dom/svg/DOMSVGLengthList.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef MOZILLA_DOMSVGLENGTHLIST_H__
   7 #define MOZILLA_DOMSVGLENGTHLIST_H__
   8
   9 #include "DOMSVGAnimatedLengthList.h"
  10 #include "nsAutoPtr.h"
  11 #include "nsCycleCollectionParticipant.h"
  12 #include "nsDebug.h"
  13 #include "nsTArray.h"
  14 #include "SVGLengthList.h"
  15 #include "mozilla/Attributes.h"
  16 #include "mozilla/ErrorResult.h"
  17
  18 class nsSVGElement;
  19
  20 namespace mozilla {
  21
  22 class DOMSVGLength;
  23
  24 /**
  25  * Class DOMSVGLengthList
  26  *
  27  * This class is used to create the DOM tearoff objects that wrap internal
  28  * SVGLengthList objects.
  29  *
  30  * See the architecture comment in DOMSVGAnimatedLengthList.h.
  31  *
  32  * This class is strongly intertwined with DOMSVGAnimatedLengthList and
  33  * DOMSVGLength. We are a friend of DOMSVGAnimatedLengthList, and are
  34  * responsible for nulling out our DOMSVGAnimatedLengthList's pointer to us
  35  * when we die, essentially making its pointer to us a weak pointer. Similarly,
  36  * our DOMSVGLength items are friends of us and responsible for nulling out our
  37  * pointers to them.
  38  *
  39  * Our DOM items are created lazily on demand as and when script requests them.
  40  */
  41 class DOMSVGLengthList MOZ_FINAL : public nsISupports,
  42                                    public nsWrapperCache
  43 {
  44   friend class AutoChangeLengthListNotifier;
  45   friend class DOMSVGLength;
  46
  47   ~DOMSVGLengthList() {
  48     // Our mAList's weak ref to us must be nulled out when we die. If GC has
  49     // unlinked us using the cycle collector code, then that has already
  50     // happened, and mAList is null.
  51     if (mAList) {
  52       ( IsAnimValList() ? mAList->mAnimVal : mAList->mBaseVal ) = nullptr;
  53     }
  54   }
  55
  56 public:
  57   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  58   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(DOMSVGLengthList)
  59
  60   DOMSVGLengthList(DOMSVGAnimatedLengthList *aAList,
  61                    const SVGLengthList &aInternalList)
  62     : mAList(aAList)
  63   {
  64     // aInternalList must be passed in explicitly because we can't use
  65     // InternalList() here. (Because it depends on IsAnimValList, which depends
  66     // on this object having been assigned to aAList's mBaseVal or mAnimVal,
  67     // which hasn't happend yet.)
  68
  69     InternalListLengthWillChange(aInternalList.Length()); // Sync mItems
  70   }
  71
  72   virtual JSObject* WrapObject(JSContext *cx) MOZ_OVERRIDE;
  73
  74   nsISupports* GetParentObject()
  75   {
  76     return static_cast<nsIContent*>(Element());
  77   }
  78
  79   /**
  80    * This will normally be the same as InternalList().Length(), except if we've
  81    * hit OOM in which case our length will be zero.
  82    */
  83   uint32_t LengthNoFlush() const {
  84     NS_ABORT_IF_FALSE(mItems.Length() == 0 ||
  85                       mItems.Length() == InternalList().Length(),
  86                       "DOM wrapper's list length is out of sync");
  87     return mItems.Length();
  88   }
  89
  90   /// Called to notify us to syncronize our length and detach excess items.
  91   void InternalListLengthWillChange(uint32_t aNewLength);
  92
  93   /**
  94    * Returns true if our attribute is animating (in which case our animVal is
  95    * not simply a mirror of our baseVal).
  96    */
  97   bool IsAnimating() const {
  98     return mAList->IsAnimating();
  99   }
 100
 101   uint32_t NumberOfItems() const
 102   {
 103     if (IsAnimValList()) {
 104       Element()->FlushAnimations();
 105     }
 106     return LengthNoFlush();
 107   }
 108   void Clear(ErrorResult& aError);
 109   already_AddRefed<DOMSVGLength> Initialize(DOMSVGLength& newItem,
 110                                             ErrorResult& error);
 111   already_AddRefed<DOMSVGLength> GetItem(uint32_t index,
 112                                          ErrorResult& error);
 113   already_AddRefed<DOMSVGLength> IndexedGetter(uint32_t index, bool& found,
 114                                                ErrorResult& error);
 115   already_AddRefed<DOMSVGLength> InsertItemBefore(DOMSVGLength& newItem,
 116                                                   uint32_t index,
 117                                                   ErrorResult& error);
 118   already_AddRefed<DOMSVGLength> ReplaceItem(DOMSVGLength& newItem,
 119                                              uint32_t index,
 120                                              ErrorResult& error);
 121   already_AddRefed<DOMSVGLength> RemoveItem(uint32_t index,
 122                                             ErrorResult& error);
 123   already_AddRefed<DOMSVGLength> AppendItem(DOMSVGLength& newItem,
 124                                             ErrorResult& error)
 125   {
 126     return InsertItemBefore(newItem, LengthNoFlush(), error);
 127   }
 128   uint32_t Length() const
 129   {
 130     return NumberOfItems();
 131   }
 132
 133 private:
 134
 135   nsSVGElement* Element() const {
 136     return mAList->mElement;
 137   }
 138
 139   uint8_t AttrEnum() const {
 140     return mAList->mAttrEnum;
 141   }
 142
 143   uint8_t Axis() const {
 144     return mAList->mAxis;
 145   }
 146
 147   /// Used to determine if this list is the baseVal or animVal list.
 148   bool IsAnimValList() const {
 149     NS_ABORT_IF_FALSE(this == mAList->mBaseVal || this == mAList->mAnimVal,
 150                       "Calling IsAnimValList() too early?!");
 151     return this == mAList->mAnimVal;
 152   }
 153
 154   /**
 155    * Get a reference to this object's corresponding internal SVGLengthList.
 156    *
 157    * To simplify the code we just have this one method for obtaining both
 158    * baseVal and animVal internal lists. This means that animVal lists don't
 159    * get const protection, but our setter methods guard against changing
 160    * animVal lists.
 161    */
 162   SVGLengthList& InternalList() const;
 163
 164   /// Returns the DOMSVGLength at aIndex, creating it if necessary.
 165   already_AddRefed<DOMSVGLength> GetItemAt(uint32_t aIndex);
 166
 167   void MaybeInsertNullInAnimValListAt(uint32_t aIndex);
 168   void MaybeRemoveItemFromAnimValListAt(uint32_t aIndex);
 169
 170   // Weak refs to our DOMSVGLength items. The items are friends and take care
 171   // of clearing our pointer to them when they die.
 172   FallibleTArray<DOMSVGLength*> mItems;
 173
 174   nsRefPtr<DOMSVGAnimatedLengthList> mAList;
 175 };
 176
 177 } // namespace mozilla
 178
 179 #endif // MOZILLA_DOMSVGLENGTHLIST_H__