deleteselectioncommand.cpp

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/*
 * Copyright (C) 2005 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 "DeleteSelectionCommand.h"

#include "Document.h"
#include "DocumentFragment.h"
#include "Editor.h"
#include "EditorClient.h"
#include "Element.h"
#include "Frame.h"
#include "Logging.h"
#include "CSSComputedStyleDeclaration.h"
#include "htmlediting.h"
#include "HTMLInputElement.h"
#include "HTMLNames.h"
#include "markup.h"
#include "RenderTableCell.h"
#include "ReplaceSelectionCommand.h"
#include "Text.h"
#include "TextIterator.h"
#include "visible_units.h"

namespace WebCore {

using namespace HTMLNames;

static bool isTableRow(const Node* node)
{
    return node && node->hasTagName(trTag);
}

static bool isTableCellEmpty(Node* cell)
{
    ASSERT(isTableCell(cell));
    VisiblePosition firstInCell(Position(cell, 0));
    VisiblePosition lastInCell(Position(cell, maxDeepOffset(cell)));
    return firstInCell == lastInCell;
}

static bool isTableRowEmpty(Node* row)
{
    if (!isTableRow(row))
        return false;
        
    for (Node* child = row->firstChild(); child; child = child->nextSibling())
        if (isTableCell(child) && !isTableCellEmpty(child))
            return false;
    
    return true;
}

DeleteSelectionCommand::DeleteSelectionCommand(Document *document, bool smartDelete, bool mergeBlocksAfterDelete, bool replace, bool expandForSpecialElements)
    : CompositeEditCommand(document), 
      m_hasSelectionToDelete(false), 
      m_smartDelete(smartDelete), 
      m_mergeBlocksAfterDelete(mergeBlocksAfterDelete),
      m_replace(replace),
      m_expandForSpecialElements(expandForSpecialElements),
      m_pruneStartBlockIfNecessary(false),
      m_startBlock(0),
      m_endBlock(0),
      m_typingStyle(0),
      m_deleteIntoBlockquoteStyle(0)
{
}

DeleteSelectionCommand::DeleteSelectionCommand(const VisibleSelection& selection, bool smartDelete, bool mergeBlocksAfterDelete, bool replace, bool expandForSpecialElements)
    : CompositeEditCommand(selection.start().node()->document()), 
      m_hasSelectionToDelete(true), 
      m_smartDelete(smartDelete), 
      m_mergeBlocksAfterDelete(mergeBlocksAfterDelete),
      m_replace(replace),
      m_expandForSpecialElements(expandForSpecialElements),
      m_pruneStartBlockIfNecessary(false),
      m_selectionToDelete(selection),
      m_startBlock(0),
      m_endBlock(0),
      m_typingStyle(0),
      m_deleteIntoBlockquoteStyle(0)
{
}

void DeleteSelectionCommand::initializeStartEnd(Position& start, Position& end)
{
    Node* startSpecialContainer = 0;
    Node* endSpecialContainer = 0;
 
    start = m_selectionToDelete.start();
    end = m_selectionToDelete.end();
 
    // For HRs, we'll get a position at (HR,1) when hitting delete from the beginning of the previous line, or (HR,0) when forward deleting,
    // but in these cases, we want to delete it, so manually expand the selection
    if (start.node()->hasTagName(hrTag))
        start = Position(start.node(), 0);
    else if (end.node()->hasTagName(hrTag))
        end = Position(end.node(), 1);
    
    // FIXME: This is only used so that moveParagraphs can avoid the bugs in special element expanion.
    if (!m_expandForSpecialElements)
        return;
    
    while (1) {
        startSpecialContainer = 0;
        endSpecialContainer = 0;
    
        Position s = positionBeforeContainingSpecialElement(start, &startSpecialContainer);
        Position e = positionAfterContainingSpecialElement(end, &endSpecialContainer);
        
        if (!startSpecialContainer && !endSpecialContainer)
            break;
            
        if (VisiblePosition(start) != m_selectionToDelete.visibleStart() || VisiblePosition(end) != m_selectionToDelete.visibleEnd())
            break;
        
        // If we're going to expand to include the startSpecialContainer, it must be fully selected.
        if (startSpecialContainer && !endSpecialContainer && Range::compareBoundaryPoints(positionAfterNode(startSpecialContainer), end) > -1)
            break;

        // If we're going to expand to include the endSpecialContainer, it must be fully selected.         
        if (endSpecialContainer && !startSpecialContainer && Range::compareBoundaryPoints(start, positionBeforeNode(endSpecialContainer)) > -1)
            break;
        
        if (startSpecialContainer && startSpecialContainer->isDescendantOf(endSpecialContainer))
            // Don't adjust the end yet, it is the end of a special element that contains the start
            // special element (which may or may not be fully selected).
            start = s;
        else if (endSpecialContainer && endSpecialContainer->isDescendantOf(startSpecialContainer))
            // Don't adjust the start yet, it is the start of a special element that contains the end
            // special element (which may or may not be fully selected).
            end = e;
        else {
            start = s;
            end = e;
        }
    }
}

void DeleteSelectionCommand::initializePositionData()
{
    Position start, end;
    initializeStartEnd(start, end);
    
    m_upstreamStart = start.upstream();
    m_downstreamStart = start.downstream();
    m_upstreamEnd = end.upstream();
    m_downstreamEnd = end.downstream();
    
    m_startRoot = editableRootForPosition(start);
    m_endRoot = editableRootForPosition(end);
    
    m_startTableRow = enclosingNodeOfType(start, &isTableRow);
    m_endTableRow = enclosingNodeOfType(end, &isTableRow);
    
    // Don't move content out of a table cell.
    // If the cell is non-editable, enclosingNodeOfType won't return it by default, so
    // tell that function that we don't care if it returns non-editable nodes.
    Node* startCell = enclosingNodeOfType(m_upstreamStart, &isTableCell, false);
    Node* endCell = enclosingNodeOfType(m_downstreamEnd, &isTableCell, false);
    // FIXME: This isn't right.  A borderless table with two rows and a single column would appear as two paragraphs.
    if (endCell && endCell != startCell)
        m_mergeBlocksAfterDelete = false;
    
    // Usually the start and the end of the selection to delete are pulled together as a result of the deletion.
    // Sometimes they aren't (like when no merge is requested), so we must choose one position to hold the caret 
    // and receive the placeholder after deletion.
    VisiblePosition visibleEnd(m_downstreamEnd);
    if (m_mergeBlocksAfterDelete && !isEndOfParagraph(visibleEnd))
        m_endingPosition = m_downstreamEnd;
    else
        m_endingPosition = m_downstreamStart;
    
    // We don't want to merge into a block if it will mean changing the quote level of content after deleting 
    // selections that contain a whole number paragraphs plus a line break, since it is unclear to most users 
    // that such a selection actually ends at the start of the next paragraph. This matches TextEdit behavior 
    // for indented paragraphs.
    if (numEnclosingMailBlockquotes(start) != numEnclosingMailBlockquotes(end) && isStartOfParagraph(visibleEnd) && isStartOfParagraph(VisiblePosition(start))) {
        m_mergeBlocksAfterDelete = false;
        m_pruneStartBlockIfNecessary = true;
    }

    // Handle leading and trailing whitespace, as well as smart delete adjustments to the selection
    m_leadingWhitespace = m_upstreamStart.leadingWhitespacePosition(m_selectionToDelete.affinity());
    m_trailingWhitespace = m_downstreamEnd.trailingWhitespacePosition(VP_DEFAULT_AFFINITY);

    if (m_smartDelete) {
    
        // skip smart delete if the selection to delete already starts or ends with whitespace
        Position pos = VisiblePosition(m_upstreamStart, m_selectionToDelete.affinity()).deepEquivalent();
        bool skipSmartDelete = pos.trailingWhitespacePosition(VP_DEFAULT_AFFINITY, true).isNotNull();
        if (!skipSmartDelete)
            skipSmartDelete = m_downstreamEnd.leadingWhitespacePosition(VP_DEFAULT_AFFINITY, true).isNotNull();

        // extend selection upstream if there is whitespace there
        bool hasLeadingWhitespaceBeforeAdjustment = m_upstreamStart.leadingWhitespacePosition(m_selectionToDelete.affinity(), true).isNotNull();
        if (!skipSmartDelete && hasLeadingWhitespaceBeforeAdjustment) {
            VisiblePosition visiblePos = VisiblePosition(m_upstreamStart, VP_DEFAULT_AFFINITY).previous();
            pos = visiblePos.deepEquivalent();
            // Expand out one character upstream for smart delete and recalculate
            // positions based on this change.
            m_upstreamStart = pos.upstream();
            m_downstreamStart = pos.downstream();
            m_leadingWhitespace = m_upstreamStart.leadingWhitespacePosition(visiblePos.affinity());
        }
        
        // trailing whitespace is only considered for smart delete if there is no leading
        // whitespace, as in the case where you double-click the first word of a paragraph.
        if (!skipSmartDelete && !hasLeadingWhitespaceBeforeAdjustment && m_downstreamEnd.trailingWhitespacePosition(VP_DEFAULT_AFFINITY, true).isNotNull()) {
            // Expand out one character downstream for smart delete and recalculate
            // positions based on this change.
            pos = VisiblePosition(m_downstreamEnd, VP_DEFAULT_AFFINITY).next().deepEquivalent();
            m_upstreamEnd = pos.upstream();
            m_downstreamEnd = pos.downstream();
            m_trailingWhitespace = m_downstreamEnd.trailingWhitespacePosition(VP_DEFAULT_AFFINITY);
        }
    }
    
    // We must pass the positions through rangeCompliantEquivalent, since some editing positions
    // that appear inside their nodes aren't really inside them.  [hr, 0] is one example.
    // FIXME: rangeComplaintEquivalent should eventually be moved into enclosing element getters
    // like the one below, since editing functions should obviously accept editing positions.
    // FIXME: Passing false to enclosingNodeOfType tells it that it's OK to return a non-editable
    // node.  This was done to match existing behavior, but it seems wrong.
    m_startBlock = enclosingNodeOfType(rangeCompliantEquivalent(m_downstreamStart), &isBlock, false);
    m_endBlock = enclosingNodeOfType(rangeCompliantEquivalent(m_upstreamEnd), &isBlock, false);
}

static void removeEnclosingAnchorStyle(CSSMutableStyleDeclaration* style, const Position& position)
{
    Node* enclosingAnchor = enclosingAnchorElement(position);
    if (!enclosingAnchor || !enclosingAnchor->parentNode())
        return;
            
    RefPtr<CSSMutableStyleDeclaration> parentStyle = Position(enclosingAnchor->parentNode(), 0).computedStyle()->copyInheritableProperties();
    RefPtr<CSSMutableStyleDeclaration> anchorStyle = Position(enclosingAnchor, 0).computedStyle()->copyInheritableProperties();
    parentStyle->diff(anchorStyle.get());
    anchorStyle->diff(style);
}

void DeleteSelectionCommand::saveTypingStyleState()
{
    // A common case is deleting characters that are all from the same text node. In 
    // that case, the style at the start of the selection before deletion will be the 
    // same as the style at the start of the selection after deletion (since those
    // two positions will be identical). Therefore there is no need to save the