/* -*- 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 jshashutil_h #define jshashutil_h #include "jscntxt.h" #include "gc/Zone.h" namespace js { /* * Used to add entries to a js::HashMap or HashSet where the key depends on a GC * thing that may be moved by generational or compacting GC between the call to * lookupForAdd() and relookupOrAdd(). */ template <class T> struct DependentAddPtr { typedef typename T::AddPtr AddPtr; typedef typename T::Entry Entry; template <class Lookup> DependentAddPtr(const ExclusiveContext* cx, const T& table, const Lookup& lookup) : addPtr(table.lookupForAdd(lookup)) , originalGcNumber(cx->zone()->gcNumber()) {} DependentAddPtr(DependentAddPtr&& other) : addPtr(other.addPtr) , originalGcNumber(other.originalGcNumber) {} template <class KeyInput, class ValueInput> bool add(ExclusiveContext* cx, T& table, const KeyInput& key, const ValueInput& value) { refreshAddPtr(cx, table, key); if (!table.relookupOrAdd(addPtr, key, value)) { ReportOutOfMemory(cx); return false; } return true; } template <class KeyInput> void remove(ExclusiveContext* cx, T& table, const KeyInput& key) { refreshAddPtr(cx, table, key); table.remove(addPtr); } bool found() const { return addPtr.found(); } explicit operator bool() const { return found(); } const Entry& operator*() const { return *addPtr; } const Entry* operator->() const { return &*addPtr; } private: AddPtr addPtr ; const uint64_t originalGcNumber; template <class KeyInput> void refreshAddPtr(ExclusiveContext* cx, T& table, const KeyInput& key) { bool gcHappened = originalGcNumber != cx->zone()->gcNumber(); if (gcHappened) addPtr = table.lookupForAdd(key); } DependentAddPtr() = delete; DependentAddPtr(const DependentAddPtr&) = delete; DependentAddPtr& operator=(const DependentAddPtr&) = delete; }; template <typename T, typename Lookup> inline auto MakeDependentAddPtr(const ExclusiveContext* cx, T& table, const Lookup& lookup) -> DependentAddPtr<typename mozilla::RemoveReference<decltype(table)>::Type> { using Ptr = DependentAddPtr<typename mozilla::RemoveReference<decltype(table)>::Type>; return Ptr(cx, table, lookup); } } // namespace js #endif