cache-tree.c

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