1 files changed, 171 insertions, 0 deletions
diff --git a/devtools/server/connectors/frame-connector.js b/devtools/server/connectors/frame-connector.js
new file mode 100644
index 0000000000..789d405d90
--- /dev/null
+++ b/devtools/server/connectors/frame-connector.js
@@ -0,0 +1,171 @@
+/* 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";
+
+var DevToolsUtils = require("devtools/shared/DevToolsUtils");
+var { dumpn } = DevToolsUtils;
+
+loader.lazyRequireGetter(
+  this,
+  "DevToolsServer",
+  "resource://devtools/server/devtools-server.js",
+  true
+);
+loader.lazyRequireGetter(
+  this,
+  "ChildDebuggerTransport",
+  "resource://devtools/shared/transport/child-transport.js",
+  true
+);
+
+loader.lazyRequireGetter(
+  this,
+  "EventEmitter",
+  "resource://devtools/shared/event-emitter.js"
+);
+
+/**
+ * Start a DevTools server in a remote frame's process and add it as a child server for
+ * an active connection.
+ *
+ * @param object connection
+ *        The devtools server connection to use.
+ * @param Element frame
+ *        The frame element with remote content to connect to.
+ * @param function [onDestroy]
+ *        Optional function to invoke when the child process closes or the connection
+ *        shuts down. (Need to forget about the related target actor.)
+ * @return object
+ *         A promise object that is resolved once the connection is established.
+ */
+function connectToFrame(
+  connection,
+  frame,
+  onDestroy,
+  { addonId, addonBrowsingContextGroupId } = {}
+) {
+  return new Promise(resolve => {
+    // Get messageManager from XUL browser (which might be a specialized tunnel for RDM)
+    // or else fallback to asking the frameLoader itself.
+    const mm = frame.messageManager || frame.frameLoader.messageManager;
+    mm.loadFrameScript("resource://devtools/server/startup/frame.js", false);
+
+    const trackMessageManager = () => {
+      if (!actor) {
+        mm.addMessageListener("debug:actor", onActorCreated);
+      }
+    };
+
+    const untrackMessageManager = () => {
+      if (!actor) {
+        mm.removeMessageListener("debug:actor", onActorCreated);
+      }
+    };
+
+    let actor, childTransport;
+    const prefix = connection.allocID("child");
+    // Compute the same prefix that's used by DevToolsServerConnection
+    const connPrefix = prefix + "/";
+
+    const onActorCreated = DevToolsUtils.makeInfallible(function (msg) {
+      if (msg.json.prefix != prefix) {
+        return;
+      }
+      mm.removeMessageListener("debug:actor", onActorCreated);
+
+      // Pipe Debugger message from/to parent/child via the message manager
+      childTransport = new ChildDebuggerTransport(mm, prefix);
+      childTransport.hooks = {
+        // Pipe all the messages from content process actors back to the client
+        // through the parent process connection.
+        onPacket: connection.send.bind(connection),
+      };
+      childTransport.ready();
+
+      connection.setForwarding(prefix, childTransport);
+
+      dumpn(`Start forwarding for frame with prefix ${prefix}`);
+
+      actor = msg.json.actor;
+      resolve(actor);
+    });
+
+    const destroy = DevToolsUtils.makeInfallible(function () {
+      EventEmitter.off(connection, "closed", destroy);
+      Services.obs.removeObserver(
+        onMessageManagerClose,
+        "message-manager-close"
+      );
+
+      // TODO: Remove this deprecated path once it's no longer needed by add-ons.
+      DevToolsServer.emit("disconnected-from-child:" + connPrefix, {
+        mm,
+        prefix: connPrefix,
+      });
+
+      if (actor) {
+        actor = null;
+      }
+
+      // Notify the tab descriptor about the destruction before the call to
+      // `cancelForwarding`, so that we notify about the target destruction
+      // *before* we purge all request for this prefix.
+      // When we purge the requests, we also destroy all related fronts,
+      // including the target front. This clears all event listeners
+      // and ultimately prevent target-destroyed from firing.
+      if (onDestroy) {
+        onDestroy(mm);
+      }
+
+      if (childTransport) {
+        // If we have a child transport, the actor has already
+        // been created. We need to stop using this message manager.
+        childTransport.close();
+        childTransport = null;
+        connection.cancelForwarding(prefix);
+
+        // ... and notify the child process to clean the target-scoped actors.
+        try {
+          // Bug 1169643: Ignore any exception as the child process
+          // may already be destroyed by now.
+          mm.sendAsyncMessage("debug:disconnect", { prefix });
+        } catch (e) {
+          // Nothing to do
+        }
+      } else {
+        // Otherwise, the frame has been closed before the actor
+        // had a chance to be created, so we are not able to create
+        // the actor.
+        resolve(null);
+      }
+
+      // Cleanup all listeners
+      untrackMessageManager();
+    });
+
+    // Listen for various messages and frame events
+    trackMessageManager();
+
+    // Listen for app process exit
+    const onMessageManagerClose = function (subject, topic, data) {
+      if (subject == mm) {
+        destroy();
+      }
+    };
+    Services.obs.addObserver(onMessageManagerClose, "message-manager-close");
+
+    // Listen for connection close to cleanup things
+    // when user unplug the device or we lose the connection somehow.
+    EventEmitter.on(connection, "closed", destroy);
+
+    mm.sendAsyncMessage("debug:connect", {
+      prefix,
+      addonId,
+      addonBrowsingContextGroupId,
+    });
+  });
+}
+
+exports.connectToFrame = connectToFrame;