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-rw-r--r--builtin-describe.c288
1 files changed, 288 insertions, 0 deletions
diff --git a/builtin-describe.c b/builtin-describe.c
new file mode 100644
index 0000000..7a148a2
--- /dev/null
+++ b/builtin-describe.c
@@ -0,0 +1,288 @@
+#include "cache.h"
+#include "commit.h"
+#include "tag.h"
+#include "refs.h"
+#include "builtin.h"
+#include "exec_cmd.h"
+#include "parse-options.h"
+
+#define SEEN (1u<<0)
+#define MAX_TAGS (FLAG_BITS - 1)
+
+static const char * const describe_usage[] = {
+ "git-describe [options] <committish>*",
+ NULL
+};
+
+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;
+
+struct commit_name {
+ int prio; /* annotated tag = 2, tag = 1, head = 0 */
+ char path[FLEX_ARRAY]; /* more */
+};
+static const char *prio_names[] = {
+ "head", "lightweight", "annotated",
+};
+
+static void add_to_known_names(const char *path,
+ struct commit *commit,
+ int prio)
+{
+ struct commit_name *e = commit->util;
+ if (!e || e->prio < prio) {
+ size_t len = strlen(path)+1;
+ free(e);
+ e = xmalloc(sizeof(struct commit_name) + len);
+ e->prio = prio;
+ memcpy(e->path, path, len);
+ commit->util = e;
+ }
+}
+
+static int get_name(const char *path, const unsigned char *sha1, int flag, void *cb_data)
+{
+ struct commit *commit = lookup_commit_reference_gently(sha1, 1);
+ struct object *object;
+ int prio;
+
+ if (!commit)
+ return 0;
+ object = parse_object(sha1);
+ /* If --all, then any refs are used.
+ * If --tags, then any tags are used.
+ * Otherwise only annotated tags are used.
+ */
+ if (!prefixcmp(path, "refs/tags/")) {
+ if (object->type == OBJ_TAG)
+ prio = 2;
+ else
+ prio = 1;
+ }
+ else
+ prio = 0;
+
+ if (!all) {
+ if (!prio)
+ return 0;
+ if (!tags && prio < 2)
+ return 0;
+ }
+ add_to_known_names(all ? path + 5 : path + 10, commit, prio);
+ return 0;
+}
+
+struct possible_tag {
+ struct commit_name *name;
+ int depth;
+ int found_order;
+ unsigned flag_within;
+};
+
+static int compare_pt(const void *a_, const void *b_)
+{
+ struct possible_tag *a = (struct possible_tag *)a_;
+ struct possible_tag *b = (struct possible_tag *)b_;
+ if (a->name->prio != b->name->prio)
+ return b->name->prio - a->name->prio;
+ if (a->depth != b->depth)
+ return a->depth - b->depth;
+ if (a->found_order != b->found_order)
+ return a->found_order - b->found_order;
+ return 0;
+}
+
+static unsigned long finish_depth_computation(
+ struct commit_list **list,
+ struct possible_tag *best)
+{
+ unsigned long seen_commits = 0;
+ while (*list) {
+ struct commit *c = pop_commit(list);
+ struct commit_list *parents = c->parents;
+ seen_commits++;
+ if (c->object.flags & best->flag_within) {
+ struct commit_list *a = *list;
+ while (a) {
+ struct commit *i = a->item;
+ if (!(i->object.flags & best->flag_within))
+ break;
+ a = a->next;
+ }
+ if (!a)
+ break;
+ } else
+ best->depth++;
+ while (parents) {
+ struct commit *p = parents->item;
+ parse_commit(p);
+ if (!(p->object.flags & SEEN))
+ insert_by_date(p, list);
+ p->object.flags |= c->object.flags;
+ parents = parents->next;
+ }
+ }
+ return seen_commits;
+}
+
+static void describe(const char *arg, int last_one)
+{
+ unsigned char sha1[20];
+ struct commit *cmit, *gave_up_on = NULL;
+ struct commit_list *list;
+ static int initialized = 0;
+ struct commit_name *n;
+ struct possible_tag all_matches[MAX_TAGS];
+ 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);
+ cmit = lookup_commit_reference(sha1);
+ if (!cmit)
+ die("%s is not a valid '%s' object", arg, commit_type);
+
+ if (!initialized) {
+ initialized = 1;
+ for_each_ref(get_name, NULL);
+ }
+
+ n = cmit->util;
+ if (n) {
+ printf("%s\n", n->path);
+ return;
+ }
+
+ if (debug)
+ fprintf(stderr, "searching to describe %s\n", arg);
+
+ list = 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 = c->util;
+ if (n) {
+ 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;
+ t->found_order = 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))
+ insert_by_date(p, &list);
+ p->object.flags |= c->object.flags;
+ parents = parents->next;
+ }
+ }
+
+ if (!match_cnt)
+ die("cannot describe '%s'", sha1_to_hex(cmit->object.sha1));
+
+ qsort(all_matches, match_cnt, sizeof(all_matches[0]), compare_pt);
+
+ if (gave_up_on) {
+ insert_by_date(gave_up_on, &list);
+ seen_commits--;
+ }
+ seen_commits += finish_depth_computation(&list, &all_matches[0]);
+ free_commit_list(list);
+
+ if (debug) {
+ for (cur_match = 0; cur_match < match_cnt; cur_match++) {
+ struct possible_tag *t = &all_matches[cur_match];
+ fprintf(stderr, " %-11s %8d %s\n",
+ prio_names[t->name->prio],
+ 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));
+ }
+ }
+ if (abbrev == 0)
+ printf("%s\n", all_matches[0].name->path );
+ else
+ printf("%s-%d-g%s\n", all_matches[0].name->path,
+ all_matches[0].depth,
+ find_unique_abbrev(cmit->object.sha1, abbrev));
+
+ if (!last_one)
+ clear_commit_marks(cmit, -1);
+}
+
+int cmd_describe(int argc, const char **argv, const char *prefix)
+{
+ int contains = 0;
+ struct option options[] = {
+ OPT_BOOLEAN(0, "contains", &contains, "find the tag that comes after the commit"),
+ OPT_BOOLEAN(0, "debug", &debug, "debug search strategy on stderr"),
+ OPT_BOOLEAN(0, "all", &all, "use any ref in .git/refs"),
+ OPT_BOOLEAN(0, "tags", &tags, "use any tag in .git/refs/tags"),
+ OPT__ABBREV(&abbrev),
+ OPT_INTEGER(0, "candidates", &max_candidates,
+ "consider <n> most recent tags (default: 10)"),
+ OPT_END(),
+ };
+
+ argc = parse_options(argc, argv, options, describe_usage, 0);
+ if (max_candidates < 1)
+ max_candidates = 1;
+ else if (max_candidates > MAX_TAGS)
+ max_candidates = MAX_TAGS;
+
+ save_commit_buffer = 0;
+
+ if (contains) {
+ const char **args = xmalloc((4 + argc) * sizeof(char*));
+ int i = 0;
+ args[i++] = "name-rev";
+ args[i++] = "--name-only";
+ if (!all)
+ args[i++] = "--tags";
+ memcpy(args + i, argv, argc * sizeof(char*));
+ args[i + argc] = NULL;
+ return cmd_name_rev(i + argc, args, prefix);
+ }
+
+ if (argc == 0) {
+ describe("HEAD", 1);
+ } else {
+ while (argc-- > 0) {
+ describe(*argv++, argc == 0);
+ }
+ }
+ return 0;
+}