1 files changed, 319 insertions, 0 deletions
diff --git a/mobile/android/modules/geckoview/Messaging.sys.mjs b/mobile/android/modules/geckoview/Messaging.sys.mjs
new file mode 100644
index 0000000000..e67161fede
--- /dev/null
+++ b/mobile/android/modules/geckoview/Messaging.sys.mjs
@@ -0,0 +1,319 @@
+/* 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/. */
+
+const IS_PARENT_PROCESS =
+  Services.appinfo.processType == Services.appinfo.PROCESS_TYPE_DEFAULT;
+
+class ChildActorDispatcher {
+  constructor(actor) {
+    this._actor = actor;
+  }
+
+  // TODO: Bug 1658980
+  registerListener(aListener, aEvents) {
+    throw new Error("Cannot registerListener in child actor");
+  }
+  unregisterListener(aListener, aEvents) {
+    throw new Error("Cannot registerListener in child actor");
+  }
+
+  /**
+   * Sends a request to Java.
+   *
+   * @param aMsg      Message to send; must be an object with a "type" property
+   */
+  sendRequest(aMsg) {
+    this._actor.sendAsyncMessage("DispatcherMessage", aMsg);
+  }
+
+  /**
+   * Sends a request to Java, returning a Promise that resolves to the response.
+   *
+   * @param aMsg Message to send; must be an object with a "type" property
+   * @return A Promise resolving to the response
+   */
+  sendRequestForResult(aMsg) {
+    return this._actor.sendQuery("DispatcherQuery", aMsg);
+  }
+}
+
+function DispatcherDelegate(aDispatcher, aMessageManager) {
+  this._dispatcher = aDispatcher;
+  this._messageManager = aMessageManager;
+
+  if (!aDispatcher) {
+    // Child process.
+    // TODO: this doesn't work with Fission, remove this code path once every
+    // consumer has been migrated. Bug 1569360.
+    this._replies = new Map();
+    (aMessageManager || Services.cpmm).addMessageListener(
+      "GeckoView:MessagingReply",
+      this
+    );
+  }
+}
+
+DispatcherDelegate.prototype = {
+  /**
+   * Register a listener to be notified of event(s).
+   *
+   * @param aListener Target listener implementing nsIAndroidEventListener.
+   * @param aEvents   String or array of strings of events to listen to.
+   */
+  registerListener(aListener, aEvents) {
+    if (!this._dispatcher) {
+      throw new Error("Can only listen in parent process");
+    }
+    this._dispatcher.registerListener(aListener, aEvents);
+  },
+
+  /**
+   * Unregister a previously-registered listener.
+   *
+   * @param aListener Registered listener implementing nsIAndroidEventListener.
+   * @param aEvents   String or array of strings of events to stop listening to.
+   */
+  unregisterListener(aListener, aEvents) {
+    if (!this._dispatcher) {
+      throw new Error("Can only listen in parent process");
+    }
+    this._dispatcher.unregisterListener(aListener, aEvents);
+  },
+
+  /**
+   * Dispatch an event to registered listeners for that event, and pass an
+   * optional data object and/or a optional callback interface to the
+   * listeners.
+   *
+   * @param aEvent     Name of event to dispatch.
+   * @param aData      Optional object containing data for the event.
+   * @param aCallback  Optional callback implementing nsIAndroidEventCallback.
+   * @param aFinalizer Optional finalizer implementing nsIAndroidEventFinalizer.
+   */
+  dispatch(aEvent, aData, aCallback, aFinalizer) {
+    if (this._dispatcher) {
+      this._dispatcher.dispatch(aEvent, aData, aCallback, aFinalizer);
+      return;
+    }
+
+    const mm = this._messageManager || Services.cpmm;
+    const forwardData = {
+      global: !this._messageManager,
+      event: aEvent,
+      data: aData,
+    };
+
+    if (aCallback) {
+      const uuid = Services.uuid.generateUUID().toString();
+      this._replies.set(uuid, {
+        callback: aCallback,
+        finalizer: aFinalizer,
+      });
+      forwardData.uuid = uuid;
+    }
+
+    mm.sendAsyncMessage("GeckoView:Messaging", forwardData);
+  },
+
+  /**
+   * Sends a request to Java.
+   *
+   * @param aMsg      Message to send; must be an object with a "type" property
+   * @param aCallback Optional callback implementing nsIAndroidEventCallback.
+   */
+  sendRequest(aMsg, aCallback) {
+    const type = aMsg.type;
+    aMsg.type = undefined;
+    this.dispatch(type, aMsg, aCallback);
+  },
+
+  /**
+   * Sends a request to Java, returning a Promise that resolves to the response.
+   *
+   * @param aMsg Message to send; must be an object with a "type" property
+   * @return A Promise resolving to the response
+   */
+  sendRequestForResult(aMsg) {
+    return new Promise((resolve, reject) => {
+      const type = aMsg.type;
+      aMsg.type = undefined;
+
+      // Manually release the resolve/reject functions after one callback is
+      // received, so the JS GC is not tied up with the Java GC.
+      const onCallback = (callback, ...args) => {
+        if (callback) {
+          callback(...args);
+        }
+        resolve = undefined;
+        reject = undefined;
+      };
+      const callback = {
+        onSuccess: result => onCallback(resolve, result),
+        onError: error => onCallback(reject, error),
+        onFinalize: _ => onCallback(reject),
+      };
+      this.dispatch(type, aMsg, callback, callback);
+    });
+  },
+
+  finalize() {
+    if (!this._replies) {
+      return;
+    }
+    this._replies.forEach(reply => {
+      if (typeof reply.finalizer === "function") {
+        reply.finalizer();
+      } else if (reply.finalizer) {
+        reply.finalizer.onFinalize();
+      }
+    });
+    this._replies.clear();
+  },
+
+  receiveMessage(aMsg) {
+    const { uuid, type } = aMsg.data;
+    const reply = this._replies.get(uuid);
+    if (!reply) {
+      return;
+    }
+
+    if (type === "success") {
+      reply.callback.onSuccess(aMsg.data.response);
+    } else if (type === "error") {
+      reply.callback.onError(aMsg.data.response);
+    } else if (type === "finalize") {
+      if (typeof reply.finalizer === "function") {
+        reply.finalizer();
+      } else if (reply.finalizer) {
+        reply.finalizer.onFinalize();
+      }
+      this._replies.delete(uuid);
+    } else {
+      throw new Error("invalid reply type");
+    }
+  },
+};
+
+export var EventDispatcher = {
+  instance: new DispatcherDelegate(
+    IS_PARENT_PROCESS ? Services.androidBridge : undefined
+  ),
+
+  /**
+   * Return an EventDispatcher instance for a chrome DOM window. In a content
+   * process, return a proxy through the message manager that automatically
+   * forwards events to the main process.
+   *
+   * To force using a message manager proxy (for example in a frame script
+   * environment), call forMessageManager.
+   *
+   * @param aWindow a chrome DOM window.
+   */
+  for(aWindow) {
+    const view =
+      aWindow &&
+      aWindow.arguments &&
+      aWindow.arguments[0] &&
+      aWindow.arguments[0].QueryInterface(Ci.nsIAndroidView);
+
+    if (!view) {
+      const mm = !IS_PARENT_PROCESS && aWindow && aWindow.messageManager;
+      if (!mm) {
+        throw new Error(
+          "window is not a GeckoView-connected window and does" +
+            " not have a message manager"
+        );
+      }
+      return this.forMessageManager(mm);
+    }
+
+    return new DispatcherDelegate(view);
+  },
+
+  /**
+   * Returns a named EventDispatcher, which can communicate with the
+   * corresponding EventDispatcher on the java side.
+   */
+  byName(aName) {
+    if (!IS_PARENT_PROCESS) {
+      return undefined;
+    }
+    const dispatcher = Services.androidBridge.getDispatcherByName(aName);
+    return new DispatcherDelegate(dispatcher);
+  },
+
+  /**
+   * Return an EventDispatcher instance for a message manager associated with a
+   * window.
+   *
+   * @param aWindow a message manager.
+   */
+  forMessageManager(aMessageManager) {
+    return new DispatcherDelegate(null, aMessageManager);
+  },
+
+  /**
+   * Return the EventDispatcher instance associated with an actor.
+   *
+   * @param aActor an actor
+   */
+  forActor(aActor) {
+    return new ChildActorDispatcher(aActor);
+  },
+
+  receiveMessage(aMsg) {
+    // aMsg.data includes keys: global, event, data, uuid
+    let callback;
+    if (aMsg.data.uuid) {
+      const reply = (type, response) => {
+        const mm = aMsg.data.global ? aMsg.target : aMsg.target.messageManager;
+        if (!mm) {
+          if (type === "finalize") {
+            // It's normal for the finalize call to come after the browser has
+            // been destroyed. We can gracefully handle that case despite
+            // having no message manager.
+            return;
+          }
+          throw Error(
+            `No message manager for ${aMsg.data.event}:${type} reply`
+          );
+        }
+        mm.sendAsyncMessage("GeckoView:MessagingReply", {
+          type,
+          response,
+          uuid: aMsg.data.uuid,
+        });
+      };
+      callback = {
+        onSuccess: response => reply("success", response),
+        onError: error => reply("error", error),
+        onFinalize: () => reply("finalize"),
+      };
+    }
+
+    try {
+      if (aMsg.data.global) {
+        this.instance.dispatch(
+          aMsg.data.event,
+          aMsg.data.data,
+          callback,
+          callback
+        );
+        return;
+      }
+
+      const win = aMsg.target.ownerGlobal;
+      const dispatcher = win.WindowEventDispatcher || this.for(win);
+      dispatcher.dispatch(aMsg.data.event, aMsg.data.data, callback, callback);
+    } catch (e) {
+      callback?.onError(`Error getting dispatcher: ${e}`);
+      throw e;
+    }
+  },
+};
+
+if (IS_PARENT_PROCESS) {
+  Services.mm.addMessageListener("GeckoView:Messaging", EventDispatcher);
+  Services.ppmm.addMessageListener("GeckoView:Messaging", EventDispatcher);
+}