1 files changed, 148 insertions, 0 deletions
diff --git a/remote/cdp/sessions/TabSession.sys.mjs b/remote/cdp/sessions/TabSession.sys.mjs
new file mode 100644
index 0000000000..8c8b5f585e
--- /dev/null
+++ b/remote/cdp/sessions/TabSession.sys.mjs
@@ -0,0 +1,148 @@
+/* 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 { Session } from "chrome://remote/content/cdp/sessions/Session.sys.mjs";
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  Log: "chrome://remote/content/shared/Log.sys.mjs",
+});
+
+ChromeUtils.defineLazyGetter(lazy, "logger", () =>
+  lazy.Log.get(lazy.Log.TYPES.CDP)
+);
+
+/**
+ * A session to communicate with a given tab
+ */
+export class TabSession extends Session {
+  /**
+   * @param {Connection} connection
+   *        The connection used to communicate with the server.
+   * @param {TabTarget} target
+   *        The tab target to which this session communicates with.
+   * @param {number=} id
+   *        If this session isn't the default one used for the HTTP endpoint we
+   *        connected to, the session requires an id to distinguish it from the default
+   *        one. This id is used to filter our request, responses and events between
+   *        all active sessions.
+   *        For now, this is only passed by `Target.attachToTarget()`.
+   *        Otherwise it will be undefined when you are connecting directly to
+   *        a given Tab. i.e. connect directly to the WebSocket URL provided by
+   *        /json/list HTTP endpoint.
+   */
+  constructor(connection, target, id) {
+    super(connection, target, id);
+
+    // Request id => { resolve, reject }
+    this.requestPromises = new Map();
+
+    this.registerFramescript(this.mm);
+
+    this.target.browser.addEventListener("XULFrameLoaderCreated", this);
+  }
+
+  destructor() {
+    super.destructor();
+
+    this.requestPromises.clear();
+
+    this.target.browser.removeEventListener("XULFrameLoaderCreated", this);
+
+    // this.mm might be null if the browser of the TabTarget was already closed.
+    // See Bug 1747301.
+    this.mm?.sendAsyncMessage("remote:destroy", {
+      browsingContextId: this.browsingContext.id,
+    });
+
+    this.mm?.removeMessageListener("remote:event", this);
+    this.mm?.removeMessageListener("remote:result", this);
+    this.mm?.removeMessageListener("remote:error", this);
+  }
+
+  execute(id, domain, command, params) {
+    // Check if the domain and command is implemented in the parent
+    // and execute it there. Otherwise forward the command to the content process
+    // in order to try to execute it in the content process.
+    if (this.domains.domainSupportsMethod(domain, command)) {
+      return super.execute(id, domain, command, params);
+    }
+    return this.executeInChild(id, domain, command, params);
+  }
+
+  executeInChild(id, domain, command, params) {
+    return new Promise((resolve, reject) => {
+      // Save the promise's resolution and rejection handler in order to later
+      // resolve this promise once we receive the reply back from the content process.
+      this.requestPromises.set(id, { resolve, reject });
+
+      this.mm.sendAsyncMessage("remote:request", {
+        browsingContextId: this.browsingContext.id,
+        request: { id, domain, command, params },
+      });
+    });
+  }
+
+  get mm() {
+    return this.target.mm;
+  }
+
+  get browsingContext() {
+    return this.target.browsingContext;
+  }
+
+  /**
+   * Register the framescript and listeners for the given message manager.
+   *
+   * @param {MessageManager} messageManager
+   *     The message manager to use.
+   */
+  registerFramescript(messageManager) {
+    messageManager.loadFrameScript(
+      "chrome://remote/content/cdp/sessions/frame-script.js",
+      false
+    );
+
+    messageManager.addMessageListener("remote:event", this);
+    messageManager.addMessageListener("remote:result", this);
+    messageManager.addMessageListener("remote:error", this);
+  }
+
+  // Event handler
+  handleEvent = function ({ target, type }) {
+    switch (type) {
+      case "XULFrameLoaderCreated":
+        if (target === this.target.browser) {
+          lazy.logger.trace("Remoteness change detected");
+          this.registerFramescript(this.mm);
+        }
+        break;
+    }
+  };
+
+  // nsIMessageListener
+
+  receiveMessage({ name, data }) {
+    const { id, result, event, error } = data;
+
+    switch (name) {
+      case "remote:result":
+        const { resolve } = this.requestPromises.get(id);
+        resolve(result);
+        this.requestPromises.delete(id);
+        break;
+
+      case "remote:event":
+        this.connection.sendEvent(event.eventName, event.params, this.id);
+        break;
+
+      case "remote:error":
+        const { reject } = this.requestPromises.get(id);
+        reject(error);
+        this.requestPromises.delete(id);
+        break;
+    }
+  }
+}