TMCAutoLock.h

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// -----------------------------------------------------------------------
// Copyright (C) 2019 CERN and copyright holders of VMC Project.
// This software is distributed under the terms of the GNU General Public
// License v3 (GPL Version 3), copied verbatim in the file "LICENSE".
//
// See https://github.com/vmc-project/vmc for full licensing information.
// -----------------------------------------------------------------------
 
// Author: Ivana Hrivnacova, 24/03/2017
 
/*************************************************************************
 * Copyright (C) 2014, Rene Brun and Fons Rademakers.                    *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/
 
#ifndef TMCAUTOLOCK_HH
#define TMCAUTOLOCK_HH
 
//------------------------------------------------
// The Geant4 Virtual Monte Carlo package
// Copyright (C) 2013, 2014 Ivana Hrivnacova
// All rights reserved.
//
// For the licensing terms see geant4_vmc/LICENSE.
// Contact: root-vmc@cern.ch
//-------------------------------------------------
 
 
// clang-format off
 
//
// ********************************************************************
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// * the Geant4 Collaboration.  It is provided  under  the terms  and *
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// ********************************************************************
//
// G4Autolock
//
// Class Description:
//
// This class provides a mechanism to create a mutex and locks/unlocks it.
// Can be used by applications to implement in a portable way a mutexing logic.
// Usage Example:
//
//      #include "G4Threading.hh"
//      #include "G4AutoLock.hh"
//
//      // defined somewhere -- static so all threads see the same mutex
//      static G4Mutex aMutex;
//
//      // somewhere else:
//      // The G4AutoLock instance will automatically unlock the mutex when it
//      // goes out of scope. One typically defines the scope within { } if
//      // there is thread-safe code following the auto-lock
//
//      {
//          G4AutoLock l(&aMutex);
//          ProtectedCode();
//      }
//
//      UnprotectedCode();
//
//      // When ProtectedCode() is calling a function that also tries to lock
//      // a normal G4AutoLock + G4Mutex will "deadlock". In other words, the
//      // the mutex in the ProtectedCode() function will wait forever to
//      // acquire the lock that is being held by the function that called
//      // ProtectedCode(). In this situation, use a G4RecursiveAutoLock +
//      // G4RecursiveMutex, e.g.
//
//      // defined somewhere -- static so all threads see the same mutex
//      static G4RecursiveMutex aRecursiveMutex;
//
//      // this function is sometimes called directly and sometimes called
//      // from SomeFunction_B(), which also locks the mutex
//      void SomeFunction_A()
//      {
//          // when called from SomeFunction_B(), a G4Mutex + G4AutoLock will
//          // deadlock
//          G4RecursiveAutoLock l(&aRecursiveMutex);
//          // do something
//      }
//
//      void SomeFunction_B()
//      {
//
//          {
//              G4RecursiveAutoLock l(&aRecursiveMutex);
//              SomeFunction_A();
//          }
//
//          UnprotectedCode();
//      }
//
 
// --------------------------------------------------------------------
// Author: Andrea Dotti (15 Feb 2013): First Implementation
//
// Update: Jonathan Madsen (9 Feb 2018): Replaced custom implementation
//      with inheritance from C++11 unique_lock, which inherits the
//      following member functions:
//
//      - unique_lock(unique_lock&& other) noexcept;
//      - explicit unique_lock(mutex_type& m);
//      - unique_lock(mutex_type& m, std::defer_lock_t t) noexcept;
//      - unique_lock(mutex_type& m, std::try_to_lock_t t);
//      - unique_lock(mutex_type& m, std::adopt_lock_t t);
//
//      - template <typename Rep, typename Period>
//        unique_lock(mutex_type& m,
//                   const std::chrono::duration<Rep,Period>& timeout_duration);
//
//      - template<typename Clock, typename Duration>
//        unique_lock(mutex_type& m,
//              const std::chrono::time_point<Clock,Duration>& timeout_time);
//
//      - void lock();
//      - void unlock();
//      - bool try_lock();
//
//      - template <typename Rep, typename Period>
//        bool try_lock_for(const std::chrono::duration<Rep,Period>&);
//
//      - template <typename Rep, typename Period>
//        bool try_lock_until(const std::chrono::time_point<Clock,Duration>&);
//
//      - void swap(unique_lock& other) noexcept;
//      - mutex_type* release() noexcept;
//      - mutex_type* mutex() const noexcept;
//      - bool owns_lock() const noexcept;
//      - explicit operator bool() const noexcept;
//      - unique_lock& operator=(unique_lock&& other);
//
// --------------------------------------------------------------------
//
// Note that G4AutoLock is defined also for a sequential Geant4 build but below
// regarding implementation (also found in G4Threading.hh)
//
//
//          NOTE ON GEANT4 SERIAL BUILDS AND MUTEX/UNIQUE_LOCK
//          ==================================================
//
// G4Mutex and G4RecursiveMutex are always C++11 std::mutex types
// however, in serial mode, using G4MUTEXLOCK and G4MUTEXUNLOCK on these
// types has no effect -- i.e. the mutexes are not actually locked or unlocked
//
// Additionally, when a G4Mutex or G4RecursiveMutex is used with G4AutoLock
// and G4RecursiveAutoLock, respectively, these classes also suppressing
// the locking and unlocking of the mutex. Regardless of the build type,
// G4AutoLock and G4RecursiveAutoLock inherit from std::unique_lock<std::mutex>
// and std::unique_lock<std::recursive_mutex>, respectively. This means
// that in situations (such as is needed by the analysis category), the
// G4AutoLock and G4RecursiveAutoLock can be passed to functions requesting
// a std::unique_lock. Within these functions, since std::unique_lock
// member functions are not virtual, they will not retain the dummy locking
// and unlocking behavior
// --> An example of this behavior can be found below
//
//  Jonathan R. Madsen (February 21, 2018)
//
// --------------------------------------------------------------------
 
#ifndef _WIN32
#define TMCMULTITHREADED 1
#endif
 
#include <chrono>
#include <iostream>
#include <mutex>
#include <system_error>
 
 
// Definitions from G4Threading.hh
 
// Global mutex types
using TMCMutex          = std::mutex;
using TMCRecursiveMutex = std::recursive_mutex;
using thread_lock =
  int (*)(TMCMutex*);  // typedef Int (*thread_lock)(TMCMutex*);
using thread_unlock =
  int (*)(TMCMutex*);  // typedef int (*thread_unlock)(TMCMutex*);
 
 
// Mutex macros
#define TMCMUTEX_INITIALIZER                                               \
  {}
 
#if defined(TMCMULTITHREADED)
// mutex macros
#define TMCMUTEXLOCK(mutex)                                                \
{                                                                          \
  (mutex)->lock();                                                         \
}
#define TMCMUTEXUNLOCK(mutex)                                              \
{                                                                          \
  (mutex)->unlock();                                                       \
}
#else
// mutex macros
#define TMCMUTEXLOCK(mutex)                                                \
  {}
#define TMCMUTEXUNLOCK(mutex)                                              \
  {}
#endif
 
// Note: Note that TMCTemplateAutoLock by itself is not thread-safe and
//       cannot be shared among threads due to the locked switch
//
template <typename _Mutex_t>
class TMCTemplateAutoLock : public std::unique_lock<_Mutex_t>
{
 public:
  //------------------------------------------------------------------------//
  // Some useful typedefs
  //------------------------------------------------------------------------//
  typedef std::unique_lock<_Mutex_t> unique_lock_t;
  typedef TMCTemplateAutoLock<_Mutex_t> this_type;
  typedef typename unique_lock_t::mutex_type mutex_type;
 
 public:
  //------------------------------------------------------------------------//
  // STL-consistent reference form constructors
  //------------------------------------------------------------------------//
 
  // reference form is consistent with STL lock_guard types
  // Locks the associated mutex by calling m.lock(). The behavior is
  // undefined if the current thread already owns the mutex except when
  // the mutex is recursive
  TMCTemplateAutoLock(mutex_type& _mutex)
    : unique_lock_t(_mutex, std::defer_lock)
  {
    // call termination-safe locking. if serial, this call has no effect
    _lock_deferred();
  }
 
  // Tries to lock the associated mutex by calling
  // m.try_lock_for(_timeout_duration). Blocks until specified
  // _timeout_duration has elapsed or the lock is acquired, whichever comes
  // first. May block for longer than _timeout_duration.
  template <typename Rep, typename Period>
  TMCTemplateAutoLock(
    mutex_type& _mutex,
    const std::chrono::duration<Rep, Period>& _timeout_duration)
    : unique_lock_t(_mutex, std::defer_lock)
  {
    // call termination-safe locking. if serial, this call has no effect
    _lock_deferred(_timeout_duration);
  }
 
  // Tries to lock the associated mutex by calling
  // m.try_lock_until(_timeout_time). Blocks until specified _timeout_time has
  // been reached or the lock is acquired, whichever comes first. May block
  // for longer than until _timeout_time has been reached.
  template <typename Clock, typename Duration>
  TMCTemplateAutoLock(
    mutex_type& _mutex,
    const std::chrono::time_point<Clock, Duration>& _timeout_time)
    : unique_lock_t(_mutex, std::defer_lock)
  {
    // call termination-safe locking. if serial, this call has no effect
    _lock_deferred(_timeout_time);
  }
 
  // Does not lock the associated mutex.
  TMCTemplateAutoLock(mutex_type& _mutex, std::defer_lock_t _lock) noexcept
    : unique_lock_t(_mutex, _lock)
  {}
 
#ifdef TMCMULTITHREADED
 
  // Tries to lock the associated mutex without blocking by calling
  // m.try_lock(). The behavior is undefined if the current thread already
  // owns the mutex except when the mutex is recursive.
  TMCTemplateAutoLock(mutex_type& _mutex, std::try_to_lock_t _lock)
    : unique_lock_t(_mutex, _lock)
  {}
 
  // Assumes the calling thread already owns m
  TMCTemplateAutoLock(mutex_type& _mutex, std::adopt_lock_t _lock)
    : unique_lock_t(_mutex, _lock)
  {}
 
#else
 
  // serial dummy version (initializes unique_lock but does not lock)
  TMCTemplateAutoLock(mutex_type& _mutex, std::try_to_lock_t)
    : unique_lock_t(_mutex, std::defer_lock)
  {}
 
  // serial dummy version (initializes unique_lock but does not lock)
  TMCTemplateAutoLock(mutex_type& _mutex, std::adopt_lock_t)
    : unique_lock_t(_mutex, std::defer_lock)
  {}
 
#endif  // defined(TMCMULTITHREADED)
 
 public:
  //------------------------------------------------------------------------//
  // Backwards compatibility versions (constructor with pointer to mutex)
  //------------------------------------------------------------------------//
  TMCTemplateAutoLock(mutex_type* _mutex)
    : unique_lock_t(*_mutex, std::defer_lock)
  {
    // call termination-safe locking. if serial, this call has no effect
    _lock_deferred();
  }
 
  TMCTemplateAutoLock(mutex_type* _mutex, std::defer_lock_t _lock) noexcept
    : unique_lock_t(*_mutex, _lock)
  {}
 
#if defined(TMCMULTITHREADED)
 
  TMCTemplateAutoLock(mutex_type* _mutex, std::try_to_lock_t _lock)
    : unique_lock_t(*_mutex, _lock)
  {}
 
  TMCTemplateAutoLock(mutex_type* _mutex, std::adopt_lock_t _lock)
    : unique_lock_t(*_mutex, _lock)
  {}
 
#else  // NOT defined(TMCMULTITHREADED) -- i.e. serial
 
  TMCTemplateAutoLock(mutex_type* _mutex, std::try_to_lock_t)
    : unique_lock_t(*_mutex, std::defer_lock)
  {}
 
  TMCTemplateAutoLock(mutex_type* _mutex, std::adopt_lock_t)
    : unique_lock_t(*_mutex, std::defer_lock)
  {}
 
#endif  // defined(TMCMULTITHREADED)
 
 public:
  //------------------------------------------------------------------------//
  // Non-constructor overloads
  //------------------------------------------------------------------------//
 
#if defined(TMCMULTITHREADED)
 
  // overload nothing
 
#else  // NOT defined(TMCMULTITHREADED) -- i.e. serial
 
  // override unique lock member functions to keep from locking/unlocking
  // but does not override in polymorphic usage
  void lock() {}
  void unlock() {}
  bool try_lock() { return true; }
 
  template <typename Rep, typename Period>
  bool try_lock_for(const std::chrono::duration<Rep, Period>&)
  {
    return true;
  }
 
  template <typename Clock, typename Duration>
  bool try_lock_until(const std::chrono::time_point<Clock, Duration>&)
  {
    return true;
  }
 
  void swap(this_type& other) noexcept { std::swap(*this, other); }
  bool owns_lock() const noexcept { return false; }
 
  // no need to overload
  // explicit operator bool() const noexcept;
  // this_type& operator=(this_type&& other);
  // mutex_type* release() noexcept;
  // mutex_type* mutex() const noexcept;
 
#endif  // defined(TMCMULTITHREADED)
 
 private:
// helpful macros
#define _is_stand_mutex(_Tp) (std::is_same<_Tp, TMCMutex>::value)
#define _is_recur_mutex(_Tp) (std::is_same<_Tp, TMCRecursiveMutex>::value)
#define _is_other_mutex(_Tp) (!_is_stand_mutex(_Tp) && !_is_recur_mutex(_Tp))
 
  template <typename _Tp                                             = _Mutex_t,
            typename std::enable_if<_is_stand_mutex(_Tp), int>::type = 0>
  std::string GetTypeString()
  {
    return "TMCAutoLock<TMCMutex>";
  }
 
  template <typename _Tp                                             = _Mutex_t,
            typename std::enable_if<_is_recur_mutex(_Tp), int>::type = 0>
  std::string GetTypeString()
  {
    return "TMCAutoLock<TMCRecursiveMutex>";
  }
 
  template <typename _Tp                                             = _Mutex_t,
            typename std::enable_if<_is_other_mutex(_Tp), int>::type = 0>
  std::string GetTypeString()
  {
    return "TMCAutoLock<UNKNOWN_MUTEX>";
  }
 
// pollution is bad
#undef _is_stand_mutex
#undef _is_recur_mutex
#undef _is_other_mutex
 
  // used in _lock_deferred chrono variants to avoid ununsed-variable warning
  template <typename _Tp>
  void suppress_unused_variable(const _Tp&)
  {}
 
  //========================================================================//
  // NOTE on _lock_deferred(...) variants:
  //      a system_error in lock means that the mutex is unavailable
  //      we want to throw the error that comes from locking an unavailable
  //      mutex so that we know there is a memory leak
  //      if the mutex is valid, this will hold until the other thread
  //      finishes
 
  // sometimes certain destructors use locks, this isn't an issue unless
  // the object is leaked. When this occurs, the application finalization
  // (i.e. the real or implied "return 0" part of main) will call destructors
  // on Geant4 object after some static mutex variables are deleted, leading
  // to the error code (typically on Clang compilers):
  //      libc++abi.dylib: terminating with uncaught exception of type
  //      std::__1::system_error: mutex lock failed: Invalid argument
  // this function protects against this failure until such a time that
  // these issues have been resolved
 
  //========================================================================//
  // standard locking
  inline void _lock_deferred()
  {
#if defined(TMCMULTITHREADED)
    try
    {
      this->unique_lock_t::lock();
    } catch(std::system_error& e)
    {
      PrintLockErrorMessage(e);
    }
#endif
  }
 
  //========================================================================//
  // Tries to lock the associated mutex by calling
  // m.try_lock_for(_timeout_duration). Blocks until specified
  // _timeout_duration has elapsed or the lock is acquired, whichever comes
  // first. May block for longer than _timeout_duration.
  template <typename Rep, typename Period>
  void _lock_deferred(
    const std::chrono::duration<Rep, Period>& _timeout_duration)
  {
#if defined(TMCMULTITHREADED)
    try
    {
      this->unique_lock_t::try_lock_for(_timeout_duration);
    } catch(std::system_error& e)
    {
      PrintLockErrorMessage(e);
    }
#else
    suppress_unused_variable(_timeout_duration);
#endif
  }
 
  //========================================================================//
  // Tries to lock the associated mutex by calling
  // m.try_lock_until(_timeout_time). Blocks until specified _timeout_time has
  // been reached or the lock is acquired, whichever comes first. May block
  // for longer than until _timeout_time has been reached.
  template <typename Clock, typename Duration>
  void _lock_deferred(
    const std::chrono::time_point<Clock, Duration>& _timeout_time)
  {
#if defined(TMCMULTITHREADED)
    try
    {
      this->unique_lock_t::try_lock_until(_timeout_time);
    } catch(std::system_error& e)
    {
      PrintLockErrorMessage(e);
    }
#else
    suppress_unused_variable(_timeout_time);
#endif
  }
 
  //========================================================================//
  // the message for what mutex lock fails due to deleted static mutex
  // at termination
  void PrintLockErrorMessage(std::system_error& e)
  {
    // use std::cout/std::endl to avoid include dependencies
    using std::cout;
    using std::endl;
    // the error that comes from locking an unavailable mutex
    cout << "Non-critical error: mutex lock failure in "
         << GetTypeString<mutex_type>() << ". "
         << "If the app is terminating, Geant4 failed to "
         << "delete an allocated resource and a Geant4 destructor is "
         << "being called after the statics were destroyed. \n\t--> "
         << "Exception: [code: " << e.code() << "] caught: " << e.what()
         << endl;
    // suppress_unused_variable(e);
  }
};
 
// -------------------------------------------------------------------------- //
//
//      Use the non-template types below:
//          - TMCAutoLock with TMCMutex
//          - TMCRecursiveAutoLock with TMCRecursiveMutex
//
// -------------------------------------------------------------------------- //
 
using TMCAutoLock          = TMCTemplateAutoLock<TMCMutex>;
using TMCRecursiveAutoLock = TMCTemplateAutoLock<TMCRecursiveMutex>;
 
// provide abbriviated type if another mutex type is desired to be used
// aside from above
template <typename _Tp>
using TMCTAutoLock = TMCTemplateAutoLock<_Tp>;
 
 
 
#endif // TMCAUTOLOCK_HH