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