/*
 * Copyright (C) 2004, 2008, 2009, 2010 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 "FrameSelection.h"

#include "CharacterData.h"
#include "DeleteSelectionCommand.h"
#include "Document.h"
#include "Editor.h"
#include "EditorClient.h"
#include "Element.h"
#include "EventHandler.h"
#include "ExceptionCode.h"
#include "FloatQuad.h"
#include "FocusController.h"
#include "Frame.h"
#include "FrameTree.h"
#include "FrameView.h"
#include "GraphicsContext.h"
#include "HTMLFormElement.h"
#include "HTMLFrameElementBase.h"
#include "HTMLInputElement.h"
#include "HTMLSelectElement.h"
#include "HTMLNames.h"
#include "HitTestRequest.h"
#include "HitTestResult.h"
#include "InlineTextBox.h"
#include "Page.h"
#include "Range.h"
#include "RenderLayer.h"
#include "RenderText.h"
#include "RenderTextControl.h"
#include "RenderTheme.h"
#include "RenderView.h"
#include "RenderWidget.h"
#include "SecureTextInput.h"
#include "Settings.h"
#include "SpatialNavigation.h"
#include "TextIterator.h"
#include "TypingCommand.h"
#include "htmlediting.h"
#include "visible_units.h"
#include <limits.h>
#include <stdio.h>
#include <wtf/text/CString.h>

#define EDIT_DEBUG 0

namespace WebCore {

using namespace HTMLNames;

static inline LayoutUnit NoXPosForVerticalArrowNavigation()
{
    return std::numeric_limits<LayoutUnit>::min();
}

CaretBase::CaretBase(CaretVisibility visibility)
    : m_caretRectNeedsUpdate(true)
    , m_caretVisibility(visibility)
{
}

DragCaretController::DragCaretController()
    : CaretBase(Visible)
{
}

bool DragCaretController::isContentRichlyEditable() const
{
    return isRichlyEditablePosition(m_position.deepEquivalent());
}

FrameSelection::FrameSelection(Frame* frame)
    : m_frame(frame)
    , m_xPosForVerticalArrowNavigation(NoXPosForVerticalArrowNavigation())
    , m_granularity(CharacterGranularity)
    , m_caretBlinkTimer(this, &FrameSelection::caretBlinkTimerFired)
    , m_absCaretBoundsDirty(true)
    , m_caretPaint(true)
    , m_isCaretBlinkingSuspended(false)
    , m_focused(frame && frame->page() && frame->page()->focusController()->focusedFrame() == frame)
{
}

void FrameSelection::moveTo(const VisiblePosition &pos, EUserTriggered userTriggered, CursorAlignOnScroll align)
{
    SetSelectionOptions options = CloseTyping | ClearTypingStyle | userTriggered;
    setSelection(VisibleSelection(pos.deepEquivalent(), pos.deepEquivalent(), pos.affinity()), options, align);
}

void FrameSelection::moveTo(const VisiblePosition &base, const VisiblePosition &extent, EUserTriggered userTriggered)
{
    SetSelectionOptions options = CloseTyping | ClearTypingStyle | userTriggered;
    setSelection(VisibleSelection(base.deepEquivalent(), extent.deepEquivalent(), base.affinity()), options);
}

void FrameSelection::moveTo(const Position &pos, EAffinity affinity, EUserTriggered userTriggered)
{
    SetSelectionOptions options = CloseTyping | ClearTypingStyle | userTriggered;
    setSelection(VisibleSelection(pos, affinity), options);
}

void FrameSelection::moveTo(const Range *r, EAffinity affinity, EUserTriggered userTriggered)
{
    SetSelectionOptions options = CloseTyping | ClearTypingStyle | userTriggered;
    VisibleSelection selection = r ? VisibleSelection(r->startPosition(), r->endPosition(), affinity) : VisibleSelection(Position(), Position(), affinity);
    setSelection(selection, options);
}

void FrameSelection::moveTo(const Position &base, const Position &extent, EAffinity affinity, EUserTriggered userTriggered)
{
    SetSelectionOptions options = CloseTyping | ClearTypingStyle | userTriggered;
    setSelection(VisibleSelection(base, extent, affinity), options);
}

void DragCaretController::setCaretPosition(const VisiblePosition& position)
{
    if (Node* node = m_position.deepEquivalent().deprecatedNode())
        invalidateCaretRect(node);
    m_position = position;
    setCaretRectNeedsUpdate();
    Document* document = 0;
    if (Node* node = m_position.deepEquivalent().deprecatedNode()) {
        invalidateCaretRect(node);
        document = node->document();
    }
    if (m_position.isNull() || m_position.isOrphan())
        clearCaretRect();
    else
        updateCaretRect(document, m_position);
}

static inline bool shouldAlwaysUseDirectionalSelection(Frame* frame)
{
    return !frame || frame->editor()->behavior().shouldConsiderSelectionAsDirectional();
}

void FrameSelection::setSelection(const VisibleSelection& newSelection, SetSelectionOptions options, CursorAlignOnScroll align, TextGranularity granularity)
{
    bool closeTyping = options & CloseTyping;
    bool shouldClearTypingStyle = options & ClearTypingStyle;
    EUserTriggered userTriggered = selectionOptionsToUserTriggered(options);

    VisibleSelection s = newSelection;
    if (shouldAlwaysUseDirectionalSelection(m_frame))
        s.setIsDirectional(true);

    if (!m_frame) {
        m_selection = s;
        return;
    }

    // <http://bugs.webkit.org/show_bug.cgi?id=23464>: Infinite recursion at FrameSelection::setSelection
    // if document->frame() == m_frame we can get into an infinite loop
    if (s.base().anchorNode()) {
        Document* document = s.base().anchorNode()->document();
        if (document && document->frame() && document->frame() != m_frame && document != m_frame->document()) {
            document->frame()->selection()->setSelection(s, options, align, granularity);
            return;
        }
    }

    m_granularity = granularity;

    if (closeTyping)
        TypingCommand::closeTyping(m_frame->editor()->lastEditCommand());

    if (shouldClearTypingStyle)
        clearTypingStyle();

    if (m_selection == s) {
        // Even if selection was not changed, selection offsets may have been changed.
        notifyRendererOfSelectionChange(userTriggered);
        return;
    }

    VisibleSelection oldSelection = m_selection;

    m_selection = s;
    setCaretRectNeedsUpdate();
    
    if (!s.isNone())
        setFocusedNodeIfNeeded();
    
    updateAppearance();

    // Always clear the x position used for vertical arrow navigation.
    // It will be restored by the vertical arrow navigation code if necessary.
    m_xPosForVerticalArrowNavigation = NoXPosForVerticalArrowNavigation();
    selectFrameElementInParentIfFullySelected();
    notifyRendererOfSelectionChange(userTriggered);
    m_frame->editor()->respondToChangedSelection(oldSelection, options);
    if (userTriggered == UserTriggered) {
        ScrollAlignment alignment;

        if (m_frame->editor()->behavior().shouldCenterAlignWhenSelectionIsRevealed())
            alignment = (align == AlignCursorOnScrollAlways) ? ScrollAlignment::alignCenterAlways : ScrollAlignment::alignCenterIfNeeded;
        else
            alignment = (align == AlignCursorOnScrollAlways) ? ScrollAlignment::alignTopAlways : ScrollAlignment::alignToEdgeIfNeeded;

        revealSelection(alignment, true);
    }

    notifyAccessibilityForSelectionChange();
    m_frame->document()->enqueueDocumentEvent(Event::create(eventNames().selectionchangeEvent, false, false));
}

static bool removingNodeRemovesPosition(Node* node, const Position& position)
{
    if (!position.anchorNode())
        return false;

    if (position.anchorNode() == node)
        return true;

    if (!node->isElementNode())
        return false;

    Element* element = static_cast<Element*>(node);
    return element->contains(position.anchorNode()) || element->contains(position.anchorNode()->shadowAncestorNode());
}

static void clearRenderViewSelection(const Position& position)
{
    RefPtr<Document> document = position.anchorNode()->document();
    document->updateStyleIfNeeded();
    if (RenderView* view = toRenderView(document->renderer()))
        view->clearSelection();
}

void DragCaretController::nodeWillBeRemoved(Node* node)
{
    if (!hasCaret() || (node && !node->inDocument()))
        return;

    if (!removingNodeRemovesPosition(node, m_position.deepEquivalent()))
        return;

    clearRenderViewSelection(m_position.deepEquivalent());
    clear();
}

void FrameSelection::nodeWillBeRemoved(Node* node)
{
    // There can't be a selection inside a fragment, so if a fragment's node is being removed,
    // the selection in the document that created the fragment needs no adjustment.
    if (isNone() || (node && !node->inDocument()))
        return;

    respondToNodeModification(node, removingNodeRemovesPosition(node, m_selection.base()), removingNodeRemovesPosition(node, m_selection.extent()),
        removingNodeRemovesPosition(node, m_selection.start()), removingNodeRemovesPosition(node, m_selection.end()));
}

void FrameSelection::respondToNodeModification(Node* node, bool baseRemoved, bool extentRemoved, bool startRemoved, bool endRemoved)
{
    bool clearRenderTreeSelection = false;
    bool clearDOMTreeSelection = false;

    if (startRemoved || endRemoved) {
        // FIXME: When endpoints are removed, we should just alter the selection, instead of blowing it away.
        clearRenderTreeSelection = true;
        clearDOMTreeSelection = true;
    } else if (baseRemoved || extentRemoved) {
        // The base and/or extent are about to be removed, but the start and end aren't.
        // Change the base and extent to the start and end, but don't re-validate the
        // selection, since doing so could move the start and end into the node
        // that is about to be removed.
        if (m_selection.isBaseFirst())
            m_selection.setWithoutValidation(m_selection.start(), m_selection.end());
        else
            m_selection.setWithoutValidation(m_selection.end(), m_selection.start());
    } else if (RefPtr<Range> range = m_selection.firstRange()) {
        ExceptionCode ec = 0;
        Range::CompareResults compareResult = range->compareNode(node, ec);
        if (!ec && (compareResult == Range::NODE_BEFORE_AND_AFTER || compareResult == Range::NODE_INSIDE)) {
            // If we did nothing here, when this node's renderer was destroyed, the rect that it 
            // occupied would be invalidated, but, selection gaps that change as a result of 
            // the removal wouldn't be invalidated.
            // FIXME: Don't do so much unnecessary invalidation.
            clearRenderTreeSelection = true;
        }
    }

    if (clearRenderTreeSelection)
        clearRenderViewSelection(m_selection.start());

    if (clearDOMTreeSelection)
        setSelection(VisibleSelection(), 0);
}

enum EndPointType { EndPointIsStart, EndPointIsEnd };

static bool shouldRemovePositionAfterAdoptingTextReplacement(Position& position, EndPointType type, CharacterData* node, unsigned offset, unsigned oldLength, unsigned newLength)
{
    if (!position.anchorNode() || position.anchorNode() != node || position.anchorType() != Position::PositionIsOffsetInAnchor)
        return false;

    ASSERT(position.offsetInContainerNode() >= 0);
    unsigned positionOffset = static_cast<unsigned>(position.offsetInContainerNode());
    if (positionOffset > offset && positionOffset < offset + oldLength)
        return true;

    // Adjust the offset if the position is after or at the end of the deleted contents (positionOffset >= offset + oldLength)
    // to avoid having a stale offset except when the position is the end of selection and nothing is deleted, in which case,
    // adjusting offset results in incorrectly extending the selection until the end of newly inserted contents.
    if ((positionOffset > offset + oldLength) || (positionOffset == offset + oldLength && (type == EndPointIsStart || oldLength)))
        position.moveToOffset(positionOffset - oldLength + newLength);

    return false;
}

void FrameSelection::textWillBeReplaced(CharacterData* node, unsigned offset, unsigned oldLength, unsigned newLength)
{
    // The fragment check is a performance optimization. See http://trac.webkit.org/changeset/30062.
    if (isNone() || !node || highestAncestor(node)->nodeType() == Node::DOCUMENT_FRAGMENT_NODE)
        return;

    Position base = m_selection.base();
    Position extent = m_selection.extent();
    Position start = m_selection.start();
    Position end = m_selection.end();
    bool shouldRemoveBase = shouldRemovePositionAfterAdoptingTextReplacement(base, m_selection.isBaseFirst() ? EndPointIsStart : EndPointIsEnd, node, offset, oldLength, newLength);
    bool shouldRemoveExtent = shouldRemovePositionAfterAdoptingTextReplacement(extent, m_selection.isBaseFirst() ? EndPointIsEnd : EndPointIsStart, node, offset, oldLength, newLength);
    bool shouldRemoveStart = shouldRemovePositionAfterAdoptingTextReplacement(start, EndPointIsStart, node, offset, oldLength, newLength);
    bool shouldRemoveEnd = shouldRemovePositionAfterAdoptingTextReplacement(end, EndPointIsEnd, node, offset, oldLength, newLength);

    if ((base != m_selection.base() || extent != m_selection.extent() || start != m_selection.start() || end != m_selection.end())
        && !shouldRemoveStart && !shouldRemoveEnd) {
        VisibleSelection newSelection;
        if (!shouldRemoveBase && !shouldRemoveExtent)
            newSelection.setWithoutValidation(base, extent);
        else {
            if (newSelection.isBaseFirst())
                newSelection.setWithoutValidation(start, end);
            else
                newSelection.setWithoutValidation(end, start);
        }
        m_frame->document()->updateLayout();
        setSelection(newSelection, 0);
        return;
    }

    respondToNodeModification(node, shouldRemoveBase, shouldRemoveExtent, shouldRemoveStart, shouldRemoveEnd);
}

TextDirection FrameSelection::directionOfEnclosingBlock()
{
    return WebCore::directionOfEnclosingBlock(m_selection.extent());
}

void FrameSelection::willBeModified(EAlteration alter, SelectionDirection direction)
{
    if (alter != AlterationExtend)
        return;

    Position start = m_selection.start();
    Position end = m_selection.end();

    bool baseIsStart = true;

    if (m_selection.isDirectional()) {
        // Make base and extent match start and end so we extend the user-visible selection.
        // This only matters for cases where base and extend point to different positions than
        // start and end (e.g. after a double-click to select a word).
        if (m_selection.isBaseFirst())
            baseIsStart = true;
        else
            baseIsStart = false;
    } else {
        switch (direction) {
        case DirectionRight:
            if (directionOfEnclosingBlock() == LTR)
                baseIsStart = true;
            else
                baseIsStart = false;
            break;
        case DirectionForward:
            baseIsStart = true;
            break;
        case DirectionLeft:
            if (directionOfEnclosingBlock() == LTR)
                baseIsStart = false;
            else
                baseIsStart = true;
            break;
        case DirectionBackward:
            baseIsStart = false;
            break;
        }
    }
    if (baseIsStart) {
        m_selection.setBase(start);
        m_selection.setExtent(end);
    } else {
        m_selection.setBase(end);
        m_selection.setExtent(start);
    }
}

VisiblePosition FrameSelection::positionForPlatform(bool isGetStart) const
{
    Settings* settings = m_frame ? m_frame->settings() : 0;
    if (settings && settings->editingBehaviorType() == EditingMacBehavior)
        return isGetStart ? m_selection.visibleStart() : m_selection.visibleEnd();
    // Linux and Windows always extend selections from the extent endpoint.
    // FIXME: VisibleSelection should be fixed to ensure as an invariant that
    // base/extent always point to the same nodes as start/end, but which points
    // to which depends on the value of isBaseFirst. Then this can be changed
    // to just return m_sel.extent().
    return m_selection.isBaseFirst() ? m_selection.visibleEnd() : m_selection.visibleStart();
}

VisiblePosition FrameSelection::startForPlatform() const
{
    return positionForPlatform(true);
}

VisiblePosition FrameSelection::endForPlatform() const
{
    return positionForPlatform(false);
}

VisiblePosition FrameSelection::modifyExtendingRight(TextGranularity granularity)
{
    VisiblePosition pos(m_selection.extent(), m_selection.affinity());

    // The difference between modifyExtendingRight and modifyExtendingForward is:
    // modifyExtendingForward always extends forward logically.
    // modifyExtendingRight behaves the same as modifyExtendingForward except for extending character or word,
    // it extends forward logically if the enclosing block is LTR direction,
    // but it extends backward logically if the enclosing block is RTL direction.
    switch (granularity) {
    case CharacterGranularity:
        if (directionOfEnclosingBlock() == LTR)
            pos = pos.next(CannotCrossEditingBoundary);
        else
            pos = pos.previous(CannotCrossEditingBoundary);
        break;
    case WordGranularity:
        if (directionOfEnclosingBlock() == LTR)
            pos = nextWordPosition(pos);
        else
            pos = previousWordPosition(pos);
        break;
    case LineBoundary:
        if (directionOfEnclosingBlock() == LTR)
            pos = modifyExtendingForward(granularity);
        else
            pos = modifyExtendingBackward(granularity);
        break;
    case SentenceGranularity:
    case LineGranularity:
    case ParagraphGranularity:
    case SentenceBoundary:
    case ParagraphBoundary:
    case DocumentBoundary:
        // FIXME: implement all of the above?
        pos = modifyExtendingForward(granularity);
        break;
    case WebKitVisualWordGranularity:
        break;
    }
    return pos;
}

VisiblePosition FrameSelection::modifyExtendingForward(TextGranularity granularity)
{
    VisiblePosition pos(m_selection.extent(), m_selection.affinity());
    switch (granularity) {
    case CharacterGranularity:
        pos = pos.next(CannotCrossEditingBoundary);
        break;
    case WordGranularity:
        pos = nextWordPosition(pos);
        break;
    case SentenceGranularity:
        pos = nextSentencePosition(pos);
        break;
    case LineGranularity:
        pos = nextLinePosition(pos, lineDirectionPointForBlockDirectionNavigation(EXTENT));
        break;
    case ParagraphGranularity:
        pos = nextParagraphPosition(pos, lineDirectionPointForBlockDirectionNavigation(EXTENT));
        break;
    case SentenceBoundary:
        pos = endOfSentence(endForPlatform());
        break;
    case LineBoundary:
        pos = logicalEndOfLine(endForPlatform());
        break;
    case ParagraphBoundary:
        pos = endOfParagraph(endForPlatform());
        break;
    case DocumentBoundary:
        pos = endForPlatform();
        if (isEditablePosition(pos.deepEquivalent()))
            pos = endOfEditableContent(pos);
        else
            pos = endOfDocument(pos);
        break;
    case WebKitVisualWordGranularity:
        break;
    }
    
    return pos;
}

VisiblePosition FrameSelection::modifyMovingRight(TextGranularity granularity)
{
    VisiblePosition pos;
    switch (granularity) {
    case CharacterGranularity:
        if (isRange()) {
            if (directionOfEnclosingBlock() == LTR)
                pos = VisiblePosition(m_selection.end(), m_selection.affinity());
            else
                pos = VisiblePosition(m_selection.start(), m_selection.affinity());
        } else
            pos = VisiblePosition(m_selection.extent(), m_selection.affinity()).right(true);
        break;
    case WordGranularity:
    case SentenceGranularity:
    case LineGranularity:
    case ParagraphGranularity:
    case SentenceBoundary:
    case ParagraphBoundary:
    case DocumentBoundary:
        // FIXME: Implement all of the above.
        pos = modifyMovingForward(granularity);
        break;
    case LineBoundary:
        pos = rightBoundaryOfLine(startForPlatform(), directionOfEnclosingBlock());
        break;
    case WebKitVisualWordGranularity:
        pos = rightWordPosition(VisiblePosition(m_selection.extent(), m_selection.affinity()));
        break;
    }
    return pos;
}

VisiblePosition FrameSelection::modifyMovingForward(TextGranularity granularity)
{
    VisiblePosition pos;
    // FIXME: Stay in editable content for the less common granularities.
    switch (granularity) {
    case CharacterGranularity:
        if (isRange())
            pos = VisiblePosition(m_selection.end(), m_selection.affinity());
        else
            pos = VisiblePosition(m_selection.extent(), m_selection.affinity()).next(CannotCrossEditingBoundary);
        break;
    case WordGranularity:
        pos = nextWordPosition(VisiblePosition(m_selection.extent(), m_selection.affinity()));
        break;
    case SentenceGranularity:
        pos = nextSentencePosition(VisiblePosition(m_selection.extent(), m_selection.affinity()));
        break;
    case LineGranularity: {
        // down-arrowing from a range selection that ends at the start of a line needs
        // to leave the selection at that line start (no need to call nextLinePosition!)
        pos = endForPlatform();
        if (!isRange() || !isStartOfLine(pos))
            pos = nextLinePosition(pos, lineDirectionPointForBlockDirectionNavigation(START));
        break;
    }
    case ParagraphGranularity:
        pos = nextParagraphPosition(endForPlatform(), lineDirectionPointForBlockDirectionNavigation(START));
        break;
    case SentenceBoundary:
        pos = endOfSentence(endForPlatform());
        break;
    case LineBoundary:
        pos = logicalEndOfLine(endForPlatform());
        break;
    case ParagraphBoundary:
        pos = endOfParagraph(endForPlatform());
        break;
    case DocumentBoundary:
        pos = endForPlatform();
        if (isEditablePosition(pos.deepEquivalent()))
            pos = endOfEditableContent(pos);
        else
            pos = endOfDocument(pos);
        break;
    case WebKitVisualWordGranularity:
        break;
    }
    return pos;
}

VisiblePosition FrameSelection::modifyExtendingLeft(TextGranularity granularity)
{
    VisiblePosition pos(m_selection.extent(), m_selection.affinity());

    // The difference between modifyExtendingLeft and modifyExtendingBackward is:
    // modifyExtendingBackward always extends backward logically.
    // modifyExtendingLeft behaves the same as modifyExtendingBackward except for extending character or word,
    // it extends backward logically if the enclosing block is LTR direction,
    // but it extends forward logically if the enclosing block is RTL direction.
    switch (granularity) {
    case CharacterGranularity:
        if (directionOfEnclosingBlock() == LTR)
            pos = pos.previous(CannotCrossEditingBoundary);
        else
            pos = pos.next(CannotCrossEditingBoundary);
        break;
    case WordGranularity:
        if (directionOfEnclosingBlock() == LTR)
            pos = previousWordPosition(pos);
        else
            pos = nextWordPosition(pos);
        break;
    case LineBoundary:
        if (directionOfEnclosingBlock() == LTR)
            pos = modifyExtendingBackward(granularity);
        else
            pos = modifyExtendingForward(granularity);
        break;
    case SentenceGranularity:
    case LineGranularity:
    case ParagraphGranularity:
    case SentenceBoundary:
    case ParagraphBoundary:
    case DocumentBoundary:
        pos = modifyExtendingBackward(granularity);
        break;
    case WebKitVisualWordGranularity:
        break;
    }
    return pos;
}
       
VisiblePosition FrameSelection::modifyExtendingBackward(TextGranularity granularity)
{
    VisiblePosition pos(m_selection.extent(), m_selection.affinity());

    // Extending a selection backward by word or character from just after a table selects
    // the table.  This "makes sense" from the user perspective, esp. when deleting.
    // It was done here instead of in VisiblePosition because we want VPs to iterate
    // over everything.
    switch (granularity) {
    case CharacterGranularity:
        pos = pos.previous(CannotCrossEditingBoundary);
        break;
    case WordGranularity:
        pos = previousWordPosition(pos);
        break;
    case SentenceGranularity:
        pos = previousSentencePosition(pos);
        break;
    case LineGranularity:
        pos = previousLinePosition(pos, lineDirectionPointForBlockDirectionNavigation(EXTENT));
        break;
    case ParagraphGranularity:
        pos = previousParagraphPosition(pos, lineDirectionPointForBlockDirectionNavigation(EXTENT));
        break;
    case SentenceBoundary:
        pos = startOfSentence(startForPlatform());
        break;
    case LineBoundary:
        pos = logicalStartOfLine(startForPlatform());
        break;
    case ParagraphBoundary:
        pos = startOfParagraph(startForPlatform());
        break;
    case DocumentBoundary:
        pos = startForPlatform();
        if (isEditablePosition(pos.deepEquivalent()))
            pos = startOfEditableContent(pos);
        else
            pos = startOfDocument(pos);
        break;
    case WebKitVisualWordGranularity:
        break;
    }
    return pos;
}

VisiblePosition FrameSelection::modifyMovingLeft(TextGranularity granularity)
{
    VisiblePosition pos;
    switch (granularity) {
    case CharacterGranularity:
        if (isRange())
            if (directionOfEnclosingBlock() == LTR)
                pos = VisiblePosition(m_selection.start(), m_selection.affinity());
            else
                pos = VisiblePosition(m_selection.end(), m_selection.affinity());
        else
            pos = VisiblePosition(m_selection.extent(), m_selection.affinity()).left(true);
        break;
    case WordGranularity:
    case SentenceGranularity:
    case LineGranularity:
    case ParagraphGranularity:
    case SentenceBoundary:
    case ParagraphBoundary:
    case DocumentBoundary:
        // FIXME: Implement all of the above.
        pos = modifyMovingBackward(granularity);
        break;
    case LineBoundary:
        pos = leftBoundaryOfLine(startForPlatform(), directionOfEnclosingBlock());
        break;
    case WebKitVisualWordGranularity:
        pos = leftWordPosition(VisiblePosition(m_selection.extent(), m_selection.affinity()));
        break;
    }
    return pos;
}

VisiblePosition FrameSelection::modifyMovingBackward(TextGranularity granularity)
{
    VisiblePosition pos;
    switch (granularity) {
    case CharacterGranularity:
        if (isRange())
            pos = VisiblePosition(m_selection.start(), m_selection.affinity());
        else
            pos = VisiblePosition(m_selection.extent(), m_selection.affinity()).previous(CannotCrossEditingBoundary);
        break;
    case WordGranularity:
        pos = previousWordPosition(VisiblePosition(m_selection.extent(), m_selection.affinity()));
        break;
    case SentenceGranularity:
        pos = previousSentencePosition(VisiblePosition(m_selection.extent(), m_selection.affinity()));
        break;
    case LineGranularity:
        pos = previousLinePosition(startForPlatform(), lineDirectionPointForBlockDirectionNavigation(START));
        break;
    case ParagraphGranularity:
        pos = previousParagraphPosition(startForPlatform(), lineDirectionPointForBlockDirectionNavigation(START));
        break;
    case SentenceBoundary:
        pos = startOfSentence(startForPlatform());
        break;
    case LineBoundary:
        pos = logicalStartOfLine(startForPlatform());
        break;
    case ParagraphBoundary:
        pos = startOfParagraph(startForPlatform());
        break;
    case DocumentBoundary:
        pos = startForPlatform();
        if (isEditablePosition(pos.deepEquivalent()))
            pos = startOfEditableContent(pos);
        else
            pos = startOfDocument(pos);
        break;
    case WebKitVisualWordGranularity:
        break;
    }
    return pos;
}

static bool isBoundary(TextGranularity granularity)
{
    return granularity == LineBoundary || granularity == ParagraphBoundary || granularity == DocumentBoundary;
}    

bool FrameSelection::modify(EAlteration alter, SelectionDirection direction, TextGranularity granularity, EUserTriggered userTriggered)
{
    if (userTriggered == UserTriggered) {
        FrameSelection trialFrameSelection;
        trialFrameSelection.setSelection(m_selection);
        trialFrameSelection.modify(alter, direction, granularity, NotUserTriggered);

        bool change = shouldChangeSelection(trialFrameSelection.selection());
        if (!change)
            return false;
    }

    willBeModified(alter, direction);

    bool wasRange = m_selection.isRange();
    Position originalStartPosition = m_selection.start();
    VisiblePosition position;
    switch (direction) {
    case DirectionRight:
        if (alter == AlterationMove)
            position = modifyMovingRight(granularity);
        else
            position = modifyExtendingRight(granularity);
        break;
    case DirectionForward:
        if (alter == AlterationExtend)
            position = modifyExtendingForward(granularity);
        else
            position = modifyMovingForward(granularity);
        break;
    case DirectionLeft:
        if (alter == AlterationMove)
            position = modifyMovingLeft(granularity);
        else
            position = modifyExtendingLeft(granularity);
        break;
    case DirectionBackward:
        if (alter == AlterationExtend)
            position = modifyExtendingBackward(granularity);
        else
            position = modifyMovingBackward(granularity);
        break;
    }

    if (position.isNull())
        return false;

    if (isSpatialNavigationEnabled(m_frame))
        if (!wasRange && alter == AlterationMove && position == originalStartPosition)
            return false;

    // Some of the above operations set an xPosForVerticalArrowNavigation.
    // Setting a selection will clear it, so save it to possibly restore later.
    // Note: the START position type is arbitrary because it is unused, it would be
    // the requested position type if there were no xPosForVerticalArrowNavigation set.
    LayoutUnit x = lineDirectionPointForBlockDirectionNavigation(START);

    switch (alter) {
    case AlterationMove:
        moveTo(position, userTriggered);
        break;
    case AlterationExtend:
        // Standard Mac behavior when extending to a boundary is grow the selection rather than leaving the
        // base in place and moving the extent. Matches NSTextView.
        if (!m_frame || !m_frame->editor()->behavior().shouldAlwaysGrowSelectionWhenExtendingToBoundary() || m_selection.isCaret() || !isBoundary(granularity))
            setExtent(position, userTriggered);
        else {
            TextDirection textDirection = directionOfEnclosingBlock();
            if (direction == DirectionForward || (textDirection == LTR && direction == DirectionRight) || (textDirection == RTL && direction == DirectionLeft))
                setEnd(position, userTriggered);
            else
                setStart(position, userTriggered);
        }
        break;
    }
    
    if (granularity == LineGranularity || granularity == ParagraphGranularity)
        m_xPosForVerticalArrowNavigation = x;

    if (userTriggered == UserTriggered)
        m_granularity = CharacterGranularity;


    setCaretRectNeedsUpdate();

    m_selection.setIsDirectional(shouldAlwaysUseDirectionalSelection(m_frame) || alter == AlterationExtend);

    return true;
}

// FIXME: Maybe baseline would be better?
static bool absoluteCaretY(const VisiblePosition &c, LayoutUnit &y)
{
    LayoutRect rect = c.absoluteCaretBounds();
    if (rect.isEmpty())
        return false;
    y = rect.y() + rect.height() / 2;
    return true;
}

bool FrameSelection::modify(EAlteration alter, unsigned verticalDistance, VerticalDirection direction, EUserTriggered userTriggered, CursorAlignOnScroll align)
{
    if (!verticalDistance)
        return false;

    if (userTriggered == UserTriggered) {
        FrameSelection trialFrameSelection;
        trialFrameSelection.setSelection(m_selection);
        trialFrameSelection.modify(alter, verticalDistance, direction, NotUserTriggered);

        bool change = shouldChangeSelection(trialFrameSelection.selection());
        if (!change)
            return false;
    }

    willBeModified(alter, direction == DirectionUp ? DirectionBackward : DirectionForward);

    VisiblePosition pos;
    LayoutUnit xPos = 0;
    switch (alter) {
    case AlterationMove:
        pos = VisiblePosition(direction == DirectionUp ? m_selection.start() : m_selection.end(), m_selection.affinity());
        xPos = lineDirectionPointForBlockDirectionNavigation(direction == DirectionUp ? START : END);
        m_selection.setAffinity(direction == DirectionUp ? UPSTREAM : DOWNSTREAM);
        break;
    case AlterationExtend:
        pos = VisiblePosition(m_selection.extent(), m_selection.affinity());
        xPos = lineDirectionPointForBlockDirectionNavigation(EXTENT);
        m_selection.setAffinity(DOWNSTREAM);
        break;
    }

    LayoutUnit startY;
    if (!absoluteCaretY(pos, startY))
        return false;
    if (direction == DirectionUp)
        startY = -startY;
    LayoutUnit lastY = startY;

    VisiblePosition result;
    VisiblePosition next;
    for (VisiblePosition p = pos; ; p = next) {
        next = (direction == DirectionUp ? previousLinePosition : nextLinePosition)(p, xPos);
        if (next.isNull() || next == p)
            break;
        LayoutUnit nextY;
        if (!absoluteCaretY(next, nextY))
            break;
        if (direction == DirectionUp)
            nextY = -nextY;
        if (nextY - startY > static_cast<LayoutUnit>(verticalDistance))
            break;
        if (nextY >= lastY) {
            lastY = nextY;
            result = next;
        }
    }

    if (result.isNull())
        return false;

    switch (alter) {
    case AlterationMove:
        moveTo(result, userTriggered, align);
        break;
    case AlterationExtend:
        setExtent(result, userTriggered);
        break;
    }

    if (userTriggered == UserTriggered)
        m_granularity = CharacterGranularity;

    m_selection.setIsDirectional(shouldAlwaysUseDirectionalSelection(m_frame) || alter == AlterationExtend);

    return true;
}

LayoutUnit FrameSelection::lineDirectionPointForBlockDirectionNavigation(EPositionType type)
{
    LayoutUnit x = 0;

    if (isNone())
        return x;

    Position pos;
    switch (type) {
    case START:
        pos = m_selection.start();
        break;
    case END:
        pos = m_selection.end();
        break;
    case BASE:
        pos = m_selection.base();
        break;
    case EXTENT:
        pos = m_selection.extent();
        break;
    }

    Frame* frame = pos.anchorNode()->document()->frame();
    if (!frame)
        return x;
        
    if (m_xPosForVerticalArrowNavigation == NoXPosForVerticalArrowNavigation()) {
        VisiblePosition visiblePosition(pos, m_selection.affinity());
        // VisiblePosition creation can fail here if a node containing the selection becomes visibility:hidden
        // after the selection is created and before this function is called.
        x = visiblePosition.isNotNull() ? visiblePosition.lineDirectionPointForBlockDirectionNavigation() : 0;
        m_xPosForVerticalArrowNavigation = x;
    } else
        x = m_xPosForVerticalArrowNavigation;
        
    return x;
}

void FrameSelection::clear()
{
    m_granularity = CharacterGranularity;
    setSelection(VisibleSelection());
}

void FrameSelection::setStart(const VisiblePosition &pos, EUserTriggered trigger)
{
    if (m_selection.isBaseFirst())
        setBase(pos, trigger);
    else
        setExtent(pos, trigger);
}

void FrameSelection::setEnd(const VisiblePosition &pos, EUserTriggered trigger)
{
    if (m_selection.isBaseFirst())
        setExtent(pos, trigger);
    else
        setBase(pos, trigger);
}

void FrameSelection::setBase(const VisiblePosition &pos, EUserTriggered userTriggered)
{
    setSelection(VisibleSelection(pos.deepEquivalent(), m_selection.extent(), pos.affinity()), CloseTyping | ClearTypingStyle | userTriggered);
}

void FrameSelection::setExtent(const VisiblePosition &pos, EUserTriggered userTriggered)
{
    setSelection(VisibleSelection(m_selection.base(), pos.deepEquivalent(), pos.affinity()), CloseTyping | ClearTypingStyle | userTriggered);
}

void FrameSelection::setBase(const Position &pos, EAffinity affinity, EUserTriggered userTriggered)
{
    setSelection(VisibleSelection(pos, m_selection.extent(), affinity), CloseTyping | ClearTypingStyle | userTriggered);
}

void FrameSelection::setExtent(const Position &pos, EAffinity affinity, EUserTriggered userTriggered)
{
    setSelection(VisibleSelection(m_selection.base(), pos, affinity), CloseTyping | ClearTypingStyle | userTriggered);
}

void CaretBase::clearCaretRect()
{
    m_caretLocalRect = LayoutRect();
}

bool CaretBase::updateCaretRect(Document* document, const VisiblePosition& caretPosition)
{
    document->updateStyleIfNeeded();
    m_caretLocalRect = LayoutRect();

    m_caretRectNeedsUpdate = false;

    if (caretPosition.isNull())
        return false;

    ASSERT(caretPosition.deepEquivalent().deprecatedNode()->renderer());

    // First compute a rect local to the renderer at the selection start.
    RenderObject* renderer;
    LayoutRect localRect = caretPosition.localCaretRect(renderer);

    // Get the renderer that will be responsible for painting the caret
    // (which is either the renderer we just found, or one of its containers).
    RenderObject* caretPainter = caretRenderer(caretPosition.deepEquivalent().deprecatedNode());

    // Compute an offset between the renderer and the caretPainter.
    bool unrooted = false;
    while (renderer != caretPainter) {
        RenderObject* containerObject = renderer->container();
        if (!containerObject) {
            unrooted = true;
            break;
        }
        localRect.move(renderer->offsetFromContainer(containerObject, localRect.location()));
        renderer = containerObject;
    }

    if (!unrooted)
        m_caretLocalRect = localRect;

    return true;
}

static inline bool caretRendersInsideNode(Node* node)
{
    return node && !isTableElement(node) && !editingIgnoresContent(node);
}

RenderObject* CaretBase::caretRenderer(Node* node) const
{
    if (!node)
        return 0;

    RenderObject* renderer = node->renderer();
    if (!renderer)
        return 0;

    // if caretNode is a block and caret is inside it then caret should be painted by that block
    bool paintedByBlock = renderer->isBlockFlow() && caretRendersInsideNode(node);
    return paintedByBlock ? renderer : renderer->containingBlock();
}

RenderObject* FrameSelection::caretRenderer() const
{
    return CaretBase::caretRenderer(m_selection.start().deprecatedNode());
}

RenderObject* DragCaretController::caretRenderer() const
{
    return CaretBase::caretRenderer(m_position.deepEquivalent().deprecatedNode());
}

LayoutRect FrameSelection::localCaretRect()
{
    if (shouldUpdateCaretRect()) {
        if (!isCaret() || m_selection.start().isOrphan() || m_selection.end().isOrphan())
            clearCaretRect();
        else if (updateCaretRect(m_frame->document(), VisiblePosition(m_selection.start(), m_selection.affinity())))
            m_absCaretBoundsDirty = true;
    }

    return localCaretRectWithoutUpdate();
}

LayoutRect CaretBase::absoluteBoundsForLocalRect(Node* node, const LayoutRect& rect) const
{
    RenderObject* caretPainter = caretRenderer(node);
    if (!caretPainter)
        return LayoutRect();
    
    LayoutRect localRect(rect);
    if (caretPainter->isBox())
        toRenderBox(caretPainter)->flipForWritingMode(localRect);
    return caretPainter->localToAbsoluteQuad(FloatRect(localRect)).enclosingBoundingBox();
}

LayoutRect FrameSelection::absoluteCaretBounds()
{
    recomputeCaretRect();
    return m_absCaretBounds;
}

static LayoutRect repaintRectForCaret(LayoutRect caret)
{
    if (caret.isEmpty())
        return LayoutRect();
    // Ensure that the dirty rect intersects the block that paints the caret even in the case where
    // the caret itself is just outside the block. See <https://bugs.webkit.org/show_bug.cgi?id=19086>.
    caret.inflateX(1);
    return caret;
}

LayoutRect CaretBase::caretRepaintRect(Node* node) const
{
    return absoluteBoundsForLocalRect(node, repaintRectForCaret(localCaretRectWithoutUpdate()));
}

bool FrameSelection::recomputeCaretRect()
{
    if (!shouldUpdateCaretRect())
        return false;

    if (!m_frame)
        return false;

    FrameView* v = m_frame->document()->view();
    if (!v)
        return false;

    LayoutRect oldRect = localCaretRectWithoutUpdate();
    LayoutRect newRect = localCaretRect();
    if (oldRect == newRect && !m_absCaretBoundsDirty)
        return false;

    LayoutRect oldAbsCaretBounds = m_absCaretBounds;
    // FIXME: Rename m_caretRect to m_localCaretRect.
    m_absCaretBounds = absoluteBoundsForLocalRect(m_selection.start().deprecatedNode(), localCaretRectWithoutUpdate());
    m_absCaretBoundsDirty = false;
    
    if (oldAbsCaretBounds == m_absCaretBounds)
        return false;
        
    LayoutRect oldAbsoluteCaretRepaintBounds = m_absoluteCaretRepaintBounds;
    // We believe that we need to inflate the local rect before transforming it to obtain the repaint bounds.
    m_absoluteCaretRepaintBounds = caretRepaintRect(m_selection.start().deprecatedNode());

#if ENABLE(TEXT_CARET)    
    if (RenderView* view = toRenderView(m_frame->document()->renderer())) {
        // FIXME: make caret repainting container-aware.
        view->repaintRectangleInViewAndCompositedLayers(oldAbsoluteCaretRepaintBounds, false);
        if (shouldRepaintCaret(view, isContentEditable()))
            view->repaintRectangleInViewAndCompositedLayers(m_absoluteCaretRepaintBounds, false);
    }
#endif
    return true;
}

bool CaretBase::shouldRepaintCaret(const RenderView* view, bool isContentEditable) const
{
    ASSERT(view);
    Frame* frame = view->frameView() ? view->frameView()->frame() : 0; // The frame where the selection started.
    bool caretBrowsing = frame && frame->settings() && frame->settings()->caretBrowsingEnabled();
    return (caretBrowsing || isContentEditable);
}

void FrameSelection::invalidateCaretRect()
{
    if (!isCaret())
        return;

    CaretBase::invalidateCaretRect(m_selection.start().deprecatedNode(), recomputeCaretRect());
}

void CaretBase::invalidateCaretRect(Node* node, bool caretRectChanged)
{
    // EDIT FIXME: This is an unfortunate hack.
    // Basically, we can't trust this layout position since we 
    // can't guarantee that the check to see if we are in unrendered 
    // content will work at this point. We may have to wait for
    // a layout and re-render of the document to happen. So, resetting this
    // flag will cause another caret layout to happen the first time
    // that we try to paint the caret after this call. That one will work since
    // it happens after the document has accounted for any editing
    // changes which may have been done.
    // And, we need to leave this layout here so the caret moves right 
    // away after clicking.
    m_caretRectNeedsUpdate = true;

    if (!caretRectChanged) {
        RenderView* view = toRenderView(node->document()->renderer());
        if (view && shouldRepaintCaret(view, node->isContentEditable()))
            view->repaintRectangleInViewAndCompositedLayers(caretRepaintRect(node), false);
    }
}

void FrameSelection::paintCaret(GraphicsContext* context, const LayoutPoint& paintOffset, const LayoutRect& clipRect)
{
    if (m_selection.isCaret() && m_caretPaint)
        CaretBase::paintCaret(m_selection.start().deprecatedNode(), context, paintOffset, clipRect);
}

void CaretBase::paintCaret(Node* node, GraphicsContext* context, const LayoutPoint& paintOffset, const LayoutRect& clipRect) const
{
#if ENABLE(TEXT_CARET)
    if (m_caretVisibility == Hidden)
        return;

    LayoutRect drawingRect = localCaretRectWithoutUpdate();
    RenderObject* renderer = caretRenderer(node);
    if (renderer && renderer->isBox())
        toRenderBox(renderer)->flipForWritingMode(drawingRect);
    drawingRect.moveBy(paintOffset);
    LayoutRect caret = intersection(drawingRect, clipRect);
    if (caret.isEmpty())
        return;

    Color caretColor = Color::black;
    ColorSpace colorSpace = ColorSpaceDeviceRGB;
    Element* element = node->rootEditableElement();
    if (element && element->renderer()) {
        caretColor = element->renderer()->style()->visitedDependentColor(CSSPropertyColor);
        colorSpace = element->renderer()->style()->colorSpace();
    }

    context->fillRect(caret, caretColor, colorSpace);
#else
    UNUSED_PARAM(node);
    UNUSED_PARAM(context);
    UNUSED_PARAM(paintOffset);
    UNUSED_PARAM(clipRect);
#endif
}

void FrameSelection::debugRenderer(RenderObject *r, bool selected) const
{
    if (r->node()->isElementNode()) {
        Element* element = static_cast<Element *>(r->node());
        fprintf(stderr, "%s%s\n", selected ? "==> " : "    ", element->localName().string().utf8().data());
    } else if (r->isText()) {
        RenderText* textRenderer = toRenderText(r);
        if (!textRenderer->textLength() || !textRenderer->firstTextBox()) {
            fprintf(stderr, "%s#text (empty)\n", selected ? "==> " : "    ");
            return;
        }
        
        static const int max = 36;
        String text = textRenderer->text();
        int textLength = text.length();
        if (selected) {
            int offset = 0;
            if (r->node() == m_selection.start().containerNode())
                offset = m_selection.start().computeOffsetInContainerNode();
            else if (r->node() == m_selection.end().containerNode())
                offset = m_selection.end().computeOffsetInContainerNode();

            int pos;
            InlineTextBox* box = textRenderer->findNextInlineTextBox(offset, pos);
            text = text.substring(box->start(), box->len());
            
            String show;
            int mid = max / 2;
            int caret = 0;
            
            // text is shorter than max
            if (textLength < max) {
                show = text;
                caret = pos;
            } else if (pos - mid < 0) {
                // too few characters to left
                show = text.left(max - 3) + "...";
                caret = pos;
            } else if (pos - mid >= 0 && pos + mid <= textLength) {
                // enough characters on each side
                show = "..." + text.substring(pos - mid + 3, max - 6) + "...";
                caret = mid;
            } else {
                // too few characters on right
                show = "..." + text.right(max - 3);
                caret = pos - (textLength - show.length());
            }
            
            show.replace('\n', ' ');
            show.replace('\r', ' ');
            fprintf(stderr, "==> #text : \"%s\" at offset %d\n", show.utf8().data(), pos);
            fprintf(stderr, "           ");
            for (int i = 0; i < caret; i++)
                fprintf(stderr, " ");
            fprintf(stderr, "^\n");
        } else {
            if ((int)text.length() > max)
                text = text.left(max - 3) + "...";
            else
                text = text.left(max);
            fprintf(stderr, "    #text : \"%s\"\n", text.utf8().data());
        }
    }
}

bool FrameSelection::contains(const LayoutPoint& point)
{
    Document* document = m_frame->document();
    
    // Treat a collapsed selection like no selection.
    if (!isRange())
        return false;
    if (!document->renderer()) 
        return false;
    
    HitTestRequest request(HitTestRequest::ReadOnly |
                           HitTestRequest::Active);
    HitTestResult result(point);
    document->renderView()->layer()->hitTest(request, result);
    Node* innerNode = result.innerNode();
    if (!innerNode || !innerNode->renderer())
        return false;
    
    VisiblePosition visiblePos(innerNode->renderer()->positionForPoint(result.localPoint()));
    if (visiblePos.isNull())
        return false;
        
    if (m_selection.visibleStart().isNull() || m_selection.visibleEnd().isNull())
        return false;
        
    Position start(m_selection.visibleStart().deepEquivalent());
    Position end(m_selection.visibleEnd().deepEquivalent());
    Position p(visiblePos.deepEquivalent());

    return comparePositions(start, p) <= 0 && comparePositions(p, end) <= 0;
}

// Workaround for the fact that it's hard to delete a frame.
// Call this after doing user-triggered selections to make it easy to delete the frame you entirely selected.
// Can't do this implicitly as part of every setSelection call because in some contexts it might not be good
// for the focus to move to another frame. So instead we call it from places where we are selecting with the
// mouse or the keyboard after setting the selection.
void FrameSelection::selectFrameElementInParentIfFullySelected()
{
    // Find the parent frame; if there is none, then we have nothing to do.
    Frame* parent = m_frame->tree()->parent();
    if (!parent)
        return;
    Page* page = m_frame->page();
    if (!page)
        return;

    // Check if the selection contains the entire frame contents; if not, then there is nothing to do.
    if (!isRange())
        return;
    if (!isStartOfDocument(selection().visibleStart()))
        return;
    if (!isEndOfDocument(selection().visibleEnd()))
        return;

    // Get to the <iframe> or <frame> (or even <object>) element in the parent frame.
    Element* ownerElement = m_frame->ownerElement();
    if (!ownerElement)
        return;
    ContainerNode* ownerElementParent = ownerElement->parentNode();
    if (!ownerElementParent)
        return;
        
    // This method's purpose is it to make it easier to select iframes (in order to delete them).  Don't do anything if the iframe isn't deletable.
    if (!ownerElementParent->rendererIsEditable())
        return;

    // Create compute positions before and after the element.
    unsigned ownerElementNodeIndex = ownerElement->nodeIndex();
    VisiblePosition beforeOwnerElement(VisiblePosition(Position(ownerElementParent, ownerElementNodeIndex, Position::PositionIsOffsetInAnchor)));
    VisiblePosition afterOwnerElement(VisiblePosition(Position(ownerElementParent, ownerElementNodeIndex + 1, Position::PositionIsOffsetInAnchor), VP_UPSTREAM_IF_POSSIBLE));

    // Focus on the parent frame, and then select from before this element to after.
    VisibleSelection newSelection(beforeOwnerElement, afterOwnerElement);
    if (parent->selection()->shouldChangeSelection(newSelection)) {
        page->focusController()->setFocusedFrame(parent);
        parent->selection()->setSelection(newSelection);
    }
}

void FrameSelection::selectAll()
{
    Document* document = m_frame->document();

    if (document->focusedNode() && document->focusedNode()->hasTagName(selectTag)) {
        HTMLSelectElement* selectElement = static_cast<HTMLSelectElement*>(document->focusedNode());
        if (selectElement->canSelectAll()) {
            selectElement->selectAll();
            return;
        }
    }

    RefPtr<Node> root = 0;
    Node* selectStartTarget = 0;
    if (isContentEditable()) {
        root = highestEditableRoot(m_selection.start());
        if (Node* shadowRoot = m_selection.nonBoundaryShadowTreeRootNode())
            selectStartTarget = shadowRoot->shadowAncestorNode();
        else
            selectStartTarget = root.get();
    } else {
        root = m_selection.nonBoundaryShadowTreeRootNode();
        if (root)
            selectStartTarget = root->shadowAncestorNode();
        else {
            root = document->documentElement();
            selectStartTarget = document->body();
        }
    }
    if (!root)
        return;

    if (selectStartTarget && !selectStartTarget->dispatchEvent(Event::create(eventNames().selectstartEvent, true, true)))
        return;

    VisibleSelection newSelection(VisibleSelection::selectionFromContentsOfNode(root.get()));

    if (shouldChangeSelection(newSelection))
        setSelection(newSelection);

    selectFrameElementInParentIfFullySelected();
    notifyRendererOfSelectionChange(UserTriggered);
}

bool FrameSelection::setSelectedRange(Range* range, EAffinity affinity, bool closeTyping)
{
    if (!range || !range->startContainer() || !range->endContainer())
        return false;
    ASSERT(range->startContainer()->document() == range->endContainer()->document());

    m_frame->document()->updateLayoutIgnorePendingStylesheets();

    // Non-collapsed ranges are not allowed to start at the end of a line that is wrapped,
    // they start at the beginning of the next line instead
    ExceptionCode ec = 0;
    bool collapsed = range->collapsed(ec);
    if (ec)
        return false;

    // FIXME: Can we provide extentAffinity?
    VisiblePosition visibleStart(range->startPosition(), collapsed ? affinity : DOWNSTREAM);
    VisiblePosition visibleEnd(range->endPosition(), SEL_DEFAULT_AFFINITY);
    setSelection(VisibleSelection(visibleStart, visibleEnd), ClearTypingStyle | (closeTyping ? CloseTyping : 0));
    return true;
}

bool FrameSelection::isInPasswordField() const
{
    HTMLTextFormControlElement* textControl = enclosingTextFormControl(start());
    return textControl && textControl->hasTagName(inputTag) && static_cast<HTMLInputElement*>(textControl)->isPasswordField();
}

void FrameSelection::focusedOrActiveStateChanged()
{
    bool activeAndFocused = isFocusedAndActive();

    // Because RenderObject::selectionBackgroundColor() and
    // RenderObject::selectionForegroundColor() check if the frame is active,
    // we have to update places those colors were painted.
    if (RenderView* view = toRenderView(m_frame->document()->renderer()))
        view->repaintRectangleInViewAndCompositedLayers(enclosingIntRect(bounds()));

    // Caret appears in the active frame.
    if (activeAndFocused)
        setSelectionFromNone();
    setCaretVisibility(activeAndFocused ? Visible : Hidden);

    // Update for caps lock state
    m_frame->eventHandler()->capsLockStateMayHaveChanged();

    // Because CSSStyleSelector::checkOneSelector() and
    // RenderTheme::isFocused() check if the frame is active, we have to
    // update style and theme state that depended on those.
    if (Node* node = m_frame->document()->focusedNode()) {
        node->setNeedsStyleRecalc();
        if (RenderObject* renderer = node->renderer())
            if (renderer && renderer->style()->hasAppearance())
                renderer->theme()->stateChanged(renderer, FocusState);
    }

    // Secure keyboard entry is set by the active frame.
    if (m_frame->document()->useSecureKeyboardEntryWhenActive())
        setUseSecureKeyboardEntry(activeAndFocused);
}

void FrameSelection::pageActivationChanged()
{
    focusedOrActiveStateChanged();
}

void FrameSelection::updateSecureKeyboardEntryIfActive()
{
    if (m_frame->document() && isFocusedAndActive())
        setUseSecureKeyboardEntry(m_frame->document()->useSecureKeyboardEntryWhenActive());
}

void FrameSelection::setUseSecureKeyboardEntry(bool enable)
{
    if (enable)
        enableSecureTextInput();
    else
        disableSecureTextInput();
}

void FrameSelection::setFocused(bool flag)
{
    if (m_focused == flag)
        return;
    m_focused = flag;

    focusedOrActiveStateChanged();
}

bool FrameSelection::isFocusedAndActive() const
{
    return m_focused && m_frame->page() && m_frame->page()->focusController()->isActive();
}

void FrameSelection::updateAppearance()
{
#if ENABLE(TEXT_CARET)
    bool caretRectChanged = recomputeCaretRect();

    bool caretBrowsing = m_frame->settings() && m_frame->settings()->caretBrowsingEnabled();
    bool shouldBlink = caretIsVisible() && isCaret() && (isContentEditable() || caretBrowsing);

    // If the caret moved, stop the blink timer so we can restart with a
    // black caret in the new location.
    if (caretRectChanged || !shouldBlink)
        m_caretBlinkTimer.stop();

    // Start blinking with a black caret. Be sure not to restart if we're
    // already blinking in the right location.
    if (shouldBlink && !m_caretBlinkTimer.isActive()) {
        if (double blinkInterval = m_frame->page()->theme()->caretBlinkInterval())
            m_caretBlinkTimer.startRepeating(blinkInterval);

        if (!m_caretPaint) {
            m_caretPaint = true;
            invalidateCaretRect();
        }
    }
#endif

    // We need to update style in case the node containing the selection is made display:none.
    m_frame->document()->updateStyleIfNeeded();

    RenderView* view = m_frame->contentRenderer();
    if (!view)
        return;

    VisibleSelection selection = this->selection();

    if (!selection.isRange()) {
        view->clearSelection();
        return;
    }

    // Use the rightmost candidate for the start of the selection, and the leftmost candidate for the end of the selection.
    // Example: foo <a>bar</a>.  Imagine that a line wrap occurs after 'foo', and that 'bar' is selected.   If we pass [foo, 3]
    // as the start of the selection, the selection painting code will think that content on the line containing 'foo' is selected
    // and will fill the gap before 'bar'.
    Position startPos = selection.start();
    Position candidate = startPos.downstream();
    if (candidate.isCandidate())
        startPos = candidate;
    Position endPos = selection.end();
    candidate = endPos.upstream();
    if (candidate.isCandidate())
        endPos = candidate;

    // We can get into a state where the selection endpoints map to the same VisiblePosition when a selection is deleted
    // because we don't yet notify the FrameSelection of text removal.
    if (startPos.isNotNull() && endPos.isNotNull() && selection.visibleStart() != selection.visibleEnd()) {
        RenderObject* startRenderer = startPos.deprecatedNode()->renderer();
        RenderObject* endRenderer = endPos.deprecatedNode()->renderer();
        view->setSelection(startRenderer, startPos.deprecatedEditingOffset(), endRenderer, endPos.deprecatedEditingOffset());
    }
}

void FrameSelection::setCaretVisibility(CaretVisibility visibility)
{
    if (caretVisibility() == visibility)
        return;
    clearCaretRectIfNeeded();
    CaretBase::setCaretVisibility(visibility);
    updateAppearance();
}

void FrameSelection::clearCaretRectIfNeeded()
{
#if ENABLE(TEXT_CARET)
    if (!m_caretPaint)
        return;
    m_caretPaint = false;
    invalidateCaretRect();
#endif
}

void FrameSelection::caretBlinkTimerFired(Timer<FrameSelection>*)
{
#if ENABLE(TEXT_CARET)
    ASSERT(caretIsVisible());
    ASSERT(isCaret());
    bool caretPaint = m_caretPaint;
    if (isCaretBlinkingSuspended() && caretPaint)
        return;
    m_caretPaint = !caretPaint;
    invalidateCaretRect();
#endif
}

void FrameSelection::notifyRendererOfSelectionChange(EUserTriggered userTriggered)
{
    m_frame->document()->updateStyleIfNeeded();

    if (!rootEditableElement())
        return;

    if (HTMLTextFormControlElement* textControl = enclosingTextFormControl(start()))
        textControl->selectionChanged(userTriggered == UserTriggered);
}

// Helper function that tells whether a particular node is an element that has an entire
// Frame and FrameView, a <frame>, <iframe>, or <object>.
static bool isFrameElement(const Node* n)
{
    if (!n)
        return false;
    RenderObject* renderer = n->renderer();
    if (!renderer || !renderer->isWidget())
        return false;
    Widget* widget = toRenderWidget(renderer)->widget();
    return widget && widget->isFrameView();
}

void FrameSelection::setFocusedNodeIfNeeded()
{
    if (isNone() || !isFocused())
        return;

    bool caretBrowsing = m_frame->settings() && m_frame->settings()->caretBrowsingEnabled();
    if (caretBrowsing) {
        if (Node* anchor = enclosingAnchorElement(base())) {
            m_frame->page()->focusController()->setFocusedNode(anchor, m_frame);
            return;
        }
    }

    if (Node* target = rootEditableElement()) {
        // Walk up the DOM tree to search for a node to focus. 
        while (target) {
            // We don't want to set focus on a subframe when selecting in a parent frame,
            // so add the !isFrameElement check here. There's probably a better way to make this
            // work in the long term, but this is the safest fix at this time.
            if (target && target->isMouseFocusable() && !isFrameElement(target)) {
                m_frame->page()->focusController()->setFocusedNode(target, m_frame);
                return;
            }
            target = target->parentOrHostNode(); 
        }
        m_frame->document()->setFocusedNode(0);
    }

    if (caretBrowsing)
        m_frame->page()->focusController()->setFocusedNode(0, m_frame);
}

void DragCaretController::paintDragCaret(Frame* frame, GraphicsContext* p, const LayoutPoint& paintOffset, const LayoutRect& clipRect) const
{
#if ENABLE(TEXT_CARET)
    if (m_position.deepEquivalent().deprecatedNode()->document()->frame() == frame)
        paintCaret(m_position.deepEquivalent().deprecatedNode(), p, paintOffset, clipRect);
#else
    UNUSED_PARAM(frame);
    UNUSED_PARAM(p);
    UNUSED_PARAM(paintOffset);
    UNUSED_PARAM(clipRect);
#endif
}

PassRefPtr<CSSMutableStyleDeclaration> FrameSelection::copyTypingStyle() const
{
    if (!m_typingStyle || !m_typingStyle->style())
        return 0;
    return m_typingStyle->style()->copy();
}

bool FrameSelection::shouldDeleteSelection(const VisibleSelection& selection) const
{
    return m_frame->editor()->client()->shouldDeleteRange(selection.toNormalizedRange().get());
}

FloatRect FrameSelection::bounds(bool clipToVisibleContent) const
{
    RenderView* root = m_frame->contentRenderer();
    FrameView* view = m_frame->view();
    if (!root || !view)
        return LayoutRect();

    LayoutRect selectionRect = root->selectionBounds(clipToVisibleContent);
    return clipToVisibleContent ? intersection(selectionRect, view->visibleContentRect()) : selectionRect;
}

void FrameSelection::getClippedVisibleTextRectangles(Vector<FloatRect>& rectangles) const
{
    RenderView* root = m_frame->contentRenderer();
    if (!root)
        return;

    FloatRect visibleContentRect = m_frame->view()->visibleContentRect();

    Vector<FloatQuad> quads;
    toNormalizedRange()->textQuads(quads, true);

    size_t size = quads.size();
    for (size_t i = 0; i < size; ++i) {
        FloatRect intersectionRect = intersection(quads[i].enclosingBoundingBox(), visibleContentRect);
        if (!intersectionRect.isEmpty())
            rectangles.append(intersectionRect);
    }
}

// Scans logically forward from "start", including any child frames.
static HTMLFormElement* scanForForm(Node* start)
{
    for (Node* node = start; node; node = node->traverseNextNode()) {
        if (node->hasTagName(formTag))
            return static_cast<HTMLFormElement*>(node);
        if (node->isHTMLElement() && toHTMLElement(node)->isFormControlElement())
            return static_cast<HTMLFormControlElement*>(node)->form();
        if (node->hasTagName(frameTag) || node->hasTagName(iframeTag)) {
            Node* childDocument = static_cast<HTMLFrameElementBase*>(node)->contentDocument();
            if (HTMLFormElement* frameResult = scanForForm(childDocument))
                return frameResult;
        }
    }
    return 0;
}

// We look for either the form containing the current focus, or for one immediately after it
HTMLFormElement* FrameSelection::currentForm() const
{
    // Start looking either at the active (first responder) node, or where the selection is.
    Node* start = m_frame->document()->focusedNode();
    if (!start)
        start = this->start().deprecatedNode();

    // Try walking up the node tree to find a form element.
    Node* node;
    for (node = start; node; node = node->parentNode()) {
        if (node->hasTagName(formTag))
            return static_cast<HTMLFormElement*>(node);
        if (node->isHTMLElement() && toHTMLElement(node)->isFormControlElement())
            return static_cast<HTMLFormControlElement*>(node)->form();
    }

    // Try walking forward in the node tree to find a form element.
    return scanForForm(start);
}

void FrameSelection::revealSelection(const ScrollAlignment& alignment, bool revealExtent)
{
    LayoutRect rect;

    switch (selectionType()) {
    case VisibleSelection::NoSelection:
        return;
    case VisibleSelection::CaretSelection:
        rect = absoluteCaretBounds();
        break;
    case VisibleSelection::RangeSelection:
        rect = revealExtent ? VisiblePosition(extent()).absoluteCaretBounds() : enclosingIntRect(bounds(false));
        break;
    }

    Position start = this->start();
    ASSERT(start.deprecatedNode());
    if (start.deprecatedNode() && start.deprecatedNode()->renderer()) {
        // FIXME: This code only handles scrolling the startContainer's layer, but
        // the selection rect could intersect more than just that.
        // See <rdar://problem/4799899>.
        if (RenderLayer* layer = start.deprecatedNode()->renderer()->enclosingLayer()) {
            layer->scrollRectToVisible(rect, alignment, alignment);
            updateAppearance();
        }
    }
}

void FrameSelection::setSelectionFromNone()
{
    // Put a caret inside the body if the entire frame is editable (either the
    // entire WebView is editable or designMode is on for this document).

    Document* document = m_frame->document();
    bool caretBrowsing = m_frame->settings() && m_frame->settings()->caretBrowsingEnabled();
    if (!isNone() || !(document->rendererIsEditable() || caretBrowsing))
        return;

    Node* node = document->documentElement();
    while (node && !node->hasTagName(bodyTag))
        node = node->traverseNextNode();
    if (node)
        setSelection(VisibleSelection(firstPositionInOrBeforeNode(node), DOWNSTREAM));
}

bool FrameSelection::shouldChangeSelection(const VisibleSelection& newSelection) const
{
    return m_frame->editor()->shouldChangeSelection(selection(), newSelection, newSelection.affinity(), false);
}

#ifndef NDEBUG

void FrameSelection::formatForDebugger(char* buffer, unsigned length) const
{
    m_selection.formatForDebugger(buffer, length);
}

void FrameSelection::showTreeForThis() const
{
    m_selection.showTreeForThis();
}

#endif

}

#ifndef NDEBUG

void showTree(const WebCore::FrameSelection& sel)
{
    sel.showTreeForThis();
}

void showTree(const WebCore::FrameSelection* sel)
{
    if (sel)
        sel->showTreeForThis();
}

#endif
