зеркало из https://github.com/mozilla/gecko-dev.git
93 строки
2.2 KiB
C++
93 строки
2.2 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
|
|
* vim: set ts=8 sts=2 et sw=2 tw=80:
|
|
* 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/. */
|
|
|
|
#ifndef js_RefCounted_h
|
|
#define js_RefCounted_h
|
|
|
|
#include "mozilla/Atomics.h"
|
|
#include "mozilla/RefCountType.h"
|
|
|
|
#include "js/Utility.h"
|
|
|
|
// These types implement the same interface as mozilla::(Atomic)RefCounted and
|
|
// must be used instead of mozilla::(Atomic)RefCounted for everything in
|
|
// SpiderMonkey. This is because Release() needs to call js_delete, not delete.
|
|
|
|
namespace js {
|
|
|
|
template <typename T>
|
|
class RefCounted {
|
|
static const MozRefCountType DEAD = 0xffffdead;
|
|
|
|
protected:
|
|
RefCounted() : mRefCnt(0) {}
|
|
~RefCounted() { MOZ_ASSERT(mRefCnt == DEAD); }
|
|
|
|
public:
|
|
void AddRef() const {
|
|
MOZ_ASSERT(int32_t(mRefCnt) >= 0);
|
|
++mRefCnt;
|
|
}
|
|
|
|
void Release() const {
|
|
MOZ_ASSERT(int32_t(mRefCnt) > 0);
|
|
MozRefCountType cnt = --mRefCnt;
|
|
if (0 == cnt) {
|
|
#ifdef DEBUG
|
|
mRefCnt = DEAD;
|
|
#endif
|
|
js_delete(const_cast<T*>(static_cast<const T*>(this)));
|
|
}
|
|
}
|
|
|
|
private:
|
|
mutable MozRefCountType mRefCnt;
|
|
};
|
|
|
|
template <typename T>
|
|
class AtomicRefCounted {
|
|
// On 64-bit systems, if the refcount type is small (say, 32 bits), there's
|
|
// a risk that it could overflow. So require it to be large enough.
|
|
|
|
static_assert(sizeof(MozRefCountType) == sizeof(uintptr_t),
|
|
"You're at risk for ref count overflow.");
|
|
|
|
static const MozRefCountType DEAD = ~MozRefCountType(0xffff) | 0xdead;
|
|
|
|
protected:
|
|
AtomicRefCounted() = default;
|
|
~AtomicRefCounted() { MOZ_ASSERT(mRefCnt == DEAD); }
|
|
|
|
public:
|
|
void AddRef() const {
|
|
++mRefCnt;
|
|
MOZ_ASSERT(mRefCnt != DEAD);
|
|
}
|
|
|
|
void Release() const {
|
|
MOZ_ASSERT(mRefCnt != 0);
|
|
MozRefCountType cnt = --mRefCnt;
|
|
if (0 == cnt) {
|
|
#ifdef DEBUG
|
|
mRefCnt = DEAD;
|
|
#endif
|
|
js_delete(const_cast<T*>(static_cast<const T*>(this)));
|
|
}
|
|
}
|
|
|
|
bool hasOneRef() const {
|
|
MOZ_ASSERT(mRefCnt > 0);
|
|
return mRefCnt == 1;
|
|
}
|
|
|
|
private:
|
|
mutable mozilla::Atomic<MozRefCountType> mRefCnt{0};
|
|
};
|
|
|
|
} // namespace js
|
|
|
|
#endif /* js_RefCounted_h */
|