421658d3bea2121fcc1f599b8d664a6c01159b8b
[git/git.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
7 #define SEEN (1u<<0)
8 #define MAX_TAGS (FLAG_BITS - 1)
9
10 static const char describe_usage[] =
11 "git-describe [--all] [--tags] [--abbrev=<n>] <committish>*";
12
13 static int debug; /* Display lots of verbose info */
14 static int all; /* Default to annotated tags only */
15 static int tags; /* But allow any tags if --tags is specified */
16 static int abbrev = DEFAULT_ABBREV;
17 static int max_candidates = 10;
18
19 static unsigned int names[256], allocs[256];
20 static struct commit_name {
21 struct commit *commit;
22 int prio; /* annotated tag = 2, tag = 1, head = 0 */
23 char path[FLEX_ARRAY]; /* more */
24 } **name_array[256];
25
26 static struct commit_name *match(struct commit *cmit)
27 {
28 unsigned char level0 = cmit->object.sha1[0];
29 struct commit_name **p = name_array[level0];
30 unsigned int hi = names[level0];
31 unsigned int lo = 0;
32
33 while (lo < hi) {
34 unsigned int mi = (lo + hi) / 2;
35 int cmp = hashcmp(p[mi]->commit->object.sha1,
36 cmit->object.sha1);
37 if (!cmp) {
38 while (mi && p[mi - 1]->commit == cmit)
39 mi--;
40 return p[mi];
41 }
42 if (cmp > 0)
43 hi = mi;
44 else
45 lo = mi+1;
46 }
47 return NULL;
48 }
49
50 static void add_to_known_names(const char *path,
51 struct commit *commit,
52 int prio)
53 {
54 int idx;
55 int len = strlen(path)+1;
56 struct commit_name *name = xmalloc(sizeof(struct commit_name) + len);
57 unsigned char m = commit->object.sha1[0];
58
59 name->commit = commit;
60 name->prio = prio;
61 memcpy(name->path, path, len);
62 idx = names[m];
63 if (idx >= allocs[m]) {
64 allocs[m] = (idx + 50) * 3 / 2;
65 name_array[m] = xrealloc(name_array[m],
66 allocs[m] * sizeof(*name_array));
67 }
68 name_array[m][idx] = name;
69 names[m] = ++idx;
70 }
71
72 static int get_name(const char *path, const unsigned char *sha1, int flag, void *cb_data)
73 {
74 struct commit *commit = lookup_commit_reference_gently(sha1, 1);
75 struct object *object;
76 int prio;
77
78 if (!commit)
79 return 0;
80 object = parse_object(sha1);
81 /* If --all, then any refs are used.
82 * If --tags, then any tags are used.
83 * Otherwise only annotated tags are used.
84 */
85 if (!strncmp(path, "refs/tags/", 10)) {
86 if (object->type == OBJ_TAG)
87 prio = 2;
88 else
89 prio = 1;
90 }
91 else
92 prio = 0;
93
94 if (!all) {
95 if (!prio)
96 return 0;
97 if (!tags && prio < 2)
98 return 0;
99 }
100 add_to_known_names(all ? path + 5 : path + 10, commit, prio);
101 return 0;
102 }
103
104 static int compare_names(const void *_a, const void *_b)
105 {
106 struct commit_name *a = *(struct commit_name **)_a;
107 struct commit_name *b = *(struct commit_name **)_b;
108 unsigned long a_date = a->commit->date;
109 unsigned long b_date = b->commit->date;
110 int cmp = hashcmp(a->commit->object.sha1, b->commit->object.sha1);
111
112 if (cmp)
113 return cmp;
114 if (a->prio != b->prio)
115 return b->prio - a->prio;
116 return (a_date > b_date) ? -1 : (a_date == b_date) ? 0 : 1;
117 }
118
119 struct possible_tag {
120 struct commit_name *name;
121 unsigned long depth;
122 unsigned flag_within;
123 };
124
125 static void describe(const char *arg, int last_one)
126 {
127 unsigned char sha1[20];
128 struct commit *cmit, *gave_up_on = NULL;
129 struct commit_list *list;
130 static int initialized = 0;
131 struct commit_name *n;
132 struct possible_tag all_matches[MAX_TAGS], *min_match;
133 unsigned int match_cnt = 0, annotated_cnt = 0, cur_match;
134 unsigned long seen_commits = 0;
135
136 if (get_sha1(arg, sha1))
137 die("Not a valid object name %s", arg);
138 cmit = lookup_commit_reference(sha1);
139 if (!cmit)
140 die("%s is not a valid '%s' object", arg, commit_type);
141
142 if (!initialized) {
143 unsigned int m;
144 initialized = 1;
145 for_each_ref(get_name, NULL);
146 for (m = 0; m < ARRAY_SIZE(name_array); m++)
147 qsort(name_array[m], names[m],
148 sizeof(*name_array[m]), compare_names);
149 }
150
151 n = match(cmit);
152 if (n) {
153 printf("%s\n", n->path);
154 return;
155 }
156
157 if (debug)
158 fprintf(stderr, "searching to describe %s\n", arg);
159
160 list = NULL;
161 cmit->object.flags = SEEN;
162 commit_list_insert(cmit, &list);
163 while (list) {
164 struct commit *c = pop_commit(&list);
165 struct commit_list *parents = c->parents;
166 seen_commits++;
167 n = match(c);
168 if (n) {
169 if (match_cnt < max_candidates) {
170 struct possible_tag *t = &all_matches[match_cnt++];
171 t->name = n;
172 t->depth = seen_commits - 1;
173 t->flag_within = 1u << match_cnt;
174 c->object.flags |= t->flag_within;
175 if (n->prio == 2)
176 annotated_cnt++;
177 }
178 else {
179 gave_up_on = c;
180 break;
181 }
182 }
183 for (cur_match = 0; cur_match < match_cnt; cur_match++) {
184 struct possible_tag *t = &all_matches[cur_match];
185 if (!(c->object.flags & t->flag_within))
186 t->depth++;
187 }
188 if (annotated_cnt && !list) {
189 if (debug)
190 fprintf(stderr, "finished search at %s\n",
191 sha1_to_hex(c->object.sha1));
192 break;
193 }
194 while (parents) {
195 struct commit *p = parents->item;
196 parse_commit(p);
197 if (!(p->object.flags & SEEN))
198 insert_by_date(p, &list);
199 p->object.flags |= c->object.flags;
200 parents = parents->next;
201 }
202 }
203 free_commit_list(list);
204
205 if (!match_cnt)
206 die("cannot describe '%s'", sha1_to_hex(cmit->object.sha1));
207
208 min_match = &all_matches[0];
209 for (cur_match = 1; cur_match < match_cnt; cur_match++) {
210 struct possible_tag *t = &all_matches[cur_match];
211 if (t->depth < min_match->depth
212 && t->name->prio >= min_match->name->prio)
213 min_match = t;
214 }
215 if (debug) {
216 for (cur_match = 0; cur_match < match_cnt; cur_match++) {
217 struct possible_tag *t = &all_matches[cur_match];
218 fprintf(stderr, " %c %8lu %s\n",
219 min_match == t ? '*' : ' ',
220 t->depth, t->name->path);
221 }
222 fprintf(stderr, "traversed %lu commits\n", seen_commits);
223 if (gave_up_on) {
224 fprintf(stderr,
225 "more than %i tags found; listed %i most recent\n"
226 "gave up search at %s\n",
227 max_candidates, max_candidates,
228 sha1_to_hex(gave_up_on->object.sha1));
229 }
230 }
231 printf("%s-g%s\n", min_match->name->path,
232 find_unique_abbrev(cmit->object.sha1, abbrev));
233
234 if (!last_one)
235 clear_commit_marks(cmit, -1);
236 }
237
238 int cmd_describe(int argc, const char **argv, const char *prefix)
239 {
240 int i;
241
242 for (i = 1; i < argc; i++) {
243 const char *arg = argv[i];
244
245 if (*arg != '-')
246 break;
247 else if (!strcmp(arg, "--debug"))
248 debug = 1;
249 else if (!strcmp(arg, "--all"))
250 all = 1;
251 else if (!strcmp(arg, "--tags"))
252 tags = 1;
253 else if (!strncmp(arg, "--abbrev=", 9)) {
254 abbrev = strtoul(arg + 9, NULL, 10);
255 if (abbrev < MINIMUM_ABBREV || 40 < abbrev)
256 abbrev = DEFAULT_ABBREV;
257 }
258 else if (!strncmp(arg, "--candidates=", 13)) {
259 max_candidates = strtoul(arg + 13, NULL, 10);
260 if (max_candidates < 1)
261 max_candidates = 1;
262 else if (max_candidates > MAX_TAGS)
263 max_candidates = MAX_TAGS;
264 }
265 else
266 usage(describe_usage);
267 }
268
269 save_commit_buffer = 0;
270
271 if (argc <= i)
272 describe("HEAD", 1);
273 else
274 while (i < argc) {
275 describe(argv[i], (i == argc - 1));
276 i++;
277 }
278
279 return 0;
280 }