Teach git-describe to use peeled ref information when scanning tags
[git] / builtin-name-rev.c
1 #include "builtin.h"
2 #include "cache.h"
3 #include "commit.h"
4 #include "tag.h"
5 #include "refs.h"
6 #include "parse-options.h"
7
8 #define CUTOFF_DATE_SLOP 86400 /* one day */
9
10 typedef struct rev_name {
11         const char *tip_name;
12         int generation;
13         int distance;
14 } rev_name;
15
16 static long cutoff = LONG_MAX;
17
18 /* How many generations are maximally preferred over _one_ merge traversal? */
19 #define MERGE_TRAVERSAL_WEIGHT 65535
20
21 static void name_rev(struct commit *commit,
22                 const char *tip_name, int generation, int distance,
23                 int deref)
24 {
25         struct rev_name *name = (struct rev_name *)commit->util;
26         struct commit_list *parents;
27         int parent_number = 1;
28
29         if (!commit->object.parsed)
30                 parse_commit(commit);
31
32         if (commit->date < cutoff)
33                 return;
34
35         if (deref) {
36                 char *new_name = xmalloc(strlen(tip_name)+3);
37                 strcpy(new_name, tip_name);
38                 strcat(new_name, "^0");
39                 tip_name = new_name;
40
41                 if (generation)
42                         die("generation: %d, but deref?", generation);
43         }
44
45         if (name == NULL) {
46                 name = xmalloc(sizeof(rev_name));
47                 commit->util = name;
48                 goto copy_data;
49         } else if (name->distance > distance) {
50 copy_data:
51                 name->tip_name = tip_name;
52                 name->generation = generation;
53                 name->distance = distance;
54         } else
55                 return;
56
57         for (parents = commit->parents;
58                         parents;
59                         parents = parents->next, parent_number++) {
60                 if (parent_number > 1) {
61                         int len = strlen(tip_name);
62                         char *new_name = xmalloc(len +
63                                 1 + decimal_length(generation) +  /* ~<n> */
64                                 1 + 2 +                           /* ^NN */
65                                 1);
66
67                         if (len > 2 && !strcmp(tip_name + len - 2, "^0"))
68                                 len -= 2;
69                         if (generation > 0)
70                                 sprintf(new_name, "%.*s~%d^%d", len, tip_name,
71                                                 generation, parent_number);
72                         else
73                                 sprintf(new_name, "%.*s^%d", len, tip_name,
74                                                 parent_number);
75
76                         name_rev(parents->item, new_name, 0,
77                                 distance + MERGE_TRAVERSAL_WEIGHT, 0);
78                 } else {
79                         name_rev(parents->item, tip_name, generation + 1,
80                                 distance + 1, 0);
81                 }
82         }
83 }
84
85 struct name_ref_data {
86         int tags_only;
87         int name_only;
88         const char *ref_filter;
89 };
90
91 static int name_ref(const char *path, const unsigned char *sha1, int flags, void *cb_data)
92 {
93         struct object *o = parse_object(sha1);
94         struct name_ref_data *data = cb_data;
95         int deref = 0;
96
97         if (data->tags_only && prefixcmp(path, "refs/tags/"))
98                 return 0;
99
100         if (data->ref_filter && fnmatch(data->ref_filter, path, 0))
101                 return 0;
102
103         while (o && o->type == OBJ_TAG) {
104                 struct tag *t = (struct tag *) o;
105                 if (!t->tagged)
106                         break; /* broken repository */
107                 o = parse_object(t->tagged->sha1);
108                 deref = 1;
109         }
110         if (o && o->type == OBJ_COMMIT) {
111                 struct commit *commit = (struct commit *)o;
112
113                 if (!prefixcmp(path, "refs/heads/"))
114                         path = path + 11;
115                 else if (data->tags_only
116                     && data->name_only
117                     && !prefixcmp(path, "refs/tags/"))
118                         path = path + 10;
119                 else if (!prefixcmp(path, "refs/"))
120                         path = path + 5;
121
122                 name_rev(commit, xstrdup(path), 0, 0, deref);
123         }
124         return 0;
125 }
126
127 /* returns a static buffer */
128 static const char *get_rev_name(struct object *o)
129 {
130         static char buffer[1024];
131         struct rev_name *n;
132         struct commit *c;
133
134         if (o->type != OBJ_COMMIT)
135                 return NULL;
136         c = (struct commit *) o;
137         n = c->util;
138         if (!n)
139                 return NULL;
140
141         if (!n->generation)
142                 return n->tip_name;
143         else {
144                 int len = strlen(n->tip_name);
145                 if (len > 2 && !strcmp(n->tip_name + len - 2, "^0"))
146                         len -= 2;
147                 snprintf(buffer, sizeof(buffer), "%.*s~%d", len, n->tip_name,
148                                 n->generation);
149
150                 return buffer;
151         }
152 }
153
154 static char const * const name_rev_usage[] = {
155         "git-name-rev [options] ( --all | --stdin | <commit>... )",
156         NULL
157 };
158
159 int cmd_name_rev(int argc, const char **argv, const char *prefix)
160 {
161         struct object_array revs = { 0, 0, NULL };
162         int all = 0, transform_stdin = 0, allow_undefined = 1;
163         struct name_ref_data data = { 0, 0, NULL };
164         struct option opts[] = {
165                 OPT_BOOLEAN(0, "name-only", &data.name_only, "print only names (no SHA-1)"),
166                 OPT_BOOLEAN(0, "tags", &data.tags_only, "only use tags to name the commits"),
167                 OPT_STRING(0, "refs", &data.ref_filter, "pattern",
168                                    "only use refs matching <pattern>"),
169                 OPT_GROUP(""),
170                 OPT_BOOLEAN(0, "all", &all, "list all commits reachable from all refs"),
171                 OPT_BOOLEAN(0, "stdin", &transform_stdin, "read from stdin"),
172                 OPT_BOOLEAN(0, "undefined", &allow_undefined, "allow to print `undefined` names"),
173                 OPT_END(),
174         };
175
176         git_config(git_default_config);
177         argc = parse_options(argc, argv, opts, name_rev_usage, 0);
178         if (!!all + !!transform_stdin + !!argc > 1) {
179                 error("Specify either a list, or --all, not both!");
180                 usage_with_options(name_rev_usage, opts);
181         }
182         if (all || transform_stdin)
183                 cutoff = 0;
184
185         for (; argc; argc--, argv++) {
186                 unsigned char sha1[20];
187                 struct object *o;
188                 struct commit *commit;
189
190                 if (get_sha1(*argv, sha1)) {
191                         fprintf(stderr, "Could not get sha1 for %s. Skipping.\n",
192                                         *argv);
193                         continue;
194                 }
195
196                 o = deref_tag(parse_object(sha1), *argv, 0);
197                 if (!o || o->type != OBJ_COMMIT) {
198                         fprintf(stderr, "Could not get commit for %s. Skipping.\n",
199                                         *argv);
200                         continue;
201                 }
202
203                 commit = (struct commit *)o;
204                 if (cutoff > commit->date)
205                         cutoff = commit->date;
206                 add_object_array((struct object *)commit, *argv, &revs);
207         }
208
209         if (cutoff)
210                 cutoff = cutoff - CUTOFF_DATE_SLOP;
211         for_each_ref(name_ref, &data);
212
213         if (transform_stdin) {
214                 char buffer[2048];
215                 char *p, *p_start;
216
217                 while (!feof(stdin)) {
218                         int forty = 0;
219                         p = fgets(buffer, sizeof(buffer), stdin);
220                         if (!p)
221                                 break;
222
223                         for (p_start = p; *p; p++) {
224 #define ishex(x) (isdigit((x)) || ((x) >= 'a' && (x) <= 'f'))
225                                 if (!ishex(*p))
226                                         forty = 0;
227                                 else if (++forty == 40 &&
228                                                 !ishex(*(p+1))) {
229                                         unsigned char sha1[40];
230                                         const char *name = NULL;
231                                         char c = *(p+1);
232
233                                         forty = 0;
234
235                                         *(p+1) = 0;
236                                         if (!get_sha1(p - 39, sha1)) {
237                                                 struct object *o =
238                                                         lookup_object(sha1);
239                                                 if (o)
240                                                         name = get_rev_name(o);
241                                         }
242                                         *(p+1) = c;
243
244                                         if (!name)
245                                                 continue;
246
247                                         fwrite(p_start, p - p_start + 1, 1, stdout);
248                                         printf(" (%s)", name);
249                                         p_start = p + 1;
250                                 }
251                         }
252
253                         /* flush */
254                         if (p_start != p)
255                                 fwrite(p_start, p - p_start, 1, stdout);
256                 }
257         } else if (all) {
258                 int i, max;
259
260                 max = get_max_object_index();
261                 for (i = 0; i < max; i++) {
262                         struct object * obj = get_indexed_object(i);
263                         const char *name;
264                         if (!obj)
265                                 continue;
266                         if (!data.name_only)
267                                 printf("%s ", sha1_to_hex(obj->sha1));
268                         name = get_rev_name(obj);
269                         if (name)
270                                 printf("%s\n", name);
271                         else if (allow_undefined)
272                                 printf("undefined\n");
273                         else
274                                 die("cannot describe '%s'", sha1_to_hex(obj->sha1));
275                 }
276         } else {
277                 int i;
278                 for (i = 0; i < revs.nr; i++) {
279                         const char *name;
280                         if (!data.name_only)
281                                 printf("%s ", revs.objects[i].name);
282                         name = get_rev_name(revs.objects[i].item);
283                         if (name)
284                                 printf("%s\n", name);
285                         else if (allow_undefined)
286                                 printf("undefined\n");
287                         else
288                                 die("cannot describe '%s'", sha1_to_hex(revs.objects[i].item->sha1));
289                 }
290         }
291
292         return 0;
293 }