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 (!it)
 114                 return;
 115         slash = strchr(path, '/');
 116         it->entry_count = -1;
 117         if (!slash) {
 118                 int pos;
 119                 namelen = strlen(path);
 120                 pos = subtree_pos(it, path, namelen);
 121                 if (0 <= pos) {
 122                         cache_tree_free(&it->down[pos]->cache_tree);
 123                         free(it->down[pos]);
 124                         /* 0 1 2 3 4 5
 125                          *       ^     ^subtree_nr = 6
 126                          *       pos
 127                          * move 4 and 5 up one place (2 entries)
 128                          * 2 = 6 - 3 - 1 = subtree_nr - pos - 1
 129                          */
 130                         memmove(it->down+pos, it->down+pos+1,
 131                                 sizeof(struct cache_tree_sub *) *
 132                                 (it->subtree_nr - pos - 1));
 133                         it->subtree_nr--;
 134                 }
 135                 return;
 136         }
 137         namelen = slash - path;
 138         down = find_subtree(it, path, namelen, 0);
 139         if (down)
 140                 cache_tree_invalidate_path(down->cache_tree, slash + 1);
 141 }
 142
 143 static int verify_cache(struct cache_entry **cache,
 144                         int entries)
 145 {
 146         int i, funny;
 147
 148         /* Verify that the tree is merged */
 149         funny = 0;
 150         for (i = 0; i < entries; i++) {
 151                 struct cache_entry *ce = cache[i];
 152                 if (ce_stage(ce)) {
 153                         if (10 < ++funny) {
 154                                 fprintf(stderr, "...\n");
 155                                 break;
 156                         }
 157                         fprintf(stderr, "%s: unmerged (%s)\n",
 158                                 ce->name, sha1_to_hex(ce->sha1));
 159                 }
 160         }
 161         if (funny)
 162                 return -1;
 163
 164         /* Also verify that the cache does not have path and path/file
 165          * at the same time.  At this point we know the cache has only
 166          * stage 0 entries.
 167          */
 168         funny = 0;
 169         for (i = 0; i < entries - 1; i++) {
 170                 /* path/file always comes after path because of the way
 171                  * the cache is sorted.  Also path can appear only once,
 172                  * which means conflicting one would immediately follow.
 173                  */
 174                 const char *this_name = cache[i]->name;
 175                 const char *next_name = cache[i+1]->name;
 176                 int this_len = strlen(this_name);
 177                 if (this_len < strlen(next_name) &&
 178                     strncmp(this_name, next_name, this_len) == 0 &&
 179                     next_name[this_len] == '/') {
 180                         if (10 < ++funny) {
 181                                 fprintf(stderr, "...\n");
 182                                 break;
 183                         }
 184                         fprintf(stderr, "You have both %s and %s\n",
 185                                 this_name, next_name);
 186                 }
 187         }
 188         if (funny)
 189                 return -1;
 190         return 0;
 191 }
 192
 193 static void discard_unused_subtrees(struct cache_tree *it)
 194 {
 195         struct cache_tree_sub **down = it->down;
 196         int nr = it->subtree_nr;
 197         int dst, src;
 198         for (dst = src = 0; src < nr; src++) {
 199                 struct cache_tree_sub *s = down[src];
 200                 if (s->used)
 201                         down[dst++] = s;
 202                 else {
 203                         cache_tree_free(&s->cache_tree);
 204                         free(s);
 205                         it->subtree_nr--;
 206                 }
 207         }
 208 }
 209
 210 int cache_tree_fully_valid(struct cache_tree *it)
 211 {
 212         int i;
 213         if (!it)
 214                 return 0;
 215         if (it->entry_count < 0 || !has_sha1_file(it->sha1))
 216                 return 0;
 217         for (i = 0; i < it->subtree_nr; i++) {
 218                 if (!cache_tree_fully_valid(it->down[i]->cache_tree))
 219                         return 0;
 220         }
 221         return 1;
 222 }
 223
 224 static int update_one(struct cache_tree *it,
 225                       struct cache_entry **cache,
 226                       int entries,
 227                       const char *base,
 228                       int baselen,
 229                       int missing_ok,
 230                       int dryrun)
 231 {
 232         unsigned long size, offset;
 233         char *buffer;
 234         int i;
 235
 236         if (0 <= it->entry_count && has_sha1_file(it->sha1))
 237                 return it->entry_count;
 238
 239         /*
 240          * We first scan for subtrees and update them; we start by
 241          * marking existing subtrees -- the ones that are unmarked
 242          * should not be in the result.
 243          */
 244         for (i = 0; i < it->subtree_nr; i++)
 245                 it->down[i]->used = 0;
 246
 247         /*
 248          * Find the subtrees and update them.
 249          */
 250         for (i = 0; i < entries; i++) {
 251                 struct cache_entry *ce = cache[i];
 252                 struct cache_tree_sub *sub;
 253                 const char *path, *slash;
 254                 int pathlen, sublen, subcnt;
 255
 256                 path = ce->name;
 257                 pathlen = ce_namelen(ce);
 258                 if (pathlen <= baselen || memcmp(base, path, baselen))
 259                         break; /* at the end of this level */
 260
 261                 slash = strchr(path + baselen, '/');
 262                 if (!slash)
 263                         continue;
 264                 /*
 265                  * a/bbb/c (base = a/, slash = /c)
 266                  * ==>
 267                  * path+baselen = bbb/c, sublen = 3
 268                  */
 269                 sublen = slash - (path + baselen);
 270                 sub = find_subtree(it, path + baselen, sublen, 1);
 271                 if (!sub->cache_tree)
 272                         sub->cache_tree = cache_tree();
 273                 subcnt = update_one(sub->cache_tree,
 274                                     cache + i, entries - i,
 275                                     path,
 276                                     baselen + sublen + 1,
 277                                     missing_ok,
 278                                     dryrun);
 279                 i += subcnt - 1;
 280                 sub->used = 1;
 281         }
 282
 283         discard_unused_subtrees(it);
 284
 285         /*
 286          * Then write out the tree object for this level.
 287          */
 288         size = 8192;
 289         buffer = xmalloc(size);
 290         offset = 0;
 291
 292         for (i = 0; i < entries; i++) {
 293                 struct cache_entry *ce = cache[i];
 294                 struct cache_tree_sub *sub;
 295                 const char *path, *slash;
 296                 int pathlen, entlen;
 297                 const unsigned char *sha1;
 298                 unsigned mode;
 299
 300                 path = ce->name;
 301                 pathlen = ce_namelen(ce);
 302                 if (pathlen <= baselen || memcmp(base, path, baselen))
 303                         break; /* at the end of this level */
 304
 305                 slash = strchr(path + baselen, '/');
 306                 if (slash) {
 307                         entlen = slash - (path + baselen);
 308                         sub = find_subtree(it, path + baselen, entlen, 0);
 309                         if (!sub)
 310                                 die("cache-tree.c: '%.*s' in '%s' not found",
 311                                     entlen, path + baselen, path);
 312                         i += sub->cache_tree->entry_count - 1;
 313                         sha1 = sub->cache_tree->sha1;
 314                         mode = S_IFDIR;
 315                 }
 316                 else {
 317                         sha1 = ce->sha1;
 318                         mode = ntohl(ce->ce_mode);
 319                         entlen = pathlen - baselen;
 320                 }
 321                 if (!missing_ok && !has_sha1_file(sha1))
 322                         return error("invalid object %s", sha1_to_hex(sha1));
 323
 324                 if (!ce->ce_mode)
 325                         continue; /* entry being removed */
 326
 327                 if (size < offset + entlen + 100) {
 328                         size = alloc_nr(offset + entlen + 100);
 329                         buffer = xrealloc(buffer, size);
 330                 }
 331                 offset += sprintf(buffer + offset,
 332                                   "%o %.*s", mode, entlen, path + baselen);
 333                 buffer[offset++] = 0;
 334                 memcpy(buffer + offset, sha1, 20);
 335                 offset += 20;
 336
 337 #if DEBUG
 338                 fprintf(stderr, "cache-tree %o %.*s\n",
 339                         mode, entlen, path + baselen);
 340 #endif
 341         }
 342
 343         if (dryrun) {
 344                 unsigned char hdr[200];
 345                 int hdrlen;
 346                 write_sha1_file_prepare(buffer, offset, tree_type, it->sha1,
 347                                         hdr, &hdrlen);
 348         }
 349         else
 350                 write_sha1_file(buffer, offset, tree_type, it->sha1);
 351         free(buffer);
 352         it->entry_count = i;
 353 #if DEBUG
 354         fprintf(stderr, "cache-tree (%d ent, %d subtree) %s\n",
 355                 it->entry_count, it->subtree_nr,
 356                 sha1_to_hex(it->sha1));
 357 #endif
 358         return i;
 359 }
 360
 361 int cache_tree_update(struct cache_tree *it,
 362                       struct cache_entry **cache,
 363                       int entries,
 364                       int missing_ok,
 365                       int dryrun)
 366 {
 367         int i;
 368         i = verify_cache(cache, entries);
 369         if (i)
 370                 return i;
 371         i = update_one(it, cache, entries, "", 0, missing_ok, dryrun);
 372         if (i < 0)
 373                 return i;
 374         return 0;
 375 }
 376
 377 static void *write_one(struct cache_tree *it,
 378                        char *path,
 379                        int pathlen,
 380                        char *buffer,
 381                        unsigned long *size,
 382                        unsigned long *offset)
 383 {
 384         int i;
 385
 386         /* One "cache-tree" entry consists of the following:
 387          * path (NUL terminated)
 388          * entry_count, subtree_nr ("%d %d\n")
 389          * tree-sha1 (missing if invalid)
 390          * subtree_nr "cache-tree" entries for subtrees.
 391          */
 392         if (*size < *offset + pathlen + 100) {
 393                 *size = alloc_nr(*offset + pathlen + 100);
 394                 buffer = xrealloc(buffer, *size);
 395         }
 396         *offset += sprintf(buffer + *offset, "%.*s%c%d %d\n",
 397                            pathlen, path, 0,
 398                            it->entry_count, it->subtree_nr);
 399
 400 #if DEBUG
 401         if (0 <= it->entry_count)
 402                 fprintf(stderr, "cache-tree <%.*s> (%d ent, %d subtree) %s\n",
 403                         pathlen, path, it->entry_count, it->subtree_nr,
 404                         sha1_to_hex(it->sha1));
 405         else
 406                 fprintf(stderr, "cache-tree <%.*s> (%d subtree) invalid\n",
 407                         pathlen, path, it->subtree_nr);
 408 #endif
 409
 410         if (0 <= it->entry_count) {
 411                 memcpy(buffer + *offset, it->sha1, 20);
 412                 *offset += 20;
 413         }
 414         for (i = 0; i < it->subtree_nr; i++) {
 415                 struct cache_tree_sub *down = it->down[i];
 416                 if (i) {
 417                         struct cache_tree_sub *prev = it->down[i-1];
 418                         if (subtree_name_cmp(down->name, down->namelen,
 419                                              prev->name, prev->namelen) <= 0)
 420                                 die("fatal - unsorted cache subtree");
 421                 }
 422                 buffer = write_one(down->cache_tree, down->name, down->namelen,
 423                                    buffer, size, offset);
 424         }
 425         return buffer;
 426 }
 427
 428 void *cache_tree_write(struct cache_tree *root, unsigned long *size_p)
 429 {
 430         char path[PATH_MAX];
 431         unsigned long size = 8192;
 432         char *buffer = xmalloc(size);
 433
 434         *size_p = 0;
 435         path[0] = 0;
 436         return write_one(root, path, 0, buffer, &size, size_p);
 437 }
 438
 439 static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
 440 {
 441         const char *buf = *buffer;
 442         unsigned long size = *size_p;
 443         struct cache_tree *it;
 444         int i, subtree_nr;
 445
 446         it = NULL;
 447         /* skip name, but make sure name exists */
 448         while (size && *buf) {
 449                 size--;
 450                 buf++;
 451         }
 452         if (!size)
 453                 goto free_return;
 454         buf++; size--;
 455         it = cache_tree();
 456         if (sscanf(buf, "%d %d\n", &it->entry_count, &subtree_nr) != 2)
 457                 goto free_return;
 458         while (size && *buf && *buf != '\n') {
 459                 size--;
 460                 buf++;
 461         }
 462         if (!size)
 463                 goto free_return;
 464         buf++; size--;
 465         if (0 <= it->entry_count) {
 466                 if (size < 20)
 467                         goto free_return;
 468                 memcpy(it->sha1, buf, 20);
 469                 buf += 20;
 470                 size -= 20;
 471         }
 472
 473 #if DEBUG
 474         if (0 <= it->entry_count)
 475                 fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
 476                         *buffer, it->entry_count, subtree_nr,
 477                         sha1_to_hex(it->sha1));
 478         else
 479                 fprintf(stderr, "cache-tree <%s> (%d subtrees) invalid\n",
 480                         *buffer, subtree_nr);
 481 #endif
 482
 483         /*
 484          * Just a heuristic -- we do not add directories that often but
 485          * we do not want to have to extend it immediately when we do,
 486          * hence +2.
 487          */
 488         it->subtree_alloc = subtree_nr + 2;
 489         it->down = xcalloc(it->subtree_alloc, sizeof(struct cache_tree_sub *));
 490         for (i = 0; i < subtree_nr; i++) {
 491                 /* read each subtree */
 492                 struct cache_tree *sub;
 493                 struct cache_tree_sub *subtree;
 494                 const char *name = buf;
 495
 496                 sub = read_one(&buf, &size);
 497                 if (!sub)
 498                         goto free_return;
 499                 subtree = cache_tree_sub(it, name);
 500                 subtree->cache_tree = sub;
 501         }
 502         if (subtree_nr != it->subtree_nr)
 503                 die("cache-tree: internal error");
 504         *buffer = buf;
 505         *size_p = size;
 506         return it;
 507
 508  free_return:
 509         cache_tree_free(&it);
 510         return NULL;
 511 }
 512
 513 struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
 514 {
 515         if (buffer[0])
 516                 return NULL; /* not the whole tree */
 517         return read_one(&buffer, &size);
 518 }