Issue 3251 - Add shouldAllowAsync() function for non-urgent policy checks

lib/child/contentPolicy.js

Index: lib/child/contentPolicy.js
===================================================================
--- a/lib/child/contentPolicy.js
+++ b/lib/child/contentPolicy.js
@@ -55,57 +55,71 @@ let collapsedClass = null;
 let types = new Map();
 
 /**
  * Checks whether a request should be allowed, hides it if necessary
  * @param wnd {nsIDOMWindow}
  * @param node {nsIDOMElement}
  * @param contentType {String}
  * @param location {String}
+ * @param [callback] {Function} If present, the request will be sent
+ *                              asynchronously and callback called with the
+ *                              response
  * @return {Boolean} false if the request should be blocked
  */
-function shouldAllow(window, node, contentType, location)
+function shouldAllow(window, node, contentType, location, callback)

[tschuster, 2015/11/12 13:38:13]

This should really be two functions. If you reuse processResponse the
duplication should be small.

[Wladimir Palant, 2015/11/12 15:01:13]

Done.

 {
-  let response = sendSyncMessage("AdblockPlus:ShouldAllow", {
+  function processResponse(response)
+  {
+    if (typeof response == "undefined")
+      return true;
+
+    let {allow, collapse, hits} = response;
+    for (let {frameIndex, contentType, docDomain, thirdParty, location, filter} of hits)
+    {
+      let context = node;
+      if (typeof frameIndex == "number")
+      {
+        context = window;
+        for (let i = 0; i < frameIndex; i++)
+          context = context.parent;
+        context = context.document;
+      }
+      RequestNotifier.addNodeData(context, window.top, contentType, docDomain, thirdParty, location, filter);
+    }
+
+    if (node.nodeType == Ci.nsIDOMNode.ELEMENT_NODE)
+    {
+      // Track mouse events for objects
+      if (allow && contentType == "OBJECT")
+      {
+        node.addEventListener("mouseover", objectMouseEventHander, true);
+        node.addEventListener("mouseout", objectMouseEventHander, true);
+      }
+
+      if (collapse)
+        schedulePostProcess(node);
+    }
+    return allow;
+  }

[Wladimir Palant, 2015/11/04 15:05:22]

The diff is messy but all the code above has merely been moved around.

+
+  let data = {
     contentType: contentType,
     location: location,
     frames: getFrames(window),
     isPrivate: isPrivate(window)
-  });
-  if (typeof response == "undefined")
-    return true;
-
-  let {allow, collapse, hits} = response;
-  for (let {frameIndex, contentType, docDomain, thirdParty, location, filter} of hits)
+  };
+  if (typeof callback == "function")
   {
-    let context = node;
-    if (typeof frameIndex == "number")
-    {
-      context = window;
-      for (let i = 0; i < frameIndex; i++)
-        context = context.parent;
-      context = context.document;
-    }
-    RequestNotifier.addNodeData(context, window.top, contentType, docDomain, thirdParty, location, filter);
+    sendAsyncMessage("AdblockPlus:ShouldAllow", data, (data) => {
+      callback(processResponse(data));
+    });
   }
-
-  if (node.nodeType == Ci.nsIDOMNode.ELEMENT_NODE)
-  {
-    // Track mouse events for objects
-    if (allow && contentType == "OBJECT")
-    {
-      node.addEventListener("mouseover", objectMouseEventHander, true);
-      node.addEventListener("mouseout", objectMouseEventHander, true);
-    }
-
-    if (collapse)
-      schedulePostProcess(node);
-  }
-
-  return allow;
+  else
+    return processResponse(sendSyncMessage("AdblockPlus:ShouldAllow", data));
 }
 
 /**
  * Actual nsIContentPolicy and nsIChannelEventSink implementation
  * @class
  */
 var PolicyImplementation =
 {
@@ -229,17 +243,17 @@ var PolicyImplementation =
   },
 
   //
   // nsIChannelEventSink interface implementation
   //
 
   asyncOnChannelRedirect: function(oldChannel, newChannel, flags, callback)
   {
-    let result = Cr.NS_OK;
+    let async = false;
     try
     {
       // nsILoadInfo.contentPolicyType was introduced in Gecko 35, then
       // renamed to nsILoadInfo.externalContentPolicyType in Gecko 44.
       let loadInfo = oldChannel.loadInfo;
       let contentType = ("externalContentPolicyType" in loadInfo ?
           loadInfo.externalContentPolicyType : loadInfo.contentPolicyType);
       if (!contentType)
@@ -257,27 +271,31 @@ var PolicyImplementation =
           // seen the original channel yet because the redirect happened before
           // the async code in observe() had a chance to run.
           this.observe(wnd, "content-document-global-created", null, oldChannel.URI.spec);
           this.observe(wnd, "content-document-global-created", null, newChannel.URI.spec);
         }
         return;
       }
 
-      if (!shouldAllow(wnd, wnd.document, types.get(contentType), newChannel.URI.spec))
-        result = Cr.NS_BINDING_ABORTED;
+      shouldAllow(wnd, wnd.document, types.get(contentType), newChannel.URI.spec, function(allow)
+      {
+        callback.onRedirectVerifyCallback(allow ? Cr.NS_OK : Cr.NS_BINDING_ABORTED);
+      });
+      async = true;
     }
     catch (e)
     {
       // We shouldn't throw exceptions here - this will prevent the redirect.
       Cu.reportError(e);
     }
     finally
     {
-      callback.onRedirectVerifyCallback(result);
+      if (!async)
+        callback.onRedirectVerifyCallback(Cr.NS_OK);
     }
   },
 
   //
   // nsIFactory interface implementation
   //
 
   createInstance: function(outer, iid)