Source/core/editing/htmlediting.cpp

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
isAtomicNode
comparePositions
comparePositions
comparePositions
highestEditableRoot
lowestEditableAncestor
isEditablePosition
isAtUnsplittableElement
isRichlyEditablePosition
editableRootForPosition
unsplittableElementForPosition
nextCandidate
nextVisuallyDistinctCandidate
previousCandidate
previousVisuallyDistinctCandidate
firstEditablePositionAfterPositionInRoot
lastEditablePositionBeforePositionInRoot
isBlock
isInline
enclosingBlock
directionOfEnclosingBlock
lastOffsetForEditing
stringWithRebalancedWhitespace
isTableStructureNode
nonBreakingSpaceString
isSpecialElement
firstInSpecialElement
lastInSpecialElement
positionBeforeContainingSpecialElement
positionAfterContainingSpecialElement
isFirstPositionAfterTable
isLastPositionBeforeTable
visiblePositionBeforeNode
visiblePositionAfterNode
createRange
isListElement
isListItem
enclosingNodeWithTag
enclosingNodeOfType
highestEnclosingNodeOfType
hasARenderedDescendant
highestNodeToRemoveInPruning
enclosingTableCell
enclosingAnchorElement
enclosingList
enclosingListChild
enclosingEmptyListItem
outermostEnclosingList
canMergeLists
isRenderedTableElement
isRenderedTable
isTableCell
isEmptyTableCell
createDefaultParagraphElement
createBreakElement
createOrderedListElement
createUnorderedListElement
createListItemElement
createHTMLElement
createHTMLElement
isTabSpanNode
isTabSpanTextNode
tabSpanNode
createTabSpanElement
createTabSpanElement
createTabSpanElement
isNodeRendered
numEnclosingMailBlockquotes
updatePositionForNodeRemoval
isMailBlockquote
caretMinOffset
caretMaxOffset
lineBreakExistsAtVisiblePosition
lineBreakExistsAtPosition
selectionForParagraphIteration
indexForVisiblePosition
visiblePositionForIndex
isVisiblyAdjacent
isNodeVisiblyContainedWithin
isRenderedAsNonInlineTableImageOrHR
areIdenticalElements
isNonTableCellHTMLBlockElement
adjustedSelectionStartForStyleComputation
/*
 * Copyright (C) 2004, 2005, 2006, 2007 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/htmlediting.h"

#include "HTMLElementFactory.h"
#include "HTMLNames.h"
#include "bindings/v8/ExceptionState.h"
#include "bindings/v8/ExceptionStatePlaceholder.h"
#include "core/dom/Document.h"
#include "core/dom/NodeTraversal.h"
#include "core/dom/PositionIterator.h"
#include "core/dom/Range.h"
#include "core/dom/Text.h"
#include "core/dom/shadow/ShadowRoot.h"
#include "core/editing/Editor.h"
#include "core/editing/HTMLInterchange.h"
#include "core/editing/PlainTextRange.h"
#include "core/editing/TextIterator.h"
#include "core/editing/VisiblePosition.h"
#include "core/editing/VisibleSelection.h"
#include "core/editing/VisibleUnits.h"
#include "core/frame/LocalFrame.h"
#include "core/html/HTMLBRElement.h"
#include "core/html/HTMLDivElement.h"
#include "core/html/HTMLLIElement.h"
#include "core/html/HTMLOListElement.h"
#include "core/html/HTMLParagraphElement.h"
#include "core/html/HTMLTableCellElement.h"
#include "core/html/HTMLUListElement.h"
#include "core/rendering/RenderObject.h"
#include "wtf/Assertions.h"
#include "wtf/StdLibExtras.h"
#include "wtf/text/StringBuilder.h"

using namespace std;

namespace WebCore {

using namespace HTMLNames;

// Atomic means that the node has no children, or has children which are ignored for the
// purposes of editing.
bool isAtomicNode(const Node *node)
{
    return node && (!node->hasChildren() || editingIgnoresContent(node));
}

// Compare two positions, taking into account the possibility that one or both
// could be inside a shadow tree. Only works for non-null values.
int comparePositions(const Position& a, const Position& b)
{
    ASSERT(a.isNotNull());
    ASSERT(b.isNotNull());
    TreeScope* commonScope = commonTreeScope(a.containerNode(), b.containerNode());

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

    Node* nodeA = commonScope->ancestorInThisScope(a.containerNode());
    ASSERT(nodeA);
    bool hasDescendentA = nodeA != a.containerNode();
    int offsetA = hasDescendentA ? 0 : a.computeOffsetInContainerNode();

    Node* nodeB = commonScope->ancestorInThisScope(b.containerNode());
    ASSERT(nodeB);
    bool hasDescendentB = nodeB != b.containerNode();
    int offsetB = hasDescendentB ? 0 : b.computeOffsetInContainerNode();

    int bias = 0;
    if (nodeA == nodeB) {
        if (hasDescendentA)
            bias = -1;
        else if (hasDescendentB)
            bias = 1;
    }

    int result = Range::compareBoundaryPoints(nodeA, offsetA, nodeB, offsetB, IGNORE_EXCEPTION);
    return result ? result : bias;
}

int comparePositions(const PositionWithAffinity& a, const PositionWithAffinity& b)
{
    return comparePositions(a.position(), b.position());
}

int comparePositions(const VisiblePosition& a, const VisiblePosition& b)
{
    return comparePositions(a.deepEquivalent(), b.deepEquivalent());
}

Node* highestEditableRoot(const Position& position, EditableType editableType)
{
    Node* node = position.deprecatedNode();
    if (!node)
        return 0;

    Node* highestRoot = editableRootForPosition(position, editableType);
    if (!highestRoot)
        return 0;

    if (isHTMLBodyElement(*highestRoot))
        return highestRoot;

    node = highestRoot->parentNode();
    while (node) {
        if (node->rendererIsEditable(editableType))
            highestRoot = node;
        if (isHTMLBodyElement(*node))
            break;
        node = node->parentNode();
    }

    return highestRoot;
}

Node* lowestEditableAncestor(Node* node)
{
    while (node) {
        if (node->rendererIsEditable())
            return node->rootEditableElement();
        if (isHTMLBodyElement(*node))
            break;
        node = node->parentNode();
    }

    return 0;
}

bool isEditablePosition(const Position& p, EditableType editableType, EUpdateStyle updateStyle)
{
    Node* node = p.deprecatedNode();
    if (!node)
        return false;
    if (updateStyle == UpdateStyle)
        node->document().updateLayoutIgnorePendingStylesheets();
    else
        ASSERT(updateStyle == DoNotUpdateStyle);

    if (isRenderedTableElement(node))
        node = node->parentNode();

    return node->rendererIsEditable(editableType);
}

bool isAtUnsplittableElement(const Position& pos)
{
    Node* node = pos.deprecatedNode();
    return (node == editableRootForPosition(pos) || node == enclosingNodeOfType(pos, &isTableCell));
}


bool isRichlyEditablePosition(const Position& p, EditableType editableType)
{
    Node* node = p.deprecatedNode();
    if (!node)
        return false;

    if (isRenderedTableElement(node))
        node = node->parentNode();

    return node->rendererIsRichlyEditable(editableType);
}

Element* editableRootForPosition(const Position& p, EditableType editableType)
{
    Node* node = p.containerNode();
    if (!node)
        return 0;

    if (isRenderedTableElement(node))
        node = node->parentNode();

    return node->rootEditableElement(editableType);
}

// Finds the enclosing element until which the tree can be split.
// When a user hits ENTER, he/she won't expect this element to be split into two.
// You may pass it as the second argument of splitTreeToNode.
Element* unsplittableElementForPosition(const Position& p)
{
    // Since enclosingNodeOfType won't search beyond the highest root editable node,
    // this code works even if the closest table cell was outside of the root editable node.
    Element* enclosingCell = toElement(enclosingNodeOfType(p, &isTableCell));
    if (enclosingCell)
        return enclosingCell;

    return editableRootForPosition(p);
}

Position nextCandidate(const Position& position)
{
    PositionIterator p = position;
    while (!p.atEnd()) {
        p.increment();
        if (p.isCandidate())
            return p;
    }
    return Position();
}

Position nextVisuallyDistinctCandidate(const Position& position)
{
    Position p = position;
    Position downstreamStart = p.downstream();
    while (!p.atEndOfTree()) {
        p = p.next(Character);
        if (p.isCandidate() && p.downstream() != downstreamStart)
            return p;
    }
    return Position();
}

Position previousCandidate(const Position& position)
{
    PositionIterator p = position;
    while (!p.atStart()) {
        p.decrement();
        if (p.isCandidate())
            return p;
    }
    return Position();
}

Position previousVisuallyDistinctCandidate(const Position& position)
{
    Position p = position;
    Position downstreamStart = p.downstream();
    while (!p.atStartOfTree()) {
        p = p.previous(Character);
        if (p.isCandidate() && p.downstream() != downstreamStart)
            return p;
    }
    return Position();
}

VisiblePosition firstEditablePositionAfterPositionInRoot(const Position& position, Node* highestRoot)
{
    // position falls before highestRoot.
    if (comparePositions(position, firstPositionInNode(highestRoot)) == -1 && highestRoot->rendererIsEditable())
        return VisiblePosition(firstPositionInNode(highestRoot));

    Position p = position;

    if (position.deprecatedNode()->treeScope() != highestRoot->treeScope()) {
        Node* shadowAncestor = highestRoot->treeScope().ancestorInThisScope(p.deprecatedNode());
        if (!shadowAncestor)
            return VisiblePosition();

        p = positionAfterNode(shadowAncestor);
    }

    while (p.deprecatedNode() && !isEditablePosition(p) && p.deprecatedNode()->isDescendantOf(highestRoot))
        p = isAtomicNode(p.deprecatedNode()) ? positionInParentAfterNode(*p.deprecatedNode()) : nextVisuallyDistinctCandidate(p);

    if (p.deprecatedNode() && p.deprecatedNode() != highestRoot && !p.deprecatedNode()->isDescendantOf(highestRoot))
        return VisiblePosition();

    return VisiblePosition(p);
}

VisiblePosition lastEditablePositionBeforePositionInRoot(const Position& position, Node* highestRoot)
{
    // When position falls after highestRoot, the result is easy to compute.
    if (comparePositions(position, lastPositionInNode(highestRoot)) == 1)
        return VisiblePosition(lastPositionInNode(highestRoot));

    Position p = position;

    if (position.deprecatedNode()->treeScope() != highestRoot->treeScope()) {
        Node* shadowAncestor = highestRoot->treeScope().ancestorInThisScope(p.deprecatedNode());
        if (!shadowAncestor)
            return VisiblePosition();

        p = firstPositionInOrBeforeNode(shadowAncestor);
    }

    while (p.deprecatedNode() && !isEditablePosition(p) && p.deprecatedNode()->isDescendantOf(highestRoot))
        p = isAtomicNode(p.deprecatedNode()) ? positionInParentBeforeNode(*p.deprecatedNode()) : previousVisuallyDistinctCandidate(p);

    if (p.deprecatedNode() && p.deprecatedNode() != highestRoot && !p.deprecatedNode()->isDescendantOf(highestRoot))
        return VisiblePosition();

    return VisiblePosition(p);
}

// FIXME: The method name, comment, and code say three different things here!
// Whether or not content before and after this node will collapse onto the same line as it.
bool isBlock(const Node* node)
{
    return node && node->renderer() && !node->renderer()->isInline() && !node->renderer()->isRubyText();
}

bool isInline(const Node* node)
{
    return node && node->renderer() && node->renderer()->isInline();
}

// FIXME: Deploy this in all of the places where enclosingBlockFlow/enclosingBlockFlowOrTableElement are used.
// FIXME: Pass a position to this function. The enclosing block of [table, x] for example, should be the
// block that contains the table and not the table, and this function should be the only one responsible for
// knowing about these kinds of special cases.
Element* enclosingBlock(Node* node, EditingBoundaryCrossingRule rule)
{
    Node* enclosingNode = enclosingNodeOfType(firstPositionInOrBeforeNode(node), isBlock, rule);
    return enclosingNode && enclosingNode->isElementNode() ? toElement(enclosingNode) : 0;
}

TextDirection directionOfEnclosingBlock(const Position& position)
{
    Node* enclosingBlockNode = enclosingBlock(position.containerNode());
    if (!enclosingBlockNode)
        return LTR;
    RenderObject* renderer = enclosingBlockNode->renderer();
    return renderer ? renderer->style()->direction() : LTR;
}

// This method is used to create positions in the DOM. It returns the maximum valid offset
// in a node. It returns 1 for some elements even though they do not have children, which
// creates technically invalid DOM Positions. Be sure to call parentAnchoredEquivalent
// on a Position before using it to create a DOM Range, or an exception will be thrown.
int lastOffsetForEditing(const Node* node)
{
    ASSERT(node);
    if (!node)
        return 0;
    if (node->offsetInCharacters())
        return node->maxCharacterOffset();

    if (node->hasChildren())
        return node->countChildren();

    // NOTE: This should preempt the childNodeCount for, e.g., select nodes
    if (editingIgnoresContent(node))
        return 1;

    return 0;
}

String stringWithRebalancedWhitespace(const String& string, bool startIsStartOfParagraph, bool endIsEndOfParagraph)
{
    unsigned length = string.length();

    StringBuilder rebalancedString;
    rebalancedString.reserveCapacity(length);

    bool previousCharacterWasSpace = false;
    for (size_t i = 0; i < length; i++) {
        UChar c = string[i];
        if (!isWhitespace(c)) {
            rebalancedString.append(c);
            previousCharacterWasSpace = false;
            continue;
        }

        if (previousCharacterWasSpace || (!i && startIsStartOfParagraph) || (i + 1 == length && endIsEndOfParagraph)) {
            rebalancedString.append(noBreakSpace);
            previousCharacterWasSpace = false;
        } else {
            rebalancedString.append(' ');
            previousCharacterWasSpace = true;
        }
    }

    ASSERT(rebalancedString.length() == length);

    return rebalancedString.toString();
}

bool isTableStructureNode(const Node *node)
{
    RenderObject* renderer = node->renderer();
    return (renderer && (renderer->isTableCell() || renderer->isTableRow() || renderer->isTableSection() || renderer->isRenderTableCol()));
}

const String& nonBreakingSpaceString()
{
    DEFINE_STATIC_LOCAL(String, nonBreakingSpaceString, (&noBreakSpace, 1));
    return nonBreakingSpaceString;
}

// FIXME: need to dump this
bool isSpecialElement(const Node *n)
{
    if (!n)
        return false;

    if (!n->isHTMLElement())
        return false;

    if (n->isLink())
        return true;

    RenderObject* renderer = n->renderer();
    if (!renderer)
        return false;

    if (renderer->style()->display() == TABLE || renderer->style()->display() == INLINE_TABLE)
        return true;

    if (renderer->style()->isFloating())
        return true;

    return false;
}

static Node* firstInSpecialElement(const Position& pos)
{
    Node* rootEditableElement = pos.containerNode()->rootEditableElement();
    for (Node* n = pos.deprecatedNode(); n && n->rootEditableElement() == rootEditableElement; n = n->parentNode())
        if (isSpecialElement(n)) {
            VisiblePosition vPos = VisiblePosition(pos, DOWNSTREAM);
            VisiblePosition firstInElement = VisiblePosition(firstPositionInOrBeforeNode(n), DOWNSTREAM);
            if (isRenderedTable(n) && vPos == firstInElement.next())
                return n;
            if (vPos == firstInElement)
                return n;
        }
    return 0;
}

static Node* lastInSpecialElement(const Position& pos)
{
    Node* rootEditableElement = pos.containerNode()->rootEditableElement();
    for (Node* n = pos.deprecatedNode(); n && n->rootEditableElement() == rootEditableElement; n = n->parentNode())
        if (isSpecialElement(n)) {
            VisiblePosition vPos = VisiblePosition(pos, DOWNSTREAM);
            VisiblePosition lastInElement = VisiblePosition(lastPositionInOrAfterNode(n), DOWNSTREAM);
            if (isRenderedTable(n) && vPos == lastInElement.previous())
                return n;
            if (vPos == lastInElement)
                return n;
        }
    return 0;
}

Position positionBeforeContainingSpecialElement(const Position& pos, Node** containingSpecialElement)
{
    Node* n = firstInSpecialElement(pos);
    if (!n)
        return pos;
    Position result = positionInParentBeforeNode(*n);
    if (result.isNull() || result.deprecatedNode()->rootEditableElement() != pos.deprecatedNode()->rootEditableElement())
        return pos;
    if (containingSpecialElement)
        *containingSpecialElement = n;
    return result;
}

Position positionAfterContainingSpecialElement(const Position& pos, Node **containingSpecialElement)
{
    Node* n = lastInSpecialElement(pos);
    if (!n)
        return pos;
    Position result = positionInParentAfterNode(*n);
    if (result.isNull() || result.deprecatedNode()->rootEditableElement() != pos.deprecatedNode()->rootEditableElement())
        return pos;
    if (containingSpecialElement)
        *containingSpecialElement = n;
    return result;
}

Node* isFirstPositionAfterTable(const VisiblePosition& visiblePosition)
{
    Position upstream(visiblePosition.deepEquivalent().upstream());
    if (isRenderedTable(upstream.deprecatedNode()) && upstream.atLastEditingPositionForNode())
        return upstream.deprecatedNode();

    return 0;
}

Node* isLastPositionBeforeTable(const VisiblePosition& visiblePosition)
{
    Position downstream(visiblePosition.deepEquivalent().downstream());
    if (isRenderedTable(downstream.deprecatedNode()) && downstream.atFirstEditingPositionForNode())
        return downstream.deprecatedNode();

    return 0;
}

// Returns the visible position at the beginning of a node
VisiblePosition visiblePositionBeforeNode(Node& node)
{
    if (node.hasChildren())
        return VisiblePosition(firstPositionInOrBeforeNode(&node), DOWNSTREAM);
    ASSERT(node.parentNode());
    ASSERT(!node.parentNode()->isShadowRoot());
    return VisiblePosition(positionInParentBeforeNode(node));
}

// Returns the visible position at the ending of a node
VisiblePosition visiblePositionAfterNode(Node& node)
{
    if (node.hasChildren())
        return VisiblePosition(lastPositionInOrAfterNode(&node), DOWNSTREAM);
    ASSERT(node.parentNode());
    ASSERT(!node.parentNode()->isShadowRoot());
    return VisiblePosition(positionInParentAfterNode(node));
}

// Create a range object with two visible positions, start and end.
// create(Document*, const Position&, const Position&); will use deprecatedEditingOffset
// Use this function instead of create a regular range object (avoiding editing offset).
PassRefPtrWillBeRawPtr<Range> createRange(Document& document, const VisiblePosition& start, const VisiblePosition& end, ExceptionState& exceptionState)
{
    RefPtrWillBeRawPtr<Range> selectedRange = Range::create(document);
    selectedRange->setStart(start.deepEquivalent().containerNode(), start.deepEquivalent().computeOffsetInContainerNode(), exceptionState);
    if (!exceptionState.hadException())
        selectedRange->setEnd(end.deepEquivalent().containerNode(), end.deepEquivalent().computeOffsetInContainerNode(), exceptionState);
    return selectedRange.release();
}

bool isListElement(Node* n)
{
    return (n && (isHTMLUListElement(*n) || isHTMLOListElement(*n) || isHTMLDListElement(*n)));
}

bool isListItem(const Node* n)
{
    return n && n->renderer() && n->renderer()->isListItem();
}

Node* enclosingNodeWithTag(const Position& p, const QualifiedName& tagName)
{
    if (p.isNull())
        return 0;

    Node* root = highestEditableRoot(p);
    for (Node* n = p.deprecatedNode(); n; n = n->parentNode()) {
        if (root && !n->rendererIsEditable())
            continue;
        if (n->hasTagName(tagName))
            return n;
        if (n == root)
            return 0;
    }

    return 0;
}

Node* enclosingNodeOfType(const Position& p, bool (*nodeIsOfType)(const Node*), EditingBoundaryCrossingRule rule)
{
    // FIXME: support CanSkipCrossEditingBoundary
    ASSERT(rule == CanCrossEditingBoundary || rule == CannotCrossEditingBoundary);
    if (p.isNull())
        return 0;

    Node* root = rule == CannotCrossEditingBoundary ? highestEditableRoot(p) : 0;
    for (Node* n = p.deprecatedNode(); n; n = n->parentNode()) {
        // Don't return a non-editable node if the input position was editable, since
        // the callers from editing will no doubt want to perform editing inside the returned node.
        if (root && !n->rendererIsEditable())
            continue;
        if (nodeIsOfType(n))
            return n;
        if (n == root)
            return 0;
    }

    return 0;
}

Node* highestEnclosingNodeOfType(const Position& p, bool (*nodeIsOfType)(const Node*), EditingBoundaryCrossingRule rule, Node* stayWithin)
{
    Node* highest = 0;
    Node* root = rule == CannotCrossEditingBoundary ? highestEditableRoot(p) : 0;
    for (Node* n = p.containerNode(); n && n != stayWithin; n = n->parentNode()) {
        if (root && !n->rendererIsEditable())
            continue;
        if (nodeIsOfType(n))
            highest = n;
        if (n == root)
            break;
    }

    return highest;
}

static bool hasARenderedDescendant(Node* node, Node* excludedNode)
{
    for (Node* n = node->firstChild(); n;) {
        if (n == excludedNode) {
            n = NodeTraversal::nextSkippingChildren(*n, node);
            continue;
        }
        if (n->renderer())
            return true;
        n = NodeTraversal::next(*n, node);
    }
    return false;
}

Node* highestNodeToRemoveInPruning(Node* node, Node* excludeNode)
{
    Node* previousNode = 0;
    Node* rootEditableElement = node ? node->rootEditableElement() : 0;
    for (; node; node = node->parentNode()) {
        if (RenderObject* renderer = node->renderer()) {
            if (!renderer->canHaveChildren() || hasARenderedDescendant(node, previousNode) || rootEditableElement == node || excludeNode == node)
                return previousNode;
        }
        previousNode = node;
    }
    return 0;
}

Node* enclosingTableCell(const Position& p)
{
    return toElement(enclosingNodeOfType(p, isTableCell));
}

Element* enclosingAnchorElement(const Position& p)
{
    if (p.isNull())
        return 0;

    Node* node = p.deprecatedNode();
    while (node && !(node->isElementNode() && node->isLink()))
        node = node->parentNode();
    return toElement(node);
}

HTMLElement* enclosingList(Node* node)
{
    if (!node)
        return 0;

    Node* root = highestEditableRoot(firstPositionInOrBeforeNode(node));

    for (ContainerNode* n = node->parentNode(); n; n = n->parentNode()) {
        if (isHTMLUListElement(*n) || isHTMLOListElement(*n))
            return toHTMLElement(n);
        if (n == root)
            return 0;
    }

    return 0;
}

Node* enclosingListChild(Node *node)
{
    if (!node)
        return 0;
    // Check for a list item element, or for a node whose parent is a list element. Such a node
    // will appear visually as a list item (but without a list marker)
    Node* root = highestEditableRoot(firstPositionInOrBeforeNode(node));

    // FIXME: This function is inappropriately named if it starts with node instead of node->parentNode()
    for (Node* n = node; n && n->parentNode(); n = n->parentNode()) {
        if (isHTMLLIElement(*n) || (isListElement(n->parentNode()) && n != root))
            return n;
        if (n == root || isTableCell(n))
            return 0;
    }

    return 0;
}

// FIXME: This method should not need to call isStartOfParagraph/isEndOfParagraph
Node* enclosingEmptyListItem(const VisiblePosition& visiblePos)
{
    // Check that position is on a line by itself inside a list item
    Node* listChildNode = enclosingListChild(visiblePos.deepEquivalent().deprecatedNode());
    if (!listChildNode || !isStartOfParagraph(visiblePos) || !isEndOfParagraph(visiblePos))
        return 0;

    VisiblePosition firstInListChild(firstPositionInOrBeforeNode(listChildNode));
    VisiblePosition lastInListChild(lastPositionInOrAfterNode(listChildNode));

    if (firstInListChild != visiblePos || lastInListChild != visiblePos)
        return 0;

    return listChildNode;
}

HTMLElement* outermostEnclosingList(Node* node, Node* rootList)
{
    HTMLElement* list = enclosingList(node);
    if (!list)
        return 0;

    while (HTMLElement* nextList = enclosingList(list)) {
        if (nextList == rootList)
            break;
        list = nextList;
    }

    return list;
}

bool canMergeLists(Element* firstList, Element* secondList)
{
    if (!firstList || !secondList || !firstList->isHTMLElement() || !secondList->isHTMLElement())
        return false;

    return firstList->hasTagName(secondList->tagQName()) // make sure the list types match (ol vs. ul)
    && firstList->rendererIsEditable() && secondList->rendererIsEditable() // both lists are editable
    && firstList->rootEditableElement() == secondList->rootEditableElement() // don't cross editing boundaries
    && isVisiblyAdjacent(positionInParentAfterNode(*firstList), positionInParentBeforeNode(*secondList));
    // Make sure there is no visible content between this li and the previous list
}

bool isRenderedTableElement(const Node* node)
{
    return isHTMLTableElement(*node) && node->renderer();
}

bool isRenderedTable(const Node* node)
{
    if (!node || !node->isElementNode())
        return false;

    RenderObject* renderer = node->renderer();
    return (renderer && renderer->isTable());
}

bool isTableCell(const Node* node)
{
    ASSERT(node);
    RenderObject* r = node->renderer();
    return r ? r->isTableCell() : isHTMLTableCellElement(*node);
}

bool isEmptyTableCell(const Node* node)
{
    // Returns true IFF the passed in node is one of:
    //   .) a table cell with no children,
    //   .) a table cell with a single BR child, and which has no other child renderers, including :before and :after renderers
    //   .) the BR child of such a table cell

    // Find rendered node
    while (node && !node->renderer())
        node = node->parentNode();
    if (!node)
        return false;

    // Make sure the rendered node is a table cell or <br>.
    // If it's a <br>, then the parent node has to be a table cell.
    RenderObject* renderer = node->renderer();
    if (renderer->isBR()) {
        renderer = renderer->parent();
        if (!renderer)
            return false;
    }
    if (!renderer->isTableCell())
        return false;

    // Check that the table cell contains no child renderers except for perhaps a single <br>.
    RenderObject* childRenderer = renderer->firstChild();
    if (!childRenderer)
        return true;
    if (!childRenderer->isBR())
        return false;
    return !childRenderer->nextSibling();
}

PassRefPtr<HTMLElement> createDefaultParagraphElement(Document& document)
{
    switch (document.frame()->editor().defaultParagraphSeparator()) {
    case EditorParagraphSeparatorIsDiv:
        return HTMLDivElement::create(document);
    case EditorParagraphSeparatorIsP:
        return HTMLParagraphElement::create(document);
    }

    ASSERT_NOT_REACHED();
    return nullptr;
}

PassRefPtr<HTMLElement> createBreakElement(Document& document)
{
    return HTMLBRElement::create(document);
}

PassRefPtr<HTMLElement> createOrderedListElement(Document& document)
{
    return HTMLOListElement::create(document);
}

PassRefPtr<HTMLElement> createUnorderedListElement(Document& document)
{
    return HTMLUListElement::create(document);
}

PassRefPtr<HTMLElement> createListItemElement(Document& document)
{
    return HTMLLIElement::create(document);
}

PassRefPtr<HTMLElement> createHTMLElement(Document& document, const QualifiedName& name)
{
    return createHTMLElement(document, name.localName());
}

PassRefPtr<HTMLElement> createHTMLElement(Document& document, const AtomicString& tagName)
{
    return HTMLElementFactory::createHTMLElement(tagName, document, 0, false);
}

bool isTabSpanNode(const Node* node)
{
    return isHTMLSpanElement(node) && toElement(node)->getAttribute(classAttr) == AppleTabSpanClass;
}

bool isTabSpanTextNode(const Node* node)
{
    return node && node->isTextNode() && node->parentNode() && isTabSpanNode(node->parentNode());
}

Node* tabSpanNode(const Node* node)
{
    return isTabSpanTextNode(node) ? node->parentNode() : 0;
}

PassRefPtr<Element> createTabSpanElement(Document& document, PassRefPtr<Node> prpTabTextNode)
{
    RefPtr<Node> tabTextNode = prpTabTextNode;

    // Make the span to hold the tab.
    RefPtr<Element> spanElement = document.createElement(spanTag, false);
    spanElement->setAttribute(classAttr, AppleTabSpanClass);
    spanElement->setAttribute(styleAttr, "white-space:pre");

    // Add tab text to that span.
    if (!tabTextNode)
        tabTextNode = document.createEditingTextNode("\t");

    spanElement->appendChild(tabTextNode.release());

    return spanElement.release();
}

PassRefPtr<Element> createTabSpanElement(Document& document, const String& tabText)
{
    return createTabSpanElement(document, document.createTextNode(tabText));
}

PassRefPtr<Element> createTabSpanElement(Document& document)
{
    return createTabSpanElement(document, PassRefPtr<Node>());
}

bool isNodeRendered(const Node *node)
{
    if (!node)
        return false;

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

    return renderer->style()->visibility() == VISIBLE;
}

unsigned numEnclosingMailBlockquotes(const Position& p)
{
    unsigned num = 0;
    for (Node* n = p.deprecatedNode(); n; n = n->parentNode())
        if (isMailBlockquote(n))
            num++;

    return num;
}

void updatePositionForNodeRemoval(Position& position, Node& node)
{
    if (position.isNull())
        return;
    switch (position.anchorType()) {
    case Position::PositionIsBeforeChildren:
        if (position.containerNode() == node)
            position = positionInParentBeforeNode(node);
        break;
    case Position::PositionIsAfterChildren:
        if (position.containerNode() == node)
            position = positionInParentAfterNode(node);
        break;
    case Position::PositionIsOffsetInAnchor:
        if (position.containerNode() == node.parentNode() && static_cast<unsigned>(position.offsetInContainerNode()) > node.nodeIndex())
            position.moveToOffset(position.offsetInContainerNode() - 1);
        else if (node.containsIncludingShadowDOM(position.containerNode()))
            position = positionInParentBeforeNode(node);
        break;
    case Position::PositionIsAfterAnchor:
        if (node.containsIncludingShadowDOM(position.anchorNode()))
            position = positionInParentAfterNode(node);
        break;
    case Position::PositionIsBeforeAnchor:
        if (node.containsIncludingShadowDOM(position.anchorNode()))
            position = positionInParentBeforeNode(node);
        break;
    }
}

bool isMailBlockquote(const Node *node)
{
    if (!node || !node->hasTagName(blockquoteTag))
        return false;

    return toElement(node)->getAttribute("type") == "cite";
}

int caretMinOffset(const Node* n)
{
    RenderObject* r = n->renderer();
    ASSERT(!n->isCharacterDataNode() || !r || r->isText()); // FIXME: This was a runtime check that seemingly couldn't fail; changed it to an assertion for now.
    return r ? r->caretMinOffset() : 0;
}

// If a node can contain candidates for VisiblePositions, return the offset of the last candidate, otherwise
// return the number of children for container nodes and the length for unrendered text nodes.
int caretMaxOffset(const Node* n)
{
    // For rendered text nodes, return the last position that a caret could occupy.
    if (n->isTextNode() && n->renderer())
        return n->renderer()->caretMaxOffset();
    // For containers return the number of children. For others do the same as above.
    return lastOffsetForEditing(n);
}

bool lineBreakExistsAtVisiblePosition(const VisiblePosition& visiblePosition)
{
    return lineBreakExistsAtPosition(visiblePosition.deepEquivalent().downstream());
}

bool lineBreakExistsAtPosition(const Position& position)
{
    if (position.isNull())
        return false;

    if (isHTMLBRElement(*position.anchorNode()) && position.atFirstEditingPositionForNode())
        return true;

    if (!position.anchorNode()->renderer())
        return false;

    if (!position.anchorNode()->isTextNode() || !position.anchorNode()->renderer()->style()->preserveNewline())
        return false;

    Text* textNode = toText(position.anchorNode());
    unsigned offset = position.offsetInContainerNode();
    return offset < textNode->length() && textNode->data()[offset] == '\n';
}

// Modifies selections that have an end point at the edge of a table
// that contains the other endpoint so that they don't confuse
// code that iterates over selected paragraphs.
VisibleSelection selectionForParagraphIteration(const VisibleSelection& original)
{
    VisibleSelection newSelection(original);
    VisiblePosition startOfSelection(newSelection.visibleStart());
    VisiblePosition endOfSelection(newSelection.visibleEnd());

    // If the end of the selection to modify is just after a table, and
    // if the start of the selection is inside that table, then the last paragraph
    // that we'll want modify is the last one inside the table, not the table itself
    // (a table is itself a paragraph).
    if (Node* table = isFirstPositionAfterTable(endOfSelection))
        if (startOfSelection.deepEquivalent().deprecatedNode()->isDescendantOf(table))
            newSelection = VisibleSelection(startOfSelection, endOfSelection.previous(CannotCrossEditingBoundary));

    // If the start of the selection to modify is just before a table,
    // and if the end of the selection is inside that table, then the first paragraph
    // we'll want to modify is the first one inside the table, not the paragraph
    // containing the table itself.
    if (Node* table = isLastPositionBeforeTable(startOfSelection))
        if (endOfSelection.deepEquivalent().deprecatedNode()->isDescendantOf(table))
            newSelection = VisibleSelection(startOfSelection.next(CannotCrossEditingBoundary), endOfSelection);

    return newSelection;
}

// FIXME: indexForVisiblePosition and visiblePositionForIndex use TextIterators to convert between
// VisiblePositions and indices. But TextIterator iteration using TextIteratorEmitsCharactersBetweenAllVisiblePositions
// does not exactly match VisiblePosition iteration, so using them to preserve a selection during an editing
// opertion is unreliable. TextIterator's TextIteratorEmitsCharactersBetweenAllVisiblePositions mode needs to be fixed,
// or these functions need to be changed to iterate using actual VisiblePositions.
// FIXME: Deploy these functions everywhere that TextIterators are used to convert between VisiblePositions and indices.
int indexForVisiblePosition(const VisiblePosition& visiblePosition, RefPtr<ContainerNode>& scope)
{
    if (visiblePosition.isNull())
        return 0;

    Position p(visiblePosition.deepEquivalent());
    Document& document = *p.document();
    ShadowRoot* shadowRoot = p.anchorNode()->containingShadowRoot();

    if (shadowRoot)
        scope = shadowRoot;
    else
        scope = document.documentElement();

    RefPtrWillBeRawPtr<Range> range = Range::create(document, firstPositionInNode(scope.get()), p.parentAnchoredEquivalent());

    return TextIterator::rangeLength(range.get(), true);
}

VisiblePosition visiblePositionForIndex(int index, ContainerNode* scope)
{
    if (!scope)
        return VisiblePosition();
    RefPtrWillBeRawPtr<Range> range = PlainTextRange(index).createRangeForSelection(*scope);
    // Check for an invalid index. Certain editing operations invalidate indices because
    // of problems with TextIteratorEmitsCharactersBetweenAllVisiblePositions.
    if (!range)
        return VisiblePosition();
    return VisiblePosition(range->startPosition());
}

// Determines whether two positions are visibly next to each other (first then second)
// while ignoring whitespaces and unrendered nodes
bool isVisiblyAdjacent(const Position& first, const Position& second)
{
    return VisiblePosition(first) == VisiblePosition(second.upstream());
}

// Determines whether a node is inside a range or visibly starts and ends at the boundaries of the range.
// Call this function to determine whether a node is visibly fit inside selectedRange
bool isNodeVisiblyContainedWithin(Node& node, const Range& selectedRange)
{
    // If the node is inside the range, then it surely is contained within
    if (selectedRange.compareNode(&node, IGNORE_EXCEPTION) == Range::NODE_INSIDE)
        return true;

    bool startIsVisuallySame = visiblePositionBeforeNode(node) == VisiblePosition(selectedRange.startPosition());
    if (startIsVisuallySame && comparePositions(positionInParentAfterNode(node), selectedRange.endPosition()) < 0)
        return true;

    bool endIsVisuallySame = visiblePositionAfterNode(node) == VisiblePosition(selectedRange.endPosition());
    if (endIsVisuallySame && comparePositions(selectedRange.startPosition(), positionInParentBeforeNode(node)) < 0)
        return true;

    return startIsVisuallySame && endIsVisuallySame;
}

bool isRenderedAsNonInlineTableImageOrHR(const Node* node)
{
    if (!node)
        return false;
    RenderObject* renderer = node->renderer();
    return renderer && ((renderer->isTable() && !renderer->isInline()) || (renderer->isImage() && !renderer->isInline()) || renderer->isHR());
}

bool areIdenticalElements(const Node* first, const Node* second)
{
    if (!first->isElementNode() || !second->isElementNode())
        return false;

    const Element* firstElement = toElement(first);
    const Element* secondElement = toElement(second);
    if (!firstElement->hasTagName(secondElement->tagQName()))
        return false;

    return firstElement->hasEquivalentAttributes(secondElement);
}

bool isNonTableCellHTMLBlockElement(const Node* node)
{
    return node->hasTagName(listingTag)
        || node->hasTagName(olTag)
        || node->hasTagName(preTag)
        || node->hasTagName(tableTag)
        || node->hasTagName(ulTag)
        || node->hasTagName(xmpTag)
        || node->hasTagName(h1Tag)
        || node->hasTagName(h2Tag)
        || node->hasTagName(h3Tag)
        || node->hasTagName(h4Tag)
        || node->hasTagName(h5Tag);
}

Position adjustedSelectionStartForStyleComputation(const VisibleSelection& selection)
{
    // This function is used by range style computations to avoid bugs like:
    // <rdar://problem/4017641> REGRESSION (Mail): you can only bold/unbold a selection starting from end of line once
    // It is important to skip certain irrelevant content at the start of the selection, so we do not wind up
    // with a spurious "mixed" style.

    VisiblePosition visiblePosition(selection.start());
    if (visiblePosition.isNull())
        return Position();

    // if the selection is a caret, just return the position, since the style
    // behind us is relevant
    if (selection.isCaret())
        return visiblePosition.deepEquivalent();

    // if the selection starts just before a paragraph break, skip over it
    if (isEndOfParagraph(visiblePosition))
        return visiblePosition.next().deepEquivalent().downstream();

    // otherwise, make sure to be at the start of the first selected node,
    // instead of possibly at the end of the last node before the selection
    return visiblePosition.deepEquivalent().downstream();
}

} // namespace WebCore
/* [<][>][^][v][top][bottom][index][help] */
root/Source/core/editing/htmlediting.cpp

DEFINITIONS
