gecko-dev/js/public/RefCounted.h
Lars T Hansen 37d3b18077 Bug 1480012 - Generalize JS shell mailbox to Wasm memories and modules. r=luke
In the old days we could only share a SharedArrayBuffer, but now we
can also share WasmMemory and WasmModule objects.  Rename the shell's
get/setSharedArrayBuffer as get/setSharedObject and generalize them to
handle the new types.

Leave the old names in place as aliases of the new names.

We rename /some/ uses of get/setSharedArrayBuffer in existing test
cases, but leave uses in test262 alone; we need to upstream those more
carefully.

--HG--
extra : rebase_source : 5ca04306a739249a70fc4aa8734b08e16d62f7d4
extra : source : fcd471c23cf3c1374541df766fd5aea0628fb2a5
2018-08-01 13:21:06 +02:00

98 lines
2.5 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sts=4 et sw=4 tw=99:
* 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. There are two reasons:
// - Release() needs to call js_delete, not delete
// - SpiderMonkey does not have MOZILLA_INTERNAL_API defined which can lead
// to ODR violations that show up as spurious leak reports when ref-counted
// types are allocated by SpiderMonkey and released by Gecko (or vice versa).
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() : mRefCnt(0) {}
~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)));
}
}
private:
mutable mozilla::Atomic<MozRefCountType> mRefCnt;
};
} // namespace js
#endif /* js_RefCounted_h */