gecko-dev/xpcom/ds/nsInterfaceHashtable.h

/* -*- 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
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 * ***** END LICENSE BLOCK ***** */

#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;
  /**
   * @copydoc nsBaseHashtable::nsBaseHashtable
   */
  nsInterfaceHashtable() { }

  /**
   * destructor, cleans up properly
   */
  ~nsInterfaceHashtable() { }

  /**
   * @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;
};

/**
 * declare shared-linkage for common usages of nsDataHashtable.
 *
 * To avoid including this code in multiple translation units, common usages
 * are predeclared with external linkage.  To add to this list, include the
 * declarations here, definitions in nsTHashtable.cpp and dlldeps.cpp .  This
 * only works if the configure-test HAVE_CPP_EXTERN_INSTANTIATION succeeds.
 */
#ifndef HAVE_CPP_EXTERN_INSTANTIATION
  #include "nsInterfaceHashtableImpl.h"
#else
  #ifndef NO_THASHTABLE_EXTERN_DECL
    extern template class NS_COM nsBaseHashtableET<nsStringHashKey, nsCOMPtr<nsISupports> >;
    extern template class NS_COM nsTHashtable< nsBaseHashtableET<nsStringHashKey,nsCOMPtr<nsISupports> > >;
    extern template class NS_COM nsBaseHashtable<nsStringHashKey, nsCOMPtr<nsISupports>, nsISupports*>;
    extern template class NS_COM nsInterfaceHashtable<nsStringHashKey, nsISupports>;
  #else
    #include "nsInterfaceHashtableImpl.h"
  #endif
#endif

#endif // nsInterfaceHashtable_h__