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