Introduce WindowContextController

This CL extracts the logic which is going to share with
WindowProviderService. It is also the preparation to introduce
WindowProviderService.

Bug: 159767464
Test: atest WindowContextControllerTest

Change-Id: Ib5a4cc8d7853bb01bde1081af091d1069865e3a0

1 files changed, 96 insertions, 0 deletions

diff --git a/core/java/android/window/WindowContextController.java b/core/java/android/window/WindowContextController.java
new file mode 100644
index 000000000000..61434145290f
--- /dev/null
+++ b/core/java/android/window/WindowContextController.java
@@ -0,0 +1,96 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.window;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.content.Context;
+import android.os.Bundle;
+import android.os.IBinder;
+import android.os.RemoteException;
+import android.view.IWindowManager;
+import android.view.WindowManager.LayoutParams.WindowType;
+import android.view.WindowManagerGlobal;
+
+import com.android.internal.annotations.VisibleForTesting;
+
+/**
+ * The controller to manage {@link WindowContext} listener, such as registering and unregistering
+ * the listener.
+ *
+ * @hide
+ */
+public class WindowContextController {
+    private final IWindowManager mWms;
+    @VisibleForTesting
+    public boolean mListenerRegistered;
+    @NonNull
+    private final IBinder mToken;
+
+    /**
+     * Window Context Controller constructor
+     *
+     * @param token The token to register to the window context listener. It is usually from
+     *              {@link Context#getWindowContextToken()}.
+     */
+    public WindowContextController(@NonNull IBinder token) {
+        mToken = token;
+        mWms = WindowManagerGlobal.getWindowManagerService();
+    }
+
+    /** Used for test only. DO NOT USE it in production code. */
+    @VisibleForTesting
+    public WindowContextController(@NonNull IBinder token, IWindowManager mockWms) {
+        mToken = token;
+        mWms = mockWms;
+    }
+
+    /**
+     * Registers the {@code mToken} to the window context listener.
+     *
+     * @param type The window type of the {@link WindowContext}
+     * @param displayId The {@link Context#getDisplayId() ID of display} to associate with
+     * @param options The window context launched option
+     */
+    public void registerListener(@WindowType int type, int displayId,  @Nullable Bundle options) {
+        if (mListenerRegistered) {
+            throw new UnsupportedOperationException("A Window Context can only register a listener"
+                    + " once.");
+        }
+        try {
+            mListenerRegistered = mWms.registerWindowContextListener(mToken, type, displayId,
+                    options);
+        }  catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /**
+     * Unregisters the window context listener associated with the {@code mToken} if it has been
+     * registered.
+     */
+    public void unregisterListenerIfNeeded() {
+        if (mListenerRegistered) {
+            try {
+                mWms.unregisterWindowContextListener(mToken);
+                mListenerRegistered = false;
+            } catch (RemoteException e) {
+                throw e.rethrowFromSystemServer();
+            }
+        }
+    }
+}