Source/core/editing/CompositeEditCommand.cpp

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
create
m_editAction
belongsTo
unapply
reapply
append
setStartingSelection
setEndingSelection
apply
ensureComposition
preservesTypingStyle
isTypingCommand
setShouldRetainAutocorrectionIndicator
applyCommandToComposite
applyCommandToComposite
applyStyle
applyStyle
applyStyledElement
removeStyledElement
insertParagraphSeparator
isRemovableBlock
insertNodeBefore
insertNodeAfter
insertNodeAt
appendNode
removeChildrenInRange
removeNode
removeNodePreservingChildren
removeNodeAndPruneAncestors
moveRemainingSiblingsToNewParent
updatePositionForNodeRemovalPreservingChildren
replaceElementWithSpanPreservingChildrenAndAttributes
prune
splitTextNode
splitElement
mergeIdenticalElements
wrapContentsInDummySpan
splitTextNodeContainingElement
insertTextIntoNode
deleteTextFromNode
replaceTextInNode
replaceSelectedTextInNode
copyMarkers
replaceTextInNodePreservingMarkers
positionOutsideTabSpan
insertNodeAtTabSpanPosition
deleteSelection
deleteSelection
removeCSSProperty
removeNodeAttribute
setNodeAttribute
containsOnlyWhitespace
shouldRebalanceLeadingWhitespaceFor
canRebalance
rebalanceWhitespaceAt
rebalanceWhitespaceOnTextSubstring
prepareWhitespaceAtPositionForSplit
replaceCollapsibleWhitespaceWithNonBreakingSpaceIfNeeded
rebalanceWhitespace
deleteInsignificantText
deleteInsignificantText
deleteInsignificantTextDownstream
appendBlockPlaceholder
insertBlockPlaceholder
addBlockPlaceholderIfNeeded
removePlaceholderAt
insertNewDefaultParagraphElementAt
moveParagraphContentsToNewBlockIfNecessary
pushAnchorElementDown
cloneParagraphUnderNewElement
cleanupAfterDeletion
moveParagraphWithClones
moveParagraph
moveParagraphs
breakOutOfEmptyListItem
breakOutOfEmptyMailBlockquotedParagraph
positionAvoidingSpecialElementBoundary
splitTreeToNode
createBlockPlaceholderElement
/*
 * Copyright (C) 2005, 2006, 2007, 2008 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 "core/editing/CompositeEditCommand.h"

#include "HTMLNames.h"
#include "bindings/v8/ExceptionStatePlaceholder.h"
#include "core/dom/Document.h"
#include "core/dom/DocumentFragment.h"
#include "core/dom/DocumentMarkerController.h"
#include "core/dom/ElementTraversal.h"
#include "core/dom/NodeTraversal.h"
#include "core/dom/Range.h"
#include "core/dom/Text.h"
#include "core/editing/AppendNodeCommand.h"
#include "core/editing/ApplyStyleCommand.h"
#include "core/editing/DeleteFromTextNodeCommand.h"
#include "core/editing/DeleteSelectionCommand.h"
#include "core/editing/Editor.h"
#include "core/editing/InsertIntoTextNodeCommand.h"
#include "core/editing/InsertLineBreakCommand.h"
#include "core/editing/InsertNodeBeforeCommand.h"
#include "core/editing/InsertParagraphSeparatorCommand.h"
#include "core/editing/MergeIdenticalElementsCommand.h"
#include "core/editing/PlainTextRange.h"
#include "core/editing/RemoveCSSPropertyCommand.h"
#include "core/editing/RemoveNodeCommand.h"
#include "core/editing/RemoveNodePreservingChildrenCommand.h"
#include "core/editing/ReplaceNodeWithSpanCommand.h"
#include "core/editing/ReplaceSelectionCommand.h"
#include "core/editing/SetNodeAttributeCommand.h"
#include "core/editing/SpellChecker.h"
#include "core/editing/SplitElementCommand.h"
#include "core/editing/SplitTextNodeCommand.h"
#include "core/editing/SplitTextNodeContainingElementCommand.h"
#include "core/editing/TextIterator.h"
#include "core/editing/VisibleUnits.h"
#include "core/editing/WrapContentsInDummySpanCommand.h"
#include "core/editing/htmlediting.h"
#include "core/editing/markup.h"
#include "core/events/ScopedEventQueue.h"
#include "core/frame/LocalFrame.h"
#include "core/html/HTMLElement.h"
#include "core/rendering/InlineTextBox.h"
#include "core/rendering/RenderBlock.h"
#include "core/rendering/RenderText.h"

using namespace std;

namespace WebCore {

using namespace HTMLNames;

PassRefPtr<EditCommandComposition> EditCommandComposition::create(Document* document,
    const VisibleSelection& startingSelection, const VisibleSelection& endingSelection, EditAction editAction)
{
    return adoptRef(new EditCommandComposition(document, startingSelection, endingSelection, editAction));
}

EditCommandComposition::EditCommandComposition(Document* document, const VisibleSelection& startingSelection, const VisibleSelection& endingSelection, EditAction editAction)
    : m_document(document)
    , m_startingSelection(startingSelection)
    , m_endingSelection(endingSelection)
    , m_startingRootEditableElement(startingSelection.rootEditableElement())
    , m_endingRootEditableElement(endingSelection.rootEditableElement())
    , m_editAction(editAction)
{
}

bool EditCommandComposition::belongsTo(const LocalFrame& frame) const
{
    ASSERT(m_document);
    return m_document->frame() == &frame;
}

void EditCommandComposition::unapply()
{
    ASSERT(m_document);
    RefPtr<LocalFrame> frame = m_document->frame();
    ASSERT(frame);

    // Changes to the document may have been made since the last editing operation that require a layout, as in <rdar://problem/5658603>.
    // Low level operations, like RemoveNodeCommand, don't require a layout because the high level operations that use them perform one
    // if one is necessary (like for the creation of VisiblePositions).
    m_document->updateLayoutIgnorePendingStylesheets();

    {
        size_t size = m_commands.size();
        for (size_t i = size; i; --i)
            m_commands[i - 1]->doUnapply();
    }

    frame->editor().unappliedEditing(this);
}

void EditCommandComposition::reapply()
{
    ASSERT(m_document);
    RefPtr<LocalFrame> frame = m_document->frame();
    ASSERT(frame);

    // Changes to the document may have been made since the last editing operation that require a layout, as in <rdar://problem/5658603>.
    // Low level operations, like RemoveNodeCommand, don't require a layout because the high level operations that use them perform one
    // if one is necessary (like for the creation of VisiblePositions).
    m_document->updateLayoutIgnorePendingStylesheets();

    {
        size_t size = m_commands.size();
        for (size_t i = 0; i != size; ++i)
            m_commands[i]->doReapply();
    }

    frame->editor().reappliedEditing(this);
}

void EditCommandComposition::append(SimpleEditCommand* command)
{
    m_commands.append(command);
}

void EditCommandComposition::setStartingSelection(const VisibleSelection& selection)
{
    m_startingSelection = selection;
    m_startingRootEditableElement = selection.rootEditableElement();
}

void EditCommandComposition::setEndingSelection(const VisibleSelection& selection)
{
    m_endingSelection = selection;
    m_endingRootEditableElement = selection.rootEditableElement();
}

CompositeEditCommand::CompositeEditCommand(Document& document)
    : EditCommand(document)
{
}

CompositeEditCommand::~CompositeEditCommand()
{
    ASSERT(isTopLevelCommand() || !m_composition);
}

void CompositeEditCommand::apply()
{
    if (!endingSelection().isContentRichlyEditable()) {
        switch (editingAction()) {
        case EditActionTyping:
        case EditActionPaste:
        case EditActionDrag:
        case EditActionSetWritingDirection:
        case EditActionCut:
        case EditActionUnspecified:
            break;
        default:
            ASSERT_NOT_REACHED();
            return;
        }
    }
    ensureComposition();

    // Changes to the document may have been made since the last editing operation that require a layout, as in <rdar://problem/5658603>.
    // Low level operations, like RemoveNodeCommand, don't require a layout because the high level operations that use them perform one
    // if one is necessary (like for the creation of VisiblePositions).
    document().updateLayoutIgnorePendingStylesheets();

    LocalFrame* frame = document().frame();
    ASSERT(frame);
    {
        EventQueueScope eventQueueScope;
        doApply();
    }

    // Only need to call appliedEditing for top-level commands,
    // and TypingCommands do it on their own (see TypingCommand::typingAddedToOpenCommand).
    if (!isTypingCommand())
        frame->editor().appliedEditing(this);
    setShouldRetainAutocorrectionIndicator(false);
}

EditCommandComposition* CompositeEditCommand::ensureComposition()
{
    CompositeEditCommand* command = this;
    while (command && command->parent())
        command = command->parent();
    if (!command->m_composition)
        command->m_composition = EditCommandComposition::create(&document(), startingSelection(), endingSelection(), editingAction());
    return command->m_composition.get();
}

bool CompositeEditCommand::preservesTypingStyle() const
{
    return false;
}

bool CompositeEditCommand::isTypingCommand() const
{
    return false;
}

void CompositeEditCommand::setShouldRetainAutocorrectionIndicator(bool)
{
}

//
// sugary-sweet convenience functions to help create and apply edit commands in composite commands
//
void CompositeEditCommand::applyCommandToComposite(PassRefPtr<EditCommand> prpCommand)
{
    RefPtr<EditCommand> command = prpCommand;
    command->setParent(this);
    command->doApply();
    if (command->isSimpleEditCommand()) {
        command->setParent(0);
        ensureComposition()->append(toSimpleEditCommand(command.get()));
    }
    m_commands.append(command.release());
}

void CompositeEditCommand::applyCommandToComposite(PassRefPtr<CompositeEditCommand> command, const VisibleSelection& selection)
{
    command->setParent(this);
    if (selection != command->endingSelection()) {
        command->setStartingSelection(selection);
        command->setEndingSelection(selection);
    }
    command->doApply();
    m_commands.append(command);
}

void CompositeEditCommand::applyStyle(const EditingStyle* style, EditAction editingAction)
{
    applyCommandToComposite(ApplyStyleCommand::create(document(), style, editingAction));
}

void CompositeEditCommand::applyStyle(const EditingStyle* style, const Position& start, const Position& end, EditAction editingAction)
{
    applyCommandToComposite(ApplyStyleCommand::create(document(), style, start, end, editingAction));
}

void CompositeEditCommand::applyStyledElement(PassRefPtr<Element> element)
{
    applyCommandToComposite(ApplyStyleCommand::create(element, false));
}

void CompositeEditCommand::removeStyledElement(PassRefPtr<Element> element)
{
    applyCommandToComposite(ApplyStyleCommand::create(element, true));
}

void CompositeEditCommand::insertParagraphSeparator(bool useDefaultParagraphElement, bool pasteBlockqutoeIntoUnquotedArea)
{
    applyCommandToComposite(InsertParagraphSeparatorCommand::create(document(), useDefaultParagraphElement, pasteBlockqutoeIntoUnquotedArea));
}

bool CompositeEditCommand::isRemovableBlock(const Node* node)
{
    ASSERT(node);
    if (!isHTMLDivElement(*node))
        return false;

    Node* parentNode = node->parentNode();
    if (parentNode && parentNode->firstChild() != parentNode->lastChild())
        return false;

    if (!toElement(node)->hasAttributes())
        return true;

    return false;
}

void CompositeEditCommand::insertNodeBefore(PassRefPtr<Node> insertChild, PassRefPtr<Node> refChild, ShouldAssumeContentIsAlwaysEditable shouldAssumeContentIsAlwaysEditable)
{
    ASSERT(!isHTMLBodyElement(*refChild));
    applyCommandToComposite(InsertNodeBeforeCommand::create(insertChild, refChild, shouldAssumeContentIsAlwaysEditable));
}

void CompositeEditCommand::insertNodeAfter(PassRefPtr<Node> insertChild, PassRefPtr<Node> refChild)
{
    ASSERT(insertChild);
    ASSERT(refChild);
    ASSERT(!isHTMLBodyElement(*refChild));
    ContainerNode* parent = refChild->parentNode();
    ASSERT(parent);
    ASSERT(!parent->isShadowRoot());
    if (parent->lastChild() == refChild)
        appendNode(insertChild, parent);
    else {
        ASSERT(refChild->nextSibling());
        insertNodeBefore(insertChild, refChild->nextSibling());
    }
}

void CompositeEditCommand::insertNodeAt(PassRefPtr<Node> insertChild, const Position& editingPosition)
{
    ASSERT(isEditablePosition(editingPosition, ContentIsEditable, DoNotUpdateStyle));
    // For editing positions like [table, 0], insert before the table,
    // likewise for replaced elements, brs, etc.
    Position p = editingPosition.parentAnchoredEquivalent();
    Node* refChild = p.deprecatedNode();
    int offset = p.deprecatedEditingOffset();

    if (canHaveChildrenForEditing(refChild)) {
        Node* child = refChild->firstChild();
        for (int i = 0; child && i < offset; i++)
            child = child->nextSibling();
        if (child)
            insertNodeBefore(insertChild, child);
        else
            appendNode(insertChild, toContainerNode(refChild));
    } else if (caretMinOffset(refChild) >= offset)
        insertNodeBefore(insertChild, refChild);
    else if (refChild->isTextNode() && caretMaxOffset(refChild) > offset) {
        splitTextNode(toText(refChild), offset);

        // Mutation events (bug 22634) from the text node insertion may have removed the refChild
        if (!refChild->inDocument())
            return;
        insertNodeBefore(insertChild, refChild);
    } else
        insertNodeAfter(insertChild, refChild);
}

void CompositeEditCommand::appendNode(PassRefPtr<Node> node, PassRefPtr<ContainerNode> parent)
{
    ASSERT(canHaveChildrenForEditing(parent.get()));
    applyCommandToComposite(AppendNodeCommand::create(parent, node));
}

void CompositeEditCommand::removeChildrenInRange(PassRefPtr<Node> node, unsigned from, unsigned to)
{
    Vector<RefPtr<Node> > children;
    Node* child = node->traverseToChildAt(from);
    for (unsigned i = from; child && i < to; i++, child = child->nextSibling())
        children.append(child);

    size_t size = children.size();
    for (size_t i = 0; i < size; ++i)
        removeNode(children[i].release());
}

void CompositeEditCommand::removeNode(PassRefPtr<Node> node, ShouldAssumeContentIsAlwaysEditable shouldAssumeContentIsAlwaysEditable)
{
    if (!node || !node->nonShadowBoundaryParentNode())
        return;
    applyCommandToComposite(RemoveNodeCommand::create(node, shouldAssumeContentIsAlwaysEditable));
}

void CompositeEditCommand::removeNodePreservingChildren(PassRefPtr<Node> node, ShouldAssumeContentIsAlwaysEditable shouldAssumeContentIsAlwaysEditable)
{
    applyCommandToComposite(RemoveNodePreservingChildrenCommand::create(node, shouldAssumeContentIsAlwaysEditable));
}

void CompositeEditCommand::removeNodeAndPruneAncestors(PassRefPtr<Node> node, Node* excludeNode)
{
    ASSERT(node.get() != excludeNode);
    RefPtr<ContainerNode> parent = node->parentNode();
    removeNode(node);
    prune(parent.release(), excludeNode);
}

void CompositeEditCommand::moveRemainingSiblingsToNewParent(Node* node, Node* pastLastNodeToMove, PassRefPtr<Element> prpNewParent)
{
    NodeVector nodesToRemove;
    RefPtr<Element> newParent = prpNewParent;

    for (; node && node != pastLastNodeToMove; node = node->nextSibling())
        nodesToRemove.append(node);

    for (unsigned i = 0; i < nodesToRemove.size(); i++) {
        removeNode(nodesToRemove[i]);
        appendNode(nodesToRemove[i], newParent);
    }
}

void CompositeEditCommand::updatePositionForNodeRemovalPreservingChildren(Position& position, Node& node)
{
    int offset = (position.anchorType() == Position::PositionIsOffsetInAnchor) ? position.offsetInContainerNode() : 0;
    updatePositionForNodeRemoval(position, node);
    if (offset)
        position.moveToOffset(offset);
}

HTMLElement* CompositeEditCommand::replaceElementWithSpanPreservingChildrenAndAttributes(PassRefPtr<HTMLElement> node)
{
    // It would also be possible to implement all of ReplaceNodeWithSpanCommand
    // as a series of existing smaller edit commands.  Someone who wanted to
    // reduce the number of edit commands could do so here.
    RefPtr<ReplaceNodeWithSpanCommand> command = ReplaceNodeWithSpanCommand::create(node);
    applyCommandToComposite(command);
    // Returning a raw pointer here is OK because the command is retained by
    // applyCommandToComposite (thus retaining the span), and the span is also
    // in the DOM tree, and thus alive whie it has a parent.
    ASSERT(command->spanElement()->inDocument());
    return command->spanElement();
}

void CompositeEditCommand::prune(PassRefPtr<Node> node, Node* excludeNode)
{
    if (RefPtr<Node> highestNodeToRemove = highestNodeToRemoveInPruning(node.get(), excludeNode))
        removeNode(highestNodeToRemove.release());
}

void CompositeEditCommand::splitTextNode(PassRefPtr<Text> node, unsigned offset)
{
    applyCommandToComposite(SplitTextNodeCommand::create(node, offset));
}

void CompositeEditCommand::splitElement(PassRefPtr<Element> element, PassRefPtr<Node> atChild)
{
    applyCommandToComposite(SplitElementCommand::create(element, atChild));
}

void CompositeEditCommand::mergeIdenticalElements(PassRefPtr<Element> prpFirst, PassRefPtr<Element> prpSecond)
{
    RefPtr<Element> first = prpFirst;
    RefPtr<Element> second = prpSecond;
    ASSERT(!first->isDescendantOf(second.get()) && second != first);
    if (first->nextSibling() != second) {
        removeNode(second);
        insertNodeAfter(second, first);
    }
    applyCommandToComposite(MergeIdenticalElementsCommand::create(first, second));
}

void CompositeEditCommand::wrapContentsInDummySpan(PassRefPtr<Element> element)
{
    applyCommandToComposite(WrapContentsInDummySpanCommand::create(element));
}

void CompositeEditCommand::splitTextNodeContainingElement(PassRefPtr<Text> text, unsigned offset)
{
    applyCommandToComposite(SplitTextNodeContainingElementCommand::create(text, offset));
}

void CompositeEditCommand::insertTextIntoNode(PassRefPtr<Text> node, unsigned offset, const String& text)
{
    if (!text.isEmpty())
        applyCommandToComposite(InsertIntoTextNodeCommand::create(node, offset, text));
}

void CompositeEditCommand::deleteTextFromNode(PassRefPtr<Text> node, unsigned offset, unsigned count)
{
    applyCommandToComposite(DeleteFromTextNodeCommand::create(node, offset, count));
}

void CompositeEditCommand::replaceTextInNode(PassRefPtr<Text> prpNode, unsigned offset, unsigned count, const String& replacementText)
{
    RefPtr<Text> node(prpNode);
    applyCommandToComposite(DeleteFromTextNodeCommand::create(node, offset, count));
    if (!replacementText.isEmpty())
        applyCommandToComposite(InsertIntoTextNodeCommand::create(node, offset, replacementText));
}

Position CompositeEditCommand::replaceSelectedTextInNode(const String& text)
{
    Position start = endingSelection().start();
    Position end = endingSelection().end();
    if (start.containerNode() != end.containerNode() || !start.containerNode()->isTextNode() || isTabSpanTextNode(start.containerNode()))
        return Position();

    RefPtr<Text> textNode = start.containerText();
    replaceTextInNode(textNode, start.offsetInContainerNode(), end.offsetInContainerNode() - start.offsetInContainerNode(), text);

    return Position(textNode.release(), start.offsetInContainerNode() + text.length());
}

static void copyMarkers(const Vector<DocumentMarker*>& markerPointers, Vector<DocumentMarker>& markers)
{
    size_t arraySize = markerPointers.size();
    markers.reserveCapacity(arraySize);
    for (size_t i = 0; i < arraySize; ++i)
        markers.append(*markerPointers[i]);
}

void CompositeEditCommand::replaceTextInNodePreservingMarkers(PassRefPtr<Text> prpNode, unsigned offset, unsigned count, const String& replacementText)
{
    RefPtr<Text> node(prpNode);
    DocumentMarkerController& markerController = document().markers();
    Vector<DocumentMarker> markers;
    copyMarkers(markerController.markersInRange(Range::create(document(), node.get(), offset, node.get(), offset + count).get(), DocumentMarker::AllMarkers()), markers);
    replaceTextInNode(node, offset, count, replacementText);
    RefPtrWillBeRawPtr<Range> newRange = Range::create(document(), node.get(), offset, node.get(), offset + replacementText.length());
    for (size_t i = 0; i < markers.size(); ++i)
        markerController.addMarker(newRange.get(), markers[i].type(), markers[i].description());
}

Position CompositeEditCommand::positionOutsideTabSpan(const Position& pos)
{
    if (!isTabSpanTextNode(pos.anchorNode()))
        return pos;

    switch (pos.anchorType()) {
    case Position::PositionIsBeforeChildren:
    case Position::PositionIsAfterChildren:
        ASSERT_NOT_REACHED();
        return pos;
    case Position::PositionIsOffsetInAnchor:
        break;
    case Position::PositionIsBeforeAnchor:
        return positionInParentBeforeNode(*pos.anchorNode());
    case Position::PositionIsAfterAnchor:
        return positionInParentAfterNode(*pos.anchorNode());
    }

    Node* tabSpan = tabSpanNode(pos.containerNode());
    ASSERT(tabSpan);

    if (pos.offsetInContainerNode() <= caretMinOffset(pos.containerNode()))
        return positionInParentBeforeNode(*tabSpan);

    if (pos.offsetInContainerNode() >= caretMaxOffset(pos.containerNode()))
        return positionInParentAfterNode(*tabSpan);

    splitTextNodeContainingElement(toText(pos.containerNode()), pos.offsetInContainerNode());
    return positionInParentBeforeNode(*tabSpan);
}

void CompositeEditCommand::insertNodeAtTabSpanPosition(PassRefPtr<Node> node, const Position& pos)
{
    // insert node before, after, or at split of tab span
    insertNodeAt(node, positionOutsideTabSpan(pos));
}

void CompositeEditCommand::deleteSelection(bool smartDelete, bool mergeBlocksAfterDelete, bool expandForSpecialElements, bool sanitizeMarkup)
{
    if (endingSelection().isRange())
        applyCommandToComposite(DeleteSelectionCommand::create(document(), smartDelete, mergeBlocksAfterDelete, expandForSpecialElements, sanitizeMarkup));
}

void CompositeEditCommand::deleteSelection(const VisibleSelection &selection, bool smartDelete, bool mergeBlocksAfterDelete, bool expandForSpecialElements, bool sanitizeMarkup)
{
    if (selection.isRange())
        applyCommandToComposite(DeleteSelectionCommand::create(selection, smartDelete, mergeBlocksAfterDelete, expandForSpecialElements, sanitizeMarkup));
}

void CompositeEditCommand::removeCSSProperty(PassRefPtr<Element> element, CSSPropertyID property)
{
    applyCommandToComposite(RemoveCSSPropertyCommand::create(document(), element, property));
}

void CompositeEditCommand::removeNodeAttribute(PassRefPtr<Element> element, const QualifiedName& attribute)
{
    setNodeAttribute(element, attribute, AtomicString());
}

void CompositeEditCommand::setNodeAttribute(PassRefPtr<Element> element, const QualifiedName& attribute, const AtomicString& value)
{
    applyCommandToComposite(SetNodeAttributeCommand::create(element, attribute, value));
}

static inline bool containsOnlyWhitespace(const String& text)
{
    for (unsigned i = 0; i < text.length(); ++i) {
        if (!isWhitespace(text[i]))
            return false;
    }

    return true;
}

bool CompositeEditCommand::shouldRebalanceLeadingWhitespaceFor(const String& text) const
{
    return containsOnlyWhitespace(text);
}

bool CompositeEditCommand::canRebalance(const Position& position) const
{
    Node* node = position.containerNode();
    if (position.anchorType() != Position::PositionIsOffsetInAnchor || !node || !node->isTextNode())
        return false;

    Text* textNode = toText(node);
    if (textNode->length() == 0)
        return false;

    RenderObject* renderer = textNode->renderer();
    if (renderer && !renderer->style()->collapseWhiteSpace())
        return false;

    return true;
}

// FIXME: Doesn't go into text nodes that contribute adjacent text (siblings, cousins, etc).
void CompositeEditCommand::rebalanceWhitespaceAt(const Position& position)
{
    Node* node = position.containerNode();
    if (!canRebalance(position))
        return;

    // If the rebalance is for the single offset, and neither text[offset] nor text[offset - 1] are some form of whitespace, do nothing.
    int offset = position.deprecatedEditingOffset();
    String text = toText(node)->data();
    if (!isWhitespace(text[offset])) {
        offset--;
        if (offset < 0 || !isWhitespace(text[offset]))
            return;
    }

    rebalanceWhitespaceOnTextSubstring(toText(node), position.offsetInContainerNode(), position.offsetInContainerNode());
}

void CompositeEditCommand::rebalanceWhitespaceOnTextSubstring(PassRefPtr<Text> prpTextNode, int startOffset, int endOffset)
{
    RefPtr<Text> textNode = prpTextNode;

    String text = textNode->data();
    ASSERT(!text.isEmpty());

    // Set upstream and downstream to define the extent of the whitespace surrounding text[offset].
    int upstream = startOffset;
    while (upstream > 0 && isWhitespace(text[upstream - 1]))
        upstream--;

    int downstream = endOffset;
    while ((unsigned)downstream < text.length() && isWhitespace(text[downstream]))
        downstream++;

    int length = downstream - upstream;
    if (!length)
        return;

    VisiblePosition visibleUpstreamPos(Position(textNode, upstream));
    VisiblePosition visibleDownstreamPos(Position(textNode, downstream));

    String string = text.substring(upstream, length);
    String rebalancedString = stringWithRebalancedWhitespace(string,
    // FIXME: Because of the problem mentioned at the top of this function, we must also use nbsps at the start/end of the string because
    // this function doesn't get all surrounding whitespace, just the whitespace in the current text node.
                                                             isStartOfParagraph(visibleUpstreamPos) || upstream == 0,
                                                             isEndOfParagraph(visibleDownstreamPos) || (unsigned)downstream == text.length());

    if (string != rebalancedString)
        replaceTextInNodePreservingMarkers(textNode.release(), upstream, length, rebalancedString);
}

void CompositeEditCommand::prepareWhitespaceAtPositionForSplit(Position& position)
{
    Node* node = position.deprecatedNode();
    if (!node || !node->isTextNode())
        return;
    Text* textNode = toText(node);

    if (textNode->length() == 0)
        return;
    RenderObject* renderer = textNode->renderer();
    if (renderer && !renderer->style()->collapseWhiteSpace())
        return;

    // Delete collapsed whitespace so that inserting nbsps doesn't uncollapse it.
    Position upstreamPos = position.upstream();
    deleteInsignificantText(upstreamPos, position.downstream());
    position = upstreamPos.downstream();

    VisiblePosition visiblePos(position);
    VisiblePosition previousVisiblePos(visiblePos.previous());
    replaceCollapsibleWhitespaceWithNonBreakingSpaceIfNeeded(previousVisiblePos);
    replaceCollapsibleWhitespaceWithNonBreakingSpaceIfNeeded(visiblePos);
}

void CompositeEditCommand::replaceCollapsibleWhitespaceWithNonBreakingSpaceIfNeeded(const VisiblePosition& visiblePosition)
{
    if (!isCollapsibleWhitespace(visiblePosition.characterAfter()))
        return;
    Position pos = visiblePosition.deepEquivalent().downstream();
    if (!pos.containerNode() || !pos.containerNode()->isTextNode())
        return;
    replaceTextInNodePreservingMarkers(pos.containerText(), pos.offsetInContainerNode(), 1, nonBreakingSpaceString());
}

void CompositeEditCommand::rebalanceWhitespace()
{
    VisibleSelection selection = endingSelection();
    if (selection.isNone())
        return;

    rebalanceWhitespaceAt(selection.start());
    if (selection.isRange())
        rebalanceWhitespaceAt(selection.end());
}

void CompositeEditCommand::deleteInsignificantText(PassRefPtr<Text> textNode, unsigned start, unsigned end)
{
    if (!textNode || start >= end)
        return;

    document().updateLayout();

    RenderText* textRenderer = toRenderText(textNode->renderer());
    if (!textRenderer)
        return;

    Vector<InlineTextBox*> sortedTextBoxes;
    size_t sortedTextBoxesPosition = 0;

    for (InlineTextBox* textBox = textRenderer->firstTextBox(); textBox; textBox = textBox->nextTextBox())
        sortedTextBoxes.append(textBox);

    // If there is mixed directionality text, the boxes can be out of order,
    // (like Arabic with embedded LTR), so sort them first.
    if (textRenderer->containsReversedText())
        std::sort(sortedTextBoxes.begin(), sortedTextBoxes.end(), InlineTextBox::compareByStart);
    InlineTextBox* box = sortedTextBoxes.isEmpty() ? 0 : sortedTextBoxes[sortedTextBoxesPosition];

    if (!box) {
        // whole text node is empty
        removeNode(textNode);
        return;
    }

    unsigned length = textNode->length();
    if (start >= length || end > length)
        return;

    unsigned removed = 0;
    InlineTextBox* prevBox = 0;
    String str;

    // This loop structure works to process all gaps preceding a box,
    // and also will look at the gap after the last box.
    while (prevBox || box) {
        unsigned gapStart = prevBox ? prevBox->start() + prevBox->len() : 0;
        if (end < gapStart)
            // No more chance for any intersections
            break;

        unsigned gapEnd = box ? box->start() : length;
        bool indicesIntersect = start <= gapEnd && end >= gapStart;
        int gapLen = gapEnd - gapStart;
        if (indicesIntersect && gapLen > 0) {
            gapStart = max(gapStart, start);
            if (str.isNull())
                str = textNode->data().substring(start, end - start);
            // remove text in the gap
            str.remove(gapStart - start - removed, gapLen);
            removed += gapLen;
        }

        prevBox = box;
        if (box) {
            if (++sortedTextBoxesPosition < sortedTextBoxes.size())
                box = sortedTextBoxes[sortedTextBoxesPosition];
            else
                box = 0;
        }
    }

    if (!str.isNull()) {
        // Replace the text between start and end with our pruned version.
        if (!str.isEmpty())
            replaceTextInNode(textNode, start, end - start, str);
        else {
            // Assert that we are not going to delete all of the text in the node.
            // If we were, that should have been done above with the call to
            // removeNode and return.
            ASSERT(start > 0 || end - start < textNode->length());
            deleteTextFromNode(textNode, start, end - start);
        }
    }
}

void CompositeEditCommand::deleteInsignificantText(const Position& start, const Position& end)
{
    if (start.isNull() || end.isNull())
        return;

    if (comparePositions(start, end) >= 0)
        return;

    Vector<RefPtr<Text> > nodes;
    for (Node* node = start.deprecatedNode(); node; node = NodeTraversal::next(*node)) {
        if (node->isTextNode())
            nodes.append(toText(node));
        if (node == end.deprecatedNode())
            break;
    }

    for (size_t i = 0; i < nodes.size(); ++i) {
        Text* textNode = nodes[i].get();
        int startOffset = textNode == start.deprecatedNode() ? start.deprecatedEditingOffset() : 0;
        int endOffset = textNode == end.deprecatedNode() ? end.deprecatedEditingOffset() : static_cast<int>(textNode->length());
        deleteInsignificantText(textNode, startOffset, endOffset);
    }
}

void CompositeEditCommand::deleteInsignificantTextDownstream(const Position& pos)
{
    Position end = VisiblePosition(pos, VP_DEFAULT_AFFINITY).next().deepEquivalent().downstream();
    deleteInsignificantText(pos, end);
}

PassRefPtr<Node> CompositeEditCommand::appendBlockPlaceholder(PassRefPtr<Element> container)
{
    if (!container)
        return nullptr;

    document().updateLayoutIgnorePendingStylesheets();

    // Should assert isRenderBlockFlow || isInlineFlow when deletion improves. See 4244964.
    ASSERT(container->renderer());

    RefPtr<Node> placeholder = createBlockPlaceholderElement(document());
    appendNode(placeholder, container);
    return placeholder.release();
}

PassRefPtr<Node> CompositeEditCommand::insertBlockPlaceholder(const Position& pos)
{
    if (pos.isNull())
        return nullptr;

    // Should assert isRenderBlockFlow || isInlineFlow when deletion improves. See 4244964.
    ASSERT(pos.deprecatedNode()->renderer());

    RefPtr<Node> placeholder = createBlockPlaceholderElement(document());
    insertNodeAt(placeholder, pos);
    return placeholder.release();
}

PassRefPtr<Node> CompositeEditCommand::addBlockPlaceholderIfNeeded(Element* container)
{
    if (!container)
        return nullptr;

    document().updateLayoutIgnorePendingStylesheets();

    RenderObject* renderer = container->renderer();
    if (!renderer || !renderer->isRenderBlockFlow())
        return nullptr;

    // append the placeholder to make sure it follows
    // any unrendered blocks
    RenderBlock* block = toRenderBlock(renderer);
    if (block->height() == 0 || (block->isListItem() && block->isEmpty()))
        return appendBlockPlaceholder(container);

    return nullptr;
}

// Assumes that the position is at a placeholder and does the removal without much checking.
void CompositeEditCommand::removePlaceholderAt(const Position& p)
{
    ASSERT(lineBreakExistsAtPosition(p));

    // We are certain that the position is at a line break, but it may be a br or a preserved newline.
    if (isHTMLBRElement(*p.anchorNode())) {
        removeNode(p.anchorNode());
        return;
    }

    deleteTextFromNode(toText(p.anchorNode()), p.offsetInContainerNode(), 1);
}

PassRefPtr<Node> CompositeEditCommand::insertNewDefaultParagraphElementAt(const Position& position)
{
    RefPtr<Element> paragraphElement = createDefaultParagraphElement(document());
    paragraphElement->appendChild(createBreakElement(document()));
    insertNodeAt(paragraphElement, position);
    return paragraphElement.release();
}

// If the paragraph is not entirely within it's own block, create one and move the paragraph into
// it, and return that block.  Otherwise return 0.
PassRefPtr<Node> CompositeEditCommand::moveParagraphContentsToNewBlockIfNecessary(const Position& pos)
{
    if (pos.isNull())
        return nullptr;

    document().updateLayoutIgnorePendingStylesheets();

    // It's strange that this function is responsible for verifying that pos has not been invalidated
    // by an earlier call to this function.  The caller, applyBlockStyle, should do this.
    VisiblePosition visiblePos(pos, VP_DEFAULT_AFFINITY);
    VisiblePosition visibleParagraphStart(startOfParagraph(visiblePos));
    VisiblePosition visibleParagraphEnd = endOfParagraph(visiblePos);
    VisiblePosition next = visibleParagraphEnd.next();
    VisiblePosition visibleEnd = next.isNotNull() ? next : visibleParagraphEnd;

    Position upstreamStart = visibleParagraphStart.deepEquivalent().upstream();
    Position upstreamEnd = visibleEnd.deepEquivalent().upstream();

    // If there are no VisiblePositions in the same block as pos then
    // upstreamStart will be outside the paragraph
    if (comparePositions(pos, upstreamStart) < 0)
        return nullptr;

    // Perform some checks to see if we need to perform work in this function.
    if (isBlock(upstreamStart.deprecatedNode())) {
        // If the block is the root editable element, always move content to a new block,
        // since it is illegal to modify attributes on the root editable element for editing.
        if (upstreamStart.deprecatedNode() == editableRootForPosition(upstreamStart)) {
            // If the block is the root editable element and it contains no visible content, create a new
            // block but don't try and move content into it, since there's nothing for moveParagraphs to move.
            if (!Position::hasRenderedNonAnonymousDescendantsWithHeight(upstreamStart.deprecatedNode()->renderer()))
                return insertNewDefaultParagraphElementAt(upstreamStart);
        } else if (isBlock(upstreamEnd.deprecatedNode())) {
            if (!upstreamEnd.deprecatedNode()->isDescendantOf(upstreamStart.deprecatedNode())) {
                // If the paragraph end is a descendant of paragraph start, then we need to run
                // the rest of this function. If not, we can bail here.
                return nullptr;
            }
        } else if (enclosingBlock(upstreamEnd.deprecatedNode()) != upstreamStart.deprecatedNode()) {
            // The visibleEnd.  It must be an ancestor of the paragraph start.
            // We can bail as we have a full block to work with.
            ASSERT(upstreamStart.deprecatedNode()->isDescendantOf(enclosingBlock(upstreamEnd.deprecatedNode())));
            return nullptr;
        } else if (isEndOfEditableOrNonEditableContent(visibleEnd)) {
            // At the end of the editable region. We can bail here as well.
            return nullptr;
        }
    }

    RefPtr<Node> newBlock = insertNewDefaultParagraphElementAt(upstreamStart);

    bool endWasBr = isHTMLBRElement(*visibleParagraphEnd.deepEquivalent().deprecatedNode());

    moveParagraphs(visibleParagraphStart, visibleParagraphEnd, VisiblePosition(firstPositionInNode(newBlock.get())));

    if (newBlock->lastChild() && isHTMLBRElement(*newBlock->lastChild()) && !endWasBr)
        removeNode(newBlock->lastChild());

    return newBlock.release();
}

void CompositeEditCommand::pushAnchorElementDown(Node* anchorNode)
{
    if (!anchorNode)
        return;

    ASSERT(anchorNode->isLink());

    setEndingSelection(VisibleSelection::selectionFromContentsOfNode(anchorNode));
    applyStyledElement(toElement(anchorNode));
    // Clones of anchorNode have been pushed down, now remove it.
    if (anchorNode->inDocument())
        removeNodePreservingChildren(anchorNode);
}

// Clone the paragraph between start and end under blockElement,
// preserving the hierarchy up to outerNode.

void CompositeEditCommand::cloneParagraphUnderNewElement(const Position& start, const Position& end, Node* passedOuterNode, Element* blockElement)
{
    ASSERT(comparePositions(start, end) <= 0);

    // First we clone the outerNode
    RefPtr<Node> lastNode;
    RefPtr<Node> outerNode = passedOuterNode;

    if (outerNode->isRootEditableElement()) {
        lastNode = blockElement;
    } else {
        lastNode = outerNode->cloneNode(isRenderedTableElement(outerNode.get()));
        appendNode(lastNode, blockElement);
    }

    if (start.anchorNode() != outerNode && lastNode->isElementNode() && start.anchorNode()->isDescendantOf(outerNode.get())) {
        Vector<RefPtr<Node> > ancestors;

        // Insert each node from innerNode to outerNode (excluded) in a list.
        for (Node* n = start.deprecatedNode(); n && n != outerNode; n = n->parentNode())
            ancestors.append(n);

        // Clone every node between start.deprecatedNode() and outerBlock.

        for (size_t i = ancestors.size(); i != 0; --i) {
            Node* item = ancestors[i - 1].get();
            RefPtr<Node> child = item->cloneNode(isRenderedTableElement(item));
            appendNode(child, toElement(lastNode));
            lastNode = child.release();
        }
    }

    // Scripts specified in javascript protocol may remove |outerNode|
    // during insertion, e.g. <iframe src="javascript:...">
    if (!outerNode->inDocument())
        return;

    // Handle the case of paragraphs with more than one node,
    // cloning all the siblings until end.deprecatedNode() is reached.

    if (start.deprecatedNode() != end.deprecatedNode() && !start.deprecatedNode()->isDescendantOf(end.deprecatedNode())) {
        // If end is not a descendant of outerNode we need to
        // find the first common ancestor to increase the scope
        // of our nextSibling traversal.
        while (!end.deprecatedNode()->isDescendantOf(outerNode.get())) {
            outerNode = outerNode->parentNode();
        }

        RefPtr<Node> startNode = start.deprecatedNode();
        for (RefPtr<Node> node = NodeTraversal::nextSkippingChildren(*startNode, outerNode.get()); node; node = NodeTraversal::nextSkippingChildren(*node, outerNode.get())) {
            // Move lastNode up in the tree as much as node was moved up in the
            // tree by NodeTraversal::nextSkippingChildren, so that the relative depth between
            // node and the original start node is maintained in the clone.
            while (startNode->parentNode() != node->parentNode()) {
                startNode = startNode->parentNode();
                lastNode = lastNode->parentNode();
            }

            RefPtr<Node> clonedNode = node->cloneNode(true);
            insertNodeAfter(clonedNode, lastNode);
            lastNode = clonedNode.release();
            if (node == end.deprecatedNode() || end.deprecatedNode()->isDescendantOf(node.get()))
                break;
        }
    }
}


// There are bugs in deletion when it removes a fully selected table/list.
// It expands and removes the entire table/list, but will let content
// before and after the table/list collapse onto one line.
// Deleting a paragraph will leave a placeholder. Remove it (and prune
// empty or unrendered parents).

void CompositeEditCommand::cleanupAfterDeletion(VisiblePosition destination)
{
    VisiblePosition caretAfterDelete = endingSelection().visibleStart();
    Node* destinationNode = destination.deepEquivalent().anchorNode();
    if (caretAfterDelete != destination && isStartOfParagraph(caretAfterDelete) && isEndOfParagraph(caretAfterDelete)) {
        // Note: We want the rightmost candidate.
        Position position = caretAfterDelete.deepEquivalent().downstream();
        Node* node = position.deprecatedNode();

        // Bail if we'd remove an ancestor of our destination.
        if (destinationNode && destinationNode->isDescendantOf(node))
            return;

        // Normally deletion will leave a br as a placeholder.
        if (isHTMLBRElement(*node)) {
            removeNodeAndPruneAncestors(node, destinationNode);

            // If the selection to move was empty and in an empty block that
            // doesn't require a placeholder to prop itself open (like a bordered
            // div or an li), remove it during the move (the list removal code
            // expects this behavior).
        } else if (isBlock(node)) {
            // If caret position after deletion and destination position coincides,
            // node should not be removed.
            if (!position.rendersInDifferentPosition(destination.deepEquivalent())) {
                prune(node, destinationNode);
                return;
            }
            removeNodeAndPruneAncestors(node, destinationNode);
        }
        else if (lineBreakExistsAtPosition(position)) {
            // There is a preserved '\n' at caretAfterDelete.
            // We can safely assume this is a text node.
            Text* textNode = toText(node);
            if (textNode->length() == 1)
                removeNodeAndPruneAncestors(node, destinationNode);
            else
                deleteTextFromNode(textNode, position.deprecatedEditingOffset(), 1);
        }
    }
}

// This is a version of moveParagraph that preserves style by keeping the original markup
// It is currently used only by IndentOutdentCommand but it is meant to be used in the
// future by several other commands such as InsertList and the align commands.
// The blockElement parameter is the element to move the paragraph to,
// outerNode is the top element of the paragraph hierarchy.

void CompositeEditCommand::moveParagraphWithClones(const VisiblePosition& startOfParagraphToMove, const VisiblePosition& endOfParagraphToMove, Element* blockElement, Node* outerNode)
{
    ASSERT(outerNode);
    ASSERT(blockElement);

    VisiblePosition beforeParagraph = startOfParagraphToMove.previous();
    VisiblePosition afterParagraph(endOfParagraphToMove.next());

    // We upstream() the end and downstream() the start so that we don't include collapsed whitespace in the move.
    // When we paste a fragment, spaces after the end and before the start are treated as though they were rendered.
    Position start = startOfParagraphToMove.deepEquivalent().downstream();
    Position end = startOfParagraphToMove == endOfParagraphToMove ? start : endOfParagraphToMove.deepEquivalent().upstream();

    cloneParagraphUnderNewElement(start, end, outerNode, blockElement);

    setEndingSelection(VisibleSelection(start, end, DOWNSTREAM));
    deleteSelection(false, false, false, false);

    // There are bugs in deletion when it removes a fully selected table/list.
    // It expands and removes the entire table/list, but will let content
    // before and after the table/list collapse onto one line.

    cleanupAfterDeletion();

    // Add a br if pruning an empty block level element caused a collapse.  For example:
    // foo^
    // <div>bar</div>
    // baz
    // Imagine moving 'bar' to ^.  'bar' will be deleted and its div pruned.  That would
    // cause 'baz' to collapse onto the line with 'foobar' unless we insert a br.
    // Must recononicalize these two VisiblePositions after the pruning above.
    beforeParagraph = VisiblePosition(beforeParagraph.deepEquivalent());
    afterParagraph = VisiblePosition(afterParagraph.deepEquivalent());

    if (beforeParagraph.isNotNull() && !isRenderedTable(beforeParagraph.deepEquivalent().deprecatedNode())
        && ((!isEndOfParagraph(beforeParagraph) && !isStartOfParagraph(beforeParagraph)) || beforeParagraph == afterParagraph)) {
        // FIXME: Trim text between beforeParagraph and afterParagraph if they aren't equal.
        insertNodeAt(createBreakElement(document()), beforeParagraph.deepEquivalent());
    }
}

void CompositeEditCommand::moveParagraph(const VisiblePosition& startOfParagraphToMove, const VisiblePosition& endOfParagraphToMove, const VisiblePosition& destination, bool preserveSelection, bool preserveStyle, Node* constrainingAncestor)
{
    ASSERT(isStartOfParagraph(startOfParagraphToMove));
    ASSERT(isEndOfParagraph(endOfParagraphToMove));
    moveParagraphs(startOfParagraphToMove, endOfParagraphToMove, destination, preserveSelection, preserveStyle, constrainingAncestor);
}

void CompositeEditCommand::moveParagraphs(const VisiblePosition& startOfParagraphToMove, const VisiblePosition& endOfParagraphToMove, const VisiblePosition& destination, bool preserveSelection, bool preserveStyle, Node* constrainingAncestor)
{
    if (startOfParagraphToMove == destination)
        return;

    int startIndex = -1;
    int endIndex = -1;
    int destinationIndex = -1;
    bool originalIsDirectional = endingSelection().isDirectional();
    if (preserveSelection && !endingSelection().isNone()) {
        VisiblePosition visibleStart = endingSelection().visibleStart();
        VisiblePosition visibleEnd = endingSelection().visibleEnd();

        bool startAfterParagraph = comparePositions(visibleStart, endOfParagraphToMove) > 0;
        bool endBeforeParagraph = comparePositions(visibleEnd, startOfParagraphToMove) < 0;

        if (!startAfterParagraph && !endBeforeParagraph) {
            bool startInParagraph = comparePositions(visibleStart, startOfParagraphToMove) >= 0;
            bool endInParagraph = comparePositions(visibleEnd, endOfParagraphToMove) <= 0;

            startIndex = 0;
            if (startInParagraph) {
                RefPtrWillBeRawPtr<Range> startRange = Range::create(document(), startOfParagraphToMove.deepEquivalent().parentAnchoredEquivalent(), visibleStart.deepEquivalent().parentAnchoredEquivalent());
                startIndex = TextIterator::rangeLength(startRange.get(), true);
            }

            endIndex = 0;
            if (endInParagraph) {
                RefPtrWillBeRawPtr<Range> endRange = Range::create(document(), startOfParagraphToMove.deepEquivalent().parentAnchoredEquivalent(), visibleEnd.deepEquivalent().parentAnchoredEquivalent());
                endIndex = TextIterator::rangeLength(endRange.get(), true);
            }
        }
    }

    VisiblePosition beforeParagraph = startOfParagraphToMove.previous(CannotCrossEditingBoundary);
    VisiblePosition afterParagraph(endOfParagraphToMove.next(CannotCrossEditingBoundary));

    // We upstream() the end and downstream() the start so that we don't include collapsed whitespace in the move.
    // When we paste a fragment, spaces after the end and before the start are treated as though they were rendered.
    Position start = startOfParagraphToMove.deepEquivalent().downstream();
    Position end = endOfParagraphToMove.deepEquivalent().upstream();

    // start and end can't be used directly to create a Range; they are "editing positions"
    Position startRangeCompliant = start.parentAnchoredEquivalent();
    Position endRangeCompliant = end.parentAnchoredEquivalent();
    RefPtrWillBeRawPtr<Range> range = Range::create(document(), startRangeCompliant.deprecatedNode(), startRangeCompliant.deprecatedEditingOffset(), endRangeCompliant.deprecatedNode(), endRangeCompliant.deprecatedEditingOffset());

    // FIXME: This is an inefficient way to preserve style on nodes in the paragraph to move. It
    // shouldn't matter though, since moved paragraphs will usually be quite small.
    RefPtr<DocumentFragment> fragment = startOfParagraphToMove != endOfParagraphToMove ?
        createFragmentFromMarkup(document(), createMarkup(range.get(), 0, DoNotAnnotateForInterchange, true, DoNotResolveURLs, constrainingAncestor), "") : nullptr;

    // A non-empty paragraph's style is moved when we copy and move it.  We don't move
    // anything if we're given an empty paragraph, but an empty paragraph can have style
    // too, <div><b><br></b></div> for example.  Save it so that we can preserve it later.
    RefPtr<EditingStyle> styleInEmptyParagraph;
    if (startOfParagraphToMove == endOfParagraphToMove && preserveStyle) {
        styleInEmptyParagraph = EditingStyle::create(startOfParagraphToMove.deepEquivalent());
        styleInEmptyParagraph->mergeTypingStyle(&document());
        // The moved paragraph should assume the block style of the destination.
        styleInEmptyParagraph->removeBlockProperties();
    }

    // FIXME (5098931): We should add a new insert action "WebViewInsertActionMoved" and call shouldInsertFragment here.

    setEndingSelection(VisibleSelection(start, end, DOWNSTREAM));
    document().frame()->spellChecker().clearMisspellingsAndBadGrammar(endingSelection());
    deleteSelection(false, false, false, false);

    ASSERT(destination.deepEquivalent().inDocument());
    cleanupAfterDeletion(destination);
    ASSERT(destination.deepEquivalent().inDocument());

    // Add a br if pruning an empty block level element caused a collapse. For example:
    // foo^
    // <div>bar</div>
    // baz
    // Imagine moving 'bar' to ^. 'bar' will be deleted and its div pruned. That would
    // cause 'baz' to collapse onto the line with 'foobar' unless we insert a br.
    // Must recononicalize these two VisiblePositions after the pruning above.
    beforeParagraph = VisiblePosition(beforeParagraph.deepEquivalent());
    afterParagraph = VisiblePosition(afterParagraph.deepEquivalent());
    if (beforeParagraph.isNotNull() && (!isEndOfParagraph(beforeParagraph) || beforeParagraph == afterParagraph)) {
        // FIXME: Trim text between beforeParagraph and afterParagraph if they aren't equal.
        insertNodeAt(createBreakElement(document()), beforeParagraph.deepEquivalent());
        // Need an updateLayout here in case inserting the br has split a text node.
        document().updateLayoutIgnorePendingStylesheets();
    }

    RefPtrWillBeRawPtr<Range> startToDestinationRange(Range::create(document(), firstPositionInNode(document().documentElement()), destination.deepEquivalent().parentAnchoredEquivalent()));
    destinationIndex = TextIterator::rangeLength(startToDestinationRange.get(), true);

    setEndingSelection(VisibleSelection(destination, originalIsDirectional));
    ASSERT(endingSelection().isCaretOrRange());
    ReplaceSelectionCommand::CommandOptions options = ReplaceSelectionCommand::SelectReplacement | ReplaceSelectionCommand::MovingParagraph;
    if (!preserveStyle)
        options |= ReplaceSelectionCommand::MatchStyle;
    applyCommandToComposite(ReplaceSelectionCommand::create(document(), fragment, options));

    document().frame()->spellChecker().markMisspellingsAndBadGrammar(endingSelection());

    // If the selection is in an empty paragraph, restore styles from the old empty paragraph to the new empty paragraph.
    bool selectionIsEmptyParagraph = endingSelection().isCaret() && isStartOfParagraph(endingSelection().visibleStart()) && isEndOfParagraph(endingSelection().visibleStart());
    if (styleInEmptyParagraph && selectionIsEmptyParagraph)
        applyStyle(styleInEmptyParagraph.get());

    if (preserveSelection && startIndex != -1) {
        if (Element* documentElement = document().documentElement()) {
            // Fragment creation (using createMarkup) incorrectly uses regular
            // spaces instead of nbsps for some spaces that were rendered (11475), which
            // causes spaces to be collapsed during the move operation. This results
            // in a call to rangeFromLocationAndLength with a location past the end
            // of the document (which will return null).
            RefPtrWillBeRawPtr<Range> start = PlainTextRange(destinationIndex + startIndex).createRangeForSelection(*documentElement);
            RefPtrWillBeRawPtr<Range> end = PlainTextRange(destinationIndex + endIndex).createRangeForSelection(*documentElement);
            if (start && end)
                setEndingSelection(VisibleSelection(start->startPosition(), end->startPosition(), DOWNSTREAM, originalIsDirectional));
        }
    }
}

// FIXME: Send an appropriate shouldDeleteRange call.
bool CompositeEditCommand::breakOutOfEmptyListItem()
{
    RefPtr<Node> emptyListItem = enclosingEmptyListItem(endingSelection().visibleStart());
    if (!emptyListItem)
        return false;

    RefPtr<EditingStyle> style = EditingStyle::create(endingSelection().start());
    style->mergeTypingStyle(&document());

    RefPtr<ContainerNode> listNode = emptyListItem->parentNode();
    // FIXME: Can't we do something better when the immediate parent wasn't a list node?
    if (!listNode
        || (!isHTMLUListElement(*listNode) && !isHTMLOListElement(*listNode))
        || !listNode->rendererIsEditable()
        || listNode == emptyListItem->rootEditableElement())
        return false;

    RefPtr<Element> newBlock = nullptr;
    if (ContainerNode* blockEnclosingList = listNode->parentNode()) {
        if (isHTMLLIElement(*blockEnclosingList)) { // listNode is inside another list item
            if (visiblePositionAfterNode(*blockEnclosingList) == visiblePositionAfterNode(*listNode)) {
                // If listNode appears at the end of the outer list item, then move listNode outside of this list item
                // e.g. <ul><li>hello <ul><li><br></li></ul> </li></ul> should become <ul><li>hello</li> <ul><li><br></li></ul> </ul> after this section
                // If listNode does NOT appear at the end, then we should consider it as a regular paragraph.
                // e.g. <ul><li> <ul><li><br></li></ul> hello</li></ul> should become <ul><li> <div><br></div> hello</li></ul> at the end
                splitElement(toElement(blockEnclosingList), listNode);
                removeNodePreservingChildren(listNode->parentNode());
                newBlock = createListItemElement(document());
            }
            // If listNode does NOT appear at the end of the outer list item, then behave as if in a regular paragraph.
        } else if (isHTMLOListElement(*blockEnclosingList) || isHTMLUListElement(*blockEnclosingList)) {
            newBlock = createListItemElement(document());
        }
    }
    if (!newBlock)
        newBlock = createDefaultParagraphElement(document());

    RefPtr<Node> previousListNode = emptyListItem->isElementNode() ? ElementTraversal::previousSibling(*emptyListItem): emptyListItem->previousSibling();
    RefPtr<Node> nextListNode = emptyListItem->isElementNode() ? ElementTraversal::nextSibling(*emptyListItem): emptyListItem->nextSibling();
    if (isListItem(nextListNode.get()) || isListElement(nextListNode.get())) {
        // If emptyListItem follows another list item or nested list, split the list node.
        if (isListItem(previousListNode.get()) || isListElement(previousListNode.get()))
            splitElement(toElement(listNode), emptyListItem);

        // If emptyListItem is followed by other list item or nested list, then insert newBlock before the list node.
        // Because we have splitted the element, emptyListItem is the first element in the list node.
        // i.e. insert newBlock before ul or ol whose first element is emptyListItem
        insertNodeBefore(newBlock, listNode);
        removeNode(emptyListItem);
    } else {
        // When emptyListItem does not follow any list item or nested list, insert newBlock after the enclosing list node.
        // Remove the enclosing node if emptyListItem is the only child; otherwise just remove emptyListItem.
        insertNodeAfter(newBlock, listNode);
        removeNode(isListItem(previousListNode.get()) || isListElement(previousListNode.get()) ? emptyListItem.get() : listNode.get());
    }

    appendBlockPlaceholder(newBlock);
    setEndingSelection(VisibleSelection(firstPositionInNode(newBlock.get()), DOWNSTREAM, endingSelection().isDirectional()));

    style->prepareToApplyAt(endingSelection().start());
    if (!style->isEmpty())
        applyStyle(style.get());

    return true;
}

// If the caret is in an empty quoted paragraph, and either there is nothing before that
// paragraph, or what is before is unquoted, and the user presses delete, unquote that paragraph.
bool CompositeEditCommand::breakOutOfEmptyMailBlockquotedParagraph()
{
    if (!endingSelection().isCaret())
        return false;

    VisiblePosition caret(endingSelection().visibleStart());
    Node* highestBlockquote = highestEnclosingNodeOfType(caret.deepEquivalent(), &isMailBlockquote);
    if (!highestBlockquote)
        return false;

    if (!isStartOfParagraph(caret) || !isEndOfParagraph(caret))
        return false;

    VisiblePosition previous(caret.previous(CannotCrossEditingBoundary));
    // Only move forward if there's nothing before the caret, or if there's unquoted content before it.
    if (enclosingNodeOfType(previous.deepEquivalent(), &isMailBlockquote))
        return false;

    RefPtr<Node> br = createBreakElement(document());
    // We want to replace this quoted paragraph with an unquoted one, so insert a br
    // to hold the caret before the highest blockquote.
    insertNodeBefore(br, highestBlockquote);
    VisiblePosition atBR(positionBeforeNode(br.get()));
    // If the br we inserted collapsed, for example foo<br><blockquote>...</blockquote>, insert
    // a second one.
    if (!isStartOfParagraph(atBR))
        insertNodeBefore(createBreakElement(document()), br);
    setEndingSelection(VisibleSelection(atBR, endingSelection().isDirectional()));

    // If this is an empty paragraph there must be a line break here.
    if (!lineBreakExistsAtVisiblePosition(caret))
        return false;

    Position caretPos(caret.deepEquivalent().downstream());
    // A line break is either a br or a preserved newline.
    ASSERT(isHTMLBRElement(caretPos.deprecatedNode()) || (caretPos.deprecatedNode()->isTextNode() && caretPos.deprecatedNode()->renderer()->style()->preserveNewline()));

    if (isHTMLBRElement(*caretPos.deprecatedNode()))
        removeNodeAndPruneAncestors(caretPos.deprecatedNode());
    else if (caretPos.deprecatedNode()->isTextNode()) {
        ASSERT(caretPos.deprecatedEditingOffset() == 0);
        Text* textNode = toText(caretPos.deprecatedNode());
        ContainerNode* parentNode = textNode->parentNode();
        // The preserved newline must be the first thing in the node, since otherwise the previous
        // paragraph would be quoted, and we verified that it wasn't above.
        deleteTextFromNode(textNode, 0, 1);
        prune(parentNode);
    }

    return true;
}

// Operations use this function to avoid inserting content into an anchor when at the start or the end of
// that anchor, as in NSTextView.
// FIXME: This is only an approximation of NSTextViews insertion behavior, which varies depending on how
// the caret was made.
Position CompositeEditCommand::positionAvoidingSpecialElementBoundary(const Position& original)
{
    if (original.isNull())
        return original;

    VisiblePosition visiblePos(original);
    Node* enclosingAnchor = enclosingAnchorElement(original);
    Position result = original;

    if (!enclosingAnchor)
        return result;

    // Don't avoid block level anchors, because that would insert content into the wrong paragraph.
    if (enclosingAnchor && !isBlock(enclosingAnchor)) {
        VisiblePosition firstInAnchor(firstPositionInNode(enclosingAnchor));
        VisiblePosition lastInAnchor(lastPositionInNode(enclosingAnchor));
        // If visually just after the anchor, insert *inside* the anchor unless it's the last
        // VisiblePosition in the document, to match NSTextView.
        if (visiblePos == lastInAnchor) {
            // Make sure anchors are pushed down before avoiding them so that we don't
            // also avoid structural elements like lists and blocks (5142012).
            if (original.deprecatedNode() != enclosingAnchor && original.deprecatedNode()->parentNode() != enclosingAnchor) {
                pushAnchorElementDown(enclosingAnchor);
                enclosingAnchor = enclosingAnchorElement(original);
                if (!enclosingAnchor)
                    return original;
            }
            // Don't insert outside an anchor if doing so would skip over a line break.  It would
            // probably be safe to move the line break so that we could still avoid the anchor here.
            Position downstream(visiblePos.deepEquivalent().downstream());
            if (lineBreakExistsAtVisiblePosition(visiblePos) && downstream.deprecatedNode()->isDescendantOf(enclosingAnchor))
                return original;

            result = positionInParentAfterNode(*enclosingAnchor);
        }
        // If visually just before an anchor, insert *outside* the anchor unless it's the first
        // VisiblePosition in a paragraph, to match NSTextView.
        if (visiblePos == firstInAnchor) {
            // Make sure anchors are pushed down before avoiding them so that we don't
            // also avoid structural elements like lists and blocks (5142012).
            if (original.deprecatedNode() != enclosingAnchor && original.deprecatedNode()->parentNode() != enclosingAnchor) {
                pushAnchorElementDown(enclosingAnchor);
                enclosingAnchor = enclosingAnchorElement(original);
            }
            if (!enclosingAnchor)
                return original;

            result = positionInParentBeforeNode(*enclosingAnchor);
        }
    }

    if (result.isNull() || !editableRootForPosition(result))
        result = original;

    return result;
}

// Splits the tree parent by parent until we reach the specified ancestor. We use VisiblePositions
// to determine if the split is necessary. Returns the last split node.
PassRefPtr<Node> CompositeEditCommand::splitTreeToNode(Node* start, Node* end, bool shouldSplitAncestor)
{
    ASSERT(start);
    ASSERT(end);
    ASSERT(start != end);

    RefPtr<Node> node;
    if (shouldSplitAncestor && end->parentNode())
        end = end->parentNode();

    RefPtr<Node> endNode = end;
    for (node = start; node && node->parentNode() != endNode; node = node->parentNode()) {
        if (!node->parentNode()->isElementNode())
            break;
        // Do not split a node when doing so introduces an empty node.
        VisiblePosition positionInParent(firstPositionInNode(node->parentNode()));
        VisiblePosition positionInNode(firstPositionInOrBeforeNode(node.get()));
        if (positionInParent != positionInNode)
            splitElement(toElement(node->parentNode()), node);
    }

    return node.release();
}

PassRefPtr<Element> createBlockPlaceholderElement(Document& document)
{
    RefPtr<Element> breakNode = document.createElement(brTag, false);
    return breakNode.release();
}

} // namespace WebCore
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root/Source/core/editing/CompositeEditCommand.cpp

DEFINITIONS
