1 files changed, 244 insertions, 0 deletions
diff --git a/builtin-gc.c b/builtin-gc.c
new file mode 100644
index 0000000..799c263
--- /dev/null
+++ b/builtin-gc.c
@@ -0,0 +1,244 @@
+/*
+ * 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 "cache.h"
+#include "parse-options.h"
+#include "run-command.h"
+
+#define FAILED_RUN "failed to run %s"
+
+static const char * const builtin_gc_usage[] = {
+	"git-gc [options]",
+	NULL
+};
+
+static int pack_refs = 1;
+static int aggressive_window = -1;
+static int gc_auto_threshold = 6700;
+static int gc_auto_pack_limit = 20;
+
+#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[MAX_ADD] = {"repack", "-d", "-l", NULL};
+static const char *argv_prune[] = {"prune", NULL};
+static const char *argv_rerere[] = {"rerere", "gc", NULL};
+
+static int gc_config(const char *var, const char *value)
+{
+	if (!strcmp(var, "gc.packrefs")) {
+		if (!strcmp(value, "notbare"))
+			pack_refs = -1;
+		else
+			pack_refs = git_config_bool(var, value);
+		return 0;
+	}
+	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;
+	}
+	return git_default_config(var, value);
+}
+
+static void append_option(const char **cmd, const char *opt, int max_length)
+{
+	int i;
+
+	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) {
+		char path[PATH_MAX];
+		size_t len;
+		int keep;
+
+		if (!p->pack_local)
+			continue;
+		len = strlen(p->pack_name);
+		if (PATH_MAX <= len + 1)
+			continue; /* oops, give up */
+		memcpy(path, p->pack_name, len-5);
+		memcpy(path + len - 5, ".keep", 6);
+		keep = access(p->pack_name, F_OK) && (errno == ENOENT);
+		if (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 and gc.autopacklimit to 0 or negative can
+	 * disable the automatic gc.
+	 */
+	if (gc_auto_threshold <= 0 && gc_auto_pack_limit <= 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, "-A", MAX_ADD);
+	else if (!too_many_loose_objects())
+		return 0;
+	return 1;
+}
+
+int cmd_gc(int argc, const char **argv, const char *prefix)
+{
+	int prune = 0;
+	int aggressive = 0;
+	int auto_gc = 0;
+	char buf[80];
+
+	struct option builtin_gc_options[] = {
+		OPT_BOOLEAN(0, "prune", &prune, "prune unreferenced objects"),
+		OPT_BOOLEAN(0, "aggressive", &aggressive, "be more thorough (increased runtime)"),
+		OPT_BOOLEAN(0, "auto", &auto_gc, "enable auto-gc mode"),
+		OPT_END()
+	};
+
+	git_config(gc_config);
+
+	if (pack_refs < 0)
+		pack_refs = !is_bare_repository();
+
+	argc = parse_options(argc, argv, 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);
+		if (aggressive_window > 0) {
+			sprintf(buf, "--window=%d", aggressive_window);
+			append_option(argv_repack, buf, MAX_ADD);
+		}
+	}
+
+	if (auto_gc) {
+		/*
+		 * Auto-gc should be least intrusive as possible.
+		 */
+		prune = 0;
+		if (!need_to_gc())
+			return 0;
+		fprintf(stderr, "Packing your repository for optimum "
+			"performance. You may also\n"
+			"run \"git gc\" manually. See "
+			"\"git help gc\" for more information.\n");
+	} else {
+		/*
+		 * Use safer (for shared repos) "-A" option to
+		 * repack when not pruning. Auto-gc makes its
+		 * own decision.
+		 */
+		if (prune)
+			append_option(argv_repack, "-a", MAX_ADD);
+		else
+			append_option(argv_repack, "-A", MAX_ADD);
+	}
+
+	if (pack_refs && run_command_v_opt(argv_pack_refs, RUN_GIT_CMD))
+		return error(FAILED_RUN, argv_pack_refs[0]);
+
+	if (run_command_v_opt(argv_reflog, RUN_GIT_CMD))
+		return error(FAILED_RUN, argv_reflog[0]);
+
+	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 (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;
+}