Issue 3224 - Unbreak filter assistant

lib/child/contentPolicy.js

Index: lib/child/contentPolicy.js
===================================================================
--- a/lib/child/contentPolicy.js
+++ b/lib/child/contentPolicy.js
@@ -50,16 +50,43 @@ let collapsedClass = null;
 
 /**
  * Maps numerical content type IDs to strings.
  * @type Map.<number,string>
  */
 let types = new Map();
 
 /**
+ * Contains nodes stored by storeNodes() mapped by their IDs.
+ * @type Map.<string,DOMNode[]>
+ */
+let storedNodes = new Map();

[tschuster, 2015/12/01 16:42:40]

So, this is cleaned up by DeleteNodes, which is called when you close the UI,
right? Shouldn't we clean this up when the content navigates in the child? (I
assume we can't leak because of the DeadObjectProxy, but still something to
think about)

[Wladimir Palant, 2015/12/01 19:15:31]

Nodes can be removed without navigating away (yes, we used to have memory leaks
on websites that did this). So cleaning up when the UI is closed isn't optional.
Doing the same when the child navigates away can be done as well - but it would
add complexity and the gain is rather questionable (typically, the page lives
longer than our composer UI).

+
+/**
+ * Process-dependent prefix to be used for unique nodes identifiers returned
+ * by storeNodes().
+ * @type string
+ */
+let nodesIDPrefix = Services.appinfo.processID + " ";
+
+/**
+ * Counter used to generate unique nodes identifiers in storeNodes().
+ * @type number
+ */
+let maxNodesID = 0;
+
+addMessageListener("AdblockPlus:DeleteNodes", onDeleteNodes);
+addMessageListener("AdblockPlus:RefilterNodes", onRefilterNodes);
+
+onShutdown.add(() => {
+  removeMessageListener("AdblockPlus:DeleteNodes", onDeleteNodes);
+  removeMessageListener("AdblockPlus:RefilterNodes", onRefilterNodes);
+});
+
+/**
  * Processes parent's response to the ShouldAllow message.
  * @param {nsIDOMWindow} window window that the request is associated with
  * @param {nsIDOMElement} node  DOM element that the request is associated with
  * @param {Object|undefined} response  object received as response
  * @return {Boolean} false if the request should be blocked
  */
 function processPolicyResponse(window, node, response)
 {
@@ -132,16 +159,73 @@ let shouldAllowAsync = exports.shouldAll
     contentType,
     location,
     frames: getFrames(window),
     isPrivate: isPrivate(window)
   }, response => callback(processPolicyResponse(window, node, response)));
 };
 
 /**
+ * Stores nodes and generates a unique ID for them that can be used for
+ * Policy.refilterNodes() later. It's important that Policy.deleteNodes() is
+ * called later, otherwise the nodes will be leaked.
+ * @param {DOMNode[]} nodes  list of nodes to be stored
+ * @return {string}  unique ID for the nodes
+ */
+let storeNodes = exports.storeNodes = function(nodes)
+{
+  let id = nodesIDPrefix + (++maxNodesID);
+  storedNodes.set(id, nodes);
+  return id;
+};
+
+/**
+ * Called via message whenever Policy.deleteNodes() is called in the parent.
+ */
+function onDeleteNodes(message)
+{
+  storedNodes.delete(message.data);
+}
+
+/**
+ * Called via message whenever Policy.refilterNodes() is called in the parent.
+ */
+function onRefilterNodes(message)
+{
+  let {nodesID, entry} = message.data;
+  let nodes = storedNodes.get(nodesID);
+  if (nodes)
+    for (let node of nodes)
+      if (node.nodeType == Ci.nsIDOMNode.ELEMENT_NODE)
+        Utils.runAsync(refilterNode.bind(this, node, entry));
+}
+
+/**
+ * Re-checks filters on an element.
+ */
+function refilterNode(/**Node*/ node, /**Object*/ entry)
+{
+  let wnd = Utils.getWindow(node);
+  if (!wnd || wnd.closed)
+    return;
+
+  if (entry.type == "OBJECT")
+  {
+    node.removeEventListener("mouseover", objectMouseEventHander, true);
+    node.removeEventListener("mouseout", objectMouseEventHander, true);
+  }
+
+  shouldAllow(wnd, node, entry.type, entry.location, (allow) => {
+    // Force node to be collapsed
+    if (!allow)
+      schedulePostProcess(node)
+  });
+}
+
+/**
  * Actual nsIContentPolicy and nsIChannelEventSink implementation
  * @class
  */
 var PolicyImplementation =
 {
   classDescription: "Adblock Plus content policy",
   classID: Components.ID("cfeaabe6-1dd1-11b2-a0c6-cb5c268894c9"),
   contractID: "@adblockplus.org/abp/policy;1",