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       1             : /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
       2             : /* vim: set ts=8 sts=2 et sw=2 tw=80: */
       3             : /* This Source Code Form is subject to the terms of the Mozilla Public
       4             :  * License, v. 2.0. If a copy of the MPL was not distributed with this
       5             :  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
       6             : 
       7             : #ifndef NS_SVGATTRTEAROFFTABLE_H_
       8             : #define NS_SVGATTRTEAROFFTABLE_H_
       9             : 
      10             : #include "nsDataHashtable.h"
      11             : #include "nsDebug.h"
      12             : #include "nsHashKeys.h"
      13             : 
      14             : /**
      15             :  * Global hashmap to associate internal SVG data types (e.g. nsSVGLength2) with
      16             :  * DOM tear-off objects (e.g. nsIDOMSVGLength). This allows us to always return
      17             :  * the same object for subsequent requests for DOM objects.
      18             :  *
      19             :  * We don't keep an owning reference to the tear-off objects so they are
      20             :  * responsible for removing themselves from this table when they die.
      21             :  */
      22             : template<class SimpleType, class TearoffType>
      23             : class nsSVGAttrTearoffTable
      24             : {
      25             : public:
      26             : #ifdef DEBUG
      27           0 :   ~nsSVGAttrTearoffTable()
      28             :   {
      29           0 :     MOZ_ASSERT(!mTable, "Tear-off objects remain in hashtable at shutdown.");
      30           0 :   }
      31             : #endif
      32             : 
      33             :   TearoffType* GetTearoff(SimpleType* aSimple);
      34             : 
      35             :   void AddTearoff(SimpleType* aSimple, TearoffType* aTearoff);
      36             : 
      37             :   void RemoveTearoff(SimpleType* aSimple);
      38             : 
      39             : private:
      40             :   typedef nsPtrHashKey<SimpleType> SimpleTypePtrKey;
      41             :   typedef nsDataHashtable<SimpleTypePtrKey, TearoffType* > TearoffTable;
      42             : 
      43             :   TearoffTable* mTable;
      44             : };
      45             : 
      46             : template<class SimpleType, class TearoffType>
      47             : TearoffType*
      48         123 : nsSVGAttrTearoffTable<SimpleType, TearoffType>::GetTearoff(SimpleType* aSimple)
      49             : {
      50         123 :   if (!mTable)
      51         123 :     return nullptr;
      52             : 
      53           0 :   TearoffType *tearoff = nullptr;
      54             : 
      55             : #ifdef DEBUG
      56             :   bool found =
      57             : #endif
      58           0 :     mTable->Get(aSimple, &tearoff);
      59           0 :   MOZ_ASSERT(!found || tearoff,
      60             :              "null pointer stored in attribute tear-off map");
      61             : 
      62           0 :   return tearoff;
      63             : }
      64             : 
      65             : template<class SimpleType, class TearoffType>
      66             : void
      67           0 : nsSVGAttrTearoffTable<SimpleType, TearoffType>::AddTearoff(SimpleType* aSimple,
      68             :                                                           TearoffType* aTearoff)
      69             : {
      70           0 :   if (!mTable) {
      71           0 :     mTable = new TearoffTable;
      72             :   }
      73             : 
      74             :   // We shouldn't be adding a tear-off if there already is one. If that happens,
      75             :   // something is wrong.
      76           0 :   if (mTable->Get(aSimple, nullptr)) {
      77           0 :     MOZ_ASSERT(false, "There is already a tear-off for this object.");
      78             :     return;
      79             :   }
      80             : 
      81           0 :   mTable->Put(aSimple, aTearoff);
      82           0 : }
      83             : 
      84             : template<class SimpleType, class TearoffType>
      85             : void
      86           0 : nsSVGAttrTearoffTable<SimpleType, TearoffType>::RemoveTearoff(
      87             :     SimpleType* aSimple)
      88             : {
      89           0 :   if (!mTable) {
      90             :     // Perhaps something happened in between creating the SimpleType object and
      91             :     // registering it
      92           0 :     return;
      93             :   }
      94             : 
      95           0 :   mTable->Remove(aSimple);
      96           0 :   if (mTable->Count() == 0) {
      97           0 :     delete mTable;
      98           0 :     mTable = nullptr;
      99             :   }
     100             : }
     101             : 
     102             : #endif // NS_SVGATTRTEAROFFTABLE_H_