From ee50361d9f4d657f4867491403a058d0a85c36a4 Mon Sep 17 00:00:00 2001
From: Martin Nolte <mnolte@dune-project.org>
Date: Wed, 22 Aug 2012 08:14:23 +0000
Subject: [PATCH] add SmartPtr
SmartPtr< T > is similar to shared_ptr< T > in its intention. However, it
demands methods addReference and removeReference on the object it points to.
Actually, you could implement shared_ptr< T > through a
SmartPtr< RefCountWrapper< T > > and a few cast operators.
[[Imported from SVN: r6919]]
---
dune/common/Makefile.am | 1 +
dune/common/smartptr.hh | 107 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 108 insertions(+)
create mode 100644 dune/common/smartptr.hh
diff --git a/dune/common/Makefile.am b/dune/common/Makefile.am
index 19262854a..b3f283bba 100644
--- a/dune/common/Makefile.am
+++ b/dune/common/Makefile.am
@@ -70,6 +70,7 @@ commoninclude_HEADERS = \
shared_ptr.hh \
singleton.hh \
smallobject.hh \
+ smartptr.hh \
static_assert.hh \
stdstreams.hh \
timer.hh \
diff --git a/dune/common/smartptr.hh b/dune/common/smartptr.hh
new file mode 100644
index 000000000..7ff081dae
--- /dev/null
+++ b/dune/common/smartptr.hh
@@ -0,0 +1,107 @@
+// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+// vi: set et ts=4 sw=2 sts=2:
+#ifndef DUNE_SMARTPTR_HH
+#define DUNE_SMARTPTR_HH
+
+#include <dune/common/nullptr.hh>
+
+namespace Dune
+{
+
+ // ReferenceCountable
+ // ------------------
+
+ struct ReferenceCountable
+ {
+ ReferenceCountable ()
+ : refCount_( 0 )
+ {}
+
+ ReferenceCountable ( const ReferenceCountable &other )
+ : refCount_( 0 )
+ {}
+
+ const ReferenceCountable &operator= ( const ReferenceCountable &other )
+ {
+ return *this;
+ }
+
+ void addReference ()
+ {
+ ++refCount_;
+ }
+
+ bool removeReference ()
+ {
+ return (--refCount_ == 0);
+ }
+
+ private:
+ unsigned int refCount_;
+ };
+
+
+
+ // SmartPtr
+ // --------
+
+ template< class T >
+ struct SmartPtr
+ {
+ explicit SmartPtr ( T *ptr = nullptr )
+ : ptr_( ptr )
+ {
+ if( ptr_ )
+ ptr_->addReference();
+ }
+
+ SmartPtr ( const SmartPtr &other )
+ : ptr_( other.ptr_ )
+ {
+ if( ptr_ )
+ ptr_->addReference();
+ }
+
+ ~SmartPtr ()
+ {
+ if( ptr_ && ptr_->removeReference() )
+ delete ptr_;
+ }
+
+ const SmartPtr &operator= ( T *ptr )
+ {
+ if( ptr )
+ ptr->addReference();
+ if( ptr_ && ptr_->removeReference() )
+ delete ptr_;
+ ptr_ = ptr;
+ return *this;
+ }
+
+ const SmartPtr &operator= ( const SmartPtr &other )
+ {
+ if( other.ptr_ )
+ other.ptr_->addReference();
+ if( ptr_ && ptr_->removeReference() )
+ delete ptr_;
+ ptr_ = other.ptr_;
+ return *this;
+ }
+
+ operator bool () const { return ptr_; }
+ operator T * () const { return ptr_; }
+
+ T &operator* () const { return *ptr_; }
+ T *operator-> () const { return ptr_; }
+
+
+ bool operator== ( const SmartPtr &other ) const { return (ptr_ == other.ptr_); }
+ bool operator!= ( const SmartPtr &other ) const { return (ptr_ != other.ptr_); }
+
+ private:
+ T *ptr_;
+ };
+
+} // namespace Dune
+
+#endif // #ifndef DUNE_SMARTPTR_HH
--
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