/* -*- 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 DISPLAYLISTCLIPSTATE_H_

#define DISPLAYLISTCLIPSTATE_H_

#include "DisplayItemClip.h"

#include "DisplayItemClipChain.h"

#include "mozilla/DebugOnly.h"

class nsIFrame;

class nsIScrollableFrame;

class nsDisplayListBuilder;

namespace mozilla {

/**

 * All clip coordinates are in appunits relative to the reference frame

 * for the display item we're building.

 */

class DisplayListClipState

{

public:

  DisplayListClipState()

    : mClipChainContentDescendants(nullptr)

    , mClipChainContainingBlockDescendants(nullptr)

    , mCurrentCombinedClipChain(nullptr)

    , mCurrentCombinedClipChainIsValid(false)

  {

  }

  /**

   * Returns intersection of mClipChainContainingBlockDescendants and

   * mClipChainContentDescendants, allocated on aBuilder's arena.

   */

  const DisplayItemClipChain* GetCurrentCombinedClipChain(

    nsDisplayListBuilder* aBuilder);

  const DisplayItemClipChain* GetClipChainForContainingBlockDescendants() const

  {

    return mClipChainContainingBlockDescendants;

  }

  const DisplayItemClipChain* GetClipChainForContentDescendants() const

  {

    return mClipChainContentDescendants;

  }

  const ActiveScrolledRoot* GetContentClipASR() const

  {

    return mClipChainContentDescendants ? mClipChainContentDescendants->mASR

                                        : nullptr;

  }

  class AutoSaveRestore;

  class AutoClipContainingBlockDescendantsToContentBox;

  class AutoClipMultiple;

  enum

  {

    ASSUME_DRAWING_RESTRICTED_TO_CONTENT_RECT = 0x01

  };

private:

  void Clear()

  {

    mClipChainContentDescendants = nullptr;

    mClipChainContainingBlockDescendants = nullptr;

    mCurrentCombinedClipChain = nullptr;

    mCurrentCombinedClipChainIsValid = false;

  }

  void SetClipChainForContainingBlockDescendants(

    const DisplayItemClipChain* aClipChain)

  {

    mClipChainContainingBlockDescendants = aClipChain;

    InvalidateCurrentCombinedClipChain(aClipChain ? aClipChain->mASR : nullptr);

  }

  /**

   * Intersects the given clip rect (with optional aRadii) with the current

   * mClipContainingBlockDescendants and sets mClipContainingBlockDescendants to

   * the result, stored in aClipOnStack.

   */

  void ClipContainingBlockDescendants(nsDisplayListBuilder* aBuilder,

                                      const nsRect& aRect,

                                      const nscoord* aRadii,

                                      DisplayItemClipChain& aClipChainOnStack);

  void ClipContentDescendants(nsDisplayListBuilder* aBuilder,

                              const nsRect& aRect,

                              const nscoord* aRadii,

                              DisplayItemClipChain& aClipChainOnStack);

  void ClipContentDescendants(nsDisplayListBuilder* aBuilder,

                              const nsRect& aRect,

                              const nsRect& aRoundedRect,

                              const nscoord* aRadii,

                              DisplayItemClipChain& aClipChainOnStack);

  void InvalidateCurrentCombinedClipChain(

    const ActiveScrolledRoot* aInvalidateUpTo);

  /**

   * Clips containing-block descendants to the frame's content-box,

   * taking border-radius into account.

   * If aFlags contains ASSUME_DRAWING_RESTRICTED_TO_CONTENT_RECT then

   * we assume display items will not draw outside the content rect, so

   * clipping is only required if there is a border-radius. This is an

   * optimization to reduce the amount of clipping required.

   */

  void ClipContainingBlockDescendantsToContentBox(

    nsDisplayListBuilder* aBuilder,

    nsIFrame* aFrame,

    DisplayItemClipChain& aClipChainOnStack,

    uint32_t aFlags);

  /**

   * All content descendants (i.e. following placeholder frames to their

   * out-of-flows if necessary) should be clipped by

   * mClipChainContentDescendants. Null if no clipping applies.

   */

  const DisplayItemClipChain* mClipChainContentDescendants;

  /**

   * All containing-block descendants (i.e. frame descendants), including

   * display items for the current frame, should be clipped by

   * mClipChainContainingBlockDescendants.

   * Null if no clipping applies.

   */

  const DisplayItemClipChain* mClipChainContainingBlockDescendants;

  /**

   * The intersection of mClipChainContentDescendants and

   * mClipChainContainingBlockDescendants.

   * Allocated in the nsDisplayListBuilder arena. Null if none has been

   * allocated or both mClipChainContentDescendants and

   * mClipChainContainingBlockDescendants are null.

   */

  const DisplayItemClipChain* mCurrentCombinedClipChain;

  bool mCurrentCombinedClipChainIsValid;

};

/**

 * A class to automatically save and restore the current clip state. Also

 * offers methods for modifying the clip state. Only one modification is allowed

 * to be in scope at a time using one of these objects; multiple modifications

 * require nested objects. The interface is written this way to prevent

 * dangling pointers to DisplayItemClips.

 */

class DisplayListClipState::AutoSaveRestore

{

public:

  explicit AutoSaveRestore(nsDisplayListBuilder* aBuilder);

  void Restore()

  {

    mState = mSavedState;

#ifdef DEBUG

    mRestored = true;

#endif

  }

  ~AutoSaveRestore() { Restore(); }

  void Clear()

  {

    NS_ASSERTION(!mRestored, "Already restored!");

    mState.Clear();

#ifdef DEBUG

    mClipUsed = false;

#endif

  }

  void SetClipChainForContainingBlockDescendants(

    const DisplayItemClipChain* aClipChain)

  {

    mState.SetClipChainForContainingBlockDescendants(aClipChain);

  }

  /**

   * Intersects the given clip rect (with optional aRadii) with the current

   * mClipContainingBlockDescendants and sets mClipContainingBlockDescendants to

   * the result, stored in aClipOnStack.

   */

  void ClipContainingBlockDescendants(const nsRect& aRect,

                                      const nscoord* aRadii = nullptr)

  {

    NS_ASSERTION(!mRestored, "Already restored!");

    NS_ASSERTION(!mClipUsed, "mClip already used");

#ifdef DEBUG

    mClipUsed = true;

#endif

    mState.ClipContainingBlockDescendants(mBuilder, aRect, aRadii, mClipChain);

  }

  void ClipContentDescendants(const nsRect& aRect,

                              const nscoord* aRadii = nullptr)

  {

    NS_ASSERTION(!mRestored, "Already restored!");

    NS_ASSERTION(!mClipUsed, "mClip already used");

#ifdef DEBUG

    mClipUsed = true;

#endif

    mState.ClipContentDescendants(mBuilder, aRect, aRadii, mClipChain);

  }

  void ClipContentDescendants(const nsRect& aRect,

                              const nsRect& aRoundedRect,

                              const nscoord* aRadii = nullptr)

  {

    NS_ASSERTION(!mRestored, "Already restored!");

    NS_ASSERTION(!mClipUsed, "mClip already used");

#ifdef DEBUG

    mClipUsed = true;

#endif

    mState.ClipContentDescendants(

      mBuilder, aRect, aRoundedRect, aRadii, mClipChain);

  }

  /**

   * Clips containing-block descendants to the frame's content-box,

   * taking border-radius into account.

   * If aFlags contains ASSUME_DRAWING_RESTRICTED_TO_CONTENT_RECT then

   * we assume display items will not draw outside the content rect, so

   * clipping is only required if there is a border-radius. This is an

   * optimization to reduce the amount of clipping required.

   */

  void ClipContainingBlockDescendantsToContentBox(

    nsDisplayListBuilder* aBuilder,

    nsIFrame* aFrame,

    uint32_t aFlags = 0)

  {

    NS_ASSERTION(!mRestored, "Already restored!");

    NS_ASSERTION(!mClipUsed, "mClip already used");

#ifdef DEBUG

    mClipUsed = true;

#endif

    mState.ClipContainingBlockDescendantsToContentBox(

      aBuilder, aFrame, mClipChain, aFlags);

  }

protected:

  nsDisplayListBuilder* mBuilder;

  DisplayListClipState& mState;

  DisplayListClipState mSavedState;

  DisplayItemClipChain mClipChain;

#ifdef DEBUG

  bool mClipUsed;

  bool mRestored;

#endif

};

class DisplayListClipState::AutoClipContainingBlockDescendantsToContentBox

  : public AutoSaveRestore

{

public:

  AutoClipContainingBlockDescendantsToContentBox(nsDisplayListBuilder* aBuilder,

                                                 nsIFrame* aFrame,

                                                 uint32_t aFlags = 0)

    : AutoSaveRestore(aBuilder)

  {

#ifdef DEBUG

    mClipUsed = true;

#endif

    mState.ClipContainingBlockDescendantsToContentBox(

      aBuilder, aFrame, mClipChain, aFlags);

  }

};

/**

 * Do not use this outside of nsFrame::BuildDisplayListForChild, use

 * multiple AutoSaveRestores instead. We provide this class just to ensure

 * BuildDisplayListForChild is as efficient as possible.

 */

class DisplayListClipState::AutoClipMultiple : public AutoSaveRestore

{

public:

  explicit AutoClipMultiple(nsDisplayListBuilder* aBuilder)

    : AutoSaveRestore(aBuilder)

#ifdef DEBUG

    , mExtraClipUsed(false)

#endif

  {

  }

  /**

   * Intersects the given clip rect (with optional aRadii) with the current

   * mClipContainingBlockDescendants and sets mClipContainingBlockDescendants to

   * the result, stored in aClipOnStack.

   */

  void ClipContainingBlockDescendantsExtra(const nsRect& aRect,

                                           const nscoord* aRadii)

  {

    NS_ASSERTION(!mRestored, "Already restored!");

    NS_ASSERTION(!mExtraClipUsed, "mExtraClip already used");

#ifdef DEBUG

    mExtraClipUsed = true;

#endif

    mState.ClipContainingBlockDescendants(

      mBuilder, aRect, aRadii, mExtraClipChain);

  }

protected:

  DisplayItemClipChain mExtraClipChain;

#ifdef DEBUG

  bool mExtraClipUsed;

#endif

};

} // namespace mozilla

#endif /* DISPLAYLISTCLIPSTATE_H_ */