safe_create_leading_directories(): introduce enum for return values

Instead of returning magic integer values (which a couple of callers
go to the trouble of distinguishing), return values from an enum.  Add
a docstring.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/init-db.c

@@ -515,10 +515,10 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
 				saved = shared_repository;
 				shared_repository = 0;
 				switch (safe_create_leading_directories_const(argv[0])) {
-				case -3:
+				case SCLD_EXISTS:
 					errno = EEXIST;
 					/* fallthru */
-				case -1:
+				case SCLD_FAILED:
 					die_errno(_("cannot mkdir %s"), argv[0]);
 					break;
 				default:

cache.h

@@ -736,8 +736,21 @@ enum sharedrepo {
 };
 int git_config_perm(const char *var, const char *value);
 int adjust_shared_perm(const char *path);
-int safe_create_leading_directories(char *path);
+
-int safe_create_leading_directories_const(const char *path);
+/*
+ * Create the directory containing the named path, using care to be
+ * somewhat safe against races.  Return one of the scld_error values
+ * to indicate success/failure.
+ */
+enum scld_error {
+	SCLD_OK = 0,
+	SCLD_FAILED = -1,
+	SCLD_PERMS = -2,
+	SCLD_EXISTS = -3
+};
+enum scld_error safe_create_leading_directories(char *path);
+enum scld_error safe_create_leading_directories_const(const char *path);
+
 int mkdir_in_gitdir(const char *path);
 extern void home_config_paths(char **global, char **xdg, char *file);
 extern char *expand_user_path(const char *path);

merge-recursive.c

@@ -693,7 +693,7 @@ static int make_room_for_path(struct merge_options *o, const char *path)
 	/* Make sure leading directories are created */
 	status = safe_create_leading_directories_const(path);
 	if (status) {
-		if (status == -3) {
+		if (status == SCLD_EXISTS) {
 			/* something else exists */
 			error(msg, path, _(": perhaps a D/F conflict?"));
 			return -1;

sha1_file.c

@@ -105,12 +105,12 @@ int mkdir_in_gitdir(const char *path)
 	return adjust_shared_perm(path);
 }
 
-int safe_create_leading_directories(char *path)
+enum scld_error safe_create_leading_directories(char *path)
 {
 	char *next_component = path + offset_1st_component(path);
-	int ret = 0;
+	enum scld_error ret = SCLD_OK;
 
-	while (!ret && next_component) {
+	while (ret == SCLD_OK && next_component) {
 		struct stat st;
 		char *slash = strchr(next_component, '/');
 
@@ -127,26 +127,26 @@ int safe_create_leading_directories(char *path)
 		if (!stat(path, &st)) {
 			/* path exists */
 			if (!S_ISDIR(st.st_mode))
-				ret = -3;
+				ret = SCLD_EXISTS;
 		} else if (mkdir(path, 0777)) {
 			if (errno == EEXIST &&
 			    !stat(path, &st) && S_ISDIR(st.st_mode))
 				; /* somebody created it since we checked */
 			else
-				ret = -1;
+				ret = SCLD_FAILED;
 		} else if (adjust_shared_perm(path)) {
-			ret = -2;
+			ret = SCLD_PERMS;
 		}
 		*slash = '/';
 	}
 	return ret;
 }
 
-int safe_create_leading_directories_const(const char *path)
+enum scld_error safe_create_leading_directories_const(const char *path)
 {
 	/* path points to cache entries, so xstrdup before messing with it */
 	char *buf = xstrdup(path);
-	int result = safe_create_leading_directories(buf);
+	enum scld_error result = safe_create_leading_directories(buf);
 	free(buf);
 	return result;
 }