kc3-lang/SDL/src/thread/stdcpp/SDL_systhread.cpp

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• Hash : 46bb47cf
  Author :
  Date : 2020-03-26T22:14:59
  

  thread: Put all important SDL_CreateThread internal data into SDL_Thread. This avoids the need to malloc something extra, use a semaphore, etc, and fixes Emscripten with pthreads support, which might not spin up a web worker until after SDL_CreateThread returns and thus can't wait on a semaphore at this point in any case. Fixes Bugzilla #5064.

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• src/thread/stdcpp/SDL_systhread.cpp

• /*
    Simple DirectMedia Layer
    Copyright (C) 1997-2020 Sam Lantinga <slouken@libsdl.org>
  
    This software is provided 'as-is', without any express or implied
    warranty.  In no event will the authors be held liable for any damages
    arising from the use of this software.
  
    Permission is granted to anyone to use this software for any purpose,
    including commercial applications, and to alter it and redistribute it
    freely, subject to the following restrictions:
  
    1. The origin of this software must not be misrepresented; you must not
       claim that you wrote the original software. If you use this software
       in a product, an acknowledgment in the product documentation would be
       appreciated but is not required.
    2. Altered source versions must be plainly marked as such, and must not be
       misrepresented as being the original software.
    3. This notice may not be removed or altered from any source distribution.
  */
  #include "../../SDL_internal.h"
  
  /* Thread management routines for SDL */
  
  extern "C" {
  #include "SDL_thread.h"
  #include "../SDL_thread_c.h"
  #include "../SDL_systhread.h"
  #include "SDL_log.h"
  }
  
  #include <mutex>
  #include <thread>
  #include <system_error>
  
  #ifdef __WINRT__
  #include <Windows.h>
  #endif
  
  static void
  RunThread(void *args)
  {
      SDL_RunThread((SDL_Thread *) args);
  }
  
  extern "C"
  int
  SDL_SYS_CreateThread(SDL_Thread * thread)
  {
      try {
          // !!! FIXME: no way to set a thread stack size here.
          std::thread cpp_thread(RunThread, thread);
          thread->handle = (void *) new std::thread(std::move(cpp_thread));
          return 0;
      } catch (std::system_error & ex) {
          SDL_SetError("unable to start a C++ thread: code=%d; %s", ex.code(), ex.what());
          return -1;
      } catch (std::bad_alloc &) {
          SDL_OutOfMemory();
          return -1;
      }
  }
  
  extern "C"
  void
  SDL_SYS_SetupThread(const char *name)
  {
      // Make sure a thread ID gets assigned ASAP, for debugging purposes:
      SDL_ThreadID();
      return;
  }
  
  extern "C"
  SDL_threadID
  SDL_ThreadID(void)
  {
  #ifdef __WINRT__
      return GetCurrentThreadId();
  #else
      // HACK: Mimick a thread ID, if one isn't otherwise available.
      static thread_local SDL_threadID current_thread_id = 0;
      static SDL_threadID next_thread_id = 1;
      static std::mutex next_thread_id_mutex;
  
      if (current_thread_id == 0) {
          std::lock_guard<std::mutex> lock(next_thread_id_mutex);
          current_thread_id = next_thread_id;
          ++next_thread_id;
      }
  
      return current_thread_id;
  #endif
  }
  
  extern "C"
  int
  SDL_SYS_SetThreadPriority(SDL_ThreadPriority priority)
  {
  #ifdef __WINRT__
      int value;
  
      if (priority == SDL_THREAD_PRIORITY_LOW) {
          value = THREAD_PRIORITY_LOWEST;
      }
      else if (priority == SDL_THREAD_PRIORITY_HIGH) {
          value = THREAD_PRIORITY_HIGHEST;
      }
      else if (priority == SDL_THREAD_PRIORITY_TIME_CRITICAL) {
          // FIXME: WinRT does not support TIME_CRITICAL! -flibit
          SDL_LogWarn(SDL_LOG_CATEGORY_SYSTEM, "TIME_CRITICAL unsupported, falling back to HIGHEST");
          value = THREAD_PRIORITY_HIGHEST;
      }
      else {
          value = THREAD_PRIORITY_NORMAL;
      }
      if (!SetThreadPriority(GetCurrentThread(), value)) {
          return WIN_SetError("SetThreadPriority()");
      }
      return 0;
  #else
      return SDL_Unsupported();
  #endif
  }
  
  extern "C"
  void
  SDL_SYS_WaitThread(SDL_Thread * thread)
  {
      if ( ! thread) {
          return;
      }
  
      try {
          std::thread * cpp_thread = (std::thread *) thread->handle;
          if (cpp_thread->joinable()) {
              cpp_thread->join();
          }
      } catch (std::system_error &) {
          // An error occurred when joining the thread.  SDL_WaitThread does not,
          // however, seem to provide a means to report errors to its callers
          // though!
      }
  }
  
  extern "C"
  void
  SDL_SYS_DetachThread(SDL_Thread * thread)
  {
      if ( ! thread) {
          return;
      }
  
      try {
          std::thread * cpp_thread = (std::thread *) thread->handle;
          if (cpp_thread->joinable()) {
              cpp_thread->detach();
          }
      } catch (std::system_error &) {
          // An error occurred when detaching the thread.  SDL_DetachThread does not,
          // however, seem to provide a means to report errors to its callers
          // though!
      }
  }
  
  extern "C"
  SDL_TLSData *
  SDL_SYS_GetTLSData(void)
  {
      return SDL_Generic_GetTLSData();
  }
  
  extern "C"
  int
  SDL_SYS_SetTLSData(SDL_TLSData *data)
  {
      return SDL_Generic_SetTLSData(data);
  }
  
  /* vi: set ts=4 sw=4 expandtab: */
  

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