[PATCH] config: if mtime (or size) of the config file changed since last read, reread it

@@ -13,6 +13,7 @@ #define MAXNAME (256)
 static const char *contents = NULL;
 static int config_length = 0, config_offset = 0;
 static const char *config_file_name;
+static time_t config_file_mtime = 0;
 static int config_linenr;
 static int get_next_char(void)
 {

@@ -255,23 +256,26 @@ int git_default_config(const char *var, 
 int git_config_from_file(config_fn_t fn, const char *filename)
 {
 	int ret, in_fd;
+	struct stat st;
 
 	config_offset = 0;
 
+	in_fd = open(filename, O_RDONLY);
+	fstat(in_fd, &st);
+
 	if (contents) {
-		if (!strcmp(config_file_name, filename))
+		if (!strcmp(config_file_name, filename)
+				&& config_file_mtime == st.st_mtime
+				&& config_length == st.st_size) {
+			close(in_fd);
 			return git_parse_file(fn);
+		}
 		munmap((char*)contents, config_length);
 		free((char*)config_file_name);
 	}
 
-	in_fd = open(filename, O_RDONLY);
-
 	ret = -1;
 	if (in_fd > 0) {
-		struct stat st;
-
-		fstat(in_fd, &st);
 		config_length = st.st_size;
 		contents = mmap(NULL, config_length, PROT_READ, MAP_PRIVATE,
 				in_fd, 0);

@@ -261,6 +261,10 @@ int git_config_from_file(config_fn_t fn,
 	config_offset = 0;
 
 	in_fd = open(filename, O_RDONLY);
+	if (in_fd < 0 && ENOENT != errno )
+		die("opening %s: %s", config_file_name,
+				strerror(errno));
+
 	fstat(in_fd, &st);
 
 	if (contents) {

@@ -288,9 +292,6 @@ int git_config_from_file(config_fn_t fn,
 	} else {
 		contents = NULL;
 		config_length = 0;
-		if (in_fd < 0 && ENOENT != errno )
-			die("opening %s: %s", config_file_name,
-					strerror(errno));
 	}
 
 	return ret;