builtin-describe.c - pub/scm/git/git - Git at Google

 #include "cache.h"
 #include "commit.h"
 #include "tag.h"
 #include "refs.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;

 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 (!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;
 }

 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 i;

 	for (i = 1; i < argc; i++) {
 		const char *arg = argv[i];

 		if (*arg != '-')
 			break;
 		else if (!strcmp(arg, "--debug"))
 			debug = 1;
 		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 != 0 && (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);
 	}

 	save_commit_buffer = 0;

 	if (argc <= i)
 		describe("HEAD", 1);
 	else
 		while (i < argc) {
 			describe(argv[i], (i == argc - 1));
 			i++;
 		}

 	return 0;
 }
	#include "cache.h"
	#include "commit.h"
	#include "tag.h"
	#include "refs.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;

	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 (!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;
	}

	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 i;

	for (i = 1; i < argc; i++) {
	const char *arg = argv[i];

	if (*arg != '-')
	break;
	else if (!strcmp(arg, "--debug"))
	debug = 1;
	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 != 0 && (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);
	}

	save_commit_buffer = 0;

	if (argc <= i)
	describe("HEAD", 1);
	else
	while (i < argc) {
	describe(argv[i], (i == argc - 1));
	i++;
	}

	return 0;
	}