diff options
| -rw-r--r-- | Documentation/git-describe.txt | 30 | ||||
| -rw-r--r-- | builtin-describe.c | 125 |
2 files changed, 106 insertions, 49 deletions
diff --git a/Documentation/git-describe.txt b/Documentation/git-describe.txt index 2700f35bd..b87783cf0 100644 --- a/Documentation/git-describe.txt +++ b/Documentation/git-describe.txt @@ -35,6 +35,16 @@ OPTIONS Instead of using the default 8 hexadecimal digits as the abbreviated object name, use <n> digits. +--candidates=<n>:: + Instead of considering only the 10 most recent tags as + candidates to describe the input committish consider + up to <n> candidates. Increasing <n> above 10 will take + slightly longer but may produce a more accurate result. + +--debug:: + Verbosely display information about the searching strategy + being employed to standard error. The tag name will still + be printed to standard out. EXAMPLES -------- @@ -63,6 +73,26 @@ the output shows the reference path as well: [torvalds@g5 git]$ git describe --all HEAD^ heads/lt/describe-g975b +SEARCH STRATEGY +--------------- + +For each committish supplied "git describe" will first look for +a tag which tags exactly that commit. Annotated tags will always +be preferred over lightweight tags, and tags with newer dates will +always be preferred over tags with older dates. If an exact match +is found, its name will be output and searching will stop. + +If an exact match was not found "git describe" will walk back +through the commit history to locate an ancestor commit which +has been tagged. The ancestor's tag will be output along with an +abbreviation of the input committish's SHA1. + +If multiple tags were found during the walk then the tag which +has the fewest commits different from the input committish will be +selected and output. Here fewest commits different is defined as +the number of commits which would be shown by "git log tag..input" +will be the smallest number of commits possible. + Author ------ diff --git a/builtin-describe.c b/builtin-describe.c index 5d6865b16..421658d3b 100644 --- a/builtin-describe.c +++ b/builtin-describe.c @@ -2,17 +2,19 @@ #include "commit.h" #include "tag.h" #include "refs.h" -#include "diff.h" -#include "diffcore.h" -#include "revision.h" #include "builtin.h" +#define SEEN (1u<<0) +#define MAX_TAGS (FLAG_BITS - 1) + static const char describe_usage[] = "git-describe [--all] [--tags] [--abbrev=<n>] <committish>*"; +static int debug; /* Display lots of verbose info */ static int all; /* Default to annotated tags only */ static int tags; /* But allow any tags if --tags is specified */ static int abbrev = DEFAULT_ABBREV; +static int max_candidates = 10; static unsigned int names[256], allocs[256]; static struct commit_name { @@ -115,19 +117,21 @@ static int compare_names(const void *_a, const void *_b) } struct possible_tag { - struct possible_tag *next; struct commit_name *name; unsigned long depth; + unsigned flag_within; }; static void describe(const char *arg, int last_one) { unsigned char sha1[20]; - struct commit *cmit; + struct commit *cmit, *gave_up_on = NULL; struct commit_list *list; static int initialized = 0; struct commit_name *n; - struct possible_tag *all_matches, *min_match, *cur_match; + struct possible_tag all_matches[MAX_TAGS], *min_match; + unsigned int match_cnt = 0, annotated_cnt = 0, cur_match; + unsigned long seen_commits = 0; if (get_sha1(arg, sha1)) die("Not a valid object name %s", arg); @@ -150,71 +154,85 @@ static void describe(const char *arg, int last_one) return; } + if (debug) + fprintf(stderr, "searching to describe %s\n", arg); + list = NULL; - all_matches = NULL; - cur_match = NULL; + cmit->object.flags = SEEN; commit_list_insert(cmit, &list); while (list) { struct commit *c = pop_commit(&list); struct commit_list *parents = c->parents; + seen_commits++; n = match(c); if (n) { - struct possible_tag *p = xmalloc(sizeof(*p)); - p->name = n; - p->next = NULL; - if (cur_match) - cur_match->next = p; - else - all_matches = p; - cur_match = p; - if (n->prio == 2) - continue; + if (match_cnt < max_candidates) { + struct possible_tag *t = &all_matches[match_cnt++]; + t->name = n; + t->depth = seen_commits - 1; + t->flag_within = 1u << match_cnt; + c->object.flags |= t->flag_within; + if (n->prio == 2) + annotated_cnt++; + } + else { + gave_up_on = c; + break; + } + } + for (cur_match = 0; cur_match < match_cnt; cur_match++) { + struct possible_tag *t = &all_matches[cur_match]; + if (!(c->object.flags & t->flag_within)) + t->depth++; + } + if (annotated_cnt && !list) { + if (debug) + fprintf(stderr, "finished search at %s\n", + sha1_to_hex(c->object.sha1)); + break; } while (parents) { struct commit *p = parents->item; parse_commit(p); - if (!(p->object.flags & SEEN)) { - p->object.flags |= SEEN; + if (!(p->object.flags & SEEN)) insert_by_date(p, &list); - } + p->object.flags |= c->object.flags; parents = parents->next; } } + free_commit_list(list); - if (!all_matches) + if (!match_cnt) die("cannot describe '%s'", sha1_to_hex(cmit->object.sha1)); - min_match = NULL; - for (cur_match = all_matches; cur_match; cur_match = cur_match->next) { - struct rev_info revs; - struct commit *tagged = cur_match->name->commit; - - clear_commit_marks(cmit, -1); - init_revisions(&revs, NULL); - tagged->object.flags |= UNINTERESTING; - add_pending_object(&revs, &tagged->object, NULL); - add_pending_object(&revs, &cmit->object, NULL); - - prepare_revision_walk(&revs); - cur_match->depth = 0; - while ((!min_match || cur_match->depth < min_match->depth) - && get_revision(&revs)) - cur_match->depth++; - if (!min_match || (cur_match->depth < min_match->depth - && cur_match->name->prio >= min_match->name->prio)) - min_match = cur_match; - free_commit_list(revs.commits); + min_match = &all_matches[0]; + for (cur_match = 1; cur_match < match_cnt; cur_match++) { + struct possible_tag *t = &all_matches[cur_match]; + if (t->depth < min_match->depth + && t->name->prio >= min_match->name->prio) + min_match = t; + } + if (debug) { + for (cur_match = 0; cur_match < match_cnt; cur_match++) { + struct possible_tag *t = &all_matches[cur_match]; + fprintf(stderr, " %c %8lu %s\n", + min_match == t ? '*' : ' ', + t->depth, t->name->path); + } + fprintf(stderr, "traversed %lu commits\n", seen_commits); + if (gave_up_on) { + fprintf(stderr, + "more than %i tags found; listed %i most recent\n" + "gave up search at %s\n", + max_candidates, max_candidates, + sha1_to_hex(gave_up_on->object.sha1)); + } } printf("%s-g%s\n", min_match->name->path, find_unique_abbrev(cmit->object.sha1, abbrev)); - if (!last_one) { - for (cur_match = all_matches; cur_match; cur_match = min_match) { - min_match = cur_match->next; - free(cur_match); - } - clear_commit_marks(cmit, SEEN); - } + if (!last_one) + clear_commit_marks(cmit, -1); } int cmd_describe(int argc, const char **argv, const char *prefix) @@ -226,6 +244,8 @@ int cmd_describe(int argc, const char **argv, const char *prefix) if (*arg != '-') break; + else if (!strcmp(arg, "--debug")) + debug = 1; else if (!strcmp(arg, "--all")) all = 1; else if (!strcmp(arg, "--tags")) @@ -235,6 +255,13 @@ int cmd_describe(int argc, const char **argv, const char *prefix) if (abbrev < MINIMUM_ABBREV || 40 < abbrev) abbrev = DEFAULT_ABBREV; } + else if (!strncmp(arg, "--candidates=", 13)) { + max_candidates = strtoul(arg + 13, NULL, 10); + if (max_candidates < 1) + max_candidates = 1; + else if (max_candidates > MAX_TAGS) + max_candidates = MAX_TAGS; + } else usage(describe_usage); } |