gecko-dev/xpcom/glue/nsBaseHashtable.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):
*
* 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 nsBaseHashtable_h__
#define nsBaseHashtable_h__
#include "nsTHashtable.h"
#include NEW_H
typedef struct PRRWLock PRRWLock;
template<class KeyClass,class DataType,class UserDataType>
class nsBaseHashtable; // forward declaration
/**
* the private nsTHashtable::EntryType class used by nsBaseHashtable
* @see nsTHashtable for the specification of this class
* @see nsBaseHashtable for template parameters
*/
template<class KeyClass,class DataType>
class nsBaseHashtableET : public KeyClass
{
public:
DataType mData;
friend class nsTHashtable< nsBaseHashtableET<KeyClass,DataType> >;
private:
typedef typename KeyClass::KeyType KeyType;
typedef typename KeyClass::KeyTypePointer KeyTypePointer;
nsBaseHashtableET(KeyTypePointer aKey);
nsBaseHashtableET(const nsBaseHashtableET<KeyClass,DataType>& toCopy);
~nsBaseHashtableET();
};
/**
* templated hashtable for simple data types
* This class manages simple data types that do not need construction or
* destruction. Thread-safety is optional, via a flag in Init()
*
* @param KeyClass a wrapper-class for the hashtable key, see nsHashKeys.h
* for a complete specification.
* @param DataType the datatype stored in the hashtable,
* for example, PRUint32 or nsCOMPtr. If UserDataType is not the same,
* DataType must implicitly cast to UserDataType
* @param UserDataType the user sees, for example PRUint32 or nsISupports*
*/
template<class KeyClass,class DataType,class UserDataType>
class nsBaseHashtable :
protected nsTHashtable< nsBaseHashtableET<KeyClass,DataType> >
{
public:
typedef typename KeyClass::KeyType KeyType;
typedef nsBaseHashtableET<KeyClass,DataType> EntryType;
/**
* The constructor does not initialize, you must call Init() after
* construction.
*/
nsBaseHashtable();
/**
* destructor finalizes and deallocates hashtable
*/
~nsBaseHashtable();
/**
* Initialize the object.
* @param initSize the initial number of buckets in the hashtable,
default 16
* @param threadSafe whether to provide read/write
* locking on all class methods
* @return PR_TRUE if the object was initialized properly.
*/
PRBool Init(PRUint32 initSize = PL_DHASH_MIN_SIZE,
PRBool threadSafe = PR_FALSE);
/**
* retrieve the value for a key.
* @param aKey the key to retreive
* @param pData data associated with this key will be placed at this
* pointer. If you only need to check if the key exists, pData
* may be null.
* @return PR_TRUE if the key exists. If key does not exist, pData is not
* modified.
*/
PRBool Get(KeyType aKey, UserDataType* pData) const;
/**
* put a new value for the associated key
* @param aKey the key to put
* @param aData the new data
* @return always PR_TRUE, unless memory allocation failed
*/
PRBool Put(KeyType aKey, UserDataType aData);
/**
* remove the data for the associated key
* @param aKey the key to remove from the hashtable
*/
void Remove(KeyType aKey);
/**
* function type provided by the application for enumeration.
* currently, only "read" enumeration is supported. If you need to change
* or remove entries during enumeration, it might could be arranged.
* @param aKey the key being enumerated
* @param aData data being enumerated
* @parm userArg passed unchanged from Enumerate
* @return either
* @link PLDHashOperator::PL_DHASH_NEXT PL_DHASH_NEXT @endlink or
* @link PLDHashOperator::PL_DHASH_STOP PL_DHASH_STOP @endlink
*/
typedef PLDHashOperator
(*PR_CALLBACK EnumReadFunction)(KeyType aKey,
DataType aData,
void* userArg);
/**
* enumerate entries in the hashtable, without allowing changes
* this function read-locks the hashtable, so other threads may read keys
* at the same time in multi-thread environments.
* @param enumFunc enumeration callback
* @param userArg passed unchanged to the EnumReadFunction
*/
void EnumerateRead(EnumReadFunction enumFunc, void* userArg) const;
/**
* reset the hashtable, removing all entries
*/
void Clear();
protected:
PRRWLock* mLock;
/**
* used internally during EnumerateRead. Allocated on the stack.
* @param func the enumerator passed to EnumerateRead
* @param userArg the userArg passed to EnumerateRead
*/
struct s_EnumReadArgs
{
EnumReadFunction func;
void* userArg;
};
static PLDHashOperator s_EnumReadStub(PLDHashTable *table,
PLDHashEntryHdr *hdr,
PRUint32 number,
void *arg);
};
#ifndef HAVE_CPP_EXTERN_INSTANTIATION
#include "nsBaseHashtableImpl.h"
#endif
#endif // nsBaseHashtable_h__