GTW-4243 Refactor notifications flow for remote sessions

Instead of subscribing to the notification topic and sending received notifications to a client, choose what notification should process the notification.
That would prevent notification duplication in RD mode (we were processing the same notification twice - by backend and local managers)

To achieve described behavior:
- Introduce NotificationRouter as an extension poitn and different implementations for local/controller/guest scenarios. The notification will be processed by the first applicable router
- Move NotificationsListener outside NotificationsManagerImpl, so we could process notifications by the right router
- add showNotification method to NotificationsManager abstract class, so we can access it from outside
- BackendNotificationsHost becomes application-level service (instead of project-level)

Notification routers:
- Guest: If notifications is sent under client's id, we send notification to that client
- Controller: If notification is sent under local id, we check is there an active controller session (we are in RD mode). If there is, we sent all notifications to that controller
- Local: Otherwise we process notification by the local manager

GitOrigin-RevId: c6f9e365c15acfea81145a9acf33ff8bb82013a5

platform/ide-core/src/com/intellij/notification/NotificationRouter.kt

@@ -0,0 +1,27 @@
+// Copyright 2000-2023 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package com.intellij.notification
+
+import com.intellij.openapi.extensions.ExtensionPointName
+import com.intellij.openapi.project.Project
+
+/**
+ * Interface for a notification router.
+ *
+ * This interface defines a method for routing a notification to some notification manager
+ * Implementations of this interface can be registered as extension points.
+ */
+interface NotificationRouter {
+
+  /**
+   * Routes a notification to some notification manager to be processed
+   *
+   * @param notification The notification to be routed.
+   * @param project The project notification should be shown for
+   * @return Returns true if the notification is routed to some manager, false otherwise.
+   */
+  fun routeNotification(notification: Notification, project: Project?): Boolean
+
+  companion object {
+    val EP_NAME: ExtensionPointName<NotificationRouter> = ExtensionPointName("com.intellij.notificationRouter")
+  }
+}

platform/ide-core/src/com/intellij/notification/NotificationsManager.java

@@ -11,6 +11,8 @@ public abstract class NotificationsManager {
     return ApplicationManager.getApplication().getService(NotificationsManager.class);
   }
 
+  public abstract void showNotification(@NotNull Notification notification, @Nullable Project project);
+
   public abstract void expire(@NotNull Notification notification);
 
   public abstract <T extends Notification> T @NotNull [] getNotificationsOfType(@NotNull Class<T> klass, @Nullable Project project);

platform/platform-impl/src/com/intellij/notification/impl/LocalNotificationRouter.kt

@@ -0,0 +1,13 @@
+// Copyright 2000-2023 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package com.intellij.notification.impl
+
+import com.intellij.notification.Notification
+import com.intellij.notification.NotificationRouter
+import com.intellij.openapi.project.Project
+
+class LocalNotificationRouter: NotificationRouter {
+  override fun routeNotification(notification: Notification, project: Project?): Boolean {
+    NotificationsManagerImpl.getNotificationsManager().showNotification(notification, project)
+    return true
+  }
+}

platform/platform-impl/src/com/intellij/notification/impl/NotificationsListener.kt

@@ -0,0 +1,43 @@
+// Copyright 2000-2023 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package com.intellij.notification.impl
+
+import com.intellij.notification.Notification
+import com.intellij.notification.NotificationRouter
+import com.intellij.notification.Notifications
+import com.intellij.notification.impl.NotificationsManagerImpl.isDummyEnvironment
+import com.intellij.openapi.diagnostic.logger
+import com.intellij.openapi.extensions.ExtensionNotApplicableException
+import com.intellij.openapi.project.Project
+
+class NotificationsListener : Notifications {
+  private val project: Project?
+
+  @Suppress("unused")
+  constructor() {
+    project = null
+  }
+
+  @Suppress("unused")
+  private constructor(project: Project?) {
+    this.project = project
+    if (isDummyEnvironment()) {
+      throw ExtensionNotApplicableException.create()
+    }
+  }
+
+  override fun notify(notification: Notification) {
+    for (listener in NotificationRouter.EP_NAME.extensionList) {
+      try {
+        if (listener.routeNotification(notification, project)) {
+          return
+        }
+      } catch (e: Throwable) {
+        LOG.error(e)
+      }
+    }
+  }
+
+  companion object {
+    private val LOG = logger<NotificationsListener>()
+  }
+}

platform/platform-impl/src/com/intellij/notification/impl/NotificationsManagerImpl.java

@@ -126,7 +126,8 @@ public final class NotificationsManagerImpl extends NotificationsManager {
     return ArrayUtil.toObjectArray(result, klass);
   }
 
-  private void doNotify(Notification notification, @Nullable Project project) {
+  @Override
+  public void showNotification(@NotNull Notification notification, @Nullable Project project) {
     NotificationsConfigurationImpl configuration = NotificationsConfigurationImpl.getInstanceImpl();
     NotificationSettings settings = NotificationsConfigurationImpl.getSettings(notification.getGroupId());
 
@@ -166,7 +167,7 @@ public final class NotificationsManagerImpl extends NotificationsManager {
   }
 
   @RequiresEdt
-  private void showNotification(Notification notification, @Nullable Project project) {
+  private void showNotificationInner(Notification notification, @Nullable Project project) {
     if (LOG.isDebugEnabled()) LOG.debug("incoming: " + notification + ", project=" + project);
 
     if (myEarlyNotifications != null) {
@@ -297,7 +298,7 @@ public final class NotificationsManagerImpl extends NotificationsManager {
         span.setAttribute("project", project.toString());
       }
       span.setAttribute("notification", notification.toString());
-      showNotification(notification, project);
+      showNotificationInner(notification, project);
     });
   }
 
@@ -1135,7 +1136,7 @@ public final class NotificationsManagerImpl extends NotificationsManager {
     return text.getPreferredSize().height;
   }
 
-  private static boolean isDummyEnvironment() {
+  static boolean isDummyEnvironment() {
     Application app = ApplicationManager.getApplication();
     return app.isUnitTestMode() || app.isCommandLine();
   }
@@ -1234,27 +1235,6 @@ public final class NotificationsManagerImpl extends NotificationsManager {
     return null;
   }
 
-  static final class MyNotificationListener implements Notifications {
-    private final Project project;
-
-    @SuppressWarnings("unused")
-    MyNotificationListener() {
-      project = null;
-    }
-
-    @SuppressWarnings("unused")
-    private MyNotificationListener(@Nullable Project project) {
-      this.project = project;
-      if (isDummyEnvironment()) {
-        throw ExtensionNotApplicableException.create();
-      }
-    }
-
-    @Override
-    public void notify(@NotNull Notification notification) {
-      ((NotificationsManagerImpl)NotificationsManager.getNotificationsManager()).doNotify(notification, project);
-    }
-  }
 
   private static @Nullable Point getCollapsedTextEndLocation(JEditorPane text, BalloonLayoutData layoutData) {
     try {

platform/platform-resources/src/META-INF/PlatformExtensionPoints.xml

@@ -524,5 +524,6 @@
 
     <extensionPoint name="meetNewUiCustomization" interface="com.intellij.ide.ui.experimental.meetNewUi.MeetNewUiCustomization" dynamic="true"/>
 
+    <extensionPoint name="notificationRouter" interface="com.intellij.notification.NotificationRouter" dynamic="true"/>
   </extensionPoints>
 </idea-plugin>

platform/platform-resources/src/META-INF/PlatformExtensions.xml

@@ -1552,6 +1552,8 @@
     <toolbarQuickAction implementationClass="com.intellij.openapi.wm.impl.headertoolbar.BuildQuickAction" listGroupID="MainToolbarQuickActions.Run" />
     <toolbarQuickAction implementationClass="com.intellij.openapi.wm.impl.headertoolbar.CoverageQuickAction" listGroupID="MainToolbarQuickActions.Run" />
     <toolbarQuickAction implementationClass="com.intellij.openapi.wm.impl.headertoolbar.ProfilerQuickAction" listGroupID="MainToolbarQuickActions.Run" />
+
+    <notificationRouter implementation="com.intellij.notification.impl.LocalNotificationRouter" order="last"/>
   </extensions>
 
   <extensions defaultExtensionNs="org.jetbrains">
@@ -1612,7 +1614,7 @@
   </applicationListeners>
 
   <projectListeners>
-    <listener class="com.intellij.notification.impl.NotificationsManagerImpl$MyNotificationListener"
+    <listener class="com.intellij.notification.impl.NotificationsListener"
               activeInHeadlessMode="false"
               activeInTestMode="false"
               topic="com.intellij.notification.Notifications"/>

platform/platform-resources/src/META-INF/PlatformLangComponents.xml

@@ -182,7 +182,7 @@
 
     <listener class="com.intellij.notification.impl.NotificationsToolWindowNotificationListener"
               topic="com.intellij.notification.Notifications"/>
-    <listener class="com.intellij.notification.impl.NotificationsManagerImpl$MyNotificationListener"
+    <listener class="com.intellij.notification.impl.NotificationsListener"
               topic="com.intellij.notification.Notifications"/>
     <listener class="com.intellij.notification.impl.NotificationsConfigurationImpl$MyNotificationListener"
               topic="com.intellij.notification.Notifications"/>