Introduce WindowContext API

Test: atest WmTests CtsWindowManagerDeviceTestCases
Bug: 128338354
Change-Id: I9c9dfc5e7f4edd4c968e60d2ffcbb19b5c72a853

1 files changed, 123 insertions, 0 deletions

diff --git a/core/java/android/app/WindowContext.java b/core/java/android/app/WindowContext.java
new file mode 100644
index 000000000000..22cc14bd5ed6
--- /dev/null
+++ b/core/java/android/app/WindowContext.java
@@ -0,0 +1,123 @@
+/*
+ * Copyright (C) 2020 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.app;
+
+import android.annotation.NonNull;
+import android.content.Context;
+import android.content.ContextWrapper;
+import android.os.Binder;
+import android.os.Bundle;
+import android.os.IBinder;
+import android.os.RemoteException;
+import android.view.IWindowManager;
+import android.view.WindowManagerGlobal;
+import android.view.WindowManagerImpl;
+
+/**
+ * {@link WindowContext} is a context for non-activity windows such as
+ * {@link android.view.WindowManager.LayoutParams#TYPE_APPLICATION_OVERLAY} windows or system
+ * windows. Its resources and configuration are adjusted to the area of the display that will be
+ * used when a new window is added via {@link android.view.WindowManager.addView}.
+ *
+ * @see Context#createWindowContext(int)
+ * @hide
+ */
+// TODO(b/128338354): Handle config/display changes from server side.
+public class WindowContext extends ContextWrapper {
+    private final WindowManagerImpl mWindowManager;
+    private final IWindowManager mWms;
+    private final IBinder mToken;
+    private final int mDisplayId;
+    private boolean mOwnsToken;
+
+    /**
+     * Default constructor. Can either accept an existing token or generate one and registers it
+     * with the server if necessary.
+     *
+     * @param base Base {@link Context} for this new instance.
+     * @param token A valid {@link com.android.server.wm.WindowToken}. Pass {@code null} to generate
+     *              one.
+     * @param type Window type to be used with this context.
+     * @hide
+     */
+    public WindowContext(Context base, IBinder token, int type) {
+        super(null /* base */);
+
+        mWms = WindowManagerGlobal.getWindowManagerService();
+        if (token != null && !isWindowToken(token)) {
+            throw new IllegalArgumentException("Token must be registered to server.");
+        }
+
+        final ContextImpl contextImpl = createBaseWindowContext(base, token);
+        attachBaseContext(contextImpl);
+        contextImpl.setOuterContext(this);
+
+        mToken = token != null ? token : new Binder();
+        mDisplayId = getDisplayId();
+        mWindowManager = new WindowManagerImpl(this);
+        mWindowManager.setDefaultToken(mToken);
+
+        // TODO(b/128338354): Obtain the correct config from WM and adjust resources.
+        if (token != null) {
+            mOwnsToken = false;
+            return;
+        }
+        try {
+            mWms.addWindowContextToken(mToken, type, mDisplayId, getPackageName());
+            // TODO(window-context): remove token with a DeathObserver
+        }  catch (RemoteException e) {
+            mOwnsToken = false;
+            throw e.rethrowFromSystemServer();
+        }
+        mOwnsToken = true;
+    }
+
+    /** Check if the passed window token is registered with the server. */
+    private boolean isWindowToken(@NonNull IBinder token) {
+        try {
+            return mWms.isWindowToken(token);
+        } catch (RemoteException e) {
+            e.rethrowFromSystemServer();
+        }
+        return false;
+    }
+
+    private static ContextImpl createBaseWindowContext(Context outer, IBinder token) {
+        final ContextImpl contextImpl = ContextImpl.getImpl(outer);
+        return contextImpl.createBaseWindowContext(token);
+    }
+
+    @Override
+    public Object getSystemService(String name) {
+        if (WINDOW_SERVICE.equals(name)) {
+            return mWindowManager;
+        }
+        return super.getSystemService(name);
+    }
+
+    @Override
+    protected void finalize() throws Throwable {
+        if (mOwnsToken) {
+            try {
+                mWms.removeWindowToken(mToken, mDisplayId);
+                mOwnsToken = false;
+            } catch (RemoteException e) {
+                throw e.rethrowFromSystemServer();
+            }
+        }
+        super.finalize();
+    }
+}