git-describe: --tags and --abbrev
[git/git.git] / describe.c
CommitLineData
908e5310
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1#include "cache.h"
2#include "commit.h"
635d4134 3#include "tag.h"
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4#include "refs.h"
5
6#define SEEN (1u << 0)
7
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8static const char describe_usage[] =
9"git-describe [--all] [--tags] [--abbrev=<n>] <committish>*";
908e5310 10
635d4134 11static int all = 0; /* Default to annotated tags only */
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12static int tags = 0; /* But allow any tags if --tags is specified */
13
14#define DEFAULT_ABBREV 8 /* maybe too many */
15static int abbrev = DEFAULT_ABBREV;
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16
17static int names = 0, allocs = 0;
18static struct commit_name {
19 const struct commit *commit;
20 char path[];
21} **name_array = NULL;
22
23static struct commit_name *match(struct commit *cmit)
24{
25 int i = names;
26 struct commit_name **p = name_array;
27
28 while (i-- > 0) {
29 struct commit_name *n = *p++;
30 if (n->commit == cmit)
31 return n;
32 }
33 return NULL;
34}
35
36static void add_to_known_names(const char *path, const struct commit *commit)
37{
38 int idx;
39 int len = strlen(path)+1;
40 struct commit_name *name = xmalloc(sizeof(struct commit_name) + len);
41
42 name->commit = commit;
43 memcpy(name->path, path, len);
44 idx = names;
45 if (idx >= allocs) {
46 allocs = (idx + 50) * 3 / 2;
47 name_array = xrealloc(name_array, allocs*sizeof(*name_array));
48 }
49 name_array[idx] = name;
50 names = ++idx;
51}
52
53static int get_name(const char *path, const unsigned char *sha1)
54{
55 struct commit *commit = lookup_commit_reference_gently(sha1, 1);
56 if (!commit)
57 return 0;
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58 /* If --all, then any refs are used.
59 * If --tags, then any tags are used.
60 * Otherwise only annotated tags are used.
61 */
635d4134 62 if (!all) {
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63 if (strncmp(path, "refs/tags/", 10))
64 return 0;
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65 if (!tags) {
66 struct object *object;
67 object = parse_object(sha1);
68 if (object->type != tag_type)
69 return 0;
70 }
635d4134
JH
71 }
72 add_to_known_names(all ? path : path + 10, commit);
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73 return 0;
74}
75
76static int compare_names(const void *_a, const void *_b)
77{
78 struct commit_name *a = *(struct commit_name **)_a;
79 struct commit_name *b = *(struct commit_name **)_b;
80 unsigned long a_date = a->commit->date;
81 unsigned long b_date = b->commit->date;
82 return (a_date > b_date) ? -1 : (a_date == b_date) ? 0 : 1;
83}
84
85static void describe(struct commit *cmit)
86{
87 struct commit_list *list;
88 static int initialized = 0;
89 struct commit_name *n;
90
91 if (!initialized) {
92 initialized = 1;
93 for_each_ref(get_name);
94 qsort(name_array, names, sizeof(*name_array), compare_names);
95 }
96
97 n = match(cmit);
98 if (n) {
99 printf("%s\n", n->path);
100 return;
101 }
102
103 list = NULL;
104 commit_list_insert(cmit, &list);
105 while (list) {
106 struct commit *c = pop_most_recent_commit(&list, SEEN);
107 n = match(c);
108 if (n) {
4cdf78bf 109 printf("%s-g%s\n", n->path,
2d9e7c9f 110 find_unique_abbrev(cmit->object.sha1, abbrev));
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111 return;
112 }
113 }
114}
115
116int main(int argc, char **argv)
117{
118 int i;
119
120 for (i = 1; i < argc; i++) {
121 const char *arg = argv[i];
122 unsigned char sha1[20];
123 struct commit *cmit;
124
125 if (!strcmp(arg, "--all")) {
126 all = 1;
127 continue;
128 }
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JH
129 if (!strcmp(arg, "--tags")) {
130 tags = 1;
131 continue;
132 }
133 if (!strncmp(arg, "--abbrev=", 9)) {
134 abbrev = strtoul(arg + 9, NULL, 10);
135 if (abbrev < 4 || 40 <= abbrev)
136 abbrev = DEFAULT_ABBREV;
137 continue;
138 }
908e5310
LT
139 if (get_sha1(arg, sha1) < 0)
140 usage(describe_usage);
141 cmit = lookup_commit_reference(sha1);
142 if (!cmit)
143 usage(describe_usage);
144 describe(cmit);
145 }
146 return 0;
147}