tor-browser

DOMSVGNumberList.h (6940B)

---

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef DOM_SVG_DOMSVGNUMBERLIST_H_
#define DOM_SVG_DOMSVGNUMBERLIST_H_

#include "DOMSVGAnimatedNumberList.h"
#include "SVGNumberList.h"
#include "mozAutoDocUpdate.h"
#include "mozilla/Attributes.h"
#include "mozilla/RefPtr.h"
#include "nsCycleCollectionParticipant.h"
#include "nsDebug.h"
#include "nsTArray.h"

namespace mozilla {
class ErrorResult;

namespace dom {
class DOMSVGNumber;
class SVGElement;

//----------------------------------------------------------------------
// Helper class: AutoChangeNumberListNotifier
// Stack-based helper class to pair calls to WillChangeNumberList and
// DidChangeNumberList. Used by DOMSVGNumber and DOMSVGNumberList.
template <class T>
class MOZ_RAII AutoChangeNumberListNotifier : public mozAutoDocUpdate {
public:
 explicit AutoChangeNumberListNotifier(T* aValue)
     : mozAutoDocUpdate(aValue->Element()->GetComposedDoc(), true),
       mValue(aValue) {
   MOZ_ASSERT(mValue, "Expecting non-null value");
   mValue->Element()->WillChangeNumberList(mValue->AttrEnum(), *this);
 }

 ~AutoChangeNumberListNotifier() {
   mValue->Element()->DidChangeNumberList(mValue->AttrEnum(), *this);
   if (mValue->IsAnimating()) {
     mValue->Element()->AnimationNeedsResample();
   }
 }

private:
 T* const mValue;
};

/**
* Class DOMSVGNumberList
*
* This class is used to create the DOM tearoff objects that wrap internal
* SVGNumberList objects.
*
* See the architecture comment in DOMSVGAnimatedNumberList.h.
*
* This class is strongly intertwined with DOMSVGAnimatedNumberList and
* DOMSVGNumber. We are a friend of DOMSVGAnimatedNumberList, and are
* responsible for nulling out our DOMSVGAnimatedNumberList's pointer to us
* when we die, essentially making its pointer to us a weak pointer. Similarly,
* our DOMSVGNumber items are friends of us and responsible for nulling out our
* pointers to them.
*
* Our DOM items are created lazily on demand as and when script requests them.
*/
class DOMSVGNumberList final : public nsISupports, public nsWrapperCache {
 template <class T>
 friend class AutoChangeNumberListNotifier;
 friend class DOMSVGNumber;

 ~DOMSVGNumberList() {
   // Our mAList's weak ref to us must be nulled out when we die. If GC has
   // unlinked us using the cycle collector code, then that has already
   // happened, and mAList is null.
   if (mAList) {
     (IsAnimValList() ? mAList->mAnimVal : mAList->mBaseVal) = nullptr;
   }
 }

public:
 NS_DECL_CYCLE_COLLECTING_ISUPPORTS
 NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(DOMSVGNumberList)

 DOMSVGNumberList(DOMSVGAnimatedNumberList* aAList,
                  const SVGNumberList& aInternalList)
     : mAList(aAList) {
   // aInternalList must be passed in explicitly because we can't use
   // InternalList() here. (Because it depends on IsAnimValList, which depends
   // on this object having been assigned to aAList's mBaseVal or mAnimVal,
   // which hasn't happened yet.)

   InternalListLengthWillChange(aInternalList.Length());  // Sync mItems
 }

 JSObject* WrapObject(JSContext* cx,
                      JS::Handle<JSObject*> aGivenProto) override;

 nsISupports* GetParentObject() { return static_cast<nsIContent*>(Element()); }

 /**
  * This will normally be the same as InternalList().Length(), except if we've
  * hit OOM in which case our length will be zero.
  */
 uint32_t LengthNoFlush() const {
   MOZ_ASSERT(
       mItems.Length() == 0 || mItems.Length() == InternalList().Length(),
       "DOM wrapper's list length is out of sync");
   return mItems.Length();
 }

 /// Called to notify us to synchronize our length and detach excess items.
 void InternalListLengthWillChange(uint32_t aNewLength);

 /**
  * Returns true if our attribute is animating (in which case our animVal is
  * not simply a mirror of our baseVal).
  */
 bool IsAnimating() const { return mAList->IsAnimating(); }
 /**
  * Returns true if there is an animated list mirroring the base list.
  */
 bool AnimListMirrorsBaseList() const {
   return mAList->mAnimVal && !mAList->IsAnimating();
 }

 uint32_t NumberOfItems() const {
   if (IsAnimValList()) {
     Element()->FlushAnimations();
   }
   return LengthNoFlush();
 }
 void Clear(ErrorResult& aRv);
 already_AddRefed<DOMSVGNumber> Initialize(DOMSVGNumber& aItem,
                                           ErrorResult& aRv);
 already_AddRefed<DOMSVGNumber> GetItem(uint32_t index, ErrorResult& aRv);
 already_AddRefed<DOMSVGNumber> IndexedGetter(uint32_t index, bool& found,
                                              ErrorResult& aRv);
 already_AddRefed<DOMSVGNumber> InsertItemBefore(DOMSVGNumber& aItem,
                                                 uint32_t index,
                                                 ErrorResult& aRv);
 already_AddRefed<DOMSVGNumber> ReplaceItem(DOMSVGNumber& aItem,
                                            uint32_t index, ErrorResult& aRv);
 already_AddRefed<DOMSVGNumber> RemoveItem(uint32_t index, ErrorResult& aRv);
 already_AddRefed<DOMSVGNumber> AppendItem(DOMSVGNumber& newItem,
                                           ErrorResult& aRv) {
   return InsertItemBefore(newItem, LengthNoFlush(), aRv);
 }
 uint32_t Length() const { return NumberOfItems(); }

private:
 dom::SVGElement* Element() const { return mAList->mElement; }

 uint8_t AttrEnum() const { return mAList->mAttrEnum; }

 /// Used to determine if this list is the baseVal or animVal list.
 bool IsAnimValList() const {
   MOZ_ASSERT(this == mAList->mBaseVal || this == mAList->mAnimVal,
              "Calling IsAnimValList() too early?!");
   return this == mAList->mAnimVal;
 }

 /**
  * Get a reference to this object's corresponding internal SVGNumberList.
  *
  * To simplify the code we just have this one method for obtaining both
  * baseVal and animVal internal lists. This means that animVal lists don't
  * get const protection, but our setter methods guard against changing
  * animVal lists.
  */
 SVGNumberList& InternalList() const;

 /// Returns the DOMSVGNumber at aIndex, creating it if necessary.
 already_AddRefed<DOMSVGNumber> GetItemAt(uint32_t aIndex);

 void MaybeInsertNullInAnimValListAt(uint32_t aIndex);
 void MaybeRemoveItemFromAnimValListAt(uint32_t aIndex);

 // Weak refs to our DOMSVGNumber items. The items are friends and take care
 // of clearing our pointer to them when they die.
 FallibleTArray<DOMSVGNumber*> mItems;

 RefPtr<DOMSVGAnimatedNumberList> mAList;
};

}  // namespace dom
}  // namespace mozilla

#endif  // DOM_SVG_DOMSVGNUMBERLIST_H_