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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 nsInterfaceHashtable_h__
#define nsInterfaceHashtable_h__
#include "nsBaseHashtable.h"
#include "nsHashKeys.h"
#include "nsCOMPtr.h"
/**
* templated hashtable class maps keys to interface pointers.
* See nsBaseHashtable for complete declaration.
* @param KeyClass a wrapper-class for the hashtable key, see nsHashKeys.h
* for a complete specification.
* @param Interface the interface-type being wrapped
* @see nsDataHashtable, nsClassHashtable
*/
template<class KeyClass, class Interface>
class nsInterfaceHashtable
: public nsBaseHashtable<KeyClass, nsCOMPtr<Interface>, Interface*>
{
public:
typedef typename KeyClass::KeyType KeyType;
typedef Interface* UserDataType;
typedef nsBaseHashtable<KeyClass, nsCOMPtr<Interface>, Interface*> base_type;
nsInterfaceHashtable() {}
explicit nsInterfaceHashtable(uint32_t aInitLength)
: nsBaseHashtable<KeyClass, nsCOMPtr<Interface>, Interface*>(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;
/**
* @copydoc nsBaseHashtable::Get
*/
already_AddRefed<Interface> Get(KeyType aKey) 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!
*/
Interface* GetWeak(KeyType aKey, bool* aFound = nullptr) const;
};
template<typename K, typename T>
inline void
ImplCycleCollectionUnlink(nsInterfaceHashtable<K, T>& aField)
{
aField.Clear();
}
template<typename K, typename T>
inline void
ImplCycleCollectionTraverse(nsCycleCollectionTraversalCallback& aCallback,
const nsInterfaceHashtable<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);
}
}
//
// nsInterfaceHashtable definitions
//
template<class KeyClass, class Interface>
bool
nsInterfaceHashtable<KeyClass, Interface>::Get(KeyType aKey,
UserDataType* aInterface) const
{
typename base_type::EntryType* ent = this->GetEntry(aKey);
if (ent) {
if (aInterface) {
*aInterface = ent->mData;
NS_IF_ADDREF(*aInterface);
}
return true;
}
// if the key doesn't exist, set *aInterface to null
// so that it is a valid XPCOM getter
if (aInterface) {
*aInterface = nullptr;
}
return false;
}
template<class KeyClass, class Interface>
already_AddRefed<Interface>
nsInterfaceHashtable<KeyClass, Interface>::Get(KeyType aKey) const
{
typename base_type::EntryType* ent = this->GetEntry(aKey);
if (!ent) {
return nullptr;
}
nsCOMPtr<Interface> copy = ent->mData;
return copy.forget();
}
template<class KeyClass, class Interface>
Interface*
nsInterfaceHashtable<KeyClass, Interface>::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;
}
#endif // nsInterfaceHashtable_h__
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