场景介绍
IPC的主要工作是让运行在不同进程的Proxy和Stub互相通信,而IPC CAPI是提供的C接口。 IPC CAPI接口不直接提供跨进程通信能力,两个进程之间的IPC通道建立,依赖于 Ability Kit 。

接口说明
表1 CAPI侧IPC接口
接口名 | 描述 |
---|---|
typedef int (*OH_OnRemoteRequestCallback)(uint32_t code, const OHIPCParcel *data, OHIPCParcel *reply,void *userData); | Stub端用于处理远端数据请求的回调函数。 |
OHIPCRemoteStub* OH_IPCRemoteStub_Create(const char *descriptor, OH_OnRemoteRequestCallback requestCallback,OH_OnRemoteDestroyCallback destroyCallback, void *userData); | 创建OHIPCRemoteStub对象。 |
int OH_IPCRemoteProxy_SendRequest(const OHIPCRemoteProxy *proxy,uint32_t code, const OHIPCParcel *data, OHIPCParcel *reply,const OH_IPC_MessageOption *option); | IPC消息发送函数。 |
struct OHIPCRemoteProxy; | OHIPCRemoteProxy对象,用于向远端发送请求。需要依赖元能力接口返回。 |
OHIPCDeathRecipient* OH_IPCDeathRecipient_Create(OH_OnDeathRecipientCallback deathRecipientCallback,OH_OnDeathRecipientDestroyCallback destroyCallback,void *userData); | 创建远端OHIPCRemoteStub对象死亡通知对象OHIPCDeathRecipient。 |
int OH_IPCRemoteProxy_AddDeathRecipient(OHIPCRemoteProxy *proxy,OHIPCDeathRecipient *recipient); | 向OHIPCRemoteProxy对象添加死亡监听,用于接收远端OHIPCRemoteStub对象死亡的回调通知。 |
开发步骤
以下步骤描述了如何使用 IPCKit 提供的CAPI接口,创建远端Stub和使用客户端代理Proxy进行通信,同时兼备远端死亡通知接收能力。
1. 添加动态链接库
CMakeLists.txt中添加以下lib。
txt
# ipc capi
libipc_capi.so
# 元能力,ability capi
libchild_process.so
2. 头文件
c++
// ipc capi
#include <IPCKit/ipc_kit.h>
// 元能力,ability capi
#include <AbilityKit/native_child_process.h>
3. 异步调用场景
3.1 公共数据及函数定义
c++
#include <string>
#include <thread>
#include <mutex>
#include <chrono>
#include <condition_variable>
#include <IPCKit/ipc_kit.h>
#include <AbilityKit/native_child_process.h>
#include <hilog/log.h>
#undef LOG_DOMAIN
#undef LOG_TAG
#define LOG_DOMAIN 0x0201
#define LOG_TAG "IPCCApiSample"
enum RequestCode {
ASYNC_ADD_CODE = 1,
REQUEST_EXIT_CODE = 2,
OTHER_CODE
};
static constexpr int MAX_MEMORY_SIZE = 204800;
static const std::string INTERFACE_DESCRIPTOR = "INTERFACE_DESCRIPTOR";
static const std::string NATIVE_REMOTE_STUB_TEST_TOKEN = "native.remote.stub";
static const std::string NATIVE_REMOTE_STUB_ASYNC_CALL_TEST_TOKEN = "native.remote.stub.async.call";
// 定义内存分配函数
static void* LocalMemoryAllocator(int32_t len) {
if (len < 0 || len > MAX_MEMORY_SIZE ) {
return nullptr;
}
void *buffer = malloc(len);
if (buffer == nullptr) {
return nullptr;
}
memset(buffer, 0, len);
return buffer;
}
3.2 服务端对象: IpcCApiStubTest
c++
class IpcCApiStubTest {
public:
explicit IpcCApiStubTest();
~IpcCApiStubTest();
void MainProc();
OHIPCRemoteStub* GetRemoteStub();
static int OnRemoteRequest(uint32_t code, const OHIPCParcel *data, OHIPCParcel *reply, void *userData);
private:
int AsyncAdd(const OHIPCParcel *data);
int RequestExitChildProcess();
private:
OHIPCRemoteStub *stub_{ nullptr };
std::mutex childMutex_;
std::condition_variable childCondVar_;
};
IpcCApiStubTest::IpcCApiStubTest() {
stub_ = OH_IPCRemoteStub_Create(INTERFACE_DESCRIPTOR.c_str(), &IpcCApiStubTest::OnRemoteRequest,
nullptr, this);
}
IpcCApiStubTest::~IpcCApiStubTest() {
if (stub_ != nullptr) {
OH_IPCRemoteStub_Destroy(stub_);
}
}
void IpcCApiStubTest::MainProc() {
std::unique_lock<std::mutex> autoLock(childMutex_);
childCondVar_.wait(autoLock);
}
OHIPCRemoteStub* IpcCApiStubTest::GetRemoteStub() {
return stub_;
}
int IpcCApiStubTest::OnRemoteRequest(uint32_t code, const OHIPCParcel *data, OHIPCParcel *reply, void *userData) {
int readLen = 0;
char *token = nullptr;
// 接口校验
if (OH_IPCParcel_ReadInterfaceToken(data, &token, &readLen, LocalMemoryAllocator) != OH_IPC_SUCCESS
|| NATIVE_REMOTE_STUB_TEST_TOKEN != token) {
if (token != nullptr) {
OH_LOG_ERROR(LOG_APP, "check InterfaceToken failed");
free(token);
}
return OH_IPC_PARCEL_WRITE_ERROR;
}
free(token);
auto *stubTest = reinterpret_cast<IpcCApiStubTest *>(userData);
if (stubTest == nullptr) {
return OH_IPC_CHECK_PARAM_ERROR;
}
auto rqCode = RequestCode(code);
switch (rqCode) {
case ASYNC_ADD_CODE: {
return stubTest->AsyncAdd(data);
}
case REQUEST_EXIT_CODE: {
return stubTest->RequestExitChildProcess();
}
default:
break;
}
return OH_IPC_SUCCESS;
}
int IpcCApiStubTest::AsyncAdd(const OHIPCParcel *data) {
int a = 0;
int b = 0;
OH_LOG_INFO(LOG_APP, "start async add a=%d,b=%d", a, b);
if ((OH_IPCParcel_ReadInt32(data, &a) != OH_IPC_SUCCESS)
|| (OH_IPCParcel_ReadInt32(data, &b) != OH_IPC_SUCCESS)) {
return OH_IPC_PARCEL_READ_ERROR;
}
auto proxyCallBack = OH_IPCParcel_ReadRemoteProxy(data);
if (proxyCallBack == nullptr) {
return OH_IPC_PARCEL_READ_ERROR;
}
OH_LOG_INFO(LOG_APP, "start create sendCallBack thread!");
// 此处开启线程异步完成功能实现并利用proxyCallBack完成结果响应,如果同步调用,则直接通过replyData写入响应结果即可
std::thread th([proxyCallBack, a, b] {
auto data = OH_IPCParcel_Create();
if (data == nullptr) {
OH_IPCRemoteProxy_Destroy(proxyCallBack);
return;
}
auto reply = OH_IPCParcel_Create();
if (reply == nullptr) {
OH_IPCParcel_Destroy(data);
OH_IPCRemoteProxy_Destroy(proxyCallBack);
return;
}
if (OH_IPCParcel_WriteInt32(data, a + b) != OH_IPC_SUCCESS) {
OH_IPCParcel_Destroy(data);
OH_IPCParcel_Destroy(reply);
OH_IPCRemoteProxy_Destroy(proxyCallBack);
return;
}
// 异步线程处理结果通过IPC同步调用方式返回给业务请求方
OH_IPC_MessageOption option = { OH_IPC_REQUEST_MODE_SYNC, 0 };
OH_LOG_INFO(LOG_APP, "thread start sendCallBack!");
int ret = OH_IPCRemoteProxy_SendRequest(proxyCallBack, ASYNC_ADD_CODE, data, reply, &option);
OH_LOG_INFO(LOG_APP, "thread sendCallBack ret = %d", ret);
if (ret != OH_IPC_SUCCESS) {
OH_IPCParcel_Destroy(data);
OH_IPCParcel_Destroy(reply);
OH_IPCRemoteProxy_Destroy(proxyCallBack);
return;
}
OH_IPCRemoteProxy_Destroy(proxyCallBack);
OH_IPCParcel_Destroy(data);
OH_IPCParcel_Destroy(reply);
});
th.detach();
return OH_IPC_SUCCESS;
}
int IpcCApiStubTest::RequestExitChildProcess() {
std::unique_lock<std::mutex> autoLock(childMutex_);
childCondVar_.notify_all();
return OH_IPC_SUCCESS;
}
3.3 客户端代理对象: IpcCApiProxyTest
cpp
// 用戶自定义错误码
static constexpr int OH_IPC_CREATE_OBJECT_ERROR = OH_IPC_USER_ERROR_CODE_MIN + 1;
class IpcCApiProxyTest {
public:
explicit IpcCApiProxyTest(OHIPCRemoteProxy *proxy);
~IpcCApiProxyTest();
public:
int AsyncAdd(int a, int b, int &result);
int RequestExitChildProcess();
void ClearResource();
private:
void SendAsyncReply(int &replyValue);
int WaitForAsyncReply(int timeOut);
static int OnRemoteRequest(uint32_t code, const OHIPCParcel *data,
OHIPCParcel *reply, void *userData);
static void OnDeathRecipientCB(void *userData);
private:
int asyncReply_{};
std::mutex mutex_;
std::condition_variable cv_;
OHIPCRemoteProxy *proxy_{ nullptr };
OHIPCRemoteStub *replyStub_{ nullptr };
OHIPCDeathRecipient *deathRecipient_{ nullptr };
};
IpcCApiProxyTest::IpcCApiProxyTest(OHIPCRemoteProxy *proxy) {
if (proxy == nullptr) {
OH_LOG_ERROR(LOG_APP, "proxy is nullptr");
return;
}
proxy_ = proxy;
replyStub_ = OH_IPCRemoteStub_Create(NATIVE_REMOTE_STUB_ASYNC_CALL_TEST_TOKEN.c_str(), OnRemoteRequest,
nullptr, this);
if (replyStub_ == nullptr) {
OH_LOG_ERROR(LOG_APP, "crete reply stub failed!");
return;
}
deathRecipient_ = OH_IPCDeathRecipient_Create(OnDeathRecipientCB, nullptr, this);
if (deathRecipient_ == nullptr) {
OH_LOG_ERROR(LOG_APP, "OH_IPCDeathRecipient_Create failed!");
return;
}
OH_IPCRemoteProxy_AddDeathRecipient(proxy_, deathRecipient_);
}
IpcCApiProxyTest::~IpcCApiProxyTest() {
if (proxy_ != nullptr) {
OH_IPCRemoteProxy_Destroy(proxy_);
}
if (deathRecipient_ != nullptr) {
OH_IPCDeathRecipient_Destroy(deathRecipient_);
}
if (replyStub_ != nullptr) {
OH_IPCRemoteStub_Destroy(replyStub_);
}
}
int IpcCApiProxyTest::AsyncAdd(int a, int b, int &result) {
OH_LOG_INFO(LOG_APP, "start %d + %d", a, b);
auto data = OH_IPCParcel_Create();
if (data == nullptr) {
return OH_IPC_CREATE_OBJECT_ERROR;
}
// 写入接口校验token
if (OH_IPCParcel_WriteInterfaceToken(data, NATIVE_REMOTE_STUB_TEST_TOKEN.c_str()) != OH_IPC_SUCCESS) {
OH_LOG_ERROR(LOG_APP, "OH_IPCParcel_WriteInterfaceToken failed!");
OH_IPCParcel_Destroy(data);
return OH_IPC_PARCEL_WRITE_ERROR;
}
if (OH_IPCParcel_WriteInt32(data, a) != OH_IPC_SUCCESS
|| OH_IPCParcel_WriteInt32(data, b) != OH_IPC_SUCCESS
|| OH_IPCParcel_WriteRemoteStub(data, replyStub_) != OH_IPC_SUCCESS) {
OH_IPCParcel_Destroy(data);
return OH_IPC_PARCEL_WRITE_ERROR;
}
// 异步发送使用replyStub_进行响应结果接收,异步处理需要写入用于接收结果的OHIPCRemoteStub对象
OH_IPC_MessageOption option = { OH_IPC_REQUEST_MODE_ASYNC, 0 };
int ret = OH_IPCRemoteProxy_SendRequest(proxy_, RequestCode::ASYNC_ADD_CODE, data, nullptr, &option);
if (ret != OH_IPC_SUCCESS) {
OH_IPCParcel_Destroy(data);
OH_LOG_ERROR(LOG_APP, "OH_IPCRemoteProxy_SendRequest failed!");
return ret;
}
static constexpr int TIMEOUT = 3;
WaitForAsyncReply(TIMEOUT);
OH_LOG_INFO(LOG_APP, "asyncReply_:%d", asyncReply_);
result = asyncReply_;
OH_IPCParcel_Destroy(data);
return OH_IPC_SUCCESS;
}
int IpcCApiProxyTest::RequestExitChildProcess() {
auto data = OH_IPCParcel_Create();
if (data == nullptr) {
return OH_IPC_CREATE_OBJECT_ERROR;
}
auto reply = OH_IPCParcel_Create();
if (reply == nullptr) {
OH_IPCParcel_Destroy(data);
return OH_IPC_CREATE_OBJECT_ERROR;
}
if (OH_IPCParcel_WriteInterfaceToken(data, NATIVE_REMOTE_STUB_TEST_TOKEN.c_str()) != OH_IPC_SUCCESS) {
OH_LOG_ERROR(LOG_APP, "OH_IPCParcel_WriteInterfaceToken failed!");
OH_IPCParcel_Destroy(data);
OH_IPCParcel_Destroy(reply);
return OH_IPC_PARCEL_WRITE_ERROR;
}
OH_IPC_MessageOption option = { OH_IPC_REQUEST_MODE_SYNC, 0 };
int ret = OH_IPCRemoteProxy_SendRequest(proxy_, RequestCode::REQUEST_EXIT_CODE, data, reply, &option);
if (ret != OH_IPC_SUCCESS) {
OH_IPCParcel_Destroy(data);
OH_IPCParcel_Destroy(reply);
OH_LOG_ERROR(LOG_APP, "OH_IPCRemoteProxy_SendRequest failed!");
return ret;
}
OH_IPCParcel_Destroy(data);
OH_IPCParcel_Destroy(reply);
return OH_IPC_SUCCESS;
}
void IpcCApiProxyTest::SendAsyncReply(int &replyValue) {
std::unique_lock<std::mutex> lck(mutex_);
asyncReply_ = replyValue;
cv_.notify_all();
}
int IpcCApiProxyTest::WaitForAsyncReply(int timeOut) {
asyncReply_ = 0;
std::unique_lock<std::mutex> lck(mutex_);
cv_.wait_for(lck, std::chrono::seconds(timeOut), [&] {
return asyncReply_ != 0;
});
return asyncReply_;
}
int IpcCApiProxyTest::OnRemoteRequest(uint32_t code, const OHIPCParcel *data,
OHIPCParcel *reply, void *userData) {
OH_LOG_INFO(LOG_APP, "start %u", code);
auto *proxyTest = reinterpret_cast<IpcCApiProxyTest *>(userData);
if (proxyTest == nullptr || code != static_cast<uint32_t>(RequestCode::ASYNC_ADD_CODE)) {
OH_LOG_ERROR(LOG_APP, "check param failed!");
return OH_IPC_CHECK_PARAM_ERROR;
}
int32_t val = -1;
if (OH_IPCParcel_ReadInt32(data, &val) != OH_IPC_SUCCESS) {
OH_LOG_ERROR(LOG_APP, "OH_IPCParcel_ReadInt32 failed!");
return OH_IPC_PARCEL_READ_ERROR;
}
proxyTest->SendAsyncReply(val);
return OH_IPC_SUCCESS;
}
void IpcCApiProxyTest::ClearResource() {
// clear resource;
}
void IpcCApiProxyTest::OnDeathRecipientCB(void *userData) {
auto *proxyTest = reinterpret_cast<IpcCApiProxyTest *>(userData);
if (proxyTest != nullptr) {
proxyTest->ClearResource();
}
OH_LOG_INFO(LOG_APP, "the stub is dead!");
}
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3.4 服务端调用入口,服务端文件"libipcCapiDemo.so"
c++
IpcCApiStubTest g_ipcStubObj;
#ifdef __cplusplus
extern "C" {
// 服务需要实现如下函数,具体可参考元能力接口说明
OHIPCRemoteStub* NativeChildProcess_OnConnect() {
OH_LOG_INFO(LOG_APP, "NativeChildProcess_OnConnect");
return g_ipcStubObj.GetRemoteStub();
}
void NativeChildProcess_MainProc() {
OH_LOG_INFO(LOG_APP, "NativeChildProcess_MainProc");
g_ipcStubObj.MainProc();
OH_LOG_INFO(LOG_APP, "NativeChildProcess_MainProc End");
}
}
#endif
3.5 客户端调用入口
cpp
IpcCApiProxyTest *g_ipcProxy = nullptr;
// 元能力打通IPC通道回调接口
void OnNativeChildProcessStarted(int errCode, OHIPCRemoteProxy *remoteProxy) {
OH_LOG_INFO(LOG_APP, "OnNativeChildProcessStarted proxy=%{public}p err=%{public}d", remoteProxy, errCode);
if (remoteProxy == nullptr) {
return;
}
g_ipcProxy = new (std::nothrow) IpcCApiProxyTest(remoteProxy);
if (g_ipcProxy == nullptr) {
OH_IPCRemoteProxy_Destroy(remoteProxy);
OH_LOG_ERROR(LOG_APP, "Alloc IpcCApiProxyTest object failed");
return;
}
}
int main(int argc, char *argv[]) {
int32_t ret = OH_Ability_CreateNativeChildProcess("libipcCapiDemo.so", OnNativeChildProcessStarted);
if (ret != 0) {
return -1;
}
if (g_ipcProxy == nullptr) {
return -1;
}
int a = 2;
int b = 3;
int result = 0;
ret = g_ipcProxy->AsyncAdd(a, b, result);
OH_LOG_INFO(LOG_APP, "AsyncAdd: %d + %d = %d, ret=%d", a, b, result, ret);
//kill stub端
ret = g_ipcProxy->RequestExitChildProcess();
//控制台输出: the stub is dead!
if (g_ipcProxy != nullptr) {
delete g_ipcProxy;
g_ipcProxy = nullptr;
}
return 0;
}