/* -*- 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_ServoElementSnapshot_h

#define mozilla_ServoElementSnapshot_h

#include "mozilla/EventStates.h"

#include "mozilla/TypedEnumBits.h"

#include "mozilla/dom/BorrowedAttrInfo.h"

#include "mozilla/dom/Element.h"

#include "nsAttrName.h"

#include "nsAttrValue.h"

#include "nsChangeHint.h"

#include "nsGkAtoms.h"

#include "nsAtom.h"

namespace mozilla {

/**

 * A bitflags enum class used to determine what data does a ServoElementSnapshot

 * contains.

 */

enum class ServoElementSnapshotFlags : uint8_t

{

  State = 1 << 0,

  Attributes = 1 << 1,

  Id = 1 << 2,

  MaybeClass = 1 << 3,

  OtherPseudoClassState = 1 << 4,

};

MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(ServoElementSnapshotFlags)

/**

 * This class holds all non-tree-structural state of an element that might be

 * used for selector matching eventually.

 *

 * This means the attributes, and the element state, such as :hover, :active,

 * etc...

 */

class ServoElementSnapshot

{

  typedef dom::BorrowedAttrInfo BorrowedAttrInfo;

  typedef dom::Element Element;

  typedef EventStates::ServoType ServoStateType;

public:

  typedef ServoElementSnapshotFlags Flags;

  explicit ServoElementSnapshot(const Element&);

  ~ServoElementSnapshot()

  {

    MOZ_ASSERT(NS_IsMainThread());

    MOZ_COUNT_DTOR(ServoElementSnapshot);

  }

  bool HasAttrs() const { return HasAny(Flags::Attributes); }

  bool HasState() const { return HasAny(Flags::State); }

  bool HasOtherPseudoClassState() const

  {

    return HasAny(Flags::OtherPseudoClassState);

  }

  /**

   * Captures the given state (if not previously captured).

   */

  void AddState(EventStates aState)

  {

    if (!HasAny(Flags::State)) {

      mState = aState.ServoValue();

      mContains |= Flags::State;

    }

  }

  /**

   * Captures the given element attributes (if not previously captured).

   *

   * The attribute name and namespace are used to note which kind of attribute

   * has changed.

   */

  inline void AddAttrs(const Element&, int32_t aNameSpaceID, nsAtom* aAttribute);

  /**

   * Captures some other pseudo-class matching state not included in

   * EventStates.

   */

  void AddOtherPseudoClassState(const Element&);

  /**

   * Needed methods for attribute matching.

   */

  BorrowedAttrInfo GetAttrInfoAt(uint32_t aIndex) const

  {

    MOZ_ASSERT(HasAttrs());

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

      return BorrowedAttrInfo(nullptr, nullptr);

    }

    return BorrowedAttrInfo(&mAttrs[aIndex].mName, &mAttrs[aIndex].mValue);

  }

  const nsAttrValue* GetParsedAttr(nsAtom* aLocalName) const

  {

    return GetParsedAttr(aLocalName, kNameSpaceID_None);

  }

  const nsAttrValue* GetParsedAttr(nsAtom* aLocalName,

                                   int32_t aNamespaceID) const

  {

    MOZ_ASSERT(HasAttrs());

    uint32_t i, len = mAttrs.Length();

    if (aNamespaceID == kNameSpaceID_None) {

      // This should be the common case so lets make an optimized loop

      for (i = 0; i < len; ++i) {

        if (mAttrs[i].mName.Equals(aLocalName)) {

          return &mAttrs[i].mValue;

        }

      }

      return nullptr;

    }

    for (i = 0; i < len; ++i) {

      if (mAttrs[i].mName.Equals(aLocalName, aNamespaceID)) {

        return &mAttrs[i].mValue;

      }

    }

    return nullptr;

  }

  bool IsInChromeDocument() const { return mIsInChromeDocument; }

  bool SupportsLangAttr() const { return mSupportsLangAttr; }

  bool HasAny(Flags aFlags) const { return bool(mContains & aFlags); }

  bool IsTableBorderNonzero() const

  {

    MOZ_ASSERT(HasOtherPseudoClassState());

    return mIsTableBorderNonzero;

  }

  bool IsMozBrowserFrame() const

  {

    MOZ_ASSERT(HasOtherPseudoClassState());

    return mIsMozBrowserFrame;

  }

private:

  // TODO: Profile, a 1 or 2 element AutoTArray could be worth it, given we know

  // we're dealing with attribute changes when we take snapshots of attributes,

  // though it can be wasted space if we deal with a lot of state-only

  // snapshots.

  nsTArray<AttrArray::InternalAttr> mAttrs;

  nsAttrValue mClass;

  ServoStateType mState;

  Flags mContains;

  bool mIsHTMLElementInHTMLDocument : 1;

  bool mIsInChromeDocument : 1;

  bool mSupportsLangAttr : 1;

  bool mIsTableBorderNonzero : 1;

  bool mIsMozBrowserFrame : 1;

  bool mClassAttributeChanged : 1;

  bool mIdAttributeChanged : 1;

  bool mOtherAttributeChanged : 1;

};

inline void

ServoElementSnapshot::AddAttrs(const Element& aElement,

                               int32_t aNameSpaceID,

                               nsAtom* aAttribute)

{

  if (aNameSpaceID == kNameSpaceID_None) {

    if (aAttribute == nsGkAtoms::_class) {

      mClassAttributeChanged = true;

    } else if (aAttribute == nsGkAtoms::id) {

      mIdAttributeChanged = true;

    } else {

      mOtherAttributeChanged = true;

    }

  } else {

    mOtherAttributeChanged = true;

  }

  if (HasAttrs()) {

    return;

  }

  uint32_t attrCount = aElement.GetAttrCount();

  mAttrs.SetCapacity(attrCount);

  for (uint32_t i = 0; i < attrCount; ++i) {

    const BorrowedAttrInfo info = aElement.GetAttrInfoAt(i);

    MOZ_ASSERT(info);

    mAttrs.AppendElement(AttrArray::InternalAttr { *info.mName, *info.mValue });

  }

  mContains |= Flags::Attributes;

  if (aElement.HasID()) {

    mContains |= Flags::Id;

  }

  if (const nsAttrValue* classValue = aElement.GetClasses()) {

    // FIXME(emilio): It's pretty unfortunate that this is only relevant for

    // SVG, yet it's a somewhat expensive copy. We should be able to do

    // better!

    mClass = *classValue;

    mContains |= Flags::MaybeClass;

  }

}

} // namespace mozilla

#endif