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+/***************************************************************************
+ * Copyright (C) 2006-2007 by Rajko Albrecht *
+ * *
+ * This program is free software; you can redistribute it and/or modify *
+ * it under the terms of the GNU General Public License as published by *
+ * the Free Software Foundation; either version 2 of the License, or *
+ * (at your option) any later version. *
+ * *
+ * This program is distributed in the hope that it will be useful, *
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
+ * GNU General Public License for more details. *
+ * *
+ * You should have received a copy of the GNU General Public License *
+ * along with this program; if not, write to the *
+ * Free Software Foundation, Inc., *
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. *
+ ***************************************************************************/
+#ifndef _smart_pointer_hpp
+#define _smart_pointer_hpp
+
+#if defined QT_THREAD_SUPPORT
+#include "qmutex.h"
+#endif
+
+#include "svnqt/svnqt_defines.hpp"
+
+/*!
+ * \file smart_pointer.h
+ * \brief smart pointer and reference counter
+ * \author Rajko Albrecht
+ *
+ */
+
+namespace svn
+{
+
+//! simple reference counter class
+class ref_count {
+protected:
+ //! reference count member
+ long m_RefCount;
+#ifdef QT_THREAD_SUPPORT
+ QMutex m_RefcountMutex;
+#endif
+public:
+ //! first reference must be added after "new" via Pointer()
+ ref_count() : m_RefCount(0)
+#ifdef QT_THREAD_SUPPORT
+ ,m_RefcountMutex()
+#endif
+ {}
+ virtual ~ref_count() {}
+ //! add a reference
+ void Incr() {
+#ifdef QT_THREAD_SUPPORT
+ QMutexLocker a(&m_RefcountMutex);
+#endif
+ ++m_RefCount;
+ }
+ //! delete a reference
+ bool Decr() {
+#ifdef QT_THREAD_SUPPORT
+ QMutexLocker a(&m_RefcountMutex);
+#endif
+ --m_RefCount;
+ return Shared();
+ }
+ //! is it referenced
+ bool Shared() { return (m_RefCount > 0); }
+};
+
+//! reference counting wrapper class
+template<class T> class smart_pointer {
+ //! pointer to object
+ /*!
+ * this object must contain Incr(), Decr() and Shared()
+ * methode as public members. The best way is, that it will be a child
+ * class of RefCount
+ */
+ T *ptr;
+public:
+ //! standart constructor
+ smart_pointer() { ptr = 0; }
+ //! standart destructor
+ /*!
+ * release the reference, if it were the last reference, destroys
+ * ptr
+ */
+ ~smart_pointer()
+ {
+ if (ptr && !ptr->Decr()) {
+ delete ptr;
+ }
+ }
+ //! construction
+ smart_pointer(T* t) { if ( (ptr = t) ) ptr->Incr(); }
+ //! Pointer copy
+ smart_pointer(const smart_pointer<T>& p)
+ { if ( (ptr = p.ptr) ) ptr->Incr(); }
+ //! pointer copy by assignment
+ smart_pointer<T>& operator= (const smart_pointer<T>& p)
+ {
+ // already same: nothing to do
+ if (ptr == p.ptr) return *this;
+ // decouple reference
+ if ( ptr && !ptr->Decr()) delete ptr;
+ // establish new reference
+ if ( (ptr = p.ptr) ) ptr->Incr();
+ return *this;
+ }
+ smart_pointer<T>& operator= (T*p)
+ {
+ if (ptr==p)return *this;
+ if (ptr && !ptr->Decr()) delete ptr;
+ if ( (ptr=p) ) ptr->Incr();
+ return *this;
+ }
+
+ //! cast to conventional pointer
+ operator T* () const { return ptr; }
+
+ //! deref: fails for 0 pointer
+ T& operator* () {return *ptr; }
+ //! deref: fails for 0 pointer
+ const T& operator* ()const {return *ptr; }
+
+ //! deref with method call
+ T* operator-> () {return ptr; }
+ //! deref with const method call
+ const T* operator-> ()const {return ptr; }
+
+ //! supports "if (pointer)"
+ operator bool () const { return (ptr != 0); }
+ //! "if (pointer)" as non const
+ operator bool () { return ptr != 0;}
+
+ //! support if (!pointer)"
+ bool operator! () const { return (ptr == 0); }
+ //! support if (!pointer)" as non const
+ bool operator! () { return (ptr == 0); }
+};
+
+} // namespace svn
+#endif