Merge pull request phaserjs#1359 from pnstickne/wip-optimize-signal

Signal - memory optimization / reductions

Author: photonstorm

src/core/Signal.js

@@ -12,54 +12,49 @@
 * @constructor
 */
 Phaser.Signal = function () {
+};
+
+Phaser.Signal.prototype = {
 
     /**
-    * @property {Array.<Phaser.SignalBinding>} _bindings - Internal variable.
+    * @property {?Array.<Phaser.SignalBinding>} _bindings - Internal variable.
     * @private
     */
-    this._bindings = [];
+    _bindings: null,
 
     /**
     * @property {any} _prevParams - Internal variable.
     * @private
     */
-    this._prevParams = null;
-
-    // enforce dispatch to aways work on same context (#47)
-    var self = this;
-
-    /**
-    * @property {function} dispatch - The dispatch function is what sends the Signal out.
-    */
-    this.dispatch = function(){
-        Phaser.Signal.prototype.dispatch.apply(self, arguments);
-    };
+    _prevParams: null,
 
     /**
     * If Signal should keep record of previously dispatched parameters and
     * automatically execute listener during `add()`/`addOnce()` if Signal was
     * already dispatched before.
     * @property {boolean} memorize
     */
-    this.memorize = false;
+    memorize: false,
 
     /**
     * @property {boolean} _shouldPropagate
     * @private
     */
-    this._shouldPropagate = true;
+    _shouldPropagate: true,
 
     /**
     * If Signal is active and should broadcast events.
     * IMPORTANT: Setting this property during a dispatch will only affect the next dispatch, if you want to stop the propagation of a signal use `halt()` instead.
     * @property {boolean} active
     * @default
     */
-    this.active = true;
-
-};
+    active: true,
 
-Phaser.Signal.prototype = {
+    /**
+    * @property {function} _boundDispatch - The bound dispatch function, if any.
+    * @private
+    */
+    _boundDispatch: true,
 
     /**
     * @method Phaser.Signal#validateListener
@@ -121,6 +116,11 @@ Phaser.Signal.prototype = {
     */
     _addBinding: function (binding) {
 
+        if (!this._bindings)
+        {
+            this._bindings = [];
+        }
+
         //  Simplified insertion sort
         var n = this._bindings.length;
 
@@ -137,10 +137,18 @@ Phaser.Signal.prototype = {
     * @method Phaser.Signal#_indexOfListener
     * @private
     * @param {function} listener - Signal handler function.
+    * @param {object} [context=null] - Signal handler function.
     * @return {number} The index of the listener within the private bindings array.
     */
     _indexOfListener: function (listener, context) {
 
+        if (!this._bindings)
+        {
+            return -1;
+        }
+
+        if (typeof context === 'undefined') { context = null; }
+
         var n = this._bindings.length;
         var cur;
 
@@ -211,7 +219,7 @@ Phaser.Signal.prototype = {
     *
     * @method Phaser.Signal#remove
     * @param {function} listener - Handler function that should be removed.
-    * @param {object} [context] - Execution context (since you can add the same handler multiple times if executing in a different context).
+    * @param {object} [context=null] - Execution context (since you can add the same handler multiple times if executing in a different context).
     * @return {function} Listener handler function.
     */
     remove: function (listener, context) {
@@ -240,6 +248,11 @@ Phaser.Signal.prototype = {
 
         if (typeof context === 'undefined') { context = null; }
 
+        if (!this._bindings)
+        {
+            return;
+        }
+
         var n = this._bindings.length;
 
         while (n--)
@@ -273,7 +286,7 @@ Phaser.Signal.prototype = {
     */
     getNumListeners: function () {
 
-        return this._bindings.length;
+        return this._bindings ? this._bindings.length : 0;
 
     },
 
@@ -293,12 +306,14 @@ Phaser.Signal.prototype = {
     /**
     * Dispatch/Broadcast Signal to all listeners added to the queue.
     *
+    * To create a bound dispatch for this Signal, use {@link Phaser.Signal#boundDispatch}.
+    *
     * @method Phaser.Signal#dispatch
     * @param {any} [params] - Parameters that should be passed to each handler.
     */
     dispatch: function () {
 
-        if (!this.active)
+        if (!this.active || !this._bindings)
         {
             return;
         }
@@ -338,7 +353,10 @@ Phaser.Signal.prototype = {
     */
     forget: function() {
 
-        this._prevParams = null;
+        if (this._prevParams)
+        {
+            this._prevParams = null;
+        }
 
     },
 
@@ -352,8 +370,11 @@ Phaser.Signal.prototype = {
 
         this.removeAll();
 
-        delete this._bindings;
-        delete this._prevParams;
+        this._bindings = null;
+        if (this._prevParams)
+        {
+            this._prevParams = null;
+        }
 
     },
 
@@ -370,4 +391,22 @@ Phaser.Signal.prototype = {
 
 };
 
+/**
+* If the dispatch function needs to be passed somewhere, or called independently
+* of the Signal object, use this function.
+*
+* @memberof Phaser.Signal
+* @property {function} boundDispatch
+*/
+Object.defineProperty(Phaser.Signal.prototype, "boundDispatch", {
+
+    get: function () {
+        var _this = this;
+        return this._boundDispatch || (this._boundDispatch = function () {
+            return _this.dispatch.apply(_this, arguments);
+        });
+    }
+
+});
+
 Phaser.Signal.prototype.constructor = Phaser.Signal;

src/core/SignalBinding.js

@@ -15,7 +15,7 @@
 * @param {Phaser.Signal} signal - Reference to Signal object that listener is currently bound to.
 * @param {function} listener - Handler function bound to the signal.
 * @param {boolean} isOnce - If binding should be executed just once.
-* @param {object} [listenerContext] - Context on which listener will be executed (object that should represent the `this` variable inside listener function).
+* @param {object} [listenerContext=null] - Context on which listener will be executed (object that should represent the `this` variable inside listener function).
 * @param {number} [priority] - The priority level of the event listener. (default = 0).
 */
 Phaser.SignalBinding = function (signal, listener, isOnce, listenerContext, priority) {
@@ -26,51 +26,66 @@ Phaser.SignalBinding = function (signal, listener, isOnce, listenerContext, prio
     */
     this._listener = listener;
 
+    if (isOnce)
+    {
+        this._isOnce = true;
+    }
+
+    if (listenerContext != null) /* not null/undefined */
+    {
+        this.context = listenerContext;
+    }
+
     /**
-    * @property {boolean} _isOnce - If binding should be executed just once.
+    * @property {Phaser.Signal} _signal - Reference to Signal object that listener is currently bound to.
     * @private
     */
-    this._isOnce = isOnce;
+    this._signal = signal;
+
+    if (priority)
+    {
+        this._priority = priority;
+    }
+
+};
+
+Phaser.SignalBinding.prototype = {
 
     /**
-    * @property {object|undefined|null} context - Context on which listener will be executed (object that should represent the `this` variable inside listener function).
+    * @property {?object} context - Context on which listener will be executed (object that should represent the `this` variable inside listener function).
     */
-    this.context = listenerContext;
+    context: null,
 
     /**
-    * @property {Phaser.Signal} _signal - Reference to Signal object that listener is currently bound to.
+    * @property {boolean} _isOnce - If binding should be executed just once.
     * @private
     */
-    this._signal = signal;
+    _isOnce: false,
 
     /**
     * @property {number} _priority - Listener priority.
     * @private
     */
-    this._priority = priority || 0;
+    _priority: 0,
 
     /**
     * @property {number} callCount - The number of times the handler function has been called.
     */
-    this.callCount = 0;
+    callCount: 0,
 
     /**
     * If binding is active and should be executed.
     * @property {boolean} active
     * @default
     */
-    this.active = true;
+    active: true,
 
     /**
     * Default parameters passed to listener during `Signal.dispatch` and `SignalBinding.execute` (curried parameters).
     * @property {array|null} params
     * @default
     */
-    this.params = null;
-
-};
-
-Phaser.SignalBinding.prototype = {
+    params: null,
 
     /**
     * Call listener passing arbitrary parameters.