Ditch inflateSync in favor of plain inflate; test iteration order; add d3-queue dep

lib/mbtiles.js

@@ -9,6 +9,7 @@ var sm = new (require('sphericalmercator'));
 var sqlite3 = require('sqlite3');
 var tiletype = require('tiletype');
 var ZXYStream = require('./zxystream');
+var queue = require('d3-queue').queue;
 
 function noop(err) {
     if (err) throw err;
@@ -625,34 +626,42 @@ MBTiles.prototype.geocoderDataIterator = function(type) {
     var doneSentinel = {};
     var _this = this;
 
+    var zlibQueue = queue(1);
+    var inflate = function(data, callback) {
+        zlibQueue.defer(function(cb) {
+            zlib.inflate(data, function(err, buf) {
+                callback(err, buf);
+                cb();
+            });
+        });
+    }
+
     var sending = false;
     var sendIfAvailable = function() {
         if (sending) return;
         sending = true;
 
         while (nextQueue.length && dataQueue.length) {
-            var nextCb = nextQueue.shift(), data, cbValue;
+            var nextCb = nextQueue.shift(), data;
             if (dataQueue[0] == doneSentinel) {
-                cbValue = {
-                    err: null,
-                    row: {value: undefined, done: true}
-                }
+                (function(nextCb) {
+                    setImmediate(function() {
+                        nextCb(null, {value: undefined, done: true});
+                    });
+                })(nextCb);
             } else {
                 data = dataQueue.shift();
                 maybeRefillBuffer();
 
-                cbValue = {
-                    err: data.err,
-                    row: {value: {shard: data.row.shard, data: zlib.inflateSync(data.row.data)}, done: false}
-                };
+                (function(nextCb, cbValue) {
+                    inflate(data.row.data, function(err, buf) {
+                        nextCb(
+                            data.err,
+                            {value: {shard: data.row.shard, data: buf}, done: false}
+                        );
+                    })
+                })(nextCb, data);
             }
-            // bind the callback and data now so that they don't change before the setImmediate
-            // callback is executed
-            (function(nextCb, cbValue) {
-                setImmediate(function() {
-                    nextCb(cbValue.err, cbValue.row);
-                });
-            })(nextCb, cbValue);
         }
 
         sending = false;