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   nsresult rv = newBaseValue.SetValueFromString(aValue);
  24   if (NS_FAILED(rv)) {
  25     return rv;
  26   }
  27
  28   DOMSVGAnimatedLengthList* domWrapper =
  29       DOMSVGAnimatedLengthList::GetDOMWrapperIfExists(this);
  30   if (domWrapper) {
  31     // We must send this notification *before* changing mBaseVal! If the length
  32     // of our baseVal is being reduced, our baseVal's DOM wrapper list may have
  33     // to remove DOM items from itself, and any removed DOM items need to copy
  34     // their internal counterpart values *before* we change them.
  35     //
  36     domWrapper->InternalBaseValListWillChangeTo(newBaseValue);
  37   }
  38
  39   // We don't need to call DidChange* here - we're only called by
  40   // SVGElement::ParseAttribute under Element::SetAttr,
  41   // which takes care of notifying.
  42
  43   rv = mBaseVal.CopyFrom(newBaseValue);
  44   if (NS_FAILED(rv) && domWrapper) {
  45     // Attempting to increase mBaseVal's length failed - reduce domWrapper
  46     // back to the same length:
  47     domWrapper->InternalBaseValListWillChangeTo(mBaseVal);
  48   }
  49   return rv;
  50 }
  51
  52 void SVGAnimatedLengthList::ClearBaseValue(uint32_t aAttrEnum) {
  53   DOMSVGAnimatedLengthList* domWrapper =
  54       DOMSVGAnimatedLengthList::GetDOMWrapperIfExists(this);
  55   if (domWrapper) {
  56     // We must send this notification *before* changing mBaseVal! (See above.)
  57     domWrapper->InternalBaseValListWillChangeTo(SVGLengthList());
  58   }
  59   mBaseVal.Clear();
  60   // Caller notifies
  61 }
  62
  63 nsresult SVGAnimatedLengthList::SetAnimValue(const SVGLengthList& aNewAnimValue,
  64                                              SVGElement* aElement,
  65                                              uint32_t aAttrEnum) {
  66   DOMSVGAnimatedLengthList* domWrapper =
  67       DOMSVGAnimatedLengthList::GetDOMWrapperIfExists(this);
  68   if (domWrapper) {
  69     // A new animation may totally change the number of items in the animVal
  70     // list, replacing what was essentially a mirror of the baseVal list, or
  71     // else replacing and overriding an existing animation. When this happens
  72     // we must try and keep our animVal's DOM wrapper in sync (see the comment
  73     // in DOMSVGAnimatedLengthList::InternalBaseValListWillChangeTo).
  74     //
  75     // It's not possible for us to reliably distinguish between calls to this
  76     // method that are setting a new sample for an existing animation, and
  77     // calls that are setting the first sample of an animation that will
  78     // override an existing animation. Happily it's cheap to just blindly
  79     // notify our animVal's DOM wrapper of its internal counterpart's new value
  80     // each time this method is called, so that's what we do.
  81     //
  82     // Note that we must send this notification *before* setting or changing
  83     // mAnimVal! (See the comment in SetBaseValueString above.)
  84     //
  85     domWrapper->InternalAnimValListWillChangeTo(aNewAnimValue);
  86   }
  87   if (!mAnimVal) {
  88     mAnimVal = MakeUnique<SVGLengthList>();
  89   }
  90   nsresult rv = mAnimVal->CopyFrom(aNewAnimValue);
  91   if (NS_FAILED(rv)) {
  92     // OOM. We clear the animation, and, importantly, ClearAnimValue() ensures
  93     // that mAnimVal and its DOM wrapper (if any) will have the same length!
  94     ClearAnimValue(aElement, aAttrEnum);
  95     return rv;
  96   }
  97   aElement->DidAnimateLengthList(aAttrEnum);
  98   return NS_OK;
  99 }
 100
 101 void SVGAnimatedLengthList::ClearAnimValue(SVGElement* aElement,
 102                                            uint32_t aAttrEnum) {
 103   DOMSVGAnimatedLengthList* domWrapper =
 104       DOMSVGAnimatedLengthList::GetDOMWrapperIfExists(this);
 105   if (domWrapper) {
 106     // When all animation ends, animVal simply mirrors baseVal, which may have
 107     // a different number of items to the last active animated value. We must
 108     // keep the length of our animVal's DOM wrapper list in sync, and again we
 109     // must do that before touching mAnimVal. See comments above.
 110     //
 111     domWrapper->InternalAnimValListWillChangeTo(mBaseVal);
 112   }
 113   mAnimVal = nullptr;
 114   aElement->DidAnimateLengthList(aAttrEnum);
 115 }
 116
 117 UniquePtr<SMILAttr> SVGAnimatedLengthList::ToSMILAttr(SVGElement* aSVGElement,
 118                                                       uint8_t aAttrEnum,
 119                                                       uint8_t aAxis,
 120                                                       bool aCanZeroPadList) {
 121   return MakeUnique<SMILAnimatedLengthList>(this, aSVGElement, aAttrEnum, aAxis,
 122                                             aCanZeroPadList);
 123 }
 124
 125 nsresult SVGAnimatedLengthList::SMILAnimatedLengthList::ValueFromString(
 126     const nsAString& aStr, const dom::SVGAnimationElement* /*aSrcElement*/,
 127     SMILValue& aValue, bool& aPreventCachingOfSandwich) const {
 128   SMILValue val(&SVGLengthListSMILType::sSingleton);
 129   SVGLengthListAndInfo* llai = static_cast<SVGLengthListAndInfo*>(val.mU.mPtr);
 130   nsresult rv = llai->SetValueFromString(aStr);
 131   if (NS_SUCCEEDED(rv)) {
 132     llai->SetInfo(mElement, mAxis, mCanZeroPadList);
 133     aValue = std::move(val);
 134
 135     // If any of the lengths in the list depend on their context, then we must
 136     // prevent caching of the entire animation sandwich. This is because the
 137     // units of a length at a given index can change from sandwich layer to
 138     // layer, and indeed even be different within a single sandwich layer. If
 139     // any length in the result of an animation sandwich is the result of the
 140     // addition of lengths where one or more of those lengths is context
 141     // dependent, then naturally the resultant length is also context
 142     // dependent, regardless of whether its actual unit is context dependent or
 143     // not. Unfortunately normal invalidation mechanisms won't cause us to
 144     // recalculate the result of the sandwich if the context changes, so we
 145     // take the (substantial) performance hit of preventing caching of the
 146     // sandwich layer, causing the animation sandwich to be recalculated every
 147     // single sample.
 148
 149     aPreventCachingOfSandwich = false;
 150     for (uint32_t i = 0; i < llai->Length(); ++i) {
 151       uint8_t unit = (*llai)[i].GetUnit();
 152       if (unit == SVGLength_Binding::SVG_LENGTHTYPE_PERCENTAGE ||
 153           unit == SVGLength_Binding::SVG_LENGTHTYPE_EMS ||
 154           unit == SVGLength_Binding::SVG_LENGTHTYPE_EXS) {
 155         aPreventCachingOfSandwich = true;
 156         break;
 157       }
 158     }
 159   }
 160   return rv;
 161 }
 162
 163 SMILValue SVGAnimatedLengthList::SMILAnimatedLengthList::GetBaseValue() const {
 164   // To benefit from Return Value Optimization and avoid copy constructor calls
 165   // due to our use of return-by-value, we must return the exact same object
 166   // from ALL return points. This function must only return THIS variable:
 167   SMILValue val;
 168
 169   SMILValue tmp(&SVGLengthListSMILType::sSingleton);
 170   SVGLengthListAndInfo* llai = static_cast<SVGLengthListAndInfo*>(tmp.mU.mPtr);
 171   nsresult rv = llai->CopyFrom(mVal->mBaseVal);
 172   if (NS_SUCCEEDED(rv)) {
 173     llai->SetInfo(mElement, mAxis, mCanZeroPadList);
 174     val = std::move(tmp);
 175   }
 176   return val;
 177 }
 178
 179 nsresult SVGAnimatedLengthList::SMILAnimatedLengthList::SetAnimValue(
 180     const SMILValue& aValue) {
 181   NS_ASSERTION(aValue.mType == &SVGLengthListSMILType::sSingleton,
 182                "Unexpected type to assign animated value");
 183   if (aValue.mType == &SVGLengthListSMILType::sSingleton) {
 184     mVal->SetAnimValue(*static_cast<SVGLengthListAndInfo*>(aValue.mU.mPtr),
 185                        mElement, mAttrEnum);
 186   }
 187   return NS_OK;
 188 }
 189
 190 void SVGAnimatedLengthList::SMILAnimatedLengthList::ClearAnimValue() {
 191   if (mVal->mAnimVal) {
 192     mVal->ClearAnimValue(mElement, mAttrEnum);
 193   }
 194 }
 195
 196 }  // namespace mozilla