cache-tree.c

   1 #include "cache.h"
   2 #include "tree.h"
   3 #include "tree-walk.h"
   4 #include "cache-tree.h"
   5
   6 #ifndef DEBUG
   7 #define DEBUG 0
   8 #endif
   9
  10 struct cache_tree *cache_tree(void)
  11 {
  12         struct cache_tree *it = xcalloc(1, sizeof(struct cache_tree));
  13         it->entry_count = -1;
  14         return it;
  15 }
  16
  17 void cache_tree_free(struct cache_tree **it_p)
  18 {
  19         int i;
  20         struct cache_tree *it = *it_p;
  21
  22         if (!it)
  23                 return;
  24         for (i = 0; i < it->subtree_nr; i++)
  25                 if (it->down[i]) {
  26                         cache_tree_free(&it->down[i]->cache_tree);
  27                         free(it->down[i]);
  28                 }
  29         free(it->down);
  30         free(it);
  31         *it_p = NULL;
  32 }
  33
  34 static int subtree_name_cmp(const char *one, int onelen,
  35                             const char *two, int twolen)
  36 {
  37         if (onelen < twolen)
  38                 return -1;
  39         if (twolen < onelen)
  40                 return 1;
  41         return memcmp(one, two, onelen);
  42 }
  43
  44 static int subtree_pos(struct cache_tree *it, const char *path, int pathlen)
  45 {
  46         struct cache_tree_sub **down = it->down;
  47         int lo, hi;
  48         lo = 0;
  49         hi = it->subtree_nr;
  50         while (lo < hi) {
  51                 int mi = (lo + hi) / 2;
  52                 struct cache_tree_sub *mdl = down[mi];
  53                 int cmp = subtree_name_cmp(path, pathlen,
  54                                            mdl->name, mdl->namelen);
  55                 if (!cmp)
  56                         return mi;
  57                 if (cmp < 0)
  58                         hi = mi;
  59                 else
  60                         lo = mi + 1;
  61         }
  62         return -lo-1;
  63 }
  64
  65 static struct cache_tree_sub *find_subtree(struct cache_tree *it,
  66                                            const char *path,
  67                                            int pathlen,
  68                                            int create)
  69 {
  70         struct cache_tree_sub *down;
  71         int pos = subtree_pos(it, path, pathlen);
  72         if (0 <= pos)
  73                 return it->down[pos];
  74         if (!create)
  75                 return NULL;
  76
  77         pos = -pos-1;
  78         ALLOC_GROW(it->down, it->subtree_nr + 1, it->subtree_alloc);
  79         it->subtree_nr++;
  80
  81         down = xmalloc(sizeof(*down) + pathlen + 1);
  82         down->cache_tree = NULL;
  83         down->namelen = pathlen;
  84         memcpy(down->name, path, pathlen);
  85         down->name[pathlen] = 0;
  86
  87         if (pos < it->subtree_nr)
  88                 memmove(it->down + pos + 1,
  89                         it->down + pos,
  90                         sizeof(down) * (it->subtree_nr - pos - 1));
  91         it->down[pos] = down;
  92         return down;
  93 }
  94
  95 struct cache_tree_sub *cache_tree_sub(struct cache_tree *it, const char *path)
  96 {
  97         int pathlen = strlen(path);
  98         return find_subtree(it, path, pathlen, 1);
  99 }
 100
 101 void cache_tree_invalidate_path(struct cache_tree *it, const char *path)
 102 {
 103         /* a/b/c
 104          * ==> invalidate self
 105          * ==> find "a", have it invalidate "b/c"
 106          * a
 107          * ==> invalidate self
 108          * ==> if "a" exists as a subtree, remove it.
 109          */
 110         const char *slash;
 111         int namelen;
 112         struct cache_tree_sub *down;
 113
 114 #if DEBUG
 115         fprintf(stderr, "cache-tree invalidate <%s>\n", path);
 116 #endif
 117
 118         if (!it)
 119                 return;
 120         slash = strchrnul(path, '/');
 121         namelen = slash - path;
 122         it->entry_count = -1;
 123         if (!*slash) {
 124                 int pos;
 125                 pos = subtree_pos(it, path, namelen);
 126                 if (0 <= pos) {
 127                         cache_tree_free(&it->down[pos]->cache_tree);
 128                         free(it->down[pos]);
 129                         /* 0 1 2 3 4 5
 130                          *       ^     ^subtree_nr = 6
 131                          *       pos
 132                          * move 4 and 5 up one place (2 entries)
 133                          * 2 = 6 - 3 - 1 = subtree_nr - pos - 1
 134                          */
 135                         memmove(it->down+pos, it->down+pos+1,
 136                                 sizeof(struct cache_tree_sub *) *
 137                                 (it->subtree_nr - pos - 1));
 138                         it->subtree_nr--;
 139                 }
 140                 return;
 141         }
 142         down = find_subtree(it, path, namelen, 0);
 143         if (down)
 144                 cache_tree_invalidate_path(down->cache_tree, slash + 1);
 145 }
 146
 147 static int verify_cache(const struct cache_entry * const *cache,
 148                         int entries, int flags)
 149 {
 150         int i, funny;
 151         int silent = flags & WRITE_TREE_SILENT;
 152
 153         /* Verify that the tree is merged */
 154         funny = 0;
 155         for (i = 0; i < entries; i++) {
 156                 const struct cache_entry *ce = cache[i];
 157                 if (ce_stage(ce)) {
 158                         if (silent)
 159                                 return -1;
 160                         if (10 < ++funny) {
 161                                 fprintf(stderr, "...\n");
 162                                 break;
 163                         }
 164                         fprintf(stderr, "%s: unmerged (%s)\n",
 165                                 ce->name, sha1_to_hex(ce->sha1));
 166                 }
 167         }
 168         if (funny)
 169                 return -1;
 170
 171         /* Also verify that the cache does not have path and path/file
 172          * at the same time.  At this point we know the cache has only
 173          * stage 0 entries.
 174          */
 175         funny = 0;
 176         for (i = 0; i < entries - 1; i++) {
 177                 /* path/file always comes after path because of the way
 178                  * the cache is sorted.  Also path can appear only once,
 179                  * which means conflicting one would immediately follow.
 180                  */
 181                 const char *this_name = cache[i]->name;
 182                 const char *next_name = cache[i+1]->name;
 183                 int this_len = strlen(this_name);
 184                 if (this_len < strlen(next_name) &&
 185                     strncmp(this_name, next_name, this_len) == 0 &&
 186                     next_name[this_len] == '/') {
 187                         if (10 < ++funny) {
 188                                 fprintf(stderr, "...\n");
 189                                 break;
 190                         }
 191                         fprintf(stderr, "You have both %s and %s\n",
 192                                 this_name, next_name);
 193                 }
 194         }
 195         if (funny)
 196                 return -1;
 197         return 0;
 198 }
 199
 200 static void discard_unused_subtrees(struct cache_tree *it)
 201 {
 202         struct cache_tree_sub **down = it->down;
 203         int nr = it->subtree_nr;
 204         int dst, src;
 205         for (dst = src = 0; src < nr; src++) {
 206                 struct cache_tree_sub *s = down[src];
 207                 if (s->used)
 208                         down[dst++] = s;
 209                 else {
 210                         cache_tree_free(&s->cache_tree);
 211                         free(s);
 212                         it->subtree_nr--;
 213                 }
 214         }
 215 }
 216
 217 int cache_tree_fully_valid(struct cache_tree *it)
 218 {
 219         int i;
 220         if (!it)
 221                 return 0;
 222         if (it->entry_count < 0 || !has_sha1_file(it->sha1))
 223                 return 0;
 224         for (i = 0; i < it->subtree_nr; i++) {
 225                 if (!cache_tree_fully_valid(it->down[i]->cache_tree))
 226                         return 0;
 227         }
 228         return 1;
 229 }
 230
 231 static int update_one(struct cache_tree *it,
 232                       const struct cache_entry * const *cache,
 233                       int entries,
 234                       const char *base,
 235                       int baselen,
 236                       int *skip_count,
 237                       int flags)
 238 {
 239         struct strbuf buffer;
 240         int missing_ok = flags & WRITE_TREE_MISSING_OK;
 241         int dryrun = flags & WRITE_TREE_DRY_RUN;
 242         int to_invalidate = 0;
 243         int i;
 244
 245         *skip_count = 0;
 246
 247         if (0 <= it->entry_count && has_sha1_file(it->sha1))
 248                 return it->entry_count;
 249
 250         /*
 251          * We first scan for subtrees and update them; we start by
 252          * marking existing subtrees -- the ones that are unmarked
 253          * should not be in the result.
 254          */
 255         for (i = 0; i < it->subtree_nr; i++)
 256                 it->down[i]->used = 0;
 257
 258         /*
 259          * Find the subtrees and update them.
 260          */
 261         i = 0;
 262         while (i < entries) {
 263                 const struct cache_entry *ce = cache[i];
 264                 struct cache_tree_sub *sub;
 265                 const char *path, *slash;
 266                 int pathlen, sublen, subcnt, subskip;
 267
 268                 path = ce->name;
 269                 pathlen = ce_namelen(ce);
 270                 if (pathlen <= baselen || memcmp(base, path, baselen))
 271                         break; /* at the end of this level */
 272
 273                 slash = strchr(path + baselen, '/');
 274                 if (!slash) {
 275                         i++;
 276                         continue;
 277                 }
 278                 /*
 279                  * a/bbb/c (base = a/, slash = /c)
 280                  * ==>
 281                  * path+baselen = bbb/c, sublen = 3
 282                  */
 283                 sublen = slash - (path + baselen);
 284                 sub = find_subtree(it, path + baselen, sublen, 1);
 285                 if (!sub->cache_tree)
 286                         sub->cache_tree = cache_tree();
 287                 subcnt = update_one(sub->cache_tree,
 288                                     cache + i, entries - i,
 289                                     path,
 290                                     baselen + sublen + 1,
 291                                     &subskip,
 292                                     flags);
 293                 if (subcnt < 0)
 294                         return subcnt;
 295                 i += subcnt;
 296                 sub->count = subcnt; /* to be used in the next loop */
 297                 *skip_count += subskip;
 298                 sub->used = 1;
 299         }
 300
 301         discard_unused_subtrees(it);
 302
 303         /*
 304          * Then write out the tree object for this level.
 305          */
 306         strbuf_init(&buffer, 8192);
 307
 308         i = 0;
 309         while (i < entries) {
 310                 const struct cache_entry *ce = cache[i];
 311                 struct cache_tree_sub *sub;
 312                 const char *path, *slash;
 313                 int pathlen, entlen;
 314                 const unsigned char *sha1;
 315                 unsigned mode;
 316
 317                 path = ce->name;
 318                 pathlen = ce_namelen(ce);
 319                 if (pathlen <= baselen || memcmp(base, path, baselen))
 320                         break; /* at the end of this level */
 321
 322                 slash = strchr(path + baselen, '/');
 323                 if (slash) {
 324                         entlen = slash - (path + baselen);
 325                         sub = find_subtree(it, path + baselen, entlen, 0);
 326                         if (!sub)
 327                                 die("cache-tree.c: '%.*s' in '%s' not found",
 328                                     entlen, path + baselen, path);
 329                         i += sub->count;
 330                         sha1 = sub->cache_tree->sha1;
 331                         mode = S_IFDIR;
 332                         if (sub->cache_tree->entry_count < 0)
 333                                 to_invalidate = 1;
 334                 }
 335                 else {
 336                         sha1 = ce->sha1;
 337                         mode = ce->ce_mode;
 338                         entlen = pathlen - baselen;
 339                         i++;
 340                 }
 341                 if (mode != S_IFGITLINK && !missing_ok && !has_sha1_file(sha1)) {
 342                         strbuf_release(&buffer);
 343                         return error("invalid object %06o %s for '%.*s'",
 344                                 mode, sha1_to_hex(sha1), entlen+baselen, path);
 345                 }
 346
 347                 /*
 348                  * CE_REMOVE entries are removed before the index is
 349                  * written to disk. Skip them to remain consistent
 350                  * with the future on-disk index.
 351                  */
 352                 if (ce->ce_flags & CE_REMOVE) {
 353                         *skip_count = *skip_count + 1;
 354                         continue;
 355                 }
 356
 357                 /*
 358                  * CE_INTENT_TO_ADD entries exist on on-disk index but
 359                  * they are not part of generated trees. Invalidate up
 360                  * to root to force cache-tree users to read elsewhere.
 361                  */
 362                 if (ce->ce_flags & CE_INTENT_TO_ADD) {
 363                         to_invalidate = 1;
 364                         continue;
 365                 }
 366
 367                 strbuf_grow(&buffer, entlen + 100);
 368                 strbuf_addf(&buffer, "%o %.*s%c", mode, entlen, path + baselen, '\0');
 369                 strbuf_add(&buffer, sha1, 20);
 370
 371 #if DEBUG
 372                 fprintf(stderr, "cache-tree update-one %o %.*s\n",
 373                         mode, entlen, path + baselen);
 374 #endif
 375         }
 376
 377         if (dryrun)
 378                 hash_sha1_file(buffer.buf, buffer.len, tree_type, it->sha1);
 379         else if (write_sha1_file(buffer.buf, buffer.len, tree_type, it->sha1)) {
 380                 strbuf_release(&buffer);
 381                 return -1;
 382         }
 383
 384         strbuf_release(&buffer);
 385         it->entry_count = to_invalidate ? -1 : i - *skip_count;
 386 #if DEBUG
 387         fprintf(stderr, "cache-tree update-one (%d ent, %d subtree) %s\n",
 388                 it->entry_count, it->subtree_nr,
 389                 sha1_to_hex(it->sha1));
 390 #endif
 391         return i;
 392 }
 393
 394 int cache_tree_update(struct cache_tree *it,
 395                       const struct cache_entry * const *cache,
 396                       int entries,
 397                       int flags)
 398 {
 399         int i, skip;
 400         i = verify_cache(cache, entries, flags);
 401         if (i)
 402                 return i;
 403         i = update_one(it, cache, entries, "", 0, &skip, flags);
 404         if (i < 0)
 405                 return i;
 406         return 0;
 407 }
 408
 409 static void write_one(struct strbuf *buffer, struct cache_tree *it,
 410                       const char *path, int pathlen)
 411 {
 412         int i;
 413
 414         /* One "cache-tree" entry consists of the following:
 415          * path (NUL terminated)
 416          * entry_count, subtree_nr ("%d %d\n")
 417          * tree-sha1 (missing if invalid)
 418          * subtree_nr "cache-tree" entries for subtrees.
 419          */
 420         strbuf_grow(buffer, pathlen + 100);
 421         strbuf_add(buffer, path, pathlen);
 422         strbuf_addf(buffer, "%c%d %d\n", 0, it->entry_count, it->subtree_nr);
 423
 424 #if DEBUG
 425         if (0 <= it->entry_count)
 426                 fprintf(stderr, "cache-tree <%.*s> (%d ent, %d subtree) %s\n",
 427                         pathlen, path, it->entry_count, it->subtree_nr,
 428                         sha1_to_hex(it->sha1));
 429         else
 430                 fprintf(stderr, "cache-tree <%.*s> (%d subtree) invalid\n",
 431                         pathlen, path, it->subtree_nr);
 432 #endif
 433
 434         if (0 <= it->entry_count) {
 435                 strbuf_add(buffer, it->sha1, 20);
 436         }
 437         for (i = 0; i < it->subtree_nr; i++) {
 438                 struct cache_tree_sub *down = it->down[i];
 439                 if (i) {
 440                         struct cache_tree_sub *prev = it->down[i-1];
 441                         if (subtree_name_cmp(down->name, down->namelen,
 442                                              prev->name, prev->namelen) <= 0)
 443                                 die("fatal - unsorted cache subtree");
 444                 }
 445                 write_one(buffer, down->cache_tree, down->name, down->namelen);
 446         }
 447 }
 448
 449 void cache_tree_write(struct strbuf *sb, struct cache_tree *root)
 450 {
 451         write_one(sb, root, "", 0);
 452 }
 453
 454 static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
 455 {
 456         const char *buf = *buffer;
 457         unsigned long size = *size_p;
 458         const char *cp;
 459         char *ep;
 460         struct cache_tree *it;
 461         int i, subtree_nr;
 462
 463         it = NULL;
 464         /* skip name, but make sure name exists */
 465         while (size && *buf) {
 466                 size--;
 467                 buf++;
 468         }
 469         if (!size)
 470                 goto free_return;
 471         buf++; size--;
 472         it = cache_tree();
 473
 474         cp = buf;
 475         it->entry_count = strtol(cp, &ep, 10);
 476         if (cp == ep)
 477                 goto free_return;
 478         cp = ep;
 479         subtree_nr = strtol(cp, &ep, 10);
 480         if (cp == ep)
 481                 goto free_return;
 482         while (size && *buf && *buf != '\n') {
 483                 size--;
 484                 buf++;
 485         }
 486         if (!size)
 487                 goto free_return;
 488         buf++; size--;
 489         if (0 <= it->entry_count) {
 490                 if (size < 20)
 491                         goto free_return;
 492                 hashcpy(it->sha1, (const unsigned char*)buf);
 493                 buf += 20;
 494                 size -= 20;
 495         }
 496
 497 #if DEBUG
 498         if (0 <= it->entry_count)
 499                 fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
 500                         *buffer, it->entry_count, subtree_nr,
 501                         sha1_to_hex(it->sha1));
 502         else
 503                 fprintf(stderr, "cache-tree <%s> (%d subtrees) invalid\n",
 504                         *buffer, subtree_nr);
 505 #endif
 506
 507         /*
 508          * Just a heuristic -- we do not add directories that often but
 509          * we do not want to have to extend it immediately when we do,
 510          * hence +2.
 511          */
 512         it->subtree_alloc = subtree_nr + 2;
 513         it->down = xcalloc(it->subtree_alloc, sizeof(struct cache_tree_sub *));
 514         for (i = 0; i < subtree_nr; i++) {
 515                 /* read each subtree */
 516                 struct cache_tree *sub;
 517                 struct cache_tree_sub *subtree;
 518                 const char *name = buf;
 519
 520                 sub = read_one(&buf, &size);
 521                 if (!sub)
 522                         goto free_return;
 523                 subtree = cache_tree_sub(it, name);
 524                 subtree->cache_tree = sub;
 525         }
 526         if (subtree_nr != it->subtree_nr)
 527                 die("cache-tree: internal error");
 528         *buffer = buf;
 529         *size_p = size;
 530         return it;
 531
 532  free_return:
 533         cache_tree_free(&it);
 534         return NULL;
 535 }
 536
 537 struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
 538 {
 539         if (buffer[0])
 540                 return NULL; /* not the whole tree */
 541         return read_one(&buffer, &size);
 542 }
 543
 544 static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
 545 {
 546         if (!it)
 547                 return NULL;
 548         while (*path) {
 549                 const char *slash;
 550                 struct cache_tree_sub *sub;
 551
 552                 slash = strchrnul(path, '/');
 553                 /*
 554                  * Between path and slash is the name of the subtree
 555                  * to look for.
 556                  */
 557                 sub = find_subtree(it, path, slash - path, 0);
 558                 if (!sub)
 559                         return NULL;
 560                 it = sub->cache_tree;
 561
 562                 path = slash;
 563                 while (*path == '/')
 564                         path++;
 565         }
 566         return it;
 567 }
 568
 569 int write_cache_as_tree(unsigned char *sha1, int flags, const char *prefix)
 570 {
 571         int entries, was_valid, newfd;
 572         struct lock_file *lock_file;
 573
 574         /*
 575          * We can't free this memory, it becomes part of a linked list
 576          * parsed atexit()
 577          */
 578         lock_file = xcalloc(1, sizeof(struct lock_file));
 579
 580         newfd = hold_locked_index(lock_file, 1);
 581
 582         entries = read_cache();
 583         if (entries < 0)
 584                 return WRITE_TREE_UNREADABLE_INDEX;
 585         if (flags & WRITE_TREE_IGNORE_CACHE_TREE)
 586                 cache_tree_free(&(active_cache_tree));
 587
 588         if (!active_cache_tree)
 589                 active_cache_tree = cache_tree();
 590
 591         was_valid = cache_tree_fully_valid(active_cache_tree);
 592         if (!was_valid) {
 593                 if (cache_tree_update(active_cache_tree,
 594                                       (const struct cache_entry * const *)active_cache,
 595                                       active_nr, flags) < 0)
 596                         return WRITE_TREE_UNMERGED_INDEX;
 597                 if (0 <= newfd) {
 598                         if (!write_locked_index(&the_index, lock_file, COMMIT_LOCK))
 599                                 newfd = -1;
 600                 }
 601                 /* Not being able to write is fine -- we are only interested
 602                  * in updating the cache-tree part, and if the next caller
 603                  * ends up using the old index with unupdated cache-tree part
 604                  * it misses the work we did here, but that is just a
 605                  * performance penalty and not a big deal.
 606                  */
 607         }
 608
 609         if (prefix) {
 610                 struct cache_tree *subtree =
 611                         cache_tree_find(active_cache_tree, prefix);
 612                 if (!subtree)
 613                         return WRITE_TREE_PREFIX_ERROR;
 614                 hashcpy(sha1, subtree->sha1);
 615         }
 616         else
 617                 hashcpy(sha1, active_cache_tree->sha1);
 618
 619         if (0 <= newfd)
 620                 rollback_lock_file(lock_file);
 621
 622         return 0;
 623 }
 624
 625 static void prime_cache_tree_rec(struct cache_tree *it, struct tree *tree)
 626 {
 627         struct tree_desc desc;
 628         struct name_entry entry;
 629         int cnt;
 630
 631         hashcpy(it->sha1, tree->object.sha1);
 632         init_tree_desc(&desc, tree->buffer, tree->size);
 633         cnt = 0;
 634         while (tree_entry(&desc, &entry)) {
 635                 if (!S_ISDIR(entry.mode))
 636                         cnt++;
 637                 else {
 638                         struct cache_tree_sub *sub;
 639                         struct tree *subtree = lookup_tree(entry.sha1);
 640                         if (!subtree->object.parsed)
 641                                 parse_tree(subtree);
 642                         sub = cache_tree_sub(it, entry.path);
 643                         sub->cache_tree = cache_tree();
 644                         prime_cache_tree_rec(sub->cache_tree, subtree);
 645                         cnt += sub->cache_tree->entry_count;
 646                 }
 647         }
 648         it->entry_count = cnt;
 649 }
 650
 651 void prime_cache_tree(struct cache_tree **it, struct tree *tree)
 652 {
 653         cache_tree_free(it);
 654         *it = cache_tree();
 655         prime_cache_tree_rec(*it, tree);
 656 }
 657
 658 /*
 659  * find the cache_tree that corresponds to the current level without
 660  * exploding the full path into textual form.  The root of the
 661  * cache tree is given as "root", and our current level is "info".
 662  * (1) When at root level, info->prev is NULL, so it is "root" itself.
 663  * (2) Otherwise, find the cache_tree that corresponds to one level
 664  *     above us, and find ourselves in there.
 665  */
 666 static struct cache_tree *find_cache_tree_from_traversal(struct cache_tree *root,
 667                                                          struct traverse_info *info)
 668 {
 669         struct cache_tree *our_parent;
 670
 671         if (!info->prev)
 672                 return root;
 673         our_parent = find_cache_tree_from_traversal(root, info->prev);
 674         return cache_tree_find(our_parent, info->name.path);
 675 }
 676
 677 int cache_tree_matches_traversal(struct cache_tree *root,
 678                                  struct name_entry *ent,
 679                                  struct traverse_info *info)
 680 {
 681         struct cache_tree *it;
 682
 683         it = find_cache_tree_from_traversal(root, info);
 684         it = cache_tree_find(it, ent->path);
 685         if (it && it->entry_count > 0 && !hashcmp(ent->sha1, it->sha1))
 686                 return it->entry_count;
 687         return 0;
 688 }
 689
 690 int update_main_cache_tree(int flags)
 691 {
 692         if (!the_index.cache_tree)
 693                 the_index.cache_tree = cache_tree();
 694         return cache_tree_update(the_index.cache_tree,
 695                                  (const struct cache_entry * const *)the_index.cache,
 696                                  the_index.cache_nr, flags);
 697 }