threads in MinGW

mingw.thread.h

@@ -0,0 +1,360 @@
+/**
+* @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;
+            int errnum = errno;
+            delete call;
+//  Note: Should only throw EINVAL, EAGAIN, EACCES
+            throw std::system_error(errnum, std::generic_category());
+        } 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()))
+            throw system_error(make_error_code(errc::resource_deadlock_would_occur));
+        if (mHandle == kInvalidHandle)
+            throw system_error(make_error_code(errc::no_such_process));
+        if (!joinable())
+            throw system_error(make_error_code(errc::invalid_argument));
+        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;
+            throw system_error(make_error_code(errc::invalid_argument));
+        }
+        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)
+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