dom/svg/SVGFragmentIdentifier.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 "SVGFragmentIdentifier.h"
   8
   9 #include "mozilla/dom/SVGSVGElement.h"
  10 #include "mozilla/dom/SVGViewElement.h"
  11 #include "mozilla/SVGOuterSVGFrame.h"
  12 #include "nsCharSeparatedTokenizer.h"
  13 #include "SVGAnimatedTransformList.h"
  14
  15 namespace mozilla {
  16
  17 using namespace dom;
  18
  19 static bool IsMatchingParameter(const nsAString& aString,
  20                                 const nsAString& aParameterName) {
  21   // The first two tests ensure aString.Length() > aParameterName.Length()
  22   // so it's then safe to do the third test
  23   return StringBeginsWith(aString, aParameterName) && aString.Last() == ')' &&
  24          aString.CharAt(aParameterName.Length()) == '(';
  25 }
  26
  27 // Handles setting/clearing the root's mSVGView pointer.
  28 class MOZ_RAII AutoSVGViewHandler {
  29  public:
  30   explicit AutoSVGViewHandler(SVGSVGElement* aRoot)
  31       : mRoot(aRoot), mValid(false) {
  32     mWasOverridden = mRoot->UseCurrentView();
  33     mRoot->mSVGView = nullptr;
  34     mRoot->mCurrentViewID = nullptr;
  35   }
  36
  37   ~AutoSVGViewHandler() {
  38     if (!mWasOverridden && !mValid) {
  39       // we weren't overridden before and we aren't
  40       // overridden now so nothing has changed.
  41       return;
  42     }
  43     if (mValid) {
  44       mRoot->mSVGView = std::move(mSVGView);
  45     }
  46     mRoot->DidChangeSVGView();
  47     if (SVGOuterSVGFrame* osf = do_QueryFrame(mRoot->GetPrimaryFrame())) {
  48       osf->MaybeSendIntrinsicSizeAndRatioToEmbedder();
  49     }
  50   }
  51
  52   void CreateSVGView() {
  53     MOZ_ASSERT(!mSVGView, "CreateSVGView should not be called multiple times");
  54     mSVGView = MakeUnique<SVGView>();
  55   }
  56
  57   bool ProcessAttr(const nsAString& aToken, const nsAString& aParams) {
  58     MOZ_ASSERT(mSVGView, "CreateSVGView should have been called");
  59
  60     // SVGViewAttributes may occur in any order, but each type may only occur
  61     // at most one time in a correctly formed SVGViewSpec.
  62     // If we encounter any attribute more than once or get any syntax errors
  63     // we're going to return false and cancel any changes.
  64
  65     if (IsMatchingParameter(aToken, u"viewBox"_ns)) {
  66       if (mSVGView->mViewBox.IsExplicitlySet() ||
  67           NS_FAILED(
  68               mSVGView->mViewBox.SetBaseValueString(aParams, mRoot, false))) {
  69         return false;
  70       }
  71     } else if (IsMatchingParameter(aToken, u"preserveAspectRatio"_ns)) {
  72       if (mSVGView->mPreserveAspectRatio.IsExplicitlySet() ||
  73           NS_FAILED(mSVGView->mPreserveAspectRatio.SetBaseValueString(
  74               aParams, mRoot, false))) {
  75         return false;
  76       }
  77     } else if (IsMatchingParameter(aToken, u"transform"_ns)) {
  78       if (mSVGView->mTransforms) {
  79         return false;
  80       }
  81       mSVGView->mTransforms = MakeUnique<SVGAnimatedTransformList>();
  82       if (NS_FAILED(
  83               mSVGView->mTransforms->SetBaseValueString(aParams, mRoot))) {
  84         return false;
  85       }
  86     } else if (IsMatchingParameter(aToken, u"zoomAndPan"_ns)) {
  87       if (mSVGView->mZoomAndPan.IsExplicitlySet()) {
  88         return false;
  89       }
  90       nsAtom* valAtom = NS_GetStaticAtom(aParams);
  91       if (!valAtom || !mSVGView->mZoomAndPan.SetBaseValueAtom(valAtom, mRoot)) {
  92         return false;
  93       }
  94     } else {
  95       return false;
  96     }
  97     return true;
  98   }
  99
 100   void SetValid() { mValid = true; }
 101
 102  private:
 103   SVGSVGElement* mRoot;
 104   UniquePtr<SVGView> mSVGView;
 105   bool mValid;
 106   bool mWasOverridden;
 107 };
 108
 109 bool SVGFragmentIdentifier::ProcessSVGViewSpec(const nsAString& aViewSpec,
 110                                                SVGSVGElement* aRoot) {
 111   AutoSVGViewHandler viewHandler(aRoot);
 112
 113   if (!IsMatchingParameter(aViewSpec, u"svgView"_ns)) {
 114     return false;
 115   }
 116
 117   // Each token is a SVGViewAttribute
 118   int32_t bracketPos = aViewSpec.FindChar('(');
 119   uint32_t lengthOfViewSpec = aViewSpec.Length() - bracketPos - 2;
 120   nsCharSeparatedTokenizerTemplate<NS_TokenizerIgnoreNothing> tokenizer(
 121       Substring(aViewSpec, bracketPos + 1, lengthOfViewSpec), ';');
 122
 123   if (!tokenizer.hasMoreTokens()) {
 124     return false;
 125   }
 126   viewHandler.CreateSVGView();
 127
 128   do {
 129     nsAutoString token(tokenizer.nextToken());
 130
 131     bracketPos = token.FindChar('(');
 132     if (bracketPos < 1 || token.Last() != ')') {
 133       // invalid SVGViewAttribute syntax
 134       return false;
 135     }
 136
 137     const nsAString& params =
 138         Substring(token, bracketPos + 1, token.Length() - bracketPos - 2);
 139
 140     if (!viewHandler.ProcessAttr(token, params)) {
 141       return false;
 142     }
 143
 144   } while (tokenizer.hasMoreTokens());
 145
 146   viewHandler.SetValid();
 147   return true;
 148 }
 149
 150 bool SVGFragmentIdentifier::ProcessFragmentIdentifier(
 151     Document* aDocument, const nsAString& aAnchorName) {
 152   MOZ_ASSERT(aDocument->GetRootElement()->IsSVGElement(nsGkAtoms::svg),
 153              "expecting an SVG root element");
 154
 155   auto* rootElement = SVGSVGElement::FromNode(aDocument->GetRootElement());
 156
 157   const auto* viewElement =
 158       SVGViewElement::FromNodeOrNull(aDocument->GetElementById(aAnchorName));
 159
 160   if (viewElement) {
 161     if (!rootElement->mCurrentViewID) {
 162       rootElement->mCurrentViewID = MakeUnique<nsString>();
 163     }
 164     *rootElement->mCurrentViewID = aAnchorName;
 165     rootElement->mSVGView = nullptr;
 166     rootElement->InvalidateTransformNotifyFrame();
 167     if (nsIFrame* f = rootElement->GetPrimaryFrame()) {
 168       if (SVGOuterSVGFrame* osf = do_QueryFrame(f)) {
 169         osf->MaybeSendIntrinsicSizeAndRatioToEmbedder();
 170       }
 171     }
 172     // not an svgView()-style fragment identifier, return false so the caller
 173     // continues processing to match any :target pseudo elements
 174     return false;
 175   }
 176
 177   return ProcessSVGViewSpec(aAnchorName, rootElement);
 178 }
 179
 180 }  // namespace mozilla