Another attempt at avoiding overflowing the callstack on geocoderDataIterator: every tenth time we call a callback, call it via setImmediate to reset the stack

lib/mbtiles.js

@@ -615,6 +615,9 @@ MBTiles.prototype.putGeocoderData = function(type, shard, data, callback) {
     });
 };
 
+var stackCounter = 0;
+var stackMax = 10;
+
 // Implements carmen#geocoderDataIterator method.
 MBTiles.prototype.geocoderDataIterator = function(type) {
     var chunkSize = 100;
@@ -625,6 +628,20 @@ MBTiles.prototype.geocoderDataIterator = function(type) {
     var doneSentinel = {};
     var _this = this;
 
+    // every tenth callback call (globally) do it via setImmediate
+    // to avoid callback loops that blow the callstack
+    var checkStack = function(cb, arg) {
+        if (stackCounter >= stackMax) {
+            stackCounter = 0;
+            setImmediate(function() {
+                cb(arg);
+            })
+        } else {
+            stackCounter += 1;
+            cb(arg);
+        }
+    }
+
     var sending = false;
     var sendIfAvailable = function() {
         if (sending) return;
@@ -633,12 +650,12 @@ MBTiles.prototype.geocoderDataIterator = function(type) {
         while (nextQueue.length && dataQueue.length) {
             var nextCb = nextQueue.shift(), data;
             if (dataQueue[0] == doneSentinel) {
-                nextCb({value: undefined, done: true});
+                checkStack(nextCb, {value: undefined, done: true});
             } else {
                 data = dataQueue.shift();
                 maybeRefillBuffer();
 
-                nextCb({value: {shard: data.shard, data: zlib.inflateSync(data.data)}, done: false});
+                checkStack(nextCb, {value: {shard: data.shard, data: zlib.inflateSync(data.data)}, done: false});
             }
         }