C++ binder demo

binder_client.cpp

#include <binder/IServiceManager.h>
#include <binder/IBinder.h>
#include <binder/Parcel.h>
#include <binder/ProcessState.h>
#include <binder/IPCThreadState.h>
#include <binder/IInterface.h>
#include <binder/Parcel.h>
#include <binder/Binder.h>

//#include <utils/Log.h>

using namespace android;

#ifdef LOG_TAG
#undef LOG_TAG
#endif

#define LOG_TAG "BINDER_SERVICE"
#define BINDER_SERVICE "binder_server_end"
#define BINDER_CALLBACK "binder_callback"

#define FIRST_CODE 1
#define CALLBACK_CODE 2

class ClientCallback : public BBinder
{
public: 
    ClientCallback()
    {
        ALOGE("zach ClientCallback initialized");
        desc = String16(BINDER_CALLBACK);
        
    }

    virtual ~ClientCallback() {}

    virtual const String16& getInterfaceDescriptor() const {
        return desc;
    }

protected:
    virtual status_t onTransact(uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags = 0) {
        ALOGD("zach Client onTransact, line: %d, code: %d", __LINE__, code);

        int v1, v2, v3;
        String8 s1, s2, s3;

        switch (code)
        {
        case CALLBACK_CODE:
            v1 = data.readInt32();
            v2 = data.readInt32();
            v3 = data.readInt32();

            ALOGE("zach Client %d, read v1: %d", __LINE__, v1);
            ALOGE("zach Client %d, read v2: %d", __LINE__, v2);
            ALOGE("zach Client %d, read v3: %d", __LINE__, v3);

            s1 = data.readString8();
            s2 = data.readString8();
            s3 = data.readString8();

            ALOGE("zach Client %d, read String s1: %s", __LINE__, s1.string());
            ALOGE("zach Client %d, read String s2: %s", __LINE__, s2.string());
            ALOGE("zach Client %d, read String s3: %s", __LINE__, s3.string());

            break;
        
        default:
            return BBinder::onTransact(code, data, reply, flags);
        }
        return 0;
    }


private:
    String16 desc;
};


int main() {
    sp<IServiceManager> sm = defaultServiceManager();
    sp<IBinder> iBinder = sm->getService(String16(BINDER_SERVICE));
    if (iBinder == nullptr) {
        ALOGW("zach Can't find binder service");
        return -1;
    }

    Parcel _data, _reply;
    ClientCallback *callback = new ClientCallback();

    _data.writeStrongBinder(sp<IBinder>(callback));
    _data.writeInterfaceToken(String16(BINDER_CALLBACK));

    int ret = iBinder->transact(FIRST_CODE, _data, &_reply, 0);
    ALOGI("zach Client transact ret: %d", ret);
    IPCThreadState::self()->joinThreadPool();
    ALOGI("zach Client joinThreadPool complete");

    return 0;
}

binder_server.cpp

#include <binder/IServiceManager.h>
#include <binder/IBinder.h>
#include <binder/Parcel.h>
#include <binder/ProcessState.h>
#include <binder/IPCThreadState.h>

//#include <utils/Log.h>

using namespace android;

#ifdef LOG_TAG
#undef LOG_TAG
#endif

#define LOG_TAG "BINDER_SERVICE"
#define BINDER_SERVICE "binder_server_end"
#define BINDER_CALLBACK "binder_callback"

#define FIRST_CODE 1
#define CALLBACK_CODE 2

class BinderService : public BBinder {
public:
    BinderService() {
        ALOGE("zach BinderService server started");
        desc = String16(BINDER_SERVICE);
        
    }

    virtual ~BinderService() {}

    virtual const String16& getInterfaceDescriptor() const { 
        return desc; 
    }

protected:
    virtual status_t onTransact(uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags = 0) {
        ALOGD("zach Server onTrancat, line = %d, code = %d", __LINE__, code);

        switch (code)
        {
        case FIRST_CODE:
            callback = data.readStrongBinder();
            if (callback != NULL) {
                Parcel _data, _reply;
                _data.writeInt32(1);
                _data.writeInt32(3);
                _data.writeInt32(5);

                _data.writeString8(String8("I"));
                _data.writeString8(String8("am"));
                _data.writeString8(String8("here"));

                int ret = callback->transact(CALLBACK_CODE, _data, &_reply, 0);
                ALOGI("zach Server callback transact ret: %d", ret);
            }

            data.enforceInterface(u"binder_callback", true);   // corresponding to writeInterfaceToken()
            ALOGD("zach Service write callback to client, line: %d", __LINE__);
            break;

        default:
            return BBinder::onTransact(code, data, reply, flags);
        }

        return 0;
    }

private:
    String16 desc;
    sp<IBinder> callback;
};


int main() {
    sp<IServiceManager> sm = defaultServiceManager();
    BinderService* binderServer = new BinderService();
    status_t ret = sm->addService(String16(BINDER_SERVICE), binderServer);
    ALOGD("zach add Binder service to service manager, ret = %d", ret);

    IPCThreadState::self()->joinThreadPool(true);

    ALOGD("zach IPCThreadState joinThreadPool end");
    return 0;
}

C++ binder demo_Android.mk

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_SRC_FILES := binder_client.cpp
LOCAL_SHARED_LIBRARIES := liblog libcutils libbinder libutils
LOCAL_MODULE := binder_client
include $(BUILD_EXECUTABLE)


include $(CLEAR_VARS)
LOCAL_SRC_FILES := binder_server.cpp
LOCAL_SHARED_LIBRARIES := liblog libcutils libbinder libutils 
LOCAL_MODULE := binder_server
include $(BUILD_EXECUTABLE)

log

adb shell logcat -c ; adb shell logcat |grep BINDER_SERVICE

11-26 11:04:23.719  4876  4876 E BINDER_SERVICE: zach BinderService server started
11-26 11:04:23.720  4876  4876 D BINDER_SERVICE: zach add Binder service to service manager, ret = 0

11-26 11:04:30.581  4889  4889 E BINDER_SERVICE: zach ClientCallback initialized
11-26 11:04:30.589  4876  4876 D BINDER_SERVICE: zach Server onTrancat, line = 38, code = 1
11-26 11:04:30.589  4889  4889 D BINDER_SERVICE: zach Client onTransact, line: 43, code: 2
11-26 11:04:30.589  4889  4889 E BINDER_SERVICE: zach Client 55, read v1: 1
11-26 11:04:30.589  4889  4889 E BINDER_SERVICE: zach Client 56, read v2: 3
11-26 11:04:30.589  4889  4889 E BINDER_SERVICE: zach Client 57, read v3: 5
11-26 11:04:30.589  4889  4889 E BINDER_SERVICE: zach Client 63, read String s1: I
11-26 11:04:30.589  4889  4889 E BINDER_SERVICE: zach Client 64, read String s2: am
11-26 11:04:30.589  4889  4889 E BINDER_SERVICE: zach Client 65, read String s3: here
11-26 11:04:30.589  4876  4876 I BINDER_SERVICE: zach Server callback transact ret: 0
11-26 11:04:30.589  4876  4876 D BINDER_SERVICE: zach Service write callback to client, line: 59
11-26 11:04:30.589  4889  4889 I BINDER_SERVICE: zach Client transact ret: 0