khtml_caret_p.h

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  /** constructs a new caret box line out of the given inline flow box
   * @param deleter deleter which handles alloc+dealloc of the object
   * @param baseFlowBox basic flow box which to create a caret line box from
   * @param seekBox seek this box within the constructed line
   * @param seekOutside denoting whether position is outside of seekBox
   * @param seekOutsideEnd whether at the outside end of seekBox
   * @param iter returns an iterator that corresponds to seekBox. If no suitable
   *	caret box exists, it will return end()
   * @param seekObject seek this render object within the constructed line.
   *	It will only be regarded if \c seekBox is 0. \c iter will then point
   *	to the first caret box whose render object matches.
   */
  static CaretBoxLine *constructCaretBoxLine(MassDeleter<CaretBoxLine> *deleter,
  	InlineFlowBox *baseFlowBox, InlineBox *seekBox, bool seekOutside,
        bool seekOutsideEnd, CaretBoxIterator &iter,
	RenderObject *seekObject = 0) /*KDE_NO_EXPORT*/;

  /** constructs a new caret box line for the given render block.
   * @param deleter deleter which handles alloc+dealloc of the object
   * @param cb render block or render replaced
   * @param outside true when line is to be constructed outside
   * @param outsideEnd true when the ending outside is meant
   * @param iter returns the iterator to the caret box representing the given
   *	position for \c cb
   */
  static CaretBoxLine *constructCaretBoxLine(MassDeleter<CaretBoxLine> *deleter,
  	RenderBox *cb, bool outside, bool outsideEnd, CaretBoxIterator &iter) /*KDE_NO_EXPORT*/;

#if DEBUG_CARETMODE > 0
  void dump(QTextStream &ts, const QString &ind) const;
  QString information() const
  {
    QString result;
    QTextStream ts(&result, IO_WriteOnly);
    dump(ts, QString::null);
    return result;
  }
#endif

protected:
  /** contains the seek parameters */
  struct SeekBoxParams {
    InlineBox *box;
    bool outside;
    bool outsideEnd;
    bool found;
    RenderObject *r;	// if box is 0, seek for equal render objects instead
    CaretBoxIterator &it;

    SeekBoxParams(InlineBox *box, bool outside, bool outsideEnd, RenderObject *obj, CaretBoxIterator &it)
        : box(box), outside(outside), outsideEnd(outsideEnd), found(false), r(obj), it(it)
    {}

    /** compares whether this seek box matches the given specification */
    bool equalsBox(const InlineBox *box, bool outside, bool outsideEnd) const
    {
      return (this->box && this->box == box
              || this->r == box->object())
          && this->outside == outside
          && (!this->outside || this->outsideEnd == outsideEnd);
    }
    /** compares whether this seek box matches the given caret box */
    bool operator ==(const CaretBox *cbox) const
    {
      return equalsBox(cbox->inlineBox(), cbox->isOutside(), cbox->isOutsideEnd());
    }
    /** checks whether this box matches the given iterator.
     *
     * On success, it sets \c found, and assigns the iterator to \c it.
     * @return true on match
     */
    bool check(const CaretBoxIterator &chit)
    {
      if (*this == *chit) {
        Q_ASSERT(!found);
        found = true;
        it = chit;
      }
      return found;
    }
  };

  /** recursively converts the given inline box into caret boxes and adds them
   * to this caret box line.
   *
   * It will additionally look for the caret box specified in SeekBoxParams.
   */
  void addConvertedInlineBox(InlineBox *, SeekBoxParams &) /*KDE_NO_EXPORT*/;

  /** creates and adds the edge of a generic inline box
   * @param box inline box
   * @param fm font metrics of inline box
   * @param left true to add left edge, false to add right edge
   * @param rtl true if direction is rtl
   */
  void addCreatedInlineBoxEdge(InlineBox *box, const QFontMetrics &fm,
  	bool left, bool rtl) /*KDE_NO_EXPORT*/;
  /** creates and adds the edge of an inline flow box
   * @param flowBox inline flow box
   * @param fm font metrics of inline flow box
   * @param left true to add left edge, false to add right edge
   * @param rtl true if direction is rtl
   */
  void addCreatedFlowBoxEdge(InlineFlowBox *flowBox, const QFontMetrics &fm,
  	bool left, bool rtl) /*KDE_NO_EXPORT*/;
  /** creates and adds the inside of an inline flow box
   * @param flowBox inline flow box
   * @param fm font metrics of inline flow box
   */
  void addCreatedFlowBoxInside(InlineFlowBox *flowBox, const QFontMetrics &fm) /*KDE_NO_EXPORT*/;

  friend class CaretBoxIterator;
};

typedef MassDeleter<CaretBoxLine> CaretBoxLineDeleter;

inline CaretBox *CaretBoxIterator::data() const { return cbl->caret_boxes[index]; }

/**
 * Iterates through the lines of a document.
 *
 * The line iterator becomes invalid when the associated LinearDocument object
 * is destroyed.
 * @since 3.2
 * @internal
 * @author Leo Savernik
 */
class LineIterator
{
protected:
  LinearDocument *lines;	// associated document
  CaretBoxLine *cbl;		// current caret box line

  static CaretBoxIterator currentBox;	// current inline box
  static long currentOffset;

  // Note: cbl == 0 indicates a position beyond the beginning or the
  // end of a document.

  /** Default constructor, only for internal use
   */
  LineIterator() {}

  /** Initializes a new iterator.
   *
   * Note: This constructor neither cares about the correctness of @p node
   * nor about @p offset. It is the responsibility of the caller to ensure
   * that both point to valid places.
   */
  LineIterator(LinearDocument *l, DOM::NodeImpl *node, long offset);

public:
  /** dereferences current caret box line.
   *
   * @returns the caret line box or 0 if end of document
   */
  CaretBoxLine *operator *() const { return cbl; }

  /** returns the associated linear document
   */
  LinearDocument *linearDocument() const { return lines; }

  /** seek next line
   *
   * Guaranteed to crash if beyond beginning/end of document.
   */
  LineIterator &operator ++() { advance(false); return *this; }

  /** seek previous line.
   *
   * Guaranteed to crash if beyond beginning/end of document.
   */
  LineIterator &operator --() { advance(true); return *this; }

  /** compares two iterators. The comparator actually works only for
   * comparing arbitrary iterators to begin() and end().
   */
  bool operator ==(const LineIterator &it) const
  {
    return lines == it.lines && cbl == it.cbl;
  }

  /** compares two iterators
   */
  bool operator !=(const LineIterator &it) const
  {
    return !operator ==(it);
  }

  /** Returns whether this line represents the outside end of the containing
   * block.
   *
   * This result can only be relied on when isOutside is true.
   */
  bool isOutsideEnd() { return cbl->isOutsideEnd(); }

  /** Tells whether the offset is meant to be outside or inside the
   * containing block.
   */
  bool isOutside() const { return cbl->isOutside(); }

  /** advances to the line to come.
   * @param toBegin true, move to previous line, false, move to next line.
   */
  void advance(bool toBegin);

  /** Whenever a new line iterator is created, it gets a caret box created.
   * For memory reasons, it's saved in a static instance,
   * thus making this function not thread-safe.
   *
   * This value can only be trusted immediately after having instantiated
   * a line iterator or one of its derivatives.
   * @return an iterator onto the corresponing caret box within the
   *	line represented by the last instantiation of a line iterator,
   *	or 0 if there was none.
   */
  static CaretBoxIterator &currentCaretBox() { return currentBox; }

  /** Whenever a new line iterator is created, it calculates a modified offset
   * that is to be used with respect to the current render object.
   * This offset can be queried with this function.
   *
   * This value can only be trusted immediately after having instantiated
   * a line iterator or one of its derivatives.
   * @return the modified offset.
   */
  static long currentModifiedOffset() { return currentOffset; }

protected:
  /** seeks next block.
   */
  void nextBlock();
  /** seeks previous block.
   */
  void prevBlock();

  friend class CaretBoxIterator;
  friend class EditableLineIterator;
  friend class EditableCaretBoxIterator;
  friend class EditableCharacterIterator;
  friend class LinearDocument;
};

/**
 * Represents the whole document in terms of lines.
 *
 * SGML documents are trees. But for navigation, this representation is
 * not practical. Therefore this class serves as a helper to represent the
 * document as a linear list of lines. Its usage somewhat resembles STL
 * semantics like begin and end as well as iterators.
 *
 * The lines itself are represented as caret line boxes.
 *
 * LinearDocument instances are not meant to be kept over the lifetime of their
 * associated document, but constructed from (node, offset) pairs whenever line
 * traversal is needed. This is because the underlying InlineFlowBox objects
 * may be destroyed and recreated (e. g. by resizing the window, adding/removing
 * elements).
 *
 * @author Leo Savernik
 * @since 3.2
 * @internal
 */
class LinearDocument {
public:
  typedef LineIterator Iterator;

  /**
   * Creates a new instance, and initializes it to the line specified by
   * the parameters below.
   *
   * Creation will fail if @p node is invisible or defect.
   * @param part part within which everything is taking place.
   * @param node document node with which to start
   * @param offset zero-based offset within this node.
   * @param advancePolicy caret advance policy
   * @param baseElem base element which the caret must not advance beyond
   *	(0 means whole document). The base element will be ignored if it
   *	cannot serve as a base (to see if this is the case, check whether
   *	LinearDocument::baseFlow()->element() != base)
   */
  LinearDocument(KHTMLPart *part, DOM::NodeImpl *node, long offset,
  		CaretAdvancePolicy advancePolicy, DOM::ElementImpl *baseElem);

  virtual ~LinearDocument();

  /**
   * Tells whether this list contains any lines.
   *
   * @returns @p true if this document contains lines, @p false otherwise. Note
   *	that an empty document contains at least one line, so this method
   *	only returns @p false if the document could not be initialised for
   *	some reason.
   */
  bool isValid() const		// FIXME: not yet impl'd
  {
    return true;
  }

  /**
   * Returns the count of lines.
   *
   * Warning: This function is expensive. Call it once and cache the value.
   *
   * FIXME: It's not implemented yet (and maybe never will)
   */
  int count() const;

  /**
   * Returns a line iterator containing the current position as its starting
   * value.
   */
  Iterator current();

  /**
   * Returns a line iterator pointing right after the end of the document.
   */
  const Iterator &end() const { return _end; }

  /**
   * Returns a line iterator pointing to the very last line of the document.
   */
  Iterator preEnd();

  /**
   * Returns a line iterator pointing to the very first line of the document.
   */
  Iterator begin();

  /**
   * Returns a line iterator pointing just before the very first line of the
   * document (this is somewhat an emulation of reverse iterators).
   */
  const Iterator &preBegin() const { return _preBegin; }

  /**
   * Returns the current caret advance policy
   */
  CaretAdvancePolicy advancePolicy() const { return advPol; }

  /**
   * Returns the base render object which the caret must not advance beyond.
   *
   * Note that HTML documents are usually restricted to the body element.
   *
   * @return the base render object or 0 if the whole document is valid.
   */
  RenderObject *baseObject() const { return base; }

protected:
  void initPreBeginIterator();
  void initEndIterator();

protected:
  CaretBoxLineDeleter cblDeleter;	// mass deleter for caret box lines
  DOM::NodeImpl *node;
  long offset;

  Iterator _preBegin;
  Iterator _end;

  KHTMLPart *m_part;
  CaretAdvancePolicy advPol;
  RenderObject *base;

  friend class LineIterator;
  friend class EditableLineIterator;
  friend class ErgonomicEditableLineIterator;
  friend class CaretBoxIterator;