Generalized frame connections (#654)

* Create FrameClient and FrameEndpoint

* Use new Frame* classes for Popup=>frame connection

* Update api.sendMessageToFrame and api.broadcastTab to include the sender's frameId

* Update FrameClient to store the frame's frameId

1 files changed, 65 insertions, 0 deletions

diff --git a/ext/mixed/js/frame-endpoint.js b/ext/mixed/js/frame-endpoint.js
new file mode 100644
index 00000000..1cd25bb5
--- /dev/null
+++ b/ext/mixed/js/frame-endpoint.js
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2020  Yomichan Authors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/* global
+ * api
+ */
+
+class FrameEndpoint {
+    constructor() {
+        this._secret = yomichan.generateId(16);
+        this._token = null;
+        this._eventListeners = new EventListenerCollection();
+        this._eventListenersSetup = false;
+    }
+
+    signal() {
+        if (!this._eventListenersSetup) {
+            this._eventListeners.addEventListener(window, 'message', this._onMessage.bind(this), false);
+            this._eventListenersSetup = true;
+        }
+        api.broadcastTab('frameEndpointReady', {secret: this._secret});
+    }
+
+    authenticate(message) {
+        return (
+            this._token !== null &&
+            isObject(message) &&
+            this._token === message.token &&
+            this._secret === message.secret
+        );
+    }
+
+    _onMessage(e) {
+        if (this._token !== null) { return; } // Already initialized
+
+        const data = e.data;
+        if (!isObject(data) || data.action !== 'frameEndpointConnect') { return; } // Invalid message
+
+        const params = data.params;
+        if (!isObject(params)) { return; } // Invalid data
+
+        const secret = params.secret;
+        if (secret !== this._secret) { return; } // Invalid authentication
+
+        const {token, hostFrameId} = params;
+        this._token = token;
+
+        this._eventListeners.removeAllEventListeners();
+        api.sendMessageToFrame(hostFrameId, 'frameEndpointConnected', {secret, token});
+    }
+}