git-rm: honor -n flag.
[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
11 /*
12  * diff-files
13  */
14
15 int run_diff_files(struct rev_info *revs, int silent_on_removed)
16 {
17         int entries, i;
18         int diff_unmerged_stage = revs->max_count;
19
20         if (diff_unmerged_stage < 0)
21                 diff_unmerged_stage = 2;
22         entries = read_cache();
23         if (entries < 0) {
24                 perror("read_cache");
25                 return -1;
26         }
27         for (i = 0; i < entries; i++) {
28                 struct stat st;
29                 unsigned int oldmode, newmode;
30                 struct cache_entry *ce = active_cache[i];
31                 int changed;
32
33                 if (!ce_path_match(ce, revs->prune_data))
34                         continue;
35
36                 if (ce_stage(ce)) {
37                         struct {
38                                 struct combine_diff_path p;
39                                 struct combine_diff_parent filler[5];
40                         } combine;
41                         int num_compare_stages = 0;
42
43                         combine.p.next = NULL;
44                         combine.p.len = ce_namelen(ce);
45                         combine.p.path = xmalloc(combine.p.len + 1);
46                         memcpy(combine.p.path, ce->name, combine.p.len);
47                         combine.p.path[combine.p.len] = 0;
48                         combine.p.mode = 0;
49                         memset(combine.p.sha1, 0, 20);
50                         memset(&combine.p.parent[0], 0,
51                                sizeof(combine.filler));
52
53                         while (i < entries) {
54                                 struct cache_entry *nce = active_cache[i];
55                                 int stage;
56
57                                 if (strcmp(ce->name, nce->name))
58                                         break;
59
60                                 /* Stage #2 (ours) is the first parent,
61                                  * stage #3 (theirs) is the second.
62                                  */
63                                 stage = ce_stage(nce);
64                                 if (2 <= stage) {
65                                         int mode = ntohl(nce->ce_mode);
66                                         num_compare_stages++;
67                                         memcpy(combine.p.parent[stage-2].sha1,
68                                                nce->sha1, 20);
69                                         combine.p.parent[stage-2].mode =
70                                                 canon_mode(mode);
71                                         combine.p.parent[stage-2].status =
72                                                 DIFF_STATUS_MODIFIED;
73                                 }
74
75                                 /* diff against the proper unmerged stage */
76                                 if (stage == diff_unmerged_stage)
77                                         ce = nce;
78                                 i++;
79                         }
80                         /*
81                          * Compensate for loop update
82                          */
83                         i--;
84
85                         if (revs->combine_merges && num_compare_stages == 2) {
86                                 show_combined_diff(&combine.p, 2,
87                                                    revs->dense_combined_merges,
88                                                    revs);
89                                 free(combine.p.path);
90                                 continue;
91                         }
92                         free(combine.p.path);
93
94                         /*
95                          * Show the diff for the 'ce' if we found the one
96                          * from the desired stage.
97                          */
98                         diff_unmerge(&revs->diffopt, ce->name);
99                         if (ce_stage(ce) != diff_unmerged_stage)
100                                 continue;
101                 }
102
103                 if (lstat(ce->name, &st) < 0) {
104                         if (errno != ENOENT && errno != ENOTDIR) {
105                                 perror(ce->name);
106                                 continue;
107                         }
108                         if (silent_on_removed)
109                                 continue;
110                         diff_addremove(&revs->diffopt, '-', ntohl(ce->ce_mode),
111                                        ce->sha1, ce->name, NULL);
112                         continue;
113                 }
114                 changed = ce_match_stat(ce, &st, 0);
115                 if (!changed && !revs->diffopt.find_copies_harder)
116                         continue;
117                 oldmode = ntohl(ce->ce_mode);
118
119                 newmode = canon_mode(st.st_mode);
120                 if (!trust_executable_bit &&
121                     S_ISREG(newmode) && S_ISREG(oldmode) &&
122                     ((newmode ^ oldmode) == 0111))
123                         newmode = oldmode;
124                 diff_change(&revs->diffopt, oldmode, newmode,
125                             ce->sha1, (changed ? null_sha1 : ce->sha1),
126                             ce->name, NULL);
127
128         }
129         diffcore_std(&revs->diffopt);
130         diff_flush(&revs->diffopt);
131         return 0;
132 }
133
134 /*
135  * diff-index
136  */
137
138 /* A file entry went away or appeared */
139 static void diff_index_show_file(struct rev_info *revs,
140                                  const char *prefix,
141                                  struct cache_entry *ce,
142                                  unsigned char *sha1, unsigned int mode)
143 {
144         diff_addremove(&revs->diffopt, prefix[0], ntohl(mode),
145                        sha1, ce->name, NULL);
146 }
147
148 static int get_stat_data(struct cache_entry *ce,
149                          unsigned char **sha1p,
150                          unsigned int *modep,
151                          int cached, int match_missing)
152 {
153         unsigned char *sha1 = ce->sha1;
154         unsigned int mode = ce->ce_mode;
155
156         if (!cached) {
157                 static unsigned char no_sha1[20];
158                 int changed;
159                 struct stat st;
160                 if (lstat(ce->name, &st) < 0) {
161                         if (errno == ENOENT && match_missing) {
162                                 *sha1p = sha1;
163                                 *modep = mode;
164                                 return 0;
165                         }
166                         return -1;
167                 }
168                 changed = ce_match_stat(ce, &st, 0);
169                 if (changed) {
170                         mode = create_ce_mode(st.st_mode);
171                         if (!trust_executable_bit && S_ISREG(st.st_mode))
172                                 mode = ce->ce_mode;
173                         sha1 = no_sha1;
174                 }
175         }
176
177         *sha1p = sha1;
178         *modep = mode;
179         return 0;
180 }
181
182 static void show_new_file(struct rev_info *revs,
183                           struct cache_entry *new,
184                           int cached, int match_missing)
185 {
186         unsigned char *sha1;
187         unsigned int mode;
188
189         /* New file in the index: it might actually be different in
190          * the working copy.
191          */
192         if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0)
193                 return;
194
195         diff_index_show_file(revs, "+", new, sha1, mode);
196 }
197
198 static int show_modified(struct rev_info *revs,
199                          struct cache_entry *old,
200                          struct cache_entry *new,
201                          int report_missing,
202                          int cached, int match_missing)
203 {
204         unsigned int mode, oldmode;
205         unsigned char *sha1;
206
207         if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0) {
208                 if (report_missing)
209                         diff_index_show_file(revs, "-", old,
210                                              old->sha1, old->ce_mode);
211                 return -1;
212         }
213
214         oldmode = old->ce_mode;
215         if (mode == oldmode && !memcmp(sha1, old->sha1, 20) &&
216             !revs->diffopt.find_copies_harder)
217                 return 0;
218
219         mode = ntohl(mode);
220         oldmode = ntohl(oldmode);
221
222         diff_change(&revs->diffopt, oldmode, mode,
223                     old->sha1, sha1, old->name, NULL);
224         return 0;
225 }
226
227 static int diff_cache(struct rev_info *revs,
228                       struct cache_entry **ac, int entries,
229                       const char **pathspec,
230                       int cached, int match_missing)
231 {
232         while (entries) {
233                 struct cache_entry *ce = *ac;
234                 int same = (entries > 1) && ce_same_name(ce, ac[1]);
235
236                 if (!ce_path_match(ce, pathspec))
237                         goto skip_entry;
238
239                 switch (ce_stage(ce)) {
240                 case 0:
241                         /* No stage 1 entry? That means it's a new file */
242                         if (!same) {
243                                 show_new_file(revs, ce, cached, match_missing);
244                                 break;
245                         }
246                         /* Show difference between old and new */
247                         show_modified(revs,ac[1], ce, 1,
248                                       cached, match_missing);
249                         break;
250                 case 1:
251                         /* No stage 3 (merge) entry?
252                          * That means it's been deleted.
253                          */
254                         if (!same) {
255                                 diff_index_show_file(revs, "-", ce,
256                                                      ce->sha1, ce->ce_mode);
257                                 break;
258                         }
259                         /* We come here with ce pointing at stage 1
260                          * (original tree) and ac[1] pointing at stage
261                          * 3 (unmerged).  show-modified with
262                          * report-missing set to false does not say the
263                          * file is deleted but reports true if work
264                          * tree does not have it, in which case we
265                          * fall through to report the unmerged state.
266                          * Otherwise, we show the differences between
267                          * the original tree and the work tree.
268                          */
269                         if (!cached &&
270                             !show_modified(revs, ce, ac[1], 0,
271                                            cached, match_missing))
272                                 break;
273                         /* fallthru */
274                 case 3:
275                         diff_unmerge(&revs->diffopt, ce->name);
276                         break;
277
278                 default:
279                         die("impossible cache entry stage");
280                 }
281
282 skip_entry:
283                 /*
284                  * Ignore all the different stages for this file,
285                  * we've handled the relevant cases now.
286                  */
287                 do {
288                         ac++;
289                         entries--;
290                 } while (entries && ce_same_name(ce, ac[0]));
291         }
292         return 0;
293 }
294
295 /*
296  * This turns all merge entries into "stage 3". That guarantees that
297  * when we read in the new tree (into "stage 1"), we won't lose sight
298  * of the fact that we had unmerged entries.
299  */
300 static void mark_merge_entries(void)
301 {
302         int i;
303         for (i = 0; i < active_nr; i++) {
304                 struct cache_entry *ce = active_cache[i];
305                 if (!ce_stage(ce))
306                         continue;
307                 ce->ce_flags |= htons(CE_STAGEMASK);
308         }
309 }
310
311 int run_diff_index(struct rev_info *revs, int cached)
312 {
313         int ret;
314         struct object *ent;
315         struct tree *tree;
316         const char *tree_name;
317         int match_missing = 0;
318
319         /* 
320          * Backward compatibility wart - "diff-index -m" does
321          * not mean "do not ignore merges", but totally different.
322          */
323         if (!revs->ignore_merges)
324                 match_missing = 1;
325
326         if (read_cache() < 0) {
327                 perror("read_cache");
328                 return -1;
329         }
330         mark_merge_entries();
331
332         ent = revs->pending_objects->item;
333         tree_name = revs->pending_objects->name;
334         tree = parse_tree_indirect(ent->sha1);
335         if (!tree)
336                 return error("bad tree object %s", tree_name);
337         if (read_tree(tree, 1, revs->prune_data))
338                 return error("unable to read tree object %s", tree_name);
339         ret = diff_cache(revs, active_cache, active_nr, revs->prune_data,
340                          cached, match_missing);
341         diffcore_std(&revs->diffopt);
342         diff_flush(&revs->diffopt);
343         return ret;
344 }