gecko/accessible/src/base/nsAccCache.h

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
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 * The contents of this file are subject to the Mozilla Public License Version
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 *
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 * for the specific language governing rights and limitations under the
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 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
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 * Portions created by the Initial Developer are Copyright (C) 2010
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Alexander Surkov <surkov.alexander@gmail.com> (original author)
 *
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 * either of the GNU General Public License Version 2 or later (the "GPL"),
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#ifndef _nsAccCache_H_
#define _nsAccCache_H_

#include "nsRefPtrHashtable.h"
#include "nsCycleCollectionParticipant.h"

class nsAccessNode;
class nsAccessible;
class nsIAccessNode;

typedef nsRefPtrHashtable<nsVoidPtrHashKey, nsAccessNode>
  nsAccessNodeHashtable;

typedef nsRefPtrHashtable<nsVoidPtrHashKey, nsAccessible>
  nsAccessibleHashtable;

/**
 * Shutdown and removes the accessible from cache.
 */
template <class T>
static PLDHashOperator
ClearCacheEntry(const void* aKey, nsRefPtr<T>& aAccessNode, void* aUserArg)
{
  NS_ASSERTION(aAccessNode, "Calling ClearCacheEntry with a NULL pointer!");
  if (aAccessNode)
    aAccessNode->Shutdown();

  return PL_DHASH_REMOVE;
}

/**
 * Clear the cache and shutdown the accessibles.
 */
template <class T>
static void
ClearCache(nsRefPtrHashtable<nsVoidPtrHashKey, T> & aCache)
{
  aCache.Enumerate(ClearCacheEntry<T>, nsnull);
}

/**
 * Traverse the accessible cache entry for cycle collector.
 */
template <class T>
static PLDHashOperator
CycleCollectorTraverseCacheEntry(const void *aKey, T *aAccessNode,
                                 void *aUserArg)
{
  nsCycleCollectionTraversalCallback *cb =
    static_cast<nsCycleCollectionTraversalCallback*>(aUserArg);

  NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(*cb, "accessible cache entry");

  nsISupports *supports = static_cast<nsIAccessNode*>(aAccessNode);
  cb->NoteXPCOMChild(supports);
  return PL_DHASH_NEXT;
}

/**
 * Traverse the accessible cache for cycle collector.
 */
template <class T>
static void
CycleCollectorTraverseCache(nsRefPtrHashtable<nsVoidPtrHashKey, T> & aCache,
                            nsCycleCollectionTraversalCallback *aCallback)
{
  aCache.EnumerateRead(CycleCollectorTraverseCacheEntry<T>, aCallback);
}

#endif