builtin-describe.c

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "tag.h"
   4 #include "refs.h"
   5 #include "builtin.h"
   6 #include "exec_cmd.h"
   7 #include "parse-options.h"
   8
   9 #define SEEN            (1u<<0)
  10 #define MAX_TAGS        (FLAG_BITS - 1)
  11
  12 static const char * const describe_usage[] = {
  13         "git-describe [options] <committish>*",
  14         NULL
  15 };
  16
  17 static int debug;       /* Display lots of verbose info */
  18 static int all; /* Default to annotated tags only */
  19 static int tags;        /* But allow any tags if --tags is specified */
  20 static int abbrev = DEFAULT_ABBREV;
  21 static int max_candidates = 10;
  22
  23 struct commit_name {
  24         int prio; /* annotated tag = 2, tag = 1, head = 0 */
  25         char path[FLEX_ARRAY]; /* more */
  26 };
  27 static const char *prio_names[] = {
  28         "head", "lightweight", "annotated",
  29 };
  30
  31 static void add_to_known_names(const char *path,
  32                                struct commit *commit,
  33                                int prio)
  34 {
  35         struct commit_name *e = commit->util;
  36         if (!e || e->prio < prio) {
  37                 size_t len = strlen(path)+1;
  38                 free(e);
  39                 e = xmalloc(sizeof(struct commit_name) + len);
  40                 e->prio = prio;
  41                 memcpy(e->path, path, len);
  42                 commit->util = e;
  43         }
  44 }
  45
  46 static int get_name(const char *path, const unsigned char *sha1, int flag, void *cb_data)
  47 {
  48         struct commit *commit = lookup_commit_reference_gently(sha1, 1);
  49         struct object *object;
  50         int prio;
  51
  52         if (!commit)
  53                 return 0;
  54         object = parse_object(sha1);
  55         /* If --all, then any refs are used.
  56          * If --tags, then any tags are used.
  57          * Otherwise only annotated tags are used.
  58          */
  59         if (!prefixcmp(path, "refs/tags/")) {
  60                 if (object->type == OBJ_TAG)
  61                         prio = 2;
  62                 else
  63                         prio = 1;
  64         }
  65         else
  66                 prio = 0;
  67
  68         if (!all) {
  69                 if (!prio)
  70                         return 0;
  71                 if (!tags && prio < 2)
  72                         return 0;
  73         }
  74         add_to_known_names(all ? path + 5 : path + 10, commit, prio);
  75         return 0;
  76 }
  77
  78 struct possible_tag {
  79         struct commit_name *name;
  80         int depth;
  81         int found_order;
  82         unsigned flag_within;
  83 };
  84
  85 static int compare_pt(const void *a_, const void *b_)
  86 {
  87         struct possible_tag *a = (struct possible_tag *)a_;
  88         struct possible_tag *b = (struct possible_tag *)b_;
  89         if (a->name->prio != b->name->prio)
  90                 return b->name->prio - a->name->prio;
  91         if (a->depth != b->depth)
  92                 return a->depth - b->depth;
  93         if (a->found_order != b->found_order)
  94                 return a->found_order - b->found_order;
  95         return 0;
  96 }
  97
  98 static unsigned long finish_depth_computation(
  99         struct commit_list **list,
 100         struct possible_tag *best)
 101 {
 102         unsigned long seen_commits = 0;
 103         while (*list) {
 104                 struct commit *c = pop_commit(list);
 105                 struct commit_list *parents = c->parents;
 106                 seen_commits++;
 107                 if (c->object.flags & best->flag_within) {
 108                         struct commit_list *a = *list;
 109                         while (a) {
 110                                 struct commit *i = a->item;
 111                                 if (!(i->object.flags & best->flag_within))
 112                                         break;
 113                                 a = a->next;
 114                         }
 115                         if (!a)
 116                                 break;
 117                 } else
 118                         best->depth++;
 119                 while (parents) {
 120                         struct commit *p = parents->item;
 121                         parse_commit(p);
 122                         if (!(p->object.flags & SEEN))
 123                                 insert_by_date(p, list);
 124                         p->object.flags |= c->object.flags;
 125                         parents = parents->next;
 126                 }
 127         }
 128         return seen_commits;
 129 }
 130
 131 static void describe(const char *arg, int last_one)
 132 {
 133         unsigned char sha1[20];
 134         struct commit *cmit, *gave_up_on = NULL;
 135         struct commit_list *list;
 136         static int initialized = 0;
 137         struct commit_name *n;
 138         struct possible_tag all_matches[MAX_TAGS];
 139         unsigned int match_cnt = 0, annotated_cnt = 0, cur_match;
 140         unsigned long seen_commits = 0;
 141
 142         if (get_sha1(arg, sha1))
 143                 die("Not a valid object name %s", arg);
 144         cmit = lookup_commit_reference(sha1);
 145         if (!cmit)
 146                 die("%s is not a valid '%s' object", arg, commit_type);
 147
 148         if (!initialized) {
 149                 initialized = 1;
 150                 for_each_ref(get_name, NULL);
 151         }
 152
 153         n = cmit->util;
 154         if (n) {
 155                 printf("%s\n", n->path);
 156                 return;
 157         }
 158
 159         if (debug)
 160                 fprintf(stderr, "searching to describe %s\n", arg);
 161
 162         list = NULL;
 163         cmit->object.flags = SEEN;
 164         commit_list_insert(cmit, &list);
 165         while (list) {
 166                 struct commit *c = pop_commit(&list);
 167                 struct commit_list *parents = c->parents;
 168                 seen_commits++;
 169                 n = c->util;
 170                 if (n) {
 171                         if (match_cnt < max_candidates) {
 172                                 struct possible_tag *t = &all_matches[match_cnt++];
 173                                 t->name = n;
 174                                 t->depth = seen_commits - 1;
 175                                 t->flag_within = 1u << match_cnt;
 176                                 t->found_order = match_cnt;
 177                                 c->object.flags |= t->flag_within;
 178                                 if (n->prio == 2)
 179                                         annotated_cnt++;
 180                         }
 181                         else {
 182                                 gave_up_on = c;
 183                                 break;
 184                         }
 185                 }
 186                 for (cur_match = 0; cur_match < match_cnt; cur_match++) {
 187                         struct possible_tag *t = &all_matches[cur_match];
 188                         if (!(c->object.flags & t->flag_within))
 189                                 t->depth++;
 190                 }
 191                 if (annotated_cnt && !list) {
 192                         if (debug)
 193                                 fprintf(stderr, "finished search at %s\n",
 194                                         sha1_to_hex(c->object.sha1));
 195                         break;
 196                 }
 197                 while (parents) {
 198                         struct commit *p = parents->item;
 199                         parse_commit(p);
 200                         if (!(p->object.flags & SEEN))
 201                                 insert_by_date(p, &list);
 202                         p->object.flags |= c->object.flags;
 203                         parents = parents->next;
 204                 }
 205         }
 206
 207         if (!match_cnt)
 208                 die("cannot describe '%s'", sha1_to_hex(cmit->object.sha1));
 209
 210         qsort(all_matches, match_cnt, sizeof(all_matches[0]), compare_pt);
 211
 212         if (gave_up_on) {
 213                 insert_by_date(gave_up_on, &list);
 214                 seen_commits--;
 215         }
 216         seen_commits += finish_depth_computation(&list, &all_matches[0]);
 217         free_commit_list(list);
 218
 219         if (debug) {
 220                 for (cur_match = 0; cur_match < match_cnt; cur_match++) {
 221                         struct possible_tag *t = &all_matches[cur_match];
 222                         fprintf(stderr, " %-11s %8d %s\n",
 223                                 prio_names[t->name->prio],
 224                                 t->depth, t->name->path);
 225                 }
 226                 fprintf(stderr, "traversed %lu commits\n", seen_commits);
 227                 if (gave_up_on) {
 228                         fprintf(stderr,
 229                                 "more than %i tags found; listed %i most recent\n"
 230                                 "gave up search at %s\n",
 231                                 max_candidates, max_candidates,
 232                                 sha1_to_hex(gave_up_on->object.sha1));
 233                 }
 234         }
 235         if (abbrev == 0)
 236                 printf("%s\n", all_matches[0].name->path );
 237         else
 238                 printf("%s-%d-g%s\n", all_matches[0].name->path,
 239                        all_matches[0].depth,
 240                        find_unique_abbrev(cmit->object.sha1, abbrev));
 241
 242         if (!last_one)
 243                 clear_commit_marks(cmit, -1);
 244 }
 245
 246 int cmd_describe(int argc, const char **argv, const char *prefix)
 247 {
 248         int contains = 0;
 249         struct option options[] = {
 250                 OPT_BOOLEAN(0, "contains",   &contains, "find the tag that comes after the commit"),
 251                 OPT_BOOLEAN(0, "debug",      &debug, "debug search strategy on stderr"),
 252                 OPT_BOOLEAN(0, "all",        &all, "use any ref in .git/refs"),
 253                 OPT_BOOLEAN(0, "tags",       &tags, "use any tag in .git/refs/tags"),
 254                 OPT__ABBREV(&abbrev),
 255                 OPT_INTEGER(0, "candidates", &max_candidates,
 256                                         "consider <n> most recent tags (default: 10)"),
 257                 OPT_END(),
 258         };
 259
 260         argc = parse_options(argc, argv, options, describe_usage, 0);
 261         if (max_candidates < 1)
 262                 max_candidates = 1;
 263         else if (max_candidates > MAX_TAGS)
 264                 max_candidates = MAX_TAGS;
 265
 266         save_commit_buffer = 0;
 267
 268         if (contains) {
 269                 const char **args = xmalloc((4 + argc) * sizeof(char*));
 270                 args[0] = "name-rev";
 271                 args[1] = "--name-only";
 272                 args[2] = "--tags";
 273                 memcpy(args + 3, argv, argc * sizeof(char*));
 274                 args[3 + argc] = NULL;
 275                 return cmd_name_rev(3 + argc, args, prefix);
 276         }
 277
 278         if (argc == 0) {
 279                 describe("HEAD", 1);
 280         } else {
 281                 while (argc-- > 0) {
 282                         describe(*argv++, argc == 0);
 283                 }
 284         }
 285         return 0;
 286 }