tree-walk.c

   1 #include "cache.h"
   2 #include "tree-walk.h"
   3 #include "unpack-trees.h"
   4 #include "dir.h"
   5 #include "tree.h"
   6 #include "pathspec.h"
   7
   8 static const char *get_mode(const char *str, unsigned int *modep)
   9 {
  10         unsigned char c;
  11         unsigned int mode = 0;
  12
  13         if (*str == ' ')
  14                 return NULL;
  15
  16         while ((c = *str++) != ' ') {
  17                 if (c < '0' || c > '7')
  18                         return NULL;
  19                 mode = (mode << 3) + (c - '0');
  20         }
  21         *modep = mode;
  22         return str;
  23 }
  24
  25 static void decode_tree_entry(struct tree_desc *desc, const char *buf, unsigned long size)
  26 {
  27         const char *path;
  28         unsigned int mode, len;
  29
  30         if (size < 24 || buf[size - 21])
  31                 die("corrupt tree file");
  32
  33         path = get_mode(buf, &mode);
  34         if (!path || !*path)
  35                 die("corrupt tree file");
  36         len = strlen(path) + 1;
  37
  38         /* Initialize the descriptor entry */
  39         desc->entry.path = path;
  40         desc->entry.mode = mode;
  41         desc->entry.sha1 = (const unsigned char *)(path + len);
  42 }
  43
  44 void init_tree_desc(struct tree_desc *desc, const void *buffer, unsigned long size)
  45 {
  46         desc->buffer = buffer;
  47         desc->size = size;
  48         if (size)
  49                 decode_tree_entry(desc, buffer, size);
  50 }
  51
  52 void *fill_tree_descriptor(struct tree_desc *desc, const unsigned char *sha1)
  53 {
  54         unsigned long size = 0;
  55         void *buf = NULL;
  56
  57         if (sha1) {
  58                 buf = read_object_with_reference(sha1, tree_type, &size, NULL);
  59                 if (!buf)
  60                         die("unable to read tree %s", sha1_to_hex(sha1));
  61         }
  62         init_tree_desc(desc, buf, size);
  63         return buf;
  64 }
  65
  66 static void entry_clear(struct name_entry *a)
  67 {
  68         memset(a, 0, sizeof(*a));
  69 }
  70
  71 static void entry_extract(struct tree_desc *t, struct name_entry *a)
  72 {
  73         *a = t->entry;
  74 }
  75
  76 void update_tree_entry(struct tree_desc *desc)
  77 {
  78         const void *buf = desc->buffer;
  79         const unsigned char *end = desc->entry.sha1 + 20;
  80         unsigned long size = desc->size;
  81         unsigned long len = end - (const unsigned char *)buf;
  82
  83         if (size < len)
  84                 die("corrupt tree file");
  85         buf = end;
  86         size -= len;
  87         desc->buffer = buf;
  88         desc->size = size;
  89         if (size)
  90                 decode_tree_entry(desc, buf, size);
  91 }
  92
  93 int tree_entry(struct tree_desc *desc, struct name_entry *entry)
  94 {
  95         if (!desc->size)
  96                 return 0;
  97
  98         *entry = desc->entry;
  99         update_tree_entry(desc);
 100         return 1;
 101 }
 102
 103 void setup_traverse_info(struct traverse_info *info, const char *base)
 104 {
 105         int pathlen = strlen(base);
 106         static struct traverse_info dummy;
 107
 108         memset(info, 0, sizeof(*info));
 109         if (pathlen && base[pathlen-1] == '/')
 110                 pathlen--;
 111         info->pathlen = pathlen ? pathlen + 1 : 0;
 112         info->name.path = base;
 113         info->name.sha1 = (void *)(base + pathlen + 1);
 114         if (pathlen)
 115                 info->prev = &dummy;
 116 }
 117
 118 char *make_traverse_path(char *path, const struct traverse_info *info, const struct name_entry *n)
 119 {
 120         int len = tree_entry_len(n);
 121         int pathlen = info->pathlen;
 122
 123         path[pathlen + len] = 0;
 124         for (;;) {
 125                 memcpy(path + pathlen, n->path, len);
 126                 if (!pathlen)
 127                         break;
 128                 path[--pathlen] = '/';
 129                 n = &info->name;
 130                 len = tree_entry_len(n);
 131                 info = info->prev;
 132                 pathlen -= len;
 133         }
 134         return path;
 135 }
 136
 137 struct tree_desc_skip {
 138         struct tree_desc_skip *prev;
 139         const void *ptr;
 140 };
 141
 142 struct tree_desc_x {
 143         struct tree_desc d;
 144         struct tree_desc_skip *skip;
 145 };
 146
 147 static int name_compare(const char *a, int a_len,
 148                         const char *b, int b_len)
 149 {
 150         int len = (a_len < b_len) ? a_len : b_len;
 151         int cmp = memcmp(a, b, len);
 152         if (cmp)
 153                 return cmp;
 154         return (a_len - b_len);
 155 }
 156
 157 static int check_entry_match(const char *a, int a_len, const char *b, int b_len)
 158 {
 159         /*
 160          * The caller wants to pick *a* from a tree or nothing.
 161          * We are looking at *b* in a tree.
 162          *
 163          * (0) If a and b are the same name, we are trivially happy.
 164          *
 165          * There are three possibilities where *a* could be hiding
 166          * behind *b*.
 167          *
 168          * (1) *a* == "t",   *b* == "ab"  i.e. *b* sorts earlier than *a* no
 169          *                                matter what.
 170          * (2) *a* == "t",   *b* == "t-2" and "t" is a subtree in the tree;
 171          * (3) *a* == "t-2", *b* == "t"   and "t-2" is a blob in the tree.
 172          *
 173          * Otherwise we know *a* won't appear in the tree without
 174          * scanning further.
 175          */
 176
 177         int cmp = name_compare(a, a_len, b, b_len);
 178
 179         /* Most common case first -- reading sync'd trees */
 180         if (!cmp)
 181                 return cmp;
 182
 183         if (0 < cmp) {
 184                 /* a comes after b; it does not matter if it is case (3)
 185                 if (b_len < a_len && !memcmp(a, b, b_len) && a[b_len] < '/')
 186                         return 1;
 187                 */
 188                 return 1; /* keep looking */
 189         }
 190
 191         /* b comes after a; are we looking at case (2)? */
 192         if (a_len < b_len && !memcmp(a, b, a_len) && b[a_len] < '/')
 193                 return 1; /* keep looking */
 194
 195         return -1; /* a cannot appear in the tree */
 196 }
 197
 198 /*
 199  * From the extended tree_desc, extract the first name entry, while
 200  * paying attention to the candidate "first" name.  Most importantly,
 201  * when looking for an entry, if there are entries that sorts earlier
 202  * in the tree object representation than that name, skip them and
 203  * process the named entry first.  We will remember that we haven't
 204  * processed the first entry yet, and in the later call skip the
 205  * entry we processed early when update_extended_entry() is called.
 206  *
 207  * E.g. if the underlying tree object has these entries:
 208  *
 209  *    blob    "t-1"
 210  *    blob    "t-2"
 211  *    tree    "t"
 212  *    blob    "t=1"
 213  *
 214  * and the "first" asks for "t", remember that we still need to
 215  * process "t-1" and "t-2" but extract "t".  After processing the
 216  * entry "t" from this call, the caller will let us know by calling
 217  * update_extended_entry() that we can remember "t" has been processed
 218  * already.
 219  */
 220
 221 static void extended_entry_extract(struct tree_desc_x *t,
 222                                    struct name_entry *a,
 223                                    const char *first,
 224                                    int first_len)
 225 {
 226         const char *path;
 227         int len;
 228         struct tree_desc probe;
 229         struct tree_desc_skip *skip;
 230
 231         /*
 232          * Extract the first entry from the tree_desc, but skip the
 233          * ones that we already returned in earlier rounds.
 234          */
 235         while (1) {
 236                 if (!t->d.size) {
 237                         entry_clear(a);
 238                         break; /* not found */
 239                 }
 240                 entry_extract(&t->d, a);
 241                 for (skip = t->skip; skip; skip = skip->prev)
 242                         if (a->path == skip->ptr)
 243                                 break; /* found */
 244                 if (!skip)
 245                         break;
 246                 /* We have processed this entry already. */
 247                 update_tree_entry(&t->d);
 248         }
 249
 250         if (!first || !a->path)
 251                 return;
 252
 253         /*
 254          * The caller wants "first" from this tree, or nothing.
 255          */
 256         path = a->path;
 257         len = tree_entry_len(a);
 258         switch (check_entry_match(first, first_len, path, len)) {
 259         case -1:
 260                 entry_clear(a);
 261         case 0:
 262                 return;
 263         default:
 264                 break;
 265         }
 266
 267         /*
 268          * We need to look-ahead -- we suspect that a subtree whose
 269          * name is "first" may be hiding behind the current entry "path".
 270          */
 271         probe = t->d;
 272         while (probe.size) {
 273                 entry_extract(&probe, a);
 274                 path = a->path;
 275                 len = tree_entry_len(a);
 276                 switch (check_entry_match(first, first_len, path, len)) {
 277                 case -1:
 278                         entry_clear(a);
 279                 case 0:
 280                         return;
 281                 default:
 282                         update_tree_entry(&probe);
 283                         break;
 284                 }
 285                 /* keep looking */
 286         }
 287         entry_clear(a);
 288 }
 289
 290 static void update_extended_entry(struct tree_desc_x *t, struct name_entry *a)
 291 {
 292         if (t->d.entry.path == a->path) {
 293                 update_tree_entry(&t->d);
 294         } else {
 295                 /* we have returned this entry early */
 296                 struct tree_desc_skip *skip = xmalloc(sizeof(*skip));
 297                 skip->ptr = a->path;
 298                 skip->prev = t->skip;
 299                 t->skip = skip;
 300         }
 301 }
 302
 303 static void free_extended_entry(struct tree_desc_x *t)
 304 {
 305         struct tree_desc_skip *p, *s;
 306
 307         for (s = t->skip; s; s = p) {
 308                 p = s->prev;
 309                 free(s);
 310         }
 311 }
 312
 313 static inline int prune_traversal(struct name_entry *e,
 314                                   struct traverse_info *info,
 315                                   struct strbuf *base,
 316                                   int still_interesting)
 317 {
 318         if (!info->pathspec || still_interesting == 2)
 319                 return 2;
 320         if (still_interesting < 0)
 321                 return still_interesting;
 322         return tree_entry_interesting(e, base, 0, info->pathspec);
 323 }
 324
 325 int traverse_trees(int n, struct tree_desc *t, struct traverse_info *info)
 326 {
 327         int ret = 0;
 328         int error = 0;
 329         struct name_entry *entry = xmalloc(n*sizeof(*entry));
 330         int i;
 331         struct tree_desc_x *tx = xcalloc(n, sizeof(*tx));
 332         struct strbuf base = STRBUF_INIT;
 333         int interesting = 1;
 334
 335         for (i = 0; i < n; i++)
 336                 tx[i].d = t[i];
 337
 338         if (info->prev) {
 339                 strbuf_grow(&base, info->pathlen);
 340                 make_traverse_path(base.buf, info->prev, &info->name);
 341                 base.buf[info->pathlen-1] = '/';
 342                 strbuf_setlen(&base, info->pathlen);
 343         }
 344         for (;;) {
 345                 unsigned long mask, dirmask;
 346                 const char *first = NULL;
 347                 int first_len = 0;
 348                 struct name_entry *e = NULL;
 349                 int len;
 350
 351                 for (i = 0; i < n; i++) {
 352                         e = entry + i;
 353                         extended_entry_extract(tx + i, e, NULL, 0);
 354                 }
 355
 356                 /*
 357                  * A tree may have "t-2" at the current location even
 358                  * though it may have "t" that is a subtree behind it,
 359                  * and another tree may return "t".  We want to grab
 360                  * all "t" from all trees to match in such a case.
 361                  */
 362                 for (i = 0; i < n; i++) {
 363                         e = entry + i;
 364                         if (!e->path)
 365                                 continue;
 366                         len = tree_entry_len(e);
 367                         if (!first) {
 368                                 first = e->path;
 369                                 first_len = len;
 370                                 continue;
 371                         }
 372                         if (name_compare(e->path, len, first, first_len) < 0) {
 373                                 first = e->path;
 374                                 first_len = len;
 375                         }
 376                 }
 377
 378                 if (first) {
 379                         for (i = 0; i < n; i++) {
 380                                 e = entry + i;
 381                                 extended_entry_extract(tx + i, e, first, first_len);
 382                                 /* Cull the ones that are not the earliest */
 383                                 if (!e->path)
 384                                         continue;
 385                                 len = tree_entry_len(e);
 386                                 if (name_compare(e->path, len, first, first_len))
 387                                         entry_clear(e);
 388                         }
 389                 }
 390
 391                 /* Now we have in entry[i] the earliest name from the trees */
 392                 mask = 0;
 393                 dirmask = 0;
 394                 for (i = 0; i < n; i++) {
 395                         if (!entry[i].path)
 396                                 continue;
 397                         mask |= 1ul << i;
 398                         if (S_ISDIR(entry[i].mode))
 399                                 dirmask |= 1ul << i;
 400                         e = &entry[i];
 401                 }
 402                 if (!mask)
 403                         break;
 404                 interesting = prune_traversal(e, info, &base, interesting);
 405                 if (interesting < 0)
 406                         break;
 407                 if (interesting) {
 408                         ret = info->fn(n, mask, dirmask, entry, info);
 409                         if (ret < 0) {
 410                                 error = ret;
 411                                 if (!info->show_all_errors)
 412                                         break;
 413                         }
 414                         mask &= ret;
 415                 }
 416                 ret = 0;
 417                 for (i = 0; i < n; i++)
 418                         if (mask & (1ul << i))
 419                                 update_extended_entry(tx + i, entry + i);
 420         }
 421         free(entry);
 422         for (i = 0; i < n; i++)
 423                 free_extended_entry(tx + i);
 424         free(tx);
 425         strbuf_release(&base);
 426         return error;
 427 }
 428
 429 static int find_tree_entry(struct tree_desc *t, const char *name, unsigned char *result, unsigned *mode)
 430 {
 431         int namelen = strlen(name);
 432         while (t->size) {
 433                 const char *entry;
 434                 const unsigned char *sha1;
 435                 int entrylen, cmp;
 436
 437                 sha1 = tree_entry_extract(t, &entry, mode);
 438                 entrylen = tree_entry_len(&t->entry);
 439                 update_tree_entry(t);
 440                 if (entrylen > namelen)
 441                         continue;
 442                 cmp = memcmp(name, entry, entrylen);
 443                 if (cmp > 0)
 444                         continue;
 445                 if (cmp < 0)
 446                         break;
 447                 if (entrylen == namelen) {
 448                         hashcpy(result, sha1);
 449                         return 0;
 450                 }
 451                 if (name[entrylen] != '/')
 452                         continue;
 453                 if (!S_ISDIR(*mode))
 454                         break;
 455                 if (++entrylen == namelen) {
 456                         hashcpy(result, sha1);
 457                         return 0;
 458                 }
 459                 return get_tree_entry(sha1, name + entrylen, result, mode);
 460         }
 461         return -1;
 462 }
 463
 464 int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned char *sha1, unsigned *mode)
 465 {
 466         int retval;
 467         void *tree;
 468         unsigned long size;
 469         unsigned char root[20];
 470
 471         tree = read_object_with_reference(tree_sha1, tree_type, &size, root);
 472         if (!tree)
 473                 return -1;
 474
 475         if (name[0] == '\0') {
 476                 hashcpy(sha1, root);
 477                 free(tree);
 478                 return 0;
 479         }
 480
 481         if (!size) {
 482                 retval = -1;
 483         } else {
 484                 struct tree_desc t;
 485                 init_tree_desc(&t, tree, size);
 486                 retval = find_tree_entry(&t, name, sha1, mode);
 487         }
 488         free(tree);
 489         return retval;
 490 }
 491
 492 static int match_entry(const struct name_entry *entry, int pathlen,
 493                        const char *match, int matchlen,
 494                        enum interesting *never_interesting)
 495 {
 496         int m = -1; /* signals that we haven't called strncmp() */
 497
 498         if (*never_interesting != entry_not_interesting) {
 499                 /*
 500                  * We have not seen any match that sorts later
 501                  * than the current path.
 502                  */
 503
 504                 /*
 505                  * Does match sort strictly earlier than path
 506                  * with their common parts?
 507                  */
 508                 m = strncmp(match, entry->path,
 509                             (matchlen < pathlen) ? matchlen : pathlen);
 510                 if (m < 0)
 511                         return 0;
 512
 513                 /*
 514                  * If we come here even once, that means there is at
 515                  * least one pathspec that would sort equal to or
 516                  * later than the path we are currently looking at.
 517                  * In other words, if we have never reached this point
 518                  * after iterating all pathspecs, it means all
 519                  * pathspecs are either outside of base, or inside the
 520                  * base but sorts strictly earlier than the current
 521                  * one.  In either case, they will never match the
 522                  * subsequent entries.  In such a case, we initialized
 523                  * the variable to -1 and that is what will be
 524                  * returned, allowing the caller to terminate early.
 525                  */
 526                 *never_interesting = entry_not_interesting;
 527         }
 528
 529         if (pathlen > matchlen)
 530                 return 0;
 531
 532         if (matchlen > pathlen) {
 533                 if (match[pathlen] != '/')
 534                         return 0;
 535                 if (!S_ISDIR(entry->mode))
 536                         return 0;
 537         }
 538
 539         if (m == -1)
 540                 /*
 541                  * we cheated and did not do strncmp(), so we do
 542                  * that here.
 543                  */
 544                 m = strncmp(match, entry->path, pathlen);
 545
 546         /*
 547          * If common part matched earlier then it is a hit,
 548          * because we rejected the case where path is not a
 549          * leading directory and is shorter than match.
 550          */
 551         if (!m)
 552                 return 1;
 553
 554         return 0;
 555 }
 556
 557 static int match_dir_prefix(const char *base,
 558                             const char *match, int matchlen)
 559 {
 560         if (strncmp(base, match, matchlen))
 561                 return 0;
 562
 563         /*
 564          * If the base is a subdirectory of a path which
 565          * was specified, all of them are interesting.
 566          */
 567         if (!matchlen ||
 568             base[matchlen] == '/' ||
 569             match[matchlen - 1] == '/')
 570                 return 1;
 571
 572         /* Just a random prefix match */
 573         return 0;
 574 }
 575
 576 /*
 577  * Perform matching on the leading non-wildcard part of
 578  * pathspec. item->nowildcard_len must be greater than zero. Return
 579  * non-zero if base is matched.
 580  */
 581 static int match_wildcard_base(const struct pathspec_item *item,
 582                                const char *base, int baselen,
 583                                int *matched)
 584 {
 585         const char *match = item->match;
 586         /* the wildcard part is not considered in this function */
 587         int matchlen = item->nowildcard_len;
 588
 589         if (baselen) {
 590                 int dirlen;
 591                 /*
 592                  * Return early if base is longer than the
 593                  * non-wildcard part but it does not match.
 594                  */
 595                 if (baselen >= matchlen) {
 596                         *matched = matchlen;
 597                         return !strncmp(base, match, matchlen);
 598                 }
 599
 600                 dirlen = matchlen;
 601                 while (dirlen && match[dirlen - 1] != '/')
 602                         dirlen--;
 603
 604                 /*
 605                  * Return early if base is shorter than the
 606                  * non-wildcard part but it does not match. Note that
 607                  * base ends with '/' so we are sure it really matches
 608                  * directory
 609                  */
 610                 if (strncmp(base, match, baselen))
 611                         return 0;
 612                 *matched = baselen;
 613         } else
 614                 *matched = 0;
 615         /*
 616          * we could have checked entry against the non-wildcard part
 617          * that is not in base and does similar never_interesting
 618          * optimization as in match_entry. For now just be happy with
 619          * base comparison.
 620          */
 621         return entry_interesting;
 622 }
 623
 624 /*
 625  * Is a tree entry interesting given the pathspec we have?
 626  *
 627  * Pre-condition: either baselen == base_offset (i.e. empty path)
 628  * or base[baselen-1] == '/' (i.e. with trailing slash).
 629  */
 630 enum interesting tree_entry_interesting(const struct name_entry *entry,
 631                                         struct strbuf *base, int base_offset,
 632                                         const struct pathspec *ps)
 633 {
 634         int i;
 635         int pathlen, baselen = base->len - base_offset;
 636         enum interesting never_interesting = ps->has_wildcard ?
 637                 entry_not_interesting : all_entries_not_interesting;
 638
 639         if (!ps->nr) {
 640                 if (!ps->recursive || ps->max_depth == -1)
 641                         return all_entries_interesting;
 642                 return within_depth(base->buf + base_offset, baselen,
 643                                     !!S_ISDIR(entry->mode),
 644                                     ps->max_depth) ?
 645                         entry_interesting : entry_not_interesting;
 646         }
 647
 648         pathlen = tree_entry_len(entry);
 649
 650         for (i = ps->nr - 1; i >= 0; i--) {
 651                 const struct pathspec_item *item = ps->items+i;
 652                 const char *match = item->match;
 653                 const char *base_str = base->buf + base_offset;
 654                 int matchlen = item->len, matched = 0;
 655
 656                 if (baselen >= matchlen) {
 657                         /* If it doesn't match, move along... */
 658                         if (!match_dir_prefix(base_str, match, matchlen))
 659                                 goto match_wildcards;
 660
 661                         if (!ps->recursive || ps->max_depth == -1)
 662                                 return all_entries_interesting;
 663
 664                         return within_depth(base_str + matchlen + 1,
 665                                             baselen - matchlen - 1,
 666                                             !!S_ISDIR(entry->mode),
 667                                             ps->max_depth) ?
 668                                 entry_interesting : entry_not_interesting;
 669                 }
 670
 671                 /* Either there must be no base, or the base must match. */
 672                 if (baselen == 0 || !strncmp(base_str, match, baselen)) {
 673                         if (match_entry(entry, pathlen,
 674                                         match + baselen, matchlen - baselen,
 675                                         &never_interesting))
 676                                 return entry_interesting;
 677
 678                         if (item->nowildcard_len < item->len) {
 679                                 if (!git_fnmatch(match + baselen, entry->path,
 680                                                  item->flags & PATHSPEC_ONESTAR ? GFNM_ONESTAR : 0,
 681                                                  item->nowildcard_len - baselen))
 682                                         return entry_interesting;
 683
 684                                 /*
 685                                  * Match all directories. We'll try to
 686                                  * match files later on.
 687                                  */
 688                                 if (ps->recursive && S_ISDIR(entry->mode))
 689                                         return entry_interesting;
 690                         }
 691
 692                         continue;
 693                 }
 694
 695 match_wildcards:
 696                 if (item->nowildcard_len == item->len)
 697                         continue;
 698
 699                 if (item->nowildcard_len &&
 700                     !match_wildcard_base(item, base_str, baselen, &matched))
 701                         return entry_not_interesting;
 702
 703                 /*
 704                  * Concatenate base and entry->path into one and do
 705                  * fnmatch() on it.
 706                  *
 707                  * While we could avoid concatenation in certain cases
 708                  * [1], which saves a memcpy and potentially a
 709                  * realloc, it turns out not worth it. Measurement on
 710                  * linux-2.6 does not show any clear improvements,
 711                  * partly because of the nowildcard_len optimization
 712                  * in git_fnmatch(). Avoid micro-optimizations here.
 713                  *
 714                  * [1] if match_wildcard_base() says the base
 715                  * directory is already matched, we only need to match
 716                  * the rest, which is shorter so _in theory_ faster.
 717                  */
 718
 719                 strbuf_add(base, entry->path, pathlen);
 720
 721                 if (!git_fnmatch(match, base->buf + base_offset,
 722                                  item->flags & PATHSPEC_ONESTAR ? GFNM_ONESTAR : 0,
 723                                  item->nowildcard_len)) {
 724                         strbuf_setlen(base, base_offset + baselen);
 725                         return entry_interesting;
 726                 }
 727                 strbuf_setlen(base, base_offset + baselen);
 728
 729                 /*
 730                  * Match all directories. We'll try to match files
 731                  * later on.
 732                  * max_depth is ignored but we may consider support it
 733                  * in future, see
 734                  * http://thread.gmane.org/gmane.comp.version-control.git/163757/focus=163840
 735                  */
 736                 if (ps->recursive && S_ISDIR(entry->mode))
 737                         return entry_interesting;
 738         }
 739         return never_interesting; /* No matches */
 740 }