Reland of Make FrameSelection to hold non-canonicalized positions

third_party/WebKit/Source/core/editing/SelectionEditor.h

 /*
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  *
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  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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 #ifndef SelectionEditor_h
 #define SelectionEditor_h
 
+#include "core/dom/SynchronousMutationObserver.h"
 #include "core/editing/FrameSelection.h"
+#include "core/editing/SelectionTemplate.h"
 #include "core/events/EventDispatchResult.h"
 
 namespace blink {
 
 // TODO(yosin): We will rename |SelectionEditor| to appropriate name since
 // it is no longer have a changing selection functionality, it was moved to
 // |SelectionModifier| class.
-class SelectionEditor final
-    : public GarbageCollectedFinalized<SelectionEditor> {
+class SelectionEditor final : public GarbageCollectedFinalized<SelectionEditor>,
+                              public SynchronousMutationObserver {
   WTF_MAKE_NONCOPYABLE(SelectionEditor);
+  USING_GARBAGE_COLLECTED_MIXIN(SelectionEditor);
 
  public:
   static SelectionEditor* create(LocalFrame& frame) {
     return new SelectionEditor(frame);
   }
   virtual ~SelectionEditor();
   void dispose();
 
-  bool hasEditableStyle() const { return m_selection.hasEditableStyle(); }
-  bool isContentEditable() const { return m_selection.isContentEditable(); }
-  bool isContentRichlyEditable() const {
-    return m_selection.isContentRichlyEditable();
-  }
-
-  bool setSelectedRange(const EphemeralRange&,
-                        TextAffinity,
-                        SelectionDirectionalMode,
-                        FrameSelection::SetSelectionOptions);
+  bool hasEditableStyle() const;
+  bool isContentEditable() const;
+  bool isContentRichlyEditable() const;
 
   template <typename Strategy>
   const VisibleSelectionTemplate<Strategy>& visibleSelection() const;
-  void setVisibleSelection(const VisibleSelection&,
-                           FrameSelection::SetSelectionOptions);
-  void setVisibleSelection(const VisibleSelectionInFlatTree&,
-                           FrameSelection::SetSelectionOptions);
+  const SelectionInDOMTree& selectionInDOMTree() const;
 
-  void setWithoutValidation(const Position& base, const Position& extent);
+  const VisibleSelection& computeVisibleSelectionInDOMTree() const;
+  const VisibleSelectionInFlatTree& computeVisibleSelectionInFlatTree() const;
+  void setSelection(const SelectionInDOMTree&);
 
   void documentAttached(Document*);
-  void documentDetached(const Document&);
 
   // If this FrameSelection has a logical range which is still valid, this
   // function return its clone. Otherwise, the return value from underlying
   // |VisibleSelection|'s |firstRange()| is returned.
   Range* firstRange() const;
 
   // There functions are exposed for |FrameSelection|.
   void resetLogicalRange();
   void setLogicalRange(Range*);
 
   // Updates |m_selection| and |m_selectionInFlatTree| with up-to-date
   // layout if needed.
   void updateIfNeeded();
 
   void cacheRangeOfDocument(Range*);
   Range* documentCachedRange() const;
   void clearDocumentCachedRange();
 
   DECLARE_TRACE();
 
  private:
   explicit SelectionEditor(LocalFrame&);
 
-  const Document& document() const;
+  Document& document() const;
   LocalFrame* frame() const { return m_frame.get(); }
 
+  void assertSelectionValid() const;
   void clearVisibleSelection();
+  void markCacheDirty();
   bool shouldAlwaysUseDirectionalSelection() const;
 
-  Member<Document> m_document;
+  // VisibleSelection cache related
+  bool needsUpdateVisibleSelection() const;
+  void updateCachedVisibleSelectionIfNeeded() const;
+
+  void didFinishTextChange(const Position& base, const Position& extent);
+  void didFinishDOMMutation();
+
+  // Implementation of |SynchronousMutationObsderver| member functions.
+  void contextDestroyed(Document*) final;
+  void didChangeChildren(const ContainerNode&) final;
+  void didMergeTextNodes(const Text& mergedNode,
+                         const NodeWithIndex& nodeToBeRemovedWithIndex,
+                         unsigned oldLength) final;
+  void didSplitTextNode(const Text&) final;
+  void didUpdateCharacterData(CharacterData*,
+                              unsigned offset,
+                              unsigned oldLength,
+                              unsigned newLength) final;
+  void nodeChildrenWillBeRemoved(ContainerNode&) final;
+  void nodeWillBeRemoved(Node&) final;
+
   Member<LocalFrame> m_frame;
 
-  VisibleSelection m_selection;
-  VisibleSelectionInFlatTree m_selectionInFlatTree;
-  bool m_observingVisibleSelection;
+  SelectionInDOMTree m_selection;
 
   // TODO(editing-dev): Removing |m_logicalRange|
   // The range specified by the user, which may not be visually canonicalized
   // (hence "logical"). This will be invalidated if the underlying
   // |VisibleSelection| changes. If that happens, this variable will
   // become |nullptr|, in which case logical positions == visible positions.
   Member<Range> m_logicalRange;
+
   // If document is root, document.getSelection().addRange(range) is cached on
   // this.
   Member<Range> m_cachedRange;
+
+  mutable VisibleSelection m_cachedVisibleSelectionInDOMTree;
+  mutable VisibleSelectionInFlatTree m_cachedVisibleSelectionInFlatTree;
+  mutable uint64_t m_styleVersion = static_cast<uint64_t>(-1);
+  mutable bool m_cacheIsDirty = false;
 };
 
 }  // namespace blink
 
 #endif  // SelectionEditor_h