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2020-08-04 13:13:01 -04:00

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C++

//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose: Tools for correctly implementing & handling reference counted
// objects
//
//=============================================================================
#ifndef REFCOUNT_H
#define REFCOUNT_H
#include "../tier0/threadtools.h"
#if defined(_WIN32)
#pragma once
#endif
template <typename T>
inline void SafeAssign(T **ppInoutDst, T *pInoutSrc) {
Assert(ppInoutDst);
// Do addref before release
if (pInoutSrc) (pInoutSrc)->AddRef();
// Do addref before release
if (*ppInoutDst) (*ppInoutDst)->Release();
// Do the assignment
(*ppInoutDst) = pInoutSrc;
}
template <typename T>
inline void SafeAddRef(T *pObj) {
if (pObj) pObj->AddRef();
}
template <typename T>
inline void SafeRelease(T **ppInoutPtr) {
Assert(ppInoutPtr);
if (*ppInoutPtr) (*ppInoutPtr)->Release();
(*ppInoutPtr) = NULL;
}
//-----------------------------------------------------------------------------
// Purpose: Implement a standard reference counted interface. Use of this
// is optional insofar as all the concrete tools only
//require at compile time that the function signatures match.
//-----------------------------------------------------------------------------
class IRefCounted {
public:
virtual int AddRef() = 0;
virtual int Release() = 0;
};
//-----------------------------------------------------------------------------
// Purpose: Release a pointer and mark it NULL
//-----------------------------------------------------------------------------
template <class REFCOUNTED_ITEM_PTR>
inline int SafeRelease(REFCOUNTED_ITEM_PTR &pRef) {
// Use funny syntax so that this works on "auto pointers"
REFCOUNTED_ITEM_PTR *ppRef = &pRef;
if (*ppRef) {
int result = (*ppRef)->Release();
*ppRef = NULL;
return result;
}
return 0;
}
//-----------------------------------------------------------------------------
// Purpose: Maintain a reference across a scope
//-----------------------------------------------------------------------------
template <class T = IRefCounted>
class CAutoRef {
public:
CAutoRef(T *pRef) : m_pRef(pRef) {
if (m_pRef) m_pRef->AddRef();
}
~CAutoRef() {
if (m_pRef) m_pRef->Release();
}
private:
T *m_pRef;
};
//-----------------------------------------------------------------------------
// Purpose: Do a an inline AddRef then return the pointer, useful when
// returning an object from a function
//-----------------------------------------------------------------------------
#define RetAddRef(p) ((p)->AddRef(), (p))
#define InlineAddRef(p) ((p)->AddRef(), (p))
//-----------------------------------------------------------------------------
// Purpose: A class to both hold a pointer to an object and its reference.
// Base exists to support other cleanup models
//-----------------------------------------------------------------------------
template <class T>
class CBaseAutoPtr {
public:
CBaseAutoPtr() : m_pObject(0) {}
CBaseAutoPtr(T *pFrom) : m_pObject(pFrom) {}
operator const void *() const { return m_pObject; }
operator void *() { return m_pObject; }
operator const T *() const { return m_pObject; }
operator const T *() { return m_pObject; }
operator T *() { return m_pObject; }
int operator=(int i) {
AssertMsg(i == 0, "Only NULL allowed on integer assign");
m_pObject = 0;
return 0;
}
T *operator=(T *p) {
m_pObject = p;
return p;
}
bool operator!() const { return (!m_pObject); }
bool operator!=(int i) const {
AssertMsg(i == 0, "Only NULL allowed on integer compare");
return (m_pObject != NULL);
}
bool operator==(const void *p) const { return (m_pObject == p); }
bool operator!=(const void *p) const { return (m_pObject != p); }
bool operator==(T *p) const { return operator==((void *)p); }
bool operator!=(T *p) const { return operator!=((void *)p); }
bool operator==(const CBaseAutoPtr<T> &p) const {
return operator==((const void *)p);
}
bool operator!=(const CBaseAutoPtr<T> &p) const {
return operator!=((const void *)p);
}
T *operator->() { return m_pObject; }
T &operator*() { return *m_pObject; }
T **operator&() { return &m_pObject; }
const T *operator->() const { return m_pObject; }
const T &operator*() const { return *m_pObject; }
T *const *operator&() const { return &m_pObject; }
protected:
CBaseAutoPtr(const CBaseAutoPtr<T> &from) : m_pObject(from.m_pObject) {}
void operator=(const CBaseAutoPtr<T> &from) { m_pObject = from.m_pObject; }
T *m_pObject;
};
//---------------------------------------------------------
template <class T>
class CRefPtr : public CBaseAutoPtr<T> {
typedef CBaseAutoPtr<T> BaseClass;
public:
CRefPtr() {}
CRefPtr(T *pInit) : BaseClass(pInit) {}
CRefPtr(const CRefPtr<T> &from) : BaseClass(from) {}
~CRefPtr() {
if (BaseClass::m_pObject) BaseClass::m_pObject->Release();
}
void operator=(const CRefPtr<T> &from) { BaseClass::operator=(from); }
int operator=(int i) { return BaseClass::operator=(i); }
T *operator=(T *p) { return BaseClass::operator=(p); }
operator bool() const { return !BaseClass::operator!(); }
operator bool() { return !BaseClass::operator!(); }
void SafeRelease() {
if (BaseClass::m_pObject) BaseClass::m_pObject->Release();
BaseClass::m_pObject = 0;
}
void AssignAddRef(T *pFrom) {
SafeRelease();
if (pFrom) pFrom->AddRef();
BaseClass::m_pObject = pFrom;
}
void AddRefAssignTo(T *&pTo) {
::SafeRelease(pTo);
if (BaseClass::m_pObject) BaseClass::m_pObject->AddRef();
pTo = BaseClass::m_pObject;
}
};
//-----------------------------------------------------------------------------
// Purpose: Traits classes defining reference count threading model
//-----------------------------------------------------------------------------
class CRefMT {
public:
static int Increment(int *p) {
return ThreadInterlockedIncrement((long *)p);
}
static int Decrement(int *p) {
return ThreadInterlockedDecrement((long *)p);
}
};
class CRefST {
public:
static int Increment(int *p) { return ++(*p); }
static int Decrement(int *p) { return --(*p); }
};
//-----------------------------------------------------------------------------
// Purpose: Actual reference counting implementation. Pulled out to reduce
// code bloat.
//-----------------------------------------------------------------------------
template <const bool bSelfDelete, typename CRefThreading = CRefMT>
class NO_VTABLE CRefCountServiceBase {
protected:
CRefCountServiceBase() : m_iRefs(1) {}
virtual ~CRefCountServiceBase() {}
virtual bool OnFinalRelease() { return true; }
int GetRefCount() const { return m_iRefs; }
int DoAddRef() { return CRefThreading::Increment(&m_iRefs); }
int DoRelease() {
int result = CRefThreading::Decrement(&m_iRefs);
if (result) return result;
if (OnFinalRelease() && bSelfDelete) delete this;
return 0;
}
private:
int m_iRefs;
};
class CRefCountServiceNull {
protected:
static int DoAddRef() { return 1; }
static int DoRelease() { return 1; }
};
template <typename CRefThreading = CRefMT>
class NO_VTABLE CRefCountServiceDestruct {
protected:
CRefCountServiceDestruct() : m_iRefs(1) {}
virtual ~CRefCountServiceDestruct() {}
int GetRefCount() const { return m_iRefs; }
int DoAddRef() { return CRefThreading::Increment(&m_iRefs); }
int DoRelease() {
int result = CRefThreading::Decrement(&m_iRefs);
if (result) return result;
this->~CRefCountServiceDestruct();
return 0;
}
private:
int m_iRefs;
};
typedef CRefCountServiceBase<true, CRefST> CRefCountServiceST;
typedef CRefCountServiceBase<false, CRefST> CRefCountServiceNoDeleteST;
typedef CRefCountServiceBase<true, CRefMT> CRefCountServiceMT;
typedef CRefCountServiceBase<false, CRefMT> CRefCountServiceNoDeleteMT;
// Default to threadsafe
typedef CRefCountServiceNoDeleteMT CRefCountServiceNoDelete;
typedef CRefCountServiceMT CRefCountService;
//-----------------------------------------------------------------------------
// Purpose: Base classes to implement reference counting
//-----------------------------------------------------------------------------
template <class REFCOUNT_SERVICE = CRefCountService>
class NO_VTABLE CRefCounted : public REFCOUNT_SERVICE {
public:
virtual ~CRefCounted() {}
int AddRef() { return REFCOUNT_SERVICE::DoAddRef(); }
int Release() { return REFCOUNT_SERVICE::DoRelease(); }
};
//-------------------------------------
template <class BASE1, class REFCOUNT_SERVICE = CRefCountService>
class NO_VTABLE CRefCounted1 : public BASE1, public REFCOUNT_SERVICE {
public:
virtual ~CRefCounted1() {}
int AddRef() { return REFCOUNT_SERVICE::DoAddRef(); }
int Release() { return REFCOUNT_SERVICE::DoRelease(); }
};
//-------------------------------------
template <class BASE1, class BASE2, class REFCOUNT_SERVICE = CRefCountService>
class NO_VTABLE CRefCounted2 : public BASE1,
public BASE2,
public REFCOUNT_SERVICE {
public:
virtual ~CRefCounted2() {}
int AddRef() { return REFCOUNT_SERVICE::DoAddRef(); }
int Release() { return REFCOUNT_SERVICE::DoRelease(); }
};
//-------------------------------------
template <class BASE1, class BASE2, class BASE3,
class REFCOUNT_SERVICE = CRefCountService>
class NO_VTABLE CRefCounted3 : public BASE1,
public BASE2,
public BASE3,
public REFCOUNT_SERVICE {
virtual ~CRefCounted3() {}
int AddRef() { return REFCOUNT_SERVICE::DoAddRef(); }
int Release() { return REFCOUNT_SERVICE::DoRelease(); }
};
//-------------------------------------
template <class BASE1, class BASE2, class BASE3, class BASE4,
class REFCOUNT_SERVICE = CRefCountService>
class NO_VTABLE CRefCounted4 : public BASE1,
public BASE2,
public BASE3,
public BASE4,
public REFCOUNT_SERVICE {
public:
virtual ~CRefCounted4() {}
int AddRef() { return REFCOUNT_SERVICE::DoAddRef(); }
int Release() { return REFCOUNT_SERVICE::DoRelease(); }
};
//-------------------------------------
template <class BASE1, class BASE2, class BASE3, class BASE4, class BASE5,
class REFCOUNT_SERVICE = CRefCountService>
class NO_VTABLE CRefCounted5 : public BASE1,
public BASE2,
public BASE3,
public BASE4,
public BASE5,
public REFCOUNT_SERVICE {
public:
virtual ~CRefCounted5() {}
int AddRef() { return REFCOUNT_SERVICE::DoAddRef(); }
int Release() { return REFCOUNT_SERVICE::DoRelease(); }
};
//-----------------------------------------------------------------------------
// Purpose: Class to throw around a reference counted item to debug
// referencing problems
//-----------------------------------------------------------------------------
template <class BASE_REFCOUNTED, int FINAL_REFS, const char *pszName>
class CRefDebug : public BASE_REFCOUNTED {
public:
#ifdef _DEBUG
CRefDebug() {
AssertMsg(this->GetRefCount() == 1, "Expected initial ref count of 1");
DevMsg("%s:create 0x%x\n", (pszName) ? pszName : "", this);
}
virtual ~CRefDebug() {
AssertDevMsg(this->GetRefCount() == FINAL_REFS,
"Object still referenced on destroy?");
DevMsg("%s:destroy 0x%x\n", (pszName) ? pszName : "", this);
}
int AddRef() {
DevMsg("%s:(0x%x)->AddRef() --> %d\n", (pszName) ? pszName : "", this,
this->GetRefCount() + 1);
return BASE_REFCOUNTED::AddRef();
}
int Release() {
DevMsg("%s:(0x%x)->Release() --> %d\n", (pszName) ? pszName : "", this,
this->GetRefCount() - 1);
Assert(this->GetRefCount() > 0);
return BASE_REFCOUNTED::Release();
}
#endif
};
//-----------------------------------------------------------------------------
#endif // REFCOUNT_H