gecko-dev/js/public/SweepingAPI.h

92 строки
2.6 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_SweepingAPI_h
#define js_SweepingAPI_h
#include "js/HeapAPI.h"
namespace JS {
namespace detail {
class WeakCacheBase;
} // namespace detail
namespace shadow {
JS_PUBLIC_API(void)
RegisterWeakCache(JS::Zone* zone, JS::detail::WeakCacheBase* cachep);
JS_PUBLIC_API(void)
RegisterWeakCache(JSRuntime* rt, JS::detail::WeakCacheBase* cachep);
} // namespace shadow
namespace detail {
class WeakCacheBase : public mozilla::LinkedListElement<WeakCacheBase>
{
WeakCacheBase() = delete;
explicit WeakCacheBase(const WeakCacheBase&) = delete;
public:
explicit WeakCacheBase(Zone* zone) {
shadow::RegisterWeakCache(zone, this);
}
explicit WeakCacheBase(JSRuntime* rt) {
shadow::RegisterWeakCache(rt, this);
}
WeakCacheBase(WeakCacheBase&& other) = default;
virtual ~WeakCacheBase() {}
virtual size_t sweep() = 0;
virtual bool needsSweep() = 0;
virtual bool setNeedsIncrementalBarrier(bool needs) {
// Derived classes do not support incremental barriers by default.
return false;
}
virtual bool needsIncrementalBarrier() const {
// Derived classes do not support incremental barriers by default.
return false;
}
};
} // namespace detail
// A WeakCache stores the given Sweepable container and links itself into a
// list of such caches that are swept during each GC. A WeakCache can be
// specific to a zone, or across a whole runtime, depending on which
// constructor is used.
template <typename T>
class WeakCache : protected detail::WeakCacheBase,
public js::MutableWrappedPtrOperations<T, WeakCache<T>>
{
T cache;
public:
using Type = T;
template <typename... Args>
explicit WeakCache(Zone* zone, Args&&... args)
: WeakCacheBase(zone), cache(mozilla::Forward<Args>(args)...)
{}
template <typename... Args>
explicit WeakCache(JSRuntime* rt, Args&&... args)
: WeakCacheBase(rt), cache(mozilla::Forward<Args>(args)...)
{}
const T& get() const { return cache; }
T& get() { return cache; }
size_t sweep() override {
GCPolicy<T>::sweep(&cache);
return 0;
}
bool needsSweep() override {
return cache.needsSweep();
}
};
} // namespace JS
#endif // js_SweepingAPI_h