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_p)
  15 {
  16         int i;
  17         struct cache_tree *it = *it_p;
  18
  19         if (!it)
  20                 return;
  21         for (i = 0; i < it->subtree_nr; i++)
  22                 if (it->down[i])
  23                         cache_tree_free(&it->down[i]->cache_tree);
  24         free(it->down);
  25         free(it);
  26         *it_p = NULL;
  27 }
  28
  29 static int subtree_name_cmp(const char *one, int onelen,
  30                             const char *two, int twolen)
  31 {
  32         if (onelen < twolen)
  33                 return -1;
  34         if (twolen < onelen)
  35                 return 1;
  36         return memcmp(one, two, onelen);
  37 }
  38
  39 static int subtree_pos(struct cache_tree *it, const char *path, int pathlen)
  40 {
  41         struct cache_tree_sub **down = it->down;
  42         int lo, hi;
  43         lo = 0;
  44         hi = it->subtree_nr;
  45         while (lo < hi) {
  46                 int mi = (lo + hi) / 2;
  47                 struct cache_tree_sub *mdl = down[mi];
  48                 int cmp = subtree_name_cmp(path, pathlen,
  49                                            mdl->name, mdl->namelen);
  50                 if (!cmp)
  51                         return mi;
  52                 if (cmp < 0)
  53                         hi = mi;
  54                 else
  55                         lo = mi + 1;
  56         }
  57         return -lo-1;
  58 }
  59
  60 static struct cache_tree_sub *find_subtree(struct cache_tree *it,
  61                                            const char *path,
  62                                            int pathlen,
  63                                            int create)
  64 {
  65         struct cache_tree_sub *down;
  66         int pos = subtree_pos(it, path, pathlen);
  67         if (0 <= pos)
  68                 return it->down[pos];
  69         if (!create)
  70                 return NULL;
  71
  72         pos = -pos-1;
  73         if (it->subtree_alloc <= it->subtree_nr) {
  74                 it->subtree_alloc = alloc_nr(it->subtree_alloc);
  75                 it->down = xrealloc(it->down, it->subtree_alloc *
  76                                     sizeof(*it->down));
  77         }
  78         it->subtree_nr++;
  79
  80         down = xmalloc(sizeof(*down) + pathlen + 1);
  81         down->cache_tree = NULL;
  82         down->namelen = pathlen;
  83         memcpy(down->name, path, pathlen);
  84         down->name[pathlen] = 0;
  85
  86         if (pos < it->subtree_nr)
  87                 memmove(it->down + pos + 1,
  88                         it->down + pos,
  89                         sizeof(down) * (it->subtree_nr - pos - 1));
  90         it->down[pos] = down;
  91         return down;
  92 }
  93
  94 struct cache_tree_sub *cache_tree_sub(struct cache_tree *it, const char *path)
  95 {
  96         int pathlen = strlen(path);
  97         return find_subtree(it, path, pathlen, 1);
  98 }
  99
 100 void cache_tree_invalidate_path(struct cache_tree *it, const char *path)
 101 {
 102         /* a/b/c
 103          * ==> invalidate self
 104          * ==> find "a", have it invalidate "b/c"
 105          * a
 106          * ==> invalidate self
 107          * ==> if "a" exists as a subtree, remove it.
 108          */
 109         const char *slash;
 110         int namelen;
 111         struct cache_tree_sub *down;
 112
 113 #if DEBUG
 114         fprintf(stderr, "cache-tree invalidate <%s>\n", path);
 115 #endif
 116
 117         if (!it)
 118                 return;
 119         slash = strchr(path, '/');
 120         it->entry_count = -1;
 121         if (!slash) {
 122                 int pos;
 123                 namelen = strlen(path);
 124                 pos = subtree_pos(it, path, namelen);
 125                 if (0 <= pos) {
 126                         cache_tree_free(&it->down[pos]->cache_tree);
 127                         free(it->down[pos]);
 128                         /* 0 1 2 3 4 5
 129                          *       ^     ^subtree_nr = 6
 130                          *       pos
 131                          * move 4 and 5 up one place (2 entries)
 132                          * 2 = 6 - 3 - 1 = subtree_nr - pos - 1
 133                          */
 134                         memmove(it->down+pos, it->down+pos+1,
 135                                 sizeof(struct cache_tree_sub *) *
 136                                 (it->subtree_nr - pos - 1));
 137                         it->subtree_nr--;
 138                 }
 139                 return;
 140         }
 141         namelen = slash - path;
 142         down = find_subtree(it, path, namelen, 0);
 143         if (down)
 144                 cache_tree_invalidate_path(down->cache_tree, slash + 1);
 145 }
 146
 147 static int verify_cache(struct cache_entry **cache,
 148                         int entries)
 149 {
 150         int i, funny;
 151
 152         /* Verify that the tree is merged */
 153         funny = 0;
 154         for (i = 0; i < entries; i++) {
 155                 struct cache_entry *ce = cache[i];
 156                 if (ce_stage(ce)) {
 157                         if (10 < ++funny) {
 158                                 fprintf(stderr, "...\n");
 159                                 break;
 160                         }
 161                         fprintf(stderr, "%s: unmerged (%s)\n",
 162                                 ce->name, sha1_to_hex(ce->sha1));
 163                 }
 164         }
 165         if (funny)
 166                 return -1;
 167
 168         /* Also verify that the cache does not have path and path/file
 169          * at the same time.  At this point we know the cache has only
 170          * stage 0 entries.
 171          */
 172         funny = 0;
 173         for (i = 0; i < entries - 1; i++) {
 174                 /* path/file always comes after path because of the way
 175                  * the cache is sorted.  Also path can appear only once,
 176                  * which means conflicting one would immediately follow.
 177                  */
 178                 const char *this_name = cache[i]->name;
 179                 const char *next_name = cache[i+1]->name;
 180                 int this_len = strlen(this_name);
 181                 if (this_len < strlen(next_name) &&
 182                     strncmp(this_name, next_name, this_len) == 0 &&
 183                     next_name[this_len] == '/') {
 184                         if (10 < ++funny) {
 185                                 fprintf(stderr, "...\n");
 186                                 break;
 187                         }
 188                         fprintf(stderr, "You have both %s and %s\n",
 189                                 this_name, next_name);
 190                 }
 191         }
 192         if (funny)
 193                 return -1;
 194         return 0;
 195 }
 196
 197 static void discard_unused_subtrees(struct cache_tree *it)
 198 {
 199         struct cache_tree_sub **down = it->down;
 200         int nr = it->subtree_nr;
 201         int dst, src;
 202         for (dst = src = 0; src < nr; src++) {
 203                 struct cache_tree_sub *s = down[src];
 204                 if (s->used)
 205                         down[dst++] = s;
 206                 else {
 207                         cache_tree_free(&s->cache_tree);
 208                         free(s);
 209                         it->subtree_nr--;
 210                 }
 211         }
 212 }
 213
 214 int cache_tree_fully_valid(struct cache_tree *it)
 215 {
 216         int i;
 217         if (!it)
 218                 return 0;
 219         if (it->entry_count < 0 || !has_sha1_file(it->sha1))
 220                 return 0;
 221         for (i = 0; i < it->subtree_nr; i++) {
 222                 if (!cache_tree_fully_valid(it->down[i]->cache_tree))
 223                         return 0;
 224         }
 225         return 1;
 226 }
 227
 228 static int update_one(struct cache_tree *it,
 229                       struct cache_entry **cache,
 230                       int entries,
 231                       const char *base,
 232                       int baselen,
 233                       int missing_ok,
 234                       int dryrun)
 235 {
 236         unsigned long size, offset;
 237         char *buffer;
 238         int i;
 239
 240         if (0 <= it->entry_count && has_sha1_file(it->sha1))
 241                 return it->entry_count;
 242
 243         /*
 244          * We first scan for subtrees and update them; we start by
 245          * marking existing subtrees -- the ones that are unmarked
 246          * should not be in the result.
 247          */
 248         for (i = 0; i < it->subtree_nr; i++)
 249                 it->down[i]->used = 0;
 250
 251         /*
 252          * Find the subtrees and update them.
 253          */
 254         for (i = 0; i < entries; i++) {
 255                 struct cache_entry *ce = cache[i];
 256                 struct cache_tree_sub *sub;
 257                 const char *path, *slash;
 258                 int pathlen, sublen, subcnt;
 259
 260                 path = ce->name;
 261                 pathlen = ce_namelen(ce);
 262                 if (pathlen <= baselen || memcmp(base, path, baselen))
 263                         break; /* at the end of this level */
 264
 265                 slash = strchr(path + baselen, '/');
 266                 if (!slash)
 267                         continue;
 268                 /*
 269                  * a/bbb/c (base = a/, slash = /c)
 270                  * ==>
 271                  * path+baselen = bbb/c, sublen = 3
 272                  */
 273                 sublen = slash - (path + baselen);
 274                 sub = find_subtree(it, path + baselen, sublen, 1);
 275                 if (!sub->cache_tree)
 276                         sub->cache_tree = cache_tree();
 277                 subcnt = update_one(sub->cache_tree,
 278                                     cache + i, entries - i,
 279                                     path,
 280                                     baselen + sublen + 1,
 281                                     missing_ok,
 282                                     dryrun);
 283                 i += subcnt - 1;
 284                 sub->used = 1;
 285         }
 286
 287         discard_unused_subtrees(it);
 288
 289         /*
 290          * Then write out the tree object for this level.
 291          */
 292         size = 8192;
 293         buffer = xmalloc(size);
 294         offset = 0;
 295
 296         for (i = 0; i < entries; i++) {
 297                 struct cache_entry *ce = cache[i];
 298                 struct cache_tree_sub *sub;
 299                 const char *path, *slash;
 300                 int pathlen, entlen;
 301                 const unsigned char *sha1;
 302                 unsigned mode;
 303
 304                 path = ce->name;
 305                 pathlen = ce_namelen(ce);
 306                 if (pathlen <= baselen || memcmp(base, path, baselen))
 307                         break; /* at the end of this level */
 308
 309                 slash = strchr(path + baselen, '/');
 310                 if (slash) {
 311                         entlen = slash - (path + baselen);
 312                         sub = find_subtree(it, path + baselen, entlen, 0);
 313                         if (!sub)
 314                                 die("cache-tree.c: '%.*s' in '%s' not found",
 315                                     entlen, path + baselen, path);
 316                         i += sub->cache_tree->entry_count - 1;
 317                         sha1 = sub->cache_tree->sha1;
 318                         mode = S_IFDIR;
 319                 }
 320                 else {
 321                         sha1 = ce->sha1;
 322                         mode = ntohl(ce->ce_mode);
 323                         entlen = pathlen - baselen;
 324                 }
 325                 if (!missing_ok && !has_sha1_file(sha1))
 326                         return error("invalid object %s", sha1_to_hex(sha1));
 327
 328                 if (!ce->ce_mode)
 329                         continue; /* entry being removed */
 330
 331                 if (size < offset + entlen + 100) {
 332                         size = alloc_nr(offset + entlen + 100);
 333                         buffer = xrealloc(buffer, size);
 334                 }
 335                 offset += sprintf(buffer + offset,
 336                                   "%o %.*s", mode, entlen, path + baselen);
 337                 buffer[offset++] = 0;
 338                 memcpy(buffer + offset, sha1, 20);
 339                 offset += 20;
 340
 341 #if DEBUG
 342                 fprintf(stderr, "cache-tree update-one %o %.*s\n",
 343                         mode, entlen, path + baselen);
 344 #endif
 345         }
 346
 347         if (dryrun) {
 348                 unsigned char hdr[200];
 349                 int hdrlen;
 350                 write_sha1_file_prepare(buffer, offset, tree_type, it->sha1,
 351                                         hdr, &hdrlen);
 352         }
 353         else
 354                 write_sha1_file(buffer, offset, tree_type, it->sha1);
 355         free(buffer);
 356         it->entry_count = i;
 357 #if DEBUG
 358         fprintf(stderr, "cache-tree update-one (%d ent, %d subtree) %s\n",
 359                 it->entry_count, it->subtree_nr,
 360                 sha1_to_hex(it->sha1));
 361 #endif
 362         return i;
 363 }
 364
 365 int cache_tree_update(struct cache_tree *it,
 366                       struct cache_entry **cache,
 367                       int entries,
 368                       int missing_ok,
 369                       int dryrun)
 370 {
 371         int i;
 372         i = verify_cache(cache, entries);
 373         if (i)
 374                 return i;
 375         i = update_one(it, cache, entries, "", 0, missing_ok, dryrun);
 376         if (i < 0)
 377                 return i;
 378         return 0;
 379 }
 380
 381 static void *write_one(struct cache_tree *it,
 382                        char *path,
 383                        int pathlen,
 384                        char *buffer,
 385                        unsigned long *size,
 386                        unsigned long *offset)
 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         if (*size < *offset + pathlen + 100) {
 397                 *size = alloc_nr(*offset + pathlen + 100);
 398                 buffer = xrealloc(buffer, *size);
 399         }
 400         *offset += sprintf(buffer + *offset, "%.*s%c%d %d\n",
 401                            pathlen, path, 0,
 402                            it->entry_count, it->subtree_nr);
 403
 404 #if DEBUG
 405         if (0 <= it->entry_count)
 406                 fprintf(stderr, "cache-tree <%.*s> (%d ent, %d subtree) %s\n",
 407                         pathlen, path, it->entry_count, it->subtree_nr,
 408                         sha1_to_hex(it->sha1));
 409         else
 410                 fprintf(stderr, "cache-tree <%.*s> (%d subtree) invalid\n",
 411                         pathlen, path, it->subtree_nr);
 412 #endif
 413
 414         if (0 <= it->entry_count) {
 415                 memcpy(buffer + *offset, it->sha1, 20);
 416                 *offset += 20;
 417         }
 418         for (i = 0; i < it->subtree_nr; i++) {
 419                 struct cache_tree_sub *down = it->down[i];
 420                 if (i) {
 421                         struct cache_tree_sub *prev = it->down[i-1];
 422                         if (subtree_name_cmp(down->name, down->namelen,
 423                                              prev->name, prev->namelen) <= 0)
 424                                 die("fatal - unsorted cache subtree");
 425                 }
 426                 buffer = write_one(down->cache_tree, down->name, down->namelen,
 427                                    buffer, size, offset);
 428         }
 429         return buffer;
 430 }
 431
 432 void *cache_tree_write(struct cache_tree *root, unsigned long *size_p)
 433 {
 434         char path[PATH_MAX];
 435         unsigned long size = 8192;
 436         char *buffer = xmalloc(size);
 437
 438         *size_p = 0;
 439         path[0] = 0;
 440         return write_one(root, path, 0, buffer, &size, size_p);
 441 }
 442
 443 static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
 444 {
 445         const char *buf = *buffer;
 446         unsigned long size = *size_p;
 447         const char *cp;
 448         char *ep;
 449         struct cache_tree *it;
 450         int i, subtree_nr;
 451
 452         it = NULL;
 453         /* skip name, but make sure name exists */
 454         while (size && *buf) {
 455                 size--;
 456                 buf++;
 457         }
 458         if (!size)
 459                 goto free_return;
 460         buf++; size--;
 461         it = cache_tree();
 462
 463         cp = buf;
 464         it->entry_count = strtol(cp, &ep, 10);
 465         if (cp == ep)
 466                 goto free_return;
 467         cp = ep;
 468         subtree_nr = strtol(cp, &ep, 10);
 469         if (cp == ep)
 470                 goto free_return;
 471         while (size && *buf && *buf != '\n') {
 472                 size--;
 473                 buf++;
 474         }
 475         if (!size)
 476                 goto free_return;
 477         buf++; size--;
 478         if (0 <= it->entry_count) {
 479                 if (size < 20)
 480                         goto free_return;
 481                 memcpy(it->sha1, buf, 20);
 482                 buf += 20;
 483                 size -= 20;
 484         }
 485
 486 #if DEBUG
 487         if (0 <= it->entry_count)
 488                 fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
 489                         *buffer, it->entry_count, subtree_nr,
 490                         sha1_to_hex(it->sha1));
 491         else
 492                 fprintf(stderr, "cache-tree <%s> (%d subtrees) invalid\n",
 493                         *buffer, subtree_nr);
 494 #endif
 495
 496         /*
 497          * Just a heuristic -- we do not add directories that often but
 498          * we do not want to have to extend it immediately when we do,
 499          * hence +2.
 500          */
 501         it->subtree_alloc = subtree_nr + 2;
 502         it->down = xcalloc(it->subtree_alloc, sizeof(struct cache_tree_sub *));
 503         for (i = 0; i < subtree_nr; i++) {
 504                 /* read each subtree */
 505                 struct cache_tree *sub;
 506                 struct cache_tree_sub *subtree;
 507                 const char *name = buf;
 508
 509                 sub = read_one(&buf, &size);
 510                 if (!sub)
 511                         goto free_return;
 512                 subtree = cache_tree_sub(it, name);
 513                 subtree->cache_tree = sub;
 514         }
 515         if (subtree_nr != it->subtree_nr)
 516                 die("cache-tree: internal error");
 517         *buffer = buf;
 518         *size_p = size;
 519         return it;
 520
 521  free_return:
 522         cache_tree_free(&it);
 523         return NULL;
 524 }
 525
 526 struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
 527 {
 528         if (buffer[0])
 529                 return NULL; /* not the whole tree */
 530         return read_one(&buffer, &size);
 531 }
 532
 533 struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
 534 {
 535         while (*path) {
 536                 const char *slash;
 537                 struct cache_tree_sub *sub;
 538
 539                 slash = strchr(path, '/');
 540                 if (!slash)
 541                         slash = path + strlen(path);
 542                 /* between path and slash is the name of the
 543                  * subtree to look for.
 544                  */
 545                 sub = find_subtree(it, path, slash - path, 0);
 546                 if (!sub)
 547                         return NULL;
 548                 it = sub->cache_tree;
 549                 if (slash)
 550                         while (*slash && *slash == '/')
 551                                 slash++;
 552                 if (!slash || !*slash)
 553                         return it; /* prefix ended with slashes */
 554                 path = slash;
 555         }
 556         return it;
 557 }