//////////////////////////////////////////////////////////////////////////////// // The Loki Library // Copyright (c) 2001 by Andrei Alexandrescu // This code accompanies the book: // Alexandrescu, Andrei. "Modern C++ Design: Generic Programming and Design // Patterns Applied". Copyright (c) 2001. Addison-Wesley. // Permission to use, copy, modify, distribute and sell this software for any // purpose is hereby granted without fee, provided that the above copyright // notice appear in all copies and that both that copyright notice and this // permission notice appear in supporting documentation. // The author or Addison-Wesley Longman make no representations about the // suitability of this software for any purpose. It is provided "as is" // without express or implied warranty. //////////////////////////////////////////////////////////////////////////////// #ifndef LOKI_SMARTPTR_INC_ #define LOKI_SMARTPTR_INC_ // $Header$ /// \defgroup SmartPointerGroup Smart pointers /// Policy based implementation of a smart pointer /// \defgroup SmartPointerOwnershipGroup Ownership policies /// \ingroup SmartPointerGroup /// \defgroup SmartPointerStorageGroup Storage policies /// \ingroup SmartPointerGroup /// \defgroup SmartPointerConversionGroup Conversion policies /// \ingroup SmartPointerGroup /// \defgroup SmartPointerCheckingGroup Checking policies /// \ingroup SmartPointerGroup #include "LokiExport.h" #include "SmallObj.h" #include "TypeManip.h" #include "static_check.h" #include "RefToValue.h" #include "ConstPolicy.h" #include #include #include #include #if !defined(_MSC_VER) #include #endif namespace Loki { //////////////////////////////////////////////////////////////////////////////// /// \class HeapStorage /// /// \ingroup SmartPointerStorageGroup /// Implementation of the StoragePolicy used by SmartPtr. Uses explicit call /// to T's destructor followed by call to free. //////////////////////////////////////////////////////////////////////////////// template class HeapStorage { public: typedef T* StoredType; // the type of the pointee_ object typedef T* PointerType; // type returned by operator-> typedef T& ReferenceType; // type returned by operator* HeapStorage() : pointee_(Default()) {} // The storage policy doesn't initialize the stored pointer // which will be initialized by the OwnershipPolicy's Clone fn HeapStorage(const HeapStorage&) : pointee_(0) {} template HeapStorage(const HeapStorage&) : pointee_(0) {} HeapStorage(const StoredType& p) : pointee_(p) {} PointerType operator->() const { return pointee_; } ReferenceType operator*() const { return *pointee_; } void Swap(HeapStorage& rhs) { std::swap(pointee_, rhs.pointee_); } // Accessors template friend typename HeapStorage::PointerType GetImpl(const HeapStorage& sp); template friend const typename HeapStorage::StoredType& GetImplRef(const HeapStorage& sp); template friend typename HeapStorage::StoredType& GetImplRef(HeapStorage& sp); protected: // Destroys the data stored // (Destruction might be taken over by the OwnershipPolicy) void Destroy() { if ( 0 != pointee_ ) { pointee_->~T(); ::free( pointee_ ); } } // Default value to initialize the pointer static StoredType Default() { return 0; } private: // Data StoredType pointee_; }; template inline typename HeapStorage::PointerType GetImpl(const HeapStorage& sp) { return sp.pointee_; } template inline const typename HeapStorage::StoredType& GetImplRef(const HeapStorage& sp) { return sp.pointee_; } template inline typename HeapStorage::StoredType& GetImplRef(HeapStorage& sp) { return sp.pointee_; } //////////////////////////////////////////////////////////////////////////////// /// \class DefaultSPStorage /// /// \ingroup SmartPointerStorageGroup /// Implementation of the StoragePolicy used by SmartPtr //////////////////////////////////////////////////////////////////////////////// template class DefaultSPStorage { public: typedef T* StoredType; // the type of the pointee_ object typedef T* PointerType; // type returned by operator-> typedef T& ReferenceType; // type returned by operator* DefaultSPStorage() : pointee_(Default()) {} // The storage policy doesn't initialize the stored pointer // which will be initialized by the OwnershipPolicy's Clone fn DefaultSPStorage(const DefaultSPStorage&) : pointee_(0) {} template DefaultSPStorage(const DefaultSPStorage&) : pointee_(0) {} DefaultSPStorage(const StoredType& p) : pointee_(p) {} PointerType operator->() const { return pointee_; } ReferenceType operator*() const { return *pointee_; } void Swap(DefaultSPStorage& rhs) { std::swap(pointee_, rhs.pointee_); } // Accessors template friend typename DefaultSPStorage::PointerType GetImpl(const DefaultSPStorage& sp); template friend const typename DefaultSPStorage::StoredType& GetImplRef(const DefaultSPStorage& sp); template friend typename DefaultSPStorage::StoredType& GetImplRef(DefaultSPStorage& sp); protected: // Destroys the data stored // (Destruction might be taken over by the OwnershipPolicy) void Destroy() { delete pointee_; } // Default value to initialize the pointer static StoredType Default() { return 0; } private: // Data StoredType pointee_; }; template inline typename DefaultSPStorage::PointerType GetImpl(const DefaultSPStorage& sp) { return sp.pointee_; } template inline const typename DefaultSPStorage::StoredType& GetImplRef(const DefaultSPStorage& sp) { return sp.pointee_; } template inline typename DefaultSPStorage::StoredType& GetImplRef(DefaultSPStorage& sp) { return sp.pointee_; } //////////////////////////////////////////////////////////////////////////////// /// \class ArrayStorage /// /// \ingroup SmartPointerStorageGroup /// Implementation of the ArrayStorage used by SmartPtr //////////////////////////////////////////////////////////////////////////////// template class ArrayStorage { public: typedef T* StoredType; // the type of the pointee_ object typedef T* PointerType; // type returned by operator-> typedef T& ReferenceType; // type returned by operator* ArrayStorage() : pointee_(Default()) {} // The storage policy doesn't initialize the stored pointer // which will be initialized by the OwnershipPolicy's Clone fn ArrayStorage(const ArrayStorage&) : pointee_(0) {} template ArrayStorage(const ArrayStorage&) : pointee_(0) {} ArrayStorage(const StoredType& p) : pointee_(p) {} PointerType operator->() const { return pointee_; } ReferenceType operator*() const { return *pointee_; } void Swap(ArrayStorage& rhs) { std::swap(pointee_, rhs.pointee_); } // Accessors template friend typename ArrayStorage::PointerType GetImpl(const ArrayStorage& sp); template friend const typename ArrayStorage::StoredType& GetImplRef(const ArrayStorage& sp); template friend typename ArrayStorage::StoredType& GetImplRef(ArrayStorage& sp); protected: // Destroys the data stored // (Destruction might be taken over by the OwnershipPolicy) void Destroy() { delete [] pointee_; } // Default value to initialize the pointer static StoredType Default() { return 0; } private: // Data StoredType pointee_; }; template inline typename ArrayStorage::PointerType GetImpl(const ArrayStorage& sp) { return sp.pointee_; } template inline const typename ArrayStorage::StoredType& GetImplRef(const ArrayStorage& sp) { return sp.pointee_; } template inline typename ArrayStorage::StoredType& GetImplRef(ArrayStorage& sp) { return sp.pointee_; } //////////////////////////////////////////////////////////////////////////////// /// \class RefCounted /// /// \ingroup SmartPointerOwnershipGroup /// Implementation of the OwnershipPolicy used by SmartPtr /// Provides a classic external reference counting implementation //////////////////////////////////////////////////////////////////////////////// template class RefCounted { public: RefCounted() : pCount_(static_cast( SmallObject<>::operator new(sizeof(uintptr_t)))) { assert(pCount_!=0); *pCount_ = 1; } RefCounted(const RefCounted& rhs) : pCount_(rhs.pCount_) {} // MWCW lacks template friends, hence the following kludge template RefCounted(const RefCounted& rhs) : pCount_(reinterpret_cast(rhs).pCount_) {} P Clone(const P& val) { ++*pCount_; return val; } bool Release(const P&) { if (!--*pCount_) { SmallObject<>::operator delete(pCount_, sizeof(uintptr_t)); pCount_ = NULL; return true; } return false; } void Swap(RefCounted& rhs) { std::swap(pCount_, rhs.pCount_); } enum { destructiveCopy = false }; private: // Data uintptr_t* pCount_; }; //////////////////////////////////////////////////////////////////////////////// /// \struct RefCountedMT /// /// \ingroup SmartPointerOwnershipGroup /// Implementation of the OwnershipPolicy used by SmartPtr /// Implements external reference counting for multithreaded programs /// Policy Usage: RefCountedMTAdj::RefCountedMT /// /// \par Warning /// There could be a race condition, see bug "Race condition in RefCountedMTAdj::Release" /// http://sourceforge.net/tracker/index.php?func=detail&aid=1408845&group_id=29557&atid=396644 //////////////////////////////////////////////////////////////////////////////// template