visibleselection.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 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 "config.h"
#include "VisibleSelection.h"

#include "CharacterNames.h"
#include "CString.h"
#include "Document.h"
#include "Element.h"
#include "htmlediting.h"
#include "TextIterator.h"
#include "VisiblePosition.h"
#include "visible_units.h"
#include "Range.h"

#include <wtf/Assertions.h>
#include <stdio.h>

namespace WebCore {

VisibleSelection::VisibleSelection()
    : m_affinity(DOWNSTREAM)
    , m_granularity(CharacterGranularity)
    , m_selectionType(NoSelection)
    , m_baseIsFirst(true)
{
}

VisibleSelection::VisibleSelection(const Position& pos, EAffinity affinity)
    : m_base(pos)
    , m_extent(pos)
    , m_affinity(affinity)
    , m_granularity(CharacterGranularity)
{
    validate();
}

VisibleSelection::VisibleSelection(const Position& base, const Position& extent, EAffinity affinity)
    : m_base(base)
    , m_extent(extent)
    , m_affinity(affinity)
    , m_granularity(CharacterGranularity)
{
    validate();
}

VisibleSelection::VisibleSelection(const VisiblePosition& pos)
    : m_base(pos.deepEquivalent())
    , m_extent(pos.deepEquivalent())
    , m_affinity(pos.affinity())
    , m_granularity(CharacterGranularity)
{
    validate();
}

VisibleSelection::VisibleSelection(const VisiblePosition& base, const VisiblePosition& extent)
    : m_base(base.deepEquivalent())
    , m_extent(extent.deepEquivalent())
    , m_affinity(base.affinity())
    , m_granularity(CharacterGranularity)
{
    validate();
}

VisibleSelection::VisibleSelection(const Range* range, EAffinity affinity)
    : m_base(range->startPosition())
    , m_extent(range->endPosition())
    , m_affinity(affinity)
    , m_granularity(CharacterGranularity)
{
    validate();
}

VisibleSelection VisibleSelection::selectionFromContentsOfNode(Node* node)
{
    return VisibleSelection(Position(node, 0), Position(node, maxDeepOffset(node)), DOWNSTREAM);
}

void VisibleSelection::setBase(const Position& position)
{
    m_base = position;
    validate();
}

void VisibleSelection::setBase(const VisiblePosition& visiblePosition)
{
    m_base = visiblePosition.deepEquivalent();
    validate();
}

void VisibleSelection::setExtent(const Position& position)
{
    m_extent = position;
    validate();
}

void VisibleSelection::setExtent(const VisiblePosition& visiblePosition)
{
    m_extent = visiblePosition.deepEquivalent();
    validate();
}

PassRefPtr<Range> VisibleSelection::firstRange() const
{
    if (isNone())
        return 0;
    Position start = rangeCompliantEquivalent(m_start);
    Position end = rangeCompliantEquivalent(m_end);
    return Range::create(start.node()->document(), start, end);
}

PassRefPtr<Range> VisibleSelection::toNormalizedRange() const
{
    if (isNone())
        return 0;

    // Make sure we have an updated layout since this function is called
    // in the course of running edit commands which modify the DOM.
    // Failing to call this can result in equivalentXXXPosition calls returning
    // incorrect results.
    m_start.node()->document()->updateLayout();

    // Check again, because updating layout can clear the selection.
    if (isNone())
        return 0;

    Position s, e;
    if (isCaret()) {
        // If the selection is a caret, move the range start upstream. This helps us match
        // the conventions of text editors tested, which make style determinations based
        // on the character before the caret, if any. 
        s = rangeCompliantEquivalent(m_start.upstream());
        e = s;
    } else {
        // If the selection is a range, select the minimum range that encompasses the selection.
        // Again, this is to match the conventions of text editors tested, which make style 
        // determinations based on the first character of the selection. 
        // For instance, this operation helps to make sure that the "X" selected below is the 
        // only thing selected. The range should not be allowed to "leak" out to the end of the 
        // previous text node, or to the beginning of the next text node, each of which has a 
        // different style.
        // 
        // On a treasure map, <b>X</b> marks the spot.
        //                       ^ selected
        //
        ASSERT(isRange());
        s = m_start.downstream();
        e = m_end.upstream();
        if (Range::compareBoundaryPoints(s.node(), s.offset(), e.node(), e.offset()) > 0) {
            // Make sure the start is before the end.
            // The end can wind up before the start if collapsed whitespace is the only thing selected.
            Position tmp = s;
            s = e;
            e = tmp;
        }
        s = rangeCompliantEquivalent(s);
        e = rangeCompliantEquivalent(e);
    }

    // VisibleSelections are supposed to always be valid.  This constructor will ASSERT
    // if a valid range could not be created, which is fine for this callsite.
    return Range::create(s.node()->document(), s, e);
}

bool VisibleSelection::expandUsingGranularity(TextGranularity granularity)
{
    if (isNone())
        return false;

    m_granularity = granularity;
    validate();
    return true;
}

static PassRefPtr<Range> makeSearchRange(const Position& pos)
{
    Node* n = pos.node();
    if (!n)
        return 0;
    Document* d = n->document();
    Node* de = d->documentElement();
    if (!de)
        return 0;
    Node* boundary = n->enclosingBlockFlowElement();
    if (!boundary)
        return 0;

    RefPtr<Range> searchRange(Range::create(d));
    ExceptionCode ec = 0;

    Position start(rangeCompliantEquivalent(pos));
    searchRange->selectNodeContents(boundary, ec);
    searchRange->setStart(start.node(), start.offset(), ec);

    ASSERT(!ec);
    if (ec)
        return 0;

    return searchRange.release();
}

void VisibleSelection::appendTrailingWhitespace()
{
    RefPtr<Range> searchRange = makeSearchRange(m_end);
    if (!searchRange)
        return;

    CharacterIterator charIt(searchRange.get(), true);

    for (; charIt.length(); charIt.advance(1)) {
        UChar c = charIt.characters()[0];
        if (!isSpaceOrNewline(c) && c != noBreakSpace)
            break;
        m_end = charIt.range()->endPosition();
    }
}

void VisibleSelection::setBaseAndExtentToDeepEquivalents()
{
    // Move the selection to rendered positions, if possible.
    bool baseAndExtentEqual = m_base == m_extent;
    if (m_base.isNotNull()) {
        m_base = VisiblePosition(m_base, m_affinity).deepEquivalent();
        if (baseAndExtentEqual)
            m_extent = m_base;
    }
    if (m_extent.isNotNull() && !baseAndExtentEqual)
        m_extent = VisiblePosition(m_extent, m_affinity).deepEquivalent();

    // Make sure we do not have a dangling base or extent.
    if (m_base.isNull() && m_extent.isNull())
        m_baseIsFirst = true;
    else if (m_base.isNull()) {
        m_base = m_extent;
        m_baseIsFirst = true;
    } else if (m_extent.isNull()) {
        m_extent = m_base;
        m_baseIsFirst = true;
    } else
        m_baseIsFirst = comparePositions(m_base, m_extent) <= 0;
}

void VisibleSelection::setStartAndEndFromBaseAndExtentRespectingGranularity()
{
    if (m_baseIsFirst) {
        m_start = m_base;
        m_end = m_extent;
    } else {
        m_start = m_extent;
        m_end = m_base;
    }

    switch (m_granularity) {
        case CharacterGranularity:
            // Don't do any expansion.
            break;
        case WordGranularity: {
            // General case: Select the word the caret is positioned inside of, or at the start of (RightWordIfOnBoundary).
            // Edge case: If the caret is after the last word in a soft-wrapped line or the last word in
            // the document, select that last word (LeftWordIfOnBoundary).
            // Edge case: If the caret is after the last word in a paragraph, select from the the end of the
            // last word to the line break (also RightWordIfOnBoundary);
            VisiblePosition start = VisiblePosition(m_start, m_affinity);
            VisiblePosition originalEnd(m_end, m_affinity);
            EWordSide side = RightWordIfOnBoundary;
            if (isEndOfDocument(start) || (isEndOfLine(start) && !isStartOfLine(start) && !isEndOfParagraph(start)))
                side = LeftWordIfOnBoundary;
            m_start = startOfWord(start, side).deepEquivalent();
            side = RightWordIfOnBoundary;
            if (isEndOfDocument(originalEnd) || (isEndOfLine(originalEnd) && !isStartOfLine(originalEnd) && !isEndOfParagraph(originalEnd)))
                side = LeftWordIfOnBoundary;
                
            VisiblePosition wordEnd(endOfWord(originalEnd, side));
            VisiblePosition end(wordEnd);
            
            if (isEndOfParagraph(originalEnd)) {
                // Select the paragraph break (the space from the end of a paragraph to the start of 
                // the next one) to match TextEdit.
                end = wordEnd.next();
                
                if (Node* table = isFirstPositionAfterTable(end)) {
                    // The paragraph break after the last paragraph in the last cell of a block table ends
                    // at the start of the paragraph after the table.
                    if (isBlock(table))
                        end = end.next(true);
                    else
                        end = wordEnd;
                }
                
                if (end.isNull())
                    end = wordEnd;
                    
            }
                
            m_end = end.deepEquivalent();
            break;
        }
        case SentenceGranularity: {
            m_start = startOfSentence(VisiblePosition(m_start, m_affinity)).deepEquivalent();
            m_end = endOfSentence(VisiblePosition(m_end, m_affinity)).deepEquivalent();
            break;
        }
        case LineGranularity: {
            m_start = startOfLine(VisiblePosition(m_start, m_affinity)).deepEquivalent();