Implement DirectoryScanner object

src/file_system.h

@@ -7,6 +7,20 @@ typedef struct {
     uint64_t data;
 } Handle;
 
+#ifdef _WIN32
+typedef struct {
+    HANDLE handle;
+    WIN32_FIND_DATA find_data;
+    bool first;
+    bool done;
+} DirectoryScanner;
+#else
+typedef struct {
+    DIR *d;
+    struct dirent *e;
+} DirectoryScanner;
+#endif
+
 int  file_open(string path, Handle *fd);
 void file_close(Handle fd);
 int  file_lock(Handle fd);
@@ -22,4 +36,8 @@ int  remove_file_or_dir(string path);
 int  get_full_path(string path, char *dst);
 int  file_read_all(string path, string *data);
 
+int  directory_scanner_init(DirectoryScanner *scanner, string path);
+int  directory_scanner_next(DirectoryScanner *scanner, string *name);
+void directory_scanner_free(DirectoryScanner *scanner);
+
 #endif // FILE_SYSTEM_INCLUDED