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