/* -*- 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_TraceableFifo_h #define js_TraceableFifo_h #include "ds/Fifo.h" #include "js/RootingAPI.h" #include "js/TracingAPI.h" namespace js { // A TraceableFifo is a Fifo with an additional trace method that knows how to // visit all of the items stored in the Fifo. For Fifos that contain GC things, // this is usually more convenient than manually iterating and marking the // contents. // // Most types of GC pointers as keys and values can be traced with no extra // infrastructure. For structs and non-gc-pointer members, ensure that there is // a specialization of GCPolicy<T> with an appropriate trace method available // to handle the custom type. Generic helpers can be found in // js/public/TracingAPI.h. Generic helpers can be found in // js/public/TracingAPI.h. // // Note that although this Fifo's trace will deal correctly with moved items, it // does not itself know when to barrier or trace items. To function properly it // must either be used with Rooted, or barriered and traced manually. template <typename T, size_t MinInlineCapacity = 0, typename AllocPolicy = TempAllocPolicy> class TraceableFifo : public js::Fifo<T, MinInlineCapacity, AllocPolicy> { using Base = js::Fifo<T, MinInlineCapacity, AllocPolicy>; public: explicit TraceableFifo(AllocPolicy alloc = AllocPolicy()) : Base(alloc) {} TraceableFifo(TraceableFifo&& rhs) : Base(mozilla::Move(rhs)) { } TraceableFifo& operator=(TraceableFifo&& rhs) { return Base::operator=(mozilla::Move(rhs)); } TraceableFifo(const TraceableFifo&) = delete; TraceableFifo& operator=(const TraceableFifo&) = delete; void trace(JSTracer* trc) { for (size_t i = 0; i < this->front_.length(); ++i) JS::GCPolicy<T>::trace(trc, &this->front_[i], "fifo element"); for (size_t i = 0; i < this->rear_.length(); ++i) JS::GCPolicy<T>::trace(trc, &this->rear_[i], "fifo element"); } }; template <typename Outer, typename T, size_t Capacity, typename AllocPolicy> class TraceableFifoOperations { using TF = TraceableFifo<T, Capacity, AllocPolicy>; const TF& fifo() const { return static_cast<const Outer*>(this)->extract(); } public: size_t length() const { return fifo().length(); } bool empty() const { return fifo().empty(); } const T& front() const { return fifo().front(); } }; template <typename Outer, typename T, size_t Capacity, typename AllocPolicy> class MutableTraceableFifoOperations : public TraceableFifoOperations<Outer, T, Capacity, AllocPolicy> { using TF = TraceableFifo<T, Capacity, AllocPolicy>; TF& fifo() { return static_cast<Outer*>(this)->extract(); } public: T& front() { return fifo().front(); } template<typename U> bool pushBack(U&& u) { return fifo().pushBack(mozilla::Forward<U>(u)); } template<typename... Args> bool emplaceBack(Args&&... args) { return fifo().emplaceBack(mozilla::Forward<Args...>(args...)); } bool popFront() { return fifo().popFront(); } void clear() { fifo().clear(); } }; template <typename A, size_t B, typename C> class RootedBase<TraceableFifo<A,B,C>> : public MutableTraceableFifoOperations<JS::Rooted<TraceableFifo<A,B,C>>, A,B,C> { using TF = TraceableFifo<A,B,C>; friend class TraceableFifoOperations<JS::Rooted<TF>, A,B,C>; const TF& extract() const { return *static_cast<const JS::Rooted<TF>*>(this)->address(); } friend class MutableTraceableFifoOperations<JS::Rooted<TF>, A,B,C>; TF& extract() { return *static_cast<JS::Rooted<TF>*>(this)->address(); } }; template <typename A, size_t B, typename C> class MutableHandleBase<TraceableFifo<A,B,C>> : public MutableTraceableFifoOperations<JS::MutableHandle<TraceableFifo<A,B,C>>, A,B,C> { using TF = TraceableFifo<A,B,C>; friend class TraceableFifoOperations<JS::MutableHandle<TF>, A,B,C>; const TF& extract() const { return *static_cast<const JS::MutableHandle<TF>*>(this)->address(); } friend class MutableTraceableFifoOperations<JS::MutableHandle<TF>, A,B,C>; TF& extract() { return *static_cast<JS::MutableHandle<TF>*>(this)->address(); } }; template <typename A, size_t B, typename C> class HandleBase<TraceableFifo<A,B,C>> : public TraceableFifoOperations<JS::Handle<TraceableFifo<A,B,C>>, A,B,C> { using TF = TraceableFifo<A,B,C>; friend class TraceableFifoOperations<JS::Handle<TF>, A,B,C>; const TF& extract() const { return *static_cast<const JS::Handle<TF>*>(this)->address(); } }; } // namespace js #endif // js_TraceableFifo_h