/* -*- 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"
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 collection 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))
#ifdef JSGC_GENERATIONAL
, originalGcNumber(cx->zone()->gcNumber())
#endif
{}
template <class KeyInput, class ValueInput>
bool add(const ExclusiveContext* cx, T& table, const KeyInput& key, const ValueInput& value) {
#ifdef JSGC_GENERATIONAL
bool gcHappened = originalGcNumber != cx->zone()->gcNumber();
if (gcHappened)
addPtr = table.lookupForAdd(key);
#endif
return table.relookupOrAdd(addPtr, key, value);
}
typedef void (DependentAddPtr::* ConvertibleToBool)();
void nonNull() {}
bool found() const { return addPtr.found(); }
operator ConvertibleToBool() const { return found() ? &DependentAddPtr::nonNull : 0; }
const Entry& operator*() const { return *addPtr; }
const Entry* operator->() const { return &*addPtr; }
private:
AddPtr addPtr ;
#ifdef JSGC_GENERATIONAL
const uint64_t originalGcNumber;
#endif
DependentAddPtr() MOZ_DELETE;
DependentAddPtr(const DependentAddPtr&) MOZ_DELETE;
DependentAddPtr& operator=(const DependentAddPtr&) MOZ_DELETE;
};
} // namespace js
#endif