git-tag: update usage string and documentation.
[git.git] / diff-index.c
1 #include "cache.h"
2 #include "diff.h"
3
4 static int cached_only = 0;
5 static int match_nonexisting = 0;
6 static struct diff_options diff_options;
7
8 /* A file entry went away or appeared */
9 static void show_file(const char *prefix,
10                       struct cache_entry *ce,
11                       unsigned char *sha1, unsigned int mode)
12 {
13         diff_addremove(&diff_options, prefix[0], ntohl(mode),
14                        sha1, ce->name, NULL);
15 }
16
17 static int get_stat_data(struct cache_entry *ce,
18                          unsigned char **sha1p, unsigned int *modep)
19 {
20         unsigned char *sha1 = ce->sha1;
21         unsigned int mode = ce->ce_mode;
22
23         if (!cached_only) {
24                 static unsigned char no_sha1[20];
25                 int changed;
26                 struct stat st;
27                 if (lstat(ce->name, &st) < 0) {
28                         if (errno == ENOENT && match_nonexisting) {
29                                 *sha1p = sha1;
30                                 *modep = mode;
31                                 return 0;
32                         }
33                         return -1;
34                 }
35                 changed = ce_match_stat(ce, &st);
36                 if (changed) {
37                         mode = create_ce_mode(st.st_mode);
38                         sha1 = no_sha1;
39                 }
40         }
41
42         *sha1p = sha1;
43         *modep = mode;
44         return 0;
45 }
46
47 static void show_new_file(struct cache_entry *new)
48 {
49         unsigned char *sha1;
50         unsigned int mode;
51
52         /* New file in the index: it might actually be different in the working copy */
53         if (get_stat_data(new, &sha1, &mode) < 0)
54                 return;
55
56         show_file("+", new, sha1, mode);
57 }
58
59 static int show_modified(struct cache_entry *old,
60                          struct cache_entry *new,
61                          int report_missing)
62 {
63         unsigned int mode, oldmode;
64         unsigned char *sha1;
65
66         if (get_stat_data(new, &sha1, &mode) < 0) {
67                 if (report_missing)
68                         show_file("-", old, old->sha1, old->ce_mode);
69                 return -1;
70         }
71
72         oldmode = old->ce_mode;
73         if (mode == oldmode && !memcmp(sha1, old->sha1, 20) &&
74             !diff_options.find_copies_harder)
75                 return 0;
76
77         mode = ntohl(mode);
78         oldmode = ntohl(oldmode);
79
80         diff_change(&diff_options, oldmode, mode,
81                     old->sha1, sha1, old->name, NULL);
82         return 0;
83 }
84
85 static int diff_cache(struct cache_entry **ac, int entries, const char **pathspec)
86 {
87         while (entries) {
88                 struct cache_entry *ce = *ac;
89                 int same = (entries > 1) && ce_same_name(ce, ac[1]);
90
91                 if (!ce_path_match(ce, pathspec))
92                         goto skip_entry;
93
94                 switch (ce_stage(ce)) {
95                 case 0:
96                         /* No stage 1 entry? That means it's a new file */
97                         if (!same) {
98                                 show_new_file(ce);
99                                 break;
100                         }
101                         /* Show difference between old and new */
102                         show_modified(ac[1], ce, 1);
103                         break;
104                 case 1:
105                         /* No stage 3 (merge) entry? That means it's been deleted */
106                         if (!same) {
107                                 show_file("-", ce, ce->sha1, ce->ce_mode);
108                                 break;
109                         }
110                         /* We come here with ce pointing at stage 1
111                          * (original tree) and ac[1] pointing at stage
112                          * 3 (unmerged).  show-modified with
113                          * report-mising set to false does not say the
114                          * file is deleted but reports true if work
115                          * tree does not have it, in which case we
116                          * fall through to report the unmerged state.
117                          * Otherwise, we show the differences between
118                          * the original tree and the work tree.
119                          */
120                         if (!cached_only && !show_modified(ce, ac[1], 0))
121                                 break;
122                         /* fallthru */
123                 case 3:
124                         diff_unmerge(&diff_options, ce->name);
125                         break;
126
127                 default:
128                         die("impossible cache entry stage");
129                 }
130
131 skip_entry:
132                 /*
133                  * Ignore all the different stages for this file,
134                  * we've handled the relevant cases now.
135                  */
136                 do {
137                         ac++;
138                         entries--;
139                 } while (entries && ce_same_name(ce, ac[0]));
140         }
141         return 0;
142 }
143
144 /*
145  * This turns all merge entries into "stage 3". That guarantees that
146  * when we read in the new tree (into "stage 1"), we won't lose sight
147  * of the fact that we had unmerged entries.
148  */
149 static void mark_merge_entries(void)
150 {
151         int i;
152         for (i = 0; i < active_nr; i++) {
153                 struct cache_entry *ce = active_cache[i];
154                 if (!ce_stage(ce))
155                         continue;
156                 ce->ce_flags |= htons(CE_STAGEMASK);
157         }
158 }
159
160 static const char diff_cache_usage[] =
161 "git-diff-index [-m] [--cached] "
162 "[<common diff options>] <tree-ish> [<path>...]"
163 COMMON_DIFF_OPTIONS_HELP;
164
165 int main(int argc, const char **argv)
166 {
167         const char *tree_name = NULL;
168         unsigned char sha1[20];
169         const char *prefix = setup_git_directory();
170         const char **pathspec = NULL;
171         void *tree;
172         unsigned long size;
173         int ret;
174         int allow_options = 1;
175         int i;
176
177         diff_setup(&diff_options);
178         for (i = 1; i < argc; i++) {
179                 const char *arg = argv[i];
180                 int diff_opt_cnt;
181
182                 if (!allow_options || *arg != '-') {
183                         if (tree_name)
184                                 break;
185                         tree_name = arg;
186                         continue;
187                 }
188                         
189                 if (!strcmp(arg, "--")) {
190                         allow_options = 0;
191                         continue;
192                 }
193                 if (!strcmp(arg, "-r")) {
194                         /* We accept the -r flag just to look like git-diff-tree */
195                         continue;
196                 }
197                 diff_opt_cnt = diff_opt_parse(&diff_options, argv + i,
198                                               argc - i);
199                 if (diff_opt_cnt < 0)
200                         usage(diff_cache_usage);
201                 else if (diff_opt_cnt) {
202                         i += diff_opt_cnt - 1;
203                         continue;
204                 }
205
206                 if (!strcmp(arg, "-m")) {
207                         match_nonexisting = 1;
208                         continue;
209                 }
210                 if (!strcmp(arg, "--cached")) {
211                         cached_only = 1;
212                         continue;
213                 }
214                 usage(diff_cache_usage);
215         }
216
217         pathspec = get_pathspec(prefix, argv + i);
218
219         if (diff_setup_done(&diff_options) < 0)
220                 usage(diff_cache_usage);
221
222         if (!tree_name || get_sha1(tree_name, sha1))
223                 usage(diff_cache_usage);
224
225         read_cache();
226
227         mark_merge_entries();
228
229         tree = read_object_with_reference(sha1, "tree", &size, NULL);
230         if (!tree)
231                 die("bad tree object %s", tree_name);
232         if (read_tree(tree, size, 1, pathspec))
233                 die("unable to read tree object %s", tree_name);
234
235         ret = diff_cache(active_cache, active_nr, pathspec);
236
237         diffcore_std(&diff_options);
238         diff_flush(&diff_options);
239         return ret;
240 }