1 files changed, 122 insertions, 0 deletions
diff --git a/layout/base/nsFrameTraversal.h b/layout/base/nsFrameTraversal.h
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+++ b/layout/base/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