gecko-dev/xpcom/glue/nsInterfaceHashtable.h

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/* -*- Mode: C++; tab-width: 2; 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;
/**
* @copydoc nsBaseHashtable::Get
* @param pData This is an XPCOM getter, so pData is already_addrefed.
* If the key doesn't exist, pData will be set to nullptr.
*/
bool Get(KeyType aKey, UserDataType* pData) 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;
};
/**
* Thread-safe version of nsInterfaceHashtable
* @param KeyClass a wrapper-class for the hashtable key, see nsHashKeys.h
* for a complete specification.
* @param Interface the interface-type being wrapped
*/
template<class KeyClass,class Interface>
class nsInterfaceHashtableMT :
public nsBaseHashtableMT< KeyClass, nsCOMPtr<Interface> , Interface* >
{
public:
typedef typename KeyClass::KeyType KeyType;
typedef Interface* UserDataType;
typedef nsBaseHashtableMT< KeyClass, nsCOMPtr<Interface> , Interface* >
base_type;
/**
* @copydoc nsBaseHashtable::Get
* @param pData This is an XPCOM getter, so pData is already_addrefed.
* If the key doesn't exist, pData will be set to nullptr.
*/
bool Get(KeyType aKey, UserDataType* pData) const;
// GetWeak does not make sense on a multi-threaded hashtable, where another
// thread may remove the entry (and hence release it) as soon as GetWeak
// returns
};
//
// nsInterfaceHashtable definitions
//
template<class KeyClass,class Interface>
bool
nsInterfaceHashtable<KeyClass,Interface>::Get
(KeyType aKey, UserDataType* pInterface) const
{
typename base_type::EntryType* ent = this->GetEntry(aKey);
if (ent)
{
if (pInterface)
{
*pInterface = ent->mData;
NS_IF_ADDREF(*pInterface);
}
return true;
}
// if the key doesn't exist, set *pInterface to null
// so that it is a valid XPCOM getter
if (pInterface)
*pInterface = 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 NULL;
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;
}
//
// nsInterfaceHashtableMT definitions
//
template<class KeyClass,class Interface>
bool
nsInterfaceHashtableMT<KeyClass,Interface>::Get
(KeyType aKey, UserDataType* pInterface) const
{
PR_Lock(this->mLock);
typename base_type::EntryType* ent = this->GetEntry(aKey);
if (ent)
{
if (pInterface)
{
*pInterface = ent->mData;
NS_IF_ADDREF(*pInterface);
}
PR_Unlock(this->mLock);
return true;
}
// if the key doesn't exist, set *pInterface to null
// so that it is a valid XPCOM getter
if (pInterface)
*pInterface = nullptr;
PR_Unlock(this->mLock);
return false;
}
#endif // nsInterfaceHashtable_h__