Bug 1040336 - Uplift Add-on SDK to Firefox r=me

addon-sdk/source/lib/dev/frame-script.js

@@ -0,0 +1,115 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+(function({content, sendSyncMessage, addMessageListener, sendAsyncMessage}) {
+
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+const observerService = Cc["@mozilla.org/observer-service;1"]
+                        .getService(Ci.nsIObserverService);
+
+const channels = new Map();
+const handles = new WeakMap();
+
+// Takes remote port handle and creates a local one.
+// also set's up a messaging channel between them.
+// This is temporary workaround until Bug 914974 is fixed
+// and port can be transfered through message manager.
+const demarshal = (handle) => {
+  if (handle.type === "MessagePort") {
+    if (!channels.has(handle.id)) {
+      const channel = new content.MessageChannel();
+      channels.set(handle.id, channel);
+      handles.set(channel.port1, handle);
+      channel.port1.onmessage = onOutPort;
+    }
+    return channels.get(handle.id).port2;
+  }
+  return null;
+};
+
+const onOutPort = event => {
+  const handle = handles.get(event.target);
+  sendAsyncMessage("sdk/port/message", {
+    port: handle,
+    message: event.data
+  });
+};
+
+const onInPort = ({data}) => {
+  const channel = channels.get(data.port.id);
+  if (channel)
+    channel.port1.postMessage(data.message);
+};
+
+const onOutEvent = event =>
+  sendSyncMessage("sdk/event/" + event.type,
+                  { type: event.type,
+                    data: event.data });
+
+const onInMessage = (message) => {
+  const {type, data, origin, bubbles, cancelable, ports} = message.data;
+
+  const event = new content.MessageEvent(type, {
+    bubbles: bubbles,
+    cancelable: cancelable,
+    data: data,
+    origin: origin,
+    target: content,
+    source: content,
+    ports: ports.map(demarshal)
+  });
+  content.dispatchEvent(event);
+};
+
+const onReady = event => {
+  channels.clear();
+};
+
+addMessageListener("sdk/event/message", onInMessage);
+addMessageListener("sdk/port/message", onInPort);
+
+const observer = {
+  observe: (document, topic, data) => {
+    // When frame associated with message manager is removed from document `docShell`
+    // is set to `null` but observer is still kept alive. At this point accesing
+    // `content.document` throws "can't access dead object" exceptions. In order to
+    // avoid leaking observer and logged errors observer is going to be removed when
+    // `docShell` is set to `null`.
+    if (!docShell) {
+      observerService.removeObserver(observer, topic);
+    }
+    else if (document === content.document) {
+      if (topic === "content-document-interactive") {
+        sendAsyncMessage("sdk/event/ready", {
+          type: "ready",
+          readyState: document.readyState,
+          uri: document.documentURI
+        });
+      }
+      if (topic === "content-document-loaded") {
+        sendAsyncMessage("sdk/event/load", {
+          type: "load",
+          readyState: document.readyState,
+          uri: document.documentURI
+        });
+      }
+      if (topic === "content-page-hidden") {
+        channels.clear();
+        sendAsyncMessage("sdk/event/unload", {
+          type: "unload",
+          readyState: "uninitialized",
+          uri: document.documentURI
+        });
+      }
+    }
+  }
+};
+
+observerService.addObserver(observer, "content-document-interactive", false);
+observerService.addObserver(observer, "content-document-loaded", false);
+observerService.addObserver(observer, "content-page-hidden", false);
+
+})(this);