跨平台开发有许多问题要解决，为了方便，通常需要将不同平台的相同功能做封装，以期提供统一的接口供上层调用，这种平台差异的封装意味着更多的代码和更不友好的维护性。线程就是如此，而C++11在语言层面上对线程提供了支持，今天就把之前的线程实现改成了C++11的方式，代码大大简化。
之前的Windows平台线程封装：
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| class Thread {
DISALLOW_COPY_AND_ASSIGN(Thread)
public:
Thread();
virtual ~Thread();
public:
void Run();
void Wait();
int GetThreadId() const {
return static_cast<int>(m_threadId);
}
int SetThreadId(int threadId) {
m_threadId = static_cast<DWORD>(threadId);
}
protected:
virtual void Execute() = 0;
private:
static unsigned int __stdcall ThreadFunc(void* arg);
private:
HANDLE m_hThread;
DWORD m_threadId;
};
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| Thread::Thread()
: m_hThread(0)
, m_threadId(0) {}
Thread::~Thread() {
if (0 != m_threadId) {
Wait();
}
}
void Thread::Run() {
unsigned int threadId = 0;
uintptr_t ret = ::_beginthreadex(nullptr
, 0
, ThreadFunc
, this
, 0
, &threadId);
m_hThread = reinterpret_cast<HANDLE>(ret);
m_threadId = threadId;
}
void Thread::Wait() {
if (0 != m_threadId) {
::WaitForSingleObject(m_hThread, INFINITE);
::CloseHandle(m_hThread);
m_threadId = 0;
}
}
unsigned int __stdcall Thread::ThreadFunc(void* arg) {
Thread* thread = static_cast<Thread*>(arg);
thread->Execute();
return 0;
}
|
之前的Linux平台线程封装：
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| class Thread {
DISALLOW_COPY_AND_ASSIGN(Thread)
public:
Thread();
virtual ~Thread();
public:
void Run();
void Wait();
int GetThreadId() const {
return static_cast<int>(m_threadId);
}
void SetThreadId(int threadId) {
m_threadId = static_cast<pthread_t>(threadId);
}
protected:
virtual void Execute() = 0;
private:
static void* ThreadFunc(void* arg);
private:
pthread_t m_threadId;
};
|
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| Thread::Thread()
: m_threadId(0) {}
Thread::~Thread() {
if (0 != m_threadId) {
Wait();
}
}
void Thread::Run() {
const int ret = ::pthread_create(&m_threadId
, nullptr
, ThreadFunc
, this);
ASSERT_TRUE(0 == ret);
}
void Thread::Wait() {
if (0 != m_threadId) {
void* status = nullptr;
const int ret = ::pthread_join(m_threadId, &status);
ASSERT_TRUE(0 == ret);
m_threadId = 0;
}
}
void* Thread::ThreadFunc(void* arg) {
Thread* thread = static_cast<Thread*>(arg);
thread->Execute();
return nullptr;
}
|
C++11版的线程实现：
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| class Thread {
DISALLOW_COPY_AND_ASSIGN(Thread)
public:
Thread();
virtual ~Thread();
public:
void Run();
void Wait();
void Detach();
std::thread::id GetThreadId() const;
protected:
virtual void Execute() = 0;
private:
void ThreadFunc();
private:
std::thread m_thread;
};
inline std::thread::id Thread::GetThreadId() const {
return m_thread.get_id();
}
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| Thread::Thread() {}
Thread::~Thread() {}
void Thread::Run() {
m_thread = std::thread(std::bind(Thread::ThreadFunc, this));
}
void Thread::Wait() {
if (m_thread.joinable()) {
m_thread.join();
}
}
void Thread::Detach() {
m_thread.detach();
}
void Thread::ThreadFunc() {
Execute();
}
|