                 }
 543         }
 544
 545         /* We start with cases where the index is allowed to match
 546          * something other than the head: #14(ALT) and #2ALT, where it
 547          * is permitted to match the result instead.
 548          */
 549         /* #14, #14ALT, #2ALT */
 550         if (remote && !df_conflict_head && head_match && !remote_match) {
 551                 if (index && !same(index, remote) && !same(index, head))
 552                         reject_merge(index);
 553                 return merged_entry(remote, index);
 554         }
 555         /*
 556          * If we have an entry in the index cache, then we want to
 557          * make sure that it matches head.
 558          */
 559         if (index && !same(index, head)) {
 560                 reject_merge(index);
 561         }
 562
 563         if (head) {
 564                 /* #5ALT, #15 */
 565                 if (same(head, remote))
 566                         return merged_entry(head, index);
 567                 /* #13, #3ALT */
 568                 if (!df_conflict_remote && remote_match && !head_match)
 569                         return merged_entry(head, index);
 570         }
 571
 572         /* #1 */
 573         if (!head && !remote && any_anc_missing)
 574                 return 0;
 575
 576         /* Under the new "aggressive" rule, we resolve mostly trivial
 577          * cases that we historically had git-merge-one-file resolve.
 578          */
 579         if (aggressive) {
 580                 int head_deleted = !head && !df_conflict_head;
 581                 int remote_deleted = !remote && !df_conflict_remote;
 582                 /*
 583                  * Deleted in both.
 584                  * Deleted in one and unchanged in the other.
 585                  */
 586                 if ((head_deleted && remote_deleted) ||
 587                     (head_deleted && remote && remote_match) ||
 588                     (remote_deleted && head && head_match)) {
 589                         if (index)
 590                                 return deleted_entry(index, index);
 591                         return 0;
 592                 }
 593                 /*
 594                  * Added in both, identically.
 595                  */
 596                 if (no_anc_exists && head && remote && same(head, remote))
 597                         return merged_entry(head, index);
 598
 599         }
 600
 601         /* Below are "no merge" cases, which require that the index be
 602          * up-to-date to avoid the files getting overwritten with
 603          * conflict resolution files.
 604          */
 605         if (index) {
 606                 verify_uptodate(index);
 607         }
 608
 609         nontrivial_merge = 1;
 610
 611         /* #2, #3, #4, #6, #7, #9, #11. */
 612         count = 0;
 613         if (!head_match || !remote_match) {
 614                 for (i = 1; i < head_idx; i++) {
 615                         if (stages[i]) {
 616                                 keep_entry(stages[i]);
 617                                 count++;
 618                                 break;
 619                         }
 620                 }
 621         }
 622 #if DBRT_DEBUG
 623         else {
 624                 fprintf(stderr, "read-tree: warning #16 detected\n");
 625                 show_stage_entry(stderr, "head   ", stages[head_match]);
 626                 show_stage_entry(stderr, "remote ", stages[remote_match]);
 627         }
 628 #endif
 629         if (head) { count += keep_entry(head); }
 630         if (remote) { count += keep_entry(remote); }
 631         return count;
 632 }
 633
 634 /*
 635  * Two-way merge.
 636  *
 637  * The rule is to "carry forward" what is in the index without losing
 638  * information across a "fast forward", favoring a successful merge
 639  * over a merge failure when it makes sense.  For details of the
 640  * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
 641  *
 642  */
 643 static int twoway_merge(struct cache_entry **src)
 644 {
 645         struct cache_entry *current = src[0];
 646         struct cache_entry *oldtree = src[1], *newtree = src[2];
 647
 648         if (merge_size != 2)
 649                 return error("Cannot do a twoway merge of %d trees",
 650                              merge_size);
 651
 652         if (current) {
 653                 if ((!oldtree && !newtree) || /* 4 and 5 */
 654                     (!oldtree && newtree &&
 655                      same(current, newtree)) || /* 6 and 7 */
 656                     (oldtree && newtree &&
 657                      same(oldtree, newtree)) || /* 14 and 15 */
 658                     (oldtree && newtree &&
 659                      !same(oldtree, newtree) && /* 18 and 19*/
 660                      same(current, newtree))) {
 661                         return keep_entry(current);
 662                 }
 663                 else if (oldtree && !newtree && same(current, oldtree)) {
 664                         /* 10 or 11 */
 665                         return deleted_entry(oldtree, current);
 666                 }
 667                 else if (oldtree && newtree &&
 668                          same(current, oldtree) && !same(current, newtree)) {
 669                         /* 20 or 21 */
 670                         return merged_entry(newtree, current);
 671                 }
 672                 else {
 673                         /* all other failures */
 674                         if (oldtree)
 675                                 reject_merge(oldtree);
 676                         if (current)
 677                                 reject_merge(current);
 678                         if (newtree)
 679                                 reject_merge(newtree);
 680                         return -1;
 681                 }
 682         }
 683         else if (newtree)
 684                 return merged_entry(newtree, current);
 685         else
 686                 return deleted_entry(oldtree, current);
 687 }
 688
 689 /*
 690  * Bind merge.
 691  *
 692  * Keep the index entries at stage0, collapse stage1 but make sure
 693  * stage0 does not have anything there.
 694  */
 695 static int bind_merge(struct cache_entry **src)
 696 {
 697         struct cache_entry *old = src[0];
 698         struct cache_entry *a = src[1];
 699
 700         if (merge_size != 1)
 701                 return error("Cannot do a bind merge of %d trees\n",
 702                              merge_size);
 703         if (a && old)
 704                 die("Entry '%s' overlaps.  Cannot bind.", a->name);
 705         if (!a)
 706                 return keep_entry(old);
 707         else
 708                 return merged_entry(a, NULL);
 709 }
 710
 711 /*
 712  * One-way merge.
 713  *
 714  * The rule is:
 715  * - take the stat information from stage0, take the data from stage1
 716  */
 717 static int oneway_merge(struct cache_entry **src)
 718 {
 719         struct cache_entry *old = src[0];
 720         struct cache_entry *a = src[1];
 721
 722         if (merge_size != 1)
 723                 return error("Cannot do a oneway merge of %d trees",
 724                              merge_size);
 725
 726         if (!a) {
 727                 invalidate_ce_path(old);
 728                 return deleted_entry(old, NULL);
 729         }
 730         if (old && same(old, a)) {
 731                 if (reset) {
 732                         struct stat st;
 733                         if (lstat(old->name, &st) ||
 734                             ce_match_stat(old, &st, 1))
 735                                 old->ce_flags |= htons(CE_UPDATE);
 736                 }
 737                 return keep_entry(old);
 738         }
 739         return merged_entry(a, NULL);
 740 }
 741
 742 static int read_cache_unmerged(void)
 743 {
 744         int i, deleted;
 745         struct cache_entry **dst;
 746
 747         read_cache();
 748         dst = active_cache;
 749         deleted = 0;
 750         for (i = 0; i < active_nr; i++) {
 751                 struct cache_entry *ce = active_cache[i];
 752                 if (ce_stage(ce)) {
 753                         deleted++;
 754                         invalidate_ce_path(ce);
 755                         continue;
 756                 }
 757                 if (deleted)
 758                         *dst = ce;
 759                 dst++;
 760         }
 761         active_nr -= deleted;
 762         return deleted;
 763 }
 764
 765 static void prime_cache_tree_rec(struct cache_tree *it, struct tree *tree)
 766 {
 767         struct tree_entry_list *ent;
 768         int cnt;
 769
 770         memcpy(it->sha1, tree->object.sha1, 20);
 771         for (cnt = 0, ent = tree->entries; ent; ent = ent->next) {
 772                 if (!ent->directory)
 773                         cnt++;
 774                 else {
 775                         struct cache_tree_sub *sub;
 776                         struct tree *subtree = (struct tree *)ent->item.tree;
 777                         if (!subtree->object.parsed)
 778                                 parse_tree(subtree);
 779                         sub = cache_tree_sub(it, ent->name);
 780                         sub->cache_tree = cache_tree();
 781                         prime_cache_tree_rec(sub->cache_tree, subtree);
 782                         cnt += sub->cache_tree->entry_count;
 783                 }
 784         }
 785         it->entry_count = cnt;
 786 }
 787
 788 static void prime_cache_tree(void)
 789 {
 790         struct tree *tree = (struct tree *)trees->item;
 791         if (!tree)
 792                 return;
 793         active_cache_tree = cache_tree();
 794         prime_cache_tree_rec(active_cache_tree, tree);
 795
 796 }
 797
 798 static const char read_tree_usage[] = "git-read-tree (<sha> | [[-m [--aggressive] | --reset | --prefix=<prefix>] [-u | -i]] <sha1> [<sha2> [<sha3>]])";
 799
 800 static struct cache_file cache_file;
 801
 802 int main(int argc, char **argv)
 803 {
 804         int i, newfd, stage = 0;
 805         unsigned char sha1[20];
 806         merge_fn_t fn = NULL;
 807
 808         setup_git_directory();
 809         git_config(git_default_config);
 810
 811         newfd = hold_index_file_for_update(&cache_file, get_index_file());
 812         if (newfd < 0)
 813                 die("unable to create new cachefile");
 814
 815         git_config(git_default_config);
 816
 817         merge = 0;
 818         reset = 0;
 819         for (i = 1; i < argc; i++) {
 820                 const char *arg = argv[i];
 821
 822                 /* "-u" means "update", meaning that a merge will update
 823                  * the working tree.
 824                  */
 825                 if (!strcmp(arg, "-u")) {
 826                         update = 1;
 827                         continue;
 828                 }
 829
 830                 if (!strcmp(arg, "-v")) {
 831                         verbose_update = 1;
 832                         continue;
 833                 }
 834
 835                 /* "-i" means "index only", meaning that a merge will
 836                  * not even look at the working tree.
 837                  */
 838                 if (!strcmp(arg, "-i")) {
 839                         index_only = 1;
 840                         continue;
 841                 }
 842
 843                 /* "--prefix=<subdirectory>/" means keep the current index
 844                  *  entries and put the entries from the tree under the
 845                  * given subdirectory.
 846                  */
 847                 if (!strncmp(arg, "--prefix=", 9)) {
 848                         if (stage || merge || prefix)
 849                                 usage(read_tree_usage);
 850                         prefix = arg + 9;
 851                         merge = 1;
 852                         stage = 1;
 853                         if (read_cache_unmerged())
 854                                 die("you need to resolve your current index first");
 855                         continue;
 856                 }
 857
 858                 /* This differs from "-m" in that we'll silently ignore unmerged entries */
 859                 if (!strcmp(arg, "--reset")) {
 860                         if (stage || merge || prefix)
 861                                 usage(read_tree_usage);
 862                         reset = 1;
 863                         merge = 1;
 864                         stage = 1;
 865                         read_cache_unmerged();
 866                         continue;
 867                 }
 868
 869                 if (!strcmp(arg, "--trivial")) {
 870                         trivial_merges_only = 1;
 871                         continue;
 872                 }
 873
 874                 if (!strcmp(arg, "--aggressive")) {
 875                         aggressive = 1;
 876                         continue;
 877                 }
 878
 879                 /* "-m" stands for "merge", meaning we start in stage 1 */
 880                 if (!strcmp(arg, "-m")) {
 881                         if (stage || merge || prefix)
 882                                 usage(read_tree_usage);
 883                         if (read_cache_unmerged())
 884                                 die("you need to resolve your current index first");
 885                         stage = 1;
 886                         merge = 1;
 887                         continue;
 888                 }
 889
 890                 /* using -u and -i at the same time makes no sense */
 891                 if (1 < index_only + update)
 892                         usage(read_tree_usage);
 893
 894                 if (get_sha1(arg, sha1))
 895                         die("Not a valid object name %s", arg);
 896                 if (list_tree(sha1) < 0)
 897                         die("failed to unpack tree object %s", arg);
 898                 stage++;
 899         }
 900         if ((update||index_only) && !merge)
 901                 usage(read_tree_usage);
 902
 903         if (prefix) {
 904                 int pfxlen = strlen(prefix);
 905                 int pos;
 906                 if (prefix[pfxlen-1] != '/')
 907                         die("prefix must end with /");
 908                 if (stage != 2)
 909                         die("binding merge takes only one tree");
 910                 pos = cache_name_pos(prefix, pfxlen);
 911                 if (0 <= pos)
 912                         die("corrupt index file");
 913                 pos = -pos-1;
 914                 if (pos < active_nr &&
 915                     !strncmp(active_cache[pos]->name, prefix, pfxlen))
 916                         die("subdirectory '%s' already exists.", prefix);
 917                 pos = cache_name_pos(prefix, pfxlen-1);
 918                 if (0 <= pos)
 919                         die("file '%.*s' already exists.", pfxlen-1, prefix);
 920         }
 921
 922         if (merge) {
 923                 if (stage < 2)
 924                         die("just how do you expect me to merge %d trees?", stage-1);
 925                 switch (stage - 1) {
 926                 case 1:
 927                         fn = prefix ? bind_merge : oneway_merge;
 928                         break;
 929                 case 2:
 930                         fn = twoway_merge;
 931                         break;
 932                 case 3:
 933                 default:
 934                         fn = threeway_merge;
 935                         cache_tree_free(&active_cache_tree);
 936                         break;
 937                 }
 938
 939                 if (stage - 1 >= 3)
 940                         head_idx = stage - 2;
 941                 else
 942                         head_idx = 1;
 943         }
 944
 945         unpack_trees(fn);
 946
 947         /*
 948          * When reading only one tree (either the most basic form,
 949          * "-m ent" or "--reset ent" form), we can obtain a fully
 950          * valid cache-tree because the index must match exactly
 951          * what came from the tree.
 952          */
 953         if (trees && trees->item && (!merge || (stage == 2))) {
 954                 cache_tree_free(&active_cache_tree);
 955                 prime_cache_tree();
 956         }
 957
 958         if (write_cache(newfd, active_cache, active_nr) ||
 959             commit_index_file(&cache_file))
 960                 die("unable to write new index file");
 961         return 0;
 962 }