1 files changed, 120 insertions, 0 deletions
diff --git a/remote/shared/messagehandler/transports/js-window-actors/MessageHandlerFrameParent.sys.mjs b/remote/shared/messagehandler/transports/js-window-actors/MessageHandlerFrameParent.sys.mjs
new file mode 100644
index 0000000000..f845b2fa01
--- /dev/null
+++ b/remote/shared/messagehandler/transports/js-window-actors/MessageHandlerFrameParent.sys.mjs
@@ -0,0 +1,120 @@
+/* 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/. */
+
+import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  error: "chrome://remote/content/shared/messagehandler/Errors.sys.mjs",
+  RootMessageHandlerRegistry:
+    "chrome://remote/content/shared/messagehandler/RootMessageHandlerRegistry.sys.mjs",
+  WindowGlobalMessageHandler:
+    "chrome://remote/content/shared/messagehandler/WindowGlobalMessageHandler.sys.mjs",
+});
+
+XPCOMUtils.defineLazyGetter(lazy, "WebDriverError", () => {
+  return ChromeUtils.importESModule(
+    "chrome://remote/content/shared/webdriver/Errors.sys.mjs"
+  ).error.WebDriverError;
+});
+
+/**
+ * Parent actor for the MessageHandlerFrame JSWindowActor. The
+ * MessageHandlerFrame actor is used by RootTransport to communicate between
+ * ROOT MessageHandlers and WINDOW_GLOBAL MessageHandlers.
+ */
+export class MessageHandlerFrameParent extends JSWindowActorParent {
+  async receiveMessage(message) {
+    switch (message.name) {
+      case "MessageHandlerFrameChild:sendCommand": {
+        return this.#handleSendCommandMessage(message.data);
+      }
+      case "MessageHandlerFrameChild:messageHandlerEvent": {
+        return this.#handleMessageHandlerEventMessage(message.data);
+      }
+      default:
+        throw new Error("Unsupported message:" + message.name);
+    }
+  }
+
+  /**
+   * Send a command to the corresponding MessageHandlerFrameChild actor via a
+   * JSWindowActor query.
+   *
+   * @param {Command} command
+   *     The command to forward. See type definition in MessageHandler.js
+   * @param {string} sessionId
+   *     ID of the session that sent the command.
+   * @returns {Promise}
+   *     Promise that will resolve with the result of query sent to the
+   *     MessageHandlerFrameChild actor.
+   */
+  async sendCommand(command, sessionId) {
+    const result = await this.sendQuery(
+      "MessageHandlerFrameParent:sendCommand",
+      {
+        command,
+        sessionId,
+      }
+    );
+
+    if (result?.error) {
+      if (result.isMessageHandlerError) {
+        throw lazy.error.MessageHandlerError.fromJSON(result.error);
+      }
+
+      // TODO: Do not assume WebDriver is the session protocol, see Bug 1779026.
+      throw lazy.WebDriverError.fromJSON(result.error);
+    }
+
+    return result;
+  }
+
+  async #handleMessageHandlerEventMessage(messageData) {
+    const { name, contextInfo, data, sessionId } = messageData;
+    const [moduleName] = name.split(".");
+
+    // Re-emit the event on the RootMessageHandler.
+    const messageHandler =
+      lazy.RootMessageHandlerRegistry.getExistingMessageHandler(sessionId);
+    // TODO: getModuleInstance expects a CommandDestination in theory,
+    // but only uses the MessageHandler type in practice, see Bug 1776389.
+    const module = messageHandler.moduleCache.getModuleInstance(moduleName, {
+      type: lazy.WindowGlobalMessageHandler.type,
+    });
+    let eventPayload = data;
+
+    // Modify an event payload if there is a special method in the targeted module.
+    // If present it can be found in windowglobal-in-root module.
+    if (module?.interceptEvent) {
+      eventPayload = await module.interceptEvent(name, data);
+
+      // Make sure that an event payload is returned.
+      if (!eventPayload) {
+        throw new Error(
+          `${moduleName}.interceptEvent doesn't return the event payload`
+        );
+      }
+    }
+    messageHandler.emitEvent(name, eventPayload, contextInfo);
+  }
+
+  async #handleSendCommandMessage(messageData) {
+    const { sessionId, command } = messageData;
+    const messageHandler =
+      lazy.RootMessageHandlerRegistry.getExistingMessageHandler(sessionId);
+    try {
+      return await messageHandler.handleCommand(command);
+    } catch (e) {
+      if (e?.isRemoteError) {
+        return {
+          error: e.toJSON(),
+          isMessageHandlerError: e.isMessageHandlerError,
+        };
+      }
+      throw e;
+    }
+  }
+}