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         if (it->subtree_alloc <= it->subtree_nr) {
  79                 it->subtree_alloc = alloc_nr(it->subtree_alloc);
  80                 it->down = xrealloc(it->down, it->subtree_alloc *
  81                                     sizeof(*it->down));
  82         }
  83         it->subtree_nr++;
  84
  85         down = xmalloc(sizeof(*down) + pathlen + 1);
  86         down->cache_tree = NULL;
  87         down->namelen = pathlen;
  88         memcpy(down->name, path, pathlen);
  89         down->name[pathlen] = 0;
  90
  91         if (pos < it->subtree_nr)
  92                 memmove(it->down + pos + 1,
  93                         it->down + pos,
  94                         sizeof(down) * (it->subtree_nr - pos - 1));
  95         it->down[pos] = down;
  96         return down;
  97 }
  98
  99 struct cache_tree_sub *cache_tree_sub(struct cache_tree *it, const char *path)
 100 {
 101         int pathlen = strlen(path);
 102         return find_subtree(it, path, pathlen, 1);
 103 }
 104
 105 void cache_tree_invalidate_path(struct cache_tree *it, const char *path)
 106 {
 107         /* a/b/c
 108          * ==> invalidate self
 109          * ==> find "a", have it invalidate "b/c"
 110          * a
 111          * ==> invalidate self
 112          * ==> if "a" exists as a subtree, remove it.
 113          */
 114         const char *slash;
 115         int namelen;
 116         struct cache_tree_sub *down;
 117
 118 #if DEBUG
 119         fprintf(stderr, "cache-tree invalidate <%s>\n", path);
 120 #endif
 121
 122         if (!it)
 123                 return;
 124         slash = strchr(path, '/');
 125         it->entry_count = -1;
 126         if (!slash) {
 127                 int pos;
 128                 namelen = strlen(path);
 129                 pos = subtree_pos(it, path, namelen);
 130                 if (0 <= pos) {
 131                         cache_tree_free(&it->down[pos]->cache_tree);
 132                         free(it->down[pos]);
 133                         /* 0 1 2 3 4 5
 134                          *       ^     ^subtree_nr = 6
 135                          *       pos
 136                          * move 4 and 5 up one place (2 entries)
 137                          * 2 = 6 - 3 - 1 = subtree_nr - pos - 1
 138                          */
 139                         memmove(it->down+pos, it->down+pos+1,
 140                                 sizeof(struct cache_tree_sub *) *
 141                                 (it->subtree_nr - pos - 1));
 142                         it->subtree_nr--;
 143                 }
 144                 return;
 145         }
 146         namelen = slash - path;
 147         down = find_subtree(it, path, namelen, 0);
 148         if (down)
 149                 cache_tree_invalidate_path(down->cache_tree, slash + 1);
 150 }
 151
 152 static int verify_cache(const struct cache_entry * const *cache,
 153                         int entries, int flags)
 154 {
 155         int i, funny;
 156         int silent = flags & WRITE_TREE_SILENT;
 157
 158         /* Verify that the tree is merged */
 159         funny = 0;
 160         for (i = 0; i < entries; i++) {
 161                 const struct cache_entry *ce = cache[i];
 162                 if (ce_stage(ce)) {
 163                         if (silent)
 164                                 return -1;
 165                         if (10 < ++funny) {
 166                                 fprintf(stderr, "...\n");
 167                                 break;
 168                         }
 169                         fprintf(stderr, "%s: unmerged (%s)\n",
 170                                 ce->name, sha1_to_hex(ce->sha1));
 171                 }
 172         }
 173         if (funny)
 174                 return -1;
 175
 176         /* Also verify that the cache does not have path and path/file
 177          * at the same time.  At this point we know the cache has only
 178          * stage 0 entries.
 179          */
 180         funny = 0;
 181         for (i = 0; i < entries - 1; i++) {
 182                 /* path/file always comes after path because of the way
 183                  * the cache is sorted.  Also path can appear only once,
 184                  * which means conflicting one would immediately follow.
 185                  */
 186                 const char *this_name = cache[i]->name;
 187                 const char *next_name = cache[i+1]->name;
 188                 int this_len = strlen(this_name);
 189                 if (this_len < strlen(next_name) &&
 190                     strncmp(this_name, next_name, this_len) == 0 &&
 191                     next_name[this_len] == '/') {
 192                         if (10 < ++funny) {
 193                                 fprintf(stderr, "...\n");
 194                                 break;
 195                         }
 196                         fprintf(stderr, "You have both %s and %s\n",
 197                                 this_name, next_name);
 198                 }
 199         }
 200         if (funny)
 201                 return -1;
 202         return 0;
 203 }
 204
 205 static void discard_unused_subtrees(struct cache_tree *it)
 206 {
 207         struct cache_tree_sub **down = it->down;
 208         int nr = it->subtree_nr;
 209         int dst, src;
 210         for (dst = src = 0; src < nr; src++) {
 211                 struct cache_tree_sub *s = down[src];
 212                 if (s->used)
 213                         down[dst++] = s;
 214                 else {
 215                         cache_tree_free(&s->cache_tree);
 216                         free(s);
 217                         it->subtree_nr--;
 218                 }
 219         }
 220 }
 221
 222 int cache_tree_fully_valid(struct cache_tree *it)
 223 {
 224         int i;
 225         if (!it)
 226                 return 0;
 227         if (it->entry_count < 0 || !has_sha1_file(it->sha1))
 228                 return 0;
 229         for (i = 0; i < it->subtree_nr; i++) {
 230                 if (!cache_tree_fully_valid(it->down[i]->cache_tree))
 231                         return 0;
 232         }
 233         return 1;
 234 }
 235
 236 static int update_one(struct cache_tree *it,
 237                       const struct cache_entry * const *cache,
 238                       int entries,
 239                       const char *base,
 240                       int baselen,
 241                       int *skip_count,
 242                       int flags)
 243 {
 244         struct strbuf buffer;
 245         int missing_ok = flags & WRITE_TREE_MISSING_OK;
 246         int dryrun = flags & WRITE_TREE_DRY_RUN;
 247         int to_invalidate = 0;
 248         int i;
 249
 250         *skip_count = 0;
 251
 252         if (0 <= it->entry_count && has_sha1_file(it->sha1))
 253                 return it->entry_count;
 254
 255         /*
 256          * We first scan for subtrees and update them; we start by
 257          * marking existing subtrees -- the ones that are unmarked
 258          * should not be in the result.
 259          */
 260         for (i = 0; i < it->subtree_nr; i++)
 261                 it->down[i]->used = 0;
 262
 263         /*
 264          * Find the subtrees and update them.
 265          */
 266         i = 0;
 267         while (i < entries) {
 268                 const struct cache_entry *ce = cache[i];
 269                 struct cache_tree_sub *sub;
 270                 const char *path, *slash;
 271                 int pathlen, sublen, subcnt, subskip;
 272
 273                 path = ce->name;
 274                 pathlen = ce_namelen(ce);
 275                 if (pathlen <= baselen || memcmp(base, path, baselen))
 276                         break; /* at the end of this level */
 277
 278                 slash = strchr(path + baselen, '/');
 279                 if (!slash) {
 280                         i++;
 281                         continue;
 282                 }
 283                 /*
 284                  * a/bbb/c (base = a/, slash = /c)
 285                  * ==>
 286                  * path+baselen = bbb/c, sublen = 3
 287                  */
 288                 sublen = slash - (path + baselen);
 289                 sub = find_subtree(it, path + baselen, sublen, 1);
 290                 if (!sub->cache_tree)
 291                         sub->cache_tree = cache_tree();
 292                 subcnt = update_one(sub->cache_tree,
 293                                     cache + i, entries - i,
 294                                     path,
 295                                     baselen + sublen + 1,
 296                                     &subskip,
 297                                     flags);
 298                 if (subcnt < 0)
 299                         return subcnt;
 300                 i += subcnt;
 301                 sub->count = subcnt; /* to be used in the next loop */
 302                 *skip_count += subskip;
 303                 sub->used = 1;
 304         }
 305
 306         discard_unused_subtrees(it);
 307
 308         /*
 309          * Then write out the tree object for this level.
 310          */
 311         strbuf_init(&buffer, 8192);
 312
 313         i = 0;
 314         while (i < entries) {
 315                 const struct cache_entry *ce = cache[i];
 316                 struct cache_tree_sub *sub;
 317                 const char *path, *slash;
 318                 int pathlen, entlen;
 319                 const unsigned char *sha1;
 320                 unsigned mode;
 321
 322                 path = ce->name;
 323                 pathlen = ce_namelen(ce);
 324                 if (pathlen <= baselen || memcmp(base, path, baselen))
 325                         break; /* at the end of this level */
 326
 327                 slash = strchr(path + baselen, '/');
 328                 if (slash) {
 329                         entlen = slash - (path + baselen);
 330                         sub = find_subtree(it, path + baselen, entlen, 0);
 331                         if (!sub)
 332                                 die("cache-tree.c: '%.*s' in '%s' not found",
 333                                     entlen, path + baselen, path);
 334                         i += sub->count;
 335                         sha1 = sub->cache_tree->sha1;
 336                         mode = S_IFDIR;
 337                         if (sub->cache_tree->entry_count < 0)
 338                                 to_invalidate = 1;
 339                 }
 340                 else {
 341                         sha1 = ce->sha1;
 342                         mode = ce->ce_mode;
 343                         entlen = pathlen - baselen;
 344                         i++;
 345                 }
 346                 if (mode != S_IFGITLINK && !missing_ok && !has_sha1_file(sha1)) {
 347                         strbuf_release(&buffer);
 348                         return error("invalid object %06o %s for '%.*s'",
 349                                 mode, sha1_to_hex(sha1), entlen+baselen, path);
 350                 }
 351
 352                 /*
 353                  * CE_REMOVE entries are removed before the index is
 354                  * written to disk. Skip them to remain consistent
 355                  * with the future on-disk index.
 356                  */
 357                 if (ce->ce_flags & CE_REMOVE) {
 358                         *skip_count = *skip_count + 1;
 359                         continue;
 360                 }
 361
 362                 /*
 363                  * CE_INTENT_TO_ADD entries exist on on-disk index but
 364                  * they are not part of generated trees. Invalidate up
 365                  * to root to force cache-tree users to read elsewhere.
 366                  */
 367                 if (ce->ce_flags & CE_INTENT_TO_ADD) {
 368                         to_invalidate = 1;
 369                         continue;
 370                 }
 371
 372                 strbuf_grow(&buffer, entlen + 100);
 373                 strbuf_addf(&buffer, "%o %.*s%c", mode, entlen, path + baselen, '\0');
 374                 strbuf_add(&buffer, sha1, 20);
 375
 376 #if DEBUG
 377                 fprintf(stderr, "cache-tree update-one %o %.*s\n",
 378                         mode, entlen, path + baselen);
 379 #endif
 380         }
 381
 382         if (dryrun)
 383                 hash_sha1_file(buffer.buf, buffer.len, tree_type, it->sha1);
 384         else if (write_sha1_file(buffer.buf, buffer.len, tree_type, it->sha1)) {
 385                 strbuf_release(&buffer);
 386                 return -1;
 387         }
 388
 389         strbuf_release(&buffer);
 390         it->entry_count = to_invalidate ? -1 : i - *skip_count;
 391 #if DEBUG
 392         fprintf(stderr, "cache-tree update-one (%d ent, %d subtree) %s\n",
 393                 it->entry_count, it->subtree_nr,
 394                 sha1_to_hex(it->sha1));
 395 #endif
 396         return i;
 397 }
 398
 399 int cache_tree_update(struct cache_tree *it,
 400                       const struct cache_entry * const *cache,
 401                       int entries,
 402                       int flags)
 403 {
 404         int i, skip;
 405         i = verify_cache(cache, entries, flags);
 406         if (i)
 407                 return i;
 408         i = update_one(it, cache, entries, "", 0, &skip, flags);
 409         if (i < 0)
 410                 return i;
 411         return 0;
 412 }
 413
 414 static void write_one(struct strbuf *buffer, struct cache_tree *it,
 415                       const char *path, int pathlen)
 416 {
 417         int i;
 418
 419         /* One "cache-tree" entry consists of the following:
 420          * path (NUL terminated)
 421          * entry_count, subtree_nr ("%d %d\n")
 422          * tree-sha1 (missing if invalid)
 423          * subtree_nr "cache-tree" entries for subtrees.
 424          */
 425         strbuf_grow(buffer, pathlen + 100);
 426         strbuf_add(buffer, path, pathlen);
 427         strbuf_addf(buffer, "%c%d %d\n", 0, it->entry_count, it->subtree_nr);
 428
 429 #if DEBUG
 430         if (0 <= it->entry_count)
 431                 fprintf(stderr, "cache-tree <%.*s> (%d ent, %d subtree) %s\n",
 432                         pathlen, path, it->entry_count, it->subtree_nr,
 433                         sha1_to_hex(it->sha1));
 434         else
 435                 fprintf(stderr, "cache-tree <%.*s> (%d subtree) invalid\n",
 436                         pathlen, path, it->subtree_nr);
 437 #endif
 438
 439         if (0 <= it->entry_count) {
 440                 strbuf_add(buffer, it->sha1, 20);
 441         }
 442         for (i = 0; i < it->subtree_nr; i++) {
 443                 struct cache_tree_sub *down = it->down[i];
 444                 if (i) {
 445                         struct cache_tree_sub *prev = it->down[i-1];
 446                         if (subtree_name_cmp(down->name, down->namelen,
 447                                              prev->name, prev->namelen) <= 0)
 448                                 die("fatal - unsorted cache subtree");
 449                 }
 450                 write_one(buffer, down->cache_tree, down->name, down->namelen);
 451         }
 452 }
 453
 454 void cache_tree_write(struct strbuf *sb, struct cache_tree *root)
 455 {
 456         write_one(sb, root, "", 0);
 457 }
 458
 459 static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
 460 {
 461         const char *buf = *buffer;
 462         unsigned long size = *size_p;
 463         const char *cp;
 464         char *ep;
 465         struct cache_tree *it;
 466         int i, subtree_nr;
 467
 468         it = NULL;
 469         /* skip name, but make sure name exists */
 470         while (size && *buf) {
 471                 size--;
 472                 buf++;
 473         }
 474         if (!size)
 475                 goto free_return;
 476         buf++; size--;
 477         it = cache_tree();
 478
 479         cp = buf;
 480         it->entry_count = strtol(cp, &ep, 10);
 481         if (cp == ep)
 482                 goto free_return;
 483         cp = ep;
 484         subtree_nr = strtol(cp, &ep, 10);
 485         if (cp == ep)
 486                 goto free_return;
 487         while (size && *buf && *buf != '\n') {
 488                 size--;
 489                 buf++;
 490         }
 491         if (!size)
 492                 goto free_return;
 493         buf++; size--;
 494         if (0 <= it->entry_count) {
 495                 if (size < 20)
 496                         goto free_return;
 497                 hashcpy(it->sha1, (const unsigned char*)buf);
 498                 buf += 20;
 499                 size -= 20;
 500         }
 501
 502 #if DEBUG
 503         if (0 <= it->entry_count)
 504                 fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
 505                         *buffer, it->entry_count, subtree_nr,
 506                         sha1_to_hex(it->sha1));
 507         else
 508                 fprintf(stderr, "cache-tree <%s> (%d subtrees) invalid\n",
 509                         *buffer, subtree_nr);
 510 #endif
 511
 512         /*
 513          * Just a heuristic -- we do not add directories that often but
 514          * we do not want to have to extend it immediately when we do,
 515          * hence +2.
 516          */
 517         it->subtree_alloc = subtree_nr + 2;
 518         it->down = xcalloc(it->subtree_alloc, sizeof(struct cache_tree_sub *));
 519         for (i = 0; i < subtree_nr; i++) {
 520                 /* read each subtree */
 521                 struct cache_tree *sub;
 522                 struct cache_tree_sub *subtree;
 523                 const char *name = buf;
 524
 525                 sub = read_one(&buf, &size);
 526                 if (!sub)
 527                         goto free_return;
 528                 subtree = cache_tree_sub(it, name);
 529                 subtree->cache_tree = sub;
 530         }
 531         if (subtree_nr != it->subtree_nr)
 532                 die("cache-tree: internal error");
 533         *buffer = buf;
 534         *size_p = size;
 535         return it;
 536
 537  free_return:
 538         cache_tree_free(&it);
 539         return NULL;
 540 }
 541
 542 struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
 543 {
 544         if (buffer[0])
 545                 return NULL; /* not the whole tree */
 546         return read_one(&buffer, &size);
 547 }
 548
 549 static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
 550 {
 551         if (!it)
 552                 return NULL;
 553         while (*path) {
 554                 const char *slash;
 555                 struct cache_tree_sub *sub;
 556
 557                 slash = strchrnul(path, '/');
 558                 /*
 559                  * Between path and slash is the name of the subtree
 560                  * to look for.
 561                  */
 562                 sub = find_subtree(it, path, slash - path, 0);
 563                 if (!sub)
 564                         return NULL;
 565                 it = sub->cache_tree;
 566
 567                 path = slash;
 568                 while (*path == '/')
 569                         path++;
 570         }
 571         return it;
 572 }
 573
 574 int write_cache_as_tree(unsigned char *sha1, int flags, const char *prefix)
 575 {
 576         int entries, was_valid, newfd;
 577         struct lock_file *lock_file;
 578
 579         /*
 580          * We can't free this memory, it becomes part of a linked list
 581          * parsed atexit()
 582          */
 583         lock_file = xcalloc(1, sizeof(struct lock_file));
 584
 585         newfd = hold_locked_index(lock_file, 1);
 586
 587         entries = read_cache();
 588         if (entries < 0)
 589                 return WRITE_TREE_UNREADABLE_INDEX;
 590         if (flags & WRITE_TREE_IGNORE_CACHE_TREE)
 591                 cache_tree_free(&(active_cache_tree));
 592
 593         if (!active_cache_tree)
 594                 active_cache_tree = cache_tree();
 595
 596         was_valid = cache_tree_fully_valid(active_cache_tree);
 597         if (!was_valid) {
 598                 if (cache_tree_update(active_cache_tree,
 599                                       (const struct cache_entry * const *)active_cache,
 600                                       active_nr, flags) < 0)
 601                         return WRITE_TREE_UNMERGED_INDEX;
 602                 if (0 <= newfd) {
 603                         if (!write_cache(newfd, active_cache, active_nr) &&
 604                             !commit_lock_file(lock_file))
 605                                 newfd = -1;
 606                 }
 607                 /* Not being able to write is fine -- we are only interested
 608                  * in updating the cache-tree part, and if the next caller
 609                  * ends up using the old index with unupdated cache-tree part
 610                  * it misses the work we did here, but that is just a
 611                  * performance penalty and not a big deal.
 612                  */
 613         }
 614
 615         if (prefix) {
 616                 struct cache_tree *subtree =
 617                         cache_tree_find(active_cache_tree, prefix);
 618                 if (!subtree)
 619                         return WRITE_TREE_PREFIX_ERROR;
 620                 hashcpy(sha1, subtree->sha1);
 621         }
 622         else
 623                 hashcpy(sha1, active_cache_tree->sha1);
 624
 625         if (0 <= newfd)
 626                 rollback_lock_file(lock_file);
 627
 628         return 0;
 629 }
 630
 631 static void prime_cache_tree_rec(struct cache_tree *it, struct tree *tree)
 632 {
 633         struct tree_desc desc;
 634         struct name_entry entry;
 635         int cnt;
 636
 637         hashcpy(it->sha1, tree->object.sha1);
 638         init_tree_desc(&desc, tree->buffer, tree->size);
 639         cnt = 0;
 640         while (tree_entry(&desc, &entry)) {
 641                 if (!S_ISDIR(entry.mode))
 642                         cnt++;
 643                 else {
 644                         struct cache_tree_sub *sub;
 645                         struct tree *subtree = lookup_tree(entry.sha1);
 646                         if (!subtree->object.parsed)
 647                                 parse_tree(subtree);
 648                         sub = cache_tree_sub(it, entry.path);
 649                         sub->cache_tree = cache_tree();
 650                         prime_cache_tree_rec(sub->cache_tree, subtree);
 651                         cnt += sub->cache_tree->entry_count;
 652                 }
 653         }
 654         it->entry_count = cnt;
 655 }
 656
 657 void prime_cache_tree(struct cache_tree **it, struct tree *tree)
 658 {
 659         cache_tree_free(it);
 660         *it = cache_tree();
 661         prime_cache_tree_rec(*it, tree);
 662 }
 663
 664 /*
 665  * find the cache_tree that corresponds to the current level without
 666  * exploding the full path into textual form.  The root of the
 667  * cache tree is given as "root", and our current level is "info".
 668  * (1) When at root level, info->prev is NULL, so it is "root" itself.
 669  * (2) Otherwise, find the cache_tree that corresponds to one level
 670  *     above us, and find ourselves in there.
 671  */
 672 static struct cache_tree *find_cache_tree_from_traversal(struct cache_tree *root,
 673                                                          struct traverse_info *info)
 674 {
 675         struct cache_tree *our_parent;
 676
 677         if (!info->prev)
 678                 return root;
 679         our_parent = find_cache_tree_from_traversal(root, info->prev);
 680         return cache_tree_find(our_parent, info->name.path);
 681 }
 682
 683 int cache_tree_matches_traversal(struct cache_tree *root,
 684                                  struct name_entry *ent,
 685                                  struct traverse_info *info)
 686 {
 687         struct cache_tree *it;
 688
 689         it = find_cache_tree_from_traversal(root, info);
 690         it = cache_tree_find(it, ent->path);
 691         if (it && it->entry_count > 0 && !hashcmp(ent->sha1, it->sha1))
 692                 return it->entry_count;
 693         return 0;
 694 }
 695
 696 int update_main_cache_tree(int flags)
 697 {
 698         if (!the_index.cache_tree)
 699                 the_index.cache_tree = cache_tree();
 700         return cache_tree_update(the_index.cache_tree,
 701                                  (const struct cache_entry * const *)the_index.cache,
 702                                  the_index.cache_nr, flags);
 703 }