AutoViewLock.h

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//     ____   ______ __
//    / __ \ / ____// /
//   / /_/ // /    / /
//  / ____// /___ / /___   PixInsight Class Library
// /_/     \____//_____/   PCL 2.7.0
// ----------------------------------------------------------------------------
// pcl/AutoViewLock.h - Released 2024-06-18T15:48:54Z
// ----------------------------------------------------------------------------
// This file is part of the PixInsight Class Library (PCL).
// PCL is a multiplatform C++ framework for development of PixInsight modules.
//
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//
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// ----------------------------------------------------------------------------
 
#ifndef __PCL_AutoViewLock_h
#define __PCL_AutoViewLock_h
 
 
#include <pcl/Defs.h>
#include <pcl/Diagnostics.h>
 
#include <pcl/Atomic.h>
#include <pcl/View.h>
 
namespace pcl
{
 
// ----------------------------------------------------------------------------
 
class PCL_CLASS AutoViewLock
{
public:
 
   explicit AutoViewLock( View& view, bool lock = true )
      : m_view( view )
      , m_readLock( 0 )
      , m_writeLock( 0 )
   {
      if ( lock )
         Lock();
   }
 
   ~AutoViewLock()
   {
      Unlock();
      m_view = View::Null();
   }
 
   AutoViewLock( const AutoViewLock& ) = delete;
 
   AutoViewLock& operator =( const AutoViewLock& ) = delete;
 
   void Lock()
   {
      if ( !m_view.IsNull() )
      {
         int unlocked = 0;
         if ( m_readLock.TestAndSet( 0, 1 ) )
            ++unlocked;
         if ( m_writeLock.TestAndSet( 0, 1 ) )
            ++unlocked;
         if ( unlocked )
            m_view.Lock();
      }
   }
 
   void Unlock()
   {
      if ( !m_view.IsNull() )
      {
         int locked = 0;
         if ( m_readLock.TestAndSet( 1, 0 ) )
            ++locked;
         if ( m_writeLock.TestAndSet( 1, 0 ) )
            ++locked;
         if ( locked )
            m_view.Unlock();
      }
   }
 
   void LockForWrite()
   {
      if ( !m_view.IsNull() )
         if ( m_writeLock.TestAndSet( 0, 1 ) )
            m_view.LockForWrite();
   }
 
   void UnlockForRead()
   {
      if ( !m_view.IsNull() )
         if ( m_readLock.TestAndSet( 1, 0 ) )
            m_view.UnlockForRead();
   }
 
   void RelockForRead()
   {
      if ( !m_view.IsNull() )
         if ( m_readLock.TestAndSet( 0, 1 ) )
            m_view.RelockForRead();
   }
 
private:
 
   View      m_view;
   AtomicInt m_readLock;
   AtomicInt m_writeLock;
};
 
class PCL_CLASS AutoViewWriteLock : public AutoViewLock
{
public:
 
   explicit AutoViewWriteLock( View& view )
      : AutoViewLock( view, false/*lock*/ )
   {
      LockForWrite();
   }
};
 
// ----------------------------------------------------------------------------
 
} // pcl
 
#endif   // __PCL_AutoViewLock_h
 
// ----------------------------------------------------------------------------
// EOF pcl/AutoViewLock.h - Released 2024-06-18T15:48:54Z