1 files changed, 196 insertions, 22 deletions

diff --git a/builtin-gc.c b/builtin-gc.c
index 3b1f8c2f3..7d3e9cc7a 100644
--- a/builtin-gc.c
+++ b/builtin-gc.c
@@ -10,54 +10,221 @@
  * Copyright (c) 2006 Shawn O. Pearce
  */
 
+#include "builtin.h"
 #include "cache.h"
+#include "parse-options.h"
 #include "run-command.h"
 
 #define FAILED_RUN "failed to run %s"
 
-static const char builtin_gc_usage[] = "git-gc [--prune]";
+static const char * const builtin_gc_usage[] = {
+	"git gc [options]",
+	NULL
+};
 
-static int pack_refs = -1;
+static int pack_refs = 1;
+static int aggressive_window = 250;
+static int gc_auto_threshold = 6700;
+static int gc_auto_pack_limit = 50;
+static const char *prune_expire = "2.weeks.ago";
 
-static const char *argv_pack_refs[] = {"pack-refs", "--prune", NULL};
+#define MAX_ADD 10
+static const char *argv_pack_refs[] = {"pack-refs", "--all", "--prune", NULL};
 static const char *argv_reflog[] = {"reflog", "expire", "--all", NULL};
-static const char *argv_repack[] = {"repack", "-a", "-d", "-l", NULL};
-static const char *argv_prune[] = {"prune", NULL};
+static const char *argv_repack[MAX_ADD] = {"repack", "-d", "-l", NULL};
+static const char *argv_prune[] = {"prune", "--expire", NULL, NULL};
 static const char *argv_rerere[] = {"rerere", "gc", NULL};
 
-static int gc_config(const char *var, const char *value)
+static int gc_config(const char *var, const char *value, void *cb)
 {
 	if (!strcmp(var, "gc.packrefs")) {
-		if (!strcmp(value, "notbare"))
+		if (value && !strcmp(value, "notbare"))
 			pack_refs = -1;
 		else
 			pack_refs = git_config_bool(var, value);
 		return 0;
 	}
-	return git_default_config(var, value);
+	if (!strcmp(var, "gc.aggressivewindow")) {
+		aggressive_window = git_config_int(var, value);
+		return 0;
+	}
+	if (!strcmp(var, "gc.auto")) {
+		gc_auto_threshold = git_config_int(var, value);
+		return 0;
+	}
+	if (!strcmp(var, "gc.autopacklimit")) {
+		gc_auto_pack_limit = git_config_int(var, value);
+		return 0;
+	}
+	if (!strcmp(var, "gc.pruneexpire")) {
+		if (value && strcmp(value, "now")) {
+			unsigned long now = approxidate("now");
+			if (approxidate(value) >= now)
+				return error("Invalid %s: '%s'", var, value);
+		}
+		return git_config_string(&prune_expire, var, value);
+	}
+	return git_default_config(var, value, cb);
 }
 
-int cmd_gc(int argc, const char **argv, const char *prefix)
+static void append_option(const char **cmd, const char *opt, int max_length)
 {
 	int i;
-	int prune = 0;
 
-	git_config(gc_config);
+	for (i = 0; cmd[i]; i++)
+		;
+
+	if (i + 2 >= max_length)
+		die("Too many options specified");
+	cmd[i++] = opt;
+	cmd[i] = 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 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())
+		append_option(argv_repack,
+			      prune_expire && !strcmp(prune_expire, "now") ?
+			      "-a" : "-A",
+			      MAX_ADD);
+	else if (!too_many_loose_objects())
+		return 0;
+
+	if (run_hook(NULL, "pre-auto-gc", NULL))
+		return 0;
+	return 1;
+}
+
+int cmd_gc(int argc, const char **argv, const char *prefix)
+{
+	int aggressive = 0;
+	int auto_gc = 0;
+	int quiet = 0;
+	char buf[80];
+
+	struct option builtin_gc_options[] = {
+		{ OPTION_STRING, 0, "prune", &prune_expire, "date",
+			"prune unreferenced objects",
+			PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire },
+		OPT_BOOLEAN(0, "aggressive", &aggressive, "be more thorough (increased runtime)"),
+		OPT_BOOLEAN(0, "auto", &auto_gc, "enable auto-gc mode"),
+		OPT_BOOLEAN('q', "quiet", &quiet, "suppress progress reports"),
+		OPT_END()
+	};
+
+	git_config(gc_config, NULL);
 
 	if (pack_refs < 0)
 		pack_refs = !is_bare_repository();
 
-	for (i = 1; i < argc; i++) {
-		const char *arg = argv[i];
-		if (!strcmp(arg, "--prune")) {
-			prune = 1;
-			continue;
+	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) {
+		append_option(argv_repack, "-f", MAX_ADD);
+		append_option(argv_repack, "--depth=250", MAX_ADD);
+		if (aggressive_window > 0) {
+			sprintf(buf, "--window=%d", aggressive_window);
+			append_option(argv_repack, buf, MAX_ADD);
 		}
-		/* perhaps other parameters later... */
-		break;
 	}
-	if (i != argc)
-		usage(builtin_gc_usage);
+	if (quiet)
+		append_option(argv_repack, "-q", MAX_ADD);
+
+	if (auto_gc) {
+		/*
+		 * Auto-gc should be least intrusive as possible.
+		 */
+		if (!need_to_gc())
+			return 0;
+		fprintf(stderr, "Auto packing your repository for optimum "
+			"performance. You may also\n"
+			"run \"git gc\" manually. See "
+			"\"git help gc\" for more information.\n");
+	} else
+		append_option(argv_repack,
+			      prune_expire && !strcmp(prune_expire, "now")
+			      ? "-a" : "-A",
+			      MAX_ADD);
 
 	if (pack_refs && run_command_v_opt(argv_pack_refs, RUN_GIT_CMD))
 		return error(FAILED_RUN, argv_pack_refs[0]);
@@ -68,11 +235,18 @@ int cmd_gc(int argc, const char **argv, const char *prefix)
 	if (run_command_v_opt(argv_repack, RUN_GIT_CMD))
 		return error(FAILED_RUN, argv_repack[0]);
 
-	if (prune && run_command_v_opt(argv_prune, RUN_GIT_CMD))
-		return error(FAILED_RUN, argv_prune[0]);
+	if (prune_expire) {
+		argv_prune[2] = prune_expire;
+		if (run_command_v_opt(argv_prune, RUN_GIT_CMD))
+			return error(FAILED_RUN, argv_prune[0]);
+	}
 
 	if (run_command_v_opt(argv_rerere, RUN_GIT_CMD))
 		return error(FAILED_RUN, argv_rerere[0]);
 
+	if (auto_gc && too_many_loose_objects())
+		warning("There are too many unreachable loose objects; "
+			"run 'git prune' to remove them.");
+
 	return 0;
 }