gecko-dev/js/public/SweepingAPI.h

61 lines
1.6 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 {
template <typename T> class WeakCache;
namespace shadow {
JS_PUBLIC_API(void)
RegisterWeakCache(JS::Zone* zone, JS::WeakCache<void*>* cachep);
} // namespace shadow
// A WeakCache stores the given Sweepable container and links itself into a
// list of such caches that are swept during each GC.
template <typename T>
class WeakCache : public js::MutableWrappedPtrOperations<T, WeakCache<T>>,
private mozilla::LinkedListElement<WeakCache<T>>
{
friend class mozilla::LinkedListElement<WeakCache<T>>;
friend class mozilla::LinkedList<WeakCache<T>>;
WeakCache() = delete;
WeakCache(const WeakCache&) = delete;
using SweepFn = void (*)(T*);
SweepFn sweeper;
T cache;
public:
using Type = T;
template <typename U>
WeakCache(Zone* zone, U&& initial)
: cache(mozilla::Forward<U>(initial))
{
sweeper = GCPolicy<T>::sweep;
shadow::RegisterWeakCache(zone, reinterpret_cast<WeakCache<void*>*>(this));
}
WeakCache(WeakCache&& other)
: sweeper(other.sweeper),
cache(mozilla::Move(other.cache))
{
}
const T& get() const { return cache; }
T& get() { return cache; }
void sweep() { sweeper(&cache); }
};
} // namespace JS
#endif // js_SweepingAPI_h