Merge branch 'jc/fsck-dropped-errors'
[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.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 }