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[git] / builtin-describe.c
1 #include "cache.h"
2 #include "commit.h"
3 #include "tag.h"
4 #include "refs.h"
5 #include "builtin.h"
6 #include "exec_cmd.h"
7 #include "parse-options.h"
8
9 #define SEEN            (1u<<0)
10 #define MAX_TAGS        (FLAG_BITS - 1)
11
12 static const char * const describe_usage[] = {
13         "git-describe [options] <committish>*",
14         NULL
15 };
16
17 static int debug;       /* Display lots of verbose info */
18 static int all; /* Default to annotated tags only */
19 static int tags;        /* But allow any tags if --tags is specified */
20 static int longformat;
21 static int abbrev = DEFAULT_ABBREV;
22 static int max_candidates = 10;
23 const char *pattern = NULL;
24 static int always;
25
26 struct commit_name {
27         struct tag *tag;
28         int prio; /* annotated tag = 2, tag = 1, head = 0 */
29         unsigned char sha1[20];
30         char path[FLEX_ARRAY]; /* more */
31 };
32 static const char *prio_names[] = {
33         "head", "lightweight", "annotated",
34 };
35
36 static void add_to_known_names(const char *path,
37                                struct commit *commit,
38                                int prio,
39                                const unsigned char *sha1)
40 {
41         struct commit_name *e = commit->util;
42         if (!e || e->prio < prio) {
43                 size_t len = strlen(path)+1;
44                 free(e);
45                 e = xmalloc(sizeof(struct commit_name) + len);
46                 e->tag = NULL;
47                 e->prio = prio;
48                 hashcpy(e->sha1, sha1);
49                 memcpy(e->path, path, len);
50                 commit->util = e;
51         }
52 }
53
54 static int get_name(const char *path, const unsigned char *sha1, int flag, void *cb_data)
55 {
56         int might_be_tag = !prefixcmp(path, "refs/tags/");
57         struct commit *commit;
58         struct object *object;
59         unsigned char peeled[20];
60         int is_tag, prio;
61
62         if (!all && !might_be_tag)
63                 return 0;
64
65         if (!peel_ref(path, peeled) && !is_null_sha1(peeled)) {
66                 commit = lookup_commit_reference_gently(peeled, 1);
67                 if (!commit)
68                         return 0;
69                 is_tag = !!hashcmp(sha1, commit->object.sha1);
70         } else {
71                 commit = lookup_commit_reference_gently(sha1, 1);
72                 object = parse_object(sha1);
73                 if (!commit || !object)
74                         return 0;
75                 is_tag = object->type == OBJ_TAG;
76         }
77
78         /* If --all, then any refs are used.
79          * If --tags, then any tags are used.
80          * Otherwise only annotated tags are used.
81          */
82         if (might_be_tag) {
83                 if (is_tag) {
84                         prio = 2;
85                         if (pattern && fnmatch(pattern, path + 10, 0))
86                                 prio = 0;
87                 } else
88                         prio = 1;
89         }
90         else
91                 prio = 0;
92
93         if (!all) {
94                 if (!prio)
95                         return 0;
96                 if (!tags && prio < 2)
97                         return 0;
98         }
99         add_to_known_names(all ? path + 5 : path + 10, commit, prio, sha1);
100         return 0;
101 }
102
103 struct possible_tag {
104         struct commit_name *name;
105         int depth;
106         int found_order;
107         unsigned flag_within;
108 };
109
110 static int compare_pt(const void *a_, const void *b_)
111 {
112         struct possible_tag *a = (struct possible_tag *)a_;
113         struct possible_tag *b = (struct possible_tag *)b_;
114         if (a->name->prio != b->name->prio)
115                 return b->name->prio - a->name->prio;
116         if (a->depth != b->depth)
117                 return a->depth - b->depth;
118         if (a->found_order != b->found_order)
119                 return a->found_order - b->found_order;
120         return 0;
121 }
122
123 static unsigned long finish_depth_computation(
124         struct commit_list **list,
125         struct possible_tag *best)
126 {
127         unsigned long seen_commits = 0;
128         while (*list) {
129                 struct commit *c = pop_commit(list);
130                 struct commit_list *parents = c->parents;
131                 seen_commits++;
132                 if (c->object.flags & best->flag_within) {
133                         struct commit_list *a = *list;
134                         while (a) {
135                                 struct commit *i = a->item;
136                                 if (!(i->object.flags & best->flag_within))
137                                         break;
138                                 a = a->next;
139                         }
140                         if (!a)
141                                 break;
142                 } else
143                         best->depth++;
144                 while (parents) {
145                         struct commit *p = parents->item;
146                         parse_commit(p);
147                         if (!(p->object.flags & SEEN))
148                                 insert_by_date(p, list);
149                         p->object.flags |= c->object.flags;
150                         parents = parents->next;
151                 }
152         }
153         return seen_commits;
154 }
155
156 static void display_name(struct commit_name *n)
157 {
158         if (n->prio == 2 && !n->tag) {
159                 n->tag = lookup_tag(n->sha1);
160                 if (!n->tag || parse_tag(n->tag) || !n->tag->tag)
161                         die("annotated tag %s not available", n->path);
162                 if (strcmp(n->tag->tag, n->path))
163                         warning("tag '%s' is really '%s' here", n->tag->tag, n->path);
164         }
165
166         if (n->tag)
167                 printf("%s", n->tag->tag);
168         else
169                 printf("%s", n->path);
170 }
171
172 static void show_suffix(int depth, const unsigned char *sha1)
173 {
174         printf("-%d-g%s", depth, find_unique_abbrev(sha1, abbrev));
175 }
176
177 static void describe(const char *arg, int last_one)
178 {
179         unsigned char sha1[20];
180         struct commit *cmit, *gave_up_on = NULL;
181         struct commit_list *list;
182         static int initialized = 0;
183         struct commit_name *n;
184         struct possible_tag all_matches[MAX_TAGS];
185         unsigned int match_cnt = 0, annotated_cnt = 0, cur_match;
186         unsigned long seen_commits = 0;
187
188         if (get_sha1(arg, sha1))
189                 die("Not a valid object name %s", arg);
190         cmit = lookup_commit_reference(sha1);
191         if (!cmit)
192                 die("%s is not a valid '%s' object", arg, commit_type);
193
194         if (!initialized) {
195                 initialized = 1;
196                 for_each_ref(get_name, NULL);
197         }
198
199         n = cmit->util;
200         if (n) {
201                 /*
202                  * Exact match to an existing ref.
203                  */
204                 display_name(n);
205                 if (longformat)
206                         show_suffix(0, n->tag->tagged->sha1);
207                 printf("\n");
208                 return;
209         }
210
211         if (!max_candidates)
212                 die("no tag exactly matches '%s'", sha1_to_hex(cmit->object.sha1));
213         if (debug)
214                 fprintf(stderr, "searching to describe %s\n", arg);
215
216         list = NULL;
217         cmit->object.flags = SEEN;
218         commit_list_insert(cmit, &list);
219         while (list) {
220                 struct commit *c = pop_commit(&list);
221                 struct commit_list *parents = c->parents;
222                 seen_commits++;
223                 n = c->util;
224                 if (n) {
225                         if (match_cnt < max_candidates) {
226                                 struct possible_tag *t = &all_matches[match_cnt++];
227                                 t->name = n;
228                                 t->depth = seen_commits - 1;
229                                 t->flag_within = 1u << match_cnt;
230                                 t->found_order = match_cnt;
231                                 c->object.flags |= t->flag_within;
232                                 if (n->prio == 2)
233                                         annotated_cnt++;
234                         }
235                         else {
236                                 gave_up_on = c;
237                                 break;
238                         }
239                 }
240                 for (cur_match = 0; cur_match < match_cnt; cur_match++) {
241                         struct possible_tag *t = &all_matches[cur_match];
242                         if (!(c->object.flags & t->flag_within))
243                                 t->depth++;
244                 }
245                 if (annotated_cnt && !list) {
246                         if (debug)
247                                 fprintf(stderr, "finished search at %s\n",
248                                         sha1_to_hex(c->object.sha1));
249                         break;
250                 }
251                 while (parents) {
252                         struct commit *p = parents->item;
253                         parse_commit(p);
254                         if (!(p->object.flags & SEEN))
255                                 insert_by_date(p, &list);
256                         p->object.flags |= c->object.flags;
257                         parents = parents->next;
258                 }
259         }
260
261         if (!match_cnt) {
262                 const unsigned char *sha1 = cmit->object.sha1;
263                 if (always) {
264                         printf("%s\n", find_unique_abbrev(sha1, abbrev));
265                         return;
266                 }
267                 die("cannot describe '%s'", sha1_to_hex(sha1));
268         }
269
270         qsort(all_matches, match_cnt, sizeof(all_matches[0]), compare_pt);
271
272         if (gave_up_on) {
273                 insert_by_date(gave_up_on, &list);
274                 seen_commits--;
275         }
276         seen_commits += finish_depth_computation(&list, &all_matches[0]);
277         free_commit_list(list);
278
279         if (debug) {
280                 for (cur_match = 0; cur_match < match_cnt; cur_match++) {
281                         struct possible_tag *t = &all_matches[cur_match];
282                         fprintf(stderr, " %-11s %8d %s\n",
283                                 prio_names[t->name->prio],
284                                 t->depth, t->name->path);
285                 }
286                 fprintf(stderr, "traversed %lu commits\n", seen_commits);
287                 if (gave_up_on) {
288                         fprintf(stderr,
289                                 "more than %i tags found; listed %i most recent\n"
290                                 "gave up search at %s\n",
291                                 max_candidates, max_candidates,
292                                 sha1_to_hex(gave_up_on->object.sha1));
293                 }
294         }
295
296         display_name(all_matches[0].name);
297         if (abbrev)
298                 show_suffix(all_matches[0].depth, cmit->object.sha1);
299         printf("\n");
300
301         if (!last_one)
302                 clear_commit_marks(cmit, -1);
303 }
304
305 int cmd_describe(int argc, const char **argv, const char *prefix)
306 {
307         int contains = 0;
308         struct option options[] = {
309                 OPT_BOOLEAN(0, "contains",   &contains, "find the tag that comes after the commit"),
310                 OPT_BOOLEAN(0, "debug",      &debug, "debug search strategy on stderr"),
311                 OPT_BOOLEAN(0, "all",        &all, "use any ref in .git/refs"),
312                 OPT_BOOLEAN(0, "tags",       &tags, "use any tag in .git/refs/tags"),
313                 OPT_BOOLEAN(0, "long",       &longformat, "always use long format"),
314                 OPT__ABBREV(&abbrev),
315                 OPT_SET_INT(0, "exact-match", &max_candidates,
316                             "only output exact matches", 0),
317                 OPT_INTEGER(0, "candidates", &max_candidates,
318                             "consider <n> most recent tags (default: 10)"),
319                 OPT_STRING(0, "match",       &pattern, "pattern",
320                            "only consider tags matching <pattern>"),
321                 OPT_BOOLEAN(0, "always",     &always,
322                            "show abbreviated commit object as fallback"),
323                 OPT_END(),
324         };
325
326         argc = parse_options(argc, argv, options, describe_usage, 0);
327         if (max_candidates < 0)
328                 max_candidates = 0;
329         else if (max_candidates > MAX_TAGS)
330                 max_candidates = MAX_TAGS;
331
332         save_commit_buffer = 0;
333
334         if (longformat && abbrev == 0)
335                 die("--long is incompatible with --abbrev=0");
336
337         if (contains) {
338                 const char **args = xmalloc((7 + argc) * sizeof(char*));
339                 int i = 0;
340                 args[i++] = "name-rev";
341                 args[i++] = "--name-only";
342                 args[i++] = "--no-undefined";
343                 if (always)
344                         args[i++] = "--always";
345                 if (!all) {
346                         args[i++] = "--tags";
347                         if (pattern) {
348                                 char *s = xmalloc(strlen("--refs=refs/tags/") + strlen(pattern) + 1);
349                                 sprintf(s, "--refs=refs/tags/%s", pattern);
350                                 args[i++] = s;
351                         }
352                 }
353                 memcpy(args + i, argv, argc * sizeof(char*));
354                 args[i + argc] = NULL;
355                 return cmd_name_rev(i + argc, args, prefix);
356         }
357
358         if (argc == 0) {
359                 describe("HEAD", 1);
360         } else {
361                 while (argc-- > 0) {
362                         describe(*argv++, argc == 0);
363                 }
364         }
365         return 0;
366 }