text: /*
      This file is a part of libcds - Concurrent Data Structures library
  
      (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2017
  
      Source code repo: http://github.com/khizmax/libcds/
      Download: http://sourceforge.net/projects/libcds/files/
  
      Redistribution and use in source and binary forms, with or without
      modification, are permitted provided that the following conditions are met:
  
      * Redistributions of source code must retain the above copyright notice, this
      list of conditions and the following disclaimer.
  
      * Redistributions in binary form must reproduce the above copyright notice,
      this list of conditions and the following disclaimer in the documentation
      and/or other materials provided with the distribution.
  
      THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
      AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
      IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
      DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
      FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
      DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
      SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
      CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
      OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
      OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
  
  #ifndef CDSTEST_THREAD_H
  #define CDSTEST_THREAD_H
  
  #include <cds_test/ext_gtest.h>
  #include <vector>
  #include <thread>
  #include <condition_variable>
  #include <mutex>
  #include <chrono>
  #include <cds/threading/model.h>
  
  namespace cds_test {
  
      // Forwards
      class thread;
      class thread_pool;
  
      // Test thread
      class thread
      {
          void run();
  
      protected: // thread_pool interface
          thread( thread const& sample );
  
          virtual ~thread()
          {}
  
      protected:
          virtual thread * clone() = 0;
          virtual void test() = 0;
  
          virtual void SetUp()
          {
              cds::threading::Manager::attachThread();
          }
  
          virtual void TearDown()
          {
              cds::threading::Manager::detachThread();
          }
  
      public:
          explicit thread( thread_pool& master, int type = 0 );
  
          thread_pool& pool() { return m_pool; }
          int type() const { return m_type; }
          size_t id() const { return m_id;  }
          bool time_elapsed() const;
  
      private:
          friend class thread_pool;
  
          thread_pool&    m_pool;
          int const       m_type;
          size_t const    m_id;
      };
  
      // Pool of test threads
      class thread_pool
      {
          class barrier
          {
          public:
              barrier()
                  : m_count( 0 )
              {}
  
              void reset( size_t count )
              {
                  std::unique_lock< std::mutex > lock( m_mtx );
                  m_count = count;
              }
  
              bool wait()
              {
                  std::unique_lock< std::mutex > lock( m_mtx );
                  if ( --m_count == 0 ) {
                      m_cv.notify_all();
                      return true;
                  }
  
                  while ( m_count != 0 )
                      m_cv.wait( lock );
  
                  return false;
              }
  
          private:
              size_t      m_count;
              std::mutex  m_mtx;
              std::condition_variable m_cv;
          };
  
          class initial_gate
          {
          public:
              initial_gate()
                  : m_ready( false )
              {}
  
              void wait()
              {
                  std::unique_lock< std::mutex > lock( m_mtx );
                  while ( !m_ready )
                      m_cv.wait( lock );
              }
  
              void ready()
              {
                  std::unique_lock< std::mutex > lock( m_mtx );
                  m_ready = true;
                  m_cv.notify_all();
              }
  
              void reset()
              {
                  std::unique_lock< std::mutex > lock( m_mtx );
                  m_ready = false;
              }
  
          private:
              std::mutex  m_mtx;
              std::condition_variable m_cv;
              bool        m_ready;
          };
  
      public:
          explicit thread_pool( ::testing::Test& fixture )
              : m_fixture( fixture )
              , m_bTimeElapsed( false )
          {}
  
          ~thread_pool()
          {
              clear();
          }
  
          void add( thread * what )
          {
              m_workers.push_back( what );
          }
  
          void add( thread * what, size_t count )
          {
              add( what );
              for ( size_t i = 1; i < count; ++i ) {
                  thread * p = what->clone();
                  add( p );
              }
          }
  
          std::chrono::milliseconds run()
          {
              return run( std::chrono::seconds::zero());
          }
  
          std::chrono::milliseconds run( std::chrono::seconds duration )
          {
              m_startBarrier.reset( m_workers.size() + 1 );
              m_stopBarrier.reset( m_workers.size() + 1 );
  
              // Create threads
              std::vector< std::thread > threads;
              threads.reserve( m_workers.size());
              for ( auto w : m_workers )
                  threads.emplace_back( &thread::run, w );
  
              // The pool is intialized
              m_startPoint.ready();
  
              m_bTimeElapsed.store( false, std::memory_order_release );
  
              auto native_duration = std::chrono::duration_cast<std::chrono::steady_clock::duration>(duration);
  
              // The pool is ready to start all workers
              m_startBarrier.wait();
  
              auto time_start = std::chrono::steady_clock::now();
              auto const expected_end = time_start + native_duration;
  
              if ( duration != std::chrono::seconds::zero()) {
                  for ( ;; ) {
                      std::this_thread::sleep_for( native_duration );
                      auto time_now = std::chrono::steady_clock::now();
                      if ( time_now >= expected_end )
                          break;
                      native_duration = expected_end - time_now;
                  }
              }
              m_bTimeElapsed.store( true, std::memory_order_release );
  
              // Waiting for all workers done
              m_stopBarrier.wait();
  
              auto time_end = std::chrono::steady_clock::now();
  
              for ( auto& t : threads )
                  t.join();
  
              return m_testDuration = std::chrono::duration_cast<std::chrono::milliseconds>(time_end - time_start);
          }
  
          size_t size() const             { return m_workers.size(); }
          thread& get( size_t idx ) const { return *m_workers.at( idx ); }
  
          template <typename Fixture>
          Fixture& fixture()
          {
              return static_cast<Fixture&>(m_fixture);
          }
  
          std::chrono::milliseconds duration() const { return m_testDuration; }
  
          void clear()
          {
              for ( auto t : m_workers )
                  delete t;
              m_workers.clear();
              m_startPoint.reset();
          }
  
          void reset()
          {
              clear();
          }
  
      protected: // thread interface
          size_t get_next_id()
          {
              return m_workers.size();
          }
  
          void ready_to_start( thread& /*who*/ )
          {
              // Called from test thread
  
              // Wait until the pool is ready
              m_startPoint.wait();
  
              // Wait until all thread ready
              m_startBarrier.wait();
          }
  
          void thread_done( thread& /*who*/ )
          {
              // Called from test thread
              m_stopBarrier.wait();
          }
  
      private:
          friend class thread;
  
          ::testing::Test&        m_fixture;
          std::vector<thread *>   m_workers;
  
          initial_gate            m_startPoint;
          barrier                 m_startBarrier;
          barrier                 m_stopBarrier;
  
          std::atomic<bool> m_bTimeElapsed;
          std::chrono::milliseconds m_testDuration;
      };
  
      inline thread::thread( thread_pool& master, int type /*= 0*/ )
          : m_pool( master )
          , m_type( type )
          , m_id( master.get_next_id())
      {}
  
      inline thread::thread( thread const& sample )
          : m_pool( sample.m_pool )
          , m_type( sample.m_type )
          , m_id( m_pool.get_next_id())
      {}
  
      inline void thread::run()
      {
          SetUp();
          m_pool.ready_to_start( *this );
          test();
          m_pool.thread_done( *this );
          TearDown();
      }
  
      inline bool thread::time_elapsed() const
      {
          return m_pool.m_bTimeElapsed.load( std::memory_order_acquire );
      }
  
  } // namespace cds_test
  
  #endif // CDSTEST_THREAD_H
  