Minor documentation fixup.
[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 combine_diff_path *dpath;
38                         int num_compare_stages = 0;
39                         size_t path_len;
40
41                         path_len = ce_namelen(ce);
42
43                         dpath = xmalloc (combine_diff_path_size (5, path_len));
44                         dpath->path = (char *) &(dpath->parent[5]);
45
46                         dpath->next = NULL;
47                         dpath->len = path_len;
48                         memcpy(dpath->path, ce->name, path_len);
49                         dpath->path[path_len] = '\0';
50                         dpath->mode = 0;
51                         memset(dpath->sha1, 0, 20);
52                         memset(&(dpath->parent[0]), 0,
53                                         sizeof(struct combine_diff_parent)*5);
54
55                         while (i < entries) {
56                                 struct cache_entry *nce = active_cache[i];
57                                 int stage;
58
59                                 if (strcmp(ce->name, nce->name))
60                                         break;
61
62                                 /* Stage #2 (ours) is the first parent,
63                                  * stage #3 (theirs) is the second.
64                                  */
65                                 stage = ce_stage(nce);
66                                 if (2 <= stage) {
67                                         int mode = ntohl(nce->ce_mode);
68                                         num_compare_stages++;
69                                         memcpy(dpath->parent[stage-2].sha1,
70                                                nce->sha1, 20);
71                                         dpath->parent[stage-2].mode =
72                                                 canon_mode(mode);
73                                         dpath->parent[stage-2].status =
74                                                 DIFF_STATUS_MODIFIED;
75                                 }
76
77                                 /* diff against the proper unmerged stage */
78                                 if (stage == diff_unmerged_stage)
79                                         ce = nce;
80                                 i++;
81                         }
82                         /*
83                          * Compensate for loop update
84                          */
85                         i--;
86
87                         if (revs->combine_merges && num_compare_stages == 2) {
88                                 show_combined_diff(dpath, 2,
89                                                    revs->dense_combined_merges,
90                                                    revs);
91                                 free(dpath);
92                                 continue;
93                         }
94                         free(dpath);
95                         dpath = NULL;
96
97                         /*
98                          * Show the diff for the 'ce' if we found the one
99                          * from the desired stage.
100                          */
101                         diff_unmerge(&revs->diffopt, ce->name);
102                         if (ce_stage(ce) != diff_unmerged_stage)
103                                 continue;
104                 }
105
106                 if (lstat(ce->name, &st) < 0) {
107                         if (errno != ENOENT && errno != ENOTDIR) {
108                                 perror(ce->name);
109                                 continue;
110                         }
111                         if (silent_on_removed)
112                                 continue;
113                         diff_addremove(&revs->diffopt, '-', ntohl(ce->ce_mode),
114                                        ce->sha1, ce->name, NULL);
115                         continue;
116                 }
117                 changed = ce_match_stat(ce, &st, 0);
118                 if (!changed && !revs->diffopt.find_copies_harder)
119                         continue;
120                 oldmode = ntohl(ce->ce_mode);
121
122                 newmode = canon_mode(st.st_mode);
123                 if (!trust_executable_bit &&
124                     S_ISREG(newmode) && S_ISREG(oldmode) &&
125                     ((newmode ^ oldmode) == 0111))
126                         newmode = oldmode;
127                 diff_change(&revs->diffopt, oldmode, newmode,
128                             ce->sha1, (changed ? null_sha1 : ce->sha1),
129                             ce->name, NULL);
130
131         }
132         diffcore_std(&revs->diffopt);
133         diff_flush(&revs->diffopt);
134         return 0;
135 }
136
137 /*
138  * diff-index
139  */
140
141 /* A file entry went away or appeared */
142 static void diff_index_show_file(struct rev_info *revs,
143                                  const char *prefix,
144                                  struct cache_entry *ce,
145                                  unsigned char *sha1, unsigned int mode)
146 {
147         diff_addremove(&revs->diffopt, prefix[0], ntohl(mode),
148                        sha1, ce->name, NULL);
149 }
150
151 static int get_stat_data(struct cache_entry *ce,
152                          unsigned char **sha1p,
153                          unsigned int *modep,
154                          int cached, int match_missing)
155 {
156         unsigned char *sha1 = ce->sha1;
157         unsigned int mode = ce->ce_mode;
158
159         if (!cached) {
160                 static unsigned char no_sha1[20];
161                 int changed;
162                 struct stat st;
163                 if (lstat(ce->name, &st) < 0) {
164                         if (errno == ENOENT && match_missing) {
165                                 *sha1p = sha1;
166                                 *modep = mode;
167                                 return 0;
168                         }
169                         return -1;
170                 }
171                 changed = ce_match_stat(ce, &st, 0);
172                 if (changed) {
173                         mode = create_ce_mode(st.st_mode);
174                         if (!trust_executable_bit && S_ISREG(st.st_mode))
175                                 mode = ce->ce_mode;
176                         sha1 = no_sha1;
177                 }
178         }
179
180         *sha1p = sha1;
181         *modep = mode;
182         return 0;
183 }
184
185 static void show_new_file(struct rev_info *revs,
186                           struct cache_entry *new,
187                           int cached, int match_missing)
188 {
189         unsigned char *sha1;
190         unsigned int mode;
191
192         /* New file in the index: it might actually be different in
193          * the working copy.
194          */
195         if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0)
196                 return;
197
198         diff_index_show_file(revs, "+", new, sha1, mode);
199 }
200
201 static int show_modified(struct rev_info *revs,
202                          struct cache_entry *old,
203                          struct cache_entry *new,
204                          int report_missing,
205                          int cached, int match_missing)
206 {
207         unsigned int mode, oldmode;
208         unsigned char *sha1;
209
210         if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0) {
211                 if (report_missing)
212                         diff_index_show_file(revs, "-", old,
213                                              old->sha1, old->ce_mode);
214                 return -1;
215         }
216
217         oldmode = old->ce_mode;
218         if (mode == oldmode && !memcmp(sha1, old->sha1, 20) &&
219             !revs->diffopt.find_copies_harder)
220                 return 0;
221
222         mode = ntohl(mode);
223         oldmode = ntohl(oldmode);
224
225         diff_change(&revs->diffopt, oldmode, mode,
226                     old->sha1, sha1, old->name, NULL);
227         return 0;
228 }
229
230 static int diff_cache(struct rev_info *revs,
231                       struct cache_entry **ac, int entries,
232                       const char **pathspec,
233                       int cached, int match_missing)
234 {
235         while (entries) {
236                 struct cache_entry *ce = *ac;
237                 int same = (entries > 1) && ce_same_name(ce, ac[1]);
238
239                 if (!ce_path_match(ce, pathspec))
240                         goto skip_entry;
241
242                 switch (ce_stage(ce)) {
243                 case 0:
244                         /* No stage 1 entry? That means it's a new file */
245                         if (!same) {
246                                 show_new_file(revs, ce, cached, match_missing);
247                                 break;
248                         }
249                         /* Show difference between old and new */
250                         show_modified(revs,ac[1], ce, 1,
251                                       cached, match_missing);
252                         break;
253                 case 1:
254                         /* No stage 3 (merge) entry?
255                          * That means it's been deleted.
256                          */
257                         if (!same) {
258                                 diff_index_show_file(revs, "-", ce,
259                                                      ce->sha1, ce->ce_mode);
260                                 break;
261                         }
262                         /* We come here with ce pointing at stage 1
263                          * (original tree) and ac[1] pointing at stage
264                          * 3 (unmerged).  show-modified with
265                          * report-missing set to false does not say the
266                          * file is deleted but reports true if work
267                          * tree does not have it, in which case we
268                          * fall through to report the unmerged state.
269                          * Otherwise, we show the differences between
270                          * the original tree and the work tree.
271                          */
272                         if (!cached &&
273                             !show_modified(revs, ce, ac[1], 0,
274                                            cached, match_missing))
275                                 break;
276                         /* fallthru */
277                 case 3:
278                         diff_unmerge(&revs->diffopt, ce->name);
279                         break;
280
281                 default:
282                         die("impossible cache entry stage");
283                 }
284
285 skip_entry:
286                 /*
287                  * Ignore all the different stages for this file,
288                  * we've handled the relevant cases now.
289                  */
290                 do {
291                         ac++;
292                         entries--;
293                 } while (entries && ce_same_name(ce, ac[0]));
294         }
295         return 0;
296 }
297
298 /*
299  * This turns all merge entries into "stage 3". That guarantees that
300  * when we read in the new tree (into "stage 1"), we won't lose sight
301  * of the fact that we had unmerged entries.
302  */
303 static void mark_merge_entries(void)
304 {
305         int i;
306         for (i = 0; i < active_nr; i++) {
307                 struct cache_entry *ce = active_cache[i];
308                 if (!ce_stage(ce))
309                         continue;
310                 ce->ce_flags |= htons(CE_STAGEMASK);
311         }
312 }
313
314 int run_diff_index(struct rev_info *revs, int cached)
315 {
316         int ret;
317         struct object *ent;
318         struct tree *tree;
319         const char *tree_name;
320         int match_missing = 0;
321
322         /* 
323          * Backward compatibility wart - "diff-index -m" does
324          * not mean "do not ignore merges", but totally different.
325          */
326         if (!revs->ignore_merges)
327                 match_missing = 1;
328
329         if (read_cache() < 0) {
330                 perror("read_cache");
331                 return -1;
332         }
333         mark_merge_entries();
334
335         ent = revs->pending.objects[0].item;
336         tree_name = revs->pending.objects[0].name;
337         tree = parse_tree_indirect(ent->sha1);
338         if (!tree)
339                 return error("bad tree object %s", tree_name);
340         if (read_tree(tree, 1, revs->prune_data))
341                 return error("unable to read tree object %s", tree_name);
342         ret = diff_cache(revs, active_cache, active_nr, revs->prune_data,
343                          cached, match_missing);
344         diffcore_std(&revs->diffopt);
345         diff_flush(&revs->diffopt);
346         return ret;
347 }