纯C++binder服务和客户端实例

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IHelloService.h

/* 参考: frameworks\av\include\media\IMediaPlayerService.h */

#ifndef ANDROID_IHELLOERVICE_H
#define ANDROID_IHELLOERVICE_H

#include <utils/Errors.h>  // for status_t
#include <utils/KeyedVector.h>
#include <utils/RefBase.h>
#include <utils/String8.h>
#include <binder/IInterface.h>
#include <binder/Parcel.h>

#define HELLO_SVR_CMD_SAYHELLO     0
#define HELLO_SVR_CMD_SAYHELLO_TO  1

namespace android {

class IHelloService: public IInterface
{
public:
    DECLARE_META_INTERFACE(HelloService);
    virtual void sayhello(void) = 0;
    virtual int sayhello_to(const char *name) = 0;
};

class BnHelloService: public BnInterface<IHelloService>
{
public:
    virtual status_t    onTransact( uint32_t code,
                                    const Parcel& data,
                                    Parcel* reply,
                                    uint32_t flags = 0);

    virtual void sayhello(void);
    virtual int sayhello_to(const char *name);
};
}

#endif

BnHelloService.cpp

/* 参考: frameworks\av\media\libmedia\IMediaPlayerService.cpp */

#define LOG_TAG "HelloService"
#include "IHelloService.h"

namespace android {

status_t BnHelloService::onTransact( uint32_t code, const Parcel& data,
                                Parcel* reply, uint32_t flags)
{
    /* 解析数据,调用sayhello/sayhello_to */

    switch (code) {
        case HELLO_SVR_CMD_SAYHELLO: {
            sayhello();
            return NO_ERROR;
        } break;
        
        case HELLO_SVR_CMD_SAYHELLO_TO: {
            /* 从data中取出参数 */
            int32_t policy =  data.readInt32(); //多余的0，客户端有多发送一个0
            String16 name16 = data.readString16(); //获取客户端发来的name
            String8 name8(name16); //讲16位字符传化位8位的字符
            int cnt = sayhello_to(name8.string()); //const char*
            /* 把返回值写入reply传回去 */
            reply->writeInt32(cnt);
            return NO_ERROR;
        } break;
        default:
            return BBinder::onTransact(code, data, reply, flags);
    }
}

void BnHelloService::sayhello(void)
{
    static int cnt = 0;
    printf("say hello : %d\n", cnt++);
}

int BnHelloService::sayhello_to(const char *name)
{
    static int cnt = 0;
    printf("say hello to %s : %d\n", name, cnt++);
    return cnt;
}
}

BpHelloService.cpp

/* 参考: frameworks\av\media\libmedia\IMediaPlayerService.cpp */
#include "IHelloService.h"
namespace android {

class BpHelloService: public BpInterface<IHelloService>
{
public:
    BpHelloService(const sp<IBinder>& impl)
        : BpInterface<IHelloService>(impl)
    {
    }

    void sayhello(void)
    {
        /* 构造/发送数据 */
        Parcel data, reply;
        data.writeInt32(0);
        remote()->transact(HELLO_SVR_CMD_SAYHELLO, data, &reply);
    }
    
    int sayhello_to(const char *name)
    {
        /* 构造/发送数据 */
        Parcel data, reply;

        data.writeInt32(0); //多发一个0
        data.writeString16(String16(name));

        remote()->transact(HELLO_SVR_CMD_SAYHELLO_TO, data, &reply);

        return reply.readInt32();
    }

};

IMPLEMENT_META_INTERFACE(HelloService, "android.media.IHelloService");

}

test_service.cpp

/* 参考: frameworks\av\media\mediaserver\Main_mediaserver.cpp */

#define LOG_TAG "HelloService"
//#define LOG_NDEBUG 0

#include <fcntl.h>
#include <sys/prctl.h>
#include <sys/wait.h>
#include <binder/IPCThreadState.h>
#include <binder/ProcessState.h>
#include <binder/IServiceManager.h>
#include <cutils/properties.h>
#include <utils/Log.h>
#include "IHelloService.h"
using namespace android;

int main(void)
{
    /* addService */

    /* while(1){ read data, 解析数据, 调用服务函数 } */

    /* 打开驱动, mmap */
    sp<ProcessState> proc(ProcessState::self());

    /* 获得BpServiceManager */
    sp<IServiceManager> sm = defaultServiceManager();

    sm->addService(String16("hello"), new BnHelloService());

    /* 循环体 */
    ProcessState::self()->startThreadPool();
    IPCThreadState::self()->joinThreadPool();

    return 0;
}

test_client.cpp

#define LOG_TAG "HelloService"
#include <fcntl.h>
#include <sys/prctl.h>
#include <sys/wait.h>
#include <binder/IPCThreadState.h>
#include <binder/ProcessState.h>
#include <binder/IServiceManager.h>
#include <cutils/properties.h>
#include <utils/Log.h>
#include "IHelloService.h"

using namespace android;

/* ./test_client hello
 * ./test_client hello <name>
 */
int main(int argc, char **argv)
{
    int cnt;
    
    if (argc < 2){
        printf("Usage:\n");
        printf("%s hello\n", argv[0]);
        printf("%s hello <name>\n", argv[0]);
        return -1;
    }

    /* getService */
    /* 打开驱动, mmap */
    sp<ProcessState> proc(ProcessState::self());

    /* 获得BpServiceManager */
    sp<IServiceManager> sm = defaultServiceManager();
    //获取hello服务
    sp<IBinder> binder = sm->getService(String16("hello"));

    if (binder == 0)
    {
        printf("can't get hello service\n");
        return -1;
    }

    /* service肯定是BpHelloServie指针 */
    sp<IHelloService> service = interface_cast<IHelloService>(binder);

    /* 调用Service的函数 */
    if (argc < 3) {
        service->sayhello();
        printf("client call sayhello");
    }
    else {
        cnt = service->sayhello_to(argv[2]);
        printf("client call sayhello_to, cnt = %d", cnt);
    }
    
    return 0;
}

Andriod.mk

LOCAL_PATH:= $(call my-dir)

include $(CLEAR_VARS)

LOCAL_SRC_FILES:= \
    BnHelloService.cpp \
    BpHelloService.cpp \
    test_server.cpp

LOCAL_SHARED_LIBRARIES := \
    libcutils \
    libutils \
    liblog \
    libbinder 

LOCAL_MODULE:= test_server
LOCAL_32_BIT_ONLY := true

include $(BUILD_EXECUTABLE)

include $(CLEAR_VARS)

LOCAL_SRC_FILES:= \
    BpHelloService.cpp \
    test_client.cpp

LOCAL_SHARED_LIBRARIES := \
    libcutils \
    libutils \
    liblog \
    libbinder 
    
LOCAL_MODULE:= test_client
LOCAL_32_BIT_ONLY := true

include $(BUILD_EXECUTABLE)