1 files changed, 662 insertions, 0 deletions

diff --git a/builtin/describe.c b/builtin/describe.c
new file mode 100644
index 000000000000..200154297d5e
--- /dev/null
+++ b/builtin/describe.c
@@ -0,0 +1,662 @@
+#define USE_THE_INDEX_COMPATIBILITY_MACROS
+#include "cache.h"
+#include "config.h"
+#include "lockfile.h"
+#include "commit.h"
+#include "tag.h"
+#include "blob.h"
+#include "refs.h"
+#include "builtin.h"
+#include "exec-cmd.h"
+#include "parse-options.h"
+#include "revision.h"
+#include "diff.h"
+#include "hashmap.h"
+#include "argv-array.h"
+#include "run-command.h"
+#include "object-store.h"
+#include "revision.h"
+#include "list-objects.h"
+#include "commit-slab.h"
+
+#define MAX_TAGS	(FLAG_BITS - 1)
+
+define_commit_slab(commit_names, struct commit_name *);
+
+static const char * const describe_usage[] = {
+	N_("git describe [<options>] [<commit-ish>...]"),
+	N_("git describe [<options>] --dirty"),
+	NULL
+};
+
+static int debug;	/* Display lots of verbose info */
+static int all;	/* Any valid ref can be used */
+static int tags;	/* Allow lightweight tags */
+static int longformat;
+static int first_parent;
+static int abbrev = -1; /* unspecified */
+static int max_candidates = 10;
+static struct hashmap names;
+static int have_util;
+static struct string_list patterns = STRING_LIST_INIT_NODUP;
+static struct string_list exclude_patterns = STRING_LIST_INIT_NODUP;
+static int always;
+static const char *suffix, *dirty, *broken;
+static struct commit_names commit_names;
+
+/* diff-index command arguments to check if working tree is dirty. */
+static const char *diff_index_args[] = {
+	"diff-index", "--quiet", "HEAD", "--", NULL
+};
+
+struct commit_name {
+	struct hashmap_entry entry;
+	struct object_id peeled;
+	struct tag *tag;
+	unsigned prio:2; /* annotated tag = 2, tag = 1, head = 0 */
+	unsigned name_checked:1;
+	struct object_id oid;
+	char *path;
+};
+
+static const char *prio_names[] = {
+	N_("head"), N_("lightweight"), N_("annotated"),
+};
+
+static int commit_name_neq(const void *unused_cmp_data,
+			   const void *entry,
+			   const void *entry_or_key,
+			   const void *peeled)
+{
+	const struct commit_name *cn1 = entry;
+	const struct commit_name *cn2 = entry_or_key;
+
+	return !oideq(&cn1->peeled, peeled ? peeled : &cn2->peeled);
+}
+
+static inline struct commit_name *find_commit_name(const struct object_id *peeled)
+{
+	return hashmap_get_from_hash(&names, oidhash(peeled), peeled);
+}
+
+static int replace_name(struct commit_name *e,
+			       int prio,
+			       const struct object_id *oid,
+			       struct tag **tag)
+{
+	if (!e || e->prio < prio)
+		return 1;
+
+	if (e->prio == 2 && prio == 2) {
+		/* Multiple annotated tags point to the same commit.
+		 * Select one to keep based upon their tagger date.
+		 */
+		struct tag *t;
+
+		if (!e->tag) {
+			t = lookup_tag(the_repository, &e->oid);
+			if (!t || parse_tag(t))
+				return 1;
+			e->tag = t;
+		}
+
+		t = lookup_tag(the_repository, oid);
+		if (!t || parse_tag(t))
+			return 0;
+		*tag = t;
+
+		if (e->tag->date < t->date)
+			return 1;
+	}
+
+	return 0;
+}
+
+static void add_to_known_names(const char *path,
+			       const struct object_id *peeled,
+			       int prio,
+			       const struct object_id *oid)
+{
+	struct commit_name *e = find_commit_name(peeled);
+	struct tag *tag = NULL;
+	if (replace_name(e, prio, oid, &tag)) {
+		if (!e) {
+			e = xmalloc(sizeof(struct commit_name));
+			oidcpy(&e->peeled, peeled);
+			hashmap_entry_init(e, oidhash(peeled));
+			hashmap_add(&names, e);
+			e->path = NULL;
+		}
+		e->tag = tag;
+		e->prio = prio;
+		e->name_checked = 0;
+		oidcpy(&e->oid, oid);
+		free(e->path);
+		e->path = xstrdup(path);
+	}
+}
+
+static int get_name(const char *path, const struct object_id *oid, int flag, void *cb_data)
+{
+	int is_tag = 0;
+	struct object_id peeled;
+	int is_annotated, prio;
+	const char *path_to_match = NULL;
+
+	if (skip_prefix(path, "refs/tags/", &path_to_match)) {
+		is_tag = 1;
+	} else if (all) {
+		if ((exclude_patterns.nr || patterns.nr) &&
+		    !skip_prefix(path, "refs/heads/", &path_to_match) &&
+		    !skip_prefix(path, "refs/remotes/", &path_to_match)) {
+			/* Only accept reference of known type if there are match/exclude patterns */
+			return 0;
+		}
+	} else {
+		/* Reject anything outside refs/tags/ unless --all */
+		return 0;
+	}
+
+	/*
+	 * If we're given exclude patterns, first exclude any tag which match
+	 * any of the exclude pattern.
+	 */
+	if (exclude_patterns.nr) {
+		struct string_list_item *item;
+
+		for_each_string_list_item(item, &exclude_patterns) {
+			if (!wildmatch(item->string, path_to_match, 0))
+				return 0;
+		}
+	}
+
+	/*
+	 * If we're given patterns, accept only tags which match at least one
+	 * pattern.
+	 */
+	if (patterns.nr) {
+		int found = 0;
+		struct string_list_item *item;
+
+		for_each_string_list_item(item, &patterns) {
+			if (!wildmatch(item->string, path_to_match, 0)) {
+				found = 1;
+				break;
+			}
+		}
+
+		if (!found)
+			return 0;
+	}
+
+	/* Is it annotated? */
+	if (!peel_ref(path, &peeled)) {
+		is_annotated = !oideq(oid, &peeled);
+	} else {
+		oidcpy(&peeled, oid);
+		is_annotated = 0;
+	}
+
+	/*
+	 * By default, we only use annotated tags, but with --tags
+	 * we fall back to lightweight ones (even without --tags,
+	 * we still remember lightweight ones, only to give hints
+	 * in an error message).  --all allows any refs to be used.
+	 */
+	if (is_annotated)
+		prio = 2;
+	else if (is_tag)
+		prio = 1;
+	else
+		prio = 0;
+
+	add_to_known_names(all ? path + 5 : path + 10, &peeled, prio, oid);
+	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->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))
+				commit_list_insert_by_date(p, list);
+			p->object.flags |= c->object.flags;
+			parents = parents->next;
+		}
+	}
+	return seen_commits;
+}
+
+static void append_name(struct commit_name *n, struct strbuf *dst)
+{
+	if (n->prio == 2 && !n->tag) {
+		n->tag = lookup_tag(the_repository, &n->oid);
+		if (!n->tag || parse_tag(n->tag))
+			die(_("annotated tag %s not available"), n->path);
+	}
+	if (n->tag && !n->name_checked) {
+		if (!n->tag->tag)
+			die(_("annotated tag %s has no embedded name"), n->path);
+		if (strcmp(n->tag->tag, all ? n->path + 5 : n->path))
+			warning(_("tag '%s' is really '%s' here"), n->tag->tag, n->path);
+		n->name_checked = 1;
+	}
+
+	if (n->tag) {
+		if (all)
+			strbuf_addstr(dst, "tags/");
+		strbuf_addstr(dst, n->tag->tag);
+	} else {
+		strbuf_addstr(dst, n->path);
+	}
+}
+
+static void append_suffix(int depth, const struct object_id *oid, struct strbuf *dst)
+{
+	strbuf_addf(dst, "-%d-g%s", depth, find_unique_abbrev(oid, abbrev));
+}
+
+static void describe_commit(struct object_id *oid, struct strbuf *dst)
+{
+	struct commit *cmit, *gave_up_on = NULL;
+	struct commit_list *list;
+	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;
+	unsigned int unannotated_cnt = 0;
+
+	cmit = lookup_commit_reference(the_repository, oid);
+
+	n = find_commit_name(&cmit->object.oid);
+	if (n && (tags || all || n->prio == 2)) {
+		/*
+		 * Exact match to an existing ref.
+		 */
+		append_name(n, dst);
+		if (longformat)
+			append_suffix(0, n->tag ? &n->tag->tagged->oid : oid, dst);
+		if (suffix)
+			strbuf_addstr(dst, suffix);
+		return;
+	}
+
+	if (!max_candidates)
+		die(_("no tag exactly matches '%s'"), oid_to_hex(&cmit->object.oid));
+	if (debug)
+		fprintf(stderr, _("No exact match on refs or tags, searching to describe\n"));
+
+	if (!have_util) {
+		struct hashmap_iter iter;
+		struct commit *c;
+		struct commit_name *n;
+
+		init_commit_names(&commit_names);
+		n = hashmap_iter_first(&names, &iter);
+		for (; n; n = hashmap_iter_next(&iter)) {
+			c = lookup_commit_reference_gently(the_repository,
+							   &n->peeled, 1);
+			if (c)
+				*commit_names_at(&commit_names, c) = n;
+		}
+		have_util = 1;
+	}
+
+	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;
+		struct commit_name **slot;
+
+		seen_commits++;
+		slot = commit_names_peek(&commit_names, c);
+		n = slot ? *slot : NULL;
+		if (n) {
+			if (!tags && !all && n->prio < 2) {
+				unannotated_cnt++;
+			} else 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"),
+					oid_to_hex(&c->object.oid));
+			break;
+		}
+		while (parents) {
+			struct commit *p = parents->item;
+			parse_commit(p);
+			if (!(p->object.flags & SEEN))
+				commit_list_insert_by_date(p, &list);
+			p->object.flags |= c->object.flags;
+			parents = parents->next;
+
+			if (first_parent)
+				break;
+		}
+	}
+
+	if (!match_cnt) {
+		struct object_id *cmit_oid = &cmit->object.oid;
+		if (always) {
+			strbuf_add_unique_abbrev(dst, cmit_oid, abbrev);
+			if (suffix)
+				strbuf_addstr(dst, suffix);
+			return;
+		}
+		if (unannotated_cnt)
+			die(_("No annotated tags can describe '%s'.\n"
+			    "However, there were unannotated tags: try --tags."),
+			    oid_to_hex(cmit_oid));
+		else
+			die(_("No tags can describe '%s'.\n"
+			    "Try --always, or create some tags."),
+			    oid_to_hex(cmit_oid));
+	}
+
+	QSORT(all_matches, match_cnt, compare_pt);
+
+	if (gave_up_on) {
+		commit_list_insert_by_date(gave_up_on, &list);
+		seen_commits--;
+	}
+	seen_commits += finish_depth_computation(&list, &all_matches[0]);
+	free_commit_list(list);
+
+	if (debug) {
+		static int label_width = -1;
+		if (label_width < 0) {
+			int i, w;
+			for (i = 0; i < ARRAY_SIZE(prio_names); i++) {
+				w = strlen(_(prio_names[i]));
+				if (label_width < w)
+					label_width = w;
+			}
+		}
+		for (cur_match = 0; cur_match < match_cnt; cur_match++) {
+			struct possible_tag *t = &all_matches[cur_match];
+			fprintf(stderr, " %-*s %8d %s\n",
+				label_width, _(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,
+				oid_to_hex(&gave_up_on->object.oid));
+		}
+	}
+
+	append_name(all_matches[0].name, dst);
+	if (abbrev)
+		append_suffix(all_matches[0].depth, &cmit->object.oid, dst);
+	if (suffix)
+		strbuf_addstr(dst, suffix);
+}
+
+struct process_commit_data {
+	struct object_id current_commit;
+	struct object_id looking_for;
+	struct strbuf *dst;
+	struct rev_info *revs;
+};
+
+static void process_commit(struct commit *commit, void *data)
+{
+	struct process_commit_data *pcd = data;
+	pcd->current_commit = commit->object.oid;
+}
+
+static void process_object(struct object *obj, const char *path, void *data)
+{
+	struct process_commit_data *pcd = data;
+
+	if (oideq(&pcd->looking_for, &obj->oid) && !pcd->dst->len) {
+		reset_revision_walk();
+		describe_commit(&pcd->current_commit, pcd->dst);
+		strbuf_addf(pcd->dst, ":%s", path);
+		free_commit_list(pcd->revs->commits);
+		pcd->revs->commits = NULL;
+	}
+}
+
+static void describe_blob(struct object_id oid, struct strbuf *dst)
+{
+	struct rev_info revs;
+	struct argv_array args = ARGV_ARRAY_INIT;
+	struct process_commit_data pcd = { null_oid, oid, dst, &revs};
+
+	argv_array_pushl(&args, "internal: The first arg is not parsed",
+		"--objects", "--in-commit-order", "--reverse", "HEAD",
+		NULL);
+
+	repo_init_revisions(the_repository, &revs, NULL);
+	if (setup_revisions(args.argc, args.argv, &revs, NULL) > 1)
+		BUG("setup_revisions could not handle all args?");
+
+	if (prepare_revision_walk(&revs))
+		die("revision walk setup failed");
+
+	traverse_commit_list(&revs, process_commit, process_object, &pcd);
+	reset_revision_walk();
+}
+
+static void describe(const char *arg, int last_one)
+{
+	struct object_id oid;
+	struct commit *cmit;
+	struct strbuf sb = STRBUF_INIT;
+
+	if (debug)
+		fprintf(stderr, _("describe %s\n"), arg);
+
+	if (get_oid(arg, &oid))
+		die(_("Not a valid object name %s"), arg);
+	cmit = lookup_commit_reference_gently(the_repository, &oid, 1);
+
+	if (cmit)
+		describe_commit(&oid, &sb);
+	else if (oid_object_info(the_repository, &oid, NULL) == OBJ_BLOB)
+		describe_blob(oid, &sb);
+	else
+		die(_("%s is neither a commit nor blob"), arg);
+
+	puts(sb.buf);
+
+	if (!last_one)
+		clear_commit_marks(cmit, -1);
+
+	strbuf_release(&sb);
+}
+
+int cmd_describe(int argc, const char **argv, const char *prefix)
+{
+	int contains = 0;
+	struct option options[] = {
+		OPT_BOOL(0, "contains",   &contains, N_("find the tag that comes after the commit")),
+		OPT_BOOL(0, "debug",      &debug, N_("debug search strategy on stderr")),
+		OPT_BOOL(0, "all",        &all, N_("use any ref")),
+		OPT_BOOL(0, "tags",       &tags, N_("use any tag, even unannotated")),
+		OPT_BOOL(0, "long",       &longformat, N_("always use long format")),
+		OPT_BOOL(0, "first-parent", &first_parent, N_("only follow first parent")),
+		OPT__ABBREV(&abbrev),
+		OPT_SET_INT(0, "exact-match", &max_candidates,
+			    N_("only output exact matches"), 0),
+		OPT_INTEGER(0, "candidates", &max_candidates,
+			    N_("consider <n> most recent tags (default: 10)")),
+		OPT_STRING_LIST(0, "match", &patterns, N_("pattern"),
+			   N_("only consider tags matching <pattern>")),
+		OPT_STRING_LIST(0, "exclude", &exclude_patterns, N_("pattern"),
+			   N_("do not consider tags matching <pattern>")),
+		OPT_BOOL(0, "always",        &always,
+			N_("show abbreviated commit object as fallback")),
+		{OPTION_STRING, 0, "dirty",  &dirty, N_("mark"),
+			N_("append <mark> on dirty working tree (default: \"-dirty\")"),
+			PARSE_OPT_OPTARG, NULL, (intptr_t) "-dirty"},
+		{OPTION_STRING, 0, "broken",  &broken, N_("mark"),
+			N_("append <mark> on broken working tree (default: \"-broken\")"),
+			PARSE_OPT_OPTARG, NULL, (intptr_t) "-broken"},
+		OPT_END(),
+	};
+
+	git_config(git_default_config, NULL);
+	argc = parse_options(argc, argv, prefix, options, describe_usage, 0);
+	if (abbrev < 0)
+		abbrev = DEFAULT_ABBREV;
+
+	if (max_candidates < 0)
+		max_candidates = 0;
+	else if (max_candidates > MAX_TAGS)
+		max_candidates = MAX_TAGS;
+
+	save_commit_buffer = 0;
+
+	if (longformat && abbrev == 0)
+		die(_("--long is incompatible with --abbrev=0"));
+
+	if (contains) {
+		struct string_list_item *item;
+		struct argv_array args;
+
+		argv_array_init(&args);
+		argv_array_pushl(&args, "name-rev",
+				 "--peel-tag", "--name-only", "--no-undefined",
+				 NULL);
+		if (always)
+			argv_array_push(&args, "--always");
+		if (!all) {
+			argv_array_push(&args, "--tags");
+			for_each_string_list_item(item, &patterns)
+				argv_array_pushf(&args, "--refs=refs/tags/%s", item->string);
+			for_each_string_list_item(item, &exclude_patterns)
+				argv_array_pushf(&args, "--exclude=refs/tags/%s", item->string);
+		}
+		if (argc)
+			argv_array_pushv(&args, argv);
+		else
+			argv_array_push(&args, "HEAD");
+		return cmd_name_rev(args.argc, args.argv, prefix);
+	}
+
+	hashmap_init(&names, commit_name_neq, NULL, 0);
+	for_each_rawref(get_name, NULL);
+	if (!hashmap_get_size(&names) && !always)
+		die(_("No names found, cannot describe anything."));
+
+	if (argc == 0) {
+		if (broken) {
+			struct child_process cp = CHILD_PROCESS_INIT;
+			argv_array_pushv(&cp.args, diff_index_args);
+			cp.git_cmd = 1;
+			cp.no_stdin = 1;
+			cp.no_stdout = 1;
+
+			if (!dirty)
+				dirty = "-dirty";
+
+			switch (run_command(&cp)) {
+			case 0:
+				suffix = NULL;
+				break;
+			case 1:
+				suffix = dirty;
+				break;
+			default:
+				/* diff-index aborted abnormally */
+				suffix = broken;
+			}
+		} else if (dirty) {
+			struct lock_file index_lock = LOCK_INIT;
+			struct rev_info revs;
+			struct argv_array args = ARGV_ARRAY_INIT;
+			int fd, result;
+
+			setup_work_tree();
+			read_cache();
+			refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED,
+				      NULL, NULL, NULL);
+			fd = hold_locked_index(&index_lock, 0);
+			if (0 <= fd)
+				repo_update_index_if_able(the_repository, &index_lock);
+
+			repo_init_revisions(the_repository, &revs, prefix);
+			argv_array_pushv(&args, diff_index_args);
+			if (setup_revisions(args.argc, args.argv, &revs, NULL) != 1)
+				BUG("malformed internal diff-index command line");
+			result = run_diff_index(&revs, 0);
+
+			if (!diff_result_code(&revs.diffopt, result))
+				suffix = NULL;
+			else
+				suffix = dirty;
+		}
+		describe("HEAD", 1);
+	} else if (dirty) {
+		die(_("--dirty is incompatible with commit-ishes"));
+	} else if (broken) {
+		die(_("--broken is incompatible with commit-ishes"));
+	} else {
+		while (argc-- > 0)
+			describe(*argv++, argc == 0);
+	}
+	return 0;
+}