QtCollider/safeptr.hpp

   1 /************************************************************************
   2 *
   3 * Copyright 2011 Jakob Leben (jakob.leben@gmail.com)
   4 *
   5 * This file is part of SuperCollider Qt GUI.
   6 *
   7 * This program is free software: you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License as published by
   9 * the Free Software Foundation, either version 3 of the License, or
  10 * (at your option) any later version.
  11 *
  12 * This program is distributed in the hope that it will be useful,
  13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 * GNU General Public License for more details.
  16 *
  17 * You should have received a copy of the GNU General Public License
  18 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 *
  20 ************************************************************************/
  21
  22 #ifndef QC_SAFE_PTR_H
  23 #define QC_SAFE_PTR_H
  24
  25 #include "Common.h"
  26
  27 #include <QApplication>
  28 #include <QAtomicPointer>
  29 #include <QAtomicInt>
  30 #include <QMutex>
  31
  32 namespace QtCollider {
  33
  34 template<typename T> class SafePtr
  35 {
  36 public:
  37   SafePtr() : d(0) {}
  38
  39   SafePtr( const SafePtr & other )
  40   : d ( other.d )
  41   {
  42     ref();
  43   }
  44
  45   SafePtr( T* ptr )
  46   : d ( new Data( ptr ) )
  47   {}
  48
  49   SafePtr & operator= ( const SafePtr & other ) {
  50     deref();
  51     d = other.d;
  52     ref();
  53     return *this;
  54   }
  55
  56   ~SafePtr() {
  57     deref();
  58   }
  59
  60   T * operator-> () const { return d->ptr; }
  61
  62   T & operator* () const { return *d->ptr; }
  63
  64   operator T* () const { return (d ? d->ptr : 0); }
  65
  66   T *ptr() const { return (d ? d->ptr : 0); }
  67
  68   void *id() const { return (void*) d; } // useful for checking internal pointer identity
  69
  70   void invalidate() { qcDebugMsg(2,"SafePtr: invalidating"); if(d) d->ptr = 0; }
  71
  72 private:
  73   struct Data {
  74     Data ( T * ptr_ ) : ptr(ptr_), refCount(1) {}
  75     QAtomicPointer<T> ptr;
  76     QAtomicInt refCount;
  77   };
  78
  79   void ref() {
  80     if( d ) {
  81       d->refCount.ref();
  82       qcDebugMsg(2,QString("SafePtr: +refcount = %1").arg(d->refCount));
  83     }
  84   }
  85   void deref() {
  86     if( d ) {
  87       bool ref = d->refCount.deref();
  88       qcDebugMsg(2,QString("SafePtr: -refcount = %1").arg(d->refCount));
  89       if( !ref ) {
  90         qcDebugMsg(2,"SafePtr: unreferenced!");
  91         delete d;
  92       }
  93     }
  94   }
  95
  96   Data *d;
  97 };
  98
  99 } // namespace QtCollider
 100
 101 #endif