From a0c816c691ed519aafdc6f0ee43719d87c886cc9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Konstantin=20Ka=CC=88fer?= <github@kkaefer.com>
Date: Mon, 18 Jul 2011 14:21:50 +0200
Subject: [PATCH] check that the file is in write mode

---
 lib/mbtiles.js | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/mbtiles.js b/lib/mbtiles.js
index a0b98d5..823ecbc 100644
--- a/lib/mbtiles.js
+++ b/lib/mbtiles.js
@@ -565,6 +565,7 @@ MBTiles.prototype.putTile = function(z, x, y, data, callback) {
 MBTiles.prototype.putGrid = function(z, x, y, data, callback) {
     if (typeof callback !== 'function') throw new Error('Callback needed');
     if (!this.open) return callback(new Error('MBTiles not yet loaded'));
+    if (!this._isWritable) return callback(new Error('MBTiles not in write mode'));
 
     // Flip Y coordinate because MBTiles files are TMS.
     y = (1 << z) - 1 - y;