kc3-lang/angle/src/tests/test_utils/MultiThreadSteps.h

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• Author : Tim Van Patten
  Date : 2021-08-20 18:34:10
  Hash : 460618ad
  Message : Refactor EGLMultiThreadSteps.h -> MultiThreadSteps.h The class ThreadSynchronization is very useful when synchronizing multiple threads in ANGLE tests, so it's being moved from egl_tests/EGLMultiThreadSteps.h to test_utils/MultiThreadSteps.h. Bug: angleproject:5971 Change-Id: I5df469aa68b79cf72d95e0276f42ab33a091314e Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3111887 Reviewed-by: Ian Elliott <ianelliott@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Tim Van Patten <timvp@google.com>

• src/tests/test_utils/MultiThreadSteps.h

• //
  // Copyright 2021 The ANGLE Project Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  //
  // EGLMultiContextTest.cpp:
  //   Synchronization help for tests that use multiple threads.
  
  #include <atomic>
  #include <condition_variable>
  #include <mutex>
  #include <thread>
  
  namespace
  {
  
  // The following class is used by tests that need multiple threads that coordinate their actions
  // via an enum of "steps".  This enum is the template type E.  The enum must have at least the
  // following values:
  //
  // - Finish   This value indicates that one thread has finished its last step and is cleaning up.
  //            The other thread waits for this before it does its last step and cleans up.
  // - Abort    This value indicates that one thread encountered a GL error and has exited.  This
  //            will cause the other thread (that is waiting for a different step) to also abort.
  //
  // This class is RAII.  It is declared at the top of a thread, and will be deconstructed at the end
  // of the thread's outer block.  If the thread encounters a GL error, the deconstructor will abort
  // the other thread using the E:Abort step.
  template <typename E>
  class ThreadSynchronization
  {
    public:
      ThreadSynchronization(E *currentStep, std::mutex *mutex, std::condition_variable *condVar)
          : mCurrentStep(currentStep), mMutex(mutex), mCondVar(condVar)
      {}
      ~ThreadSynchronization()
      {
          bool isAborting = false;
          {
              // If the other thread isn't finished, cause it to abort.
              std::unique_lock<std::mutex> lock(*mMutex);
              isAborting = *mCurrentStep != E::Finish;
  
              if (isAborting)
              {
                  *mCurrentStep = E::Abort;
              }
          }
          mCondVar->notify_all();
      }
  
      // Helper functions to synchronize the threads so that the operations are executed in the
      // specific order the test is written for.
      bool waitForStep(E waitStep)
      {
          std::unique_lock<std::mutex> lock(*mMutex);
          while (*mCurrentStep != waitStep)
          {
              // If necessary, abort execution as the other thread has encountered a GL error.
              if (*mCurrentStep == E::Abort)
              {
                  return false;
              }
              mCondVar->wait(lock);
          }
  
          return true;
      }
  
      void nextStep(E newStep)
      {
          {
              std::unique_lock<std::mutex> lock(*mMutex);
              *mCurrentStep = newStep;
          }
          mCondVar->notify_one();
      }
  
    private:
      E *mCurrentStep;
      std::mutex *mMutex;
      std::condition_variable *mCondVar;
  };
  }  // anonymous namespace