dom_position.cpp

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/*
 * Copyright (C) 2004 Apple Computer, 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 "dom_position.h"

#include <qstring.h>

#include "css_computedstyle.h"
#include "css_valueimpl.h"
#include "dom_elementimpl.h"
#include "dom_nodeimpl.h"
#include "dom_positioniterator.h"
#include "dom2_range.h"
#include "dom2_rangeimpl.h"
#include "dom2_viewsimpl.h"
#include "helper.h"
#include "htmltags.h"
#include "text_affinity.h"
#include "visible_position.h"
#include "rendering/render_block.h"
#include "rendering/render_flow.h"
#include "rendering/render_line.h"
#include "rendering/render_style.h"
#include "rendering/render_text.h"
#include "editing/visible_text.h"

#if APPLE_CHANGES
#include "KWQAssertions.h"
#include "KWQLogging.h"
#else
#define ASSERT(assertion) assert(assertion)
#define LOG(channel, formatAndArgs...) ((void)0)
#endif

using khtml::EAffinity;
using khtml::InlineBox;
using khtml::InlineTextBox;
using khtml::isCollapsibleWhitespace;
using khtml::RenderBlock;
using khtml::RenderFlow;
using khtml::RenderObject;
using khtml::RenderText;
using khtml::RootInlineBox;
using khtml::VISIBLE;
using khtml::VisiblePosition;

namespace DOM {

static NodeImpl *nextRenderedEditable(NodeImpl *node)
{
    while (1) {
        node = node->nextEditable();
        if (!node)
            return 0;
        if (!node->renderer())
            continue;
        if (node->renderer()->inlineBox(0))
            return node;
    }
    return 0;
}

static NodeImpl *previousRenderedEditable(NodeImpl *node)
{
    while (1) {
        node = node->previousEditable();
        if (!node)
            return 0;
        if (!node->renderer())
            continue;
        if (node->renderer()->inlineBox(0))
            return node;
    }
    return 0;
}


Position::Position(NodeImpl *node, long offset) 
    : m_node(node), m_offset(offset) 
{ 
    if (node) {
        node->ref();
    }
}

Position::Position(const Position &o)
    : m_node(o.m_node), m_offset(o.m_offset) 
{
    if (m_node) {
        m_node->ref();
    }
}

Position::~Position()
{
    if (m_node) {
        m_node->deref();
    }
}

Position &Position::operator=(const Position &o)
{
    if (m_node) {
        m_node->deref();
    }
    m_node = o.m_node;
    if (m_node) {
        m_node->ref();
    }

    m_offset = o.m_offset;
    
    return *this;
}

void Position::clear()
{
    if (m_node) {
        m_node->deref();
        m_node = 0;
    }
    m_offset = 0;
}

ElementImpl *Position::element() const
{
    NodeImpl *n;
    for (n = node(); n && !n->isElementNode(); n = n->parentNode())
        ; // empty loop body
    return static_cast<ElementImpl *>(n);
}

CSSComputedStyleDeclarationImpl *Position::computedStyle() const
{
    ElementImpl *elem = element();
    if (!elem)
        return 0;
    return new CSSComputedStyleDeclarationImpl(elem);
}

long Position::renderedOffset() const
{
    if (!node()->isTextNode())
        return offset();
   
    if (!node()->renderer())
        return offset();
                    
    long result = 0;
    RenderText *textRenderer = static_cast<RenderText *>(node()->renderer());
    for (InlineTextBox *box = textRenderer->firstTextBox(); box; box = box->nextTextBox()) {
        long start = box->m_start;
        long end = box->m_start + box->m_len;
        if (offset() < start)
            return result;
        if (offset() <= end) {
            result += offset() - start;
            return result;
        }
        result += box->m_len;
    }
    return result;
}

Position Position::previousCharacterPosition(EAffinity affinity) const
{
    if (isNull())
        return Position();

    NodeImpl *fromRootEditableElement = node()->rootEditableElement();
    PositionIterator it(*this);

    bool atStartOfLine = isFirstVisiblePositionOnLine(VisiblePosition(*this, affinity));
    bool rendered = inRenderedContent();
    
    while (!it.atStart()) {
        Position pos = it.previous();

        if (pos.node()->rootEditableElement() != fromRootEditableElement)
            return *this;

        if (atStartOfLine || !rendered) {
            if (pos.inRenderedContent())
                return pos;
        }
        else if (rendersInDifferentPosition(pos))
            return pos;
    }
    
    return *this;
}

Position Position::nextCharacterPosition(EAffinity affinity) const
{
    if (isNull())
        return Position();

    NodeImpl *fromRootEditableElement = node()->rootEditableElement();
    PositionIterator it(*this);

    bool atEndOfLine = isLastVisiblePositionOnLine(VisiblePosition(*this, affinity));
    bool rendered = inRenderedContent();
    
    while (!it.atEnd()) {
        Position pos = it.next();

        if (pos.node()->rootEditableElement() != fromRootEditableElement)
            return *this;

        if (atEndOfLine || !rendered) {
            if (pos.inRenderedContent())
                return pos;
        }
        else if (rendersInDifferentPosition(pos))
            return pos;
    }
    
    return *this;
}

Position Position::upstream(EStayInBlock stayInBlock) const
{
    Position start = equivalentDeepPosition();
    NodeImpl *startNode = start.node();
    if (!startNode)
        return Position();

    NodeImpl *block = startNode->enclosingBlockFlowOrTableElement();
    Position lastVisible;
    
    PositionIterator it(start);
    for (; !it.atStart(); it.previous()) {
        NodeImpl *currentNode = it.current().node();

        if (stayInBlock) {
            NodeImpl *currentBlock = currentNode->enclosingBlockFlowOrTableElement();
            if (block != currentBlock)
                return it.next();
        }

        RenderObject *renderer = currentNode->renderer();
        if (!renderer)
            continue;

        if (renderer->style()->visibility() != VISIBLE)
            continue;

        lastVisible = it.current();

        if (renderer->isReplaced() || renderer->isBR()) {
            if (it.current().offset() >= renderer->caretMaxOffset())
                return Position(currentNode, renderer->caretMaxOffset());
            else
                continue;
        }

        if (renderer->isText() && static_cast<RenderText *>(renderer)->firstTextBox()) {
            if (currentNode != startNode)
                return Position(currentNode, renderer->caretMaxOffset());

            if (it.current().offset() < 0)
                continue;
            uint textOffset = it.current().offset();

            RenderText *textRenderer = static_cast<RenderText *>(renderer);
            for (InlineTextBox *box = textRenderer->firstTextBox(); box; box = box->nextTextBox()) {
                if (textOffset > box->start() && textOffset <= box->start() + box->len())
                    return it.current();
                else if (box != textRenderer->lastTextBox() && 
                         !box->nextOnLine() && 
                         textOffset == box->start() + box->len() + 1)
                    return it.current();
            }
        }
    }
    
    return lastVisible.isNotNull() ? lastVisible : *this;
}

Position Position::downstream(EStayInBlock stayInBlock) const
{
    Position start = equivalentDeepPosition();
    NodeImpl *startNode = start.node();
    if (!startNode)
        return Position();

    NodeImpl *block = startNode->enclosingBlockFlowOrTableElement();
    Position lastVisible;
    
    PositionIterator it(start);            
    for (; !it.atEnd(); it.next()) {   
        NodeImpl *currentNode = it.current().node();

        if (stayInBlock) {
            NodeImpl *currentBlock = currentNode->enclosingBlockFlowOrTableElement();
            if (block != currentBlock)
                return it.previous();
        }

        RenderObject *renderer = currentNode->renderer();
        if (!renderer)
            continue;

        if (renderer->style()->visibility() != VISIBLE)
            continue;

        lastVisible = it.current();

        if (currentNode != startNode && renderer->isBlockFlow()) {
            if (it.current().offset() == 0) {
                // If no first child, or first visible child is a not a block, return; otherwise continue.
                if (!currentNode->firstChild())
                    return Position(currentNode, 0);
                for (NodeImpl *child = currentNode->firstChild(); child; child = child->nextSibling()) {
                    RenderObject *r = child->renderer();
                    if (r && r->style()->visibility() == VISIBLE) {
                         if (r->isBlockFlow())
                            break; // break causes continue code below to run.
                         else
                            return Position(child, 0);
                    }
                }
                continue;
            }
        }

        if (renderer->isReplaced() || renderer->isBR()) {
            if (it.current().offset() <= renderer->caretMinOffset())
                return Position(currentNode, renderer->caretMinOffset());
            else
                continue;
        }

        if (renderer->isText() && static_cast<RenderText *>(renderer)->firstTextBox()) {
            if (currentNode != start.node())
                return Position(currentNode, renderer->caretMinOffset());

            if (it.current().offset() < 0)
                continue;
            uint textOffset = it.current().offset();

            RenderText *textRenderer = static_cast<RenderText *>(renderer);
            for (InlineTextBox *box = textRenderer->firstTextBox(); box; box = box->nextTextBox()) {