Make git-describe a builtin.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/builtin-describe.c b/builtin-describe.c
new file mode 100644
index 0000000..ad3b469
--- /dev/null
+++ b/builtin-describe.c
@@ -0,0 +1,176 @@
+#include "cache.h"
+#include "commit.h"
+#include "tag.h"
+#include "refs.h"
+#include "builtin.h"
+
+#define SEEN (1u << 0)
+
+static const char describe_usage[] =
+"git-describe [--all] [--tags] [--abbrev=<n>] <committish>*";
+
+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 names, allocs;
+static struct commit_name {
+ const struct commit *commit;
+ int prio; /* annotated tag = 2, tag = 1, head = 0 */
+ char path[FLEX_ARRAY]; /* more */
+} **name_array = NULL;
+
+static struct commit_name *match(struct commit *cmit)
+{
+ int i = names;
+ struct commit_name **p = name_array;
+
+ while (i-- > 0) {
+ struct commit_name *n = *p++;
+ if (n->commit == cmit)
+ return n;
+ }
+ return NULL;
+}
+
+static void add_to_known_names(const char *path,
+ const struct commit *commit,
+ int prio)
+{
+ int idx;
+ int len = strlen(path)+1;
+ struct commit_name *name = xmalloc(sizeof(struct commit_name) + len);
+
+ name->commit = commit;
+ name->prio = prio;
+ memcpy(name->path, path, len);
+ idx = names;
+ if (idx >= allocs) {
+ allocs = (idx + 50) * 3 / 2;
+ name_array = xrealloc(name_array, allocs*sizeof(*name_array));
+ }
+ name_array[idx] = name;
+ names = ++idx;
+}
+
+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 (!strncmp(path, "refs/tags/", 10)) {
+ 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;
+}
+
+static int compare_names(const void *_a, const void *_b)
+{
+ struct commit_name *a = *(struct commit_name **)_a;
+ struct commit_name *b = *(struct commit_name **)_b;
+ unsigned long a_date = a->commit->date;
+ unsigned long b_date = b->commit->date;
+
+ if (a->prio != b->prio)
+ return b->prio - a->prio;
+ return (a_date > b_date) ? -1 : (a_date == b_date) ? 0 : 1;
+}
+
+static void describe(const char *arg, int last_one)
+{
+ unsigned char sha1[20];
+ struct commit *cmit;
+ struct commit_list *list;
+ static int initialized = 0;
+ struct commit_name *n;
+
+ 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);
+ qsort(name_array, names, sizeof(*name_array), compare_names);
+ }
+
+ n = match(cmit);
+ if (n) {
+ printf("%s\n", n->path);
+ return;
+ }
+
+ list = NULL;
+ commit_list_insert(cmit, &list);
+ while (list) {
+ struct commit *c = pop_most_recent_commit(&list, SEEN);
+ n = match(c);
+ if (n) {
+ printf("%s-g%s\n", n->path,
+ find_unique_abbrev(cmit->object.sha1, abbrev));
+ if (!last_one)
+ clear_commit_marks(cmit, SEEN);
+ return;
+ }
+ }
+ die("cannot describe '%s'", sha1_to_hex(cmit->object.sha1));
+}
+
+int cmd_describe(int argc, const char **argv, const char *prefix)
+{
+ int i;
+
+ for (i = 1; i < argc; i++) {
+ const char *arg = argv[i];
+
+ if (*arg != '-')
+ break;
+ else if (!strcmp(arg, "--all"))
+ all = 1;
+ else if (!strcmp(arg, "--tags"))
+ tags = 1;
+ else if (!strncmp(arg, "--abbrev=", 9)) {
+ abbrev = strtoul(arg + 9, NULL, 10);
+ if (abbrev < MINIMUM_ABBREV || 40 < abbrev)
+ abbrev = DEFAULT_ABBREV;
+ }
+ else
+ usage(describe_usage);
+ }
+
+ save_commit_buffer = 0;
+
+ if (argc <= i)
+ describe("HEAD", 1);
+ else
+ while (i < argc) {
+ describe(argv[i], (i == argc - 1));
+ i++;
+ }
+
+ return 0;
+}
