code review: spin off init-only code from frameScript into its own init-time frame script

platform/firefox/frameModule.js

@@ -471,30 +471,18 @@ var contentObserver = {
 
 /******************************************************************************/
 
-const locationChangedMessageName = hostName + ':locationChanged';
+var LocationChangeListener = function(docShell, webProgress) {
-
+    var mm = docShell.QueryInterface(Ci.nsIInterfaceRequestor)
-var LocationChangeListener = function(docShell) {
+                     .getInterface(Ci.nsIContentFrameMessageManager);
-    if ( !docShell ) {
+    if ( !mm || typeof mm.sendAsyncMessage !== 'function' ) {
         return;
     }
-
-    var requestor = docShell.QueryInterface(Ci.nsIInterfaceRequestor);
-    var ds = requestor.getInterface(Ci.nsIWebProgress);
-    if ( !ds ) {
-        return;
-    }
-    var mm = requestor.getInterface(Ci.nsIContentFrameMessageManager);
-    if ( !mm ) {
-        return;
-    }
-    if ( typeof mm.sendAsyncMessage !== 'function' ) {
-        return;
-    }
-    this.docShell = ds;
     this.messageManager = mm;
-    ds.addProgressListener(this, Ci.nsIWebProgress.NOTIFY_LOCATION);
+    webProgress.addProgressListener(this, Ci.nsIWebProgress.NOTIFY_LOCATION);
 };
 
+LocationChangeListener.prototype.messageName = hostName + ':locationChanged';
+
 LocationChangeListener.prototype.QueryInterface = XPCOMUtils.generateQI([
     'nsIWebProgressListener',
     'nsISupportsWeakReference'
@@ -504,7 +492,7 @@ LocationChangeListener.prototype.onLocationChange = function(webProgress, reques
     if ( !webProgress.isTopLevel ) {
         return;
     }
-    this.messageManager.sendAsyncMessage(locationChangedMessageName, {
+    this.messageManager.sendAsyncMessage(this.messageName, {
         url: location.asciiSpec,
         flags: flags
     });

platform/firefox/frameScript.js

@@ -1,7 +1,7 @@
 /*******************************************************************************
 
-    µBlock - a browser extension to block requests.
+    uBlock Origin - a browser extension to block requests.
-    Copyright (C) 2014 The µBlock authors
+    Copyright (C) 2014-2016 The uBlock Origin authors
 
     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
@@ -23,68 +23,44 @@
 
 // https://developer.mozilla.org/en-US/Firefox/Multiprocess_Firefox/Frame_script_environment
 
-(function(context) {
+(function() {
 
-'use strict';
+    'use strict';
 
-/******************************************************************************/
+    if ( !this.docShell ) {
-
-let {contentObserver, LocationChangeListener} = Components.utils.import(
-    Components.stack.filename.replace('Script', 'Module'),
-    null
-);
-
-// https://github.com/gorhill/uBlock/issues/1444
-// Apparently the same context is used for all extensions, hence we must use
-// scoped variables to ensure no collision.
-let locationChangeListener;
-
-let injectContentScripts = function(win) {
-    if ( !win || !win.document ) {
         return;
     }
 
-    contentObserver.observe(win.document);
+    let {LocationChangeListener} = Components.utils.import(
+        Components.stack.filename.replace('Script', 'Module'),
+        null
+    );
 
-    if ( win.frames && win.frames.length ) {
+    // https://github.com/gorhill/uBlock/issues/1444
-        let i = win.frames.length;
+    // Apparently the same context is used for all extensions, hence we must
-        while ( i-- ) {
+    // use scoped variables to ensure no collision.
-            injectContentScripts(win.frames[i]);
+    let locationChangeListener;
+
+    // https://developer.mozilla.org/en-US/Add-ons/Code_snippets/Progress_Listeners
+    // "Note that the browser uses a weak reference to your listener object,
+    // "so make sure to keep an external reference to your object to ensure
+    // "that it stays in memory."
+    // This listener below allows us to keep `locationChangeListener` alive
+    // until we no longer need it.
+    let shutdown = function(ev) {
+        if ( ev.target === this ) {
+            this.removeEventListener('unload', shutdown);
         }
+    };
+    this.addEventListener('unload', shutdown);
+
+    let webProgress = this.docShell
+                          .QueryInterface(Components.interfaces.nsIInterfaceRequestor)
+                          .getInterface(Components.interfaces.nsIWebProgress);
+    if ( webProgress && webProgress.isTopLevel ) {
+        locationChangeListener = new LocationChangeListener(this.docShell, webProgress);
     }
-};
 
-let onLoadCompleted = function() {
+}).call(this);
-    context.removeMessageListener('ublock0-load-completed', onLoadCompleted);
-    injectContentScripts(context.content);
-};
-context.addMessageListener('ublock0-load-completed', onLoadCompleted);
-
-let shutdown = function(ev) {
-    if ( ev.target !== context ) {
-        return;
-    }
-    context.removeMessageListener('ublock0-load-completed', onLoadCompleted);
-    context.removeEventListener('unload', shutdown);
-    locationChangeListener = null;
-    LocationChangeListener = null;
-    contentObserver = null;
-};
-context.addEventListener('unload', shutdown);
-
-if ( context.docShell ) {
-    let Ci = Components.interfaces;
-    let wp = context.docShell.QueryInterface(Ci.nsIInterfaceRequestor)
-                             .getInterface(Ci.nsIWebProgress);
-    let dw = wp.DOMWindow;
-
-    if ( dw === dw.top ) {
-        locationChangeListener = new LocationChangeListener(context.docShell);
-    }
-}
-
-/******************************************************************************/
-
-})(this);
 
 /******************************************************************************/

platform/firefox/frameScript0.js

@@ -0,0 +1,58 @@
+/*******************************************************************************
+
+    uBlock Origin - a browser extension to block requests.
+    Copyright (C) 2014-2016 The uBlock Origin authors
+
+    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://github.com/gorhill/uBlock
+*/
+
+/******************************************************************************/
+
+// https://developer.mozilla.org/en-US/Firefox/Multiprocess_Firefox/Frame_script_environment
+
+(function(context) {
+
+    'use strict';
+
+    if ( !context.content ) {
+        return;
+    }
+
+    let {contentObserver} = Components.utils.import(
+        Components.stack.filename.replace('Script0', 'Module'),
+        null
+    );
+
+    let injectContentScripts = function(win) {
+        if ( !win || !win.document ) {
+            return;
+        }
+
+        contentObserver.observe(win.document);
+
+        if ( win.frames && win.frames.length ) {
+            let i = win.frames.length;
+            while ( i-- ) {
+                injectContentScripts(win.frames[i]);
+            }
+        }
+    };
+
+    injectContentScripts(context.content);
+
+})(this);
+
+/******************************************************************************/

platform/firefox/vapi-background.js

@@ -20,7 +20,7 @@
 */
 
 /* jshint esnext: true, bitwise: false */
-/* global self, Components, punycode, µBlock */
+/* global punycode */
 
 // For background page
 
@@ -3367,16 +3367,21 @@ vAPI.lastError = function() {
 // the web pages before uBlock was ready.
 
 vAPI.onLoadAllCompleted = function() {
+    // TODO: vAPI shouldn't know about uBlock. Just like in uMatrix, uBlock
+    // should collect on its side all the opened tabs whenever it is ready.
     var µb = µBlock;
     var tabId;
     for ( var browser of tabWatcher.browsers() ) {
         tabId = tabWatcher.tabIdFromTarget(browser);
         µb.tabContextManager.commit(tabId, browser.currentURI.asciiSpec);
         µb.bindTabToPageStats(tabId);
-        browser.messageManager.sendAsyncMessage(
-            location.host + '-load-completed'
-        );
     }
+    // Inject special frame script, which sole purpose is to inject
+    // content scripts into *already* opened tabs. This allows to unclutter
+    // the main frame script.
+    vAPI.messaging
+        .globalMessageManager
+        .loadFrameScript(vAPI.getURL('frameScript0.js'), false);
 };
 
 /******************************************************************************/