index: Add `index_path_exists()`

This function checks if the converted path of a given index exists, or
not.

It also returns the converted path in `path` if the path exists.

1 files changed, 22 insertions, 0 deletions

diff --git a/index.c b/index.c
index d996b45..af65925 100644
--- a/index.c
+++ b/index.c
@@ -1,6 +1,7 @@
 #include <stddef.h>
 #include <stdint.h>
 #include <stdlib.h>
+#include <sys/stat.h>
 #include "index.h"
 #include "macros.h"
 
@@ -96,3 +97,24 @@ char *index_to_str(index *idx) {
 		return NULL;
 	}
 }
+
+int index_path_exists(index *idx, const char *root, char **path) {
+	char *dummy;
+	path = (path != NULL) ? path : &dummy;
+	for (int i = 0; i < 2; ++i) {
+		struct stat st;
+		*path = make_index_path(root, idx, i);
+		/* Does the index path exist? */
+		if (*path != NULL && stat(*path, &st) == 0) {
+			if (path == &dummy) {
+				free(*path);
+				*path = NULL;
+			}
+			return 1;
+		} else {
+			free(*path);
+			*path = NULL;
+		}
+	}
+	return 0;
+}