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
--------
[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
------
#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 {
}
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);
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)
if (*arg != '-')
break;
+ else if (!strcmp(arg, "--debug"))
+ debug = 1;
else if (!strcmp(arg, "--all"))
all = 1;
else if (!strcmp(arg, "--tags"))
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);
}