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Commit 73676b48 authored by Darryl L Johnson's avatar Darryl L Johnson
Browse files

Add onDeviceStateChanged() callback to DeviceStateManager. 

This change introduces the DeviceStateCallback API to DeviceStateManager
which allows processes outside system_server (as well as system_server)
to receive notifications about changes in the system's device state.

Test: atest DeviceStateManagerServiceTest
Bug: 159401801

Change-Id: I9ccdbd8c4a51858a13b0152ed39a8bf20e41e64f
parent 8ca4e81d

core/java/android/hardware/devicestate/DeviceStateManager.java

+45 −1
Original line number Diff line number Diff line
@@ -16,9 +16,12 @@ 


package android.hardware.devicestate;



import android.annotation.NonNull;

import android.annotation.SystemService;

import android.content.Context;



import java.util.concurrent.Executor;



/**

 * Manages the state of the system for devices with user-configurable hardware like a foldable

 * phone.
@@ -33,6 +36,47 @@ public final class DeviceStateManager { 
    private DeviceStateManagerGlobal mGlobal;



    public DeviceStateManager() {

        mGlobal = DeviceStateManagerGlobal.getInstance();

        DeviceStateManagerGlobal global = DeviceStateManagerGlobal.getInstance();

        if (global == null) {

            throw new IllegalStateException(

                    "Failed to get instance of global device state manager.");

        }

        mGlobal = global;

    }



    /**

     * Registers a listener to receive notifications about changes in device state.

     *

     * @param listener the listener to register.

     * @param executor the executor to process notifications.

     *

     * @see DeviceStateListener

     */

    public void registerDeviceStateListener(@NonNull DeviceStateListener listener,

            @NonNull Executor executor) {

        mGlobal.registerDeviceStateListener(listener, executor);

    }



    /**

     * Unregisters a listener previously registered with

     * {@link #registerDeviceStateListener(DeviceStateListener, Executor)}.

     */

    public void unregisterDeviceStateListener(@NonNull DeviceStateListener listener) {

        mGlobal.unregisterDeviceStateListener(listener);

    }



    /**

     * Listens for changes in device states.

     */

    public interface DeviceStateListener {

        /**

         * Called in response to device state changes.

         * <p>

         * Guaranteed to be called once on registration of the listener with the

         * initial value and then on every subsequent change in device state.

         *

         * @param deviceState the new device state.

         */

        void onDeviceStateChanged(int deviceState);

    }

}

core/java/android/hardware/devicestate/DeviceStateManagerGlobal.java

+123 −2
Original line number Diff line number Diff line
@@ -19,16 +19,26 @@ package android.hardware.devicestate; 
import android.annotation.NonNull;

import android.annotation.Nullable;

import android.content.Context;

import android.hardware.devicestate.DeviceStateManager.DeviceStateListener;

import android.os.IBinder;

import android.os.RemoteException;

import android.os.ServiceManager;



import com.android.internal.annotations.GuardedBy;

import com.android.internal.annotations.VisibleForTesting;

import com.android.internal.annotations.VisibleForTesting.Visibility;



import java.util.ArrayList;

import java.util.concurrent.Executor;



/**

 * Provides communication with the device state system service on behalf of applications.

 *

 * @see DeviceStateManager

 * @hide

 */

final class DeviceStateManagerGlobal {

@VisibleForTesting(visibility = Visibility.PACKAGE)

public final class DeviceStateManagerGlobal {

    private static DeviceStateManagerGlobal sInstance;



    /**
@@ -49,10 +59,121 @@ final class DeviceStateManagerGlobal { 
        }

    }



    private final Object mLock = new Object();

    @NonNull

    private final IDeviceStateManager mDeviceStateManager;

    @Nullable

    private DeviceStateManagerCallback mCallback;



    private DeviceStateManagerGlobal(@NonNull IDeviceStateManager deviceStateManager) {

    @GuardedBy("mLock")

    private final ArrayList<DeviceStateListenerWrapper> mListeners = new ArrayList<>();

    @Nullable

    @GuardedBy("mLock")

    private Integer mLastReceivedState;



    @VisibleForTesting

    public DeviceStateManagerGlobal(@NonNull IDeviceStateManager deviceStateManager) {

        mDeviceStateManager = deviceStateManager;

    }



    /**

     * Registers a listener to receive notifications about changes in device state.

     *

     * @see DeviceStateManager#registerDeviceStateListener(DeviceStateListener, Executor)

     */

    @VisibleForTesting(visibility = Visibility.PACKAGE)

    public void registerDeviceStateListener(@NonNull DeviceStateListener listener,

            @NonNull Executor executor) {

        Integer stateToReport;

        DeviceStateListenerWrapper wrapper;

        synchronized (mLock) {

            registerCallbackIfNeededLocked();



            int index = findListenerLocked(listener);

            if (index != -1) {

                // This listener is already registered.

                return;

            }



            wrapper = new DeviceStateListenerWrapper(listener, executor);

            mListeners.add(wrapper);

            stateToReport = mLastReceivedState;

        }



        if (stateToReport != null) {

            // Notify the listener with the most recent device state from the server. If the state

            // to report is null this is likely the first listener added and we're still waiting

            // from the callback from the server.

            wrapper.notifyDeviceStateChanged(stateToReport);

        }

    }



    /**

     * Unregisters a listener previously registered with

     * {@link #registerDeviceStateListener(DeviceStateListener, Executor)}.

     *

     * @see DeviceStateManager#registerDeviceStateListener(DeviceStateListener, Executor)

     */

    @VisibleForTesting(visibility = Visibility.PACKAGE)

    public void unregisterDeviceStateListener(DeviceStateListener listener) {

        synchronized (mLock) {

            int indexToRemove = findListenerLocked(listener);

            if (indexToRemove != -1) {

                mListeners.remove(indexToRemove);

            }

        }

    }



    private void registerCallbackIfNeededLocked() {

        if (mCallback == null) {

            mCallback = new DeviceStateManagerCallback();

            try {

                mDeviceStateManager.registerCallback(mCallback);

            } catch (RemoteException ex) {

                throw ex.rethrowFromSystemServer();

            }

        }

    }



    private int findListenerLocked(DeviceStateListener listener) {

        for (int i = 0; i < mListeners.size(); i++) {

            if (mListeners.get(i).mDeviceStateListener.equals(listener)) {

                return i;

            }

        }

        return -1;

    }



    private void handleDeviceStateChanged(int newDeviceState) {

        ArrayList<DeviceStateListenerWrapper> listeners;

        synchronized (mLock) {

            mLastReceivedState = newDeviceState;

            listeners = new ArrayList<>(mListeners);

        }



        for (int i = 0; i < listeners.size(); i++) {

            listeners.get(i).notifyDeviceStateChanged(newDeviceState);

        }

    }



    private final class DeviceStateManagerCallback extends IDeviceStateManagerCallback.Stub {

        @Override

        public void onDeviceStateChanged(int deviceState) {

            handleDeviceStateChanged(deviceState);

        }

    }



    private static final class DeviceStateListenerWrapper {

        private final DeviceStateListener mDeviceStateListener;

        private final Executor mExecutor;



        DeviceStateListenerWrapper(DeviceStateListener listener, Executor executor) {

            mDeviceStateListener = listener;

            mExecutor = executor;

        }



        void notifyDeviceStateChanged(int newDeviceState) {

            mExecutor.execute(() -> mDeviceStateListener.onDeviceStateChanged(newDeviceState));

        }

    }

}

core/java/android/hardware/devicestate/IDeviceStateManager.aidl

+5 −1
Original line number Diff line number Diff line
@@ -16,5 +16,9 @@ 


package android.hardware.devicestate;



import android.hardware.devicestate.IDeviceStateManagerCallback;



/** @hide */

interface IDeviceStateManager {}
 
interface IDeviceStateManager {

    void registerCallback(in IDeviceStateManagerCallback callback);

}

core/java/android/hardware/devicestate/IDeviceStateManagerCallback.aidl

0 → 100644
+22 −0
Original line number Diff line number Diff line 
/**

 * 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.hardware.devicestate;



/** @hide */

interface IDeviceStateManagerCallback {

    oneway void onDeviceStateChanged(int deviceState);

}

core/tests/devicestatetests/Android.bp

0 → 100644
+26 −0
Original line number Diff line number Diff line 
// 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.



android_test {

    name: "FrameworksCoreDeviceStateManagerTests",

    // Include all test java files

    srcs: ["src/**/*.java"],

    static_libs: [

        "androidx.test.rules",

        "frameworks-base-testutils",

    ],

    libs: ["android.test.runner"],

    platform_apis: true,

    certificate: "platform",

}