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Diffstat (limited to '')
-rw-r--r-- | js/public/GCVector.h | 366 |
1 files changed, 366 insertions, 0 deletions
diff --git a/js/public/GCVector.h b/js/public/GCVector.h new file mode 100644 index 0000000000..424f689a91 --- /dev/null +++ b/js/public/GCVector.h @@ -0,0 +1,366 @@ +/* -*- 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_GCVector_h +#define js_GCVector_h + +#include "mozilla/Assertions.h" // MOZ_ASSERT +#include "mozilla/Attributes.h" // MOZ_STACK_CLASS +#include "mozilla/MemoryReporting.h" // MallocSizeOf +#include "mozilla/Span.h" +#include "mozilla/Vector.h" + +#include <stddef.h> // size_t +#include <utility> // forward, move + +#include "js/AllocPolicy.h" +#include "js/GCPolicyAPI.h" +#include "js/RootingAPI.h" + +class JSTracer; +struct JSContext; + +namespace JS { + +// A GCVector is a Vector with an additional trace method that knows how +// to visit all of the items stored in the Vector. For vectors 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. +// +// Note that although this Vector'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 = js::TempAllocPolicy> +class GCVector { + mozilla::Vector<T, MinInlineCapacity, AllocPolicy> vector; + + public: + using ElementType = T; + + explicit GCVector(AllocPolicy alloc) : vector(std::move(alloc)) {} + GCVector() : GCVector(AllocPolicy()) {} + + GCVector(GCVector&& vec) : vector(std::move(vec.vector)) {} + + GCVector& operator=(GCVector&& vec) { + vector = std::move(vec.vector); + return *this; + } + + size_t length() const { return vector.length(); } + bool empty() const { return vector.empty(); } + size_t capacity() const { return vector.capacity(); } + + T* begin() { return vector.begin(); } + const T* begin() const { return vector.begin(); } + + T* end() { return vector.end(); } + const T* end() const { return vector.end(); } + + T& operator[](size_t i) { return vector[i]; } + const T& operator[](size_t i) const { return vector[i]; } + + T& back() { return vector.back(); } + const T& back() const { return vector.back(); } + + operator mozilla::Span<T>() { return vector; } + operator mozilla::Span<const T>() const { return vector; } + + bool initCapacity(size_t cap) { return vector.initCapacity(cap); } + [[nodiscard]] bool reserve(size_t req) { return vector.reserve(req); } + void shrinkBy(size_t amount) { return vector.shrinkBy(amount); } + void shrinkTo(size_t newLen) { return vector.shrinkTo(newLen); } + [[nodiscard]] bool growBy(size_t amount) { return vector.growBy(amount); } + [[nodiscard]] bool resize(size_t newLen) { return vector.resize(newLen); } + + void clear() { return vector.clear(); } + void clearAndFree() { return vector.clearAndFree(); } + + template <typename U> + bool append(U&& item) { + return vector.append(std::forward<U>(item)); + } + + void erase(T* it) { vector.erase(it); } + void erase(T* begin, T* end) { vector.erase(begin, end); } + template <typename Pred> + void eraseIf(Pred pred) { + vector.eraseIf(pred); + } + template <typename U> + void eraseIfEqual(const U& u) { + vector.eraseIfEqual(u); + } + + template <typename... Args> + [[nodiscard]] bool emplaceBack(Args&&... args) { + return vector.emplaceBack(std::forward<Args>(args)...); + } + + template <typename... Args> + void infallibleEmplaceBack(Args&&... args) { + vector.infallibleEmplaceBack(std::forward<Args>(args)...); + } + + template <typename U> + void infallibleAppend(U&& aU) { + return vector.infallibleAppend(std::forward<U>(aU)); + } + void infallibleAppendN(const T& aT, size_t aN) { + return vector.infallibleAppendN(aT, aN); + } + template <typename U> + void infallibleAppend(const U* aBegin, const U* aEnd) { + return vector.infallibleAppend(aBegin, aEnd); + } + template <typename U> + void infallibleAppend(const U* aBegin, size_t aLength) { + return vector.infallibleAppend(aBegin, aLength); + } + + template <typename U> + [[nodiscard]] bool appendAll(const U& aU) { + return vector.append(aU.begin(), aU.end()); + } + template <typename T2, size_t MinInlineCapacity2, typename AllocPolicy2> + [[nodiscard]] bool appendAll( + GCVector<T2, MinInlineCapacity2, AllocPolicy2>&& aU) { + return vector.appendAll(aU.begin(), aU.end()); + } + + [[nodiscard]] bool appendN(const T& val, size_t count) { + return vector.appendN(val, count); + } + + template <typename U> + [[nodiscard]] bool append(const U* aBegin, const U* aEnd) { + return vector.append(aBegin, aEnd); + } + template <typename U> + [[nodiscard]] bool append(const U* aBegin, size_t aLength) { + return vector.append(aBegin, aLength); + } + + void popBack() { return vector.popBack(); } + T popCopy() { return vector.popCopy(); } + + size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const { + return vector.sizeOfExcludingThis(mallocSizeOf); + } + + size_t sizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const { + return vector.sizeOfIncludingThis(mallocSizeOf); + } + + void trace(JSTracer* trc) { + for (auto& elem : vector) { + GCPolicy<T>::trace(trc, &elem, "vector element"); + } + } + + bool traceWeak(JSTracer* trc) { + mutableEraseIf( + [trc](T& elem) { return !GCPolicy<T>::traceWeak(trc, &elem); }); + return !empty(); + } + + // Like eraseIf, but may mutate the contents of the vector. Iterates from + // |startIndex| to the last element of the vector. + template <typename Pred> + void mutableEraseIf(Pred pred, size_t startIndex = 0) { + MOZ_ASSERT(startIndex <= length()); + + T* src = begin() + startIndex; + T* dst = src; + while (src != end()) { + if (!pred(*src)) { + if (src != dst) { + *dst = std::move(*src); + } + dst++; + } + src++; + } + + MOZ_ASSERT(dst <= end()); + shrinkBy(end() - dst); + } +}; + +// AllocPolicy is optional. It has a default value declared in TypeDecls.h +template <typename T, typename AllocPolicy> +class MOZ_STACK_CLASS StackGCVector : public GCVector<T, 8, AllocPolicy> { + public: + using Base = GCVector<T, 8, AllocPolicy>; + + private: + // Inherit constructor from GCVector. + using Base::Base; +}; + +} // namespace JS + +namespace js { + +template <typename Wrapper, typename T, size_t Capacity, typename AllocPolicy> +class WrappedPtrOperations<JS::GCVector<T, Capacity, AllocPolicy>, Wrapper> { + using Vec = JS::GCVector<T, Capacity, AllocPolicy>; + const Vec& vec() const { return static_cast<const Wrapper*>(this)->get(); } + + public: + const AllocPolicy& allocPolicy() const { return vec().allocPolicy(); } + size_t length() const { return vec().length(); } + bool empty() const { return vec().empty(); } + size_t capacity() const { return vec().capacity(); } + const T* begin() const { return vec().begin(); } + const T* end() const { return vec().end(); } + const T& back() const { return vec().back(); } + + JS::Handle<T> operator[](size_t aIndex) const { + return JS::Handle<T>::fromMarkedLocation(&vec().operator[](aIndex)); + } +}; + +template <typename Wrapper, typename T, size_t Capacity, typename AllocPolicy> +class MutableWrappedPtrOperations<JS::GCVector<T, Capacity, AllocPolicy>, + Wrapper> + : public WrappedPtrOperations<JS::GCVector<T, Capacity, AllocPolicy>, + Wrapper> { + using Vec = JS::GCVector<T, Capacity, AllocPolicy>; + const Vec& vec() const { return static_cast<const Wrapper*>(this)->get(); } + Vec& vec() { return static_cast<Wrapper*>(this)->get(); } + + public: + const AllocPolicy& allocPolicy() const { return vec().allocPolicy(); } + AllocPolicy& allocPolicy() { return vec().allocPolicy(); } + const T* begin() const { return vec().begin(); } + T* begin() { return vec().begin(); } + const T* end() const { return vec().end(); } + T* end() { return vec().end(); } + const T& back() const { return vec().back(); } + T& back() { return vec().back(); } + + JS::Handle<T> operator[](size_t aIndex) const { + return JS::Handle<T>::fromMarkedLocation(&vec().operator[](aIndex)); + } + JS::MutableHandle<T> operator[](size_t aIndex) { + return JS::MutableHandle<T>::fromMarkedLocation(&vec().operator[](aIndex)); + } + + [[nodiscard]] bool initCapacity(size_t aRequest) { + return vec().initCapacity(aRequest); + } + [[nodiscard]] bool reserve(size_t aRequest) { + return vec().reserve(aRequest); + } + void shrinkBy(size_t aIncr) { vec().shrinkBy(aIncr); } + [[nodiscard]] bool growBy(size_t aIncr) { return vec().growBy(aIncr); } + [[nodiscard]] bool resize(size_t aNewLength) { + return vec().resize(aNewLength); + } + void clear() { vec().clear(); } + void clearAndFree() { vec().clearAndFree(); } + template <typename U> + [[nodiscard]] bool append(U&& aU) { + return vec().append(std::forward<U>(aU)); + } + template <typename... Args> + [[nodiscard]] bool emplaceBack(Args&&... aArgs) { + return vec().emplaceBack(std::forward<Args>(aArgs)...); + } + template <typename... Args> + void infallibleEmplaceBack(Args&&... args) { + vec().infallibleEmplaceBack(std::forward<Args>(args)...); + } + template <typename U> + [[nodiscard]] bool appendAll(U&& aU) { + return vec().appendAll(aU); + } + [[nodiscard]] bool appendN(const T& aT, size_t aN) { + return vec().appendN(aT, aN); + } + template <typename U> + [[nodiscard]] bool append(const U* aBegin, const U* aEnd) { + return vec().append(aBegin, aEnd); + } + template <typename U> + [[nodiscard]] bool append(const U* aBegin, size_t aLength) { + return vec().append(aBegin, aLength); + } + template <typename U> + void infallibleAppend(U&& aU) { + vec().infallibleAppend(std::forward<U>(aU)); + } + void infallibleAppendN(const T& aT, size_t aN) { + vec().infallibleAppendN(aT, aN); + } + template <typename U> + void infallibleAppend(const U* aBegin, const U* aEnd) { + vec().infallibleAppend(aBegin, aEnd); + } + template <typename U> + void infallibleAppend(const U* aBegin, size_t aLength) { + vec().infallibleAppend(aBegin, aLength); + } + void popBack() { vec().popBack(); } + T popCopy() { return vec().popCopy(); } + void erase(T* aT) { vec().erase(aT); } + void erase(T* aBegin, T* aEnd) { vec().erase(aBegin, aEnd); } + template <typename Pred> + void eraseIf(Pred pred) { + vec().eraseIf(pred); + } + template <typename U> + void eraseIfEqual(const U& u) { + vec().eraseIfEqual(u); + } +}; + +template <typename Wrapper, typename T, typename AllocPolicy> +class WrappedPtrOperations<JS::StackGCVector<T, AllocPolicy>, Wrapper> + : public WrappedPtrOperations< + typename JS::StackGCVector<T, AllocPolicy>::Base, Wrapper> {}; + +template <typename Wrapper, typename T, typename AllocPolicy> +class MutableWrappedPtrOperations<JS::StackGCVector<T, AllocPolicy>, Wrapper> + : public MutableWrappedPtrOperations< + typename JS::StackGCVector<T, AllocPolicy>::Base, Wrapper> {}; + +} // namespace js + +namespace JS { + +// An automatically rooted GCVector for stack use. +template <typename T> +class RootedVector : public Rooted<StackGCVector<T>> { + using Vec = StackGCVector<T>; + using Base = Rooted<Vec>; + + public: + explicit RootedVector(JSContext* cx) : Base(cx, Vec(cx)) {} +}; + +// For use in rust code, an analog to RootedVector that doesn't require +// instances to be destroyed in LIFO order. +template <typename T> +class PersistentRootedVector : public PersistentRooted<StackGCVector<T>> { + using Vec = StackGCVector<T>; + using Base = PersistentRooted<Vec>; + + public: + explicit PersistentRootedVector(JSContext* cx) : Base(cx, Vec(cx)) {} +}; + +} // namespace JS + +#endif // js_GCVector_h |