git-describe: use find_unique_abbrev()
[git/git.git] / describe.c
CommitLineData
908e5310
LT
1#include "cache.h"
2#include "commit.h"
635d4134 3#include "tag.h"
908e5310
LT
4#include "refs.h"
5
6#define SEEN (1u << 0)
7
8static const char describe_usage[] = "git-describe [--all] <committish>*";
9
635d4134 10static int all = 0; /* Default to annotated tags only */
908e5310
LT
11
12static int names = 0, allocs = 0;
13static struct commit_name {
14 const struct commit *commit;
15 char path[];
16} **name_array = NULL;
17
18static struct commit_name *match(struct commit *cmit)
19{
20 int i = names;
21 struct commit_name **p = name_array;
22
23 while (i-- > 0) {
24 struct commit_name *n = *p++;
25 if (n->commit == cmit)
26 return n;
27 }
28 return NULL;
29}
30
31static void add_to_known_names(const char *path, const struct commit *commit)
32{
33 int idx;
34 int len = strlen(path)+1;
35 struct commit_name *name = xmalloc(sizeof(struct commit_name) + len);
36
37 name->commit = commit;
38 memcpy(name->path, path, len);
39 idx = names;
40 if (idx >= allocs) {
41 allocs = (idx + 50) * 3 / 2;
42 name_array = xrealloc(name_array, allocs*sizeof(*name_array));
43 }
44 name_array[idx] = name;
45 names = ++idx;
46}
47
48static int get_name(const char *path, const unsigned char *sha1)
49{
50 struct commit *commit = lookup_commit_reference_gently(sha1, 1);
51 if (!commit)
52 return 0;
635d4134
JH
53 if (!all) {
54 struct object *object;
55 if (strncmp(path, "refs/tags/", 10))
56 return 0;
57 object = parse_object(sha1);
58 if (object->type != tag_type)
59 return 0;
60 }
61 add_to_known_names(all ? path : path + 10, commit);
908e5310
LT
62 return 0;
63}
64
65static int compare_names(const void *_a, const void *_b)
66{
67 struct commit_name *a = *(struct commit_name **)_a;
68 struct commit_name *b = *(struct commit_name **)_b;
69 unsigned long a_date = a->commit->date;
70 unsigned long b_date = b->commit->date;
71 return (a_date > b_date) ? -1 : (a_date == b_date) ? 0 : 1;
72}
73
74static void describe(struct commit *cmit)
75{
76 struct commit_list *list;
77 static int initialized = 0;
78 struct commit_name *n;
79
80 if (!initialized) {
81 initialized = 1;
82 for_each_ref(get_name);
83 qsort(name_array, names, sizeof(*name_array), compare_names);
84 }
85
86 n = match(cmit);
87 if (n) {
88 printf("%s\n", n->path);
89 return;
90 }
91
92 list = NULL;
93 commit_list_insert(cmit, &list);
94 while (list) {
95 struct commit *c = pop_most_recent_commit(&list, SEEN);
96 n = match(c);
97 if (n) {
4cdf78bf
JH
98 printf("%s-g%s\n", n->path,
99 find_unique_abbrev(cmit->object.sha1, 8));
908e5310
LT
100 return;
101 }
102 }
103}
104
105int main(int argc, char **argv)
106{
107 int i;
108
109 for (i = 1; i < argc; i++) {
110 const char *arg = argv[i];
111 unsigned char sha1[20];
112 struct commit *cmit;
113
114 if (!strcmp(arg, "--all")) {
115 all = 1;
116 continue;
117 }
118 if (get_sha1(arg, sha1) < 0)
119 usage(describe_usage);
120 cmit = lookup_commit_reference(sha1);
121 if (!cmit)
122 usage(describe_usage);
123 describe(cmit);
124 }
125 return 0;
126}