tenfourfox/dom/svg/nsSVGAttrTearoffTable.h

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2017-04-19 07:56:45 +00:00
/* -*- 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 NS_SVGATTRTEAROFFTABLE_H_
#define NS_SVGATTRTEAROFFTABLE_H_
#include "nsDataHashtable.h"
#include "nsDebug.h"
#include "nsHashKeys.h"
/**
* Global hashmap to associate internal SVG data types (e.g. nsSVGLength2) with
* DOM tear-off objects (e.g. nsIDOMSVGLength). This allows us to always return
* the same object for subsequent requests for DOM objects.
*
* We don't keep an owning reference to the tear-off objects so they are
* responsible for removing themselves from this table when they die.
*/
template<class SimpleType, class TearoffType>
class nsSVGAttrTearoffTable
{
public:
#ifdef DEBUG
~nsSVGAttrTearoffTable()
{
MOZ_ASSERT(!mTable, "Tear-off objects remain in hashtable at shutdown.");
}
#endif
TearoffType* GetTearoff(SimpleType* aSimple);
void AddTearoff(SimpleType* aSimple, TearoffType* aTearoff);
void RemoveTearoff(SimpleType* aSimple);
private:
typedef nsPtrHashKey<SimpleType> SimpleTypePtrKey;
typedef nsDataHashtable<SimpleTypePtrKey, TearoffType* > TearoffTable;
TearoffTable* mTable;
};
template<class SimpleType, class TearoffType>
TearoffType*
nsSVGAttrTearoffTable<SimpleType, TearoffType>::GetTearoff(SimpleType* aSimple)
{
if (!mTable)
return nullptr;
TearoffType *tearoff = nullptr;
#ifdef DEBUG
bool found =
#endif
mTable->Get(aSimple, &tearoff);
MOZ_ASSERT(!found || tearoff,
"null pointer stored in attribute tear-off map");
return tearoff;
}
template<class SimpleType, class TearoffType>
void
nsSVGAttrTearoffTable<SimpleType, TearoffType>::AddTearoff(SimpleType* aSimple,
TearoffType* aTearoff)
{
if (!mTable) {
mTable = new TearoffTable;
}
// We shouldn't be adding a tear-off if there already is one. If that happens,
// something is wrong.
if (mTable->Get(aSimple, nullptr)) {
MOZ_ASSERT(false, "There is already a tear-off for this object.");
return;
}
mTable->Put(aSimple, aTearoff);
}
template<class SimpleType, class TearoffType>
void
nsSVGAttrTearoffTable<SimpleType, TearoffType>::RemoveTearoff(
SimpleType* aSimple)
{
if (!mTable) {
// Perhaps something happened in between creating the SimpleType object and
// registering it
return;
}
mTable->Remove(aSimple);
if (mTable->Count() == 0) {
delete mTable;
mTable = nullptr;
}
}
#endif // NS_SVGATTRTEAROFFTABLE_H_