switch to using native zlib, inflate works, odd test failures for deflate

lib/mbtiles.js

@@ -2,7 +2,7 @@ var _ = require('underscore'),
     fs = require('fs'),
     Step = require('step'),
     crypto = require('crypto'),
-    _zlib = require('_zlib'),
+    zlib = require('zlib'),
     path = require('path'),
     url = require('url'),
     qs = require('querystring'),
@@ -215,8 +215,9 @@ MBTiles.prototype.getGrid = function(z, x, y, callback) {
             }
             if (err) return callback(err);
 
+            /*
             try {
-                var grid = _zlib.inflate(
+                var grid = zlib.inflate(
                            !Buffer.isBuffer(row.grid)
                            ? new Buffer(row.grid, 'binary')
                            : row.grid
@@ -231,6 +232,24 @@ MBTiles.prototype.getGrid = function(z, x, y, callback) {
             }
 
             callback(null, result);
+            */
+
+            zlib.inflate(!Buffer.isBuffer(row.grid)
+                           ? new Buffer(row.grid, 'binary')
+                           : row.grid
+                         , function(err,buffer) {
+                                if (err) {
+                                    return callback(new Error('Grid is invalid:' + err.message));
+                                }
+                                var data = rows.reduce(function(memo, r) {
+                                        memo[r.key_name] = JSON.parse(r.key_json);
+                                        return memo;
+                                    }, {});
+                                var result = _(JSON.parse(buffer.toString())).extend({ data: data });
+                                
+                                callback(null, result);
+            });
+            
         }
     );
 };
@@ -565,13 +584,23 @@ MBTiles.prototype.putGrid = function(z, x, y, data, callback) {
     var id = crypto.createHash('md5').update(json).digest('hex');
     if (!this._gridCache[id]) {
         // This corresponds to the grid_utfgrid table.
-        this._gridCache[id] = _zlib.deflate(new Buffer(json, 'utf8'));
 
-        // This corresponds to the grid_key table.
+        /*
-        this._keyCache[id] = Object.keys(data.data || {});
+        this._gridCache[id] = zlib.deflate(new Buffer(json, 'utf8'));
+        */
         
-        // This corresponds to the keymap table.
+        Step(function() {
-        _(this._dataCache).extend(data.data || {});
+            zlib.deflate(new Buffer(json, 'utf8'),this);
+        }, function(err,buffer) {
+            if (err) return callback(err);
+            this._gridCache[id] = buffer;
+            // This corresponds to the grid_key table.
+            this._keyCache[id] = Object.keys(data.data || {});
+    
+            // This corresponds to the keymap table.
+            _(this._dataCache).extend(data.data || {});
+        }
+        );
     }
 
     // This corresponds to the map table.