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->InvalidateTransformNotifyFrame();
  47     if (nsIFrame* f = mRoot->GetPrimaryFrame()) {
  48       if (SVGOuterSVGFrame* osf = do_QueryFrame(f)) {
  49         osf->MaybeSendIntrinsicSizeAndRatioToEmbedder();
  50       }
  51     }
  52   }
  53
  54   void CreateSVGView() {
  55     MOZ_ASSERT(!mSVGView, "CreateSVGView should not be called multiple times");
  56     mSVGView = MakeUnique<SVGView>();
  57   }
  58
  59   bool ProcessAttr(const nsAString& aToken, const nsAString& aParams) {
  60     MOZ_ASSERT(mSVGView, "CreateSVGView should have been called");
  61
  62     // SVGViewAttributes may occur in any order, but each type may only occur
  63     // at most one time in a correctly formed SVGViewSpec.
  64     // If we encounter any attribute more than once or get any syntax errors
  65     // we're going to return false and cancel any changes.
  66
  67     if (IsMatchingParameter(aToken, u"viewBox"_ns)) {
  68       if (mSVGView->mViewBox.IsExplicitlySet() ||
  69           NS_FAILED(
  70               mSVGView->mViewBox.SetBaseValueString(aParams, mRoot, false))) {
  71         return false;
  72       }
  73     } else if (IsMatchingParameter(aToken, u"preserveAspectRatio"_ns)) {
  74       if (mSVGView->mPreserveAspectRatio.IsExplicitlySet() ||
  75           NS_FAILED(mSVGView->mPreserveAspectRatio.SetBaseValueString(
  76               aParams, mRoot, false))) {
  77         return false;
  78       }
  79     } else if (IsMatchingParameter(aToken, u"transform"_ns)) {
  80       if (mSVGView->mTransforms) {
  81         return false;
  82       }
  83       mSVGView->mTransforms = MakeUnique<SVGAnimatedTransformList>();
  84       if (NS_FAILED(
  85               mSVGView->mTransforms->SetBaseValueString(aParams, mRoot))) {
  86         return false;
  87       }
  88     } else if (IsMatchingParameter(aToken, u"zoomAndPan"_ns)) {
  89       if (mSVGView->mZoomAndPan.IsExplicitlySet()) {
  90         return false;
  91       }
  92       nsAtom* valAtom = NS_GetStaticAtom(aParams);
  93       if (!valAtom || !mSVGView->mZoomAndPan.SetBaseValueAtom(valAtom, mRoot)) {
  94         return false;
  95       }
  96     } else {
  97       return false;
  98     }
  99     return true;
 100   }
 101
 102   void SetValid() { mValid = true; }
 103
 104  private:
 105   SVGSVGElement* mRoot;
 106   UniquePtr<SVGView> mSVGView;
 107   bool mValid;
 108   bool mWasOverridden;
 109 };
 110
 111 bool SVGFragmentIdentifier::ProcessSVGViewSpec(const nsAString& aViewSpec,
 112                                                SVGSVGElement* aRoot) {
 113   AutoSVGViewHandler viewHandler(aRoot);
 114
 115   if (!IsMatchingParameter(aViewSpec, u"svgView"_ns)) {
 116     return false;
 117   }
 118
 119   // Each token is a SVGViewAttribute
 120   int32_t bracketPos = aViewSpec.FindChar('(');
 121   uint32_t lengthOfViewSpec = aViewSpec.Length() - bracketPos - 2;
 122   nsCharSeparatedTokenizerTemplate<NS_TokenizerIgnoreNothing> tokenizer(
 123       Substring(aViewSpec, bracketPos + 1, lengthOfViewSpec), ';');
 124
 125   if (!tokenizer.hasMoreTokens()) {
 126     return false;
 127   }
 128   viewHandler.CreateSVGView();
 129
 130   do {
 131     nsAutoString token(tokenizer.nextToken());
 132
 133     bracketPos = token.FindChar('(');
 134     if (bracketPos < 1 || token.Last() != ')') {
 135       // invalid SVGViewAttribute syntax
 136       return false;
 137     }
 138
 139     const nsAString& params =
 140         Substring(token, bracketPos + 1, token.Length() - bracketPos - 2);
 141
 142     if (!viewHandler.ProcessAttr(token, params)) {
 143       return false;
 144     }
 145
 146   } while (tokenizer.hasMoreTokens());
 147
 148   viewHandler.SetValid();
 149   return true;
 150 }
 151
 152 bool SVGFragmentIdentifier::ProcessFragmentIdentifier(
 153     Document* aDocument, const nsAString& aAnchorName) {
 154   MOZ_ASSERT(aDocument->GetRootElement()->IsSVGElement(nsGkAtoms::svg),
 155              "expecting an SVG root element");
 156
 157   auto* rootElement = SVGSVGElement::FromNode(aDocument->GetRootElement());
 158
 159   const auto* viewElement =
 160       SVGViewElement::FromNodeOrNull(aDocument->GetElementById(aAnchorName));
 161
 162   if (viewElement) {
 163     if (!rootElement->mCurrentViewID) {
 164       rootElement->mCurrentViewID = MakeUnique<nsString>();
 165     }
 166     *rootElement->mCurrentViewID = aAnchorName;
 167     rootElement->mSVGView = nullptr;
 168     rootElement->InvalidateTransformNotifyFrame();
 169     if (nsIFrame* f = rootElement->GetPrimaryFrame()) {
 170       if (SVGOuterSVGFrame* osf = do_QueryFrame(f)) {
 171         osf->MaybeSendIntrinsicSizeAndRatioToEmbedder();
 172       }
 173     }
 174     // not an svgView()-style fragment identifier, return false so the caller
 175     // continues processing to match any :target pseudo elements
 176     return false;
 177   }
 178
 179   return ProcessSVGViewSpec(aAnchorName, rootElement);
 180 }
 181
 182 }  // namespace mozilla