nsFrameTraversal.h

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/* -*- 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 NSFRAMETRAVERSAL_H

#define NSFRAMETRAVERSAL_H

#include <cstdint>

#include "mozilla/Attributes.h"

class nsIFrame;

class nsPresContext;

class MOZ_STACK_CLASS nsFrameIterator final {

 public:

  void First();

  void Next();

  nsIFrame* CurrentItem();

  bool IsDone();

  void Last();

  void Prev();

  inline nsIFrame* Traverse(bool aForward) {

    if (aForward) {

      Next();

    } else {

      Prev();

    return CurrentItem();

};

  enum class Type : uint8_t {

    // only leaf nodes

    Leaf,

    // "open tag" order

    PreOrder,

    // "close tag" order

    PostOrder,

};

  nsFrameIterator(nsPresContext* aPresContext, nsIFrame* aStart, Type aType,

                  bool aVisual, bool aLockInScrollView, bool aFollowOOFs,

                  bool aSkipPopupChecks, nsIFrame* aLimiter = nullptr);

  ~nsFrameIterator() = default;

 protected:

  void SetCurrent(nsIFrame* aFrame) { mCurrent = aFrame; }

  nsIFrame* GetCurrent() { return mCurrent; }

  nsIFrame* GetStart() { return mStart; }

  nsIFrame* GetLast() { return mLast; }

  void SetLast(nsIFrame* aFrame) { mLast = aFrame; }

  int8_t GetOffEdge() { return mOffEdge; }

  void SetOffEdge(int8_t aOffEdge) { mOffEdge = aOffEdge; }

/*

   Our own versions of the standard frame tree navigation

   methods, which, if the iterator is following out-of-flows,

   apply the following rules for placeholder frames:

   - If a frame HAS a placeholder frame, getting its parent

   gets the placeholder's parent.

   - If a frame's first child or next/prev sibling IS a

   placeholder frame, then we instead return the real frame.

   - If a frame HAS a placeholder frame, getting its next/prev

   sibling gets the placeholder frame's next/prev sibling.

   These are all applied recursively to support multiple levels of

   placeholders.

*/

  nsIFrame* GetParentFrame(nsIFrame* aFrame);

  // like GetParentFrame but returns null once a popup frame is reached

  nsIFrame* GetParentFrameNotPopup(nsIFrame* aFrame);

  nsIFrame* GetFirstChild(nsIFrame* aFrame);

  nsIFrame* GetLastChild(nsIFrame* aFrame);

  nsIFrame* GetNextSibling(nsIFrame* aFrame);

  nsIFrame* GetPrevSibling(nsIFrame* aFrame);

/*

   These methods are overridden by the bidi visual iterator to have the

   semantics of "get first child in visual order", "get last child in visual

   order", "get next sibling in visual order" and "get previous sibling in

   visual order".

*/

  nsIFrame* GetFirstChildInner(nsIFrame* aFrame);

  nsIFrame* GetLastChildInner(nsIFrame* aFrame);

  nsIFrame* GetNextSiblingInner(nsIFrame* aFrame);

  nsIFrame* GetPrevSiblingInner(nsIFrame* aFrame);

/**

   * Return the placeholder frame for aFrame if it has one, otherwise return

   * aFrame itself.

*/

  nsIFrame* GetPlaceholderFrame(nsIFrame* aFrame);

  bool IsPopupFrame(nsIFrame* aFrame);

  bool IsInvokerOpenPopoverFrame(nsIFrame* aFrame);

  nsPresContext* const mPresContext;

  const bool mLockScroll;

  const bool mFollowOOFs;

  const bool mSkipPopupChecks;

  const bool mVisual;

  const Type mType;

 private:

  nsIFrame* const mStart;

  nsIFrame* mCurrent;

  nsIFrame* mLast;  // the last one that was in current;

  nsIFrame* mLimiter;

  int8_t mOffEdge;  // 0= no -1 to far prev, 1 to far next;

};

#endif  // NSFRAMETRAVERSAL_H