/* -*- 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/. */

#include "SVGFragmentIdentifier.h"

#include "mozilla/dom/SVGSVGElement.h"

#include "mozilla/dom/SVGViewElement.h"

#include "nsContentUtils.h" // for nsCharSeparatedTokenizerTemplate

#include "nsSVGAnimatedTransformList.h"

#include "nsCharSeparatedTokenizer.h"

namespace mozilla {

using namespace dom;

static bool

IsMatchingParameter(const nsAString& aString, const nsAString& aParameterName)

{

  // The first two tests ensure aString.Length() > aParameterName.Length()

  // so it's then safe to do the third test

  return StringBeginsWith(aString, aParameterName) &&

         aString.Last() == ')' &&

         aString.CharAt(aParameterName.Length()) == '(';

}

inline bool

IgnoreWhitespace(char16_t aChar)

{

  return false;

}

static SVGViewElement*

GetViewElement(nsIDocument* aDocument, const nsAString& aId)

{

  Element* element = aDocument->GetElementById(aId);

  return (element && element->IsSVGElement(nsGkAtoms::view)) ?

            static_cast<SVGViewElement*>(element) : nullptr;

}

// Handles setting/clearing the root's mSVGView pointer.

class MOZ_RAII AutoSVGViewHandler

{

public:

  explicit AutoSVGViewHandler(SVGSVGElement* aRoot

                              MOZ_GUARD_OBJECT_NOTIFIER_PARAM)

    : mRoot(aRoot), mValid(false) {

    MOZ_GUARD_OBJECT_NOTIFIER_INIT;

    mWasOverridden = mRoot->UseCurrentView();

    mRoot->mSVGView = nullptr;

    mRoot->mCurrentViewID = nullptr;

  }

  ~AutoSVGViewHandler() {

    if (!mWasOverridden && !mValid) {

      // we weren't overridden before and we aren't

      // overridden now so nothing has changed.

      return;

    }

    if (mValid) {

      mRoot->mSVGView = mSVGView;

    }

    mRoot->InvalidateTransformNotifyFrame();

  }

  void CreateSVGView() {

    MOZ_ASSERT(!mSVGView, "CreateSVGView should not be called multiple times");

    mSVGView = new SVGView();

  }

  bool ProcessAttr(const nsAString& aToken, const nsAString &aParams) {

    MOZ_ASSERT(mSVGView, "CreateSVGView should have been called");

    // SVGViewAttributes may occur in any order, but each type may only occur

    // at most one time in a correctly formed SVGViewSpec.

    // If we encounter any attribute more than once or get any syntax errors

    // we're going to return false and cancel any changes.

    if (IsMatchingParameter(aToken, NS_LITERAL_STRING("viewBox"))) {

      if (mSVGView->mViewBox.IsExplicitlySet() ||

          NS_FAILED(mSVGView->mViewBox.SetBaseValueString(

                      aParams, mRoot, false))) {

        return false;

      }

    } else if (IsMatchingParameter(aToken, NS_LITERAL_STRING("preserveAspectRatio"))) {

      if (mSVGView->mPreserveAspectRatio.IsExplicitlySet() ||

          NS_FAILED(mSVGView->mPreserveAspectRatio.SetBaseValueString(

                      aParams, mRoot, false))) {

        return false;

      }

    } else if (IsMatchingParameter(aToken, NS_LITERAL_STRING("transform"))) {

      if (mSVGView->mTransforms) {

        return false;

      }

      mSVGView->mTransforms = new nsSVGAnimatedTransformList();

      if (NS_FAILED(mSVGView->mTransforms->SetBaseValueString(aParams, mRoot))) {

        return false;

      }

    } else if (IsMatchingParameter(aToken, NS_LITERAL_STRING("zoomAndPan"))) {

      if (mSVGView->mZoomAndPan.IsExplicitlySet()) {

        return false;

      }

      nsAtom* valAtom = NS_GetStaticAtom(aParams);

      if (!valAtom ||

          NS_FAILED(mSVGView->mZoomAndPan.SetBaseValueAtom(

                      valAtom, mRoot))) {

        return false;

      }

    } else {

      return false;

    }

    return true;

  }

  void SetValid() {

    mValid = true;

  }

private:

  SVGSVGElement*     mRoot;

  nsAutoPtr<SVGView> mSVGView;

  bool               mValid;

  bool               mWasOverridden;

  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER

};

bool

SVGFragmentIdentifier::ProcessSVGViewSpec(const nsAString& aViewSpec,

                                          SVGSVGElement* aRoot)

{

  AutoSVGViewHandler viewHandler(aRoot);

  if (!IsMatchingParameter(aViewSpec, NS_LITERAL_STRING("svgView"))) {

    return false;

  }

  // Each token is a SVGViewAttribute

  int32_t bracketPos = aViewSpec.FindChar('(');

  uint32_t lengthOfViewSpec = aViewSpec.Length() - bracketPos - 2;

  nsCharSeparatedTokenizerTemplate<IgnoreWhitespace> tokenizer(

    Substring(aViewSpec, bracketPos + 1, lengthOfViewSpec), ';');

  if (!tokenizer.hasMoreTokens()) {

    return false;

  }

  viewHandler.CreateSVGView();

  do {

    nsAutoString token(tokenizer.nextToken());

    bracketPos = token.FindChar('(');

    if (bracketPos < 1 || token.Last() != ')') {

      // invalid SVGViewAttribute syntax

      return false;

    }

    const nsAString &params =

      Substring(token, bracketPos + 1, token.Length() - bracketPos - 2);

    if (!viewHandler.ProcessAttr(token, params)) {

      return false;

    }

  } while (tokenizer.hasMoreTokens());

  viewHandler.SetValid();

  return true;

}

bool

SVGFragmentIdentifier::ProcessFragmentIdentifier(nsIDocument* aDocument,

                                                 const nsAString& aAnchorName)

{

  MOZ_ASSERT(aDocument->GetRootElement()->IsSVGElement(nsGkAtoms::svg),

             "expecting an SVG root element");

  SVGSVGElement* rootElement =

    static_cast<SVGSVGElement*>(aDocument->GetRootElement());

  const SVGViewElement* viewElement = GetViewElement(aDocument, aAnchorName);

  if (viewElement) {

    if (!rootElement->mCurrentViewID) {

      rootElement->mCurrentViewID = new nsString();

    }

    *rootElement->mCurrentViewID = aAnchorName;

    rootElement->mSVGView = nullptr;

    rootElement->InvalidateTransformNotifyFrame();

    // not an svgView()-style fragment identifier, return false so the caller

    // continues processing to match any :target pseudo elements

    return false;

  }

  return ProcessSVGViewSpec(aAnchorName, rootElement);

}

} // namespace mozilla