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/* -*- 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
#ifndef DOM_SVG_SVGATTRTEAROFFTABLE_H_
#define DOM_SVG_SVGATTRTEAROFFTABLE_H_
#include "mozilla/DebugOnly.h"
#include "mozilla/StaticPtr.h"
#include "nsTHashMap.h"
#include "nsDebug.h"
#include "nsHashKeys.h"
namespace mozilla {
/**
* Global hashmap to associate internal SVG data types (e.g. SVGAnimatedLength)
* with DOM tear-off objects (e.g. DOMSVGLength). 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 SVGAttrTearoffTable {
public:
#ifdef DEBUG
~SVGAttrTearoffTable() {
NS_ASSERTION(!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:
using SimpleTypePtrKey = nsPtrHashKey<SimpleType>;
using TearoffTable = nsTHashMap<SimpleTypePtrKey, TearoffType*>;
StaticAutoPtr<TearoffTable> mTable;
};
template <class SimpleType, class TearoffType>
TearoffType* SVGAttrTearoffTable<SimpleType, TearoffType>::GetTearoff(
SimpleType* aSimple) {
if (!mTable) {
return nullptr;
}
TearoffType* tearoff = nullptr;
DebugOnly<bool> found = mTable->Get(aSimple, &tearoff);
MOZ_ASSERT(!found || tearoff,
"null pointer stored in attribute tear-off map");
return tearoff;
}
template <class SimpleType, class TearoffType>
void SVGAttrTearoffTable<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->InsertOrUpdate(aSimple, aTearoff);
}
template <class SimpleType, class TearoffType>
void SVGAttrTearoffTable<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) {
mTable = nullptr;
}
}
} // namespace mozilla
#endif // DOM_SVG_SVGATTRTEAROFFTABLE_H_