Native層怎樣獲得wakelock

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1. 定義一個接口類

frameworks/native/include/powermanager/IPowerManager.h

// must be kept in sync with interface defined in IPowerManager.aidl

class IPowerManager : public IInterface

{

public:

    DECLARE_META_INTERFACE(PowerManager);

    // FIXME remove the bool isOneWay parameters as they are not oneway in the .aidl

    virtual status_t acquireWakeLock(int flags, const sp<IBinder>& lock, const String16& tag,

            const String16& packageName, bool isOneWay = false) = 0;

    virtual status_t acquireWakeLockWithUid(int flags, const sp<IBinder>& lock, const String16& tag,

            const String16& packageName, int uid, bool isOneWay = false) = 0;

    virtual status_t releaseWakeLock(const sp<IBinder>& lock, int flags, bool isOneWay = false) = 0;

    virtual status_t updateWakeLockUids(const sp<IBinder>& lock, int len, const int *uids,

            bool isOneWay = false) = 0;

    // oneway in the .aidl

    virtual status_t powerHint(int hintId, int data) = 0;

};

1]

service是: power: [android.os.IPowerManager],是以這裡的接口類名為： IPowerManager

且DECLARE_META_INTERFACE(PowerManager)的宏變量是：PowerManager

[email protected]:/ $ service list | grep power                                     

power: [android.os.IPowerManager]

2]

和服務層的 aidl是怎樣對應的？參數對應還是順序？

interface IPowerManager

{

    // WARNING: The first five methods must remain the first five methods because their

    // transaction numbers must not change unless IPowerManager.cpp is also updated.

    void acquireWakeLock(IBinder lock, int flags, String tag, String packageName, in WorkSource ws,

            String historyTag);

    void acquireWakeLockWithUid(IBinder lock, int flags, String tag, String packageName,

            int uidtoblame);

    void releaseWakeLock(IBinder lock, int flags);

    void updateWakeLockUids(IBinder lock, in int[] uids);

    oneway void powerHint(int hintId, int data);

}

2. 實作接口類 BpPowerManager

以新定義的接口類為模闆參數

// must be kept in sync with IPowerManager.aidl

enum {

    ACQUIRE_WAKE_LOCK = IBinder::FIRST_CALL_TRANSACTION,

    ACQUIRE_WAKE_LOCK_UID = IBinder::FIRST_CALL_TRANSACTION + 1,

    RELEASE_WAKE_LOCK = IBinder::FIRST_CALL_TRANSACTION + 2,

    UPDATE_WAKE_LOCK_UIDS = IBinder::FIRST_CALL_TRANSACTION + 3,

    POWER_HINT = IBinder::FIRST_CALL_TRANSACTION + 4,

};

class BpPowerManager : public BpInterface<IPowerManager>

{

public:

    BpPowerManager(const sp<IBinder>& impl)

        : BpInterface<IPowerManager>(impl)

    {

    }

}

實作上面的接口函數，就是調用service提供的接口：

    virtual status_t acquireWakeLock(int flags, const sp<IBinder>& lock, const String16& tag,

            const String16& packageName, bool isOneWay)

    {

        Parcel data, reply;

        data.writeInterfaceToken(IPowerManager::getInterfaceDescriptor());

        data.writeStrongBinder(lock);

        data.writeInt32(flags);

        data.writeString16(tag);

        data.writeString16(packageName);

        data.writeInt32(0); // no WorkSource

        data.writeString16(NULL, 0); // no history tag

        return remote()->transact(ACQUIRE_WAKE_LOCK, data, &reply,

                isOneWay ? IBinder::FLAG_ONEWAY : 0);

    }

對應的java函數是：

從這裡可以看出，聲明的接口參數可以不一緻，調用服務時參數要和服務側的處理函數一緻

        @Override // Binder call

        public void acquireWakeLock(IBinder lock, int flags, String tag, String packageName,

                WorkSource ws, String historyTag) {

}

這裡沒有找到接收請求，再分發的代碼？

3.

請求服務的native代理端，實作為

LOCAL_PATH:= $(call my-dir)

include $(CLEAR_VARS)

LOCAL_SRC_FILES:= \

    IPowerManager.cpp

LOCAL_SHARED_LIBRARIES := \

    libutils \

    libbinder

LOCAL_MODULE:= libpowermanager

LOCAL_MODULE_TAGS := optional

LOCAL_CFLAGS += -Wall -Werror -Wunused -Wunreachable-code

include $(BUILD_SHARED_LIBRARY)

4.

怎樣通過新生成的類使用java的服務

 sp<IBinder> binder = defaultServiceManager()->checkService(String16("power"));

 mPowerManager = interface_cast<IPowerManager>(binder);

mPowerManager->acquireWakeLock(

                    POWERMANAGER_PARTIAL_WAKE_LOCK,

                    binder,

String16("AWakeLock"), 

String16("media"));

這裡是一緻的

acquireWakeLock(int flags, 

const sp<IBinder>& lock, 

const String16& tag,

            const String16& packageName);

如果代碼中已經有１－－３的實作，直接使用４即可