content/svg/content/src/nsSVGAttrTearoffTable.h
author David Anderson <danderson@mozilla.com>
Fri, 27 Jan 2012 15:49:15 -0800
changeset 112490 5f86dd728a3c9935f95b0e1a3cde2de68a346af3
parent 112135 f93960a93ad97a56d308bd9ce25d97cbc175d524
parent 88281 e31b47c574bff4c89cff38855b40a56865092388
child 113095 80e4ab0d24bc64ceaa7693ab5def36faffde7a40
permissions -rw-r--r--
Merge from mozilla-central.

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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 *
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 * 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 the Mozilla SVG project.
 *
 * Contributor(s):
 *   Brian Birtles <birtles@gmail.com>
 *
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 * 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"),
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#ifndef NS_SVGATTRTEAROFFTABLE_H_
#define NS_SVGATTRTEAROFFTABLE_H_

#include "nsDataHashtable.h"
#include "nsDebug.h"
#include "nsHashKeys.h"

/**
 * Global hashmap to associate internal SVG data types (e.g. nsSVGLength2) with
 * DOM tear-off objects (e.g. nsIDOMSVGLength). This allows us to always return
 * the same object for subsequent requests for DOM objects.
 *
 * We don't keep an owning reference to the tear-off objects so they are
 * responsible for removing themselves from this table when they die.
 */
template<class SimpleType, class TearoffType>
class nsSVGAttrTearoffTable
{
public:
  ~nsSVGAttrTearoffTable()
  {
    NS_ABORT_IF_FALSE(mTable.Count() == 0,
        "Tear-off objects remain in hashtable at shutdown.");
  }

  TearoffType* GetTearoff(SimpleType* aSimple);

  void AddTearoff(SimpleType* aSimple, TearoffType* aTearoff);

  void RemoveTearoff(SimpleType* aSimple);

private:
  typedef nsPtrHashKey<SimpleType> SimpleTypePtrKey;
  typedef nsDataHashtable<SimpleTypePtrKey, TearoffType* > TearoffTable;

  TearoffTable mTable;
};

template<class SimpleType, class TearoffType>
TearoffType*
nsSVGAttrTearoffTable<SimpleType, TearoffType>::GetTearoff(SimpleType* aSimple)
{
  if (!mTable.IsInitialized())
    return nsnull;

  TearoffType *tearoff = nsnull;

#ifdef DEBUG
  bool found =
#endif
    mTable.Get(aSimple, &tearoff);
  NS_ABORT_IF_FALSE(!found || tearoff,
      "NULL pointer stored in attribute tear-off map");

  return tearoff;
}

template<class SimpleType, class TearoffType>
void
nsSVGAttrTearoffTable<SimpleType, TearoffType>::AddTearoff(SimpleType* aSimple,
                                                          TearoffType* aTearoff)
{
  if (!mTable.IsInitialized()) {
    mTable.Init();
  }

  // We shouldn't be adding a tear-off if there already is one. If that happens,
  // something is wrong.
  if (mTable.Get(aSimple, nsnull)) {
    NS_ABORT_IF_FALSE(false, "There is already a tear-off for this object.");
    return;
  }

#ifdef DEBUG
  bool result =
#endif
    mTable.Put(aSimple, aTearoff);
  NS_ABORT_IF_FALSE(result, "Out of memory.");
}

template<class SimpleType, class TearoffType>
void
nsSVGAttrTearoffTable<SimpleType, TearoffType>::RemoveTearoff(
    SimpleType* aSimple)
{
  if (!mTable.IsInitialized()) {
    // Perhaps something happened in between creating the SimpleType object and
    // registering it
    return;
  }

  mTable.Remove(aSimple);
}

#endif // NS_SVGATTRTEAROFFTABLE_H_