comparison DEPENDENCIES/generic/include/boost/interprocess/sync/scoped_lock.hpp @ 16:2665513ce2d3

Add boost headers

+//////////////////////////////////////////////////////////////////////////////
+//
+// (C) Copyright Ion Gaztanaga 2005-2012. Distributed under the Boost
+// Software License, Version 1.0. (See accompanying file
+// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// See http://www.boost.org/libs/interprocess for documentation.
+//
+//////////////////////////////////////////////////////////////////////////////
+//
+// This interface is inspired by Howard Hinnant's lock proposal.
+// http://home.twcny.rr.com/hinnant/cpp_extensions/threads_move.html
+//
+//////////////////////////////////////////////////////////////////////////////
+
+#ifndef BOOST_INTERPROCESS_SCOPED_LOCK_HPP
+#define BOOST_INTERPROCESS_SCOPED_LOCK_HPP
+
+#if (defined _MSC_VER) && (_MSC_VER >= 1200)
+#  pragma once
+#endif
+
+#include <boost/interprocess/detail/config_begin.hpp>
+#include <boost/interprocess/detail/workaround.hpp>
+#include <boost/interprocess/interprocess_fwd.hpp>
+#include <boost/interprocess/sync/lock_options.hpp>
+#include <boost/interprocess/exceptions.hpp>
+#include <boost/interprocess/detail/mpl.hpp>
+#include <boost/interprocess/detail/type_traits.hpp>
+#include <boost/move/move.hpp>
+#include <boost/interprocess/detail/posix_time_types_wrk.hpp>
+
+//!\file
+//!Describes the scoped_lock class.
+
+namespace boost {
+namespace interprocess {
+
+
+//!scoped_lock is meant to carry out the tasks for locking, unlocking, try-locking
+//!and timed-locking (recursive or not) for the Mutex. The Mutex need not supply all
+//!of this functionality. If the client of scoped_lock<Mutex> does not use
+//!functionality which the Mutex does not supply, no harm is done. Mutex ownership
+//!transfer is supported through the syntax of move semantics. Ownership transfer
+//!is allowed both by construction and assignment. The scoped_lock does not support
+//!copy semantics. A compile time error results if copy construction or copy
+//!assignment is attempted. Mutex ownership can also be moved from an
+//!upgradable_lock and sharable_lock via constructor. In this role, scoped_lock
+//!shares the same functionality as a write_lock.
+template <class Mutex>
+class scoped_lock
+{
+   /// @cond
+   private:
+   typedef scoped_lock<Mutex> this_type;
+   BOOST_MOVABLE_BUT_NOT_COPYABLE(scoped_lock)
+   typedef bool this_type::*unspecified_bool_type;
+   /// @endcond
+   public:
+
+   typedef Mutex mutex_type;
+
+   //!Effects: Default constructs a scoped_lock.
+   //!Postconditions: owns() == false and mutex() == 0.
+   scoped_lock()
+      : mp_mutex(0), m_locked(false)
+   {}
+
+   //!Effects: m.lock().
+   //!Postconditions: owns() == true and mutex() == &m.
+   //!Notes: The constructor will take ownership of the mutex. If another thread
+   //!   already owns the mutex, this thread will block until the mutex is released.
+   //!   Whether or not this constructor handles recursive locking depends upon the mutex.
+   explicit scoped_lock(mutex_type& m)
+      : mp_mutex(&m), m_locked(false)
+   {  mp_mutex->lock();   m_locked = true;  }
+
+   //!Postconditions: owns() == false, and mutex() == &m.
+   //!Notes: The constructor will not take ownership of the mutex. There is no effect
+   //!   required on the referenced mutex.
+   scoped_lock(mutex_type& m, defer_lock_type)
+      : mp_mutex(&m), m_locked(false)
+   {}
+
+   //!Postconditions: owns() == true, and mutex() == &m.
+   //!Notes: The constructor will suppose that the mutex is already locked. There
+   //!   is no effect required on the referenced mutex.
+   scoped_lock(mutex_type& m, accept_ownership_type)
+      : mp_mutex(&m), m_locked(true)
+   {}
+
+   //!Effects: m.try_lock().
+   //!Postconditions: mutex() == &m. owns() == the return value of the
+   //!   m.try_lock() executed within the constructor.
+   //!Notes: The constructor will take ownership of the mutex if it can do
+   //!   so without waiting. Whether or not this constructor handles recursive
+   //!   locking depends upon the mutex. If the mutex_type does not support try_lock,
+   //!   this constructor will fail at compile time if instantiated, but otherwise
+   //!   have no effect.
+   scoped_lock(mutex_type& m, try_to_lock_type)
+      : mp_mutex(&m), m_locked(mp_mutex->try_lock())
+   {}
+
+   //!Effects: m.timed_lock(abs_time).
+   //!Postconditions: mutex() == &m. owns() == the return value of the
+   //!   m.timed_lock(abs_time) executed within the constructor.
+   //!Notes: The constructor will take ownership of the mutex if it can do
+   //!   it until abs_time is reached. Whether or not this constructor
+   //!   handles recursive locking depends upon the mutex. If the mutex_type
+   //!   does not support try_lock, this constructor will fail at compile
+   //!   time if instantiated, but otherwise have no effect.
+   scoped_lock(mutex_type& m, const boost::posix_time::ptime& abs_time)
+      : mp_mutex(&m), m_locked(mp_mutex->timed_lock(abs_time))
+   {}
+
+   //!Postconditions: mutex() == the value scop.mutex() had before the
+   //!   constructor executes. s1.mutex() == 0. owns() == the value of
+   //!   scop.owns() before the constructor executes. scop.owns().
+   //!Notes: If the scop scoped_lock owns the mutex, ownership is moved
+   //!   to thisscoped_lock with no blocking. If the scop scoped_lock does not
+   //!   own the mutex, then neither will this scoped_lock. Only a moved
+   //!   scoped_lock's will match this signature. An non-moved scoped_lock
+   //!   can be moved with the expression: "boost::move(lock);". This
+   //!   constructor does not alter the state of the mutex, only potentially
+   //!   who owns it.
+   scoped_lock(BOOST_RV_REF(scoped_lock) scop)
+      : mp_mutex(0), m_locked(scop.owns())
+   {  mp_mutex = scop.release(); }
+
+   //!Effects: If upgr.owns() then calls unlock_upgradable_and_lock() on the
+   //!   referenced mutex. upgr.release() is called.
+   //!Postconditions: mutex() == the value upgr.mutex() had before the construction.
+   //!   upgr.mutex() == 0. owns() == upgr.owns() before the construction.
+   //!   upgr.owns() == false after the construction.
+   //!Notes: If upgr is locked, this constructor will lock this scoped_lock while
+   //!   unlocking upgr. If upgr is unlocked, then this scoped_lock will be
+   //!   unlocked as well. Only a moved upgradable_lock's will match this
+   //!   signature. An non-moved upgradable_lock can be moved with
+   //!   the expression: "boost::move(lock);" This constructor may block if
+   //!   other threads hold a sharable_lock on this mutex (sharable_lock's can
+   //!   share ownership with an upgradable_lock).
+   template<class T>
+   explicit scoped_lock(BOOST_RV_REF(upgradable_lock<T>) upgr
+      , typename ipcdetail::enable_if< ipcdetail::is_same<T, Mutex> >::type * = 0)
+      : mp_mutex(0), m_locked(false)
+   {
+      upgradable_lock<mutex_type> &u_lock = upgr;
+      if(u_lock.owns()){
+         u_lock.mutex()->unlock_upgradable_and_lock();
+         m_locked = true;
+      }
+      mp_mutex = u_lock.release();
+   }
+
+   //!Effects: If upgr.owns() then calls try_unlock_upgradable_and_lock() on the
+   //!referenced mutex:
+   //!   a)if try_unlock_upgradable_and_lock() returns true then mutex() obtains
+   //!      the value from upgr.release() and owns() is set to true.
+   //!   b)if try_unlock_upgradable_and_lock() returns false then upgr is
+   //!      unaffected and this scoped_lock construction as the same effects as
+   //!      a default construction.
+   //!   c)Else upgr.owns() is false. mutex() obtains the value from upgr.release()
+   //!      and owns() is set to false
+   //!Notes: This construction will not block. It will try to obtain mutex
+   //!   ownership from upgr immediately, while changing the lock type from a
+   //!   "read lock" to a "write lock". If the "read lock" isn't held in the
+   //!   first place, the mutex merely changes type to an unlocked "write lock".
+   //!   If the "read lock" is held, then mutex transfer occurs only if it can
+   //!   do so in a non-blocking manner.
+   template<class T>
+   scoped_lock(BOOST_RV_REF(upgradable_lock<T>) upgr, try_to_lock_type
+         , typename ipcdetail::enable_if< ipcdetail::is_same<T, Mutex> >::type * = 0)
+      : mp_mutex(0), m_locked(false)
+   {
+      upgradable_lock<mutex_type> &u_lock = upgr;
+      if(u_lock.owns()){
+         if((m_locked = u_lock.mutex()->try_unlock_upgradable_and_lock()) == true){
+            mp_mutex = u_lock.release();
+         }
+      }
+      else{
+         u_lock.release();
+      }
+   }
+
+   //!Effects: If upgr.owns() then calls timed_unlock_upgradable_and_lock(abs_time)
+   //!   on the referenced mutex:
+   //!   a)if timed_unlock_upgradable_and_lock(abs_time) returns true then mutex()
+   //!      obtains the value from upgr.release() and owns() is set to true.
+   //!   b)if timed_unlock_upgradable_and_lock(abs_time) returns false then upgr
+   //!      is unaffected and this scoped_lock construction as the same effects
+   //!      as a default construction.
+   //!   c)Else upgr.owns() is false. mutex() obtains the value from upgr.release()
+   //!      and owns() is set to false
+   //!Notes: This construction will not block. It will try to obtain mutex ownership
+   //!   from upgr immediately, while changing the lock type from a "read lock" to a
+   //!   "write lock". If the "read lock" isn't held in the first place, the mutex
+   //!   merely changes type to an unlocked "write lock". If the "read lock" is held,
+   //!   then mutex transfer occurs only if it can do so in a non-blocking manner.
+   template<class T>
+   scoped_lock(BOOST_RV_REF(upgradable_lock<T>) upgr, boost::posix_time::ptime &abs_time
+               , typename ipcdetail::enable_if< ipcdetail::is_same<T, Mutex> >::type * = 0)
+      : mp_mutex(0), m_locked(false)
+   {
+      upgradable_lock<mutex_type> &u_lock = upgr;
+      if(u_lock.owns()){
+         if((m_locked = u_lock.mutex()->timed_unlock_upgradable_and_lock(abs_time)) == true){
+            mp_mutex = u_lock.release();
+         }
+      }
+      else{
+         u_lock.release();
+      }
+   }
+
+   //!Effects: If shar.owns() then calls try_unlock_sharable_and_lock() on the
+   //!referenced mutex.
+   //!   a)if try_unlock_sharable_and_lock() returns true then mutex() obtains
+   //!      the value from shar.release() and owns() is set to true.
+   //!   b)if try_unlock_sharable_and_lock() returns false then shar is
+   //!      unaffected and this scoped_lock construction has the same
+   //!      effects as a default construction.
+   //!   c)Else shar.owns() is false. mutex() obtains the value from
+   //!      shar.release() and owns() is set to false
+   //!Notes: This construction will not block. It will try to obtain mutex
+   //!   ownership from shar immediately, while changing the lock type from a
+   //!   "read lock" to a "write lock". If the "read lock" isn't held in the
+   //!   first place, the mutex merely changes type to an unlocked "write lock".
+   //!   If the "read lock" is held, then mutex transfer occurs only if it can
+   //!   do so in a non-blocking manner.
+   template<class T>
+   scoped_lock(BOOST_RV_REF(sharable_lock<T>) shar, try_to_lock_type
+      , typename ipcdetail::enable_if< ipcdetail::is_same<T, Mutex> >::type * = 0)
+      : mp_mutex(0), m_locked(false)
+   {
+      sharable_lock<mutex_type> &s_lock = shar;
+      if(s_lock.owns()){
+         if((m_locked = s_lock.mutex()->try_unlock_sharable_and_lock()) == true){
+            mp_mutex = s_lock.release();
+         }
+      }
+      else{
+         s_lock.release();
+      }
+   }
+
+   //!Effects: if (owns()) mp_mutex->unlock().
+   //!Notes: The destructor behavior ensures that the mutex lock is not leaked.*/
+   ~scoped_lock()
+   {
+      try{  if(m_locked && mp_mutex)   mp_mutex->unlock();  }
+      catch(...){}
+   }
+
+   //!Effects: If owns() before the call, then unlock() is called on mutex().
+   //!   *this gets the state of scop and scop gets set to a default constructed state.
+   //!Notes: With a recursive mutex it is possible that both this and scop own
+   //!   the same mutex before the assignment. In this case, this will own the
+   //!   mutex after the assignment (and scop will not), but the mutex's lock
+   //!   count will be decremented by one.
+   scoped_lock &operator=(BOOST_RV_REF(scoped_lock) scop)
+   {
+      if(this->owns())
+         this->unlock();
+      m_locked = scop.owns();
+      mp_mutex = scop.release();
+      return *this;
+   }
+
+   //!Effects: If mutex() == 0 or if already locked, throws a lock_exception()
+   //!   exception. Calls lock() on the referenced mutex.
+   //!Postconditions: owns() == true.
+   //!Notes: The scoped_lock changes from a state of not owning the mutex, to
+   //!   owning the mutex, blocking if necessary.
+   void lock()
+   {
+      if(!mp_mutex || m_locked)
+         throw lock_exception();
+      mp_mutex->lock();
+      m_locked = true;
+   }
+
+   //!Effects: If mutex() == 0 or if already locked, throws a lock_exception()
+   //!   exception. Calls try_lock() on the referenced mutex.
+   //!Postconditions: owns() == the value returned from mutex()->try_lock().
+   //!Notes: The scoped_lock changes from a state of not owning the mutex, to
+   //!   owning the mutex, but only if blocking was not required. If the
+   //!   mutex_type does not support try_lock(), this function will fail at
+   //!   compile time if instantiated, but otherwise have no effect.*/
+   bool try_lock()
+   {
+      if(!mp_mutex || m_locked)
+         throw lock_exception();
+      m_locked = mp_mutex->try_lock();
+      return m_locked;
+   }
+
+   //!Effects: If mutex() == 0 or if already locked, throws a lock_exception()
+   //!   exception. Calls timed_lock(abs_time) on the referenced mutex.
+   //!Postconditions: owns() == the value returned from mutex()-> timed_lock(abs_time).
+   //!Notes: The scoped_lock changes from a state of not owning the mutex, to
+   //!   owning the mutex, but only if it can obtain ownership by the specified
+   //!   time. If the mutex_type does not support timed_lock (), this function
+   //!   will fail at compile time if instantiated, but otherwise have no effect.*/
+   bool timed_lock(const boost::posix_time::ptime& abs_time)
+   {
+      if(!mp_mutex || m_locked)
+         throw lock_exception();
+      m_locked = mp_mutex->timed_lock(abs_time);
+      return m_locked;
+   }
+
+   //!Effects: If mutex() == 0 or if not locked, throws a lock_exception()
+   //!   exception. Calls unlock() on the referenced mutex.
+   //!Postconditions: owns() == false.
+   //!Notes: The scoped_lock changes from a state of owning the mutex, to not
+   //!   owning the mutex.*/
+   void unlock()
+   {
+      if(!mp_mutex || !m_locked)
+         throw lock_exception();
+      mp_mutex->unlock();
+      m_locked = false;
+   }
+
+   //!Effects: Returns true if this scoped_lock has acquired
+   //!the referenced mutex.
+   bool owns() const
+   {  return m_locked && mp_mutex;  }
+
+   //!Conversion to bool.
+   //!Returns owns().
+   operator unspecified_bool_type() const
+   {  return m_locked? &this_type::m_locked : 0;   }
+
+   //!Effects: Returns a pointer to the referenced mutex, or 0 if
+   //!there is no mutex to reference.
+   mutex_type* mutex() const
+   {  return  mp_mutex;  }
+
+   //!Effects: Returns a pointer to the referenced mutex, or 0 if there is no
+   //!   mutex to reference.
+   //!Postconditions: mutex() == 0 and owns() == false.
+   mutex_type* release()
+   {
+      mutex_type *mut = mp_mutex;
+      mp_mutex = 0;
+      m_locked = false;
+      return mut;
+   }
+
+   //!Effects: Swaps state with moved lock.
+   //!Throws: Nothing.
+   void swap( scoped_lock<mutex_type> &other)
+   {
+      std::swap(mp_mutex, other.mp_mutex);
+      std::swap(m_locked, other.m_locked);
+   }
+
+   /// @cond
+   private:
+   mutex_type *mp_mutex;
+   bool        m_locked;
+   /// @endcond
+};
+
+} // namespace interprocess
+} // namespace boost
+
+#include <boost/interprocess/detail/config_end.hpp>
+
+#endif // BOOST_INTERPROCESS_SCOPED_LOCK_HPP