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[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                         hashclr(dpath->sha1);
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                                         hashcpy(dpath->parent[stage-2].sha1, nce->sha1);
70                                         dpath->parent[stage-2].mode =
71                                                 canon_mode(mode);
72                                         dpath->parent[stage-2].status =
73                                                 DIFF_STATUS_MODIFIED;
74                                 }
75
76                                 /* diff against the proper unmerged stage */
77                                 if (stage == diff_unmerged_stage)
78                                         ce = nce;
79                                 i++;
80                         }
81                         /*
82                          * Compensate for loop update
83                          */
84                         i--;
85
86                         if (revs->combine_merges && num_compare_stages == 2) {
87                                 show_combined_diff(dpath, 2,
88                                                    revs->dense_combined_merges,
89                                                    revs);
90                                 free(dpath);
91                                 continue;
92                         }
93                         free(dpath);
94                         dpath = NULL;
95
96                         /*
97                          * Show the diff for the 'ce' if we found the one
98                          * from the desired stage.
99                          */
100                         diff_unmerge(&revs->diffopt, ce->name, 0, null_sha1);
101                         if (ce_stage(ce) != diff_unmerged_stage)
102                                 continue;
103                 }
104
105                 if (lstat(ce->name, &st) < 0) {
106                         if (errno != ENOENT && errno != ENOTDIR) {
107                                 perror(ce->name);
108                                 continue;
109                         }
110                         if (silent_on_removed)
111                                 continue;
112                         diff_addremove(&revs->diffopt, '-', ntohl(ce->ce_mode),
113                                        ce->sha1, ce->name, NULL);
114                         continue;
115                 }
116                 changed = ce_match_stat(ce, &st, 0);
117                 if (!changed && !revs->diffopt.find_copies_harder)
118                         continue;
119                 oldmode = ntohl(ce->ce_mode);
120
121                 newmode = canon_mode(st.st_mode);
122                 if (!trust_executable_bit &&
123                     S_ISREG(newmode) && S_ISREG(oldmode) &&
124                     ((newmode ^ oldmode) == 0111))
125                         newmode = oldmode;
126                 diff_change(&revs->diffopt, oldmode, newmode,
127                             ce->sha1, (changed ? null_sha1 : ce->sha1),
128                             ce->name, NULL);
129
130         }
131         diffcore_std(&revs->diffopt);
132         diff_flush(&revs->diffopt);
133         return 0;
134 }
135
136 /*
137  * diff-index
138  */
139
140 /* A file entry went away or appeared */
141 static void diff_index_show_file(struct rev_info *revs,
142                                  const char *prefix,
143                                  struct cache_entry *ce,
144                                  unsigned char *sha1, unsigned int mode)
145 {
146         diff_addremove(&revs->diffopt, prefix[0], ntohl(mode),
147                        sha1, ce->name, NULL);
148 }
149
150 static int get_stat_data(struct cache_entry *ce,
151                          unsigned char **sha1p,
152                          unsigned int *modep,
153                          int cached, int match_missing)
154 {
155         unsigned char *sha1 = ce->sha1;
156         unsigned int mode = ce->ce_mode;
157
158         if (!cached) {
159                 static unsigned char no_sha1[20];
160                 int changed;
161                 struct stat st;
162                 if (lstat(ce->name, &st) < 0) {
163                         if (errno == ENOENT && match_missing) {
164                                 *sha1p = sha1;
165                                 *modep = mode;
166                                 return 0;
167                         }
168                         return -1;
169                 }
170                 changed = ce_match_stat(ce, &st, 0);
171                 if (changed) {
172                         mode = create_ce_mode(st.st_mode);
173                         if (!trust_executable_bit && S_ISREG(st.st_mode))
174                                 mode = ce->ce_mode;
175                         sha1 = no_sha1;
176                 }
177         }
178
179         *sha1p = sha1;
180         *modep = mode;
181         return 0;
182 }
183
184 static void show_new_file(struct rev_info *revs,
185                           struct cache_entry *new,
186                           int cached, int match_missing)
187 {
188         unsigned char *sha1;
189         unsigned int mode;
190
191         /* New file in the index: it might actually be different in
192          * the working copy.
193          */
194         if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0)
195                 return;
196
197         diff_index_show_file(revs, "+", new, sha1, mode);
198 }
199
200 static int show_modified(struct rev_info *revs,
201                          struct cache_entry *old,
202                          struct cache_entry *new,
203                          int report_missing,
204                          int cached, int match_missing)
205 {
206         unsigned int mode, oldmode;
207         unsigned char *sha1;
208
209         if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0) {
210                 if (report_missing)
211                         diff_index_show_file(revs, "-", old,
212                                              old->sha1, old->ce_mode);
213                 return -1;
214         }
215
216         if (revs->combine_merges && !cached &&
217             (hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
218                 struct combine_diff_path *p;
219                 int pathlen = ce_namelen(new);
220
221                 p = xmalloc(combine_diff_path_size(2, pathlen));
222                 p->path = (char *) &p->parent[2];
223                 p->next = NULL;
224                 p->len = pathlen;
225                 memcpy(p->path, new->name, pathlen);
226                 p->path[pathlen] = 0;
227                 p->mode = ntohl(mode);
228                 hashclr(p->sha1);
229                 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
230                 p->parent[0].status = DIFF_STATUS_MODIFIED;
231                 p->parent[0].mode = ntohl(new->ce_mode);
232                 hashcpy(p->parent[0].sha1, new->sha1);
233                 p->parent[1].status = DIFF_STATUS_MODIFIED;
234                 p->parent[1].mode = ntohl(old->ce_mode);
235                 hashcpy(p->parent[1].sha1, old->sha1);
236                 show_combined_diff(p, 2, revs->dense_combined_merges, revs);
237                 free(p);
238                 return 0;
239         }
240
241         oldmode = old->ce_mode;
242         if (mode == oldmode && !hashcmp(sha1, old->sha1) &&
243             !revs->diffopt.find_copies_harder)
244                 return 0;
245
246         mode = ntohl(mode);
247         oldmode = ntohl(oldmode);
248
249         diff_change(&revs->diffopt, oldmode, mode,
250                     old->sha1, sha1, old->name, NULL);
251         return 0;
252 }
253
254 static int diff_cache(struct rev_info *revs,
255                       struct cache_entry **ac, int entries,
256                       const char **pathspec,
257                       int cached, int match_missing)
258 {
259         while (entries) {
260                 struct cache_entry *ce = *ac;
261                 int same = (entries > 1) && ce_same_name(ce, ac[1]);
262
263                 if (!ce_path_match(ce, pathspec))
264                         goto skip_entry;
265
266                 switch (ce_stage(ce)) {
267                 case 0:
268                         /* No stage 1 entry? That means it's a new file */
269                         if (!same) {
270                                 show_new_file(revs, ce, cached, match_missing);
271                                 break;
272                         }
273                         /* Show difference between old and new */
274                         show_modified(revs,ac[1], ce, 1,
275                                       cached, match_missing);
276                         break;
277                 case 1:
278                         /* No stage 3 (merge) entry?
279                          * That means it's been deleted.
280                          */
281                         if (!same) {
282                                 diff_index_show_file(revs, "-", ce,
283                                                      ce->sha1, ce->ce_mode);
284                                 break;
285                         }
286                         /* We come here with ce pointing at stage 1
287                          * (original tree) and ac[1] pointing at stage
288                          * 3 (unmerged).  show-modified with
289                          * report-missing set to false does not say the
290                          * file is deleted but reports true if work
291                          * tree does not have it, in which case we
292                          * fall through to report the unmerged state.
293                          * Otherwise, we show the differences between
294                          * the original tree and the work tree.
295                          */
296                         if (!cached &&
297                             !show_modified(revs, ce, ac[1], 0,
298                                            cached, match_missing))
299                                 break;
300                         diff_unmerge(&revs->diffopt, ce->name,
301                                      ntohl(ce->ce_mode), ce->sha1);
302                         break;
303                 case 3:
304                         diff_unmerge(&revs->diffopt, ce->name,
305                                      0, null_sha1);
306                         break;
307
308                 default:
309                         die("impossible cache entry stage");
310                 }
311
312 skip_entry:
313                 /*
314                  * Ignore all the different stages for this file,
315                  * we've handled the relevant cases now.
316                  */
317                 do {
318                         ac++;
319                         entries--;
320                 } while (entries && ce_same_name(ce, ac[0]));
321         }
322         return 0;
323 }
324
325 /*
326  * This turns all merge entries into "stage 3". That guarantees that
327  * when we read in the new tree (into "stage 1"), we won't lose sight
328  * of the fact that we had unmerged entries.
329  */
330 static void mark_merge_entries(void)
331 {
332         int i;
333         for (i = 0; i < active_nr; i++) {
334                 struct cache_entry *ce = active_cache[i];
335                 if (!ce_stage(ce))
336                         continue;
337                 ce->ce_flags |= htons(CE_STAGEMASK);
338         }
339 }
340
341 int run_diff_index(struct rev_info *revs, int cached)
342 {
343         int ret;
344         struct object *ent;
345         struct tree *tree;
346         const char *tree_name;
347         int match_missing = 0;
348
349         /* 
350          * Backward compatibility wart - "diff-index -m" does
351          * not mean "do not ignore merges", but totally different.
352          */
353         if (!revs->ignore_merges)
354                 match_missing = 1;
355
356         if (read_cache() < 0) {
357                 perror("read_cache");
358                 return -1;
359         }
360         mark_merge_entries();
361
362         ent = revs->pending.objects[0].item;
363         tree_name = revs->pending.objects[0].name;
364         tree = parse_tree_indirect(ent->sha1);
365         if (!tree)
366                 return error("bad tree object %s", tree_name);
367         if (read_tree(tree, 1, revs->prune_data))
368                 return error("unable to read tree object %s", tree_name);
369         ret = diff_cache(revs, active_cache, active_nr, revs->prune_data,
370                          cached, match_missing);
371         diffcore_std(&revs->diffopt);
372         diff_flush(&revs->diffopt);
373         return ret;
374 }