Bluetooth initialization - enabl

作者: MelanDawn | 来源:发表于2022-05-02 20:15 被阅读0次

Bluetooth initialization - enabl
Bluetooth initialization - enabl
Bluetooth initialization - enabl
Bluetooth initialization - enabl
Bluetooth initialization - enabl
Bluetooth initialization - Bluet
Bluetooth initialization - Bluet
直接初始化和拷贝初始化
Swift学习—— initialization构造过程
蓝牙笔记 | 代码目录介绍

1. Bluetooth Enable Overview

1.1 Bluetooth Enable Entrance

packages/apps/Bluetooth/src/com/android/bluetooth/btservice/AdapterService.java

    public static class AdapterServiceBinder extends IBluetooth.Stub {
        @Override
        public boolean enable(boolean quietMode) {
            AdapterService service = getService();
......
            return service.enable(quietMode);
        }
    }



    public synchronized boolean enable(boolean quietMode) {
......
        mQuietmode = quietMode;     // 由上层传递，测试设备的值 false
        mAdapterStateMachine.sendMessage(AdapterState.BLE_TURN_ON);
        return true;
    }

1.2 Bluetooth StateMachine Overview

packages/apps/Bluetooth/src/com/android/bluetooth/btservice/AdapterState.java
根据源码注释可知，蓝牙开启的状态转换关系如下图：

蓝牙启动的状态机转换图.png

由上图可知，经历 Off、TurningBleOn、BleOn、TurningOn、On 共五个状态，蓝牙处于完全的开启状态。
五个状态中，仅仅 TurningBleOn 和 TurningOn 是不稳定状态，无论操作成功与否都需要恢复到稳定状态 Off、BleOn、On 三种状态中的一种。

下面开始分析蓝牙 enable 整体流程，分为 TurningBleOn 和 TurningOn 两个流程分析。
首先整体介绍 enable 流程中状态机的转化，再分析 TurningBleOn，最后分析 TurningOn。

packages/apps/Bluetooth/src/com/android/bluetooth/btservice/AdapterState.java

final class AdapterState extends StateMachine {

    // 所有状态的基类
    private abstract class BaseAdapterState extends State {

        abstract int getStateValue();

        // 进入所有的具体状态时，需要更新状态信息。（若子类未重写）
        @Override
        public void enter() {
            int currState = getStateValue();
            mAdapterService.updateAdapterState(mPrevState, currState);     // 0
            mPrevState = currState;
        }
......
    }


    private class OffState extends BaseAdapterState {
        @Override
        public boolean processMessage(Message msg) {
            switch (msg.what) {
                case BLE_TURN_ON:
                    transitionTo(mTurningBleOnState);        // 1
                    break;
            }
            return true;
        }
    }



    private class TurningBleOnState extends BaseAdapterState {

        @Override
        public void enter() {
            super.enter();
            sendMessageDelayed(BLE_START_TIMEOUT, BLE_START_TIMEOUT_DELAY);
            mAdapterService.bringUpBle();                  // 2
        }

        @Override
        public boolean processMessage(Message msg) {
            switch (msg.what) {
                case BLE_STARTED:
                    transitionTo(mBleOnState);             // 3
                    break;
......
            }
            return true;
        }
    }



    private class BleOnState extends BaseAdapterState {

        @Override
        public boolean processMessage(Message msg) {
            switch (msg.what) {
                case USER_TURN_ON:
                    transitionTo(mTurningOnState);        // 4
                    break;
......
            }
            return true;
        }
    }



    private class TurningOnState extends BaseAdapterState {

        @Override
        public void enter() {
            super.enter();
            sendMessageDelayed(BREDR_START_TIMEOUT, BREDR_START_TIMEOUT_DELAY);
            mAdapterService.startProfileServices();      // 5
        }

        @Override
        public boolean processMessage(Message msg) {
            switch (msg.what) {
                case BREDR_STARTED:
                    transitionTo(mOnState);              // 6
                    break;
......
            }
            return true;
        }
    }


    private class OnState extends BaseAdapterState {

        @Override
        public boolean processMessage(Message msg) {
            switch (msg.what) {
                case USER_TURN_OFF:
                    transitionTo(mTurningOffState);
                    break;

            }
            return true;
        }
    }
}

从以上 0~6 共计 7 个数字注释可知，除了状态转移，状态机主要执行三个方法：

mAdapterService.updateAdapterState(mPrevState, currState); 【//0，通用方法】
mAdapterService.bringUpBle(); 【//2， TurningBleOn】
mAdapterService.startProfileServices(); 【// 5，TurningOn】

状态机的状态流转过程中会先后执行 bringUpBle() 和 startProfileServices()，但此处还没有涉及到这些方法是如何被触发的，后续需要将这些内容连贯起来。

updateAdapterState() 方法是状态机的通用方法。先分析其处理流程，再分析状态机的状态变化流程。

2. Bluetooth StateMachine State Update - updateAdapterState()

packages/apps/Bluetooth/src/com/android/bluetooth/btservice/AdapterService.java

    void updateAdapterState(int prevState, int newState) {
        mAdapterProperties.setState(newState);
        invalidateBluetoothGetStateCache();
        if (mCallbacks != null) {
            int n = mCallbacks.beginBroadcast();
            for (int i = 0; i < n; i++) {
                try {
                    mCallbacks.getBroadcastItem(i).onBluetoothStateChange(prevState, newState);
                } catch (RemoteException e) {
......
                }
            }
            mCallbacks.finishBroadcast();
        }

        // Turn the Adapter all the way off if we are disabling and the snoop log setting changed.
        if (newState == BluetoothAdapter.STATE_BLE_TURNING_ON) {
            mSnoopLogSettingAtEnable =
                    SystemProperties.get(BLUETOOTH_BTSNOOP_LOG_MODE_PROPERTY, "empty");
            mDefaultSnoopLogSettingAtEnable =
                    Settings.Global.getString(getContentResolver(),
                            Settings.Global.BLUETOOTH_BTSNOOP_DEFAULT_MODE);
            SystemProperties.set(BLUETOOTH_BTSNOOP_DEFAULT_MODE_PROPERTY,
                    mDefaultSnoopLogSettingAtEnable);
        } else if (newState == BluetoothAdapter.STATE_BLE_ON
                   && prevState != BluetoothAdapter.STATE_OFF) {
            String snoopLogSetting =
                    SystemProperties.get(BLUETOOTH_BTSNOOP_LOG_MODE_PROPERTY, "empty");
            String snoopDefaultModeSetting =
                    Settings.Global.getString(getContentResolver(),
                            Settings.Global.BLUETOOTH_BTSNOOP_DEFAULT_MODE);

            if (!TextUtils.equals(mSnoopLogSettingAtEnable, snoopLogSetting)
                    || !TextUtils.equals(mDefaultSnoopLogSettingAtEnable,
                            snoopDefaultModeSetting)) {
                mAdapterStateMachine.sendMessage(AdapterState.BLE_TURN_OFF);
            }
        }
    }

3. bringUpBle

packages/apps/Bluetooth/src/com/android/bluetooth/btservice/AdapterService.java

    void bringUpBle() {

        if (getResources().getBoolean(
                R.bool.config_bluetooth_reload_supported_profiles_when_enabled)) {
            Config.init(getApplicationContext());
        }

        mRemoteDevices.reset();
        mAdapterProperties.init(mRemoteDevices);

        mBondStateMachine = BondStateMachine.make(this, mAdapterProperties, mRemoteDevices);

        mJniCallbacks.init(mBondStateMachine, mRemoteDevices);

        try {
            mBatteryStats.noteResetBleScan();
        } catch (RemoteException e) {
            Log.w(TAG, "RemoteException trying to send a reset to BatteryStats");
        }

        // 5 Start Gatt service
        setProfileServiceState(GattService.class, BluetoothAdapter.STATE_ON);
    }

3.1 RemoteDevices

3.2 AdapterProperties

3.3 BondStateMachine

3.4 JniCallbacks

3.5 GattService Initialization

GattService 初始化详情：GattService Initialization
根据 GattService 的基类初始化 ProfileService Initialization 的内容可知，Profile 启动之后，在AdapterService 中会记录状态以及可能会触发后续的蓝牙enable 流程。

packages/apps/Bluetooth/src/com/android/bluetooth/btservice/AdapterService.java

public class AdapterService extends Service {

        private void processProfileServiceStateChanged(ProfileService profile, int state) {
            switch (state) {
                case BluetoothAdapter.STATE_ON:
                    ......
                    if (GattService.class.getSimpleName().equals(profile.getName())) {
                        // 启动 GATT service 时，走该分支，继续执行 enable
                        enableNative();
                    } else if (mRegisteredProfiles.size() == Config.getSupportedProfiles().length
                            && mRegisteredProfiles.size() == mRunningProfiles.size()) {
                        // 所有支持的 profile service 启动后，走该分支
                        ......
                    }
                    break;
                    ......
            }
        }
    }
}

以上代码内容，不仅是 ProfileService 的通用流程，还是蓝牙enable的整体流程的内容。

若 GattService 启动完成，则执行 enableNative()，详情：Bluetooth initialization - enable in Bluetooth process - Native(Cpp) ；
若所有支持的 profile 启动完成，则执行另外一个分支，具体内容在下文介绍。

4. startProfileServices

    void startProfileServices() {
        Class[] supportedProfileServices = Config.getSupportedProfiles();
        if (supportedProfileServices.length == 1 && GattService.class.getSimpleName()
                .equals(supportedProfileServices[0].getSimpleName())) {
             ...... // 设备只支持 BLE 时走这里，不分析此路径
        } else {
            setAllProfileServiceStates(supportedProfileServices, BluetoothAdapter.STATE_ON);
        }
    }

    private void setAllProfileServiceStates(Class[] services, int state) {
        for (Class service : services) {
            if (GattService.class.getSimpleName().equals(service.getSimpleName())) {
                continue;  // GattService 已经初始化过了，排除之
            }
            setProfileServiceState(service, state);
        }
    }

01-15 21:33:43.404 31081 31081 V AdapterServiceConfig: Adding HeadsetService
01-15 21:33:43.404 31081 31081 V AdapterServiceConfig: Adding A2dpService
01-15 21:33:43.404 31081 31081 V AdapterServiceConfig: Adding HidHostService
01-15 21:33:43.404 31081 31081 V AdapterServiceConfig: Adding PanService
01-15 21:33:43.404 31081 31081 V AdapterServiceConfig: Adding GattService
01-15 21:33:43.404 31081 31081 V AdapterServiceConfig: Adding BluetoothMapService
01-15 21:33:43.404 31081 31081 V AdapterServiceConfig: Adding AvrcpTargetService
01-15 21:33:43.404 31081 31081 V AdapterServiceConfig: Adding SapService
01-15 21:33:43.404 31081 31081 V AdapterServiceConfig: Adding HidDeviceService
01-15 21:33:43.404 31081 31081 V AdapterServiceConfig: Adding BluetoothOppService
01-15 21:33:43.404 31081 31081 V AdapterServiceConfig: Adding BluetoothPbapService
01-15 21:33:43.404 31081 31081 V AdapterServiceConfig: Adding HearingAidService

当所有支持的 Profile 全部注册并启动之后，执行
packages/apps/Bluetooth/src/com/android/bluetooth/btservice/AdapterService.java

public class AdapterService extends Service {

        private void processProfileServiceStateChanged(ProfileService profile, int state) {
            switch (state) {
                case BluetoothAdapter.STATE_ON:
                    ......
                    if (GattService.class.getSimpleName().equals(profile.getName())) {
                        // 启动 GATT service 时，走该分支，继续执行 enable
                        ......
                    } else if (mRegisteredProfiles.size() == Config.getSupportedProfiles().length
                            && mRegisteredProfiles.size() == mRunningProfiles.size()) {
                        // 所有支持的 profile service 启动后，走该分支
                        mAdapterProperties.onBluetoothReady();
                        updateUuids();
                        setBluetoothClassFromConfig();
                        initProfileServices();
                        getAdapterPropertyNative(AbstractionLayer.BT_PROPERTY_LOCAL_IO_CAPS);
                        getAdapterPropertyNative(AbstractionLayer.BT_PROPERTY_LOCAL_IO_CAPS_BLE);
                        mAdapterStateMachine.sendMessage(AdapterState.BREDR_STARTED);
                    }
                    break;
                    ......
            }
        }
    }
}

若所有支持的 profile 启动完成，则执行一些其他的初始化操作。
随后向状态机发送 BREDR_STARTED 消息，状态机进入 OnState。

5. Summary

经过以上分析，蓝牙初始化整体架构如下图：

Android Bluetooth Enable Arch

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