/* -*- 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/. */

#ifndef MOZILLA_SVGPOINTLIST_H__

#define MOZILLA_SVGPOINTLIST_H__

#include "nsCOMPtr.h"

#include "nsDebug.h"

#include "nsIContent.h"

#include "nsINode.h"

#include "nsIWeakReferenceUtils.h"

#include "nsSVGElement.h"

#include "nsTArray.h"

#include "SVGPoint.h"

#include <string.h>

namespace mozilla {

class nsISVGPoint;

/**

 * ATTENTION! WARNING! WATCH OUT!!

 *

 * Consumers that modify objects of this type absolutely MUST keep the DOM

 * wrappers for those lists (if any) in sync!! That's why this class is so

 * locked down.

 *

 * The DOM wrapper class for this class is DOMSVGPointList.

 */

class SVGPointList

{

  friend class mozilla::nsISVGPoint;

  friend class SVGAnimatedPointList;

  friend class DOMSVGPointList;

  friend class DOMSVGPoint;

public:

  SVGPointList(){}

  ~SVGPointList(){}

  // Only methods that don't make/permit modification to this list are public.

  // Only our friend classes can access methods that may change us.

  /// This may return an incomplete string on OOM, but that's acceptable.

  void GetValueAsString(nsAString& aValue) const;

  bool IsEmpty() const {

    return mItems.IsEmpty();

  }

  uint32_t Length() const {

    return mItems.Length();

  }

  const SVGPoint& operator[](uint32_t aIndex) const {

    return mItems[aIndex];

  }

  bool operator==(const SVGPointList& rhs) const {

    // memcmp can be faster than |mItems == rhs.mItems|

    return mItems.Length() == rhs.mItems.Length() &&

           memcmp(mItems.Elements(), rhs.mItems.Elements(),

                  mItems.Length() * sizeof(SVGPoint)) == 0;

  }

  bool SetCapacity(uint32_t aSize) {

    return mItems.SetCapacity(aSize, fallible);

  }

  void Compact() {

    mItems.Compact();

  }

  // Access to methods that can modify objects of this type is deliberately

  // limited. This is to reduce the chances of someone modifying objects of

  // this type without taking the necessary steps to keep DOM wrappers in sync.

  // If you need wider access to these methods, consider adding a method to

  // SVGAnimatedPointList and having that class act as an intermediary so it

  // can take care of keeping DOM wrappers in sync.

protected:

  /**

   * This may fail on OOM if the internal capacity needs to be increased, in

   * which case the list will be left unmodified.

   */

  nsresult CopyFrom(const SVGPointList& rhs);

  SVGPoint& operator[](uint32_t aIndex) {

    return mItems[aIndex];

  }

  /**

   * This may fail (return false) on OOM if the internal capacity is being

   * increased, in which case the list will be left unmodified.

   */

  bool SetLength(uint32_t aNumberOfItems) {

    return mItems.SetLength(aNumberOfItems, fallible);

  }

private:

  // Marking the following private only serves to show which methods are only

  // used by our friend classes (as opposed to our subclasses) - it doesn't

  // really provide additional safety.

  nsresult SetValueFromString(const nsAString& aValue);

  void Clear() {

    mItems.Clear();

  }

  bool InsertItem(uint32_t aIndex, const SVGPoint &aPoint) {

    if (aIndex >= mItems.Length()) {

      aIndex = mItems.Length();

    }

    return !!mItems.InsertElementAt(aIndex, aPoint, fallible);

  }

  void ReplaceItem(uint32_t aIndex, const SVGPoint &aPoint) {

    MOZ_ASSERT(aIndex < mItems.Length(),

               "DOM wrapper caller should have raised INDEX_SIZE_ERR");

    mItems[aIndex] = aPoint;

  }

  void RemoveItem(uint32_t aIndex) {

    MOZ_ASSERT(aIndex < mItems.Length(),

               "DOM wrapper caller should have raised INDEX_SIZE_ERR");

    mItems.RemoveElementAt(aIndex);

  }

  bool AppendItem(SVGPoint aPoint) {

    return !!mItems.AppendElement(aPoint, fallible);

  }

protected:

  /* See SVGLengthList for the rationale for using FallibleTArray<SVGPoint> instead

   * of FallibleTArray<SVGPoint, 1>.

   */

  FallibleTArray<SVGPoint> mItems;

};

/**

 * This SVGPointList subclass is for SVGPointListSMILType which needs a

 * mutable version of SVGPointList. Instances of this class do not have

 * DOM wrappers that need to be kept in sync, so we can safely expose any

 * protected base class methods required by the SMIL code.

 *

 * This class contains a strong reference to the element that instances of

 * this class are being used to animate. This is because the SMIL code stores

 * instances of this class in nsSMILValue objects, some of which are cached.

 * Holding a strong reference to the element here prevents the element from

 * disappearing out from under the SMIL code unexpectedly.

 */

class SVGPointListAndInfo : public SVGPointList

{

public:

  explicit SVGPointListAndInfo(nsSVGElement *aElement = nullptr)

    : mElement(do_GetWeakReference(static_cast<nsINode*>(aElement)))

  {}

  void SetInfo(nsSVGElement *aElement) {

    mElement = do_GetWeakReference(static_cast<nsINode*>(aElement));

  }

  nsSVGElement* Element() const {

    nsCOMPtr<nsIContent> e = do_QueryReferent(mElement);

    return static_cast<nsSVGElement*>(e.get());

  }

  /**

   * Returns true if this object is an "identity" value, from the perspective

   * of SMIL. In other words, returns true until the initial value set up in

   * SVGPointListSMILType::Init() has been changed with a SetInfo() call.

   */

  bool IsIdentity() const {

    if (!mElement) {

      MOZ_ASSERT(IsEmpty(), "target element propagation failure");

      return true;

    }

    return false;

  }

  nsresult CopyFrom(const SVGPointListAndInfo& rhs) {

    mElement = rhs.mElement;

    return SVGPointList::CopyFrom(rhs);

  }

  /**

   * Exposed so that SVGPointList baseVals can be copied to

   * SVGPointListAndInfo objects. Note that callers should also call

   * SetElement() when using this method!

   */

  nsresult CopyFrom(const SVGPointList& rhs) {

    return SVGPointList::CopyFrom(rhs);

  }

  const SVGPoint& operator[](uint32_t aIndex) const {

    return SVGPointList::operator[](aIndex);

  }

  SVGPoint& operator[](uint32_t aIndex) {

    return SVGPointList::operator[](aIndex);

  }

  bool SetLength(uint32_t aNumberOfItems) {

    return SVGPointList::SetLength(aNumberOfItems);

  }

private:

  // We must keep a weak reference to our element because we may belong to a

  // cached baseVal nsSMILValue. See the comments starting at:

  // https://bugzilla.mozilla.org/show_bug.cgi?id=515116#c15

  // See also https://bugzilla.mozilla.org/show_bug.cgi?id=653497

  nsWeakPtr mElement;

};

} // namespace mozilla

#endif // MOZILLA_SVGPOINTLIST_H__