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 #define DEFAULT_ABBREV 8 /* maybe too many */
  15 static int abbrev = DEFAULT_ABBREV;
  16
  17 static int names = 0, allocs = 0;
  18 static struct commit_name {
  19         const struct commit *commit;
  20         char path[];
  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, 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
  53 static 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;
  58         /* If --all, then any refs are used.
  59          * If --tags, then any tags are used.
  60          * Otherwise only annotated tags are used.
  61          */
  62         if (!all) {
  63                 if (strncmp(path, "refs/tags/", 10))
  64                         return 0;
  65                 if (!tags) {
  66                         struct object *object;
  67                         object = parse_object(sha1);
  68                         if (object->type != tag_type)
  69                                 return 0;
  70                 }
  71         }
  72         add_to_known_names(all ? path : path + 10, commit);
  73         return 0;
  74 }
  75
  76 static 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
  85 static 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) {
 109                         printf("%s-g%s\n", n->path,
 110                                find_unique_abbrev(cmit->object.sha1, abbrev));
 111                         return;
 112                 }
 113         }
 114 }
 115
 116 int 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                 }
 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                 }
 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 }