cache-tree.c

   1 #include "cache.h"
   2 #include "tree.h"
   3 #include "cache-tree.h"
   4
   5 #define DEBUG 0
   6
   7 struct cache_tree *cache_tree(void)
   8 {
   9         struct cache_tree *it = xcalloc(1, sizeof(struct cache_tree));
  10         it->entry_count = -1;
  11         return it;
  12 }
  13
  14 void cache_tree_free(struct cache_tree *it)
  15 {
  16         int i;
  17
  18         if (!it)
  19                 return;
  20         for (i = 0; i < it->subtree_nr; i++)
  21                 cache_tree_free(it->down[i]->cache_tree);
  22         free(it->down);
  23         free(it);
  24 }
  25
  26 static struct cache_tree_sub *find_subtree(struct cache_tree *it,
  27                                            const char *path,
  28                                            int pathlen,
  29                                            int create)
  30 {
  31         int i;
  32         struct cache_tree_sub *down;
  33         for (i = 0; i < it->subtree_nr; i++) {
  34                 down = it->down[i];
  35                 if (down->namelen == pathlen &&
  36                     !memcmp(down->name, path, pathlen))
  37                         return down;
  38         }
  39         if (!create)
  40                 return NULL;
  41         if (it->subtree_alloc <= it->subtree_nr) {
  42                 it->subtree_alloc = alloc_nr(it->subtree_alloc);
  43                 it->down = xrealloc(it->down, it->subtree_alloc *
  44                                     sizeof(*it->down));
  45         }
  46         down = xmalloc(sizeof(*down) + pathlen + 1);
  47         down->cache_tree = NULL; /* cache_tree(); */
  48         down->namelen = pathlen;
  49         memcpy(down->name, path, pathlen);
  50         down->name[pathlen] = 0; /* not strictly needed */
  51         it->down[it->subtree_nr++] = down;
  52         return down;
  53 }
  54
  55 void cache_tree_invalidate_path(struct cache_tree *it, const char *path)
  56 {
  57         /* a/b/c
  58          * ==> invalidate self
  59          * ==> find "a", have it invalidate "b/c"
  60          * a
  61          * ==> invalidate self
  62          * ==> if "a" exists as a subtree, remove it.
  63          */
  64         const char *slash;
  65         int namelen;
  66         struct cache_tree_sub *down;
  67
  68         if (!it)
  69                 return;
  70         slash = strchr(path, '/');
  71         it->entry_count = -1;
  72         if (!slash) {
  73                 int i;
  74                 namelen = strlen(path);
  75                 for (i = 0; i < it->subtree_nr; i++) {
  76                         if (it->down[i]->namelen == namelen &&
  77                             !memcmp(it->down[i]->name, path, namelen))
  78                                 break;
  79                 }
  80                 if (i < it->subtree_nr) {
  81                         cache_tree_free(it->down[i]->cache_tree);
  82                         free(it->down[i]);
  83                         /* 0 1 2 3 4 5
  84                          *       ^     ^subtree_nr = 6
  85                          *       i
  86                          * move 4 and 5 up one place (2 entries)
  87                          * 2 = 6 - 3 - 1 = subtree_nr - i - 1
  88                          */
  89                         memmove(it->down+i, it->down+i+1,
  90                                 sizeof(struct cache_tree_sub *) *
  91                                 (it->subtree_nr - i - 1));
  92                         it->subtree_nr--;
  93                 }
  94                 return;
  95         }
  96         namelen = slash - path;
  97         down = find_subtree(it, path, namelen, 0);
  98         if (down)
  99                 cache_tree_invalidate_path(down->cache_tree, slash + 1);
 100 }
 101
 102 static int verify_cache(struct cache_entry **cache,
 103                         int entries)
 104 {
 105         int i, funny;
 106
 107         /* Verify that the tree is merged */
 108         funny = 0;
 109         for (i = 0; i < entries; i++) {
 110                 struct cache_entry *ce = cache[i];
 111                 if (ce_stage(ce)) {
 112                         if (10 < ++funny) {
 113                                 fprintf(stderr, "...\n");
 114                                 break;
 115                         }
 116                         fprintf(stderr, "%s: unmerged (%s)\n",
 117                                 ce->name, sha1_to_hex(ce->sha1));
 118                 }
 119         }
 120         if (funny)
 121                 return -1;
 122
 123         /* Also verify that the cache does not have path and path/file
 124          * at the same time.  At this point we know the cache has only
 125          * stage 0 entries.
 126          */
 127         funny = 0;
 128         for (i = 0; i < entries - 1; i++) {
 129                 /* path/file always comes after path because of the way
 130                  * the cache is sorted.  Also path can appear only once,
 131                  * which means conflicting one would immediately follow.
 132                  */
 133                 const char *this_name = cache[i]->name;
 134                 const char *next_name = cache[i+1]->name;
 135                 int this_len = strlen(this_name);
 136                 if (this_len < strlen(next_name) &&
 137                     strncmp(this_name, next_name, this_len) == 0 &&
 138                     next_name[this_len] == '/') {
 139                         if (10 < ++funny) {
 140                                 fprintf(stderr, "...\n");
 141                                 break;
 142                         }
 143                         fprintf(stderr, "You have both %s and %s\n",
 144                                 this_name, next_name);
 145                 }
 146         }
 147         if (funny)
 148                 return -1;
 149         return 0;
 150 }
 151
 152 static void discard_unused_subtrees(struct cache_tree *it)
 153 {
 154         struct cache_tree_sub **down = it->down;
 155         int nr = it->subtree_nr;
 156         int dst, src;
 157         for (dst = src = 0; src < nr; src++) {
 158                 struct cache_tree_sub *s = down[src];
 159                 if (s->used)
 160                         down[dst++] = s;
 161                 else {
 162                         cache_tree_free(s->cache_tree);
 163                         free(s);
 164                         it->subtree_nr--;
 165                 }
 166         }
 167 }
 168
 169 static int update_one(struct cache_tree *it,
 170                       struct cache_entry **cache,
 171                       int entries,
 172                       const char *base,
 173                       int baselen,
 174                       int missing_ok)
 175 {
 176         unsigned long size, offset;
 177         char *buffer;
 178         int i;
 179
 180         if (0 <= it->entry_count)
 181                 return it->entry_count;
 182
 183         /*
 184          * We first scan for subtrees and update them; we start by
 185          * marking existing subtrees -- the ones that are unmarked
 186          * should not be in the result.
 187          */
 188         for (i = 0; i < it->subtree_nr; i++)
 189                 it->down[i]->used = 0;
 190
 191         /*
 192          * Find the subtrees and update them.
 193          */
 194         for (i = 0; i < entries; i++) {
 195                 struct cache_entry *ce = cache[i];
 196                 struct cache_tree_sub *sub;
 197                 const char *path, *slash;
 198                 int pathlen, sublen, subcnt;
 199
 200                 path = ce->name;
 201                 pathlen = ce_namelen(ce);
 202                 if (pathlen <= baselen || memcmp(base, path, baselen))
 203                         break; /* at the end of this level */
 204
 205                 slash = strchr(path + baselen, '/');
 206                 if (!slash)
 207                         continue;
 208                 /*
 209                  * a/bbb/c (base = a/, slash = /c)
 210                  * ==>
 211                  * path+baselen = bbb/c, sublen = 3
 212                  */
 213                 sublen = slash - (path + baselen);
 214                 sub = find_subtree(it, path + baselen, sublen, 1);
 215                 if (!sub->cache_tree)
 216                         sub->cache_tree = cache_tree();
 217                 subcnt = update_one(sub->cache_tree,
 218                                     cache + i, entries - i,
 219                                     path,
 220                                     baselen + sublen + 1,
 221                                     missing_ok);
 222                 i += subcnt - 1;
 223                 sub->used = 1;
 224         }
 225
 226         discard_unused_subtrees(it);
 227
 228         /*
 229          * Then write out the tree object for this level.
 230          */
 231         size = 8192;
 232         buffer = xmalloc(size);
 233         offset = 0;
 234
 235         for (i = 0; i < entries; i++) {
 236                 struct cache_entry *ce = cache[i];
 237                 struct cache_tree_sub *sub;
 238                 const char *path, *slash;
 239                 int pathlen, entlen;
 240                 const unsigned char *sha1;
 241                 unsigned mode;
 242
 243                 path = ce->name;
 244                 pathlen = ce_namelen(ce);
 245                 if (pathlen <= baselen || memcmp(base, path, baselen))
 246                         break; /* at the end of this level */
 247
 248                 slash = strchr(path + baselen, '/');
 249                 if (slash) {
 250                         entlen = slash - (path + baselen);
 251                         sub = find_subtree(it, path + baselen, entlen, 0);
 252                         if (!sub)
 253                                 die("cache-tree.c: '%.*s' in '%s' not found",
 254                                     entlen, path + baselen, path);
 255                         i += sub->cache_tree->entry_count - 1;
 256                         sha1 = sub->cache_tree->sha1;
 257                         mode = S_IFDIR;
 258                 }
 259                 else {
 260                         sha1 = ce->sha1;
 261                         mode = ntohl(ce->ce_mode);
 262                         entlen = pathlen - baselen;
 263                 }
 264                 if (!missing_ok && !has_sha1_file(sha1))
 265                         return error("invalid object %s", sha1_to_hex(sha1));
 266
 267                 if (!ce->ce_mode)
 268                         continue; /* entry being removed */
 269
 270                 if (size < offset + entlen + 100) {
 271                         size = alloc_nr(offset + entlen + 100);
 272                         buffer = xrealloc(buffer, size);
 273                 }
 274                 offset += sprintf(buffer + offset,
 275                                   "%o %.*s", mode, entlen, path + baselen);
 276                 buffer[offset++] = 0;
 277                 memcpy(buffer + offset, sha1, 20);
 278                 offset += 20;
 279
 280 #if DEBUG
 281                 fprintf(stderr, "cache-tree %o %.*s\n",
 282                         mode, entlen, path + baselen);
 283 #endif
 284         }
 285
 286         write_sha1_file(buffer, offset, tree_type, it->sha1);
 287         free(buffer);
 288         it->entry_count = i;
 289 #if DEBUG
 290         fprintf(stderr, "cache-tree (%d ent, %d subtree) %s\n",
 291                 it->entry_count, it->subtree_nr,
 292                 sha1_to_hex(it->sha1));
 293 #endif
 294         return i;
 295 }
 296
 297 int cache_tree_update(struct cache_tree *it,
 298                       struct cache_entry **cache,
 299                       int entries,
 300                       int missing_ok)
 301 {
 302         int i;
 303         i = verify_cache(cache, entries);
 304         if (i)
 305                 return i;
 306         i = update_one(it, cache, entries, "", 0, missing_ok);
 307         if (i < 0)
 308                 return i;
 309         return 0;
 310 }
 311
 312 static void *write_one(struct cache_tree *it,
 313                        char *path,
 314                        int pathlen,
 315                        char *buffer,
 316                        unsigned long *size,
 317                        unsigned long *offset)
 318 {
 319         int i;
 320
 321         /* One "cache-tree" entry consists of the following:
 322          * path (NUL terminated)
 323          * entry_count, subtree_nr ("%d %d\n")
 324          * tree-sha1 (missing if invalid)
 325          * subtree_nr "cache-tree" entries for subtrees.
 326          */
 327         if (*size < *offset + pathlen + 100) {
 328                 *size = alloc_nr(*offset + pathlen + 100);
 329                 buffer = xrealloc(buffer, *size);
 330         }
 331         *offset += sprintf(buffer + *offset, "%.*s%c%d %d\n",
 332                            pathlen, path, 0,
 333                            it->entry_count, it->subtree_nr);
 334
 335 #if DEBUG
 336         if (0 <= it->entry_count)
 337                 fprintf(stderr, "cache-tree <%.*s> (%d ent, %d subtree) %s\n",
 338                         pathlen, path, it->entry_count, it->subtree_nr,
 339                         sha1_to_hex(it->sha1));
 340         else
 341                 fprintf(stderr, "cache-tree <%.*s> (%d subtree) invalid\n",
 342                         pathlen, path, it->subtree_nr);
 343 #endif
 344
 345         if (0 <= it->entry_count) {
 346                 memcpy(buffer + *offset, it->sha1, 20);
 347                 *offset += 20;
 348         }
 349         for (i = 0; i < it->subtree_nr; i++) {
 350                 struct cache_tree_sub *down = it->down[i];
 351                 buffer = write_one(down->cache_tree, down->name, down->namelen,
 352                                    buffer, size, offset);
 353         }
 354         return buffer;
 355 }
 356
 357 static void *cache_tree_write(const unsigned char *cache_sha1,
 358                               struct cache_tree *root,
 359                               unsigned long *offset_p)
 360 {
 361         char path[PATH_MAX];
 362         unsigned long size = 8192;
 363         char *buffer = xmalloc(size);
 364
 365         /* the cache checksum of the corresponding index file. */
 366         memcpy(buffer, cache_sha1, 20);
 367         *offset_p = 20;
 368         path[0] = 0;
 369         return write_one(root, path, 0, buffer, &size, offset_p);
 370 }
 371
 372 static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
 373 {
 374         const char *buf = *buffer;
 375         unsigned long size = *size_p;
 376         struct cache_tree *it;
 377         int i, subtree_nr;
 378
 379         it = NULL;
 380         /* skip name, but make sure name exists */
 381         while (size && *buf) {
 382                 size--;
 383                 buf++;
 384         }
 385         if (!size)
 386                 goto free_return;
 387         buf++; size--;
 388         it = cache_tree();
 389         if (sscanf(buf, "%d %d\n", &it->entry_count, &subtree_nr) != 2)
 390                 goto free_return;
 391         while (size && *buf && *buf != '\n') {
 392                 size--;
 393                 buf++;
 394         }
 395         if (!size)
 396                 goto free_return;
 397         buf++; size--;
 398         if (0 <= it->entry_count) {
 399                 if (size < 20)
 400                         goto free_return;
 401                 memcpy(it->sha1, buf, 20);
 402                 buf += 20;
 403                 size -= 20;
 404         }
 405
 406 #if DEBUG
 407         if (0 <= it->entry_count)
 408                 fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
 409                         *buffer, it->entry_count, subtree_nr,
 410                         sha1_to_hex(it->sha1));
 411         else
 412                 fprintf(stderr, "cache-tree <%s> (%d subtrees) invalid\n",
 413                         *buffer, subtree_nr);
 414 #endif
 415
 416         /*
 417          * Just a heuristic -- we do not add directories that often but
 418          * we do not want to have to extend it immediately when we do,
 419          * hence +2.
 420          */
 421         it->subtree_alloc = subtree_nr + 2;
 422         it->down = xcalloc(it->subtree_alloc, sizeof(struct cache_tree_sub *));
 423         for (i = 0; i < subtree_nr; i++) {
 424                 /* read each subtree */
 425                 struct cache_tree *sub;
 426                 const char *name = buf;
 427                 int namelen;
 428                 sub = read_one(&buf, &size);
 429                 if (!sub)
 430                         goto free_return;
 431                 namelen = strlen(name);
 432                 it->down[i] = find_subtree(it, name, namelen, 1);
 433                 it->down[i]->cache_tree = sub;
 434         }
 435         if (subtree_nr != it->subtree_nr)
 436                 die("cache-tree: internal error");
 437         *buffer = buf;
 438         *size_p = size;
 439         return it;
 440
 441  free_return:
 442         cache_tree_free(it);
 443         return NULL;
 444 }
 445
 446 static struct cache_tree *cache_tree_read(unsigned char *sha1,
 447                                           const char *buffer,
 448                                           unsigned long size)
 449 {
 450         /* check the cache-tree matches the index */
 451         if (memcmp(buffer, sha1, 20))
 452                 return NULL; /* checksum mismatch */
 453         if (buffer[20])
 454                 return NULL; /* not the whole tree */
 455         buffer += 20;
 456         size -= 20;
 457         return read_one(&buffer, &size);
 458 }
 459
 460 struct cache_tree *read_cache_tree(unsigned char *sha1)
 461 {
 462         int fd;
 463         struct stat st;
 464         char path[PATH_MAX];
 465         unsigned long size = 0;
 466         void *map;
 467         struct cache_tree *it;
 468
 469         sprintf(path, "%s.aux", get_index_file());
 470         fd = open(path, O_RDONLY);
 471         if (fd < 0)
 472                 return cache_tree();
 473
 474         if (fstat(fd, &st))
 475                 return cache_tree();
 476         size = st.st_size;
 477         map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
 478         close(fd);
 479         if (map == MAP_FAILED)
 480                 return cache_tree();
 481         it = cache_tree_read(sha1, map, size);
 482         munmap(map, size);
 483         if (!it)
 484                 return cache_tree();
 485         return it;
 486 }
 487
 488 int write_cache_tree(const unsigned char *sha1, struct cache_tree *root)
 489 {
 490         char path[PATH_MAX];
 491         unsigned long size = 0;
 492         void *buf, *buffer;
 493         int fd, ret = -1;
 494
 495         sprintf(path, "%s.aux", get_index_file());
 496         if (!root) {
 497                 unlink(path);
 498                 return -1;
 499         }
 500         fd = open(path, O_WRONLY|O_CREAT, 0666);
 501         if (fd < 0)
 502                 return -1;
 503         buffer = buf = cache_tree_write(sha1, root, &size);
 504         while (size) {
 505                 int written = xwrite(fd, buf, size);
 506                 if (written <= 0)
 507                         goto fail;
 508                 buf += written;
 509                 size -= written;
 510         }
 511         ret = 0;
 512
 513  fail:
 514         close(fd);
 515         free(buffer);
 516         if (ret)
 517                 unlink(path);
 518         return ret;
 519 }