/**
* @file mingw.thread.h
* @brief std::thread implementation for MinGW
* (c) 2013-2016 by Mega Limited, Auckland, New Zealand
* @author Alexander Vassilev
*
* @copyright Simplified (2-clause) BSD License.
* You should have received a copy of the license along with this
* program.
*
* This code is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* @note
* This file may become part of the mingw-w64 runtime package. If/when this happens,
* the appropriate license will be added, i.e. this code will become dual-licensed,
* and the current BSD 2-clause license will stay.
*/
#ifndef WIN32STDTHREAD_H
#define WIN32STDTHREAD_H
#if !defined(__cplusplus) || (__cplusplus < 201103L)
#error A C++11 compiler is required!
#endif
// Use the standard classes for std::, if available.
#include <thread>
#include <cstddef> // For std::size_t
#include <cerrno> // Detect error type.
#include <exception> // For std::terminate
#include <system_error> // For std::system_error
#include <functional> // For std::hash
#include <tuple> // For std::tuple
#include <chrono> // For sleep timing.
#include <memory> // For std::unique_ptr
#include <iosfwd> // Stream output for thread ids.
#include <utility> // For std::swap, std::forward
#include "mingw.invoke.h"
#if (defined(__MINGW32__) && !defined(__MINGW64_VERSION_MAJOR))
#pragma message "The Windows API that MinGW-w32 provides is not fully compatible\
with Microsoft's API. We'll try to work around this, but we can make no\
guarantees. This problem does not exist in MinGW-w64."
#include <windows.h> // No further granularity can be expected.
#else
#include <synchapi.h> // For WaitForSingleObject
#include <handleapi.h> // For CloseHandle, etc.
#include <sysinfoapi.h> // For GetNativeSystemInfo
#include <processthreadsapi.h> // For GetCurrentThreadId
#endif
#include <process.h> // For _beginthreadex
#ifndef NDEBUG
#include <cstdio>
#endif
#if !defined(_WIN32_WINNT) || (_WIN32_WINNT < 0x0501)
#error To use the MinGW-std-threads library, you will need to define the macro _WIN32_WINNT to be 0x0501 (Windows XP) or higher.
#endif
// Instead of INVALID_HANDLE_VALUE, _beginthreadex returns 0.
namespace mingw_stdthread
{
namespace detail
{
template<std::size_t...>
struct IntSeq {};
template<std::size_t N, std::size_t... S>
struct GenIntSeq : GenIntSeq<N-1, N-1, S...> { };
template<std::size_t... S>
struct GenIntSeq<0, S...> { typedef IntSeq<S...> type; };
// Use a template specialization to avoid relying on compiler optimization
// when determining the parameter integer sequence.
template<class Func, class T, typename... Args>
class ThreadFuncCall;
// We can't define the Call struct in the function - the standard forbids template methods in that case
template<class Func, std::size_t... S, typename... Args>
class ThreadFuncCall<Func, detail::IntSeq<S...>, Args...>
{
static_assert(sizeof...(S) == sizeof...(Args), "Args must match.");
using Tuple = std::tuple<typename std::decay<Args>::type...>;
typename std::decay<Func>::type mFunc;
Tuple mArgs;
public:
ThreadFuncCall(Func&& aFunc, Args&&... aArgs)
: mFunc(std::forward<Func>(aFunc)),
mArgs(std::forward<Args>(aArgs)...)
{
}
void callFunc()
{
detail::invoke(std::move(mFunc), std::move(std::get<S>(mArgs)) ...);
}
};
// Allow construction of threads without exposing implementation.
class ThreadIdTool;
} // Namespace "detail"
class thread
{
public:
class id
{
DWORD mId = 0;
friend class thread;
friend class std::hash<id>;
friend class detail::ThreadIdTool;
explicit id(DWORD aId) noexcept : mId(aId){}
public:
id (void) noexcept = default;
friend bool operator==(id x, id y) noexcept {return x.mId == y.mId; }
friend bool operator!=(id x, id y) noexcept {return x.mId != y.mId; }
friend bool operator< (id x, id y) noexcept {return x.mId < y.mId; }
friend bool operator<=(id x, id y) noexcept {return x.mId <= y.mId; }
friend bool operator> (id x, id y) noexcept {return x.mId > y.mId; }
friend bool operator>=(id x, id y) noexcept {return x.mId >= y.mId; }
template<class _CharT, class _Traits>
friend std::basic_ostream<_CharT, _Traits>&
operator<<(std::basic_ostream<_CharT, _Traits>& __out, id __id)
{
if (__id.mId == 0)
{
return __out << "(invalid std::thread::id)";
}
else
{
return __out << __id.mId;
}
}
};
private:
static constexpr HANDLE kInvalidHandle = nullptr;
static constexpr DWORD kInfinite = 0xffffffffl;
HANDLE mHandle;
id mThreadId;
template <class Call>
static unsigned __stdcall threadfunc(void* arg)
{
std::unique_ptr<Call> call(static_cast<Call*>(arg));
call->callFunc();
return 0;
}
static unsigned int _hardware_concurrency_helper() noexcept
{
SYSTEM_INFO sysinfo;
// This is one of the few functions used by the library which has a nearly-
// equivalent function defined in earlier versions of Windows. Include the
// workaround, just as a reminder that it does exist.
#if defined(_WIN32_WINNT) && (_WIN32_WINNT >= 0x0501)
::GetNativeSystemInfo(&sysinfo);
#else
::GetSystemInfo(&sysinfo);
#endif
return sysinfo.dwNumberOfProcessors;
}
public:
typedef HANDLE native_handle_type;
id get_id() const noexcept {return mThreadId;}
native_handle_type native_handle() const {return mHandle;}
thread(): mHandle(kInvalidHandle), mThreadId(){}
thread(thread&& other)
:mHandle(other.mHandle), mThreadId(other.mThreadId)
{
other.mHandle = kInvalidHandle;
other.mThreadId = id{};
}
thread(const thread &other)=delete;
template<class Func, typename... Args>
explicit thread(Func&& func, Args&&... args) : mHandle(), mThreadId()
{
using ArgSequence = typename detail::GenIntSeq<sizeof...(Args)>::type;
using Call = detail::ThreadFuncCall<Func, ArgSequence, Args...>;
auto call = new Call(
std::forward<Func>(func), std::forward<Args>(args)...);
unsigned id_receiver;
auto int_handle = _beginthreadex(NULL, 0, threadfunc<Call>,
static_cast<LPVOID>(call), 0, &id_receiver);
if (int_handle == 0)
{
mHandle = kInvalidHandle;
delete call;
// Note: Should only throw EINVAL, EAGAIN, EACCES
__builtin_trap();
} else {
mThreadId.mId = id_receiver;
mHandle = reinterpret_cast<HANDLE>(int_handle);
}
}
bool joinable() const {return mHandle != kInvalidHandle;}
// Note: Due to lack of synchronization, this function has a race condition
// if called concurrently, which leads to undefined behavior. The same applies
// to all other member functions of this class, but this one is mentioned
// explicitly.
void join()
{
using namespace std;
if (get_id() == id(GetCurrentThreadId()))
__builtin_trap();
if (mHandle == kInvalidHandle)
__builtin_trap();
if (!joinable())
__builtin_trap();
WaitForSingleObject(mHandle, kInfinite);
CloseHandle(mHandle);
mHandle = kInvalidHandle;
mThreadId = id{};
}
~thread()
{
if (joinable())
{
#ifndef NDEBUG
std::printf("Error: Must join() or detach() a thread before \
destroying it.\n");
#endif
std::terminate();
}
}
thread& operator=(const thread&) = delete;
thread& operator=(thread&& other) noexcept
{
if (joinable())
{
#ifndef NDEBUG
std::printf("Error: Must join() or detach() a thread before \
moving another thread to it.\n");
#endif
std::terminate();
}
swap(std::forward<thread>(other));
return *this;
}
void swap(thread&& other) noexcept
{
std::swap(mHandle, other.mHandle);
std::swap(mThreadId.mId, other.mThreadId.mId);
}
static unsigned int hardware_concurrency() noexcept
{
static unsigned int cached = _hardware_concurrency_helper();
return cached;
}
void detach()
{
if (!joinable())
{
using namespace std;
__builtin_trap();
}
if (mHandle != kInvalidHandle)
{
CloseHandle(mHandle);
mHandle = kInvalidHandle;
}
mThreadId = id{};
}
};
namespace detail
{
class ThreadIdTool
{
public:
static thread::id make_id (DWORD base_id) noexcept
{
return thread::id(base_id);
}
};
} // Namespace "detail"
namespace this_thread
{
inline thread::id get_id() noexcept
{
return detail::ThreadIdTool::make_id(GetCurrentThreadId());
}
inline void yield() noexcept {Sleep(0);}
template< class Rep, class Period >
void sleep_for( const std::chrono::duration<Rep,Period>& sleep_duration)
{
static constexpr DWORD kInfinite = 0xffffffffl;
using namespace std::chrono;
using rep = milliseconds::rep;
rep ms = duration_cast<milliseconds>(sleep_duration).count();
while (ms > 0)
{
constexpr rep kMaxRep = static_cast<rep>(kInfinite - 1);
auto sleepTime = (ms < kMaxRep) ? ms : kMaxRep;
Sleep(static_cast<DWORD>(sleepTime));
ms -= sleepTime;
}
}
template <class Clock, class Duration>
void sleep_until(const std::chrono::time_point<Clock,Duration>& sleep_time)
{
sleep_for(sleep_time-Clock::now());
}
}
} // Namespace mingw_stdthread
namespace std
{
// Because of quirks of the compiler, the common "using namespace std;"
// directive would flatten the namespaces and introduce ambiguity where there
// was none. Direct specification (std::), however, would be unaffected.
// Take the safe option, and include only in the presence of MinGW's win32
// implementation.
#if defined(__MINGW32__ ) && !defined(_GLIBCXX_HAS_GTHREADS) && !defined(__clang__)
using mingw_stdthread::thread;
// Remove ambiguity immediately, to avoid problems arising from the above.
//using std::thread;
namespace this_thread
{
using namespace mingw_stdthread::this_thread;
}
#elif !defined(MINGW_STDTHREAD_REDUNDANCY_WARNING) // Skip repetition
#define MINGW_STDTHREAD_REDUNDANCY_WARNING
#pragma message "This version of MinGW seems to include a win32 port of\
pthreads, and probably already has C++11 std threading classes implemented,\
based on pthreads. These classes, found in namespace std, are not overridden\
by the mingw-std-thread library. If you would still like to use this\
implementation (as it is more lightweight), use the classes provided in\
namespace mingw_stdthread."
#endif
// Specialize hash for this implementation's thread::id, even if the
// std::thread::id already has a hash.
template<>
struct hash<mingw_stdthread::thread::id>
{
typedef mingw_stdthread::thread::id argument_type;
typedef size_t result_type;
size_t operator() (const argument_type & i) const noexcept
{
return i.mId;
}
};
}
#endif // WIN32STDTHREAD_H
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