khtml_caret_p.h

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/* This file is part of the KDE project
 *
 * Copyright (C) 2003-2004 Leo Savernik <[e-mail]>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#ifndef KHTML_CARET_P_H
#define KHTML_CARET_P_H

#include "rendering/render_table.h"

#include <qvaluevector.h>

#define DEBUG_CARETMODE 0

class QFontMetrics;

namespace DOM {
  class NodeImpl;
  class ElementImpl;
}

namespace khtml {

/** caret advance policy.
 *
 * Used to determine which elements are taken into account when the caret is
 * advanced. Later policies pose refinements of all former
 * policies.
 * @param LeafsOnly advance from leave render object to leaf render object
 *	(It will allow outside flow positions if a flow wouldn't be reachable
 *	otherwise).
 * @param IndicatedFlows place caret also at the beginning/end of flows
 *	that have at least one visible border at any side.
 *	(It will allow not indicated flow positions if a flow wouldn't
 *	be reachable otherwise).
 * @param VisibleFlows place caret also at the beginning/end of any flow
 *	that has a renderer.
 */
enum CaretAdvancePolicy {
    LeafsOnly, IndicatedFlows, VisibleFlows
};

/** contextual information about the caret which is related to the view.
 * An object of this class is only instantiated when it is needed.
 */
struct CaretViewContext {
    int freqTimerId;		// caret blink frequency timer id
    int x, y;			// caret position in viewport coordinates
    				// (y specifies the top, not the baseline)
    int width;			// width of caret in pixels
    int height;			// height of caret in pixels
    bool visible;		// true if currently visible.
    bool displayed;		// true if caret is to be displayed at all.
    bool caretMoved;		// set to true once caret has been moved in page
    				// how to display the caret when view is not focused
    KHTMLPart::CaretDisplayPolicy displayNonFocused;

    /** For natural traversal of lines, the original x position is saved, and
     * the actual x is set to the first character whose x position is
     * greater than origX.
     *
     * origX is reset to x whenever the caret is moved horizontally or placed
     * by the mouse.
     */
    int origX;

    bool keyReleasePending;	// true if keypress under caret mode awaits
    				// corresponding release event
    CaretViewContext() : freqTimerId(-1), x(0), y(0), width(1), height(16),
    	visible(true), displayed(false), caretMoved(false),
	displayNonFocused(KHTMLPart::CaretInvisible), origX(0),
	keyReleasePending(false)
    {}
};

/** contextual information about the editing state.
 * An object of this class is only instantiated when it is needed.
 */
struct EditorContext {
    bool override;		// true if typed characters should override
    				// the existing ones.

    EditorContext() : override(false)
    {}
};

class LinearDocument;

/**
 * Stores objects of a certain type, and calls delete on each of them
 * when this data structure is destroyed.
 *
 * As this structure merely consists of a vector of pointers, all objects
 * allocated can be traversed as seen fit.
 *
 * @author Leo Savernik
 * @since 3.3
 * @internal
 */
template<class T> class MassDeleter : public QValueVector<T *> {
public:
  MassDeleter(size_t reserved = 1) { this->reserve(reserved); }
  ~MassDeleter()
  {
    typename QValueVector<T *>::Iterator nd = this->end();
    for (typename QValueVector<T *>::Iterator it = this->begin(); it != nd; ++it)
      delete *it;
  }
};

class CaretBoxLine;

/**
 * Represents a rectangular box within which the caret is located.
 *
 * The caret box serves as a wrapper for inline boxes of all kind. It either
 * wraps an InlineBox, InlineTextBox, or InlineFlowBox, or if no such boxes
 * exist for a certain context, it contains the relevant information directly.
 *
 * This class will be constructed whenever a caret position has to be described.
 * @since 3.3
 * @author Leo Savernik
 * @internal
 */
class CaretBox {
protected:
  InlineBox *_box;		// associated inline box if available.
  short _w;			// width of box in pixels
  int _h;			// height of box in pixels
  int _x;			// x coordinate relative to containing block
  int _y;			// y coordinate relative to containing block
  RenderBox *cb;		// containing block
  bool _outside:1;		// true when representing the outside of the element
  bool outside_end:1;		// at ending outside of element rather than at beginning
  // 29 bits unused

public:
  /** empty constructor for later assignment */
  CaretBox() {}
  /** initializes the caret box from the given inline box */
  CaretBox(InlineBox *ibox, bool outside, bool outsideEnd) : _box(ibox),
  	_w((short)ibox->width()), _h(ibox->height()), _x(ibox->xPos()),
        _y(ibox->yPos()), cb(0), _outside(outside), outside_end(outsideEnd)
  {
    RenderObject *r = ibox->object();
    if (r) cb = r->containingBlock();
  }
  /** initializes the caret box from scratch */
  CaretBox(int x, int y, int w, int h, RenderBox *cb, bool outside, bool outsideEnd) :
         _box(0), _w((short)w), _h(h), _x(x), _y(y), cb(cb), _outside(outside),
         outside_end(outsideEnd)
  {}

  int width() const { return _w; }
  int height() const { return _h; }
  int xPos() const { return _x; }
  int yPos() const { return _y; }
  RenderBox *enclosingObject() const { return cb; }
  InlineBox *inlineBox() const { return _box; }

  /** returns the containing block of this caret box. If the caret box
   * resembles a block itself, its containing block is returned.
   */
  RenderBlock *containingBlock() const { return _box ? static_cast<RenderBlock *>(cb) : cb->containingBlock(); }

  /** returns the replaced render object if this caret box represents one,
   * 0 otherwise.
   */


  /** returns true if this caret box represents an inline element, or text box,
   * otherwise false.
   */
  bool isInline() const { return _box; }
  /** returns true if this caret box represents an inline text box.
   */
  bool isInlineTextBox() const { return _box && _box->isInlineTextBox(); }
  /** returns true if this caret box represents a line break
   */
  bool isLineBreak() const
  {
    return _box && _box->object() && _box->object()->isBR();
  }
  /** returns true when this caret box represents an ouside position of an
   * element.
   */
  bool isOutside() const { return _outside; }
  /** returns the position at which the outside is targeted at.
   *
   * This method's return value is meaningless if isOutside() is not true.
   * @return true if the outside end is meant, false if the outside beginning
   *	is meant.
   */
  bool isOutsideEnd() const { return outside_end; }
  /** returns the associated render object. */
  RenderObject *object() const { return _box ? _box->object() : cb; }

  /** returns the minimum offset for this caret box.
   */
  long minOffset() const { return _box && !isLineBreak() ? _box->minOffset() : 0; }
  /** returns the maximum offset for this caret box.
   */
  long maxOffset() const { return _box && !isLineBreak() ? _box->maxOffset() : 0; }

#if DEBUG_CARETMODE > 0
  void dump(QTextStream &ts, const QString &ind) const;
#endif

  friend class CaretBoxLine;
};

typedef MassDeleter<CaretBox> CaretBoxDeleter;

/**
 * Iterates over the elements of a caret box line.
 *
 * @author Leo Savernik
 * @internal
 * @since 3.3
 */
class CaretBoxIterator {
protected:
  CaretBoxLine *cbl;		// associated caret box line
  int index;			// current index

public:
  // Let standard constructor/copy constructor/destructor/assignment operator
  // be defined by the compiler. They do exactly what we want.

  bool operator ==(const CaretBoxIterator &it) const
  {
    return cbl == it.cbl && index == it.index;
  }

  bool operator !=(const CaretBoxIterator &it) const
  {
    return !operator ==(it);
  }

  /** returns the current caret box.
   * @return current caret box
   */
  CaretBox *data() const;
  /** shortcut for \c data
   * @return current caret box
   */
  CaretBox *operator *() const { return data(); }

  /** increments the iterator to point to the next caret box.
   */
  CaretBoxIterator &operator ++() { index++; return *this; }
  /** decrements the iterator to point to the previous caret box.
   */
  CaretBoxIterator &operator --() { index--; return *this; }

  friend class CaretBoxLine;
  friend class EditableCaretBoxIterator;
};

/**
 * Resembles a line consisting of caret boxes.
 *
 * To the contrary of InlineFlowBoxes which are nested as needed to map the
 * DOM to the rendered representation, it is sufficient for caret navigation
 * to provide a linear list of unnested caret boxes.
 *
 * \code
 * Example: The document fragment <p>a <i><b>c</b> f</i> g</p> will be
 * represented by three caret box lines which each one consists of caret boxes
 * as follows:
 * CaretBoxLine 1:
 *   CaretBox(cb=<p>, _box=0, _outside=true, outside_end=false)
 * CaretBoxLine 2:
 *   CaretBox(cb=<p>, _box=InlineTextBox("a "), _outside=false)
 *   CaretBox(cb=<p>, _box=InlineFlowBox(<i>), _outside=true, outside_end=false)
 *   CaretBox(cb=<p>, _box=InlineFlowBox(<b>), _outside=true, outside_end=false)
 *   CaretBox(cb=<p>, _box=InlineTextBox("c"), _outside=false)
 *   CaretBox(cb=<p>, _box=InlineFlowBox(<b>), _outside=true, outside_end=true)
 *   CaretBox(cb=<p>, _box=InlineTextBox(" f"), _outside=false)
 *   CaretBox(cb=<p>, _box=InlineFlowBox(<i>), _outside=true, outside_end=true)
 *   CaretBox(cb=<p>, _box=InlineTextBox(" g"), _outside=true, outside_end=true)
 * CaretBoxLine 3:
 *   CaretBox(cb=<p>, _box=0, _outside=true, outside_end=true)
 * \endcode
 */
class CaretBoxLine {
protected:
  CaretBoxDeleter caret_boxes;
  // base flow box which caret boxes have been constructed for
  InlineFlowBox *basefb;

  CaretBoxLine() : caret_boxes(8), basefb(0) {}
  CaretBoxLine(InlineFlowBox *basefb) : caret_boxes(8), basefb(basefb) {}
public:
#if DEBUG_CARETMODE > 3
  ~CaretBoxLine() { kdDebug(6200) << k_funcinfo << "called" << endl; }
#endif

  CaretBoxIterator begin()
  {
    CaretBoxIterator it;
    it.cbl = this;
    it.index = 0;
    return it;
  }
  CaretBoxIterator end()
  {
    CaretBoxIterator it;
    it.cbl = this;
    it.index = caret_boxes.size();
    return it;
  }
  CaretBoxIterator preBegin()
  {
    CaretBoxIterator it;
    it.cbl = this;
    it.index = -1;
    return it;
  }
  CaretBoxIterator preEnd()
  {
    CaretBoxIterator it;
    it.cbl = this;
    it.index = caret_boxes.size() - 1;
    return it;
  }

  /** returns the base inline flow box which the caret boxes of this
   * caret box line have been constructed from.
   *
   * This is generally a root line box, but may be an inline flow box when the
   * base is restricted to an inline element.
   */
  InlineFlowBox *baseFlowBox() const { return basefb; }

  /** returns the containing block */
  RenderBlock *containingBlock() const { return caret_boxes[0]->containingBlock(); }
  /** returns the enclosing object */
  RenderBox *enclosingObject() const { return caret_boxes[0]->enclosingObject(); }

  /** returns whether this caret box line is outside.
   * @return true if this caret box represents an outside position of this
   *	line box' containing block, false otherwise.
   */
  bool isOutside() const
  {
    const CaretBox *cbox = caret_boxes[0];
    return !cbox->isInline() && cbox->isOutside();
  }

  /** returns whether this caret box line is at the outside end.
   *
   * The result cannot be relied upon unless isOutside() returns true.
   */
  bool isOutsideEnd() const { return caret_boxes[0]->isOutsideEnd(); }