1 files changed, 406 insertions, 0 deletions
diff --git a/remote/webdriver-bidi/modules/root/session.sys.mjs b/remote/webdriver-bidi/modules/root/session.sys.mjs
new file mode 100644
index 0000000000..281b913f32
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+++ b/remote/webdriver-bidi/modules/root/session.sys.mjs
@@ -0,0 +1,406 @@
+/* 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 { Module } from "chrome://remote/content/shared/messagehandler/Module.sys.mjs";
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  assert: "chrome://remote/content/shared/webdriver/Assert.sys.mjs",
+  ContextDescriptorType:
+    "chrome://remote/content/shared/messagehandler/MessageHandler.sys.mjs",
+  error: "chrome://remote/content/shared/webdriver/Errors.sys.mjs",
+  RootMessageHandler:
+    "chrome://remote/content/shared/messagehandler/RootMessageHandler.sys.mjs",
+  TabManager: "chrome://remote/content/shared/TabManager.sys.mjs",
+});
+
+class SessionModule extends Module {
+  #browsingContextIdEventMap;
+  #globalEventSet;
+
+  constructor(messageHandler) {
+    super(messageHandler);
+
+    // Map with top-level browsing context id keys and values
+    // that are a set of event names for events
+    // that are enabled in the given browsing context.
+    // TODO: Bug 1804417. Use navigable instead of browsing context id.
+    this.#browsingContextIdEventMap = new Map();
+
+    // Set of event names which are strings of the form [moduleName].[eventName]
+    // for events that are enabled for all browsing contexts.
+    // We should only add an actual event listener on the MessageHandler the
+    // first time an event is subscribed to.
+    this.#globalEventSet = new Set();
+  }
+
+  destroy() {
+    this.#browsingContextIdEventMap = null;
+    this.#globalEventSet = null;
+  }
+
+  /**
+   * Commands
+   */
+
+  /**
+   * Enable certain events either globally, or for a list of browsing contexts.
+   *
+   * @params {Object=} params
+   * @params {Array<string>} events
+   *     List of events to subscribe to.
+   * @params {Array<string>=} contexts
+   *     Optional list of top-level browsing context ids
+   *     to subscribe the events for.
+   *
+   * @throws {InvalidArgumentError}
+   *     If <var>events</var> or <var>contexts</var> are not valid types.
+   */
+  async subscribe(params = {}) {
+    const { events, contexts: contextIds = null } = params;
+
+    // Check input types until we run schema validation.
+    lazy.assert.array(events, "events: array value expected");
+    events.forEach(name => {
+      lazy.assert.string(name, `${name}: string value expected`);
+    });
+
+    if (contextIds !== null) {
+      lazy.assert.array(contextIds, "contexts: array value expected");
+      contextIds.forEach(contextId => {
+        lazy.assert.string(contextId, `${contextId}: string value expected`);
+      });
+    }
+
+    const listeners = this.#updateEventMap(events, contextIds, true);
+
+    // TODO: Bug 1801284. Add subscribe priority sorting of subscribeStepEvents (step 4 to 6, and 8).
+
+    // Subscribe to the relevant engine-internal events.
+    await this.messageHandler.eventsDispatcher.update(listeners);
+  }
+
+  /**
+   * Disable certain events either globally, or for a list of browsing contexts.
+   *
+   * @params {Object=} params
+   * @params {Array<string>} events
+   *     List of events to unsubscribe from.
+   * @params {Array<string>=} contexts
+   *     Optional list of top-level browsing context ids
+   *     to unsubscribe the events from.
+   *
+   * @throws {InvalidArgumentError}
+   *     If <var>events</var> or <var>contexts</var> are not valid types.
+   */
+  async unsubscribe(params = {}) {
+    const { events, contexts: contextIds = null } = params;
+
+    // Check input types until we run schema validation.
+    lazy.assert.array(events, "events: array value expected");
+    events.forEach(name => {
+      lazy.assert.string(name, `${name}: string value expected`);
+    });
+    if (contextIds !== null) {
+      lazy.assert.array(contextIds, "contexts: array value expected");
+      contextIds.forEach(contextId => {
+        lazy.assert.string(contextId, `${contextId}: string value expected`);
+      });
+    }
+
+    const listeners = this.#updateEventMap(events, contextIds, false);
+
+    // Unsubscribe from the relevant engine-internal events.
+    await this.messageHandler.eventsDispatcher.update(listeners);
+  }
+
+  #assertModuleSupportsEvent(moduleName, event) {
+    const rootModuleClass = this.#getRootModuleClass(moduleName);
+    if (!rootModuleClass?.supportsEvent(event)) {
+      throw new lazy.error.InvalidArgumentError(
+        `${event} is not a valid event name`
+      );
+    }
+  }
+
+  #getBrowserIdForContextId(contextId) {
+    const context = lazy.TabManager.getBrowsingContextById(contextId);
+    if (!context) {
+      throw new lazy.error.NoSuchFrameError(
+        `Browsing context with id ${contextId} not found`
+      );
+    }
+
+    return context.browserId;
+  }
+
+  #getRootModuleClass(moduleName) {
+    // Modules which support event subscriptions should have a root module
+    // defining supported events.
+    const rootDestination = { type: lazy.RootMessageHandler.type };
+    const moduleClasses = this.messageHandler.getAllModuleClasses(
+      moduleName,
+      rootDestination
+    );
+
+    if (!moduleClasses.length) {
+      throw new lazy.error.InvalidArgumentError(
+        `Module ${moduleName} does not exist`
+      );
+    }
+
+    return moduleClasses[0];
+  }
+
+  #getTopBrowsingContextId(contextId) {
+    const context = lazy.TabManager.getBrowsingContextById(contextId);
+    if (!context) {
+      throw new lazy.error.NoSuchFrameError(
+        `Browsing context with id ${contextId} not found`
+      );
+    }
+    const topContext = context.top;
+    return lazy.TabManager.getIdForBrowsingContext(topContext);
+  }
+
+  /**
+   * Obtain a set of events based on the given event name.
+   *
+   * Could contain a period for a specific event,
+   * or just the module name for all events.
+   *
+   * @param {string} event
+   *     Name of the event to process.
+   *
+   * @returns {Set<string>}
+   *     A Set with the expanded events in the form of `<module>.<event>`.
+   *
+   * @throws {InvalidArgumentError}
+   *     If <var>event</var> does not reference a valid event.
+   */
+  #obtainEvents(event) {
+    const events = new Set();
+
+    // Check if a period is present that splits the event name into the module,
+    // and the actual event. Hereby only care about the first found instance.
+    const index = event.indexOf(".");
+    if (index >= 0) {
+      const [moduleName] = event.split(".");
+      this.#assertModuleSupportsEvent(moduleName, event);
+      events.add(event);
+    } else {
+      // Interpret the name as module, and register all its available events
+      const rootModuleClass = this.#getRootModuleClass(event);
+      const supportedEvents = rootModuleClass?.supportedEvents;
+
+      for (const eventName of supportedEvents) {
+        events.add(eventName);
+      }
+    }
+
+    return events;
+  }
+
+  /**
+   * Obtain a list of event enabled browsing context ids.
+   *
+   * @see https://w3c.github.io/webdriver-bidi/#event-enabled-browsing-contexts
+   *
+   * @param {string} eventName
+   *     The name of the event.
+   *
+   * @return {Set<string>} The set of browsing context.
+   */
+  #obtainEventEnabledBrowsingContextIds(eventName) {
+    const contextIds = new Set();
+    for (const [
+      contextId,
+      events,
+    ] of this.#browsingContextIdEventMap.entries()) {
+      if (events.has(eventName)) {
+        // Check that a browsing context still exists for a given id
+        const context = lazy.TabManager.getBrowsingContextById(contextId);
+        if (context) {
+          contextIds.add(contextId);
+        }
+      }
+    }
+
+    return contextIds;
+  }
+
+  #onMessageHandlerEvent = (name, event) => {
+    this.messageHandler.emitProtocolEvent(name, event);
+  };
+
+  /**
+   * Update global event state for top-level browsing contexts.
+   *
+   * @see https://w3c.github.io/webdriver-bidi/#update-the-event-map
+   *
+   * @param {Array<string>} requestedEventNames
+   *     The list of the event names to run the update for.
+   * @param {Array<string>|null} browsingContextIds
+   *     The list of the browsing context ids to update or null.
+   * @param {boolean} enabled
+   *     True, if events have to be enabled. Otherwise false.
+   *
+   * @return {Array<Subscription>} subscriptions
+   *     The list of information to subscribe/unsubscribe to.
+   *
+   * @throws {InvalidArgumentError}
+   *     If failed unsubscribe from event from <var>requestedEventNames</var> for
+   *     browsing context id from <var>browsingContextIds</var>, if present.
+   */
+  #updateEventMap(requestedEventNames, browsingContextIds, enabled) {
+    const globalEventSet = new Set(this.#globalEventSet);
+    const eventMap = structuredClone(this.#browsingContextIdEventMap);
+
+    const eventNames = new Set();
+
+    requestedEventNames.forEach(name => {
+      this.#obtainEvents(name).forEach(event => eventNames.add(event));
+    });
+    const enabledEvents = new Map();
+    const subscriptions = [];
+
+    if (browsingContextIds === null) {
+      // Subscribe or unsubscribe events for all browsing contexts.
+      if (enabled) {
+        // Subscribe to each event.
+
+        // Get the list of all top level browsing context ids.
+        const allTopBrowsingContextIds = lazy.TabManager.allBrowserUniqueIds;
+
+        for (const eventName of eventNames) {
+          if (!globalEventSet.has(eventName)) {
+            const alreadyEnabledContextIds = this.#obtainEventEnabledBrowsingContextIds(
+              eventName
+            );
+            globalEventSet.add(eventName);
+            for (const contextId of alreadyEnabledContextIds) {
+              eventMap.get(contextId).delete(eventName);
+
+              // Since we're going to subscribe to all top-level
+              // browsing context ids to not have duplicate subscriptions,
+              // we have to unsubscribe from already subscribed.
+              subscriptions.push({
+                event: eventName,
+                contextDescriptor: {
+                  type: lazy.ContextDescriptorType.TopBrowsingContext,
+                  id: this.#getBrowserIdForContextId(contextId),
+                },
+                callback: this.#onMessageHandlerEvent,
+                enable: false,
+              });
+            }
+
+            // Get a list of all top-level browsing context ids
+            // that are not contained in alreadyEnabledContextIds.
+            const newlyEnabledContextIds = allTopBrowsingContextIds.filter(
+              contextId => !alreadyEnabledContextIds.has(contextId)
+            );
+
+            enabledEvents.set(eventName, newlyEnabledContextIds);
+
+            subscriptions.push({
+              event: eventName,
+              contextDescriptor: {
+                type: lazy.ContextDescriptorType.All,
+              },
+              callback: this.#onMessageHandlerEvent,
+              enable: true,
+            });
+          }
+        }
+      } else {
+        // Unsubscribe each event which has a global subscription.
+        for (const eventName of eventNames) {
+          if (globalEventSet.has(eventName)) {
+            globalEventSet.delete(eventName);
+
+            subscriptions.push({
+              event: eventName,
+              contextDescriptor: {
+                type: lazy.ContextDescriptorType.All,
+              },
+              callback: this.#onMessageHandlerEvent,
+              enable: false,
+            });
+          } else {
+            throw new lazy.error.InvalidArgumentError(
+              `Failed to unsubscribe from event ${eventName}`
+            );
+          }
+        }
+      }
+    } else {
+      // Subscribe or unsubscribe events for given list of browsing context ids.
+      const targets = new Map();
+      for (const contextId of browsingContextIds) {
+        const topLevelContextId = this.#getTopBrowsingContextId(contextId);
+        if (!eventMap.has(topLevelContextId)) {
+          eventMap.set(topLevelContextId, new Set());
+        }
+        targets.set(topLevelContextId, eventMap.get(topLevelContextId));
+      }
+
+      for (const eventName of eventNames) {
+        // Do nothing if we want to subscribe,
+        // but the event has already a global subscription.
+        if (enabled && this.#globalEventSet.has(eventName)) {
+          continue;
+        }
+        for (const [contextId, target] of targets.entries()) {
+          // Subscribe if an event doesn't have a subscription for a specific context id.
+          if (enabled && !target.has(eventName)) {
+            target.add(eventName);
+            if (!enabledEvents.has(eventName)) {
+              enabledEvents.set(eventName, new Set());
+            }
+            enabledEvents.get(eventName).add(contextId);
+
+            subscriptions.push({
+              event: eventName,
+              contextDescriptor: {
+                type: lazy.ContextDescriptorType.TopBrowsingContext,
+                id: this.#getBrowserIdForContextId(contextId),
+              },
+              callback: this.#onMessageHandlerEvent,
+              enable: true,
+            });
+          } else if (!enabled) {
+            // Unsubscribe from each event for a specific context id if the event has a subscription.
+            if (target.has(eventName)) {
+              target.delete(eventName);
+
+              subscriptions.push({
+                event: eventName,
+                contextDescriptor: {
+                  type: lazy.ContextDescriptorType.TopBrowsingContext,
+                  id: this.#getBrowserIdForContextId(contextId),
+                },
+                callback: this.#onMessageHandlerEvent,
+                enable: false,
+              });
+            } else {
+              throw new lazy.error.InvalidArgumentError(
+                `Failed to unsubscribe from event ${eventName} for context ${contextId}`
+              );
+            }
+          }
+        }
+      }
+    }
+
+    this.#globalEventSet = globalEventSet;
+    this.#browsingContextIdEventMap = eventMap;
+
+    return subscriptions;
+  }
+}
+
+// To export the class as lower-case
+export const session = SessionModule;