Merge branch 'jk/rebase-config-insn-fmt-docfix' into maint
[git] / 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.oid  = (const struct object_id *)(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.oid->hash + 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.oid = (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         char *traverse_path;
324
325         for (i = 0; i < n; i++)
326                 tx[i].d = t[i];
327
328         if (info->prev) {
329                 strbuf_grow(&base, info->pathlen);
330                 make_traverse_path(base.buf, info->prev, &info->name);
331                 base.buf[info->pathlen-1] = '/';
332                 strbuf_setlen(&base, info->pathlen);
333                 traverse_path = xstrndup(base.buf, info->pathlen);
334         } else {
335                 traverse_path = xstrndup(info->name.path, info->pathlen);
336         }
337         info->traverse_path = traverse_path;
338         for (;;) {
339                 int trees_used;
340                 unsigned long mask, dirmask;
341                 const char *first = NULL;
342                 int first_len = 0;
343                 struct name_entry *e = NULL;
344                 int len;
345
346                 for (i = 0; i < n; i++) {
347                         e = entry + i;
348                         extended_entry_extract(tx + i, e, NULL, 0);
349                 }
350
351                 /*
352                  * A tree may have "t-2" at the current location even
353                  * though it may have "t" that is a subtree behind it,
354                  * and another tree may return "t".  We want to grab
355                  * all "t" from all trees to match in such a case.
356                  */
357                 for (i = 0; i < n; i++) {
358                         e = entry + i;
359                         if (!e->path)
360                                 continue;
361                         len = tree_entry_len(e);
362                         if (!first) {
363                                 first = e->path;
364                                 first_len = len;
365                                 continue;
366                         }
367                         if (name_compare(e->path, len, first, first_len) < 0) {
368                                 first = e->path;
369                                 first_len = len;
370                         }
371                 }
372
373                 if (first) {
374                         for (i = 0; i < n; i++) {
375                                 e = entry + i;
376                                 extended_entry_extract(tx + i, e, first, first_len);
377                                 /* Cull the ones that are not the earliest */
378                                 if (!e->path)
379                                         continue;
380                                 len = tree_entry_len(e);
381                                 if (name_compare(e->path, len, first, first_len))
382                                         entry_clear(e);
383                         }
384                 }
385
386                 /* Now we have in entry[i] the earliest name from the trees */
387                 mask = 0;
388                 dirmask = 0;
389                 for (i = 0; i < n; i++) {
390                         if (!entry[i].path)
391                                 continue;
392                         mask |= 1ul << i;
393                         if (S_ISDIR(entry[i].mode))
394                                 dirmask |= 1ul << i;
395                         e = &entry[i];
396                 }
397                 if (!mask)
398                         break;
399                 interesting = prune_traversal(e, info, &base, interesting);
400                 if (interesting < 0)
401                         break;
402                 if (interesting) {
403                         trees_used = info->fn(n, mask, dirmask, entry, info);
404                         if (trees_used < 0) {
405                                 error = trees_used;
406                                 if (!info->show_all_errors)
407                                         break;
408                         }
409                         mask &= trees_used;
410                 }
411                 for (i = 0; i < n; i++)
412                         if (mask & (1ul << i))
413                                 update_extended_entry(tx + i, entry + i);
414         }
415         free(entry);
416         for (i = 0; i < n; i++)
417                 free_extended_entry(tx + i);
418         free(tx);
419         free(traverse_path);
420         info->traverse_path = NULL;
421         strbuf_release(&base);
422         return error;
423 }
424
425 struct dir_state {
426         void *tree;
427         unsigned long size;
428         unsigned char sha1[20];
429 };
430
431 static int find_tree_entry(struct tree_desc *t, const char *name, unsigned char *result, unsigned *mode)
432 {
433         int namelen = strlen(name);
434         while (t->size) {
435                 const char *entry;
436                 const struct object_id *oid;
437                 int entrylen, cmp;
438
439                 oid = tree_entry_extract(t, &entry, mode);
440                 entrylen = tree_entry_len(&t->entry);
441                 update_tree_entry(t);
442                 if (entrylen > namelen)
443                         continue;
444                 cmp = memcmp(name, entry, entrylen);
445                 if (cmp > 0)
446                         continue;
447                 if (cmp < 0)
448                         break;
449                 if (entrylen == namelen) {
450                         hashcpy(result, oid->hash);
451                         return 0;
452                 }
453                 if (name[entrylen] != '/')
454                         continue;
455                 if (!S_ISDIR(*mode))
456                         break;
457                 if (++entrylen == namelen) {
458                         hashcpy(result, oid->hash);
459                         return 0;
460                 }
461                 return get_tree_entry(oid->hash, name + entrylen, result, mode);
462         }
463         return -1;
464 }
465
466 int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned char *sha1, unsigned *mode)
467 {
468         int retval;
469         void *tree;
470         unsigned long size;
471         unsigned char root[20];
472
473         tree = read_object_with_reference(tree_sha1, tree_type, &size, root);
474         if (!tree)
475                 return -1;
476
477         if (name[0] == '\0') {
478                 hashcpy(sha1, root);
479                 free(tree);
480                 return 0;
481         }
482
483         if (!size) {
484                 retval = -1;
485         } else {
486                 struct tree_desc t;
487                 init_tree_desc(&t, tree, size);
488                 retval = find_tree_entry(&t, name, sha1, mode);
489         }
490         free(tree);
491         return retval;
492 }
493
494 /*
495  * This is Linux's built-in max for the number of symlinks to follow.
496  * That limit, of course, does not affect git, but it's a reasonable
497  * choice.
498  */
499 #define GET_TREE_ENTRY_FOLLOW_SYMLINKS_MAX_LINKS 40
500
501 /**
502  * Find a tree entry by following symlinks in tree_sha (which is
503  * assumed to be the root of the repository).  In the event that a
504  * symlink points outside the repository (e.g. a link to /foo or a
505  * root-level link to ../foo), the portion of the link which is
506  * outside the repository will be returned in result_path, and *mode
507  * will be set to 0.  It is assumed that result_path is uninitialized.
508  * If there are no symlinks, or the end result of the symlink chain
509  * points to an object inside the repository, result will be filled in
510  * with the sha1 of the found object, and *mode will hold the mode of
511  * the object.
512  *
513  * See the code for enum follow_symlink_result for a description of
514  * the return values.
515  */
516 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)
517 {
518         int retval = MISSING_OBJECT;
519         struct dir_state *parents = NULL;
520         size_t parents_alloc = 0;
521         ssize_t parents_nr = 0;
522         unsigned char current_tree_sha1[20];
523         struct strbuf namebuf = STRBUF_INIT;
524         struct tree_desc t;
525         int follows_remaining = GET_TREE_ENTRY_FOLLOW_SYMLINKS_MAX_LINKS;
526         int i;
527
528         init_tree_desc(&t, NULL, 0UL);
529         strbuf_init(result_path, 0);
530         strbuf_addstr(&namebuf, name);
531         hashcpy(current_tree_sha1, tree_sha1);
532
533         while (1) {
534                 int find_result;
535                 char *first_slash;
536                 char *remainder = NULL;
537
538                 if (!t.buffer) {
539                         void *tree;
540                         unsigned char root[20];
541                         unsigned long size;
542                         tree = read_object_with_reference(current_tree_sha1,
543                                                           tree_type, &size,
544                                                           root);
545                         if (!tree)
546                                 goto done;
547
548                         ALLOC_GROW(parents, parents_nr + 1, parents_alloc);
549                         parents[parents_nr].tree = tree;
550                         parents[parents_nr].size = size;
551                         hashcpy(parents[parents_nr].sha1, root);
552                         parents_nr++;
553
554                         if (namebuf.buf[0] == '\0') {
555                                 hashcpy(result, root);
556                                 retval = FOUND;
557                                 goto done;
558                         }
559
560                         if (!size)
561                                 goto done;
562
563                         /* descend */
564                         init_tree_desc(&t, tree, size);
565                 }
566
567                 /* Handle symlinks to e.g. a//b by removing leading slashes */
568                 while (namebuf.buf[0] == '/') {
569                         strbuf_remove(&namebuf, 0, 1);
570                 }
571
572                 /* Split namebuf into a first component and a remainder */
573                 if ((first_slash = strchr(namebuf.buf, '/'))) {
574                         *first_slash = 0;
575                         remainder = first_slash + 1;
576                 }
577
578                 if (!strcmp(namebuf.buf, "..")) {
579                         struct dir_state *parent;
580                         /*
581                          * We could end up with .. in the namebuf if it
582                          * appears in a symlink.
583                          */
584
585                         if (parents_nr == 1) {
586                                 if (remainder)
587                                         *first_slash = '/';
588                                 strbuf_add(result_path, namebuf.buf,
589                                            namebuf.len);
590                                 *mode = 0;
591                                 retval = FOUND;
592                                 goto done;
593                         }
594                         parent = &parents[parents_nr - 1];
595                         free(parent->tree);
596                         parents_nr--;
597                         parent = &parents[parents_nr - 1];
598                         init_tree_desc(&t, parent->tree, parent->size);
599                         strbuf_remove(&namebuf, 0, remainder ? 3 : 2);
600                         continue;
601                 }
602
603                 /* We could end up here via a symlink to dir/.. */
604                 if (namebuf.buf[0] == '\0') {
605                         hashcpy(result, parents[parents_nr - 1].sha1);
606                         retval = FOUND;
607                         goto done;
608                 }
609
610                 /* Look up the first (or only) path component in the tree. */
611                 find_result = find_tree_entry(&t, namebuf.buf,
612                                               current_tree_sha1, mode);
613                 if (find_result) {
614                         goto done;
615                 }
616
617                 if (S_ISDIR(*mode)) {
618                         if (!remainder) {
619                                 hashcpy(result, current_tree_sha1);
620                                 retval = FOUND;
621                                 goto done;
622                         }
623                         /* Descend the tree */
624                         t.buffer = NULL;
625                         strbuf_remove(&namebuf, 0,
626                                       1 + first_slash - namebuf.buf);
627                 } else if (S_ISREG(*mode)) {
628                         if (!remainder) {
629                                 hashcpy(result, current_tree_sha1);
630                                 retval = FOUND;
631                         } else {
632                                 retval = NOT_DIR;
633                         }
634                         goto done;
635                 } else if (S_ISLNK(*mode)) {
636                         /* Follow a symlink */
637                         unsigned long link_len;
638                         size_t len;
639                         char *contents, *contents_start;
640                         struct dir_state *parent;
641                         enum object_type type;
642
643                         if (follows_remaining-- == 0) {
644                                 /* Too many symlinks followed */
645                                 retval = SYMLINK_LOOP;
646                                 goto done;
647                         }
648
649                         /*
650                          * At this point, we have followed at a least
651                          * one symlink, so on error we need to report this.
652                          */
653                         retval = DANGLING_SYMLINK;
654
655                         contents = read_sha1_file(current_tree_sha1, &type,
656                                                   &link_len);
657
658                         if (!contents)
659                                 goto done;
660
661                         if (contents[0] == '/') {
662                                 strbuf_addstr(result_path, contents);
663                                 free(contents);
664                                 *mode = 0;
665                                 retval = FOUND;
666                                 goto done;
667                         }
668
669                         if (remainder)
670                                 len = first_slash - namebuf.buf;
671                         else
672                                 len = namebuf.len;
673
674                         contents_start = contents;
675
676                         parent = &parents[parents_nr - 1];
677                         init_tree_desc(&t, parent->tree, parent->size);
678                         strbuf_splice(&namebuf, 0, len,
679                                       contents_start, link_len);
680                         if (remainder)
681                                 namebuf.buf[link_len] = '/';
682                         free(contents);
683                 }
684         }
685 done:
686         for (i = 0; i < parents_nr; i++)
687                 free(parents[i].tree);
688         free(parents);
689
690         strbuf_release(&namebuf);
691         return retval;
692 }
693
694 static int match_entry(const struct pathspec_item *item,
695                        const struct name_entry *entry, int pathlen,
696                        const char *match, int matchlen,
697                        enum interesting *never_interesting)
698 {
699         int m = -1; /* signals that we haven't called strncmp() */
700
701         if (item->magic & PATHSPEC_ICASE)
702                 /*
703                  * "Never interesting" trick requires exact
704                  * matching. We could do something clever with inexact
705                  * matching, but it's trickier (and not to forget that
706                  * strcasecmp is locale-dependent, at least in
707                  * glibc). Just disable it for now. It can't be worse
708                  * than the wildcard's codepath of '[Tt][Hi][Is][Ss]'
709                  * pattern.
710                  */
711                 *never_interesting = entry_not_interesting;
712         else if (*never_interesting != entry_not_interesting) {
713                 /*
714                  * We have not seen any match that sorts later
715                  * than the current path.
716                  */
717
718                 /*
719                  * Does match sort strictly earlier than path
720                  * with their common parts?
721                  */
722                 m = strncmp(match, entry->path,
723                             (matchlen < pathlen) ? matchlen : pathlen);
724                 if (m < 0)
725                         return 0;
726
727                 /*
728                  * If we come here even once, that means there is at
729                  * least one pathspec that would sort equal to or
730                  * later than the path we are currently looking at.
731                  * In other words, if we have never reached this point
732                  * after iterating all pathspecs, it means all
733                  * pathspecs are either outside of base, or inside the
734                  * base but sorts strictly earlier than the current
735                  * one.  In either case, they will never match the
736                  * subsequent entries.  In such a case, we initialized
737                  * the variable to -1 and that is what will be
738                  * returned, allowing the caller to terminate early.
739                  */
740                 *never_interesting = entry_not_interesting;
741         }
742
743         if (pathlen > matchlen)
744                 return 0;
745
746         if (matchlen > pathlen) {
747                 if (match[pathlen] != '/')
748                         return 0;
749                 if (!S_ISDIR(entry->mode) && !S_ISGITLINK(entry->mode))
750                         return 0;
751         }
752
753         if (m == -1)
754                 /*
755                  * we cheated and did not do strncmp(), so we do
756                  * that here.
757                  */
758                 m = ps_strncmp(item, match, entry->path, pathlen);
759
760         /*
761          * If common part matched earlier then it is a hit,
762          * because we rejected the case where path is not a
763          * leading directory and is shorter than match.
764          */
765         if (!m)
766                 /*
767                  * match_entry does not check if the prefix part is
768                  * matched case-sensitively. If the entry is a
769                  * directory and part of prefix, it'll be rematched
770                  * eventually by basecmp with special treatment for
771                  * the prefix.
772                  */
773                 return 1;
774
775         return 0;
776 }
777
778 /* :(icase)-aware string compare */
779 static int basecmp(const struct pathspec_item *item,
780                    const char *base, const char *match, int len)
781 {
782         if (item->magic & PATHSPEC_ICASE) {
783                 int ret, n = len > item->prefix ? item->prefix : len;
784                 ret = strncmp(base, match, n);
785                 if (ret)
786                         return ret;
787                 base += n;
788                 match += n;
789                 len -= n;
790         }
791         return ps_strncmp(item, base, match, len);
792 }
793
794 static int match_dir_prefix(const struct pathspec_item *item,
795                             const char *base,
796                             const char *match, int matchlen)
797 {
798         if (basecmp(item, base, match, matchlen))
799                 return 0;
800
801         /*
802          * If the base is a subdirectory of a path which
803          * was specified, all of them are interesting.
804          */
805         if (!matchlen ||
806             base[matchlen] == '/' ||
807             match[matchlen - 1] == '/')
808                 return 1;
809
810         /* Just a random prefix match */
811         return 0;
812 }
813
814 /*
815  * Perform matching on the leading non-wildcard part of
816  * pathspec. item->nowildcard_len must be greater than zero. Return
817  * non-zero if base is matched.
818  */
819 static int match_wildcard_base(const struct pathspec_item *item,
820                                const char *base, int baselen,
821                                int *matched)
822 {
823         const char *match = item->match;
824         /* the wildcard part is not considered in this function */
825         int matchlen = item->nowildcard_len;
826
827         if (baselen) {
828                 int dirlen;
829                 /*
830                  * Return early if base is longer than the
831                  * non-wildcard part but it does not match.
832                  */
833                 if (baselen >= matchlen) {
834                         *matched = matchlen;
835                         return !basecmp(item, base, match, matchlen);
836                 }
837
838                 dirlen = matchlen;
839                 while (dirlen && match[dirlen - 1] != '/')
840                         dirlen--;
841
842                 /*
843                  * Return early if base is shorter than the
844                  * non-wildcard part but it does not match. Note that
845                  * base ends with '/' so we are sure it really matches
846                  * directory
847                  */
848                 if (basecmp(item, base, match, baselen))
849                         return 0;
850                 *matched = baselen;
851         } else
852                 *matched = 0;
853         /*
854          * we could have checked entry against the non-wildcard part
855          * that is not in base and does similar never_interesting
856          * optimization as in match_entry. For now just be happy with
857          * base comparison.
858          */
859         return entry_interesting;
860 }
861
862 /*
863  * Is a tree entry interesting given the pathspec we have?
864  *
865  * Pre-condition: either baselen == base_offset (i.e. empty path)
866  * or base[baselen-1] == '/' (i.e. with trailing slash).
867  */
868 static enum interesting do_match(const struct name_entry *entry,
869                                  struct strbuf *base, int base_offset,
870                                  const struct pathspec *ps,
871                                  int exclude)
872 {
873         int i;
874         int pathlen, baselen = base->len - base_offset;
875         enum interesting never_interesting = ps->has_wildcard ?
876                 entry_not_interesting : all_entries_not_interesting;
877
878         GUARD_PATHSPEC(ps,
879                        PATHSPEC_FROMTOP |
880                        PATHSPEC_MAXDEPTH |
881                        PATHSPEC_LITERAL |
882                        PATHSPEC_GLOB |
883                        PATHSPEC_ICASE |
884                        PATHSPEC_EXCLUDE);
885
886         if (!ps->nr) {
887                 if (!ps->recursive ||
888                     !(ps->magic & PATHSPEC_MAXDEPTH) ||
889                     ps->max_depth == -1)
890                         return all_entries_interesting;
891                 return within_depth(base->buf + base_offset, baselen,
892                                     !!S_ISDIR(entry->mode),
893                                     ps->max_depth) ?
894                         entry_interesting : entry_not_interesting;
895         }
896
897         pathlen = tree_entry_len(entry);
898
899         for (i = ps->nr - 1; i >= 0; i--) {
900                 const struct pathspec_item *item = ps->items+i;
901                 const char *match = item->match;
902                 const char *base_str = base->buf + base_offset;
903                 int matchlen = item->len, matched = 0;
904
905                 if ((!exclude &&   item->magic & PATHSPEC_EXCLUDE) ||
906                     ( exclude && !(item->magic & PATHSPEC_EXCLUDE)))
907                         continue;
908
909                 if (baselen >= matchlen) {
910                         /* If it doesn't match, move along... */
911                         if (!match_dir_prefix(item, base_str, match, matchlen))
912                                 goto match_wildcards;
913
914                         if (!ps->recursive ||
915                             !(ps->magic & PATHSPEC_MAXDEPTH) ||
916                             ps->max_depth == -1)
917                                 return all_entries_interesting;
918
919                         return within_depth(base_str + matchlen + 1,
920                                             baselen - matchlen - 1,
921                                             !!S_ISDIR(entry->mode),
922                                             ps->max_depth) ?
923                                 entry_interesting : entry_not_interesting;
924                 }
925
926                 /* Either there must be no base, or the base must match. */
927                 if (baselen == 0 || !basecmp(item, base_str, match, baselen)) {
928                         if (match_entry(item, entry, pathlen,
929                                         match + baselen, matchlen - baselen,
930                                         &never_interesting))
931                                 return entry_interesting;
932
933                         if (item->nowildcard_len < item->len) {
934                                 if (!git_fnmatch(item, match + baselen, entry->path,
935                                                  item->nowildcard_len - baselen))
936                                         return entry_interesting;
937
938                                 /*
939                                  * Match all directories. We'll try to
940                                  * match files later on.
941                                  */
942                                 if (ps->recursive && S_ISDIR(entry->mode))
943                                         return entry_interesting;
944                         }
945
946                         continue;
947                 }
948
949 match_wildcards:
950                 if (item->nowildcard_len == item->len)
951                         continue;
952
953                 if (item->nowildcard_len &&
954                     !match_wildcard_base(item, base_str, baselen, &matched))
955                         continue;
956
957                 /*
958                  * Concatenate base and entry->path into one and do
959                  * fnmatch() on it.
960                  *
961                  * While we could avoid concatenation in certain cases
962                  * [1], which saves a memcpy and potentially a
963                  * realloc, it turns out not worth it. Measurement on
964                  * linux-2.6 does not show any clear improvements,
965                  * partly because of the nowildcard_len optimization
966                  * in git_fnmatch(). Avoid micro-optimizations here.
967                  *
968                  * [1] if match_wildcard_base() says the base
969                  * directory is already matched, we only need to match
970                  * the rest, which is shorter so _in theory_ faster.
971                  */
972
973                 strbuf_add(base, entry->path, pathlen);
974
975                 if (!git_fnmatch(item, match, base->buf + base_offset,
976                                  item->nowildcard_len)) {
977                         strbuf_setlen(base, base_offset + baselen);
978                         return entry_interesting;
979                 }
980                 strbuf_setlen(base, base_offset + baselen);
981
982                 /*
983                  * Match all directories. We'll try to match files
984                  * later on.
985                  * max_depth is ignored but we may consider support it
986                  * in future, see
987                  * http://thread.gmane.org/gmane.comp.version-control.git/163757/focus=163840
988                  */
989                 if (ps->recursive && S_ISDIR(entry->mode))
990                         return entry_interesting;
991         }
992         return never_interesting; /* No matches */
993 }
994
995 /*
996  * Is a tree entry interesting given the pathspec we have?
997  *
998  * Pre-condition: either baselen == base_offset (i.e. empty path)
999  * or base[baselen-1] == '/' (i.e. with trailing slash).
1000  */
1001 enum interesting tree_entry_interesting(const struct name_entry *entry,
1002                                         struct strbuf *base, int base_offset,
1003                                         const struct pathspec *ps)
1004 {
1005         enum interesting positive, negative;
1006         positive = do_match(entry, base, base_offset, ps, 0);
1007
1008         /*
1009          * case | entry | positive | negative | result
1010          * -----+-------+----------+----------+-------
1011          *   1  |  file |   -1     |  -1..2   |  -1
1012          *   2  |  file |    0     |  -1..2   |   0
1013          *   3  |  file |    1     |   -1     |   1
1014          *   4  |  file |    1     |    0     |   1
1015          *   5  |  file |    1     |    1     |   0
1016          *   6  |  file |    1     |    2     |   0
1017          *   7  |  file |    2     |   -1     |   2
1018          *   8  |  file |    2     |    0     |   2
1019          *   9  |  file |    2     |    1     |   0
1020          *  10  |  file |    2     |    2     |  -1
1021          * -----+-------+----------+----------+-------
1022          *  11  |  dir  |   -1     |  -1..2   |  -1
1023          *  12  |  dir  |    0     |  -1..2   |   0
1024          *  13  |  dir  |    1     |   -1     |   1
1025          *  14  |  dir  |    1     |    0     |   1
1026          *  15  |  dir  |    1     |    1     |   1 (*)
1027          *  16  |  dir  |    1     |    2     |   0
1028          *  17  |  dir  |    2     |   -1     |   2
1029          *  18  |  dir  |    2     |    0     |   2
1030          *  19  |  dir  |    2     |    1     |   1 (*)
1031          *  20  |  dir  |    2     |    2     |  -1
1032          *
1033          * (*) An exclude pattern interested in a directory does not
1034          * necessarily mean it will exclude all of the directory. In
1035          * wildcard case, it can't decide until looking at individual
1036          * files inside. So don't write such directories off yet.
1037          */
1038
1039         if (!(ps->magic & PATHSPEC_EXCLUDE) ||
1040             positive <= entry_not_interesting) /* #1, #2, #11, #12 */
1041                 return positive;
1042
1043         negative = do_match(entry, base, base_offset, ps, 1);
1044
1045         /* #3, #4, #7, #8, #13, #14, #17, #18 */
1046         if (negative <= entry_not_interesting)
1047                 return positive;
1048
1049         /* #15, #19 */
1050         if (S_ISDIR(entry->mode) &&
1051             positive >= entry_interesting &&
1052             negative == entry_interesting)
1053                 return entry_interesting;
1054
1055         if ((positive == entry_interesting &&
1056              negative >= entry_interesting) || /* #5, #6, #16 */
1057             (positive == all_entries_interesting &&
1058              negative == entry_interesting)) /* #9 */
1059                 return entry_not_interesting;
1060
1061         return all_entries_not_interesting; /* #10, #20 */
1062 }