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Diffstat (limited to 'contrib/llvm/include/llvm/ADT/IntrusiveRefCntPtr.h')
-rw-r--r-- | contrib/llvm/include/llvm/ADT/IntrusiveRefCntPtr.h | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/contrib/llvm/include/llvm/ADT/IntrusiveRefCntPtr.h b/contrib/llvm/include/llvm/ADT/IntrusiveRefCntPtr.h new file mode 100644 index 0000000..37d4ac9 --- /dev/null +++ b/contrib/llvm/include/llvm/ADT/IntrusiveRefCntPtr.h @@ -0,0 +1,230 @@ +//== llvm/ADT/IntrusiveRefCntPtr.h - Smart Refcounting Pointer ---*- C++ -*-==// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file defines IntrusiveRefCntPtr, a template class that +// implements a "smart" pointer for objects that maintain their own +// internal reference count, and RefCountedBase/RefCountedBaseVPTR, two +// generic base classes for objects that wish to have their lifetimes +// managed using reference counting. +// +// IntrusiveRefCntPtr is similar to Boost's intrusive_ptr with added +// LLVM-style casting. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_ADT_INTRUSIVE_REF_CNT_PTR +#define LLVM_ADT_INTRUSIVE_REF_CNT_PTR + +#include <cassert> + +#include "llvm/Support/Casting.h" + +namespace llvm { + + template <class T> + class IntrusiveRefCntPtr; + +//===----------------------------------------------------------------------===// +/// RefCountedBase - A generic base class for objects that wish to +/// have their lifetimes managed using reference counts. Classes +/// subclass RefCountedBase to obtain such functionality, and are +/// typically handled with IntrusivePtr "smart pointers" (see below) +/// which automatically handle the management of reference counts. +/// Objects that subclass RefCountedBase should not be allocated on +/// the stack, as invoking "delete" (which is called when the +/// reference count hits 0) on such objects is an error. +//===----------------------------------------------------------------------===// + template <class Derived> + class RefCountedBase { + unsigned ref_cnt; + + protected: + RefCountedBase() : ref_cnt(0) {} + + void Retain() { ++ref_cnt; } + void Release() { + assert (ref_cnt > 0 && "Reference count is already zero."); + if (--ref_cnt == 0) delete static_cast<Derived*>(this); + } + + friend class IntrusiveRefCntPtr<Derived>; + }; + +//===----------------------------------------------------------------------===// +/// RefCountedBaseVPTR - A class that has the same function as +/// RefCountedBase, but with a virtual destructor. Should be used +/// instead of RefCountedBase for classes that already have virtual +/// methods to enforce dynamic allocation via 'new'. Classes that +/// inherit from RefCountedBaseVPTR can't be allocated on stack - +/// attempting to do this will produce a compile error. +//===----------------------------------------------------------------------===// + template <class Derived> + class RefCountedBaseVPTR { + unsigned ref_cnt; + + protected: + RefCountedBaseVPTR() : ref_cnt(0) {} + virtual ~RefCountedBaseVPTR() {} + + void Retain() { ++ref_cnt; } + void Release() { + assert (ref_cnt > 0 && "Reference count is already zero."); + if (--ref_cnt == 0) delete this; + } + + friend class IntrusiveRefCntPtr<Derived>; + }; + +//===----------------------------------------------------------------------===// +/// IntrusiveRefCntPtr - A template class that implements a "smart pointer" +/// that assumes the wrapped object has a reference count associated +/// with it that can be managed via calls to +/// IntrusivePtrAddRef/IntrusivePtrRelease. The smart pointers +/// manage reference counts via the RAII idiom: upon creation of +/// smart pointer the reference count of the wrapped object is +/// incremented and upon destruction of the smart pointer the +/// reference count is decremented. This class also safely handles +/// wrapping NULL pointers. +/// +/// Reference counting is implemented via calls to +/// Obj->Retain()/Obj->Release(). Release() is required to destroy +/// the object when the reference count reaches zero. Inheriting from +/// RefCountedBase/RefCountedBaseVPTR takes care of this +/// automatically. +//===----------------------------------------------------------------------===// + template <typename T> + class IntrusiveRefCntPtr { + T* Obj; + typedef IntrusiveRefCntPtr this_type; + public: + typedef T element_type; + + explicit IntrusiveRefCntPtr() : Obj(0) {} + + explicit IntrusiveRefCntPtr(T* obj) : Obj(obj) { + retain(); + } + + IntrusiveRefCntPtr(const IntrusiveRefCntPtr& S) : Obj(S.Obj) { + retain(); + } + + template <class X> + IntrusiveRefCntPtr(const IntrusiveRefCntPtr<X>& S) + : Obj(S.getPtr()) { + retain(); + } + + IntrusiveRefCntPtr& operator=(const IntrusiveRefCntPtr& S) { + replace(S.getPtr()); + return *this; + } + + template <class X> + IntrusiveRefCntPtr& operator=(const IntrusiveRefCntPtr<X>& S) { + replace(S.getPtr()); + return *this; + } + + IntrusiveRefCntPtr& operator=(T * S) { + replace(S); + return *this; + } + + ~IntrusiveRefCntPtr() { release(); } + + T& operator*() const { return *Obj; } + + T* operator->() const { return Obj; } + + T* getPtr() const { return Obj; } + + typedef T* (IntrusiveRefCntPtr::*unspecified_bool_type) () const; + operator unspecified_bool_type() const { + return Obj == 0 ? 0 : &IntrusiveRefCntPtr::getPtr; + } + + void swap(IntrusiveRefCntPtr& other) { + T* tmp = other.Obj; + other.Obj = Obj; + Obj = tmp; + } + + private: + void retain() { if (Obj) Obj->Retain(); } + void release() { if (Obj) Obj->Release(); } + + void replace(T* S) { + this_type(S).swap(*this); + } + }; + + template<class T, class U> + inline bool operator==(const IntrusiveRefCntPtr<T>& A, + const IntrusiveRefCntPtr<U>& B) + { + return A.getPtr() == B.getPtr(); + } + + template<class T, class U> + inline bool operator!=(const IntrusiveRefCntPtr<T>& A, + const IntrusiveRefCntPtr<U>& B) + { + return A.getPtr() != B.getPtr(); + } + + template<class T, class U> + inline bool operator==(const IntrusiveRefCntPtr<T>& A, + U* B) + { + return A.getPtr() == B; + } + + template<class T, class U> + inline bool operator!=(const IntrusiveRefCntPtr<T>& A, + U* B) + { + return A.getPtr() != B; + } + + template<class T, class U> + inline bool operator==(T* A, + const IntrusiveRefCntPtr<U>& B) + { + return A == B.getPtr(); + } + + template<class T, class U> + inline bool operator!=(T* A, + const IntrusiveRefCntPtr<U>& B) + { + return A != B.getPtr(); + } + +//===----------------------------------------------------------------------===// +// LLVM-style downcasting support for IntrusiveRefCntPtr objects +//===----------------------------------------------------------------------===// + + template<class T> struct simplify_type<IntrusiveRefCntPtr<T> > { + typedef T* SimpleType; + static SimpleType getSimplifiedValue(const IntrusiveRefCntPtr<T>& Val) { + return Val.getPtr(); + } + }; + + template<class T> struct simplify_type<const IntrusiveRefCntPtr<T> > { + typedef T* SimpleType; + static SimpleType getSimplifiedValue(const IntrusiveRefCntPtr<T>& Val) { + return Val.getPtr(); + } + }; + +} // end namespace llvm + +#endif // LLVM_ADT_INTRUSIVE_REF_CNT_PTR |