dom/svg/DOMSVGTransformList.h

   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 DOM_SVG_DOMSVGTRANSFORMLIST_H_
   8 #define DOM_SVG_DOMSVGTRANSFORMLIST_H_
   9
  10 #include "DOMSVGAnimatedTransformList.h"
  11 #include "mozAutoDocUpdate.h"
  12 #include "nsCycleCollectionParticipant.h"
  13 #include "nsDebug.h"
  14 #include "SVGTransformList.h"
  15 #include "nsTArray.h"
  16 #include "mozilla/Attributes.h"
  17
  18 namespace mozilla {
  19 class ErrorResult;
  20
  21 namespace dom {
  22 struct DOMMatrix2DInit;
  23 class DOMSVGTransform;
  24 class SVGElement;
  25 class SVGMatrix;
  26
  27 //----------------------------------------------------------------------
  28 // Helper class: AutoChangeTransformListNotifier
  29 // Stack-based helper class to pair calls to WillChangeTransformList and
  30 // DidChangeTransformList. Used by DOMSVGTransform and DOMSVGTransformList.
  31 template <class T>
  32 class MOZ_RAII AutoChangeTransformListNotifier {
  33  public:
  34   explicit AutoChangeTransformListNotifier(T* aValue) : mValue(aValue) {
  35     MOZ_ASSERT(mValue, "Expecting non-null value");
  36     // If we don't have an owner then changes don't affect anything else.
  37     if (mValue->HasOwner()) {
  38       mUpdateBatch.emplace(mValue->Element()->GetComposedDoc(), true);
  39       mEmptyOrOldValue =
  40           mValue->Element()->WillChangeTransformList(mUpdateBatch.ref());
  41     }
  42   }
  43
  44   ~AutoChangeTransformListNotifier() {
  45     if (mValue->HasOwner()) {
  46       mValue->Element()->DidChangeTransformList(mEmptyOrOldValue,
  47                                                 mUpdateBatch.ref());
  48       if (mValue->IsAnimating()) {
  49         mValue->Element()->AnimationNeedsResample();
  50       }
  51     }
  52   }
  53
  54  private:
  55   T* const mValue;
  56   Maybe<mozAutoDocUpdate> mUpdateBatch;
  57   nsAttrValue mEmptyOrOldValue;
  58 };
  59
  60 /**
  61  * Class DOMSVGTransformList
  62  *
  63  * This class is used to create the DOM tearoff objects that wrap internal
  64  * SVGTransformList objects.
  65  *
  66  * See the architecture comment in DOMSVGAnimatedTransformList.h.
  67  */
  68 class DOMSVGTransformList final : public nsISupports, public nsWrapperCache {
  69   template <class T>
  70   friend class AutoChangeTransformListNotifier;
  71   friend class dom::DOMSVGTransform;
  72
  73   ~DOMSVGTransformList() {
  74     // Our mAList's weak ref to us must be nulled out when we die. If GC has
  75     // unlinked us using the cycle collector code, then that has already
  76     // happened, and mAList is null.
  77     if (mAList) {
  78       (IsAnimValList() ? mAList->mAnimVal : mAList->mBaseVal) = nullptr;
  79     }
  80   }
  81
  82  public:
  83   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  84   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(DOMSVGTransformList)
  85
  86   DOMSVGTransformList(dom::DOMSVGAnimatedTransformList* aAList,
  87                       const SVGTransformList& aInternalList)
  88       : mAList(aAList) {
  89     // aInternalList must be passed in explicitly because we can't use
  90     // InternalList() here. (Because it depends on IsAnimValList, which depends
  91     // on this object having been assigned to aAList's mBaseVal or mAnimVal,
  92     // which hasn't happened yet.)
  93
  94     InternalListLengthWillChange(aInternalList.Length());  // Sync mItems
  95   }
  96
  97   virtual JSObject* WrapObject(JSContext* cx,
  98                                JS::Handle<JSObject*> aGivenProto) override;
  99
 100   nsISupports* GetParentObject() { return static_cast<nsIContent*>(Element()); }
 101
 102   /**
 103    * This will normally be the same as InternalList().Length(), except if we've
 104    * hit OOM in which case our length will be zero.
 105    */
 106   uint32_t LengthNoFlush() const {
 107     MOZ_ASSERT(mItems.IsEmpty() || mItems.Length() == InternalList().Length(),
 108                "DOM wrapper's list length is out of sync");
 109     return mItems.Length();
 110   }
 111
 112   /// Called to notify us to synchronize our length and detach excess items.
 113   void InternalListLengthWillChange(uint32_t aNewLength);
 114
 115   /*
 116    * List classes always have an owner. We need this so that templates that work
 117    * on lists and elements can check ownership where elements may be unowned.
 118    */
 119   bool HasOwner() const { return true; }
 120
 121   /**
 122    * Returns true if our attribute is animating (in which case our animVal is
 123    * not simply a mirror of our baseVal).
 124    */
 125   bool IsAnimating() const { return mAList->IsAnimating(); }
 126   /**
 127    * Returns true if there is an animated list mirroring the base list.
 128    */
 129   bool AnimListMirrorsBaseList() const {
 130     return mAList->mAnimVal && !mAList->IsAnimating();
 131   }
 132
 133   uint32_t NumberOfItems() const {
 134     if (IsAnimValList()) {
 135       Element()->FlushAnimations();
 136     }
 137     return LengthNoFlush();
 138   }
 139   void Clear(ErrorResult& error);
 140   already_AddRefed<dom::DOMSVGTransform> Initialize(
 141       dom::DOMSVGTransform& newItem, ErrorResult& error);
 142   already_AddRefed<dom::DOMSVGTransform> GetItem(uint32_t index,
 143                                                  ErrorResult& error);
 144   already_AddRefed<dom::DOMSVGTransform> IndexedGetter(uint32_t index,
 145                                                        bool& found,
 146                                                        ErrorResult& error);
 147   already_AddRefed<dom::DOMSVGTransform> InsertItemBefore(
 148       dom::DOMSVGTransform& newItem, uint32_t index, ErrorResult& error);
 149   already_AddRefed<dom::DOMSVGTransform> ReplaceItem(
 150       dom::DOMSVGTransform& newItem, uint32_t index, ErrorResult& error);
 151   already_AddRefed<dom::DOMSVGTransform> RemoveItem(uint32_t index,
 152                                                     ErrorResult& error);
 153   already_AddRefed<dom::DOMSVGTransform> AppendItem(
 154       dom::DOMSVGTransform& newItem, ErrorResult& error) {
 155     return InsertItemBefore(newItem, LengthNoFlush(), error);
 156   }
 157   already_AddRefed<dom::DOMSVGTransform> CreateSVGTransformFromMatrix(
 158       const DOMMatrix2DInit& aMatrix, ErrorResult& aRv);
 159   already_AddRefed<dom::DOMSVGTransform> Consolidate(ErrorResult& error);
 160   uint32_t Length() const { return NumberOfItems(); }
 161
 162  private:
 163   dom::SVGElement* Element() const { return mAList->mElement; }
 164
 165   /// Used to determine if this list is the baseVal or animVal list.
 166   bool IsAnimValList() const {
 167     MOZ_ASSERT(this == mAList->mBaseVal || this == mAList->mAnimVal,
 168                "Calling IsAnimValList() too early?!");
 169     return this == mAList->mAnimVal;
 170   }
 171
 172   /**
 173    * Get a reference to this object's corresponding internal SVGTransformList.
 174    *
 175    * To simplify the code we just have this one method for obtaining both
 176    * baseVal and animVal internal lists. This means that animVal lists don't
 177    * get const protection, but our setter methods guard against changing
 178    * animVal lists.
 179    */
 180   SVGTransformList& InternalList() const;
 181
 182   /// Returns the DOMSVGTransform at aIndex, creating it if necessary.
 183   already_AddRefed<dom::DOMSVGTransform> GetItemAt(uint32_t aIndex);
 184
 185   void MaybeInsertNullInAnimValListAt(uint32_t aIndex);
 186   void MaybeRemoveItemFromAnimValListAt(uint32_t aIndex);
 187
 188   // Weak refs to our DOMSVGTransform items. The items are friends and take care
 189   // of clearing our pointer to them when they die.
 190   FallibleTArray<dom::DOMSVGTransform*> mItems;
 191
 192   RefPtr<dom::DOMSVGAnimatedTransformList> mAList;
 193 };
 194
 195 }  // namespace dom
 196 }  // namespace mozilla
 197
 198 #endif  // DOM_SVG_DOMSVGTRANSFORMLIST_H_