various minor code review

src/js/contentscript.js

@@ -923,15 +923,15 @@ vAPI.executionCost.start();
     // Extract and return the staged nodes which (may) match the selectors.
 
     var selectNodes = function(selector) {
-        var targetNodes = [];
-        var i = contextNodes.length;
-        var node, nodeList, j;
-        var doc = document;
+        var stagedNodes = contextNodes,
+            i = stagedNodes.length;
+        if ( i === 1 && stagedNodes[0] === document.documentElement ) {
+            return document.querySelectorAll(selector);
+        }
+        var targetNodes = [],
+            node, nodeList, j;
         while ( i-- ) {
-            node = contextNodes[i];
-            if ( node === doc ) {
-                return doc.querySelectorAll(selector);
-            }
+            node = stagedNodes[i];
             targetNodes.push(node);
             nodeList = node.querySelectorAll(selector);
             j = nodeList.length;
@@ -988,29 +988,31 @@ vAPI.executionCost.start();
     // - [href^="http"]
 
     var processHighMediumGenerics = function(generics) {
-        var doc = document;
-        var i = contextNodes.length;
-        var aa = [ null ];
-        var node, nodes;
+        var stagedNodes = contextNodes,
+            i = stagedNodes.length;
+        if ( i === 1 && stagedNodes[0] === document.documentElement ) {
+            processHighMediumGenericsForNodes(document.links, generics);
+            return;
+        }
+        var aa = [ null ],
+            node, nodes;
         while ( i-- ) {
-            node = contextNodes[i];
+            node = stagedNodes[i];
             if ( node.localName === 'a' ) {
                 aa[0] = node;
                 processHighMediumGenericsForNodes(aa, generics);
             }
             nodes = node.getElementsByTagName('a');
-            if ( nodes.length === 0 ) { continue; }
-            processHighMediumGenericsForNodes(nodes, generics);
-            if ( node === doc ) {
-                break;
+            if ( nodes.length !== 0 ) {
+                processHighMediumGenericsForNodes(nodes, generics);
             }
         }
     };
 
     var processHighMediumGenericsForNodes = function(nodes, generics) {
-        var i = nodes.length;
-        var node, href, pos, hash, selectors, j, selector;
-        var aa = [ '' ];
+        var i = nodes.length,
+            node, href, pos, hash, selectors, j, selector,
+            aa = [ '' ];
         while ( i-- ) {
             node = nodes[i];
             href = node.getAttribute('href');
@@ -1139,7 +1141,12 @@ vAPI.executionCost.start();
 
     // Start cosmetic filtering.
 
-    classesAndIdsFromNodeList(document.querySelectorAll('[class],[id]'));
+    var allElems = document.all;
+    classesAndIdsFromNodeList(
+        allElems instanceof Object ?
+            allElems :
+            document.querySelectorAll('[class],[id]')
+    );
     retrieveGenericSelectors();
 
     //console.debug('%f: uBlock: survey time', timer.now() - tStart);

src/js/messaging.js

@@ -503,6 +503,8 @@ var filterRequests = function(pageStore, details) {
         }
         request.collapse = true;
     }
+
+    context.dispose();
     return requests;
 };
 

src/js/pagestore.js

@@ -19,6 +19,8 @@
     Home: https://github.com/gorhill/uBlock
 */
 
+'use strict';
+
 /*******************************************************************************
 
 A PageRequestStore object is used to store net requests in two ways:
@@ -33,8 +35,6 @@ To create a log of net requests
 
 µBlock.PageStore = (function() {
 
-'use strict';
-
 /******************************************************************************/
 
 var µb = µBlock;
@@ -428,14 +428,14 @@ PageStore.prototype.setFrame = function(frameId, frameURL) {
 /******************************************************************************/
 
 PageStore.prototype.createContextFromPage = function() {
-    var context = new µb.tabContextManager.createContext(this.tabId);
+    var context = µb.tabContextManager.createContext(this.tabId);
     context.pageHostname = context.rootHostname;
     context.pageDomain = context.rootDomain;
     return context;
 };
 
 PageStore.prototype.createContextFromFrameId = function(frameId) {
-    var context = new µb.tabContextManager.createContext(this.tabId);
+    var context = µb.tabContextManager.createContext(this.tabId);
     var frameStore = this.frames[frameId];
     if ( frameStore ) {
         context.pageHostname = frameStore.pageHostname;
@@ -448,7 +448,7 @@ PageStore.prototype.createContextFromFrameId = function(frameId) {
 };
 
 PageStore.prototype.createContextFromFrameHostname = function(frameHostname) {
-    var context = new µb.tabContextManager.createContext(this.tabId);
+    var context = µb.tabContextManager.createContext(this.tabId);
     context.pageHostname = frameHostname;
     context.pageDomain = µb.URI.domainFromHostname(frameHostname) || frameHostname;
     return context;

src/js/tab.js

@@ -405,7 +405,11 @@ housekeep itself.
     })();
 
     // Context object, typically to be used to feed filtering engines.
+    var contextJunkyard = [];
     var Context = function(tabId) {
+        this.init(tabId);
+    };
+    Context.prototype.init = function(tabId) {
         var tabContext = lookup(tabId);
         this.rootHostname = tabContext.rootHostname;
         this.rootDomain = tabContext.rootDomain;
@@ -414,9 +418,16 @@ housekeep itself.
         this.requestURL =
         this.requestHostname =
         this.requestDomain = '';
+        return this;
+    };
+    Context.prototype.dispose = function() {
+        contextJunkyard.push(this);
     };
 
     var createContext = function(tabId) {
+        if ( contextJunkyard.length ) {
+            return contextJunkyard.pop().init(tabId);
+        }
         return new Context(tabId);
     };
 

src/js/traffic.js

@@ -19,7 +19,7 @@
     Home: https://github.com/gorhill/uBlock
 */
 
-/* global µBlock, vAPI */
+'use strict';
 
 /******************************************************************************/
 
@@ -27,8 +27,6 @@
 
 µBlock.webRequest = (function() {
 
-'use strict';
-
 /******************************************************************************/
 
 var exports = {};
@@ -115,6 +113,7 @@ var onBeforeRequest = function(details) {
         if ( frameId > 0 && isFrame ) {
             pageStore.setFrame(frameId, requestURL);
         }
+        requestContext.dispose();
         return;
     }
 
@@ -141,9 +140,11 @@ var onBeforeRequest = function(details) {
                 requestContext.pageHostname
             );
         }
+        requestContext.dispose();
         return { redirectUrl: url };
     }
 
+    requestContext.dispose();
     return { cancel: true };
 };
 
@@ -306,6 +307,7 @@ var onBeforeBeacon = function(details) {
             context.rootHostname
         );
     }
+    context.dispose();
     if ( result !== '' ) {
         return { cancel: true };
     }
@@ -351,6 +353,8 @@ var onBeforeBehindTheSceneRequest = function(details) {
         );
     }
 
+    context.dispose();
+
     // Not blocked
     if ( µb.isAllowResult(result) ) {
         return;
@@ -425,6 +429,8 @@ var onRootFrameHeadersReceived = function(details) {
         );
     }
 
+    context.dispose();
+
     // Don't block
     if ( µb.isAllowResult(result) ) {
         return;
@@ -471,6 +477,8 @@ var onFrameHeadersReceived = function(details) {
         );
     }
 
+    context.dispose();
+
     // Don't block
     if ( µb.isAllowResult(result) ) {
         return;