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)) {
 159                         if (10 < ++funny) {
 160                                 fprintf(stderr, "...\n");
 161                                 break;
 162                         }
 163                         fprintf(stderr, "%s: unmerged (%s)\n",
 164                                 ce->name, sha1_to_hex(ce->sha1));
 165                 }
 166         }
 167         if (funny)
 168                 return -1;
 169
 170         /* Also verify that the cache does not have path and path/file
 171          * at the same time.  At this point we know the cache has only
 172          * stage 0 entries.
 173          */
 174         funny = 0;
 175         for (i = 0; i < entries - 1; i++) {
 176                 /* path/file always comes after path because of the way
 177                  * the cache is sorted.  Also path can appear only once,
 178                  * which means conflicting one would immediately follow.
 179                  */
 180                 const char *this_name = cache[i]->name;
 181                 const char *next_name = cache[i+1]->name;
 182                 int this_len = strlen(this_name);
 183                 if (this_len < strlen(next_name) &&
 184                     strncmp(this_name, next_name, this_len) == 0 &&
 185                     next_name[this_len] == '/') {
 186                         if (10 < ++funny) {
 187                                 fprintf(stderr, "...\n");
 188                                 break;
 189                         }
 190                         fprintf(stderr, "You have both %s and %s\n",
 191                                 this_name, next_name);
 192                 }
 193         }
 194         if (funny)
 195                 return -1;
 196         return 0;
 197 }
 198
 199 static void discard_unused_subtrees(struct cache_tree *it)
 200 {
 201         struct cache_tree_sub **down = it->down;
 202         int nr = it->subtree_nr;
 203         int dst, src;
 204         for (dst = src = 0; src < nr; src++) {
 205                 struct cache_tree_sub *s = down[src];
 206                 if (s->used)
 207                         down[dst++] = s;
 208                 else {
 209                         cache_tree_free(&s->cache_tree);
 210                         free(s);
 211                         it->subtree_nr--;
 212                 }
 213         }
 214 }
 215
 216 int cache_tree_fully_valid(struct cache_tree *it)
 217 {
 218         int i;
 219         if (!it)
 220                 return 0;
 221         if (it->entry_count < 0 || !has_sha1_file(it->sha1))
 222                 return 0;
 223         for (i = 0; i < it->subtree_nr; i++) {
 224                 if (!cache_tree_fully_valid(it->down[i]->cache_tree))
 225                         return 0;
 226         }
 227         return 1;
 228 }
 229
 230 static int update_one(struct cache_tree *it,
 231                       struct cache_entry **cache,
 232                       int entries,
 233                       const char *base,
 234                       int baselen,
 235                       int missing_ok,
 236                       int dryrun)
 237 {
 238         struct strbuf buffer;
 239         int i;
 240
 241         if (0 <= it->entry_count && has_sha1_file(it->sha1))
 242                 return it->entry_count;
 243
 244         /*
 245          * We first scan for subtrees and update them; we start by
 246          * marking existing subtrees -- the ones that are unmarked
 247          * should not be in the result.
 248          */
 249         for (i = 0; i < it->subtree_nr; i++)
 250                 it->down[i]->used = 0;
 251
 252         /*
 253          * Find the subtrees and update them.
 254          */
 255         for (i = 0; i < entries; i++) {
 256                 struct cache_entry *ce = cache[i];
 257                 struct cache_tree_sub *sub;
 258                 const char *path, *slash;
 259                 int pathlen, sublen, subcnt;
 260
 261                 path = ce->name;
 262                 pathlen = ce_namelen(ce);
 263                 if (pathlen <= baselen || memcmp(base, path, baselen))
 264                         break; /* at the end of this level */
 265
 266                 slash = strchr(path + baselen, '/');
 267                 if (!slash)
 268                         continue;
 269                 /*
 270                  * a/bbb/c (base = a/, slash = /c)
 271                  * ==>
 272                  * path+baselen = bbb/c, sublen = 3
 273                  */
 274                 sublen = slash - (path + baselen);
 275                 sub = find_subtree(it, path + baselen, sublen, 1);
 276                 if (!sub->cache_tree)
 277                         sub->cache_tree = cache_tree();
 278                 subcnt = update_one(sub->cache_tree,
 279                                     cache + i, entries - i,
 280                                     path,
 281                                     baselen + sublen + 1,
 282                                     missing_ok,
 283                                     dryrun);
 284                 if (subcnt < 0)
 285                         return subcnt;
 286                 i += subcnt - 1;
 287                 sub->used = 1;
 288         }
 289
 290         discard_unused_subtrees(it);
 291
 292         /*
 293          * Then write out the tree object for this level.
 294          */
 295         strbuf_init(&buffer, 8192);
 296
 297         for (i = 0; i < entries; i++) {
 298                 struct cache_entry *ce = cache[i];
 299                 struct cache_tree_sub *sub;
 300                 const char *path, *slash;
 301                 int pathlen, entlen;
 302                 const unsigned char *sha1;
 303                 unsigned mode;
 304
 305                 path = ce->name;
 306                 pathlen = ce_namelen(ce);
 307                 if (pathlen <= baselen || memcmp(base, path, baselen))
 308                         break; /* at the end of this level */
 309
 310                 slash = strchr(path + baselen, '/');
 311                 if (slash) {
 312                         entlen = slash - (path + baselen);
 313                         sub = find_subtree(it, path + baselen, entlen, 0);
 314                         if (!sub)
 315                                 die("cache-tree.c: '%.*s' in '%s' not found",
 316                                     entlen, path + baselen, path);
 317                         i += sub->cache_tree->entry_count - 1;
 318                         sha1 = sub->cache_tree->sha1;
 319                         mode = S_IFDIR;
 320                 }
 321                 else {
 322                         sha1 = ce->sha1;
 323                         mode = ce->ce_mode;
 324                         entlen = pathlen - baselen;
 325                 }
 326                 if (mode != S_IFGITLINK && !missing_ok && !has_sha1_file(sha1))
 327                         return error("invalid object %s", sha1_to_hex(sha1));
 328
 329                 if (ce->ce_flags & CE_REMOVE)
 330                         continue; /* entry being removed */
 331
 332                 strbuf_grow(&buffer, entlen + 100);
 333                 strbuf_addf(&buffer, "%o %.*s%c", mode, entlen, path + baselen, '\0');
 334                 strbuf_add(&buffer, sha1, 20);
 335
 336 #if DEBUG
 337                 fprintf(stderr, "cache-tree update-one %o %.*s\n",
 338                         mode, entlen, path + baselen);
 339 #endif
 340         }
 341
 342         if (dryrun)
 343                 hash_sha1_file(buffer.buf, buffer.len, tree_type, it->sha1);
 344         else if (write_sha1_file(buffer.buf, buffer.len, tree_type, it->sha1)) {
 345                 strbuf_release(&buffer);
 346                 return -1;
 347         }
 348
 349         strbuf_release(&buffer);
 350         it->entry_count = i;
 351 #if DEBUG
 352         fprintf(stderr, "cache-tree update-one (%d ent, %d subtree) %s\n",
 353                 it->entry_count, it->subtree_nr,
 354                 sha1_to_hex(it->sha1));
 355 #endif
 356         return i;
 357 }
 358
 359 int cache_tree_update(struct cache_tree *it,
 360                       struct cache_entry **cache,
 361                       int entries,
 362                       int missing_ok,
 363                       int dryrun)
 364 {
 365         int i;
 366         i = verify_cache(cache, entries);
 367         if (i)
 368                 return i;
 369         i = update_one(it, cache, entries, "", 0, missing_ok, dryrun);
 370         if (i < 0)
 371                 return i;
 372         return 0;
 373 }
 374
 375 static void write_one(struct strbuf *buffer, struct cache_tree *it,
 376                       const char *path, int pathlen)
 377 {
 378         int i;
 379
 380         /* One "cache-tree" entry consists of the following:
 381          * path (NUL terminated)
 382          * entry_count, subtree_nr ("%d %d\n")
 383          * tree-sha1 (missing if invalid)
 384          * subtree_nr "cache-tree" entries for subtrees.
 385          */
 386         strbuf_grow(buffer, pathlen + 100);
 387         strbuf_add(buffer, path, pathlen);
 388         strbuf_addf(buffer, "%c%d %d\n", 0, it->entry_count, it->subtree_nr);
 389
 390 #if DEBUG
 391         if (0 <= it->entry_count)
 392                 fprintf(stderr, "cache-tree <%.*s> (%d ent, %d subtree) %s\n",
 393                         pathlen, path, it->entry_count, it->subtree_nr,
 394                         sha1_to_hex(it->sha1));
 395         else
 396                 fprintf(stderr, "cache-tree <%.*s> (%d subtree) invalid\n",
 397                         pathlen, path, it->subtree_nr);
 398 #endif
 399
 400         if (0 <= it->entry_count) {
 401                 strbuf_add(buffer, it->sha1, 20);
 402         }
 403         for (i = 0; i < it->subtree_nr; i++) {
 404                 struct cache_tree_sub *down = it->down[i];
 405                 if (i) {
 406                         struct cache_tree_sub *prev = it->down[i-1];
 407                         if (subtree_name_cmp(down->name, down->namelen,
 408                                              prev->name, prev->namelen) <= 0)
 409                                 die("fatal - unsorted cache subtree");
 410                 }
 411                 write_one(buffer, down->cache_tree, down->name, down->namelen);
 412         }
 413 }
 414
 415 void cache_tree_write(struct strbuf *sb, struct cache_tree *root)
 416 {
 417         write_one(sb, root, "", 0);
 418 }
 419
 420 static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
 421 {
 422         const char *buf = *buffer;
 423         unsigned long size = *size_p;
 424         const char *cp;
 425         char *ep;
 426         struct cache_tree *it;
 427         int i, subtree_nr;
 428
 429         it = NULL;
 430         /* skip name, but make sure name exists */
 431         while (size && *buf) {
 432                 size--;
 433                 buf++;
 434         }
 435         if (!size)
 436                 goto free_return;
 437         buf++; size--;
 438         it = cache_tree();
 439
 440         cp = buf;
 441         it->entry_count = strtol(cp, &ep, 10);
 442         if (cp == ep)
 443                 goto free_return;
 444         cp = ep;
 445         subtree_nr = strtol(cp, &ep, 10);
 446         if (cp == ep)
 447                 goto free_return;
 448         while (size && *buf && *buf != '\n') {
 449                 size--;
 450                 buf++;
 451         }
 452         if (!size)
 453                 goto free_return;
 454         buf++; size--;
 455         if (0 <= it->entry_count) {
 456                 if (size < 20)
 457                         goto free_return;
 458                 hashcpy(it->sha1, (const unsigned char*)buf);
 459                 buf += 20;
 460                 size -= 20;
 461         }
 462
 463 #if DEBUG
 464         if (0 <= it->entry_count)
 465                 fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
 466                         *buffer, it->entry_count, subtree_nr,
 467                         sha1_to_hex(it->sha1));
 468         else
 469                 fprintf(stderr, "cache-tree <%s> (%d subtrees) invalid\n",
 470                         *buffer, subtree_nr);
 471 #endif
 472
 473         /*
 474          * Just a heuristic -- we do not add directories that often but
 475          * we do not want to have to extend it immediately when we do,
 476          * hence +2.
 477          */
 478         it->subtree_alloc = subtree_nr + 2;
 479         it->down = xcalloc(it->subtree_alloc, sizeof(struct cache_tree_sub *));
 480         for (i = 0; i < subtree_nr; i++) {
 481                 /* read each subtree */
 482                 struct cache_tree *sub;
 483                 struct cache_tree_sub *subtree;
 484                 const char *name = buf;
 485
 486                 sub = read_one(&buf, &size);
 487                 if (!sub)
 488                         goto free_return;
 489                 subtree = cache_tree_sub(it, name);
 490                 subtree->cache_tree = sub;
 491         }
 492         if (subtree_nr != it->subtree_nr)
 493                 die("cache-tree: internal error");
 494         *buffer = buf;
 495         *size_p = size;
 496         return it;
 497
 498  free_return:
 499         cache_tree_free(&it);
 500         return NULL;
 501 }
 502
 503 struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
 504 {
 505         if (buffer[0])
 506                 return NULL; /* not the whole tree */
 507         return read_one(&buffer, &size);
 508 }
 509
 510 struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
 511 {
 512         while (*path) {
 513                 const char *slash;
 514                 struct cache_tree_sub *sub;
 515
 516                 slash = strchr(path, '/');
 517                 if (!slash)
 518                         slash = path + strlen(path);
 519                 /* between path and slash is the name of the
 520                  * subtree to look for.
 521                  */
 522                 sub = find_subtree(it, path, slash - path, 0);
 523                 if (!sub)
 524                         return NULL;
 525                 it = sub->cache_tree;
 526                 if (slash)
 527                         while (*slash && *slash == '/')
 528                                 slash++;
 529                 if (!slash || !*slash)
 530                         return it; /* prefix ended with slashes */
 531                 path = slash;
 532         }
 533         return it;
 534 }
 535
 536 int write_cache_as_tree(unsigned char *sha1, int missing_ok, const char *prefix)
 537 {
 538         int entries, was_valid, newfd;
 539
 540         /*
 541          * We can't free this memory, it becomes part of a linked list
 542          * parsed atexit()
 543          */
 544         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
 545
 546         newfd = hold_locked_index(lock_file, 1);
 547
 548         entries = read_cache();
 549         if (entries < 0)
 550                 return WRITE_TREE_UNREADABLE_INDEX;
 551
 552         if (!active_cache_tree)
 553                 active_cache_tree = cache_tree();
 554
 555         was_valid = cache_tree_fully_valid(active_cache_tree);
 556
 557         if (!was_valid) {
 558                 if (cache_tree_update(active_cache_tree,
 559                                       active_cache, active_nr,
 560                                       missing_ok, 0) < 0)
 561                         return WRITE_TREE_UNMERGED_INDEX;
 562                 if (0 <= newfd) {
 563                         if (!write_cache(newfd, active_cache, active_nr) &&
 564                             !commit_lock_file(lock_file))
 565                                 newfd = -1;
 566                 }
 567                 /* Not being able to write is fine -- we are only interested
 568                  * in updating the cache-tree part, and if the next caller
 569                  * ends up using the old index with unupdated cache-tree part
 570                  * it misses the work we did here, but that is just a
 571                  * performance penalty and not a big deal.
 572                  */
 573         }
 574
 575         if (prefix) {
 576                 struct cache_tree *subtree =
 577                         cache_tree_find(active_cache_tree, prefix);
 578                 if (!subtree)
 579                         return WRITE_TREE_PREFIX_ERROR;
 580                 hashcpy(sha1, subtree->sha1);
 581         }
 582         else
 583                 hashcpy(sha1, active_cache_tree->sha1);
 584
 585         if (0 <= newfd)
 586                 rollback_lock_file(lock_file);
 587
 588         return 0;
 589 }