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 struct dir_state {
 419         void *tree;
 420         unsigned long size;
 421         unsigned char sha1[20];
 422 };
 423
 424 static int find_tree_entry(struct tree_desc *t, const char *name, unsigned char *result, unsigned *mode)
 425 {
 426         int namelen = strlen(name);
 427         while (t->size) {
 428                 const char *entry;
 429                 const unsigned char *sha1;
 430                 int entrylen, cmp;
 431
 432                 sha1 = tree_entry_extract(t, &entry, mode);
 433                 entrylen = tree_entry_len(&t->entry);
 434                 update_tree_entry(t);
 435                 if (entrylen > namelen)
 436                         continue;
 437                 cmp = memcmp(name, entry, entrylen);
 438                 if (cmp > 0)
 439                         continue;
 440                 if (cmp < 0)
 441                         break;
 442                 if (entrylen == namelen) {
 443                         hashcpy(result, sha1);
 444                         return 0;
 445                 }
 446                 if (name[entrylen] != '/')
 447                         continue;
 448                 if (!S_ISDIR(*mode))
 449                         break;
 450                 if (++entrylen == namelen) {
 451                         hashcpy(result, sha1);
 452                         return 0;
 453                 }
 454                 return get_tree_entry(sha1, name + entrylen, result, mode);
 455         }
 456         return -1;
 457 }
 458
 459 int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned char *sha1, unsigned *mode)
 460 {
 461         int retval;
 462         void *tree;
 463         unsigned long size;
 464         unsigned char root[20];
 465
 466         tree = read_object_with_reference(tree_sha1, tree_type, &size, root);
 467         if (!tree)
 468                 return -1;
 469
 470         if (name[0] == '\0') {
 471                 hashcpy(sha1, root);
 472                 free(tree);
 473                 return 0;
 474         }
 475
 476         if (!size) {
 477                 retval = -1;
 478         } else {
 479                 struct tree_desc t;
 480                 init_tree_desc(&t, tree, size);
 481                 retval = find_tree_entry(&t, name, sha1, mode);
 482         }
 483         free(tree);
 484         return retval;
 485 }
 486
 487 /*
 488  * This is Linux's built-in max for the number of symlinks to follow.
 489  * That limit, of course, does not affect git, but it's a reasonable
 490  * choice.
 491  */
 492 #define GET_TREE_ENTRY_FOLLOW_SYMLINKS_MAX_LINKS 40
 493
 494 /**
 495  * Find a tree entry by following symlinks in tree_sha (which is
 496  * assumed to be the root of the repository).  In the event that a
 497  * symlink points outside the repository (e.g. a link to /foo or a
 498  * root-level link to ../foo), the portion of the link which is
 499  * outside the repository will be returned in result_path, and *mode
 500  * will be set to 0.  It is assumed that result_path is uninitialized.
 501  * If there are no symlinks, or the end result of the symlink chain
 502  * points to an object inside the repository, result will be filled in
 503  * with the sha1 of the found object, and *mode will hold the mode of
 504  * the object.
 505  *
 506  * See the code for enum follow_symlink_result for a description of
 507  * the return values.
 508  */
 509 enum follow_symlinks_result get_tree_entry_follow_symlinks(unsigned char *tree_sha1, const char *name, unsigned char *result, struct strbuf *result_path, unsigned *mode)
 510 {
 511         int retval = MISSING_OBJECT;
 512         struct dir_state *parents = NULL;
 513         size_t parents_alloc = 0;
 514         ssize_t parents_nr = 0;
 515         unsigned char current_tree_sha1[20];
 516         struct strbuf namebuf = STRBUF_INIT;
 517         struct tree_desc t;
 518         int follows_remaining = GET_TREE_ENTRY_FOLLOW_SYMLINKS_MAX_LINKS;
 519         int i;
 520
 521         init_tree_desc(&t, NULL, 0UL);
 522         strbuf_init(result_path, 0);
 523         strbuf_addstr(&namebuf, name);
 524         hashcpy(current_tree_sha1, tree_sha1);
 525
 526         while (1) {
 527                 int find_result;
 528                 char *first_slash;
 529                 char *remainder = NULL;
 530
 531                 if (!t.buffer) {
 532                         void *tree;
 533                         unsigned char root[20];
 534                         unsigned long size;
 535                         tree = read_object_with_reference(current_tree_sha1,
 536                                                           tree_type, &size,
 537                                                           root);
 538                         if (!tree)
 539                                 goto done;
 540
 541                         ALLOC_GROW(parents, parents_nr + 1, parents_alloc);
 542                         parents[parents_nr].tree = tree;
 543                         parents[parents_nr].size = size;
 544                         hashcpy(parents[parents_nr].sha1, root);
 545                         parents_nr++;
 546
 547                         if (namebuf.buf[0] == '\0') {
 548                                 hashcpy(result, root);
 549                                 retval = FOUND;
 550                                 goto done;
 551                         }
 552
 553                         if (!size)
 554                                 goto done;
 555
 556                         /* descend */
 557                         init_tree_desc(&t, tree, size);
 558                 }
 559
 560                 /* Handle symlinks to e.g. a//b by removing leading slashes */
 561                 while (namebuf.buf[0] == '/') {
 562                         strbuf_remove(&namebuf, 0, 1);
 563                 }
 564
 565                 /* Split namebuf into a first component and a remainder */
 566                 if ((first_slash = strchr(namebuf.buf, '/'))) {
 567                         *first_slash = 0;
 568                         remainder = first_slash + 1;
 569                 }
 570
 571                 if (!strcmp(namebuf.buf, "..")) {
 572                         struct dir_state *parent;
 573                         /*
 574                          * We could end up with .. in the namebuf if it
 575                          * appears in a symlink.
 576                          */
 577
 578                         if (parents_nr == 1) {
 579                                 if (remainder)
 580                                         *first_slash = '/';
 581                                 strbuf_add(result_path, namebuf.buf,
 582                                            namebuf.len);
 583                                 *mode = 0;
 584                                 retval = FOUND;
 585                                 goto done;
 586                         }
 587                         parent = &parents[parents_nr - 1];
 588                         free(parent->tree);
 589                         parents_nr--;
 590                         parent = &parents[parents_nr - 1];
 591                         init_tree_desc(&t, parent->tree, parent->size);
 592                         strbuf_remove(&namebuf, 0, remainder ? 3 : 2);
 593                         continue;
 594                 }
 595
 596                 /* We could end up here via a symlink to dir/.. */
 597                 if (namebuf.buf[0] == '\0') {
 598                         hashcpy(result, parents[parents_nr - 1].sha1);
 599                         retval = FOUND;
 600                         goto done;
 601                 }
 602
 603                 /* Look up the first (or only) path component in the tree. */
 604                 find_result = find_tree_entry(&t, namebuf.buf,
 605                                               current_tree_sha1, mode);
 606                 if (find_result) {
 607                         goto done;
 608                 }
 609
 610                 if (S_ISDIR(*mode)) {
 611                         if (!remainder) {
 612                                 hashcpy(result, current_tree_sha1);
 613                                 retval = FOUND;
 614                                 goto done;
 615                         }
 616                         /* Descend the tree */
 617                         t.buffer = NULL;
 618                         strbuf_remove(&namebuf, 0,
 619                                       1 + first_slash - namebuf.buf);
 620                 } else if (S_ISREG(*mode)) {
 621                         if (!remainder) {
 622                                 hashcpy(result, current_tree_sha1);
 623                                 retval = FOUND;
 624                         } else {
 625                                 retval = NOT_DIR;
 626                         }
 627                         goto done;
 628                 } else if (S_ISLNK(*mode)) {
 629                         /* Follow a symlink */
 630                         unsigned long link_len;
 631                         size_t len;
 632                         char *contents, *contents_start;
 633                         struct dir_state *parent;
 634                         enum object_type type;
 635
 636                         if (follows_remaining-- == 0) {
 637                                 /* Too many symlinks followed */
 638                                 retval = SYMLINK_LOOP;
 639                                 goto done;
 640                         }
 641
 642                         /*
 643                          * At this point, we have followed at a least
 644                          * one symlink, so on error we need to report this.
 645                          */
 646                         retval = DANGLING_SYMLINK;
 647
 648                         contents = read_sha1_file(current_tree_sha1, &type,
 649                                                   &link_len);
 650
 651                         if (!contents)
 652                                 goto done;
 653
 654                         if (contents[0] == '/') {
 655                                 strbuf_addstr(result_path, contents);
 656                                 free(contents);
 657                                 *mode = 0;
 658                                 retval = FOUND;
 659                                 goto done;
 660                         }
 661
 662                         if (remainder)
 663                                 len = first_slash - namebuf.buf;
 664                         else
 665                                 len = namebuf.len;
 666
 667                         contents_start = contents;
 668
 669                         parent = &parents[parents_nr - 1];
 670                         init_tree_desc(&t, parent->tree, parent->size);
 671                         strbuf_splice(&namebuf, 0, len,
 672                                       contents_start, link_len);
 673                         if (remainder)
 674                                 namebuf.buf[link_len] = '/';
 675                         free(contents);
 676                 }
 677         }
 678 done:
 679         for (i = 0; i < parents_nr; i++)
 680                 free(parents[i].tree);
 681         free(parents);
 682
 683         strbuf_release(&namebuf);
 684         return retval;
 685 }
 686
 687 static int match_entry(const struct pathspec_item *item,
 688                        const struct name_entry *entry, int pathlen,
 689                        const char *match, int matchlen,
 690                        enum interesting *never_interesting)
 691 {
 692         int m = -1; /* signals that we haven't called strncmp() */
 693
 694         if (item->magic & PATHSPEC_ICASE)
 695                 /*
 696                  * "Never interesting" trick requires exact
 697                  * matching. We could do something clever with inexact
 698                  * matching, but it's trickier (and not to forget that
 699                  * strcasecmp is locale-dependent, at least in
 700                  * glibc). Just disable it for now. It can't be worse
 701                  * than the wildcard's codepath of '[Tt][Hi][Is][Ss]'
 702                  * pattern.
 703                  */
 704                 *never_interesting = entry_not_interesting;
 705         else if (*never_interesting != entry_not_interesting) {
 706                 /*
 707                  * We have not seen any match that sorts later
 708                  * than the current path.
 709                  */
 710
 711                 /*
 712                  * Does match sort strictly earlier than path
 713                  * with their common parts?
 714                  */
 715                 m = strncmp(match, entry->path,
 716                             (matchlen < pathlen) ? matchlen : pathlen);
 717                 if (m < 0)
 718                         return 0;
 719
 720                 /*
 721                  * If we come here even once, that means there is at
 722                  * least one pathspec that would sort equal to or
 723                  * later than the path we are currently looking at.
 724                  * In other words, if we have never reached this point
 725                  * after iterating all pathspecs, it means all
 726                  * pathspecs are either outside of base, or inside the
 727                  * base but sorts strictly earlier than the current
 728                  * one.  In either case, they will never match the
 729                  * subsequent entries.  In such a case, we initialized
 730                  * the variable to -1 and that is what will be
 731                  * returned, allowing the caller to terminate early.
 732                  */
 733                 *never_interesting = entry_not_interesting;
 734         }
 735
 736         if (pathlen > matchlen)
 737                 return 0;
 738
 739         if (matchlen > pathlen) {
 740                 if (match[pathlen] != '/')
 741                         return 0;
 742                 if (!S_ISDIR(entry->mode) && !S_ISGITLINK(entry->mode))
 743                         return 0;
 744         }
 745
 746         if (m == -1)
 747                 /*
 748                  * we cheated and did not do strncmp(), so we do
 749                  * that here.
 750                  */
 751                 m = ps_strncmp(item, match, entry->path, pathlen);
 752
 753         /*
 754          * If common part matched earlier then it is a hit,
 755          * because we rejected the case where path is not a
 756          * leading directory and is shorter than match.
 757          */
 758         if (!m)
 759                 /*
 760                  * match_entry does not check if the prefix part is
 761                  * matched case-sensitively. If the entry is a
 762                  * directory and part of prefix, it'll be rematched
 763                  * eventually by basecmp with special treatment for
 764                  * the prefix.
 765                  */
 766                 return 1;
 767
 768         return 0;
 769 }
 770
 771 /* :(icase)-aware string compare */
 772 static int basecmp(const struct pathspec_item *item,
 773                    const char *base, const char *match, int len)
 774 {
 775         if (item->magic & PATHSPEC_ICASE) {
 776                 int ret, n = len > item->prefix ? item->prefix : len;
 777                 ret = strncmp(base, match, n);
 778                 if (ret)
 779                         return ret;
 780                 base += n;
 781                 match += n;
 782                 len -= n;
 783         }
 784         return ps_strncmp(item, base, match, len);
 785 }
 786
 787 static int match_dir_prefix(const struct pathspec_item *item,
 788                             const char *base,
 789                             const char *match, int matchlen)
 790 {
 791         if (basecmp(item, base, match, matchlen))
 792                 return 0;
 793
 794         /*
 795          * If the base is a subdirectory of a path which
 796          * was specified, all of them are interesting.
 797          */
 798         if (!matchlen ||
 799             base[matchlen] == '/' ||
 800             match[matchlen - 1] == '/')
 801                 return 1;
 802
 803         /* Just a random prefix match */
 804         return 0;
 805 }
 806
 807 /*
 808  * Perform matching on the leading non-wildcard part of
 809  * pathspec. item->nowildcard_len must be greater than zero. Return
 810  * non-zero if base is matched.
 811  */
 812 static int match_wildcard_base(const struct pathspec_item *item,
 813                                const char *base, int baselen,
 814                                int *matched)
 815 {
 816         const char *match = item->match;
 817         /* the wildcard part is not considered in this function */
 818         int matchlen = item->nowildcard_len;
 819
 820         if (baselen) {
 821                 int dirlen;
 822                 /*
 823                  * Return early if base is longer than the
 824                  * non-wildcard part but it does not match.
 825                  */
 826                 if (baselen >= matchlen) {
 827                         *matched = matchlen;
 828                         return !basecmp(item, base, match, matchlen);
 829                 }
 830
 831                 dirlen = matchlen;
 832                 while (dirlen && match[dirlen - 1] != '/')
 833                         dirlen--;
 834
 835                 /*
 836                  * Return early if base is shorter than the
 837                  * non-wildcard part but it does not match. Note that
 838                  * base ends with '/' so we are sure it really matches
 839                  * directory
 840                  */
 841                 if (basecmp(item, base, match, baselen))
 842                         return 0;
 843                 *matched = baselen;
 844         } else
 845                 *matched = 0;
 846         /*
 847          * we could have checked entry against the non-wildcard part
 848          * that is not in base and does similar never_interesting
 849          * optimization as in match_entry. For now just be happy with
 850          * base comparison.
 851          */
 852         return entry_interesting;
 853 }
 854
 855 /*
 856  * Is a tree entry interesting given the pathspec we have?
 857  *
 858  * Pre-condition: either baselen == base_offset (i.e. empty path)
 859  * or base[baselen-1] == '/' (i.e. with trailing slash).
 860  */
 861 static enum interesting do_match(const struct name_entry *entry,
 862                                  struct strbuf *base, int base_offset,
 863                                  const struct pathspec *ps,
 864                                  int exclude)
 865 {
 866         int i;
 867         int pathlen, baselen = base->len - base_offset;
 868         enum interesting never_interesting = ps->has_wildcard ?
 869                 entry_not_interesting : all_entries_not_interesting;
 870
 871         GUARD_PATHSPEC(ps,
 872                        PATHSPEC_FROMTOP |
 873                        PATHSPEC_MAXDEPTH |
 874                        PATHSPEC_LITERAL |
 875                        PATHSPEC_GLOB |
 876                        PATHSPEC_ICASE |
 877                        PATHSPEC_EXCLUDE);
 878
 879         if (!ps->nr) {
 880                 if (!ps->recursive ||
 881                     !(ps->magic & PATHSPEC_MAXDEPTH) ||
 882                     ps->max_depth == -1)
 883                         return all_entries_interesting;
 884                 return within_depth(base->buf + base_offset, baselen,
 885                                     !!S_ISDIR(entry->mode),
 886                                     ps->max_depth) ?
 887                         entry_interesting : entry_not_interesting;
 888         }
 889
 890         pathlen = tree_entry_len(entry);
 891
 892         for (i = ps->nr - 1; i >= 0; i--) {
 893                 const struct pathspec_item *item = ps->items+i;
 894                 const char *match = item->match;
 895                 const char *base_str = base->buf + base_offset;
 896                 int matchlen = item->len, matched = 0;
 897
 898                 if ((!exclude &&   item->magic & PATHSPEC_EXCLUDE) ||
 899                     ( exclude && !(item->magic & PATHSPEC_EXCLUDE)))
 900                         continue;
 901
 902                 if (baselen >= matchlen) {
 903                         /* If it doesn't match, move along... */
 904                         if (!match_dir_prefix(item, base_str, match, matchlen))
 905                                 goto match_wildcards;
 906
 907                         if (!ps->recursive ||
 908                             !(ps->magic & PATHSPEC_MAXDEPTH) ||
 909                             ps->max_depth == -1)
 910                                 return all_entries_interesting;
 911
 912                         return within_depth(base_str + matchlen + 1,
 913                                             baselen - matchlen - 1,
 914                                             !!S_ISDIR(entry->mode),
 915                                             ps->max_depth) ?
 916                                 entry_interesting : entry_not_interesting;
 917                 }
 918
 919                 /* Either there must be no base, or the base must match. */
 920                 if (baselen == 0 || !basecmp(item, base_str, match, baselen)) {
 921                         if (match_entry(item, entry, pathlen,
 922                                         match + baselen, matchlen - baselen,
 923                                         &never_interesting))
 924                                 return entry_interesting;
 925
 926                         if (item->nowildcard_len < item->len) {
 927                                 if (!git_fnmatch(item, match + baselen, entry->path,
 928                                                  item->nowildcard_len - baselen))
 929                                         return entry_interesting;
 930
 931                                 /*
 932                                  * Match all directories. We'll try to
 933                                  * match files later on.
 934                                  */
 935                                 if (ps->recursive && S_ISDIR(entry->mode))
 936                                         return entry_interesting;
 937                         }
 938
 939                         continue;
 940                 }
 941
 942 match_wildcards:
 943                 if (item->nowildcard_len == item->len)
 944                         continue;
 945
 946                 if (item->nowildcard_len &&
 947                     !match_wildcard_base(item, base_str, baselen, &matched))
 948                         continue;
 949
 950                 /*
 951                  * Concatenate base and entry->path into one and do
 952                  * fnmatch() on it.
 953                  *
 954                  * While we could avoid concatenation in certain cases
 955                  * [1], which saves a memcpy and potentially a
 956                  * realloc, it turns out not worth it. Measurement on
 957                  * linux-2.6 does not show any clear improvements,
 958                  * partly because of the nowildcard_len optimization
 959                  * in git_fnmatch(). Avoid micro-optimizations here.
 960                  *
 961                  * [1] if match_wildcard_base() says the base
 962                  * directory is already matched, we only need to match
 963                  * the rest, which is shorter so _in theory_ faster.
 964                  */
 965
 966                 strbuf_add(base, entry->path, pathlen);
 967
 968                 if (!git_fnmatch(item, match, base->buf + base_offset,
 969                                  item->nowildcard_len)) {
 970                         strbuf_setlen(base, base_offset + baselen);
 971                         return entry_interesting;
 972                 }
 973                 strbuf_setlen(base, base_offset + baselen);
 974
 975                 /*
 976                  * Match all directories. We'll try to match files
 977                  * later on.
 978                  * max_depth is ignored but we may consider support it
 979                  * in future, see
 980                  * http://thread.gmane.org/gmane.comp.version-control.git/163757/focus=163840
 981                  */
 982                 if (ps->recursive && S_ISDIR(entry->mode))
 983                         return entry_interesting;
 984         }
 985         return never_interesting; /* No matches */
 986 }
 987
 988 /*
 989  * Is a tree entry interesting given the pathspec we have?
 990  *
 991  * Pre-condition: either baselen == base_offset (i.e. empty path)
 992  * or base[baselen-1] == '/' (i.e. with trailing slash).
 993  */
 994 enum interesting tree_entry_interesting(const struct name_entry *entry,
 995                                         struct strbuf *base, int base_offset,
 996                                         const struct pathspec *ps)
 997 {
 998         enum interesting positive, negative;
 999         positive = do_match(entry, base, base_offset, ps, 0);
1000
1001         /*
1002          * case | entry | positive | negative | result
1003          * -----+-------+----------+----------+-------
1004          *   1  |  file |   -1     |  -1..2   |  -1
1005          *   2  |  file |    0     |  -1..2   |   0
1006          *   3  |  file |    1     |   -1     |   1
1007          *   4  |  file |    1     |    0     |   1
1008          *   5  |  file |    1     |    1     |   0
1009          *   6  |  file |    1     |    2     |   0
1010          *   7  |  file |    2     |   -1     |   2
1011          *   8  |  file |    2     |    0     |   2
1012          *   9  |  file |    2     |    1     |   0
1013          *  10  |  file |    2     |    2     |  -1
1014          * -----+-------+----------+----------+-------
1015          *  11  |  dir  |   -1     |  -1..2   |  -1
1016          *  12  |  dir  |    0     |  -1..2   |   0
1017          *  13  |  dir  |    1     |   -1     |   1
1018          *  14  |  dir  |    1     |    0     |   1
1019          *  15  |  dir  |    1     |    1     |   1 (*)
1020          *  16  |  dir  |    1     |    2     |   0
1021          *  17  |  dir  |    2     |   -1     |   2
1022          *  18  |  dir  |    2     |    0     |   2
1023          *  19  |  dir  |    2     |    1     |   1 (*)
1024          *  20  |  dir  |    2     |    2     |  -1
1025          *
1026          * (*) An exclude pattern interested in a directory does not
1027          * necessarily mean it will exclude all of the directory. In
1028          * wildcard case, it can't decide until looking at individual
1029          * files inside. So don't write such directories off yet.
1030          */
1031
1032         if (!(ps->magic & PATHSPEC_EXCLUDE) ||
1033             positive <= entry_not_interesting) /* #1, #2, #11, #12 */
1034                 return positive;
1035
1036         negative = do_match(entry, base, base_offset, ps, 1);
1037
1038         /* #3, #4, #7, #8, #13, #14, #17, #18 */
1039         if (negative <= entry_not_interesting)
1040                 return positive;
1041
1042         /* #15, #19 */
1043         if (S_ISDIR(entry->mode) &&
1044             positive >= entry_interesting &&
1045             negative == entry_interesting)
1046                 return entry_interesting;
1047
1048         if ((positive == entry_interesting &&
1049              negative >= entry_interesting) || /* #5, #6, #16 */
1050             (positive == all_entries_interesting &&
1051              negative == entry_interesting)) /* #9 */
1052                 return entry_not_interesting;
1053
1054         return all_entries_not_interesting; /* #10, #20 */
1055 }