text: /*
   * Copyright (C) 2004, 2008 Apple Inc. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
   * 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,
   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
   * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
   */
  
  #ifndef VisiblePosition_h
  #define VisiblePosition_h
  
  #include "Node.h"
  #include "Position.h"
  #include "TextDirection.h"
  
  namespace WebCore {
  
  // VisiblePosition default affinity is downstream because
  // the callers do not really care (they just want the
  // deep position without regard to line position), and this
  // is cheaper than UPSTREAM
  #define VP_DEFAULT_AFFINITY DOWNSTREAM
  
  // Callers who do not know where on the line the position is,
  // but would like UPSTREAM if at a line break or DOWNSTREAM
  // otherwise, need a clear way to specify that.  The
  // constructors auto-correct UPSTREAM to DOWNSTREAM if the
  // position is not at a line break.
  #define VP_UPSTREAM_IF_POSSIBLE UPSTREAM
  
  class InlineBox;
  
  enum StayInEditableContent { MayLeaveEditableContent, MustStayInEditableContent };
  
  class VisiblePosition {
  public:
      // NOTE: UPSTREAM affinity will be used only if pos is at end of a wrapped line,
      // otherwise it will be converted to DOWNSTREAM
      VisiblePosition() : m_affinity(VP_DEFAULT_AFFINITY) { }
      VisiblePosition(Node*, int offset, EAffinity);
      VisiblePosition(const Position&, EAffinity = VP_DEFAULT_AFFINITY);
  
      void clear() { m_deepPosition.clear(); }
  
      bool isNull() const { return m_deepPosition.isNull(); }
      bool isNotNull() const { return m_deepPosition.isNotNull(); }
  
      Position deepEquivalent() const { return m_deepPosition; }
      EAffinity affinity() const { ASSERT(m_affinity == UPSTREAM || m_affinity == DOWNSTREAM); return m_affinity; }
      void setAffinity(EAffinity affinity) { m_affinity = affinity; }
  
      // FIXME: Change the following functions' parameter from a boolean to StayInEditableContent.
  
      // next() and previous() will increment/decrement by a character cluster.
      VisiblePosition next(bool stayInEditableContent = false) const;
      VisiblePosition previous(bool stayInEditableContent = false) const;
      VisiblePosition honorEditableBoundaryAtOrBefore(const VisiblePosition&) const;
      VisiblePosition honorEditableBoundaryAtOrAfter(const VisiblePosition&) const;
  
      VisiblePosition left(bool stayInEditableContent = false) const;
      VisiblePosition right(bool stayInEditableContent = false) const;
  
      UChar32 characterAfter() const;
      UChar32 characterBefore() const { return previous().characterAfter(); }
      
      void debugPosition(const char* msg = "") const;
      
      Element* rootEditableElement() const { return m_deepPosition.isNotNull() ? m_deepPosition.node()->rootEditableElement() : 0; }
      
      void getInlineBoxAndOffset(InlineBox*& inlineBox, int& caretOffset) const
      {
          m_deepPosition.getInlineBoxAndOffset(m_affinity, inlineBox, caretOffset);
      }
  
      void getInlineBoxAndOffset(TextDirection primaryDirection, InlineBox*& inlineBox, int& caretOffset) const
      {
          m_deepPosition.getInlineBoxAndOffset(m_affinity, primaryDirection, inlineBox, caretOffset);
      }
  
      // Rect is local to the returned renderer
      IntRect localCaretRect(RenderObject*&) const;
      // Bounds of (possibly transformed) caret in absolute coords
      IntRect absoluteCaretBounds() const;
      // Abs x position of the caret ignoring transforms.
      // FIXME: navigation with transforms should be smarter.
      int xOffsetForVerticalNavigation() const;
      
  #ifndef NDEBUG
      void formatForDebugger(char* buffer, unsigned length) const;
      void showTreeForThis() const;
  #endif
      
  private:
      void init(const Position&, EAffinity);
      Position canonicalPosition(const Position&);
  
      Position leftVisuallyDistinctCandidate() const;
      Position rightVisuallyDistinctCandidate() const;
  
      Position m_deepPosition;
      EAffinity m_affinity;
  };
  
  // FIXME: This shouldn't ignore affinity.
  inline bool operator==(const VisiblePosition& a, const VisiblePosition& b)
  {
      return a.deepEquivalent() == b.deepEquivalent();
  }
   
  inline bool operator!=(const VisiblePosition& a, const VisiblePosition& b)
  {
      return !(a == b);
  }
  
  PassRefPtr<Range> makeRange(const VisiblePosition&, const VisiblePosition&);
  bool setStart(Range*, const VisiblePosition&);
  bool setEnd(Range*, const VisiblePosition&);
  VisiblePosition startVisiblePosition(const Range*, EAffinity);
  VisiblePosition endVisiblePosition(const Range*, EAffinity);
  
  Node *enclosingBlockFlowElement(const VisiblePosition&);
  
  bool isFirstVisiblePositionInNode(const VisiblePosition&, const Node*);
  bool isLastVisiblePositionInNode(const VisiblePosition&, const Node*);
  
  } // namespace WebCore
  
  #ifndef NDEBUG
  // Outside the WebCore namespace for ease of invocation from gdb.
  void showTree(const WebCore::VisiblePosition*);
  void showTree(const WebCore::VisiblePosition&);
  #endif
  
  #endif // VisiblePosition_h
  