1 files changed, 242 insertions, 0 deletions
diff --git a/remote/shared/messagehandler/WindowGlobalMessageHandler.sys.mjs b/remote/shared/messagehandler/WindowGlobalMessageHandler.sys.mjs
new file mode 100644
index 0000000000..1e0164cf44
--- /dev/null
+++ b/remote/shared/messagehandler/WindowGlobalMessageHandler.sys.mjs
@@ -0,0 +1,242 @@
+/* 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 {
+  ContextDescriptorType,
+  MessageHandler,
+} from "chrome://remote/content/shared/messagehandler/MessageHandler.sys.mjs";
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  error: "chrome://remote/content/shared/webdriver/Errors.sys.mjs",
+  getMessageHandlerFrameChildActor:
+    "chrome://remote/content/shared/messagehandler/transports/js-window-actors/MessageHandlerFrameChild.sys.mjs",
+  RootMessageHandler:
+    "chrome://remote/content/shared/messagehandler/RootMessageHandler.sys.mjs",
+  WindowRealm: "chrome://remote/content/shared/Realm.sys.mjs",
+});
+
+/**
+ * A WindowGlobalMessageHandler is dedicated to debugging a single window
+ * global. It follows the lifecycle of the corresponding window global and will
+ * therefore not survive any navigation. This MessageHandler cannot forward
+ * commands further to other MessageHandlers and represents a leaf node in a
+ * MessageHandler network.
+ */
+export class WindowGlobalMessageHandler extends MessageHandler {
+  #innerWindowId;
+  #realms;
+
+  constructor() {
+    super(...arguments);
+
+    this.#innerWindowId = this.context.window.windowGlobalChild.innerWindowId;
+
+    // Maps sandbox names to instances of window realms,
+    // the default realm is mapped to an empty string sandbox name.
+    this.#realms = new Map([["", new lazy.WindowRealm(this.context.window)]]);
+  }
+
+  destroy() {
+    for (const realm of this.#realms.values()) {
+      realm.destroy();
+    }
+    this.#realms = null;
+
+    super.destroy();
+  }
+
+  /**
+   * Returns the WindowGlobalMessageHandler module path.
+   *
+   * @returns {string}
+   */
+  static get modulePath() {
+    return "windowglobal";
+  }
+
+  /**
+   * Returns the WindowGlobalMessageHandler type.
+   *
+   * @returns {string}
+   */
+  static get type() {
+    return "WINDOW_GLOBAL";
+  }
+
+  /**
+   * For WINDOW_GLOBAL MessageHandlers, `context` is a BrowsingContext,
+   * and BrowsingContext.id can be used as the context id.
+   *
+   * @param {BrowsingContext} context
+   *     WindowGlobalMessageHandler contexts are expected to be
+   *     BrowsingContexts.
+   * @returns {string}
+   *     The browsing context id.
+   */
+  static getIdFromContext(context) {
+    return context.id;
+  }
+
+  get innerWindowId() {
+    return this.#innerWindowId;
+  }
+
+  get realms() {
+    return this.#realms;
+  }
+
+  get window() {
+    return this.context.window;
+  }
+
+  #getRealmFromSandboxName(sandboxName = null) {
+    if (sandboxName === null || sandboxName === "") {
+      return this.#realms.get("");
+    }
+
+    if (this.#realms.has(sandboxName)) {
+      return this.#realms.get(sandboxName);
+    }
+
+    const realm = new lazy.WindowRealm(this.context.window, {
+      sandboxName,
+    });
+
+    this.#realms.set(sandboxName, realm);
+
+    return realm;
+  }
+
+  async applyInitialSessionDataItems(sessionDataItems) {
+    if (!Array.isArray(sessionDataItems)) {
+      return;
+    }
+
+    const destination = {
+      type: WindowGlobalMessageHandler.type,
+    };
+
+    // Create a Map with the structure moduleName -> category -> relevant session data items.
+    const structuredUpdates = new Map();
+    for (const sessionDataItem of sessionDataItems) {
+      const { category, contextDescriptor, moduleName } = sessionDataItem;
+
+      if (!this.matchesContext(contextDescriptor)) {
+        continue;
+      }
+      if (!structuredUpdates.has(moduleName)) {
+        // Skip session data item if the module is not present
+        // for the destination.
+        if (!this.moduleCache.hasModuleClass(moduleName, destination)) {
+          continue;
+        }
+        structuredUpdates.set(moduleName, new Map());
+      }
+
+      if (!structuredUpdates.get(moduleName).has(category)) {
+        structuredUpdates.get(moduleName).set(category, new Set());
+      }
+
+      structuredUpdates.get(moduleName).get(category).add(sessionDataItem);
+    }
+
+    const sessionDataPromises = [];
+
+    for (const [moduleName, categories] of structuredUpdates.entries()) {
+      for (const [category, relevantSessionData] of categories.entries()) {
+        sessionDataPromises.push(
+          this.handleCommand({
+            moduleName,
+            commandName: "_applySessionData",
+            params: {
+              category,
+              initial: true,
+              sessionData: Array.from(relevantSessionData),
+            },
+            destination,
+          })
+        );
+      }
+    }
+
+    await Promise.all(sessionDataPromises);
+
+    // With the session data applied the handler is now ready to be used.
+    this.emitEvent("window-global-handler-created", {
+      contextId: this.contextId,
+      innerWindowId: this.#innerWindowId,
+    });
+  }
+
+  forwardCommand(command) {
+    switch (command.destination.type) {
+      case lazy.RootMessageHandler.type:
+        return lazy
+          .getMessageHandlerFrameChildActor(this)
+          .sendCommand(command, this.sessionId);
+      default:
+        throw new Error(
+          `Cannot forward command to "${command.destination.type}" from "${this.constructor.type}".`
+        );
+    }
+  }
+
+  /**
+   * If <var>realmId</var> is null or not provided get the realm for
+   * a given <var>sandboxName</var>, otherwise find the realm
+   * in the cache with the realm id equal given <var>realmId</var>.
+   *
+   * @param {object} options
+   * @param {string|null=} options.realmId
+   *     The realm id.
+   * @param {string=} options.sandboxName
+   *     The name of sandbox
+   *
+   * @returns {Realm}
+   *     The realm object.
+   */
+  getRealm(options = {}) {
+    const { realmId = null, sandboxName } = options;
+    if (realmId === null) {
+      return this.#getRealmFromSandboxName(sandboxName);
+    }
+
+    const realm = Array.from(this.#realms.values()).find(
+      realm => realm.id === realmId
+    );
+
+    if (realm) {
+      return realm;
+    }
+
+    throw new lazy.error.NoSuchFrameError(`Realm with id ${realmId} not found`);
+  }
+
+  matchesContext(contextDescriptor) {
+    return (
+      contextDescriptor.type === ContextDescriptorType.All ||
+      (contextDescriptor.type === ContextDescriptorType.TopBrowsingContext &&
+        contextDescriptor.id === this.context.browserId)
+    );
+  }
+
+  /**
+   * Send a command to the root MessageHandler.
+   *
+   * @param {Command} command
+   *     The command to send to the root MessageHandler.
+   * @returns {Promise}
+   *     A promise which resolves with the return value of the command.
+   */
+  sendRootCommand(command) {
+    return this.handleCommand({
+      ...command,
+      destination: {
+        type: lazy.RootMessageHandler.type,
+      },
+    });
+  }
+}