Make CallbackWrapper a module

In theory this way it can be used anywhere else if needed, but right
now it's simply because it has to be placed somewhere and a module
seems the best place for an object definition (constructor, etc.)

4 files changed, 93 insertions, 67 deletions

diff --git a/CallbackWrapper.jsm b/CallbackWrapper.jsm
new file mode 100644
index 0000000..71237c4
--- /dev/null
+++ b/CallbackWrapper.jsm
@@ -0,0 +1,90 @@
+/*******************************************************************************
+
+    ηMatrix - a browser extension to black/white list requests.
+    Copyright (C) 2014-2019 The uMatrix/uBlock Origin authors
+    Copyright (C) 2019 Alessio Vanni
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see {http://www.gnu.org/licenses/}.
+
+    Home: https://gitlab.com/vannilla/ematrix
+    uMatrix Home: https://github.com/gorhill/uMatrix
+*/
+
+var EXPORTED_SYMBOLS = ['CallbackWrapper'];
+
+var junkyard = [];
+
+var CallbackWrapper = function (messageManager, channelName,
+				listenerId, requestId) {
+    // This allows to avoid creating a closure for every single
+    // message which expects an answer. Having a closure created
+    // each time a message is processed has been always bothering
+    // me. Another benefit of the implementation here is to reuse
+    // the callback proxy object, so less memory churning.
+    //
+    // https://developers.google.com/speed/articles/optimizing-javascript
+    // "Creating a closure is significantly slower then creating
+    // an inner function without a closure, and much slower than
+    // reusing a static function"
+    //
+    // http://hacksoflife.blogspot.ca/2015/01/the-four-horsemen-of-performance.html
+    // "the dreaded 'uniformly slow code' case where every
+    // function takes 1% of CPU and you have to make one hundred
+    // separate performance optimizations to improve performance
+    // at all"
+    //
+    // http://jsperf.com/closure-no-closure/2
+    this.callback = this.proxy.bind(this); // bind once
+    this.init(messageManager, channelName, listenerId, requestId);
+};
+
+CallbackWrapper.factory = function (messageManager, channelName,
+				    listenerId, requestId) {
+    let wrapper = junkyard.pop();
+    if (wrapper) {
+        wrapper.init(messageManager, channelName, listenerId, requestId);
+        return wrapper;
+    }
+    
+    return new CallbackWrapper(messageManager, channelName,
+			       listenerId, requestId);
+};
+
+CallbackWrapper.prototype.init = function (messageManager, channelName,
+					   listenerId, requestId) {
+    this.messageManager = messageManager;
+    this.channelName = channelName;
+    this.listenerId = listenerId;
+    this.requestId = requestId;
+};
+
+CallbackWrapper.prototype.proxy = function (response) {
+    let message = JSON.stringify({
+        requestId: this.requestId,
+        channelName: this.channelName,
+        msg: response !== undefined ? response : null
+    });
+
+    if (this.messageManager.sendAsyncMessage) {
+        this.messageManager.sendAsyncMessage(this.listenerId, message);
+    } else {
+        this.messageManager.broadcastAsyncMessage(this.listenerId, message);
+    }
+
+    // Mark for reuse
+    this.messageManager = this.channelName =
+	this.requestId = this.listenerId = null;
+    
+    junkyard.push(this);
+};
diff --git a/Makefile b/Makefile
index 754f0b3..87c1320 100644
--- a/Makefile
+++ b/Makefile
@@ -119,7 +119,7 @@ JS2 := js/httpsb.js js/i18n.js js/liquid-dict.js js/logger.js \
 # vapi-popup.js is apparently not needed on UXP
 # TODO: investigate wether or not it can be removed
 JS3 := js/tab.js js/traffic.js js/udom.js js/uritools.js js/user-rules.js \
-       js/usersettings.js js/utils.js js/xal.js
+       js/usersettings.js js/utils.js js/xal.js CallbackWrapper.jsm
 
 JS4 := js/vapi-client.js js/vapi-common.js js/vapi-background.js \
        js/vapi-popup.js js/vapi-tabs.js js/vapi-window.js \
diff --git a/js/vapi-background.js b/js/vapi-background.js
index 6c874f3..0da0638 100644
--- a/js/vapi-background.js
+++ b/js/vapi-background.js
@@ -69,72 +69,6 @@
 	}
     };
 
-    let CallbackWrapper = function (messageManager, channelName,
-				    listenerId, requestId) {
-	// This allows to avoid creating a closure for every single
-	// message which expects an answer. Having a closure created
-	// each time a message is processed has been always bothering
-	// me. Another benefit of the implementation here is to reuse
-	// the callback proxy object, so less memory churning.
-	//
-	// https://developers.google.com/speed/articles/optimizing-javascript
-	// "Creating a closure is significantly slower then creating
-	// an inner function without a closure, and much slower than
-	// reusing a static function"
-	//
-	// http://hacksoflife.blogspot.ca/2015/01/the-four-horsemen-of-performance.html
-	// "the dreaded 'uniformly slow code' case where every
-	// function takes 1% of CPU and you have to make one hundred
-	// separate performance optimizations to improve performance
-	// at all"
-	//
-	// http://jsperf.com/closure-no-closure/2
-	this.callback = this.proxy.bind(this); // bind once
-	this.init(messageManager, channelName, listenerId, requestId);
-    };
-
-    CallbackWrapper.junkyard = [];
-
-    CallbackWrapper.factory = function (messageManager, channelName,
-					listenerId, requestId) {
-	let wrapper = CallbackWrapper.junkyard.pop();
-	if (wrapper) {
-            wrapper.init(messageManager, channelName, listenerId, requestId);
-            return wrapper;
-	}
-	
-	return new CallbackWrapper(messageManager, channelName,
-				   listenerId, requestId);
-    };
-
-    CallbackWrapper.prototype.init = function (messageManager, channelName,
-					       listenerId, requestId) {
-	this.messageManager = messageManager;
-	this.channelName = channelName;
-	this.listenerId = listenerId;
-	this.requestId = requestId;
-    };
-
-    CallbackWrapper.prototype.proxy = function (response) {
-	let message = JSON.stringify({
-            requestId: this.requestId,
-            channelName: this.channelName,
-            msg: response !== undefined ? response : null
-	});
-
-	if (this.messageManager.sendAsyncMessage) {
-            this.messageManager.sendAsyncMessage(this.listenerId, message);
-	} else {
-            this.messageManager.broadcastAsyncMessage(this.listenerId, message);
-	}
-
-	// Mark for reuse
-	this.messageManager = this.channelName =
-	    this.requestId = this.listenerId = null;
-	
-	CallbackWrapper.junkyard.push(this);
-    };
-
     let httpRequestHeadersFactory = function (channel) {
 	let entry = httpRequestHeadersFactory.junkyard.pop();
 	if (entry) {
diff --git a/js/vapi-messaging.js b/js/vapi-messaging.js
index abed913..b00c054 100644
--- a/js/vapi-messaging.js
+++ b/js/vapi-messaging.js
@@ -32,6 +32,8 @@
 (function () {
     const {classes: Cc, interfaces: Ci, utils: Cu} = Components;
     const {Services} = Cu.import('resource://gre/modules/Services.jsm', null);
+    const {CallbackWrapper} =
+	  Cu.import('chrome://ematrix/content/CallbackWrapper.jsm', null);
 
     let vAPI = self.vAPI; // Guaranteed to be initialized by vapi-background.js