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[git.git] / diff-lib.c
1 /*
2  * Copyright (C) 2005 Junio C Hamano
3  */
4 #include "cache.h"
5 #include "quote.h"
6 #include "commit.h"
7 #include "diff.h"
8 #include "diffcore.h"
9 #include "revision.h"
10 #include "cache-tree.h"
11 #include "unpack-trees.h"
12 #include "refs.h"
14 /*
15  * diff-files
16  */
18 /*
19  * Has the work tree entity been removed?
20  *
21  * Return 1 if it was removed from the work tree, 0 if an entity to be
22  * compared with the cache entry ce still exists (the latter includes
23  * the case where a directory that is not a submodule repository
24  * exists for ce that is a submodule -- it is a submodule that is not
25  * checked out).  Return negative for an error.
26  */
27 static int check_removed(const struct cache_entry *ce, struct stat *st)
28 {
29         if (lstat(ce->name, st) < 0) {
30                 if (errno != ENOENT && errno != ENOTDIR)
31                         return -1;
32                 return 1;
33         }
34         if (has_symlink_leading_path(ce_namelen(ce), ce->name))
35                 return 1;
36         if (S_ISDIR(st->st_mode)) {
37                 unsigned char sub[20];
39                 /*
40                  * If ce is already a gitlink, we can have a plain
41                  * directory (i.e. the submodule is not checked out),
42                  * or a checked out submodule.  Either case this is not
43                  * a case where something was removed from the work tree,
44                  * so we will return 0.
45                  *
46                  * Otherwise, if the directory is not a submodule
47                  * repository, that means ce which was a blob turned into
48                  * a directory --- the blob was removed!
49                  */
50                 if (!S_ISGITLINK(ce->ce_mode) &&
51                     resolve_gitlink_ref(ce->name, "HEAD", sub))
52                         return 1;
53         }
54         return 0;
55 }
57 int run_diff_files(struct rev_info *revs, unsigned int option)
58 {
59         int entries, i;
60         int diff_unmerged_stage = revs->max_count;
61         int silent_on_removed = option & DIFF_SILENT_ON_REMOVED;
62         unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
63                               ? CE_MATCH_RACY_IS_DIRTY : 0);
64         char symcache[PATH_MAX];
66         if (diff_unmerged_stage < 0)
67                 diff_unmerged_stage = 2;
68         entries = active_nr;
69         symcache[0] = '\0';
70         for (i = 0; i < entries; i++) {
71                 struct stat st;
72                 unsigned int oldmode, newmode;
73                 struct cache_entry *ce = active_cache[i];
74                 int changed;
76                 if (DIFF_OPT_TST(&revs->diffopt, QUIET) &&
77                         DIFF_OPT_TST(&revs->diffopt, HAS_CHANGES))
78                         break;
80                 if (!ce_path_match(ce, revs->prune_data))
81                         continue;
83                 if (ce_stage(ce)) {
84                         struct combine_diff_path *dpath;
85                         int num_compare_stages = 0;
86                         size_t path_len;
88                         path_len = ce_namelen(ce);
90                         dpath = xmalloc(combine_diff_path_size(5, path_len));
91                         dpath->path = (char *) &(dpath->parent[5]);
93                         dpath->next = NULL;
94                         dpath->len = path_len;
95                         memcpy(dpath->path, ce->name, path_len);
96                         dpath->path[path_len] = '\0';
97                         hashclr(dpath->sha1);
98                         memset(&(dpath->parent[0]), 0,
99                                sizeof(struct combine_diff_parent)*5);
101                         changed = check_removed(ce, &st);
102                         if (!changed)
103                                 dpath->mode = ce_mode_from_stat(ce, st.st_mode);
104                         else {
105                                 if (changed < 0) {
106                                         perror(ce->name);
107                                         continue;
108                                 }
109                                 if (silent_on_removed)
110                                         continue;
111                         }
113                         while (i < entries) {
114                                 struct cache_entry *nce = active_cache[i];
115                                 int stage;
117                                 if (strcmp(ce->name, nce->name))
118                                         break;
120                                 /* Stage #2 (ours) is the first parent,
121                                  * stage #3 (theirs) is the second.
122                                  */
123                                 stage = ce_stage(nce);
124                                 if (2 <= stage) {
125                                         int mode = nce->ce_mode;
126                                         num_compare_stages++;
127                                         hashcpy(dpath->parent[stage-2].sha1, nce->sha1);
128                                         dpath->parent[stage-2].mode = ce_mode_from_stat(nce, mode);
129                                         dpath->parent[stage-2].status =
130                                                 DIFF_STATUS_MODIFIED;
131                                 }
133                                 /* diff against the proper unmerged stage */
134                                 if (stage == diff_unmerged_stage)
135                                         ce = nce;
136                                 i++;
137                         }
138                         /*
139                          * Compensate for loop update
140                          */
141                         i--;
143                         if (revs->combine_merges && num_compare_stages == 2) {
144                                 show_combined_diff(dpath, 2,
145                                                    revs->dense_combined_merges,
146                                                    revs);
147                                 free(dpath);
148                                 continue;
149                         }
150                         free(dpath);
151                         dpath = NULL;
153                         /*
154                          * Show the diff for the 'ce' if we found the one
155                          * from the desired stage.
156                          */
157                         diff_unmerge(&revs->diffopt, ce->name, 0, null_sha1);
158                         if (ce_stage(ce) != diff_unmerged_stage)
159                                 continue;
160                 }
162                 if (ce_uptodate(ce))
163                         continue;
165                 changed = check_removed(ce, &st);
166                 if (changed) {
167                         if (changed < 0) {
168                                 perror(ce->name);
169                                 continue;
170                         }
171                         if (silent_on_removed)
172                                 continue;
173                         diff_addremove(&revs->diffopt, '-', ce->ce_mode,
174                                        ce->sha1, ce->name, NULL);
175                         continue;
176                 }
177                 changed = ce_match_stat(ce, &st, ce_option);
178                 if (!changed) {
179                         ce_mark_uptodate(ce);
180                         if (!DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
181                                 continue;
182                 }
183                 oldmode = ce->ce_mode;
184                 newmode = ce_mode_from_stat(ce, st.st_mode);
185                 diff_change(&revs->diffopt, oldmode, newmode,
186                             ce->sha1, (changed ? null_sha1 : ce->sha1),
187                             ce->name, NULL);
189         }
190         diffcore_std(&revs->diffopt);
191         diff_flush(&revs->diffopt);
192         return 0;
195 /*
196  * diff-index
197  */
199 struct oneway_unpack_data {
200         struct rev_info *revs;
201         char symcache[PATH_MAX];
202 };
204 /* A file entry went away or appeared */
205 static void diff_index_show_file(struct rev_info *revs,
206                                  const char *prefix,
207                                  struct cache_entry *ce,
208                                  const unsigned char *sha1, unsigned int mode)
210         diff_addremove(&revs->diffopt, prefix[0], mode,
211                        sha1, ce->name, NULL);
214 static int get_stat_data(struct cache_entry *ce,
215                          const unsigned char **sha1p,
216                          unsigned int *modep,
217                          int cached, int match_missing,
218                          struct oneway_unpack_data *cbdata)
220         const unsigned char *sha1 = ce->sha1;
221         unsigned int mode = ce->ce_mode;
223         if (!cached) {
224                 int changed;
225                 struct stat st;
226                 changed = check_removed(ce, &st);
227                 if (changed < 0)
228                         return -1;
229                 else if (changed) {
230                         if (match_missing) {
231                                 *sha1p = sha1;
232                                 *modep = mode;
233                                 return 0;
234                         }
235                         return -1;
236                 }
237                 changed = ce_match_stat(ce, &st, 0);
238                 if (changed) {
239                         mode = ce_mode_from_stat(ce, st.st_mode);
240                         sha1 = null_sha1;
241                 }
242         }
244         *sha1p = sha1;
245         *modep = mode;
246         return 0;
249 static void show_new_file(struct oneway_unpack_data *cbdata,
250                           struct cache_entry *new,
251                           int cached, int match_missing)
253         const unsigned char *sha1;
254         unsigned int mode;
255         struct rev_info *revs = cbdata->revs;
257         /*
258          * New file in the index: it might actually be different in
259          * the working copy.
260          */
261         if (get_stat_data(new, &sha1, &mode, cached, match_missing, cbdata) < 0)
262                 return;
264         diff_index_show_file(revs, "+", new, sha1, mode);
267 static int show_modified(struct oneway_unpack_data *cbdata,
268                          struct cache_entry *old,
269                          struct cache_entry *new,
270                          int report_missing,
271                          int cached, int match_missing)
273         unsigned int mode, oldmode;
274         const unsigned char *sha1;
275         struct rev_info *revs = cbdata->revs;
277         if (get_stat_data(new, &sha1, &mode, cached, match_missing, cbdata) < 0) {
278                 if (report_missing)
279                         diff_index_show_file(revs, "-", old,
280                                              old->sha1, old->ce_mode);
281                 return -1;
282         }
284         if (revs->combine_merges && !cached &&
285             (hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
286                 struct combine_diff_path *p;
287                 int pathlen = ce_namelen(new);
289                 p = xmalloc(combine_diff_path_size(2, pathlen));
290                 p->path = (char *) &p->parent[2];
291                 p->next = NULL;
292                 p->len = pathlen;
293                 memcpy(p->path, new->name, pathlen);
294                 p->path[pathlen] = 0;
295                 p->mode = mode;
296                 hashclr(p->sha1);
297                 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
298                 p->parent[0].status = DIFF_STATUS_MODIFIED;
299                 p->parent[0].mode = new->ce_mode;
300                 hashcpy(p->parent[0].sha1, new->sha1);
301                 p->parent[1].status = DIFF_STATUS_MODIFIED;
302                 p->parent[1].mode = old->ce_mode;
303                 hashcpy(p->parent[1].sha1, old->sha1);
304                 show_combined_diff(p, 2, revs->dense_combined_merges, revs);
305                 free(p);
306                 return 0;
307         }
309         oldmode = old->ce_mode;
310         if (mode == oldmode && !hashcmp(sha1, old->sha1) &&
311             !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
312                 return 0;
314         diff_change(&revs->diffopt, oldmode, mode,
315                     old->sha1, sha1, old->name, NULL);
316         return 0;
319 /*
320  * This turns all merge entries into "stage 3". That guarantees that
321  * when we read in the new tree (into "stage 1"), we won't lose sight
322  * of the fact that we had unmerged entries.
323  */
324 static void mark_merge_entries(void)
326         int i;
327         for (i = 0; i < active_nr; i++) {
328                 struct cache_entry *ce = active_cache[i];
329                 if (!ce_stage(ce))
330                         continue;
331                 ce->ce_flags |= CE_STAGEMASK;
332         }
335 /*
336  * This gets a mix of an existing index and a tree, one pathname entry
337  * at a time. The index entry may be a single stage-0 one, but it could
338  * also be multiple unmerged entries (in which case idx_pos/idx_nr will
339  * give you the position and number of entries in the index).
340  */
341 static void do_oneway_diff(struct unpack_trees_options *o,
342         struct cache_entry *idx,
343         struct cache_entry *tree)
345         struct oneway_unpack_data *cbdata = o->unpack_data;
346         struct rev_info *revs = cbdata->revs;
347         int match_missing, cached;
349         /*
350          * Backward compatibility wart - "diff-index -m" does
351          * not mean "do not ignore merges", but "match_missing".
352          *
353          * But with the revision flag parsing, that's found in
354          * "!revs->ignore_merges".
355          */
356         cached = o->index_only;
357         match_missing = !revs->ignore_merges;
359         if (cached && idx && ce_stage(idx)) {
360                 if (tree)
361                         diff_unmerge(&revs->diffopt, idx->name, idx->ce_mode, idx->sha1);
362                 return;
363         }
365         /*
366          * Something added to the tree?
367          */
368         if (!tree) {
369                 show_new_file(cbdata, idx, cached, match_missing);
370                 return;
371         }
373         /*
374          * Something removed from the tree?
375          */
376         if (!idx) {
377                 diff_index_show_file(revs, "-", tree, tree->sha1, tree->ce_mode);
378                 return;
379         }
381         /* Show difference between old and new */
382         show_modified(cbdata, tree, idx, 1, cached, match_missing);
385 static inline void skip_same_name(struct cache_entry *ce, struct unpack_trees_options *o)
387         int len = ce_namelen(ce);
388         const struct index_state *index = o->src_index;
390         while (o->pos < index->cache_nr) {
391                 struct cache_entry *next = index->cache[o->pos];
392                 if (len != ce_namelen(next))
393                         break;
394                 if (memcmp(ce->name, next->name, len))
395                         break;
396                 o->pos++;
397         }
400 /*
401  * The unpack_trees() interface is designed for merging, so
402  * the different source entries are designed primarily for
403  * the source trees, with the old index being really mainly
404  * used for being replaced by the result.
405  *
406  * For diffing, the index is more important, and we only have a
407  * single tree.
408  *
409  * We're supposed to return how many index entries we want to skip.
410  *
411  * This wrapper makes it all more readable, and takes care of all
412  * the fairly complex unpack_trees() semantic requirements, including
413  * the skipping, the path matching, the type conflict cases etc.
414  */
415 static int oneway_diff(struct cache_entry **src, struct unpack_trees_options *o)
417         struct cache_entry *idx = src[0];
418         struct cache_entry *tree = src[1];
419         struct oneway_unpack_data *cbdata = o->unpack_data;
420         struct rev_info *revs = cbdata->revs;
422         if (idx && ce_stage(idx))
423                 skip_same_name(idx, o);
425         /*
426          * Unpack-trees generates a DF/conflict entry if
427          * there was a directory in the index and a tree
428          * in the tree. From a diff standpoint, that's a
429          * delete of the tree and a create of the file.
430          */
431         if (tree == o->df_conflict_entry)
432                 tree = NULL;
434         if (ce_path_match(idx ? idx : tree, revs->prune_data))
435                 do_oneway_diff(o, idx, tree);
437         return 0;
440 int run_diff_index(struct rev_info *revs, int cached)
442         struct object *ent;
443         struct tree *tree;
444         const char *tree_name;
445         struct unpack_trees_options opts;
446         struct tree_desc t;
447         struct oneway_unpack_data unpack_cb;
449         mark_merge_entries();
451         ent = revs->pending.objects[0].item;
452         tree_name = revs->pending.objects[0].name;
453         tree = parse_tree_indirect(ent->sha1);
454         if (!tree)
455                 return error("bad tree object %s", tree_name);
457         unpack_cb.revs = revs;
458         unpack_cb.symcache[0] = '\0';
459         memset(&opts, 0, sizeof(opts));
460         opts.head_idx = 1;
461         opts.index_only = cached;
462         opts.merge = 1;
463         opts.fn = oneway_diff;
464         opts.unpack_data = &unpack_cb;
465         opts.src_index = &the_index;
466         opts.dst_index = NULL;
468         init_tree_desc(&t, tree->buffer, tree->size);
469         if (unpack_trees(1, &t, &opts))
470                 exit(128);
472         diffcore_std(&revs->diffopt);
473         diff_flush(&revs->diffopt);
474         return 0;
477 int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
479         struct tree *tree;
480         struct rev_info revs;
481         int i;
482         struct cache_entry **dst;
483         struct cache_entry *last = NULL;
484         struct unpack_trees_options opts;
485         struct tree_desc t;
486         struct oneway_unpack_data unpack_cb;
488         /*
489          * This is used by git-blame to run diff-cache internally;
490          * it potentially needs to repeatedly run this, so we will
491          * start by removing the higher order entries the last round
492          * left behind.
493          */
494         dst = active_cache;
495         for (i = 0; i < active_nr; i++) {
496                 struct cache_entry *ce = active_cache[i];
497                 if (ce_stage(ce)) {
498                         if (last && !strcmp(ce->name, last->name))
499                                 continue;
500                         cache_tree_invalidate_path(active_cache_tree,
501                                                    ce->name);
502                         last = ce;
503                         ce->ce_flags |= CE_REMOVE;
504                 }
505                 *dst++ = ce;
506         }
507         active_nr = dst - active_cache;
509         init_revisions(&revs, NULL);
510         revs.prune_data = opt->paths;
511         tree = parse_tree_indirect(tree_sha1);
512         if (!tree)
513                 die("bad tree object %s", sha1_to_hex(tree_sha1));
515         unpack_cb.revs = &revs;
516         unpack_cb.symcache[0] = '\0';
517         memset(&opts, 0, sizeof(opts));
518         opts.head_idx = 1;
519         opts.index_only = 1;
520         opts.merge = 1;
521         opts.fn = oneway_diff;
522         opts.unpack_data = &unpack_cb;
523         opts.src_index = &the_index;
524         opts.dst_index = &the_index;
526         init_tree_desc(&t, tree->buffer, tree->size);
527         if (unpack_trees(1, &t, &opts))
528                 exit(128);
529         return 0;