rerere: libify rerere_clear() and rerere_gc()

This moves the two features from builtin/rerere.c to a more library-ish
portion of the codebase.  No behaviour change.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/rerere.c

@@ -12,74 +12,6 @@ static const char * const rerere_usage[] = {
 	NULL,
 };
 
-/* these values are days */
-static int cutoff_noresolve = 15;
-static int cutoff_resolve = 60;
-
-static time_t rerere_created_at(const char *name)
-{
-	struct stat st;
-	return stat(rerere_path(name, "preimage"), &st) ? (time_t) 0 : st.st_mtime;
-}
-
-static time_t rerere_last_used_at(const char *name)
-{
-	struct stat st;
-	return stat(rerere_path(name, "postimage"), &st) ? (time_t) 0 : st.st_mtime;
-}
-
-static void unlink_rr_item(const char *name)
-{
-	unlink(rerere_path(name, "thisimage"));
-	unlink(rerere_path(name, "preimage"));
-	unlink(rerere_path(name, "postimage"));
-	rmdir(git_path("rr-cache/%s", name));
-}
-
-static int git_rerere_gc_config(const char *var, const char *value, void *cb)
-{
-	if (!strcmp(var, "gc.rerereresolved"))
-		cutoff_resolve = git_config_int(var, value);
-	else if (!strcmp(var, "gc.rerereunresolved"))
-		cutoff_noresolve = git_config_int(var, value);
-	else
-		return git_default_config(var, value, cb);
-	return 0;
-}
-
-static void garbage_collect(struct string_list *rr)
-{
-	struct string_list to_remove = STRING_LIST_INIT_DUP;
-	DIR *dir;
-	struct dirent *e;
-	int i, cutoff;
-	time_t now = time(NULL), then;
-
-	git_config(git_rerere_gc_config, NULL);
-	dir = opendir(git_path("rr-cache"));
-	if (!dir)
-		die_errno("unable to open rr-cache directory");
-	while ((e = readdir(dir))) {
-		if (is_dot_or_dotdot(e->d_name))
-			continue;
-
-		then = rerere_last_used_at(e->d_name);
-		if (then) {
-			cutoff = cutoff_resolve;
-		} else {
-			then = rerere_created_at(e->d_name);
-			if (!then)
-				continue;
-			cutoff = cutoff_noresolve;
-		}
-		if (then < now - cutoff * 86400)
-			string_list_append(&to_remove, e->d_name);
-	}
-	for (i = 0; i < to_remove.nr; i++)
-		unlink_rr_item(to_remove.items[i].string);
-	string_list_clear(&to_remove, 0);
-}
-
 static int outf(void *dummy, mmbuffer_t *ptr, int nbuf)
 {
 	int i;
@@ -148,14 +80,9 @@ int cmd_rerere(int argc, const char **argv, const char *prefix)
 		return 0;
 
 	if (!strcmp(argv[0], "clear")) {
-		for (i = 0; i < merge_rr.nr; i++) {
-			const char *name = (const char *)merge_rr.items[i].util;
-			if (!has_rerere_resolution(name))
-				unlink_rr_item(name);
-		}
-		unlink_or_warn(git_path("MERGE_RR"));
+		rerere_clear(&merge_rr);
 	} else if (!strcmp(argv[0], "gc"))
-		garbage_collect(&merge_rr);
+		rerere_gc(&merge_rr);
 	else if (!strcmp(argv[0], "status"))
 		for (i = 0; i < merge_rr.nr; i++)
 			printf("%s\n", merge_rr.items[i].string);

rerere.c

@@ -671,3 +671,87 @@ int rerere_forget(const char **pathspec)
 	}
 	return write_rr(&merge_rr, fd);
 }
+
+static time_t rerere_created_at(const char *name)
+{
+	struct stat st;
+	return stat(rerere_path(name, "preimage"), &st) ? (time_t) 0 : st.st_mtime;
+}
+
+static time_t rerere_last_used_at(const char *name)
+{
+	struct stat st;
+	return stat(rerere_path(name, "postimage"), &st) ? (time_t) 0 : st.st_mtime;
+}
+
+static void unlink_rr_item(const char *name)
+{
+	unlink(rerere_path(name, "thisimage"));
+	unlink(rerere_path(name, "preimage"));
+	unlink(rerere_path(name, "postimage"));
+	rmdir(git_path("rr-cache/%s", name));
+}
+
+struct rerere_gc_config_cb {
+	int cutoff_noresolve;
+	int cutoff_resolve;
+};
+
+static int git_rerere_gc_config(const char *var, const char *value, void *cb)
+{
+	struct rerere_gc_config_cb *cf = cb;
+
+	if (!strcmp(var, "gc.rerereresolved"))
+		cf->cutoff_resolve = git_config_int(var, value);
+	else if (!strcmp(var, "gc.rerereunresolved"))
+		cf->cutoff_noresolve = git_config_int(var, value);
+	else
+		return git_default_config(var, value, cb);
+	return 0;
+}
+
+void rerere_gc(struct string_list *rr)
+{
+	struct string_list to_remove = STRING_LIST_INIT_DUP;
+	DIR *dir;
+	struct dirent *e;
+	int i, cutoff;
+	time_t now = time(NULL), then;
+	struct rerere_gc_config_cb cf = { 15, 60 };
+
+	git_config(git_rerere_gc_config, &cf);
+	dir = opendir(git_path("rr-cache"));
+	if (!dir)
+		die_errno("unable to open rr-cache directory");
+	while ((e = readdir(dir))) {
+		if (is_dot_or_dotdot(e->d_name))
+			continue;
+
+		then = rerere_last_used_at(e->d_name);
+		if (then) {
+			cutoff = cf.cutoff_resolve;
+		} else {
+			then = rerere_created_at(e->d_name);
+			if (!then)
+				continue;
+			cutoff = cf.cutoff_noresolve;
+		}
+		if (then < now - cutoff * 86400)
+			string_list_append(&to_remove, e->d_name);
+	}
+	for (i = 0; i < to_remove.nr; i++)
+		unlink_rr_item(to_remove.items[i].string);
+	string_list_clear(&to_remove, 0);
+}
+
+void rerere_clear(struct string_list *merge_rr)
+{
+	int i;
+
+	for (i = 0; i < merge_rr->nr; i++) {
+		const char *name = (const char *)merge_rr->items[i].util;
+		if (!has_rerere_resolution(name))
+			unlink_rr_item(name);
+	}
+	unlink_or_warn(git_path("MERGE_RR"));
+}

rerere.h

@@ -19,6 +19,8 @@ extern const char *rerere_path(const char *hex, const char *file);
 extern int has_rerere_resolution(const char *hex);
 extern int rerere_forget(const char **);
 extern int rerere_remaining(struct string_list *);
+extern void rerere_clear(struct string_list *);
+extern void rerere_gc(struct string_list *);
 
 #define OPT_RERERE_AUTOUPDATE(v) OPT_UYN(0, "rerere-autoupdate", (v), \
 	"update the index with reused conflict resolution if possible")