Merge branch 'es/local-atomic-push-failure-with-http'
[git] / tree-walk.c
1 #include "cache.h"
2 #include "tree-walk.h"
3 #include "unpack-trees.h"
4 #include "dir.h"
5 #include "object-store.h"
6 #include "tree.h"
7 #include "pathspec.h"
8
9 static const char *get_mode(const char *str, unsigned int *modep)
10 {
11         unsigned char c;
12         unsigned int mode = 0;
13
14         if (*str == ' ')
15                 return NULL;
16
17         while ((c = *str++) != ' ') {
18                 if (c < '0' || c > '7')
19                         return NULL;
20                 mode = (mode << 3) + (c - '0');
21         }
22         *modep = mode;
23         return str;
24 }
25
26 static int decode_tree_entry(struct tree_desc *desc, const char *buf, unsigned long size, struct strbuf *err)
27 {
28         const char *path;
29         unsigned int mode, len;
30         const unsigned hashsz = the_hash_algo->rawsz;
31
32         if (size < hashsz + 3 || buf[size - (hashsz + 1)]) {
33                 strbuf_addstr(err, _("too-short tree object"));
34                 return -1;
35         }
36
37         path = get_mode(buf, &mode);
38         if (!path) {
39                 strbuf_addstr(err, _("malformed mode in tree entry"));
40                 return -1;
41         }
42         if (!*path) {
43                 strbuf_addstr(err, _("empty filename in tree entry"));
44                 return -1;
45         }
46         len = strlen(path) + 1;
47
48         /* Initialize the descriptor entry */
49         desc->entry.path = path;
50         desc->entry.mode = canon_mode(mode);
51         desc->entry.pathlen = len - 1;
52         hashcpy(desc->entry.oid.hash, (const unsigned char *)path + len);
53
54         return 0;
55 }
56
57 static int init_tree_desc_internal(struct tree_desc *desc, const void *buffer, unsigned long size, struct strbuf *err)
58 {
59         desc->buffer = buffer;
60         desc->size = size;
61         if (size)
62                 return decode_tree_entry(desc, buffer, size, err);
63         return 0;
64 }
65
66 void init_tree_desc(struct tree_desc *desc, const void *buffer, unsigned long size)
67 {
68         struct strbuf err = STRBUF_INIT;
69         if (init_tree_desc_internal(desc, buffer, size, &err))
70                 die("%s", err.buf);
71         strbuf_release(&err);
72 }
73
74 int init_tree_desc_gently(struct tree_desc *desc, const void *buffer, unsigned long size)
75 {
76         struct strbuf err = STRBUF_INIT;
77         int result = init_tree_desc_internal(desc, buffer, size, &err);
78         if (result)
79                 error("%s", err.buf);
80         strbuf_release(&err);
81         return result;
82 }
83
84 void *fill_tree_descriptor(struct repository *r,
85                            struct tree_desc *desc,
86                            const struct object_id *oid)
87 {
88         unsigned long size = 0;
89         void *buf = NULL;
90
91         if (oid) {
92                 buf = read_object_with_reference(r, oid, tree_type, &size, NULL);
93                 if (!buf)
94                         die("unable to read tree %s", oid_to_hex(oid));
95         }
96         init_tree_desc(desc, buf, size);
97         return buf;
98 }
99
100 static void entry_clear(struct name_entry *a)
101 {
102         memset(a, 0, sizeof(*a));
103 }
104
105 static void entry_extract(struct tree_desc *t, struct name_entry *a)
106 {
107         *a = t->entry;
108 }
109
110 static int update_tree_entry_internal(struct tree_desc *desc, struct strbuf *err)
111 {
112         const void *buf = desc->buffer;
113         const unsigned char *end = (const unsigned char *)desc->entry.path + desc->entry.pathlen + 1 + the_hash_algo->rawsz;
114         unsigned long size = desc->size;
115         unsigned long len = end - (const unsigned char *)buf;
116
117         if (size < len)
118                 die(_("too-short tree file"));
119         buf = end;
120         size -= len;
121         desc->buffer = buf;
122         desc->size = size;
123         if (size)
124                 return decode_tree_entry(desc, buf, size, err);
125         return 0;
126 }
127
128 void update_tree_entry(struct tree_desc *desc)
129 {
130         struct strbuf err = STRBUF_INIT;
131         if (update_tree_entry_internal(desc, &err))
132                 die("%s", err.buf);
133         strbuf_release(&err);
134 }
135
136 int update_tree_entry_gently(struct tree_desc *desc)
137 {
138         struct strbuf err = STRBUF_INIT;
139         if (update_tree_entry_internal(desc, &err)) {
140                 error("%s", err.buf);
141                 strbuf_release(&err);
142                 /* Stop processing this tree after error */
143                 desc->size = 0;
144                 return -1;
145         }
146         strbuf_release(&err);
147         return 0;
148 }
149
150 int tree_entry(struct tree_desc *desc, struct name_entry *entry)
151 {
152         if (!desc->size)
153                 return 0;
154
155         *entry = desc->entry;
156         update_tree_entry(desc);
157         return 1;
158 }
159
160 int tree_entry_gently(struct tree_desc *desc, struct name_entry *entry)
161 {
162         if (!desc->size)
163                 return 0;
164
165         *entry = desc->entry;
166         if (update_tree_entry_gently(desc))
167                 return 0;
168         return 1;
169 }
170
171 void setup_traverse_info(struct traverse_info *info, const char *base)
172 {
173         int pathlen = strlen(base);
174         static struct traverse_info dummy;
175
176         memset(info, 0, sizeof(*info));
177         if (pathlen && base[pathlen-1] == '/')
178                 pathlen--;
179         info->pathlen = pathlen ? pathlen + 1 : 0;
180         info->name.path = base;
181         info->name.pathlen = pathlen;
182         if (pathlen) {
183                 hashcpy(info->name.oid.hash, (const unsigned char *)base + pathlen + 1);
184                 info->prev = &dummy;
185         }
186 }
187
188 char *make_traverse_path(char *path, const struct traverse_info *info, const struct name_entry *n)
189 {
190         int len = tree_entry_len(n);
191         int pathlen = info->pathlen;
192
193         path[pathlen + len] = 0;
194         for (;;) {
195                 memcpy(path + pathlen, n->path, len);
196                 if (!pathlen)
197                         break;
198                 path[--pathlen] = '/';
199                 n = &info->name;
200                 len = tree_entry_len(n);
201                 info = info->prev;
202                 pathlen -= len;
203         }
204         return path;
205 }
206
207 struct tree_desc_skip {
208         struct tree_desc_skip *prev;
209         const void *ptr;
210 };
211
212 struct tree_desc_x {
213         struct tree_desc d;
214         struct tree_desc_skip *skip;
215 };
216
217 static int check_entry_match(const char *a, int a_len, const char *b, int b_len)
218 {
219         /*
220          * The caller wants to pick *a* from a tree or nothing.
221          * We are looking at *b* in a tree.
222          *
223          * (0) If a and b are the same name, we are trivially happy.
224          *
225          * There are three possibilities where *a* could be hiding
226          * behind *b*.
227          *
228          * (1) *a* == "t",   *b* == "ab"  i.e. *b* sorts earlier than *a* no
229          *                                matter what.
230          * (2) *a* == "t",   *b* == "t-2" and "t" is a subtree in the tree;
231          * (3) *a* == "t-2", *b* == "t"   and "t-2" is a blob in the tree.
232          *
233          * Otherwise we know *a* won't appear in the tree without
234          * scanning further.
235          */
236
237         int cmp = name_compare(a, a_len, b, b_len);
238
239         /* Most common case first -- reading sync'd trees */
240         if (!cmp)
241                 return cmp;
242
243         if (0 < cmp) {
244                 /* a comes after b; it does not matter if it is case (3)
245                 if (b_len < a_len && !memcmp(a, b, b_len) && a[b_len] < '/')
246                         return 1;
247                 */
248                 return 1; /* keep looking */
249         }
250
251         /* b comes after a; are we looking at case (2)? */
252         if (a_len < b_len && !memcmp(a, b, a_len) && b[a_len] < '/')
253                 return 1; /* keep looking */
254
255         return -1; /* a cannot appear in the tree */
256 }
257
258 /*
259  * From the extended tree_desc, extract the first name entry, while
260  * paying attention to the candidate "first" name.  Most importantly,
261  * when looking for an entry, if there are entries that sorts earlier
262  * in the tree object representation than that name, skip them and
263  * process the named entry first.  We will remember that we haven't
264  * processed the first entry yet, and in the later call skip the
265  * entry we processed early when update_extended_entry() is called.
266  *
267  * E.g. if the underlying tree object has these entries:
268  *
269  *    blob    "t-1"
270  *    blob    "t-2"
271  *    tree    "t"
272  *    blob    "t=1"
273  *
274  * and the "first" asks for "t", remember that we still need to
275  * process "t-1" and "t-2" but extract "t".  After processing the
276  * entry "t" from this call, the caller will let us know by calling
277  * update_extended_entry() that we can remember "t" has been processed
278  * already.
279  */
280
281 static void extended_entry_extract(struct tree_desc_x *t,
282                                    struct name_entry *a,
283                                    const char *first,
284                                    int first_len)
285 {
286         const char *path;
287         int len;
288         struct tree_desc probe;
289         struct tree_desc_skip *skip;
290
291         /*
292          * Extract the first entry from the tree_desc, but skip the
293          * ones that we already returned in earlier rounds.
294          */
295         while (1) {
296                 if (!t->d.size) {
297                         entry_clear(a);
298                         break; /* not found */
299                 }
300                 entry_extract(&t->d, a);
301                 for (skip = t->skip; skip; skip = skip->prev)
302                         if (a->path == skip->ptr)
303                                 break; /* found */
304                 if (!skip)
305                         break;
306                 /* We have processed this entry already. */
307                 update_tree_entry(&t->d);
308         }
309
310         if (!first || !a->path)
311                 return;
312
313         /*
314          * The caller wants "first" from this tree, or nothing.
315          */
316         path = a->path;
317         len = tree_entry_len(a);
318         switch (check_entry_match(first, first_len, path, len)) {
319         case -1:
320                 entry_clear(a);
321         case 0:
322                 return;
323         default:
324                 break;
325         }
326
327         /*
328          * We need to look-ahead -- we suspect that a subtree whose
329          * name is "first" may be hiding behind the current entry "path".
330          */
331         probe = t->d;
332         while (probe.size) {
333                 entry_extract(&probe, a);
334                 path = a->path;
335                 len = tree_entry_len(a);
336                 switch (check_entry_match(first, first_len, path, len)) {
337                 case -1:
338                         entry_clear(a);
339                 case 0:
340                         return;
341                 default:
342                         update_tree_entry(&probe);
343                         break;
344                 }
345                 /* keep looking */
346         }
347         entry_clear(a);
348 }
349
350 static void update_extended_entry(struct tree_desc_x *t, struct name_entry *a)
351 {
352         if (t->d.entry.path == a->path) {
353                 update_tree_entry(&t->d);
354         } else {
355                 /* we have returned this entry early */
356                 struct tree_desc_skip *skip = xmalloc(sizeof(*skip));
357                 skip->ptr = a->path;
358                 skip->prev = t->skip;
359                 t->skip = skip;
360         }
361 }
362
363 static void free_extended_entry(struct tree_desc_x *t)
364 {
365         struct tree_desc_skip *p, *s;
366
367         for (s = t->skip; s; s = p) {
368                 p = s->prev;
369                 free(s);
370         }
371 }
372
373 static inline int prune_traversal(struct index_state *istate,
374                                   struct name_entry *e,
375                                   struct traverse_info *info,
376                                   struct strbuf *base,
377                                   int still_interesting)
378 {
379         if (!info->pathspec || still_interesting == 2)
380                 return 2;
381         if (still_interesting < 0)
382                 return still_interesting;
383         return tree_entry_interesting(istate, e, base,
384                                       0, info->pathspec);
385 }
386
387 int traverse_trees(struct index_state *istate,
388                    int n, struct tree_desc *t,
389                    struct traverse_info *info)
390 {
391         int error = 0;
392         struct name_entry *entry = xmalloc(n*sizeof(*entry));
393         int i;
394         struct tree_desc_x *tx = xcalloc(n, sizeof(*tx));
395         struct strbuf base = STRBUF_INIT;
396         int interesting = 1;
397         char *traverse_path;
398
399         for (i = 0; i < n; i++)
400                 tx[i].d = t[i];
401
402         if (info->prev) {
403                 strbuf_grow(&base, info->pathlen);
404                 make_traverse_path(base.buf, info->prev, &info->name);
405                 base.buf[info->pathlen-1] = '/';
406                 strbuf_setlen(&base, info->pathlen);
407                 traverse_path = xstrndup(base.buf, info->pathlen);
408         } else {
409                 traverse_path = xstrndup(info->name.path, info->pathlen);
410         }
411         info->traverse_path = traverse_path;
412         for (;;) {
413                 int trees_used;
414                 unsigned long mask, dirmask;
415                 const char *first = NULL;
416                 int first_len = 0;
417                 struct name_entry *e = NULL;
418                 int len;
419
420                 for (i = 0; i < n; i++) {
421                         e = entry + i;
422                         extended_entry_extract(tx + i, e, NULL, 0);
423                 }
424
425                 /*
426                  * A tree may have "t-2" at the current location even
427                  * though it may have "t" that is a subtree behind it,
428                  * and another tree may return "t".  We want to grab
429                  * all "t" from all trees to match in such a case.
430                  */
431                 for (i = 0; i < n; i++) {
432                         e = entry + i;
433                         if (!e->path)
434                                 continue;
435                         len = tree_entry_len(e);
436                         if (!first) {
437                                 first = e->path;
438                                 first_len = len;
439                                 continue;
440                         }
441                         if (name_compare(e->path, len, first, first_len) < 0) {
442                                 first = e->path;
443                                 first_len = len;
444                         }
445                 }
446
447                 if (first) {
448                         for (i = 0; i < n; i++) {
449                                 e = entry + i;
450                                 extended_entry_extract(tx + i, e, first, first_len);
451                                 /* Cull the ones that are not the earliest */
452                                 if (!e->path)
453                                         continue;
454                                 len = tree_entry_len(e);
455                                 if (name_compare(e->path, len, first, first_len))
456                                         entry_clear(e);
457                         }
458                 }
459
460                 /* Now we have in entry[i] the earliest name from the trees */
461                 mask = 0;
462                 dirmask = 0;
463                 for (i = 0; i < n; i++) {
464                         if (!entry[i].path)
465                                 continue;
466                         mask |= 1ul << i;
467                         if (S_ISDIR(entry[i].mode))
468                                 dirmask |= 1ul << i;
469                         e = &entry[i];
470                 }
471                 if (!mask)
472                         break;
473                 interesting = prune_traversal(istate, e, info, &base, interesting);
474                 if (interesting < 0)
475                         break;
476                 if (interesting) {
477                         trees_used = info->fn(n, mask, dirmask, entry, info);
478                         if (trees_used < 0) {
479                                 error = trees_used;
480                                 if (!info->show_all_errors)
481                                         break;
482                         }
483                         mask &= trees_used;
484                 }
485                 for (i = 0; i < n; i++)
486                         if (mask & (1ul << i))
487                                 update_extended_entry(tx + i, entry + i);
488         }
489         free(entry);
490         for (i = 0; i < n; i++)
491                 free_extended_entry(tx + i);
492         free(tx);
493         free(traverse_path);
494         info->traverse_path = NULL;
495         strbuf_release(&base);
496         return error;
497 }
498
499 struct dir_state {
500         void *tree;
501         unsigned long size;
502         struct object_id oid;
503 };
504
505 static int find_tree_entry(struct repository *r, struct tree_desc *t,
506                            const char *name, struct object_id *result,
507                            unsigned short *mode)
508 {
509         int namelen = strlen(name);
510         while (t->size) {
511                 const char *entry;
512                 struct object_id oid;
513                 int entrylen, cmp;
514
515                 oidcpy(&oid, tree_entry_extract(t, &entry, mode));
516                 entrylen = tree_entry_len(&t->entry);
517                 update_tree_entry(t);
518                 if (entrylen > namelen)
519                         continue;
520                 cmp = memcmp(name, entry, entrylen);
521                 if (cmp > 0)
522                         continue;
523                 if (cmp < 0)
524                         break;
525                 if (entrylen == namelen) {
526                         oidcpy(result, &oid);
527                         return 0;
528                 }
529                 if (name[entrylen] != '/')
530                         continue;
531                 if (!S_ISDIR(*mode))
532                         break;
533                 if (++entrylen == namelen) {
534                         oidcpy(result, &oid);
535                         return 0;
536                 }
537                 return get_tree_entry(r, &oid, name + entrylen, result, mode);
538         }
539         return -1;
540 }
541
542 int get_tree_entry(struct repository *r,
543                    const struct object_id *tree_oid,
544                    const char *name,
545                    struct object_id *oid,
546                    unsigned short *mode)
547 {
548         int retval;
549         void *tree;
550         unsigned long size;
551         struct object_id root;
552
553         tree = read_object_with_reference(r, tree_oid, tree_type, &size, &root);
554         if (!tree)
555                 return -1;
556
557         if (name[0] == '\0') {
558                 oidcpy(oid, &root);
559                 free(tree);
560                 return 0;
561         }
562
563         if (!size) {
564                 retval = -1;
565         } else {
566                 struct tree_desc t;
567                 init_tree_desc(&t, tree, size);
568                 retval = find_tree_entry(r, &t, name, oid, mode);
569         }
570         free(tree);
571         return retval;
572 }
573
574 /*
575  * This is Linux's built-in max for the number of symlinks to follow.
576  * That limit, of course, does not affect git, but it's a reasonable
577  * choice.
578  */
579 #define GET_TREE_ENTRY_FOLLOW_SYMLINKS_MAX_LINKS 40
580
581 /**
582  * Find a tree entry by following symlinks in tree_sha (which is
583  * assumed to be the root of the repository).  In the event that a
584  * symlink points outside the repository (e.g. a link to /foo or a
585  * root-level link to ../foo), the portion of the link which is
586  * outside the repository will be returned in result_path, and *mode
587  * will be set to 0.  It is assumed that result_path is uninitialized.
588  * If there are no symlinks, or the end result of the symlink chain
589  * points to an object inside the repository, result will be filled in
590  * with the sha1 of the found object, and *mode will hold the mode of
591  * the object.
592  *
593  * See the code for enum get_oid_result for a description of
594  * the return values.
595  */
596 enum get_oid_result get_tree_entry_follow_symlinks(struct repository *r,
597                 struct object_id *tree_oid, const char *name,
598                 struct object_id *result, struct strbuf *result_path,
599                 unsigned short *mode)
600 {
601         int retval = MISSING_OBJECT;
602         struct dir_state *parents = NULL;
603         size_t parents_alloc = 0;
604         size_t i, parents_nr = 0;
605         struct object_id current_tree_oid;
606         struct strbuf namebuf = STRBUF_INIT;
607         struct tree_desc t;
608         int follows_remaining = GET_TREE_ENTRY_FOLLOW_SYMLINKS_MAX_LINKS;
609
610         init_tree_desc(&t, NULL, 0UL);
611         strbuf_addstr(&namebuf, name);
612         oidcpy(&current_tree_oid, tree_oid);
613
614         while (1) {
615                 int find_result;
616                 char *first_slash;
617                 char *remainder = NULL;
618
619                 if (!t.buffer) {
620                         void *tree;
621                         struct object_id root;
622                         unsigned long size;
623                         tree = read_object_with_reference(r,
624                                                           &current_tree_oid,
625                                                           tree_type, &size,
626                                                           &root);
627                         if (!tree)
628                                 goto done;
629
630                         ALLOC_GROW(parents, parents_nr + 1, parents_alloc);
631                         parents[parents_nr].tree = tree;
632                         parents[parents_nr].size = size;
633                         oidcpy(&parents[parents_nr].oid, &root);
634                         parents_nr++;
635
636                         if (namebuf.buf[0] == '\0') {
637                                 oidcpy(result, &root);
638                                 retval = FOUND;
639                                 goto done;
640                         }
641
642                         if (!size)
643                                 goto done;
644
645                         /* descend */
646                         init_tree_desc(&t, tree, size);
647                 }
648
649                 /* Handle symlinks to e.g. a//b by removing leading slashes */
650                 while (namebuf.buf[0] == '/') {
651                         strbuf_remove(&namebuf, 0, 1);
652                 }
653
654                 /* Split namebuf into a first component and a remainder */
655                 if ((first_slash = strchr(namebuf.buf, '/'))) {
656                         *first_slash = 0;
657                         remainder = first_slash + 1;
658                 }
659
660                 if (!strcmp(namebuf.buf, "..")) {
661                         struct dir_state *parent;
662                         /*
663                          * We could end up with .. in the namebuf if it
664                          * appears in a symlink.
665                          */
666
667                         if (parents_nr == 1) {
668                                 if (remainder)
669                                         *first_slash = '/';
670                                 strbuf_add(result_path, namebuf.buf,
671                                            namebuf.len);
672                                 *mode = 0;
673                                 retval = FOUND;
674                                 goto done;
675                         }
676                         parent = &parents[parents_nr - 1];
677                         free(parent->tree);
678                         parents_nr--;
679                         parent = &parents[parents_nr - 1];
680                         init_tree_desc(&t, parent->tree, parent->size);
681                         strbuf_remove(&namebuf, 0, remainder ? 3 : 2);
682                         continue;
683                 }
684
685                 /* We could end up here via a symlink to dir/.. */
686                 if (namebuf.buf[0] == '\0') {
687                         oidcpy(result, &parents[parents_nr - 1].oid);
688                         retval = FOUND;
689                         goto done;
690                 }
691
692                 /* Look up the first (or only) path component in the tree. */
693                 find_result = find_tree_entry(r, &t, namebuf.buf,
694                                               &current_tree_oid, mode);
695                 if (find_result) {
696                         goto done;
697                 }
698
699                 if (S_ISDIR(*mode)) {
700                         if (!remainder) {
701                                 oidcpy(result, &current_tree_oid);
702                                 retval = FOUND;
703                                 goto done;
704                         }
705                         /* Descend the tree */
706                         t.buffer = NULL;
707                         strbuf_remove(&namebuf, 0,
708                                       1 + first_slash - namebuf.buf);
709                 } else if (S_ISREG(*mode)) {
710                         if (!remainder) {
711                                 oidcpy(result, &current_tree_oid);
712                                 retval = FOUND;
713                         } else {
714                                 retval = NOT_DIR;
715                         }
716                         goto done;
717                 } else if (S_ISLNK(*mode)) {
718                         /* Follow a symlink */
719                         unsigned long link_len;
720                         size_t len;
721                         char *contents, *contents_start;
722                         struct dir_state *parent;
723                         enum object_type type;
724
725                         if (follows_remaining-- == 0) {
726                                 /* Too many symlinks followed */
727                                 retval = SYMLINK_LOOP;
728                                 goto done;
729                         }
730
731                         /*
732                          * At this point, we have followed at a least
733                          * one symlink, so on error we need to report this.
734                          */
735                         retval = DANGLING_SYMLINK;
736
737                         contents = repo_read_object_file(r,
738                                                     &current_tree_oid, &type,
739                                                     &link_len);
740
741                         if (!contents)
742                                 goto done;
743
744                         if (contents[0] == '/') {
745                                 strbuf_addstr(result_path, contents);
746                                 free(contents);
747                                 *mode = 0;
748                                 retval = FOUND;
749                                 goto done;
750                         }
751
752                         if (remainder)
753                                 len = first_slash - namebuf.buf;
754                         else
755                                 len = namebuf.len;
756
757                         contents_start = contents;
758
759                         parent = &parents[parents_nr - 1];
760                         init_tree_desc(&t, parent->tree, parent->size);
761                         strbuf_splice(&namebuf, 0, len,
762                                       contents_start, link_len);
763                         if (remainder)
764                                 namebuf.buf[link_len] = '/';
765                         free(contents);
766                 }
767         }
768 done:
769         for (i = 0; i < parents_nr; i++)
770                 free(parents[i].tree);
771         free(parents);
772
773         strbuf_release(&namebuf);
774         return retval;
775 }
776
777 static int match_entry(const struct pathspec_item *item,
778                        const struct name_entry *entry, int pathlen,
779                        const char *match, int matchlen,
780                        enum interesting *never_interesting)
781 {
782         int m = -1; /* signals that we haven't called strncmp() */
783
784         if (item->magic & PATHSPEC_ICASE)
785                 /*
786                  * "Never interesting" trick requires exact
787                  * matching. We could do something clever with inexact
788                  * matching, but it's trickier (and not to forget that
789                  * strcasecmp is locale-dependent, at least in
790                  * glibc). Just disable it for now. It can't be worse
791                  * than the wildcard's codepath of '[Tt][Hi][Is][Ss]'
792                  * pattern.
793                  */
794                 *never_interesting = entry_not_interesting;
795         else if (*never_interesting != entry_not_interesting) {
796                 /*
797                  * We have not seen any match that sorts later
798                  * than the current path.
799                  */
800
801                 /*
802                  * Does match sort strictly earlier than path
803                  * with their common parts?
804                  */
805                 m = strncmp(match, entry->path,
806                             (matchlen < pathlen) ? matchlen : pathlen);
807                 if (m < 0)
808                         return 0;
809
810                 /*
811                  * If we come here even once, that means there is at
812                  * least one pathspec that would sort equal to or
813                  * later than the path we are currently looking at.
814                  * In other words, if we have never reached this point
815                  * after iterating all pathspecs, it means all
816                  * pathspecs are either outside of base, or inside the
817                  * base but sorts strictly earlier than the current
818                  * one.  In either case, they will never match the
819                  * subsequent entries.  In such a case, we initialized
820                  * the variable to -1 and that is what will be
821                  * returned, allowing the caller to terminate early.
822                  */
823                 *never_interesting = entry_not_interesting;
824         }
825
826         if (pathlen > matchlen)
827                 return 0;
828
829         if (matchlen > pathlen) {
830                 if (match[pathlen] != '/')
831                         return 0;
832                 if (!S_ISDIR(entry->mode) && !S_ISGITLINK(entry->mode))
833                         return 0;
834         }
835
836         if (m == -1)
837                 /*
838                  * we cheated and did not do strncmp(), so we do
839                  * that here.
840                  */
841                 m = ps_strncmp(item, match, entry->path, pathlen);
842
843         /*
844          * If common part matched earlier then it is a hit,
845          * because we rejected the case where path is not a
846          * leading directory and is shorter than match.
847          */
848         if (!m)
849                 /*
850                  * match_entry does not check if the prefix part is
851                  * matched case-sensitively. If the entry is a
852                  * directory and part of prefix, it'll be rematched
853                  * eventually by basecmp with special treatment for
854                  * the prefix.
855                  */
856                 return 1;
857
858         return 0;
859 }
860
861 /* :(icase)-aware string compare */
862 static int basecmp(const struct pathspec_item *item,
863                    const char *base, const char *match, int len)
864 {
865         if (item->magic & PATHSPEC_ICASE) {
866                 int ret, n = len > item->prefix ? item->prefix : len;
867                 ret = strncmp(base, match, n);
868                 if (ret)
869                         return ret;
870                 base += n;
871                 match += n;
872                 len -= n;
873         }
874         return ps_strncmp(item, base, match, len);
875 }
876
877 static int match_dir_prefix(const struct pathspec_item *item,
878                             const char *base,
879                             const char *match, int matchlen)
880 {
881         if (basecmp(item, base, match, matchlen))
882                 return 0;
883
884         /*
885          * If the base is a subdirectory of a path which
886          * was specified, all of them are interesting.
887          */
888         if (!matchlen ||
889             base[matchlen] == '/' ||
890             match[matchlen - 1] == '/')
891                 return 1;
892
893         /* Just a random prefix match */
894         return 0;
895 }
896
897 /*
898  * Perform matching on the leading non-wildcard part of
899  * pathspec. item->nowildcard_len must be greater than zero. Return
900  * non-zero if base is matched.
901  */
902 static int match_wildcard_base(const struct pathspec_item *item,
903                                const char *base, int baselen,
904                                int *matched)
905 {
906         const char *match = item->match;
907         /* the wildcard part is not considered in this function */
908         int matchlen = item->nowildcard_len;
909
910         if (baselen) {
911                 int dirlen;
912                 /*
913                  * Return early if base is longer than the
914                  * non-wildcard part but it does not match.
915                  */
916                 if (baselen >= matchlen) {
917                         *matched = matchlen;
918                         return !basecmp(item, base, match, matchlen);
919                 }
920
921                 dirlen = matchlen;
922                 while (dirlen && match[dirlen - 1] != '/')
923                         dirlen--;
924
925                 /*
926                  * Return early if base is shorter than the
927                  * non-wildcard part but it does not match. Note that
928                  * base ends with '/' so we are sure it really matches
929                  * directory
930                  */
931                 if (basecmp(item, base, match, baselen))
932                         return 0;
933                 *matched = baselen;
934         } else
935                 *matched = 0;
936         /*
937          * we could have checked entry against the non-wildcard part
938          * that is not in base and does similar never_interesting
939          * optimization as in match_entry. For now just be happy with
940          * base comparison.
941          */
942         return entry_interesting;
943 }
944
945 /*
946  * Is a tree entry interesting given the pathspec we have?
947  *
948  * Pre-condition: either baselen == base_offset (i.e. empty path)
949  * or base[baselen-1] == '/' (i.e. with trailing slash).
950  */
951 static enum interesting do_match(struct index_state *istate,
952                                  const struct name_entry *entry,
953                                  struct strbuf *base, int base_offset,
954                                  const struct pathspec *ps,
955                                  int exclude)
956 {
957         int i;
958         int pathlen, baselen = base->len - base_offset;
959         enum interesting never_interesting = ps->has_wildcard ?
960                 entry_not_interesting : all_entries_not_interesting;
961
962         GUARD_PATHSPEC(ps,
963                        PATHSPEC_FROMTOP |
964                        PATHSPEC_MAXDEPTH |
965                        PATHSPEC_LITERAL |
966                        PATHSPEC_GLOB |
967                        PATHSPEC_ICASE |
968                        PATHSPEC_EXCLUDE |
969                        PATHSPEC_ATTR);
970
971         if (!ps->nr) {
972                 if (!ps->recursive ||
973                     !(ps->magic & PATHSPEC_MAXDEPTH) ||
974                     ps->max_depth == -1)
975                         return all_entries_interesting;
976                 return within_depth(base->buf + base_offset, baselen,
977                                     !!S_ISDIR(entry->mode),
978                                     ps->max_depth) ?
979                         entry_interesting : entry_not_interesting;
980         }
981
982         pathlen = tree_entry_len(entry);
983
984         for (i = ps->nr - 1; i >= 0; i--) {
985                 const struct pathspec_item *item = ps->items+i;
986                 const char *match = item->match;
987                 const char *base_str = base->buf + base_offset;
988                 int matchlen = item->len, matched = 0;
989
990                 if ((!exclude &&   item->magic & PATHSPEC_EXCLUDE) ||
991                     ( exclude && !(item->magic & PATHSPEC_EXCLUDE)))
992                         continue;
993
994                 if (baselen >= matchlen) {
995                         /* If it doesn't match, move along... */
996                         if (!match_dir_prefix(item, base_str, match, matchlen))
997                                 goto match_wildcards;
998
999                         if (!ps->recursive ||
1000                             !(ps->magic & PATHSPEC_MAXDEPTH) ||
1001                             ps->max_depth == -1) {
1002                                 if (!item->attr_match_nr)
1003                                         return all_entries_interesting;
1004                                 else
1005                                         goto interesting;
1006                         }
1007
1008                         if (within_depth(base_str + matchlen + 1,
1009                                          baselen - matchlen - 1,
1010                                          !!S_ISDIR(entry->mode),
1011                                          ps->max_depth))
1012                                 goto interesting;
1013                         else
1014                                 return entry_not_interesting;
1015                 }
1016
1017                 /* Either there must be no base, or the base must match. */
1018                 if (baselen == 0 || !basecmp(item, base_str, match, baselen)) {
1019                         if (match_entry(item, entry, pathlen,
1020                                         match + baselen, matchlen - baselen,
1021                                         &never_interesting))
1022                                 goto interesting;
1023
1024                         if (item->nowildcard_len < item->len) {
1025                                 if (!git_fnmatch(item, match + baselen, entry->path,
1026                                                  item->nowildcard_len - baselen))
1027                                         goto interesting;
1028
1029                                 /*
1030                                  * Match all directories. We'll try to
1031                                  * match files later on.
1032                                  */
1033                                 if (ps->recursive && S_ISDIR(entry->mode))
1034                                         return entry_interesting;
1035
1036                                 /*
1037                                  * When matching against submodules with
1038                                  * wildcard characters, ensure that the entry
1039                                  * at least matches up to the first wild
1040                                  * character.  More accurate matching can then
1041                                  * be performed in the submodule itself.
1042                                  */
1043                                 if (ps->recurse_submodules &&
1044                                     S_ISGITLINK(entry->mode) &&
1045                                     !ps_strncmp(item, match + baselen,
1046                                                 entry->path,
1047                                                 item->nowildcard_len - baselen))
1048                                         goto interesting;
1049                         }
1050
1051                         continue;
1052                 }
1053
1054 match_wildcards:
1055                 if (item->nowildcard_len == item->len)
1056                         continue;
1057
1058                 if (item->nowildcard_len &&
1059                     !match_wildcard_base(item, base_str, baselen, &matched))
1060                         continue;
1061
1062                 /*
1063                  * Concatenate base and entry->path into one and do
1064                  * fnmatch() on it.
1065                  *
1066                  * While we could avoid concatenation in certain cases
1067                  * [1], which saves a memcpy and potentially a
1068                  * realloc, it turns out not worth it. Measurement on
1069                  * linux-2.6 does not show any clear improvements,
1070                  * partly because of the nowildcard_len optimization
1071                  * in git_fnmatch(). Avoid micro-optimizations here.
1072                  *
1073                  * [1] if match_wildcard_base() says the base
1074                  * directory is already matched, we only need to match
1075                  * the rest, which is shorter so _in theory_ faster.
1076                  */
1077
1078                 strbuf_add(base, entry->path, pathlen);
1079
1080                 if (!git_fnmatch(item, match, base->buf + base_offset,
1081                                  item->nowildcard_len)) {
1082                         strbuf_setlen(base, base_offset + baselen);
1083                         goto interesting;
1084                 }
1085
1086                 /*
1087                  * When matching against submodules with
1088                  * wildcard characters, ensure that the entry
1089                  * at least matches up to the first wild
1090                  * character.  More accurate matching can then
1091                  * be performed in the submodule itself.
1092                  */
1093                 if (ps->recurse_submodules && S_ISGITLINK(entry->mode) &&
1094                     !ps_strncmp(item, match, base->buf + base_offset,
1095                                 item->nowildcard_len)) {
1096                         strbuf_setlen(base, base_offset + baselen);
1097                         goto interesting;
1098                 }
1099
1100                 strbuf_setlen(base, base_offset + baselen);
1101
1102                 /*
1103                  * Match all directories. We'll try to match files
1104                  * later on.
1105                  * max_depth is ignored but we may consider support it
1106                  * in future, see
1107                  * https://public-inbox.org/git/7vmxo5l2g4.fsf@alter.siamese.dyndns.org/
1108                  */
1109                 if (ps->recursive && S_ISDIR(entry->mode))
1110                         return entry_interesting;
1111                 continue;
1112 interesting:
1113                 if (item->attr_match_nr) {
1114                         int ret;
1115
1116                         /*
1117                          * Must not return all_entries_not_interesting
1118                          * prematurely. We do not know if all entries do not
1119                          * match some attributes with current attr API.
1120                          */
1121                         never_interesting = entry_not_interesting;
1122
1123                         /*
1124                          * Consider all directories interesting (because some
1125                          * of those files inside may match some attributes
1126                          * even though the parent dir does not)
1127                          *
1128                          * FIXME: attributes _can_ match directories and we
1129                          * can probably return all_entries_interesting or
1130                          * all_entries_not_interesting here if matched.
1131                          */
1132                         if (S_ISDIR(entry->mode))
1133                                 return entry_interesting;
1134
1135                         strbuf_add(base, entry->path, pathlen);
1136                         ret = match_pathspec_attrs(istate, base->buf + base_offset,
1137                                                    base->len - base_offset, item);
1138                         strbuf_setlen(base, base_offset + baselen);
1139                         if (!ret)
1140                                 continue;
1141                 }
1142                 return entry_interesting;
1143         }
1144         return never_interesting; /* No matches */
1145 }
1146
1147 /*
1148  * Is a tree entry interesting given the pathspec we have?
1149  *
1150  * Pre-condition: either baselen == base_offset (i.e. empty path)
1151  * or base[baselen-1] == '/' (i.e. with trailing slash).
1152  */
1153 enum interesting tree_entry_interesting(struct index_state *istate,
1154                                         const struct name_entry *entry,
1155                                         struct strbuf *base, int base_offset,
1156                                         const struct pathspec *ps)
1157 {
1158         enum interesting positive, negative;
1159         positive = do_match(istate, entry, base, base_offset, ps, 0);
1160
1161         /*
1162          * case | entry | positive | negative | result
1163          * -----+-------+----------+----------+-------
1164          *   1  |  file |   -1     |  -1..2   |  -1
1165          *   2  |  file |    0     |  -1..2   |   0
1166          *   3  |  file |    1     |   -1     |   1
1167          *   4  |  file |    1     |    0     |   1
1168          *   5  |  file |    1     |    1     |   0
1169          *   6  |  file |    1     |    2     |   0
1170          *   7  |  file |    2     |   -1     |   2
1171          *   8  |  file |    2     |    0     |   1
1172          *   9  |  file |    2     |    1     |   0
1173          *  10  |  file |    2     |    2     |  -1
1174          * -----+-------+----------+----------+-------
1175          *  11  |  dir  |   -1     |  -1..2   |  -1
1176          *  12  |  dir  |    0     |  -1..2   |   0
1177          *  13  |  dir  |    1     |   -1     |   1
1178          *  14  |  dir  |    1     |    0     |   1
1179          *  15  |  dir  |    1     |    1     |   1 (*)
1180          *  16  |  dir  |    1     |    2     |   0
1181          *  17  |  dir  |    2     |   -1     |   2
1182          *  18  |  dir  |    2     |    0     |   1
1183          *  19  |  dir  |    2     |    1     |   1 (*)
1184          *  20  |  dir  |    2     |    2     |  -1
1185          *
1186          * (*) An exclude pattern interested in a directory does not
1187          * necessarily mean it will exclude all of the directory. In
1188          * wildcard case, it can't decide until looking at individual
1189          * files inside. So don't write such directories off yet.
1190          */
1191
1192         if (!(ps->magic & PATHSPEC_EXCLUDE) ||
1193             positive <= entry_not_interesting) /* #1, #2, #11, #12 */
1194                 return positive;
1195
1196         negative = do_match(istate, entry, base, base_offset, ps, 1);
1197
1198         /* #8, #18 */
1199         if (positive == all_entries_interesting &&
1200             negative == entry_not_interesting)
1201                 return entry_interesting;
1202
1203         /* #3, #4, #7, #13, #14, #17 */
1204         if (negative <= entry_not_interesting)
1205                 return positive;
1206
1207         /* #15, #19 */
1208         if (S_ISDIR(entry->mode) &&
1209             positive >= entry_interesting &&
1210             negative == entry_interesting)
1211                 return entry_interesting;
1212
1213         if ((positive == entry_interesting &&
1214              negative >= entry_interesting) || /* #5, #6, #16 */
1215             (positive == all_entries_interesting &&
1216              negative == entry_interesting)) /* #9 */
1217                 return entry_not_interesting;
1218
1219         return all_entries_not_interesting; /* #10, #20 */
1220 }