Graceful fallback to readonly mode if RDB can't be opened readwrite

database_info.c

@@ -717,7 +717,7 @@ static int database_cursor_open(libretrodb_t *db,
    const char *error     = NULL;
    libretrodb_query_t *q = NULL;
 
-   if ((libretrodb_open(path, db)) != 0)
+   if ((libretrodb_open(path, db, false)) != 0)
       return -1;
 
    if (query)

libretro-db/libretrodb.c

@@ -46,45 +46,46 @@
 
 struct node_iter_ctx
 {
-	libretrodb_t *db;
-	libretrodb_index_t *idx;
+   libretrodb_t *db;
+   libretrodb_index_t *idx;
 };
 
 struct libretrodb
 {
-	RFILE *fd;
+   RFILE *fd;
    char *path;
-	uint64_t root;
-	uint64_t count;
-	uint64_t first_index_offset;
+   bool can_write;
+   uint64_t root;
+   uint64_t count;
+   uint64_t first_index_offset;
 };
 
 struct libretrodb_index
 {
-	char name[50];
-	uint64_t key_size;
-	uint64_t next;
-	uint64_t count;
+   char name[50];
+   uint64_t key_size;
+   uint64_t next;
+   uint64_t count;
 };
 
 typedef struct libretrodb_metadata
 {
-	uint64_t count;
+   uint64_t count;
 } libretrodb_metadata_t;
 
 typedef struct libretrodb_header
 {
-	char magic_number[sizeof(MAGIC_NUMBER)];
-	uint64_t metadata_offset;
+   char magic_number[sizeof(MAGIC_NUMBER)];
+   uint64_t metadata_offset;
 } libretrodb_header_t;
 
 struct libretrodb_cursor
 {
    RFILE *fd;
-	libretrodb_query_t *query;
-	libretrodb_t *db;
-	int is_valid;
-	int eof;
+   libretrodb_query_t *query;
+   libretrodb_t *db;
+   int is_valid;
+   int eof;
 };
 
 static int libretrodb_validate_document(const struct rmsgpack_dom_value *doc)
@@ -180,16 +181,16 @@ void libretrodb_close(libretrodb_t *db)
    db->fd   = NULL;
 }
 
-int libretrodb_open(const char *path, libretrodb_t *db)
+int libretrodb_open(const char *path, libretrodb_t *db, bool write)
 {
    libretrodb_header_t header;
    libretrodb_metadata_t md;
    RFILE *fd = filestream_open(path,
-         RETRO_VFS_FILE_ACCESS_READ_WRITE | RETRO_VFS_FILE_ACCESS_UPDATE_EXISTING,
+         write ? RETRO_VFS_FILE_ACCESS_READ_WRITE | RETRO_VFS_FILE_ACCESS_UPDATE_EXISTING : RETRO_VFS_FILE_ACCESS_READ,
          RETRO_VFS_FILE_ACCESS_HINT_NONE);
-
+   db->can_write = write;
    if (!fd)
-      return -1;
+     return -1;
 
    if (!string_is_empty(db->path))
       free(db->path);
@@ -456,9 +457,14 @@ int libretrodb_create_index(libretrodb_t *db,
    uint64_t item_count              = 0;
    int rval                         = -1;
 
-   if (libretrodb_find_index(db, name, &idx) >= 0) {
+   if (libretrodb_find_index(db, name, &idx) >= 0)
+   {
      return 1;
    }
+   if (!db->can_write)
+   {
+     return -1;
+   }
 
    tree = bintree_new(node_compare, &field_size);
 

libretro-db/libretrodb.h

@@ -49,7 +49,7 @@ int libretrodb_create(RFILE *fd, libretrodb_value_provider value_provider, void
 
 void libretrodb_close(libretrodb_t *db);
 
-int libretrodb_open(const char *path, libretrodb_t *db);
+int libretrodb_open(const char *path, libretrodb_t *db, bool write);
 
 int libretrodb_create_index(libretrodb_t *db, const char *name,
       const char *field_name);

libretro-db/libretrodb_tool.c

@@ -60,7 +60,7 @@ int main(int argc, char ** argv)
    if (!db || !cur)
       goto error;
 
-   if ((rv = libretrodb_open(path, db)) != 0)
+   if ((rv = libretrodb_open(path, db, true)) != 0)
    {
       printf("Could not open db file '%s'\n", path);
       goto error;

menu/menu_explore.c

@@ -583,7 +583,7 @@ explore_state_t *menu_explore_build_list(const char *directory_playlist,
                ext_path[3] = 'b';
             }
 
-            if (libretrodb_open(tmp, newrdb.handle) != 0)
+            if (libretrodb_open(tmp, newrdb.handle, false) != 0)
             {
                /* Invalid RDB file */
                libretrodb_free(newrdb.handle);