gecko-dev/xpcom/glue/nsRefPtrHashtable.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is C++ hashtable templates.
*
* The Initial Developer of the Original Code is
* Benjamin Smedberg.
* Portions created by the Initial Developer are Copyright (C) 2002
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Neil Rashbrook <neil@parkwaycc.co.uk>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#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 RefPtr the reference-type being wrapped
* @see nsDataHashtable, nsClassHashtable
*/
template<class KeyClass, class RefPtr>
class nsRefPtrHashtable :
public nsBaseHashtable< KeyClass, nsRefPtr<RefPtr> , RefPtr* >
{
public:
typedef typename KeyClass::KeyType KeyType;
typedef RefPtr* UserDataType;
typedef nsBaseHashtable< KeyClass, nsRefPtr<RefPtr> , RefPtr* > 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 nsnull.
*/
PRBool Get(KeyType aKey, UserDataType* pData) const;
/**
* Gets a weak reference to the hashtable entry.
* @param aFound If not nsnull, will be set to PR_TRUE if the entry is found,
* to PR_FALSE otherwise.
* @return The entry, or nsnull if not found. Do not release this pointer!
*/
RefPtr* GetWeak(KeyType aKey, PRBool* aFound = nsnull) const;
};
/**
* Thread-safe version of nsRefPtrHashtable
* @param KeyClass a wrapper-class for the hashtable key, see nsHashKeys.h
* for a complete specification.
* @param RefPtr the reference-type being wrapped
*/
template<class KeyClass, class RefPtr>
class nsRefPtrHashtableMT :
public nsBaseHashtableMT< KeyClass, nsRefPtr<RefPtr> , RefPtr* >
{
public:
typedef typename KeyClass::KeyType KeyType;
typedef RefPtr* UserDataType;
typedef nsBaseHashtableMT< KeyClass, nsRefPtr<RefPtr> , RefPtr* > 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 nsnull.
*/
PRBool 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
};
//
// nsRefPtrHashtable definitions
//
template<class KeyClass, class RefPtr>
PRBool
nsRefPtrHashtable<KeyClass,RefPtr>::Get
(KeyType aKey, UserDataType* pRefPtr) const
{
typename base_type::EntryType* ent = this->GetEntry(aKey);
if (ent)
{
if (pRefPtr)
{
*pRefPtr = ent->mData;
NS_IF_ADDREF(*pRefPtr);
}
return PR_TRUE;
}
// if the key doesn't exist, set *pRefPtr to null
// so that it is a valid XPCOM getter
if (pRefPtr)
*pRefPtr = nsnull;
return PR_FALSE;
}
template<class KeyClass, class RefPtr>
RefPtr*
nsRefPtrHashtable<KeyClass,RefPtr>::GetWeak
(KeyType aKey, PRBool* aFound) const
{
typename base_type::EntryType* ent = this->GetEntry(aKey);
if (ent)
{
if (aFound)
*aFound = PR_TRUE;
return ent->mData;
}
// Key does not exist, return nsnull and set aFound to PR_FALSE
if (aFound)
*aFound = PR_FALSE;
return nsnull;
}
//
// nsRefPtrHashtableMT definitions
//
template<class KeyClass, class RefPtr>
PRBool
nsRefPtrHashtableMT<KeyClass,RefPtr>::Get
(KeyType aKey, UserDataType* pRefPtr) const
{
PR_Lock(this->mLock);
typename base_type::EntryType* ent = this->GetEntry(aKey);
if (ent)
{
if (pRefPtr)
{
*pRefPtr = ent->mData;
NS_IF_ADDREF(*pRefPtr);
}
PR_Unlock(this->mLock);
return PR_TRUE;
}
// if the key doesn't exist, set *pRefPtr to null
// so that it is a valid XPCOM getter
if (pRefPtr)
*pRefPtr = nsnull;
PR_Unlock(this->mLock);
return PR_FALSE;
}
#endif // nsRefPtrHashtable_h__