[PATCH] Update git-diff-cache documentation.
[git] / diff-cache.c
1 #include "cache.h"
2 #include "diff.h"
3
4 static int cached_only = 0;
5 static int diff_output_format = DIFF_FORMAT_HUMAN;
6 static int match_nonexisting = 0;
7 static int detect_rename = 0;
8 static int reverse_diff = 0;
9 static int diff_score_opt = 0;
10 static const char *pickaxe = NULL;
11
12 /* A file entry went away or appeared */
13 static void show_file(const char *prefix, struct cache_entry *ce, unsigned char *sha1, unsigned int mode)
14 {
15         diff_addremove(prefix[0], ntohl(mode), sha1, ce->name, NULL);
16 }
17
18 static int get_stat_data(struct cache_entry *ce, 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             detect_rename < DIFF_DETECT_COPY)
75                 return 0;
76
77         mode = ntohl(mode);
78         oldmode = ntohl(oldmode);
79
80         diff_change(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)
86 {
87         while (entries) {
88                 struct cache_entry *ce = *ac;
89                 int same = (entries > 1) && ce_same_name(ce, ac[1]);
90
91                 switch (ce_stage(ce)) {
92                 case 0:
93                         /* No stage 1 entry? That means it's a new file */
94                         if (!same) {
95                                 show_new_file(ce);
96                                 break;
97                         }
98                         /* Show difference between old and new */
99                         show_modified(ac[1], ce, 1);
100                         break;
101                 case 1:
102                         /* No stage 3 (merge) entry? That means it's been deleted */
103                         if (!same) {
104                                 show_file("-", ce, ce->sha1, ce->ce_mode);
105                                 break;
106                         }
107                         /* We come here with ce pointing at stage 1
108                          * (original tree) and ac[1] pointing at stage
109                          * 3 (unmerged).  show-modified with
110                          * report-mising set to false does not say the
111                          * file is deleted but reports true if work
112                          * tree does not have it, in which case we
113                          * fall through to report the unmerged state.
114                          * Otherwise, we show the differences between
115                          * the original tree and the work tree.
116                          */
117                         if (!cached_only && !show_modified(ce, ac[1], 0))
118                                 break;
119                         /* fallthru */
120                 case 3:
121                         diff_unmerge(ce->name);
122                         break;
123
124                 default:
125                         die("impossible cache entry stage");
126                 }
127
128                 /*
129                  * Ignore all the different stages for this file,
130                  * we've handled the relevant cases now.
131                  */
132                 do {
133                         ac++;
134                         entries--;
135                 } while (entries && ce_same_name(ce, ac[0]));
136         }
137         return 0;
138 }
139
140 /*
141  * This turns all merge entries into "stage 3". That guarantees that
142  * when we read in the new tree (into "stage 1"), we won't lose sight
143  * of the fact that we had unmerged entries.
144  */
145 static void mark_merge_entries(void)
146 {
147         int i;
148         for (i = 0; i < active_nr; i++) {
149                 struct cache_entry *ce = active_cache[i];
150                 if (!ce_stage(ce))
151                         continue;
152                 ce->ce_flags |= htons(CE_STAGEMASK);
153         }
154 }
155
156 static char *diff_cache_usage =
157 "git-diff-cache [-p] [-r] [-z] [-m] [-M] [-C] [-R] [-S<string>] [--cached] <tree-ish> [<path>...]";
158
159 int main(int argc, const char **argv)
160 {
161         unsigned char tree_sha1[20];
162         void *tree;
163         unsigned long size;
164         int ret;
165
166         read_cache();
167         while (argc > 2) {
168                 const char *arg = argv[1];
169                 argv++;
170                 argc--;
171                 if (!strcmp(arg, "-r")) {
172                         /* We accept the -r flag just to look like git-diff-tree */
173                         continue;
174                 }
175                 if (!strcmp(arg, "-p")) {
176                         diff_output_format = DIFF_FORMAT_PATCH;
177                         continue;
178                 }
179                 if (!strncmp(arg, "-M", 2)) {
180                         detect_rename = DIFF_DETECT_RENAME;
181                         diff_score_opt = diff_scoreopt_parse(arg);
182                         continue;
183                 }
184                 if (!strncmp(arg, "-C", 2)) {
185                         detect_rename = DIFF_DETECT_COPY;
186                         diff_score_opt = diff_scoreopt_parse(arg);
187                         continue;
188                 }
189                 if (!strcmp(arg, "-z")) {
190                         diff_output_format = DIFF_FORMAT_MACHINE;
191                         continue;
192                 }
193                 if (!strcmp(arg, "-R")) {
194                         reverse_diff = 1;
195                         continue;
196                 }
197                 if (!strcmp(arg, "-S")) {
198                         pickaxe = arg + 2;
199                         continue;
200                 }
201                 if (!strcmp(arg, "-m")) {
202                         match_nonexisting = 1;
203                         continue;
204                 }
205                 if (!strcmp(arg, "--cached")) {
206                         cached_only = 1;
207                         continue;
208                 }
209                 usage(diff_cache_usage);
210         }
211
212         if (argc < 2 || get_sha1(argv[1], tree_sha1))
213                 usage(diff_cache_usage);
214         argv++;
215         argc--;
216
217         /* The rest is for paths restriction. */
218
219         diff_setup(reverse_diff);
220
221         mark_merge_entries();
222
223         tree = read_object_with_reference(tree_sha1, "tree", &size, NULL);
224         if (!tree)
225                 die("bad tree object %s", argv[1]);
226         if (read_tree(tree, size, 1))
227                 die("unable to read tree object %s", argv[1]);
228
229         ret = diff_cache(active_cache, active_nr);
230         if (detect_rename)
231                 diffcore_rename(detect_rename, diff_score_opt);
232         if (pickaxe)
233                 diffcore_pickaxe(pickaxe);
234         if (2 <= argc)
235                 diffcore_pathspec(argv + 1);
236         diff_flush(diff_output_format, 1);
237         return ret;
238 }