describe.c

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "tag.h"
   4 #include "refs.h"
   5
   6 #define SEEN (1u << 0)
   7
   8 static const char describe_usage[] =
   9 "git-describe [--all] [--tags] [--abbrev=<n>] <committish>*";
  10
  11 static int all = 0;     /* Default to annotated tags only */
  12 static int tags = 0;    /* But allow any tags if --tags is specified */
  13
  14 static int abbrev = DEFAULT_ABBREV;
  15
  16 static int names = 0, allocs = 0;
  17 static struct commit_name {
  18         const struct commit *commit;
  19         int prio; /* annotated tag = 2, tag = 1, head = 0 */
  20         char path[FLEX_ARRAY]; /* more */
  21 } **name_array = NULL;
  22
  23 static 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
  36 static void add_to_known_names(const char *path,
  37                                const struct commit *commit,
  38                                int prio)
  39 {
  40         int idx;
  41         int len = strlen(path)+1;
  42         struct commit_name *name = xmalloc(sizeof(struct commit_name) + len);
  43
  44         name->commit = commit;
  45         name->prio = prio;
  46         memcpy(name->path, path, len);
  47         idx = names;
  48         if (idx >= allocs) {
  49                 allocs = (idx + 50) * 3 / 2;
  50                 name_array = xrealloc(name_array, allocs*sizeof(*name_array));
  51         }
  52         name_array[idx] = name;
  53         names = ++idx;
  54 }
  55
  56 static int get_name(const char *path, const unsigned char *sha1)
  57 {
  58         struct commit *commit = lookup_commit_reference_gently(sha1, 1);
  59         struct object *object;
  60         int prio;
  61
  62         if (!commit)
  63                 return 0;
  64         object = parse_object(sha1);
  65         /* If --all, then any refs are used.
  66          * If --tags, then any tags are used.
  67          * Otherwise only annotated tags are used.
  68          */
  69         if (!strncmp(path, "refs/tags/", 10)) {
  70                 if (object->type == tag_type)
  71                         prio = 2;
  72                 else
  73                         prio = 1;
  74         }
  75         else
  76                 prio = 0;
  77
  78         if (!all) {
  79                 if (!prio)
  80                         return 0;
  81                 if (!tags && prio < 2)
  82                         return 0;
  83         }
  84         add_to_known_names(all ? path + 5 : path + 10, commit, prio);
  85         return 0;
  86 }
  87
  88 static int compare_names(const void *_a, const void *_b)
  89 {
  90         struct commit_name *a = *(struct commit_name **)_a;
  91         struct commit_name *b = *(struct commit_name **)_b;
  92         unsigned long a_date = a->commit->date;
  93         unsigned long b_date = b->commit->date;
  94
  95         if (a->prio != b->prio)
  96                 return b->prio - a->prio;
  97         return (a_date > b_date) ? -1 : (a_date == b_date) ? 0 : 1;
  98 }
  99
 100 static void describe(char *arg, int last_one)
 101 {
 102         unsigned char sha1[20];
 103         struct commit *cmit;
 104         struct commit_list *list;
 105         static int initialized = 0;
 106         struct commit_name *n;
 107
 108         if (get_sha1(arg, sha1) < 0)
 109                 usage(describe_usage);
 110         cmit = lookup_commit_reference(sha1);
 111         if (!cmit)
 112                 usage(describe_usage);
 113
 114         if (!initialized) {
 115                 initialized = 1;
 116                 for_each_ref(get_name);
 117                 qsort(name_array, names, sizeof(*name_array), compare_names);
 118         }
 119
 120         n = match(cmit);
 121         if (n) {
 122                 printf("%s\n", n->path);
 123                 return;
 124         }
 125
 126         list = NULL;
 127         commit_list_insert(cmit, &list);
 128         while (list) {
 129                 struct commit *c = pop_most_recent_commit(&list, SEEN);
 130                 n = match(c);
 131                 if (n) {
 132                         printf("%s-g%s\n", n->path,
 133                                find_unique_abbrev(cmit->object.sha1, abbrev));
 134                         if (!last_one)
 135                                 clear_commit_marks(cmit, SEEN);
 136                         return;
 137                 }
 138         }
 139         die("cannot describe '%s'", sha1_to_hex(cmit->object.sha1));
 140 }
 141
 142 int main(int argc, char **argv)
 143 {
 144         int i;
 145
 146         for (i = 1; i < argc; i++) {
 147                 const char *arg = argv[i];
 148
 149                 if (*arg != '-')
 150                         break;
 151                 else if (!strcmp(arg, "--all"))
 152                         all = 1;
 153                 else if (!strcmp(arg, "--tags"))
 154                         tags = 1;
 155                 else if (!strncmp(arg, "--abbrev=", 9)) {
 156                         abbrev = strtoul(arg + 9, NULL, 10);
 157                         if (abbrev < MINIMUM_ABBREV || 40 <= abbrev)
 158                                 abbrev = DEFAULT_ABBREV;
 159                 }
 160                 else
 161                         usage(describe_usage);
 162         }
 163
 164         if (i == argc)
 165                 describe("HEAD", 1);
 166         else
 167                 while (i < argc) {
 168                         describe(argv[i], (i == argc - 1));
 169                         i++;
 170                 }
 171
 172         return 0;
 173 }