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 = canon_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 check_entry_match(const char *a, int a_len, const char *b, int b_len)
 148 {
 149         /*
 150          * The caller wants to pick *a* from a tree or nothing.
 151          * We are looking at *b* in a tree.
 152          *
 153          * (0) If a and b are the same name, we are trivially happy.
 154          *
 155          * There are three possibilities where *a* could be hiding
 156          * behind *b*.
 157          *
 158          * (1) *a* == "t",   *b* == "ab"  i.e. *b* sorts earlier than *a* no
 159          *                                matter what.
 160          * (2) *a* == "t",   *b* == "t-2" and "t" is a subtree in the tree;
 161          * (3) *a* == "t-2", *b* == "t"   and "t-2" is a blob in the tree.
 162          *
 163          * Otherwise we know *a* won't appear in the tree without
 164          * scanning further.
 165          */
 166
 167         int cmp = name_compare(a, a_len, b, b_len);
 168
 169         /* Most common case first -- reading sync'd trees */
 170         if (!cmp)
 171                 return cmp;
 172
 173         if (0 < cmp) {
 174                 /* a comes after b; it does not matter if it is case (3)
 175                 if (b_len < a_len && !memcmp(a, b, b_len) && a[b_len] < '/')
 176                         return 1;
 177                 */
 178                 return 1; /* keep looking */
 179         }
 180
 181         /* b comes after a; are we looking at case (2)? */
 182         if (a_len < b_len && !memcmp(a, b, a_len) && b[a_len] < '/')
 183                 return 1; /* keep looking */
 184
 185         return -1; /* a cannot appear in the tree */
 186 }
 187
 188 /*
 189  * From the extended tree_desc, extract the first name entry, while
 190  * paying attention to the candidate "first" name.  Most importantly,
 191  * when looking for an entry, if there are entries that sorts earlier
 192  * in the tree object representation than that name, skip them and
 193  * process the named entry first.  We will remember that we haven't
 194  * processed the first entry yet, and in the later call skip the
 195  * entry we processed early when update_extended_entry() is called.
 196  *
 197  * E.g. if the underlying tree object has these entries:
 198  *
 199  *    blob    "t-1"
 200  *    blob    "t-2"
 201  *    tree    "t"
 202  *    blob    "t=1"
 203  *
 204  * and the "first" asks for "t", remember that we still need to
 205  * process "t-1" and "t-2" but extract "t".  After processing the
 206  * entry "t" from this call, the caller will let us know by calling
 207  * update_extended_entry() that we can remember "t" has been processed
 208  * already.
 209  */
 210
 211 static void extended_entry_extract(struct tree_desc_x *t,
 212                                    struct name_entry *a,
 213                                    const char *first,
 214                                    int first_len)
 215 {
 216         const char *path;
 217         int len;
 218         struct tree_desc probe;
 219         struct tree_desc_skip *skip;
 220
 221         /*
 222          * Extract the first entry from the tree_desc, but skip the
 223          * ones that we already returned in earlier rounds.
 224          */
 225         while (1) {
 226                 if (!t->d.size) {
 227                         entry_clear(a);
 228                         break; /* not found */
 229                 }
 230                 entry_extract(&t->d, a);
 231                 for (skip = t->skip; skip; skip = skip->prev)
 232                         if (a->path == skip->ptr)
 233                                 break; /* found */
 234                 if (!skip)
 235                         break;
 236                 /* We have processed this entry already. */
 237                 update_tree_entry(&t->d);
 238         }
 239
 240         if (!first || !a->path)
 241                 return;
 242
 243         /*
 244          * The caller wants "first" from this tree, or nothing.
 245          */
 246         path = a->path;
 247         len = tree_entry_len(a);
 248         switch (check_entry_match(first, first_len, path, len)) {
 249         case -1:
 250                 entry_clear(a);
 251         case 0:
 252                 return;
 253         default:
 254                 break;
 255         }
 256
 257         /*
 258          * We need to look-ahead -- we suspect that a subtree whose
 259          * name is "first" may be hiding behind the current entry "path".
 260          */
 261         probe = t->d;
 262         while (probe.size) {
 263                 entry_extract(&probe, a);
 264                 path = a->path;
 265                 len = tree_entry_len(a);
 266                 switch (check_entry_match(first, first_len, path, len)) {
 267                 case -1:
 268                         entry_clear(a);
 269                 case 0:
 270                         return;
 271                 default:
 272                         update_tree_entry(&probe);
 273                         break;
 274                 }
 275                 /* keep looking */
 276         }
 277         entry_clear(a);
 278 }
 279
 280 static void update_extended_entry(struct tree_desc_x *t, struct name_entry *a)
 281 {
 282         if (t->d.entry.path == a->path) {
 283                 update_tree_entry(&t->d);
 284         } else {
 285                 /* we have returned this entry early */
 286                 struct tree_desc_skip *skip = xmalloc(sizeof(*skip));
 287                 skip->ptr = a->path;
 288                 skip->prev = t->skip;
 289                 t->skip = skip;
 290         }
 291 }
 292
 293 static void free_extended_entry(struct tree_desc_x *t)
 294 {
 295         struct tree_desc_skip *p, *s;
 296
 297         for (s = t->skip; s; s = p) {
 298                 p = s->prev;
 299                 free(s);
 300         }
 301 }
 302
 303 static inline int prune_traversal(struct name_entry *e,
 304                                   struct traverse_info *info,
 305                                   struct strbuf *base,
 306                                   int still_interesting)
 307 {
 308         if (!info->pathspec || still_interesting == 2)
 309                 return 2;
 310         if (still_interesting < 0)
 311                 return still_interesting;
 312         return tree_entry_interesting(e, base, 0, info->pathspec);
 313 }
 314
 315 int traverse_trees(int n, struct tree_desc *t, struct traverse_info *info)
 316 {
 317         int error = 0;
 318         struct name_entry *entry = xmalloc(n*sizeof(*entry));
 319         int i;
 320         struct tree_desc_x *tx = xcalloc(n, sizeof(*tx));
 321         struct strbuf base = STRBUF_INIT;
 322         int interesting = 1;
 323
 324         for (i = 0; i < n; i++)
 325                 tx[i].d = t[i];
 326
 327         if (info->prev) {
 328                 strbuf_grow(&base, info->pathlen);
 329                 make_traverse_path(base.buf, info->prev, &info->name);
 330                 base.buf[info->pathlen-1] = '/';
 331                 strbuf_setlen(&base, info->pathlen);
 332         }
 333         for (;;) {
 334                 int trees_used;
 335                 unsigned long mask, dirmask;
 336                 const char *first = NULL;
 337                 int first_len = 0;
 338                 struct name_entry *e = NULL;
 339                 int len;
 340
 341                 for (i = 0; i < n; i++) {
 342                         e = entry + i;
 343                         extended_entry_extract(tx + i, e, NULL, 0);
 344                 }
 345
 346                 /*
 347                  * A tree may have "t-2" at the current location even
 348                  * though it may have "t" that is a subtree behind it,
 349                  * and another tree may return "t".  We want to grab
 350                  * all "t" from all trees to match in such a case.
 351                  */
 352                 for (i = 0; i < n; i++) {
 353                         e = entry + i;
 354                         if (!e->path)
 355                                 continue;
 356                         len = tree_entry_len(e);
 357                         if (!first) {
 358                                 first = e->path;
 359                                 first_len = len;
 360                                 continue;
 361                         }
 362                         if (name_compare(e->path, len, first, first_len) < 0) {
 363                                 first = e->path;
 364                                 first_len = len;
 365                         }
 366                 }
 367
 368                 if (first) {
 369                         for (i = 0; i < n; i++) {
 370                                 e = entry + i;
 371                                 extended_entry_extract(tx + i, e, first, first_len);
 372                                 /* Cull the ones that are not the earliest */
 373                                 if (!e->path)
 374                                         continue;
 375                                 len = tree_entry_len(e);
 376                                 if (name_compare(e->path, len, first, first_len))
 377                                         entry_clear(e);
 378                         }
 379                 }
 380
 381                 /* Now we have in entry[i] the earliest name from the trees */
 382                 mask = 0;
 383                 dirmask = 0;
 384                 for (i = 0; i < n; i++) {
 385                         if (!entry[i].path)
 386                                 continue;
 387                         mask |= 1ul << i;
 388                         if (S_ISDIR(entry[i].mode))
 389                                 dirmask |= 1ul << i;
 390                         e = &entry[i];
 391                 }
 392                 if (!mask)
 393                         break;
 394                 interesting = prune_traversal(e, info, &base, interesting);
 395                 if (interesting < 0)
 396                         break;
 397                 if (interesting) {
 398                         trees_used = info->fn(n, mask, dirmask, entry, info);
 399                         if (trees_used < 0) {
 400                                 error = trees_used;
 401                                 if (!info->show_all_errors)
 402                                         break;
 403                         }
 404                         mask &= trees_used;
 405                 }
 406                 for (i = 0; i < n; i++)
 407                         if (mask & (1ul << i))
 408                                 update_extended_entry(tx + i, entry + i);
 409         }
 410         free(entry);
 411         for (i = 0; i < n; i++)
 412                 free_extended_entry(tx + i);
 413         free(tx);
 414         strbuf_release(&base);
 415         return error;
 416 }
 417
 418 static int find_tree_entry(struct tree_desc *t, const char *name, unsigned char *result, unsigned *mode)
 419 {
 420         int namelen = strlen(name);
 421         while (t->size) {
 422                 const char *entry;
 423                 const unsigned char *sha1;
 424                 int entrylen, cmp;
 425
 426                 sha1 = tree_entry_extract(t, &entry, mode);
 427                 entrylen = tree_entry_len(&t->entry);
 428                 update_tree_entry(t);
 429                 if (entrylen > namelen)
 430                         continue;
 431                 cmp = memcmp(name, entry, entrylen);
 432                 if (cmp > 0)
 433                         continue;
 434                 if (cmp < 0)
 435                         break;
 436                 if (entrylen == namelen) {
 437                         hashcpy(result, sha1);
 438                         return 0;
 439                 }
 440                 if (name[entrylen] != '/')
 441                         continue;
 442                 if (!S_ISDIR(*mode))
 443                         break;
 444                 if (++entrylen == namelen) {
 445                         hashcpy(result, sha1);
 446                         return 0;
 447                 }
 448                 return get_tree_entry(sha1, name + entrylen, result, mode);
 449         }
 450         return -1;
 451 }
 452
 453 int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned char *sha1, unsigned *mode)
 454 {
 455         int retval;
 456         void *tree;
 457         unsigned long size;
 458         unsigned char root[20];
 459
 460         tree = read_object_with_reference(tree_sha1, tree_type, &size, root);
 461         if (!tree)
 462                 return -1;
 463
 464         if (name[0] == '\0') {
 465                 hashcpy(sha1, root);
 466                 free(tree);
 467                 return 0;
 468         }
 469
 470         if (!size) {
 471                 retval = -1;
 472         } else {
 473                 struct tree_desc t;
 474                 init_tree_desc(&t, tree, size);
 475                 retval = find_tree_entry(&t, name, sha1, mode);
 476         }
 477         free(tree);
 478         return retval;
 479 }
 480
 481 static int match_entry(const struct pathspec_item *item,
 482                        const struct name_entry *entry, int pathlen,
 483                        const char *match, int matchlen,
 484                        enum interesting *never_interesting)
 485 {
 486         int m = -1; /* signals that we haven't called strncmp() */
 487
 488         if (item->magic & PATHSPEC_ICASE)
 489                 /*
 490                  * "Never interesting" trick requires exact
 491                  * matching. We could do something clever with inexact
 492                  * matching, but it's trickier (and not to forget that
 493                  * strcasecmp is locale-dependent, at least in
 494                  * glibc). Just disable it for now. It can't be worse
 495                  * than the wildcard's codepath of '[Tt][Hi][Is][Ss]'
 496                  * pattern.
 497                  */
 498                 *never_interesting = entry_not_interesting;
 499         else if (*never_interesting != entry_not_interesting) {
 500                 /*
 501                  * We have not seen any match that sorts later
 502                  * than the current path.
 503                  */
 504
 505                 /*
 506                  * Does match sort strictly earlier than path
 507                  * with their common parts?
 508                  */
 509                 m = strncmp(match, entry->path,
 510                             (matchlen < pathlen) ? matchlen : pathlen);
 511                 if (m < 0)
 512                         return 0;
 513
 514                 /*
 515                  * If we come here even once, that means there is at
 516                  * least one pathspec that would sort equal to or
 517                  * later than the path we are currently looking at.
 518                  * In other words, if we have never reached this point
 519                  * after iterating all pathspecs, it means all
 520                  * pathspecs are either outside of base, or inside the
 521                  * base but sorts strictly earlier than the current
 522                  * one.  In either case, they will never match the
 523                  * subsequent entries.  In such a case, we initialized
 524                  * the variable to -1 and that is what will be
 525                  * returned, allowing the caller to terminate early.
 526                  */
 527                 *never_interesting = entry_not_interesting;
 528         }
 529
 530         if (pathlen > matchlen)
 531                 return 0;
 532
 533         if (matchlen > pathlen) {
 534                 if (match[pathlen] != '/')
 535                         return 0;
 536                 if (!S_ISDIR(entry->mode) && !S_ISGITLINK(entry->mode))
 537                         return 0;
 538         }
 539
 540         if (m == -1)
 541                 /*
 542                  * we cheated and did not do strncmp(), so we do
 543                  * that here.
 544                  */
 545                 m = ps_strncmp(item, match, entry->path, pathlen);
 546
 547         /*
 548          * If common part matched earlier then it is a hit,
 549          * because we rejected the case where path is not a
 550          * leading directory and is shorter than match.
 551          */
 552         if (!m)
 553                 /*
 554                  * match_entry does not check if the prefix part is
 555                  * matched case-sensitively. If the entry is a
 556                  * directory and part of prefix, it'll be rematched
 557                  * eventually by basecmp with special treatment for
 558                  * the prefix.
 559                  */
 560                 return 1;
 561
 562         return 0;
 563 }
 564
 565 /* :(icase)-aware string compare */
 566 static int basecmp(const struct pathspec_item *item,
 567                    const char *base, const char *match, int len)
 568 {
 569         if (item->magic & PATHSPEC_ICASE) {
 570                 int ret, n = len > item->prefix ? item->prefix : len;
 571                 ret = strncmp(base, match, n);
 572                 if (ret)
 573                         return ret;
 574                 base += n;
 575                 match += n;
 576                 len -= n;
 577         }
 578         return ps_strncmp(item, base, match, len);
 579 }
 580
 581 static int match_dir_prefix(const struct pathspec_item *item,
 582                             const char *base,
 583                             const char *match, int matchlen)
 584 {
 585         if (basecmp(item, base, match, matchlen))
 586                 return 0;
 587
 588         /*
 589          * If the base is a subdirectory of a path which
 590          * was specified, all of them are interesting.
 591          */
 592         if (!matchlen ||
 593             base[matchlen] == '/' ||
 594             match[matchlen - 1] == '/')
 595                 return 1;
 596
 597         /* Just a random prefix match */
 598         return 0;
 599 }
 600
 601 /*
 602  * Perform matching on the leading non-wildcard part of
 603  * pathspec. item->nowildcard_len must be greater than zero. Return
 604  * non-zero if base is matched.
 605  */
 606 static int match_wildcard_base(const struct pathspec_item *item,
 607                                const char *base, int baselen,
 608                                int *matched)
 609 {
 610         const char *match = item->match;
 611         /* the wildcard part is not considered in this function */
 612         int matchlen = item->nowildcard_len;
 613
 614         if (baselen) {
 615                 int dirlen;
 616                 /*
 617                  * Return early if base is longer than the
 618                  * non-wildcard part but it does not match.
 619                  */
 620                 if (baselen >= matchlen) {
 621                         *matched = matchlen;
 622                         return !basecmp(item, base, match, matchlen);
 623                 }
 624
 625                 dirlen = matchlen;
 626                 while (dirlen && match[dirlen - 1] != '/')
 627                         dirlen--;
 628
 629                 /*
 630                  * Return early if base is shorter than the
 631                  * non-wildcard part but it does not match. Note that
 632                  * base ends with '/' so we are sure it really matches
 633                  * directory
 634                  */
 635                 if (basecmp(item, base, match, baselen))
 636                         return 0;
 637                 *matched = baselen;
 638         } else
 639                 *matched = 0;
 640         /*
 641          * we could have checked entry against the non-wildcard part
 642          * that is not in base and does similar never_interesting
 643          * optimization as in match_entry. For now just be happy with
 644          * base comparison.
 645          */
 646         return entry_interesting;
 647 }
 648
 649 /*
 650  * Is a tree entry interesting given the pathspec we have?
 651  *
 652  * Pre-condition: either baselen == base_offset (i.e. empty path)
 653  * or base[baselen-1] == '/' (i.e. with trailing slash).
 654  */
 655 static enum interesting do_match(const struct name_entry *entry,
 656                                  struct strbuf *base, int base_offset,
 657                                  const struct pathspec *ps,
 658                                  int exclude)
 659 {
 660         int i;
 661         int pathlen, baselen = base->len - base_offset;
 662         enum interesting never_interesting = ps->has_wildcard ?
 663                 entry_not_interesting : all_entries_not_interesting;
 664
 665         GUARD_PATHSPEC(ps,
 666                        PATHSPEC_FROMTOP |
 667                        PATHSPEC_MAXDEPTH |
 668                        PATHSPEC_LITERAL |
 669                        PATHSPEC_GLOB |
 670                        PATHSPEC_ICASE |
 671                        PATHSPEC_EXCLUDE);
 672
 673         if (!ps->nr) {
 674                 if (!ps->recursive ||
 675                     !(ps->magic & PATHSPEC_MAXDEPTH) ||
 676                     ps->max_depth == -1)
 677                         return all_entries_interesting;
 678                 return within_depth(base->buf + base_offset, baselen,
 679                                     !!S_ISDIR(entry->mode),
 680                                     ps->max_depth) ?
 681                         entry_interesting : entry_not_interesting;
 682         }
 683
 684         pathlen = tree_entry_len(entry);
 685
 686         for (i = ps->nr - 1; i >= 0; i--) {
 687                 const struct pathspec_item *item = ps->items+i;
 688                 const char *match = item->match;
 689                 const char *base_str = base->buf + base_offset;
 690                 int matchlen = item->len, matched = 0;
 691
 692                 if ((!exclude &&   item->magic & PATHSPEC_EXCLUDE) ||
 693                     ( exclude && !(item->magic & PATHSPEC_EXCLUDE)))
 694                         continue;
 695
 696                 if (baselen >= matchlen) {
 697                         /* If it doesn't match, move along... */
 698                         if (!match_dir_prefix(item, base_str, match, matchlen))
 699                                 goto match_wildcards;
 700
 701                         if (!ps->recursive ||
 702                             !(ps->magic & PATHSPEC_MAXDEPTH) ||
 703                             ps->max_depth == -1)
 704                                 return all_entries_interesting;
 705
 706                         return within_depth(base_str + matchlen + 1,
 707                                             baselen - matchlen - 1,
 708                                             !!S_ISDIR(entry->mode),
 709                                             ps->max_depth) ?
 710                                 entry_interesting : entry_not_interesting;
 711                 }
 712
 713                 /* Either there must be no base, or the base must match. */
 714                 if (baselen == 0 || !basecmp(item, base_str, match, baselen)) {
 715                         if (match_entry(item, entry, pathlen,
 716                                         match + baselen, matchlen - baselen,
 717                                         &never_interesting))
 718                                 return entry_interesting;
 719
 720                         if (item->nowildcard_len < item->len) {
 721                                 if (!git_fnmatch(item, match + baselen, entry->path,
 722                                                  item->nowildcard_len - baselen))
 723                                         return entry_interesting;
 724
 725                                 /*
 726                                  * Match all directories. We'll try to
 727                                  * match files later on.
 728                                  */
 729                                 if (ps->recursive && S_ISDIR(entry->mode))
 730                                         return entry_interesting;
 731                         }
 732
 733                         continue;
 734                 }
 735
 736 match_wildcards:
 737                 if (item->nowildcard_len == item->len)
 738                         continue;
 739
 740                 if (item->nowildcard_len &&
 741                     !match_wildcard_base(item, base_str, baselen, &matched))
 742                         continue;
 743
 744                 /*
 745                  * Concatenate base and entry->path into one and do
 746                  * fnmatch() on it.
 747                  *
 748                  * While we could avoid concatenation in certain cases
 749                  * [1], which saves a memcpy and potentially a
 750                  * realloc, it turns out not worth it. Measurement on
 751                  * linux-2.6 does not show any clear improvements,
 752                  * partly because of the nowildcard_len optimization
 753                  * in git_fnmatch(). Avoid micro-optimizations here.
 754                  *
 755                  * [1] if match_wildcard_base() says the base
 756                  * directory is already matched, we only need to match
 757                  * the rest, which is shorter so _in theory_ faster.
 758                  */
 759
 760                 strbuf_add(base, entry->path, pathlen);
 761
 762                 if (!git_fnmatch(item, match, base->buf + base_offset,
 763                                  item->nowildcard_len)) {
 764                         strbuf_setlen(base, base_offset + baselen);
 765                         return entry_interesting;
 766                 }
 767                 strbuf_setlen(base, base_offset + baselen);
 768
 769                 /*
 770                  * Match all directories. We'll try to match files
 771                  * later on.
 772                  * max_depth is ignored but we may consider support it
 773                  * in future, see
 774                  * http://thread.gmane.org/gmane.comp.version-control.git/163757/focus=163840
 775                  */
 776                 if (ps->recursive && S_ISDIR(entry->mode))
 777                         return entry_interesting;
 778         }
 779         return never_interesting; /* No matches */
 780 }
 781
 782 /*
 783  * Is a tree entry interesting given the pathspec we have?
 784  *
 785  * Pre-condition: either baselen == base_offset (i.e. empty path)
 786  * or base[baselen-1] == '/' (i.e. with trailing slash).
 787  */
 788 enum interesting tree_entry_interesting(const struct name_entry *entry,
 789                                         struct strbuf *base, int base_offset,
 790                                         const struct pathspec *ps)
 791 {
 792         enum interesting positive, negative;
 793         positive = do_match(entry, base, base_offset, ps, 0);
 794
 795         /*
 796          * case | entry | positive | negative | result
 797          * -----+-------+----------+----------+-------
 798          *   1  |  file |   -1     |  -1..2   |  -1
 799          *   2  |  file |    0     |  -1..2   |   0
 800          *   3  |  file |    1     |   -1     |   1
 801          *   4  |  file |    1     |    0     |   1
 802          *   5  |  file |    1     |    1     |   0
 803          *   6  |  file |    1     |    2     |   0
 804          *   7  |  file |    2     |   -1     |   2
 805          *   8  |  file |    2     |    0     |   2
 806          *   9  |  file |    2     |    1     |   0
 807          *  10  |  file |    2     |    2     |  -1
 808          * -----+-------+----------+----------+-------
 809          *  11  |  dir  |   -1     |  -1..2   |  -1
 810          *  12  |  dir  |    0     |  -1..2   |   0
 811          *  13  |  dir  |    1     |   -1     |   1
 812          *  14  |  dir  |    1     |    0     |   1
 813          *  15  |  dir  |    1     |    1     |   1 (*)
 814          *  16  |  dir  |    1     |    2     |   0
 815          *  17  |  dir  |    2     |   -1     |   2
 816          *  18  |  dir  |    2     |    0     |   2
 817          *  19  |  dir  |    2     |    1     |   1 (*)
 818          *  20  |  dir  |    2     |    2     |  -1
 819          *
 820          * (*) An exclude pattern interested in a directory does not
 821          * necessarily mean it will exclude all of the directory. In
 822          * wildcard case, it can't decide until looking at individual
 823          * files inside. So don't write such directories off yet.
 824          */
 825
 826         if (!(ps->magic & PATHSPEC_EXCLUDE) ||
 827             positive <= entry_not_interesting) /* #1, #2, #11, #12 */
 828                 return positive;
 829
 830         negative = do_match(entry, base, base_offset, ps, 1);
 831
 832         /* #3, #4, #7, #8, #13, #14, #17, #18 */
 833         if (negative <= entry_not_interesting)
 834                 return positive;
 835
 836         /* #15, #19 */
 837         if (S_ISDIR(entry->mode) &&
 838             positive >= entry_interesting &&
 839             negative == entry_interesting)
 840                 return entry_interesting;
 841
 842         if ((positive == entry_interesting &&
 843              negative >= entry_interesting) || /* #5, #6, #16 */
 844             (positive == all_entries_interesting &&
 845              negative == entry_interesting)) /* #9 */
 846                 return entry_not_interesting;
 847
 848         return all_entries_not_interesting; /* #10, #20 */
 849 }