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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 nsRefPtrHashtable_h__
#define nsRefPtrHashtable_h__
#include "nsBaseHashtable.h"
#include "nsHashKeys.h"
#include "nsAutoPtr.h"
/**
* templated hashtable class maps keys to reference pointers.
* See nsBaseHashtable for complete declaration.
* @param KeyClass a wrapper-class for the hashtable key, see nsHashKeys.h
* for a complete specification.
* @param PtrType the reference-type being wrapped
* @see nsDataHashtable, nsClassHashtable
*/
template<class KeyClass, class PtrType>
class nsRefPtrHashtable
: public nsBaseHashtable<KeyClass, RefPtr<PtrType>, PtrType*>
{
public:
typedef typename KeyClass::KeyType KeyType;
typedef PtrType* UserDataType;
typedef nsBaseHashtable<KeyClass, RefPtr<PtrType>, PtrType*> base_type;
nsRefPtrHashtable() {}
explicit nsRefPtrHashtable(uint32_t aInitLength)
: nsBaseHashtable<KeyClass, RefPtr<PtrType>, PtrType*>(aInitLength)
{
}
/**
* @copydoc nsBaseHashtable::Get
* @param aData This is an XPCOM getter, so aData is already_addrefed.
* If the key doesn't exist, aData will be set to nullptr.
*/
bool Get(KeyType aKey, UserDataType* aData) const;
/**
* Gets a weak reference to the hashtable entry.
* @param aFound If not nullptr, will be set to true if the entry is found,
* to false otherwise.
* @return The entry, or nullptr if not found. Do not release this pointer!
*/
PtrType* GetWeak(KeyType aKey, bool* aFound = nullptr) const;
// Overload Put, rather than overriding it.
using base_type::Put;
void Put(KeyType aKey, already_AddRefed<PtrType> aData);
MOZ_MUST_USE bool Put(KeyType aKey, already_AddRefed<PtrType> aData,
const mozilla::fallible_t&);
// Overload Remove, rather than overriding it.
using base_type::Remove;
/**
* Remove the data for the associated key, swapping the current value into
* pData, thereby avoiding calls to AddRef and Release.
* @param aKey the key to remove from the hashtable
* @param aData This is an XPCOM getter, so aData is already_addrefed.
* If the key doesn't exist, aData will be set to nullptr. Must be non-null.
*/
bool Remove(KeyType aKey, UserDataType* aData);
};
template<typename K, typename T>
inline void
ImplCycleCollectionUnlink(nsRefPtrHashtable<K, T>& aField)
{
aField.Clear();
}
template<typename K, typename T>
inline void
ImplCycleCollectionTraverse(nsCycleCollectionTraversalCallback& aCallback,
nsRefPtrHashtable<K, T>& aField,
const char* aName,
uint32_t aFlags = 0)
{
for (auto iter = aField.ConstIter(); !iter.Done(); iter.Next()) {
CycleCollectionNoteChild(aCallback, iter.UserData(), aName, aFlags);
}
}
//
// nsRefPtrHashtable definitions
//
template<class KeyClass, class PtrType>
bool
nsRefPtrHashtable<KeyClass, PtrType>::Get(KeyType aKey,
UserDataType* aRefPtr) const
{
typename base_type::EntryType* ent = this->GetEntry(aKey);
if (ent) {
if (aRefPtr) {
*aRefPtr = ent->mData;
NS_IF_ADDREF(*aRefPtr);
}
return true;
}
// if the key doesn't exist, set *aRefPtr to null
// so that it is a valid XPCOM getter
if (aRefPtr) {
*aRefPtr = nullptr;
}
return false;
}
template<class KeyClass, class PtrType>
PtrType*
nsRefPtrHashtable<KeyClass, PtrType>::GetWeak(KeyType aKey, bool* aFound) const
{
typename base_type::EntryType* ent = this->GetEntry(aKey);
if (ent) {
if (aFound) {
*aFound = true;
}
return ent->mData;
}
// Key does not exist, return nullptr and set aFound to false
if (aFound) {
*aFound = false;
}
return nullptr;
}
template<class KeyClass, class PtrType>
void
nsRefPtrHashtable<KeyClass, PtrType>::Put(KeyType aKey,
already_AddRefed<PtrType> aData)
{
if (!Put(aKey, mozilla::Move(aData), mozilla::fallible)) {
NS_ABORT_OOM(this->mTable.EntrySize() * this->mTable.EntryCount());
}
}
template<class KeyClass, class PtrType>
bool
nsRefPtrHashtable<KeyClass, PtrType>::Put(KeyType aKey,
already_AddRefed<PtrType> aData,
const mozilla::fallible_t&)
{
typename base_type::EntryType* ent = this->PutEntry(aKey);
if (!ent) {
return false;
}
ent->mData = aData;
return true;
}
template<class KeyClass, class PtrType>
bool
nsRefPtrHashtable<KeyClass, PtrType>::Remove(KeyType aKey,
UserDataType* aRefPtr)
{
MOZ_ASSERT(aRefPtr);
typename base_type::EntryType* ent = this->GetEntry(aKey);
if (ent) {
ent->mData.forget(aRefPtr);
this->Remove(aKey);
return true;
}
// If the key doesn't exist, set *aRefPtr to null
// so that it is a valid XPCOM getter.
*aRefPtr = nullptr;
return false;
}
#endif // nsRefPtrHashtable_h__
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