visibleposition.cpp

linux下开源浏览器WebKit的源码,市面上的很多商用浏览器都是移植自WebKit

/*
 * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 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. 
 */

#include "config.h"
#include "VisiblePosition.h"

#include "CString.h"
#include "Document.h"
#include "Element.h"
#include "FloatQuad.h"
#include "HTMLNames.h"
#include "InlineTextBox.h"
#include "Logging.h"
#include "Range.h"
#include "Text.h"
#include "htmlediting.h"
#include "visible_units.h"
#include <stdio.h>

namespace WebCore {

using namespace HTMLNames;

VisiblePosition::VisiblePosition(const Position &pos, EAffinity affinity)
{
    init(pos, affinity);
}

VisiblePosition::VisiblePosition(Node *node, int offset, EAffinity affinity)
{
    ASSERT(offset >= 0);
    init(Position(node, offset), affinity);
}

void VisiblePosition::init(const Position& position, EAffinity affinity)
{
    m_affinity = affinity;
    
    m_deepPosition = canonicalPosition(position);
    
    // When not at a line wrap, make sure to end up with DOWNSTREAM affinity.
    if (m_affinity == UPSTREAM && (isNull() || inSameLine(VisiblePosition(position, DOWNSTREAM), *this)))
        m_affinity = DOWNSTREAM;
}

VisiblePosition VisiblePosition::next(bool stayInEditableContent) const
{
    VisiblePosition next(nextVisuallyDistinctCandidate(m_deepPosition), m_affinity);
    
    if (!stayInEditableContent)
        return next;
    
    return honorEditableBoundaryAtOrAfter(next);
}

VisiblePosition VisiblePosition::previous(bool stayInEditableContent) const
{
    // find first previous DOM position that is visible
    Position pos = previousVisuallyDistinctCandidate(m_deepPosition);
    
    // return null visible position if there is no previous visible position
    if (pos.atStart())
        return VisiblePosition();
        
    VisiblePosition prev = VisiblePosition(pos, DOWNSTREAM);
    ASSERT(prev != *this);
    
#ifndef NDEBUG
    // we should always be able to make the affinity DOWNSTREAM, because going previous from an
    // UPSTREAM position can never yield another UPSTREAM position (unless line wrap length is 0!).
    if (prev.isNotNull() && m_affinity == UPSTREAM) {
        VisiblePosition temp = prev;
        temp.setAffinity(UPSTREAM);
        ASSERT(inSameLine(temp, prev));
    }
#endif

    if (!stayInEditableContent)
        return prev;
    
    return honorEditableBoundaryAtOrBefore(prev);
}

Position VisiblePosition::leftVisuallyDistinctCandidate() const
{
    Position p = m_deepPosition;
    if (!p.node())
        return Position();

    Position downstreamStart = p.downstream();
    TextDirection primaryDirection = LTR;
    for (RenderObject* r = p.node()->renderer(); r; r = r->parent()) {
        if (r->isBlockFlow()) {
            primaryDirection = r->style()->direction();
            break;
        }
    }

    while (true) {
        InlineBox* box;
        int offset;
        p.getInlineBoxAndOffset(m_affinity, primaryDirection, box, offset);
        if (!box)
            return primaryDirection == LTR ? previousVisuallyDistinctCandidate(m_deepPosition) : nextVisuallyDistinctCandidate(m_deepPosition);

        RenderObject* renderer = box->renderer();

        while (true) {
            if ((renderer->isReplaced() || renderer->isBR()) && offset == box->caretRightmostOffset())
                return box->direction() == LTR ? previousVisuallyDistinctCandidate(m_deepPosition) : nextVisuallyDistinctCandidate(m_deepPosition);

            offset = box->direction() == LTR ? renderer->previousOffset(offset) : renderer->nextOffset(offset);

            int caretMinOffset = box->caretMinOffset();
            int caretMaxOffset = box->caretMaxOffset();

            if (offset > caretMinOffset && offset < caretMaxOffset)
                break;

            if (box->direction() == LTR ? offset < caretMinOffset : offset > caretMaxOffset) {
                // Overshot to the left.
                InlineBox* prevBox = box->prevLeafChild();
                if (!prevBox)
                    return primaryDirection == LTR ? previousVisuallyDistinctCandidate(m_deepPosition) : nextVisuallyDistinctCandidate(m_deepPosition);

                // Reposition at the other logical position corresponding to our edge's visual position and go for another round.
                box = prevBox;
                renderer = box->renderer();
                offset = prevBox->caretRightmostOffset();
                continue;
            }

            ASSERT(offset == box->caretLeftmostOffset());

            unsigned char level = box->bidiLevel();
            InlineBox* prevBox = box->prevLeafChild();

            if (box->direction() == primaryDirection) {
                if (!prevBox || prevBox->bidiLevel() >= level)
                    break;

                level = prevBox->bidiLevel();

                InlineBox* nextBox = box;
                do {
                    nextBox = nextBox->nextLeafChild();
                } while (nextBox && nextBox->bidiLevel() > level);

                if (nextBox && nextBox->bidiLevel() == level)
                    break;

                while (InlineBox* prevBox = box->prevLeafChild()) {
                    if (prevBox->bidiLevel() < level)
                        break;
                    box = prevBox;
                }
                renderer = box->renderer();
                offset = box->caretRightmostOffset();
                if (box->direction() == primaryDirection)
                    break;
                continue;
            }

            if (prevBox) {
                box = prevBox;
                renderer = box->renderer();
                offset = box->caretRightmostOffset();
                if (box->bidiLevel() > level) {
                    do {
                        prevBox = box->prevLeafChild();
                    } while (prevBox && prevBox->bidiLevel() > level);

                    if (!prevBox || prevBox->bidiLevel() < level)
                        continue;
                }
            } else {
                // Trailing edge of a secondary run. Set to the leading edge of the entire run.
                while (true) {
                    while (InlineBox* nextBox = box->nextLeafChild()) {
                        if (nextBox->bidiLevel() < level)
                            break;
                        box = nextBox;
                    }
                    if (box->bidiLevel() == level)
                        break;
                    level = box->bidiLevel();
                    while (InlineBox* prevBox = box->prevLeafChild()) {
                        if (prevBox->bidiLevel() < level)
                            break;
                        box = prevBox;
                    }
                    if (box->bidiLevel() == level)
                        break;
                    level = box->bidiLevel();
                }
                renderer = box->renderer();
                offset = primaryDirection == LTR ? box->caretMinOffset() : box->caretMaxOffset();
            }
            break;
        }

        p = Position(renderer->node(), offset);

        if (p.isCandidate() && p.downstream() != downstreamStart || p.atStart() || p.atEnd())
            return p;
    }
}

VisiblePosition VisiblePosition::left(bool stayInEditableContent) const
{
    Position pos = leftVisuallyDistinctCandidate();
    if (pos.atStart() || pos.atEnd())
        return VisiblePosition();

    VisiblePosition left = VisiblePosition(pos, DOWNSTREAM);
    ASSERT(left != *this);

    if (!stayInEditableContent)
        return left;

    // FIXME: This may need to do something different from "before".
    return honorEditableBoundaryAtOrBefore(left);
}

Position VisiblePosition::rightVisuallyDistinctCandidate() const
{
    Position p = m_deepPosition;
    if (!p.node())
        return Position();

    Position downstreamStart = p.downstream();
    TextDirection primaryDirection = LTR;
    for (RenderObject* r = p.node()->renderer(); r; r = r->parent()) {
        if (r->isBlockFlow()) {
            primaryDirection = r->style()->direction();
            break;
        }
    }

    while (true) {
        InlineBox* box;
        int offset;
        p.getInlineBoxAndOffset(m_affinity, primaryDirection, box, offset);
        if (!box)
            return primaryDirection == LTR ? nextVisuallyDistinctCandidate(m_deepPosition) : previousVisuallyDistinctCandidate(m_deepPosition);

        RenderObject* renderer = box->renderer();

        while (true) {
            if ((renderer->isReplaced() || renderer->isBR()) && offset == box->caretLeftmostOffset())
                return box->direction() == LTR ? nextVisuallyDistinctCandidate(m_deepPosition) : previousVisuallyDistinctCandidate(m_deepPosition);

            offset = box->direction() == LTR ? renderer->nextOffset(offset) : renderer->previousOffset(offset);

            int caretMinOffset = box->caretMinOffset();
            int caretMaxOffset = box->caretMaxOffset();

            if (offset > caretMinOffset && offset < caretMaxOffset)
                break;

            if (box->direction() == LTR ? offset > caretMaxOffset : offset < caretMinOffset) {
                // Overshot to the right.
                InlineBox* nextBox = box->nextLeafChild();
                if (!nextBox)
                    return primaryDirection == LTR ? nextVisuallyDistinctCandidate(m_deepPosition) : previousVisuallyDistinctCandidate(m_deepPosition);

                // Reposition at the other logical position corresponding to our edge's visual position and go for another round.
                box = nextBox;
                renderer = box->renderer();
                offset = nextBox->caretLeftmostOffset();
                continue;
            }

            ASSERT(offset == box->caretRightmostOffset());

            unsigned char level = box->bidiLevel();
            InlineBox* nextBox = box->nextLeafChild();

            if (box->direction() == primaryDirection) {
                if (!nextBox || nextBox->bidiLevel() >= level)
                    break;

                level = nextBox->bidiLevel();

                InlineBox* prevBox = box;
                do {
                    prevBox = prevBox->prevLeafChild();
                } while (prevBox && prevBox->bidiLevel() > level);

                if (prevBox && prevBox->bidiLevel() == level)   // For example, abc FED 123 ^ CBA
                    break;

                // For example, abc 123 ^ CBA
                while (InlineBox* nextBox = box->nextLeafChild()) {
                    if (nextBox->bidiLevel() < level)
                        break;
                    box = nextBox;
                }
                renderer = box->renderer();
                offset = box->caretLeftmostOffset();
                if (box->direction() == primaryDirection)
                    break;
                continue;
            }

            if (nextBox) {
                box = nextBox;
                renderer = box->renderer();
                offset = box->caretLeftmostOffset();
                if (box->bidiLevel() > level) {
                    do {
                        nextBox = box->nextLeafChild();
                    } while (nextBox && nextBox->bidiLevel() > level);

                    if (!nextBox || nextBox->bidiLevel() < level)
                        continue;
                }
            } else {
                // Trailing edge of a secondary run. Set to the leading edge of the entire run.
                while (true) {