android/app/src/com/android/bluetooth/a2dpsink/A2dpSinkStateMachine.java

/*
 * Copyright (C) 2014 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 com.android.bluetooth.a2dpsink;

import static android.Manifest.permission.BLUETOOTH_CONNECT;

import android.annotation.RequiresPermission;
import android.bluetooth.BluetoothA2dpSink;
import android.bluetooth.BluetoothAudioConfig;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothProfile;
import android.content.Intent;
import android.media.AudioFormat;
import android.os.Looper;
import android.os.Message;
import android.util.Log;

import com.android.bluetooth.BluetoothMetricsProto;
import com.android.bluetooth.Utils;
import com.android.bluetooth.btservice.MetricsLogger;
import com.android.bluetooth.btservice.ProfileService;
import com.android.internal.annotations.VisibleForTesting;
import com.android.internal.util.State;
import com.android.internal.util.StateMachine;

class A2dpSinkStateMachine extends StateMachine {
    private static final String TAG = A2dpSinkStateMachine.class.getSimpleName();
    static final boolean DBG = Log.isLoggable(TAG, Log.DEBUG);

    // 0->99 Events from Outside
    @VisibleForTesting static final int CONNECT = 1;
    @VisibleForTesting static final int DISCONNECT = 2;

    // 100->199 Internal Events
    @VisibleForTesting static final int CLEANUP = 100;
    @VisibleForTesting static final int CONNECT_TIMEOUT = 101;

    // 200->299 Events from Native
    @VisibleForTesting static final int STACK_EVENT = 200;

    static final int CONNECT_TIMEOUT_MS = 10000;

    protected final BluetoothDevice mDevice;
    protected final byte[] mDeviceAddress;
    protected final A2dpSinkService mService;
    protected final A2dpSinkNativeInterface mNativeInterface;
    protected final Disconnected mDisconnected;
    protected final Connecting mConnecting;
    protected final Connected mConnected;
    protected final Disconnecting mDisconnecting;

    protected int mMostRecentState = BluetoothProfile.STATE_DISCONNECTED;
    protected BluetoothAudioConfig mAudioConfig = null;

    A2dpSinkStateMachine(
            Looper looper,
            BluetoothDevice device,
            A2dpSinkService service,
            A2dpSinkNativeInterface nativeInterface) {
        super(TAG, looper);
        mDevice = device;
        mDeviceAddress = Utils.getByteAddress(mDevice);
        mService = service;
        mNativeInterface = nativeInterface;
        if (DBG) Log.d(TAG, device.toString());

        mDisconnected = new Disconnected();
        mConnecting = new Connecting();
        mConnected = new Connected();
        mDisconnecting = new Disconnecting();

        addState(mDisconnected);
        addState(mConnecting);
        addState(mConnected);
        addState(mDisconnecting);

        setInitialState(mDisconnected);
    }

    /**
     * Get the current connection state
     *
     * @return current State
     */
    public int getState() {
        return mMostRecentState;
    }

    /**
     * get current audio config
     */
    BluetoothAudioConfig getAudioConfig() {
        return mAudioConfig;
    }

    /**
     * Get the underlying device tracked by this state machine
     *
     * @return device in focus
     */
    public synchronized BluetoothDevice getDevice() {
        return mDevice;
    }

    /** send the Connect command asynchronously */
    final void connect() {
        sendMessage(CONNECT);
    }

    /** send the Disconnect command asynchronously */
    final void disconnect() {
        sendMessage(DISCONNECT);
    }

    /** send the stack event asynchronously */
    final void onStackEvent(StackEvent event) {
        sendMessage(STACK_EVENT, event);
    }

    /**
     * Dump the current State Machine to the string builder.
     * @param sb output string
     */
    public void dump(StringBuilder sb) {
        ProfileService.println(sb, "mDevice: " + mDevice + "("
                + Utils.getName(mDevice) + ") " + this.toString());
    }

    @Override
    protected void unhandledMessage(Message msg) {
        Log.w(TAG, "unhandledMessage in state " + getCurrentState() + "msg.what=" + msg.what);
    }

    class Disconnected extends State {
        @Override
        public void enter() {
            if (DBG) Log.d(TAG, "Enter Disconnected");
            if (mMostRecentState != BluetoothProfile.STATE_DISCONNECTED) {
                sendMessage(CLEANUP);
            }
            onConnectionStateChanged(BluetoothProfile.STATE_DISCONNECTED);
        }

        @Override
        public boolean processMessage(Message message) {
            switch (message.what) {
                case STACK_EVENT:
                    processStackEvent((StackEvent) message.obj);
                    return true;
                case CONNECT:
                    if (DBG) Log.d(TAG, "Connect");
                    transitionTo(mConnecting);
                    return true;
                case CLEANUP:
                    mService.removeStateMachine(A2dpSinkStateMachine.this);
                    return true;
            }
            return false;
        }

        @RequiresPermission(android.Manifest.permission.BLUETOOTH_PRIVILEGED)
        void processStackEvent(StackEvent event) {
            switch (event.mType) {
                case StackEvent.EVENT_TYPE_CONNECTION_STATE_CHANGED:
                    switch (event.mState) {
                        case StackEvent.CONNECTION_STATE_CONNECTING:
                            if (mService.getConnectionPolicy(mDevice)
                                    == BluetoothProfile.CONNECTION_POLICY_FORBIDDEN) {
                                Log.w(TAG, "Ignore incoming connection, profile is"
                                        + " turned off for " + mDevice);
                                mNativeInterface.disconnectA2dpSink(mDevice);
                            } else {
                                mConnecting.mIncomingConnection = true;
                                transitionTo(mConnecting);
                            }
                            break;
                        case StackEvent.CONNECTION_STATE_CONNECTED:
                            transitionTo(mConnected);
                            break;
                        case StackEvent.CONNECTION_STATE_DISCONNECTED:
                            sendMessage(CLEANUP);
                            break;
                    }
            }
        }
    }

    class Connecting extends State {
        boolean mIncomingConnection = false;

        @Override
        public void enter() {
            if (DBG) Log.d(TAG, "Enter Connecting");
            onConnectionStateChanged(BluetoothProfile.STATE_CONNECTING);
            sendMessageDelayed(CONNECT_TIMEOUT, CONNECT_TIMEOUT_MS);

            if (!mIncomingConnection) {
                mNativeInterface.connectA2dpSink(mDevice);
            }

            super.enter();
        }

        @Override
        public boolean processMessage(Message message) {
            switch (message.what) {
                case STACK_EVENT:
                    processStackEvent((StackEvent) message.obj);
                    return true;
                case CONNECT_TIMEOUT:
                    transitionTo(mDisconnected);
                    return true;
                case DISCONNECT:
                    Log.d(TAG, "Received disconnect message while connecting. deferred");
                    deferMessage(message);
                    return true;
            }
            return false;
        }

        void processStackEvent(StackEvent event) {
            switch (event.mType) {
                case StackEvent.EVENT_TYPE_CONNECTION_STATE_CHANGED:
                    switch (event.mState) {
                        case StackEvent.CONNECTION_STATE_CONNECTED:
                            transitionTo(mConnected);
                            break;
                        case StackEvent.CONNECTION_STATE_DISCONNECTED:
                            transitionTo(mDisconnected);
                            break;
                    }
            }
        }
        @Override
        public void exit() {
            removeMessages(CONNECT_TIMEOUT);
            mIncomingConnection = false;
        }

    }

    class Connected extends State {
        @Override
        public void enter() {
            if (DBG) Log.d(TAG, "Enter Connected");
            onConnectionStateChanged(BluetoothProfile.STATE_CONNECTED);
        }

        @Override
        public boolean processMessage(Message message) {
            switch (message.what) {
                case DISCONNECT:
                    transitionTo(mDisconnecting);
                    mNativeInterface.disconnectA2dpSink(mDevice);
                    return true;
                case STACK_EVENT:
                    processStackEvent((StackEvent) message.obj);
                    return true;
            }
            return false;
        }

        void processStackEvent(StackEvent event) {
            switch (event.mType) {
                case StackEvent.EVENT_TYPE_CONNECTION_STATE_CHANGED:
                    switch (event.mState) {
                        case StackEvent.CONNECTION_STATE_DISCONNECTING:
                            transitionTo(mDisconnecting);
                            break;
                        case StackEvent.CONNECTION_STATE_DISCONNECTED:
                            transitionTo(mDisconnected);
                            break;
                    }
                    break;
                case StackEvent.EVENT_TYPE_AUDIO_CONFIG_CHANGED:
                    mAudioConfig = new BluetoothAudioConfig(event.mSampleRate, event.mChannelCount,
                            AudioFormat.ENCODING_PCM_16BIT);
                    break;
            }
        }
    }

    protected class Disconnecting extends State {
        @Override
        public void enter() {
            if (DBG) Log.d(TAG, "Enter Disconnecting");
            onConnectionStateChanged(BluetoothProfile.STATE_DISCONNECTING);
            transitionTo(mDisconnected);
        }
    }

    protected void onConnectionStateChanged(int currentState) {
        if (mMostRecentState == currentState) {
            return;
        }
        if (currentState == BluetoothProfile.STATE_CONNECTED) {
            MetricsLogger.logProfileConnectionEvent(BluetoothMetricsProto.ProfileId.A2DP_SINK);
        }
        if (DBG) {
            Log.d(TAG, "Connection state " + mDevice + ": " + mMostRecentState + "->"
                    + currentState);
        }
        Intent intent = new Intent(BluetoothA2dpSink.ACTION_CONNECTION_STATE_CHANGED);
        intent.putExtra(BluetoothProfile.EXTRA_PREVIOUS_STATE, mMostRecentState);
        intent.putExtra(BluetoothProfile.EXTRA_STATE, currentState);
        intent.putExtra(BluetoothDevice.EXTRA_DEVICE, mDevice);
        intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);
        mMostRecentState = currentState;
        Utils.sendBroadcast(mService, intent, BLUETOOTH_CONNECT,
                Utils.getTempAllowlistBroadcastOptions());
    }
}