mirror of
https://github.com/classilla/tenfourfox.git
synced 2024-09-10 11:54:40 +00:00
133 lines
4.0 KiB
C++
133 lines
4.0 KiB
C++
/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
|
|
* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
|
|
// This header provides virtual, non-templated alternatives to MFBT's RefCounted<T>.
|
|
// It intentionally uses MFBT coding style with the intention of moving there
|
|
// should there be other use cases for it.
|
|
|
|
#ifndef MOZILLA_GENERICREFCOUNTED_H_
|
|
#define MOZILLA_GENERICREFCOUNTED_H_
|
|
|
|
#include "mozilla/RefPtr.h"
|
|
#include "mozilla/RefCounted.h"
|
|
|
|
namespace mozilla {
|
|
|
|
/**
|
|
* Common base class for GenericRefCounted and GenericAtomicRefCounted.
|
|
*
|
|
* Having this shared base class, common to both the atomic and non-atomic
|
|
* cases, allows to have RefPtr's that don't care about whether the
|
|
* objects they're managing have atomic refcounts or not.
|
|
*/
|
|
class GenericRefCountedBase
|
|
{
|
|
protected:
|
|
virtual ~GenericRefCountedBase() {};
|
|
|
|
public:
|
|
// AddRef() and Release() method names are for compatibility with nsRefPtr.
|
|
virtual void AddRef() = 0;
|
|
|
|
virtual void Release() = 0;
|
|
|
|
// ref() and deref() method names are for compatibility with wtf::RefPtr.
|
|
// No virtual keywords here: if a subclass wants to override the refcounting
|
|
// mechanism, it is welcome to do so by overriding AddRef() and Release().
|
|
void ref() { AddRef(); }
|
|
void deref() { Release(); }
|
|
|
|
#ifdef MOZ_REFCOUNTED_LEAK_CHECKING
|
|
virtual const char* typeName() const = 0;
|
|
virtual size_t typeSize() const = 0;
|
|
#endif
|
|
};
|
|
|
|
namespace detail {
|
|
|
|
template<RefCountAtomicity Atomicity>
|
|
class GenericRefCounted : public GenericRefCountedBase
|
|
{
|
|
protected:
|
|
GenericRefCounted() : refCnt(0) { }
|
|
|
|
virtual ~GenericRefCounted() {
|
|
MOZ_ASSERT(refCnt == detail::DEAD);
|
|
}
|
|
|
|
public:
|
|
virtual void AddRef() override {
|
|
// Note: this method must be thread safe for GenericAtomicRefCounted.
|
|
MOZ_ASSERT(int32_t(refCnt) >= 0);
|
|
#ifndef MOZ_REFCOUNTED_LEAK_CHECKING
|
|
++refCnt;
|
|
#else
|
|
const char* type = typeName();
|
|
uint32_t size = typeSize();
|
|
const void* ptr = this;
|
|
MozRefCountType cnt = ++refCnt;
|
|
detail::RefCountLogger::logAddRef(ptr, cnt, type, size);
|
|
#endif
|
|
}
|
|
|
|
virtual void Release() override {
|
|
// Note: this method must be thread safe for GenericAtomicRefCounted.
|
|
MOZ_ASSERT(int32_t(refCnt) > 0);
|
|
#ifndef MOZ_REFCOUNTED_LEAK_CHECKING
|
|
MozRefCountType cnt = --refCnt;
|
|
#else
|
|
const char* type = typeName();
|
|
const void* ptr = this;
|
|
MozRefCountType cnt = --refCnt;
|
|
// Note: it's not safe to touch |this| after decrementing the refcount,
|
|
// except for below.
|
|
detail::RefCountLogger::logRelease(ptr, cnt, type);
|
|
#endif
|
|
if (0 == cnt) {
|
|
// Because we have atomically decremented the refcount above, only
|
|
// one thread can get a 0 count here, so as long as we can assume that
|
|
// everything else in the system is accessing this object through
|
|
// RefPtrs, it's safe to access |this| here.
|
|
#ifdef DEBUG
|
|
refCnt = detail::DEAD;
|
|
#endif
|
|
delete this;
|
|
}
|
|
}
|
|
|
|
MozRefCountType refCount() const { return refCnt; }
|
|
bool hasOneRef() const {
|
|
MOZ_ASSERT(refCnt > 0);
|
|
return refCnt == 1;
|
|
}
|
|
|
|
private:
|
|
typename Conditional<Atomicity == AtomicRefCount, Atomic<MozRefCountType>, MozRefCountType>::Type refCnt;
|
|
};
|
|
|
|
} // namespace detail
|
|
|
|
/**
|
|
* This reference-counting base class is virtual instead of
|
|
* being templated, which is useful in cases where one needs
|
|
* genericity at binary code level, but comes at the cost
|
|
* of a moderate performance and size overhead, like anything virtual.
|
|
*/
|
|
class GenericRefCounted : public detail::GenericRefCounted<detail::NonAtomicRefCount>
|
|
{
|
|
};
|
|
|
|
/**
|
|
* GenericAtomicRefCounted is like GenericRefCounted, with an atomically updated
|
|
* reference counter.
|
|
*/
|
|
class GenericAtomicRefCounted : public detail::GenericRefCounted<detail::AtomicRefCount>
|
|
{
|
|
};
|
|
|
|
} // namespace mozilla
|
|
|
|
#endif
|