dom/svg/SVGAnimatedLengthList.cpp

   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 #include "SVGAnimatedLengthList.h"
   8
   9 #include <utility>
  10
  11 #include "DOMSVGAnimatedLengthList.h"
  12 #include "SVGLengthListSMILType.h"
  13 #include "mozilla/SMILValue.h"
  14 #include "mozilla/dom/SVGElement.h"
  15 #include "mozilla/dom/SVGLengthBinding.h"
  16
  17 namespace mozilla {
  18
  19 using namespace dom;
  20
  21 nsresult SVGAnimatedLengthList::SetBaseValueString(const nsAString& aValue) {
  22   SVGLengthList newBaseValue;
  23   MOZ_TRY(newBaseValue.SetValueFromString(aValue));
  24
  25   DOMSVGAnimatedLengthList* domWrapper =
  26       DOMSVGAnimatedLengthList::GetDOMWrapperIfExists(this);
  27   if (domWrapper) {
  28     // We must send this notification *before* changing mBaseVal! If the length
  29     // of our baseVal is being reduced, our baseVal's DOM wrapper list may have
  30     // to remove DOM items from itself, and any removed DOM items need to copy
  31     // their internal counterpart values *before* we change them.
  32     //
  33     domWrapper->InternalBaseValListWillChangeTo(newBaseValue);
  34   }
  35
  36   // We don't need to call DidChange* here - we're only called by
  37   // SVGElement::ParseAttribute under Element::SetAttr,
  38   // which takes care of notifying.
  39   mBaseVal.SwapWith(newBaseValue);
  40   return NS_OK;
  41 }
  42
  43 void SVGAnimatedLengthList::ClearBaseValue(uint32_t aAttrEnum) {
  44   DOMSVGAnimatedLengthList* domWrapper =
  45       DOMSVGAnimatedLengthList::GetDOMWrapperIfExists(this);
  46   if (domWrapper) {
  47     // We must send this notification *before* changing mBaseVal! (See above.)
  48     domWrapper->InternalBaseValListWillChangeTo(SVGLengthList());
  49   }
  50   mBaseVal.Clear();
  51   // Caller notifies
  52 }
  53
  54 nsresult SVGAnimatedLengthList::SetAnimValue(const SVGLengthList& aNewAnimValue,
  55                                              SVGElement* aElement,
  56                                              uint32_t aAttrEnum) {
  57   DOMSVGAnimatedLengthList* domWrapper =
  58       DOMSVGAnimatedLengthList::GetDOMWrapperIfExists(this);
  59   if (domWrapper) {
  60     // A new animation may totally change the number of items in the animVal
  61     // list, replacing what was essentially a mirror of the baseVal list, or
  62     // else replacing and overriding an existing animation. When this happens
  63     // we must try and keep our animVal's DOM wrapper in sync (see the comment
  64     // in DOMSVGAnimatedLengthList::InternalBaseValListWillChangeTo).
  65     //
  66     // It's not possible for us to reliably distinguish between calls to this
  67     // method that are setting a new sample for an existing animation, and
  68     // calls that are setting the first sample of an animation that will
  69     // override an existing animation. Happily it's cheap to just blindly
  70     // notify our animVal's DOM wrapper of its internal counterpart's new value
  71     // each time this method is called, so that's what we do.
  72     //
  73     // Note that we must send this notification *before* setting or changing
  74     // mAnimVal! (See the comment in SetBaseValueString above.)
  75     //
  76     domWrapper->InternalAnimValListWillChangeTo(aNewAnimValue);
  77   }
  78   if (!mAnimVal) {
  79     mAnimVal = MakeUnique<SVGLengthList>();
  80   }
  81   nsresult rv = mAnimVal->CopyFrom(aNewAnimValue);
  82   if (NS_FAILED(rv)) {
  83     // OOM. We clear the animation, and, importantly, ClearAnimValue() ensures
  84     // that mAnimVal and its DOM wrapper (if any) will have the same length!
  85     ClearAnimValue(aElement, aAttrEnum);
  86     return rv;
  87   }
  88   aElement->DidAnimateLengthList(aAttrEnum);
  89   return NS_OK;
  90 }
  91
  92 void SVGAnimatedLengthList::ClearAnimValue(SVGElement* aElement,
  93                                            uint32_t aAttrEnum) {
  94   DOMSVGAnimatedLengthList* domWrapper =
  95       DOMSVGAnimatedLengthList::GetDOMWrapperIfExists(this);
  96   if (domWrapper) {
  97     // When all animation ends, animVal simply mirrors baseVal, which may have
  98     // a different number of items to the last active animated value. We must
  99     // keep the length of our animVal's DOM wrapper list in sync, and again we
 100     // must do that before touching mAnimVal. See comments above.
 101     //
 102     domWrapper->InternalAnimValListWillChangeTo(mBaseVal);
 103   }
 104   mAnimVal = nullptr;
 105   aElement->DidAnimateLengthList(aAttrEnum);
 106 }
 107
 108 UniquePtr<SMILAttr> SVGAnimatedLengthList::ToSMILAttr(SVGElement* aSVGElement,
 109                                                       uint8_t aAttrEnum,
 110                                                       uint8_t aAxis,
 111                                                       bool aCanZeroPadList) {
 112   return MakeUnique<SMILAnimatedLengthList>(this, aSVGElement, aAttrEnum, aAxis,
 113                                             aCanZeroPadList);
 114 }
 115
 116 nsresult SVGAnimatedLengthList::SMILAnimatedLengthList::ValueFromString(
 117     const nsAString& aStr, const dom::SVGAnimationElement* /*aSrcElement*/,
 118     SMILValue& aValue, bool& aPreventCachingOfSandwich) const {
 119   SMILValue val(&SVGLengthListSMILType::sSingleton);
 120   SVGLengthListAndInfo* llai = static_cast<SVGLengthListAndInfo*>(val.mU.mPtr);
 121   nsresult rv = llai->SetValueFromString(aStr);
 122   if (NS_SUCCEEDED(rv)) {
 123     llai->SetInfo(mElement, mAxis, mCanZeroPadList);
 124     aValue = std::move(val);
 125
 126     // If any of the lengths in the list depend on their context, then we must
 127     // prevent caching of the entire animation sandwich. This is because the
 128     // units of a length at a given index can change from sandwich layer to
 129     // layer, and indeed even be different within a single sandwich layer. If
 130     // any length in the result of an animation sandwich is the result of the
 131     // addition of lengths where one or more of those lengths is context
 132     // dependent, then naturally the resultant length is also context
 133     // dependent, regardless of whether its actual unit is context dependent or
 134     // not. Unfortunately normal invalidation mechanisms won't cause us to
 135     // recalculate the result of the sandwich if the context changes, so we
 136     // take the (substantial) performance hit of preventing caching of the
 137     // sandwich layer, causing the animation sandwich to be recalculated every
 138     // single sample.
 139
 140     for (uint32_t i = 0; i < llai->Length(); ++i) {
 141       uint8_t unit = (*llai)[i].GetUnit();
 142       if (!SVGLength::IsAbsoluteUnit(unit)) {
 143         aPreventCachingOfSandwich = true;
 144         break;
 145       }
 146     }
 147   }
 148   return rv;
 149 }
 150
 151 SMILValue SVGAnimatedLengthList::SMILAnimatedLengthList::GetBaseValue() const {
 152   // To benefit from Return Value Optimization and avoid copy constructor calls
 153   // due to our use of return-by-value, we must return the exact same object
 154   // from ALL return points. This function must only return THIS variable:
 155   SMILValue val;
 156
 157   SMILValue tmp(&SVGLengthListSMILType::sSingleton);
 158   SVGLengthListAndInfo* llai = static_cast<SVGLengthListAndInfo*>(tmp.mU.mPtr);
 159   nsresult rv = llai->CopyFrom(mVal->mBaseVal);
 160   if (NS_SUCCEEDED(rv)) {
 161     llai->SetInfo(mElement, mAxis, mCanZeroPadList);
 162     val = std::move(tmp);
 163   }
 164   return val;
 165 }
 166
 167 nsresult SVGAnimatedLengthList::SMILAnimatedLengthList::SetAnimValue(
 168     const SMILValue& aValue) {
 169   NS_ASSERTION(aValue.mType == &SVGLengthListSMILType::sSingleton,
 170                "Unexpected type to assign animated value");
 171   if (aValue.mType == &SVGLengthListSMILType::sSingleton) {
 172     mVal->SetAnimValue(*static_cast<SVGLengthListAndInfo*>(aValue.mU.mPtr),
 173                        mElement, mAttrEnum);
 174   }
 175   return NS_OK;
 176 }
 177
 178 void SVGAnimatedLengthList::SMILAnimatedLengthList::ClearAnimValue() {
 179   if (mVal->mAnimVal) {
 180     mVal->ClearAnimValue(mElement, mAttrEnum);
 181   }
 182 }
 183
 184 }  // namespace mozilla