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

 /*
  * git gc builtin command
  *
  * Cleanup unreachable files and optimize the repository.
  *
  * Copyright (c) 2007 James Bowes
  *
  * Based on git-gc.sh, which is
  *
  * Copyright (c) 2006 Shawn O. Pearce
  */

 #include "builtin.h"
 #include "tempfile.h"
 #include "lockfile.h"
 #include "parse-options.h"
 #include "run-command.h"
 #include "sigchain.h"
 #include "argv-array.h"
 #include "commit.h"

 #define FAILED_RUN "failed to run %s"

 static const char * const builtin_gc_usage[] = {
 	N_("git gc [<options>]"),
 	NULL
 };

 static int pack_refs = 1;
 static int prune_reflogs = 1;
 static int aggressive_depth = 250;
 static int aggressive_window = 250;
 static int gc_auto_threshold = 6700;
 static int gc_auto_pack_limit = 50;
 static int detach_auto = 1;
 static const char *prune_expire = "2.weeks.ago";
 static const char *prune_worktrees_expire = "3.months.ago";

 static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT;
 static struct argv_array reflog = ARGV_ARRAY_INIT;
 static struct argv_array repack = ARGV_ARRAY_INIT;
 static struct argv_array prune = ARGV_ARRAY_INIT;
 static struct argv_array prune_worktrees = ARGV_ARRAY_INIT;
 static struct argv_array rerere = ARGV_ARRAY_INIT;

 static struct tempfile pidfile;

 static void git_config_date_string(const char *key, const char **output)
 {
 	if (git_config_get_string_const(key, output))
 		return;
 	if (strcmp(*output, "now")) {
 		unsigned long now = approxidate("now");
 		if (approxidate(*output) >= now)
 			git_die_config(key, _("Invalid %s: '%s'"), key, *output);
 	}
 }

 static void gc_config(void)
 {
 	const char *value;

 	if (!git_config_get_value("gc.packrefs", &value)) {
 		if (value && !strcmp(value, "notbare"))
 			pack_refs = -1;
 		else
 			pack_refs = git_config_bool("gc.packrefs", value);
 	}

 	git_config_get_int("gc.aggressivewindow", &aggressive_window);
 	git_config_get_int("gc.aggressivedepth", &aggressive_depth);
 	git_config_get_int("gc.auto", &gc_auto_threshold);
 	git_config_get_int("gc.autopacklimit", &gc_auto_pack_limit);
 	git_config_get_bool("gc.autodetach", &detach_auto);
 	git_config_date_string("gc.pruneexpire", &prune_expire);
 	git_config_date_string("gc.worktreepruneexpire", &prune_worktrees_expire);
 	git_config(git_default_config, NULL);
 }

 static int too_many_loose_objects(void)
 {
 	/*
 	 * Quickly check if a "gc" is needed, by estimating how
 	 * many loose objects there are.  Because SHA-1 is evenly
 	 * distributed, we can check only one and get a reasonable
 	 * estimate.
 	 */
 	char path[PATH_MAX];
 	const char *objdir = get_object_directory();
 	DIR *dir;
 	struct dirent *ent;
 	int auto_threshold;
 	int num_loose = 0;
 	int needed = 0;

 	if (gc_auto_threshold <= 0)
 		return 0;

 	if (sizeof(path) <= snprintf(path, sizeof(path), "%s/17", objdir)) {
 		warning(_("insanely long object directory %.*s"), 50, objdir);
 		return 0;
 	}
 	dir = opendir(path);
 	if (!dir)
 		return 0;

 	auto_threshold = (gc_auto_threshold + 255) / 256;
 	while ((ent = readdir(dir)) != NULL) {
 		if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
 		    ent->d_name[38] != '\0')
 			continue;
 		if (++num_loose > auto_threshold) {
 			needed = 1;
 			break;
 		}
 	}
 	closedir(dir);
 	return needed;
 }

 static int too_many_packs(void)
 {
 	struct packed_git *p;
 	int cnt;

 	if (gc_auto_pack_limit <= 0)
 		return 0;

 	prepare_packed_git();
 	for (cnt = 0, p = packed_git; p; p = p->next) {
 		if (!p->pack_local)
 			continue;
 		if (p->pack_keep)
 			continue;
 		/*
 		 * Perhaps check the size of the pack and count only
 		 * very small ones here?
 		 */
 		cnt++;
 	}
 	return gc_auto_pack_limit <= cnt;
 }

 static void add_repack_all_option(void)
 {
 	if (prune_expire && !strcmp(prune_expire, "now"))
 		argv_array_push(&repack, "-a");
 	else {
 		argv_array_push(&repack, "-A");
 		if (prune_expire)
 			argv_array_pushf(&repack, "--unpack-unreachable=%s", prune_expire);
 	}
 }

 static int need_to_gc(void)
 {
 	/*
 	 * Setting gc.auto to 0 or negative can disable the
 	 * automatic gc.
 	 */
 	if (gc_auto_threshold <= 0)
 		return 0;

 	/*
 	 * If there are too many loose objects, but not too many
 	 * packs, we run "repack -d -l".  If there are too many packs,
 	 * we run "repack -A -d -l".  Otherwise we tell the caller
 	 * there is no need.
 	 */
 	if (too_many_packs())
 		add_repack_all_option();
 	else if (!too_many_loose_objects())
 		return 0;

 	if (run_hook_le(NULL, "pre-auto-gc", NULL))
 		return 0;
 	return 1;
 }

 /* return NULL on success, else hostname running the gc */
 static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
 {
 	static struct lock_file lock;
 	char my_host[128];
 	struct strbuf sb = STRBUF_INIT;
 	struct stat st;
 	uintmax_t pid;
 	FILE *fp;
 	int fd;
 	char *pidfile_path;

 	if (is_tempfile_active(&pidfile))
 		/* already locked */
 		return NULL;

 	if (gethostname(my_host, sizeof(my_host)))
 		strcpy(my_host, "unknown");

 	pidfile_path = git_pathdup("gc.pid");
 	fd = hold_lock_file_for_update(&lock, pidfile_path,
 				       LOCK_DIE_ON_ERROR);
 	if (!force) {
 		static char locking_host[128];
 		int should_exit;
 		fp = fopen(pidfile_path, "r");
 		memset(locking_host, 0, sizeof(locking_host));
 		should_exit =
 			fp != NULL &&
 			!fstat(fileno(fp), &st) &&
 			/*
 			 * 12 hour limit is very generous as gc should
 			 * never take that long. On the other hand we
 			 * don't really need a strict limit here,
 			 * running gc --auto one day late is not a big
 			 * problem. --force can be used in manual gc
 			 * after the user verifies that no gc is
 			 * running.
 			 */
 			time(NULL) - st.st_mtime <= 12 * 3600 &&
 			fscanf(fp, "%"PRIuMAX" %127c", &pid, locking_host) == 2 &&
 			/* be gentle to concurrent "gc" on remote hosts */
 			(strcmp(locking_host, my_host) || !kill(pid, 0) || errno == EPERM);
 		if (fp != NULL)
 			fclose(fp);
 		if (should_exit) {
 			if (fd >= 0)
 				rollback_lock_file(&lock);
 			*ret_pid = pid;
 			free(pidfile_path);
 			return locking_host;
 		}
 	}

 	strbuf_addf(&sb, "%"PRIuMAX" %s",
 		    (uintmax_t) getpid(), my_host);
 	write_in_full(fd, sb.buf, sb.len);
 	strbuf_release(&sb);
 	commit_lock_file(&lock);
 	register_tempfile(&pidfile, pidfile_path);
 	free(pidfile_path);
 	return NULL;
 }

 static int gc_before_repack(void)
 {
 	if (pack_refs && run_command_v_opt(pack_refs_cmd.argv, RUN_GIT_CMD))
 		return error(FAILED_RUN, pack_refs_cmd.argv[0]);

 	if (prune_reflogs && run_command_v_opt(reflog.argv, RUN_GIT_CMD))
 		return error(FAILED_RUN, reflog.argv[0]);

 	pack_refs = 0;
 	prune_reflogs = 0;
 	return 0;
 }

 int cmd_gc(int argc, const char **argv, const char *prefix)
 {
 	int aggressive = 0;
 	int auto_gc = 0;
 	int quiet = 0;
 	int force = 0;
 	const char *name;
 	pid_t pid;

 	struct option builtin_gc_options[] = {
 		OPT__QUIET(&quiet, N_("suppress progress reporting")),
 		{ OPTION_STRING, 0, "prune", &prune_expire, N_("date"),
 			N_("prune unreferenced objects"),
 			PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire },
 		OPT_BOOL(0, "aggressive", &aggressive, N_("be more thorough (increased runtime)")),
 		OPT_BOOL(0, "auto", &auto_gc, N_("enable auto-gc mode")),
 		OPT_BOOL(0, "force", &force, N_("force running gc even if there may be another gc running")),
 		OPT_END()
 	};

 	if (argc == 2 && !strcmp(argv[1], "-h"))
 		usage_with_options(builtin_gc_usage, builtin_gc_options);

 	argv_array_pushl(&pack_refs_cmd, "pack-refs", "--all", "--prune", NULL);
 	argv_array_pushl(&reflog, "reflog", "expire", "--all", NULL);
 	argv_array_pushl(&repack, "repack", "-d", "-l", NULL);
 	argv_array_pushl(&prune, "prune", "--expire", NULL);
 	argv_array_pushl(&prune_worktrees, "worktree", "prune", "--expire", NULL);
 	argv_array_pushl(&rerere, "rerere", "gc", NULL);

 	gc_config();

 	if (pack_refs < 0)
 		pack_refs = !is_bare_repository();

 	argc = parse_options(argc, argv, prefix, builtin_gc_options,
 			     builtin_gc_usage, 0);
 	if (argc > 0)
 		usage_with_options(builtin_gc_usage, builtin_gc_options);

 	if (aggressive) {
 		argv_array_push(&repack, "-f");
 		if (aggressive_depth > 0)
 			argv_array_pushf(&repack, "--depth=%d", aggressive_depth);
 		if (aggressive_window > 0)
 			argv_array_pushf(&repack, "--window=%d", aggressive_window);
 	}
 	if (quiet)
 		argv_array_push(&repack, "-q");

 	if (auto_gc) {
 		/*
 		 * Auto-gc should be least intrusive as possible.
 		 */
 		if (!need_to_gc())
 			return 0;
 		if (!quiet) {
 			if (detach_auto)
 				fprintf(stderr, _("Auto packing the repository in background for optimum performance.\n"));
 			else
 				fprintf(stderr, _("Auto packing the repository for optimum performance.\n"));
 			fprintf(stderr, _("See \"git help gc\" for manual housekeeping.\n"));
 		}
 		if (detach_auto) {
 			if (gc_before_repack())
 				return -1;
 			/*
 			 * failure to daemonize is ok, we'll continue
 			 * in foreground
 			 */
 			daemonize();
 		}
 	} else
 		add_repack_all_option();

 	name = lock_repo_for_gc(force, &pid);
 	if (name) {
 		if (auto_gc)
 			return 0; /* be quiet on --auto */
 		die(_("gc is already running on machine '%s' pid %"PRIuMAX" (use --force if not)"),
 		    name, (uintmax_t)pid);
 	}

 	if (gc_before_repack())
 		return -1;

 	if (run_command_v_opt(repack.argv, RUN_GIT_CMD))
 		return error(FAILED_RUN, repack.argv[0]);

 	if (prune_expire) {
 		argv_array_push(&prune, prune_expire);
 		if (quiet)
 			argv_array_push(&prune, "--no-progress");
 		if (run_command_v_opt(prune.argv, RUN_GIT_CMD))
 			return error(FAILED_RUN, prune.argv[0]);
 	}

 	if (prune_worktrees_expire) {
 		argv_array_push(&prune_worktrees, prune_worktrees_expire);
 		if (run_command_v_opt(prune_worktrees.argv, RUN_GIT_CMD))
 			return error(FAILED_RUN, prune_worktrees.argv[0]);
 	}

 	if (run_command_v_opt(rerere.argv, RUN_GIT_CMD))
 		return error(FAILED_RUN, rerere.argv[0]);

 	if (auto_gc && too_many_loose_objects())
 		warning(_("There are too many unreachable loose objects; "
 			"run 'git prune' to remove them."));

 	return 0;
 }
	/*
	* git gc builtin command
	*
	* Cleanup unreachable files and optimize the repository.
	*
	* Copyright (c) 2007 James Bowes
	*
	* Based on git-gc.sh, which is
	*
	* Copyright (c) 2006 Shawn O. Pearce
	*/

	#include "builtin.h"
	#include "tempfile.h"
	#include "lockfile.h"
	#include "parse-options.h"
	#include "run-command.h"
	#include "sigchain.h"
	#include "argv-array.h"
	#include "commit.h"

	#define FAILED_RUN "failed to run %s"

	static const char * const builtin_gc_usage[] = {
	N_("git gc [<options>]"),
	NULL
	};

	static int pack_refs = 1;
	static int prune_reflogs = 1;
	static int aggressive_depth = 250;
	static int aggressive_window = 250;
	static int gc_auto_threshold = 6700;
	static int gc_auto_pack_limit = 50;
	static int detach_auto = 1;
	static const char *prune_expire = "2.weeks.ago";
	static const char *prune_worktrees_expire = "3.months.ago";

	static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT;
	static struct argv_array reflog = ARGV_ARRAY_INIT;
	static struct argv_array repack = ARGV_ARRAY_INIT;
	static struct argv_array prune = ARGV_ARRAY_INIT;
	static struct argv_array prune_worktrees = ARGV_ARRAY_INIT;
	static struct argv_array rerere = ARGV_ARRAY_INIT;

	static struct tempfile pidfile;

	static void git_config_date_string(const char key, const char *output)
	{
	if (git_config_get_string_const(key, output))
	return;
	if (strcmp(*output, "now")) {
	unsigned long now = approxidate("now");
	if (approxidate(*output) >= now)
	git_die_config(key, _("Invalid %s: '%s'"), key, *output);
	}
	}

	static void gc_config(void)
	{
	const char *value;

	if (!git_config_get_value("gc.packrefs", &value)) {
	if (value && !strcmp(value, "notbare"))
	pack_refs = -1;
	else
	pack_refs = git_config_bool("gc.packrefs", value);
	}

	git_config_get_int("gc.aggressivewindow", &aggressive_window);
	git_config_get_int("gc.aggressivedepth", &aggressive_depth);
	git_config_get_int("gc.auto", &gc_auto_threshold);
	git_config_get_int("gc.autopacklimit", &gc_auto_pack_limit);
	git_config_get_bool("gc.autodetach", &detach_auto);
	git_config_date_string("gc.pruneexpire", &prune_expire);
	git_config_date_string("gc.worktreepruneexpire", &prune_worktrees_expire);
	git_config(git_default_config, NULL);
	}

	static int too_many_loose_objects(void)
	{
	/*
	* Quickly check if a "gc" is needed, by estimating how
	* many loose objects there are. Because SHA-1 is evenly
	* distributed, we can check only one and get a reasonable
	* estimate.
	*/
	char path[PATH_MAX];
	const char *objdir = get_object_directory();
	DIR *dir;
	struct dirent *ent;
	int auto_threshold;
	int num_loose = 0;
	int needed = 0;

	if (gc_auto_threshold <= 0)
	return 0;

	if (sizeof(path) <= snprintf(path, sizeof(path), "%s/17", objdir)) {
	warning(_("insanely long object directory %.*s"), 50, objdir);
	return 0;
	}
	dir = opendir(path);
	if (!dir)
	return 0;

	auto_threshold = (gc_auto_threshold + 255) / 256;
	while ((ent = readdir(dir)) != NULL) {
	if (strspn(ent->d_name, "0123456789abcdef") != 38 \|\|
	ent->d_name[38] != '\0')
	continue;
	if (++num_loose > auto_threshold) {
	needed = 1;
	break;
	}
	}
	closedir(dir);
	return needed;
	}

	static int too_many_packs(void)
	{
	struct packed_git *p;
	int cnt;

	if (gc_auto_pack_limit <= 0)
	return 0;

	prepare_packed_git();
	for (cnt = 0, p = packed_git; p; p = p->next) {
	if (!p->pack_local)
	continue;
	if (p->pack_keep)
	continue;
	/*
	* Perhaps check the size of the pack and count only
	* very small ones here?
	*/
	cnt++;
	}
	return gc_auto_pack_limit <= cnt;
	}

	static void add_repack_all_option(void)
	{
	if (prune_expire && !strcmp(prune_expire, "now"))
	argv_array_push(&repack, "-a");
	else {
	argv_array_push(&repack, "-A");
	if (prune_expire)
	argv_array_pushf(&repack, "--unpack-unreachable=%s", prune_expire);
	}
	}

	static int need_to_gc(void)
	{
	/*
	* Setting gc.auto to 0 or negative can disable the
	* automatic gc.
	*/
	if (gc_auto_threshold <= 0)
	return 0;

	/*
	* If there are too many loose objects, but not too many
	* packs, we run "repack -d -l". If there are too many packs,
	* we run "repack -A -d -l". Otherwise we tell the caller
	* there is no need.
	*/
	if (too_many_packs())
	add_repack_all_option();
	else if (!too_many_loose_objects())
	return 0;

	if (run_hook_le(NULL, "pre-auto-gc", NULL))
	return 0;
	return 1;
	}

	/* return NULL on success, else hostname running the gc */
	static const char lock_repo_for_gc(int force, pid_t ret_pid)
	{
	static struct lock_file lock;
	char my_host[128];
	struct strbuf sb = STRBUF_INIT;
	struct stat st;
	uintmax_t pid;
	FILE *fp;
	int fd;
	char *pidfile_path;

	if (is_tempfile_active(&pidfile))
	/* already locked */
	return NULL;

	if (gethostname(my_host, sizeof(my_host)))
	strcpy(my_host, "unknown");

	pidfile_path = git_pathdup("gc.pid");
	fd = hold_lock_file_for_update(&lock, pidfile_path,
	LOCK_DIE_ON_ERROR);
	if (!force) {
	static char locking_host[128];
	int should_exit;
	fp = fopen(pidfile_path, "r");
	memset(locking_host, 0, sizeof(locking_host));
	should_exit =
	fp != NULL &&
	!fstat(fileno(fp), &st) &&
	/*
	* 12 hour limit is very generous as gc should
	* never take that long. On the other hand we
	* don't really need a strict limit here,
	* running gc --auto one day late is not a big
	* problem. --force can be used in manual gc
	* after the user verifies that no gc is
	* running.
	*/
	time(NULL) - st.st_mtime <= 12 * 3600 &&
	fscanf(fp, "%"PRIuMAX" %127c", &pid, locking_host) == 2 &&
	/* be gentle to concurrent "gc" on remote hosts */
	(strcmp(locking_host, my_host) \|\| !kill(pid, 0) \|\| errno == EPERM);
	if (fp != NULL)
	fclose(fp);
	if (should_exit) {
	if (fd >= 0)
	rollback_lock_file(&lock);
	*ret_pid = pid;
	free(pidfile_path);
	return locking_host;
	}
	}

	strbuf_addf(&sb, "%"PRIuMAX" %s",
	(uintmax_t) getpid(), my_host);
	write_in_full(fd, sb.buf, sb.len);
	strbuf_release(&sb);
	commit_lock_file(&lock);
	register_tempfile(&pidfile, pidfile_path);
	free(pidfile_path);
	return NULL;
	}

	static int gc_before_repack(void)
	{
	if (pack_refs && run_command_v_opt(pack_refs_cmd.argv, RUN_GIT_CMD))
	return error(FAILED_RUN, pack_refs_cmd.argv[0]);

	if (prune_reflogs && run_command_v_opt(reflog.argv, RUN_GIT_CMD))
	return error(FAILED_RUN, reflog.argv[0]);

	pack_refs = 0;
	prune_reflogs = 0;
	return 0;
	}

	int cmd_gc(int argc, const char *argv, const char prefix)
	{
	int aggressive = 0;
	int auto_gc = 0;
	int quiet = 0;
	int force = 0;
	const char *name;
	pid_t pid;

	struct option builtin_gc_options[] = {
	OPT__QUIET(&quiet, N_("suppress progress reporting")),
	{ OPTION_STRING, 0, "prune", &prune_expire, N_("date"),
	N_("prune unreferenced objects"),
	PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire },
	OPT_BOOL(0, "aggressive", &aggressive, N_("be more thorough (increased runtime)")),
	OPT_BOOL(0, "auto", &auto_gc, N_("enable auto-gc mode")),
	OPT_BOOL(0, "force", &force, N_("force running gc even if there may be another gc running")),
	OPT_END()
	};

	if (argc == 2 && !strcmp(argv[1], "-h"))
	usage_with_options(builtin_gc_usage, builtin_gc_options);

	argv_array_pushl(&pack_refs_cmd, "pack-refs", "--all", "--prune", NULL);
	argv_array_pushl(&reflog, "reflog", "expire", "--all", NULL);
	argv_array_pushl(&repack, "repack", "-d", "-l", NULL);
	argv_array_pushl(&prune, "prune", "--expire", NULL);
	argv_array_pushl(&prune_worktrees, "worktree", "prune", "--expire", NULL);
	argv_array_pushl(&rerere, "rerere", "gc", NULL);

	gc_config();

	if (pack_refs < 0)
	pack_refs = !is_bare_repository();

	argc = parse_options(argc, argv, prefix, builtin_gc_options,
	builtin_gc_usage, 0);
	if (argc > 0)
	usage_with_options(builtin_gc_usage, builtin_gc_options);

	if (aggressive) {
	argv_array_push(&repack, "-f");
	if (aggressive_depth > 0)
	argv_array_pushf(&repack, "--depth=%d", aggressive_depth);
	if (aggressive_window > 0)
	argv_array_pushf(&repack, "--window=%d", aggressive_window);
	}
	if (quiet)
	argv_array_push(&repack, "-q");

	if (auto_gc) {
	/*
	* Auto-gc should be least intrusive as possible.
	*/
	if (!need_to_gc())
	return 0;
	if (!quiet) {
	if (detach_auto)
	fprintf(stderr, _("Auto packing the repository in background for optimum performance.\n"));
	else
	fprintf(stderr, _("Auto packing the repository for optimum performance.\n"));
	fprintf(stderr, _("See \"git help gc\" for manual housekeeping.\n"));
	}
	if (detach_auto) {
	if (gc_before_repack())
	return -1;
	/*
	* failure to daemonize is ok, we'll continue
	* in foreground
	*/
	daemonize();
	}
	} else
	add_repack_all_option();

	name = lock_repo_for_gc(force, &pid);
	if (name) {
	if (auto_gc)
	return 0; /* be quiet on --auto */
	die(_("gc is already running on machine '%s' pid %"PRIuMAX" (use --force if not)"),
	name, (uintmax_t)pid);
	}

	if (gc_before_repack())
	return -1;

	if (run_command_v_opt(repack.argv, RUN_GIT_CMD))
	return error(FAILED_RUN, repack.argv[0]);

	if (prune_expire) {
	argv_array_push(&prune, prune_expire);
	if (quiet)
	argv_array_push(&prune, "--no-progress");
	if (run_command_v_opt(prune.argv, RUN_GIT_CMD))
	return error(FAILED_RUN, prune.argv[0]);
	}

	if (prune_worktrees_expire) {
	argv_array_push(&prune_worktrees, prune_worktrees_expire);
	if (run_command_v_opt(prune_worktrees.argv, RUN_GIT_CMD))
	return error(FAILED_RUN, prune_worktrees.argv[0]);
	}

	if (run_command_v_opt(rerere.argv, RUN_GIT_CMD))
	return error(FAILED_RUN, rerere.argv[0]);

	if (auto_gc && too_many_loose_objects())
	warning(_("There are too many unreachable loose objects; "
	"run 'git prune' to remove them."));

	return 0;
	}