Andrew's git - gitweb.git/blob - 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
  12static const char * const describe_usage[] = {
  13        "git-describe [options] <committish>*",
  14        NULL
  15};
  16
  17static int debug;       /* Display lots of verbose info */
  18static int all; /* Default to annotated tags only */
  19static int tags;        /* But allow any tags if --tags is specified */
  20static int abbrev = DEFAULT_ABBREV;
  21static int max_candidates = 10;
  22
  23struct commit_name {
  24        int prio; /* annotated tag = 2, tag = 1, head = 0 */
  25        char path[FLEX_ARRAY]; /* more */
  26};
  27static const char *prio_names[] = {
  28        "head", "lightweight", "annotated",
  29};
  30
  31static 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
  46static 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
  78struct possible_tag {
  79        struct commit_name *name;
  80        int depth;
  81        int found_order;
  82        unsigned flag_within;
  83};
  84
  85static 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
  98static 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
 131static 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
 246int 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                int i = 0;
 271                args[i++] = "name-rev";
 272                args[i++] = "--name-only";
 273                if (!all)
 274                        args[i++] = "--tags";
 275                memcpy(args + i, argv, argc * sizeof(char*));
 276                args[i + argc] = NULL;
 277                return cmd_name_rev(i + argc, args, prefix);
 278        }
 279
 280        if (argc == 0) {
 281                describe("HEAD", 1);
 282        } else {
 283                while (argc-- > 0) {
 284                        describe(*argv++, argc == 0);
 285                }
 286        }
 287        return 0;
 288}