flutter_flutter/engine/core/editing/htmlediting.h

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 * Copyright (C) 2004, 2006, 2008 Apple Inc. All rights reserved.
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#ifndef SKY_ENGINE_CORE_EDITING_HTMLEDITING_H_
#define SKY_ENGINE_CORE_EDITING_HTMLEDITING_H_

#include "sky/engine/core/dom/Position.h"
#include "sky/engine/core/editing/EditingBoundary.h"
#include "sky/engine/platform/text/TextDirection.h"
#include "sky/engine/wtf/Forward.h"
#include "sky/engine/wtf/unicode/CharacterNames.h"

namespace blink {

class Document;
class Element;
class ExceptionState;
class HTMLElement;
class Node;
class Position;
class PositionWithAffinity;
class Range;
class VisiblePosition;
class VisibleSelection;


// This file contains a set of helper functions used by the editing commands

// -------------------------------------------------------------------------
// Node
// -------------------------------------------------------------------------

// Functions returning Node

ContainerNode* highestEditableRoot(const Position&, EditableType = ContentIsEditable);

Node* highestEnclosingNodeOfType(const Position&, bool (*nodeIsOfType)(const Node*),
    EditingBoundaryCrossingRule = CannotCrossEditingBoundary, Node* stayWithin = 0);
Node* highestNodeToRemoveInPruning(Node*, Node* excludeNode = 0);
Element* lowestEditableAncestor(Node*);

Element* enclosingBlock(Node*, EditingBoundaryCrossingRule = CannotCrossEditingBoundary);
Element* enclosingBlockFlowElement(Node&); // Deprecated, use enclosingBlock instead.
bool inSameContainingBlockFlowElement(Node*, Node*);
Element* enclosingAnchorElement(const Position&);
Element* enclosingElementWithTag(const Position&, const QualifiedName&);
Node* enclosingNodeOfType(const Position&, bool (*nodeIsOfType)(const Node*), EditingBoundaryCrossingRule = CannotCrossEditingBoundary);

Element* isLastPositionBeforeTable(const VisiblePosition&);
Element* isFirstPositionAfterTable(const VisiblePosition&);

// offset functions on Node

int lastOffsetForEditing(const Node*);
int caretMinOffset(const Node*);
int caretMaxOffset(const Node*);

// boolean functions on Node

// FIXME: editingIgnoresContent, canHaveChildrenForEditing, and isAtomicNode
// should be renamed to reflect its usage.

// Returns true for nodes that either have no content, or have content that is ignored (skipped over) while editing.
// There are no VisiblePositions inside these nodes.
inline bool editingIgnoresContent(const Node* node)
{
    return !node->canContainRangeEndPoint();
}

inline bool canHaveChildrenForEditing(const Node* node)
{
    return !node->isTextNode() && node->canContainRangeEndPoint();
}

bool isAtomicNode(const Node*);
bool isBlock(const Node*);
bool isInline(const Node*);
bool isSpecialHTMLElement(const Node*);
bool isMailHTMLBlockquoteElement(const Node*);
bool isRenderedTableElement(const Node*);
bool isEmptyTableCell(const Node*);
bool isNodeRendered(const Node*);
bool isNodeVisiblyContainedWithin(Node&, const Range&);
bool isRenderedAsNonInlineTableImageOrHR(const Node*);
bool areIdenticalElements(const Node*, const Node*);
bool isBlockFlowElement(const Node&);
TextDirection directionOfEnclosingBlock(const Position&);

// -------------------------------------------------------------------------
// Position
// -------------------------------------------------------------------------

// Functions returning Position

Position nextCandidate(const Position&);
Position previousCandidate(const Position&);

Position nextVisuallyDistinctCandidate(const Position&);
Position previousVisuallyDistinctCandidate(const Position&);

Position positionBeforeContainingSpecialElement(const Position&, HTMLElement** containingSpecialElement = 0);
Position positionAfterContainingSpecialElement(const Position&, HTMLElement** containingSpecialElement = 0);

inline Position firstPositionInOrBeforeNode(Node* node)
{
    if (!node)
        return Position();
    return editingIgnoresContent(node) ? positionBeforeNode(node) : firstPositionInNode(node);
}

inline Position lastPositionInOrAfterNode(Node* node)
{
    if (!node)
        return Position();
    return editingIgnoresContent(node) ? positionAfterNode(node) : lastPositionInNode(node);
}

Position lastEditablePositionBeforePositionInRoot(const Position&, Node*);

// comparision functions on Position

int comparePositions(const Position&, const Position&);
int comparePositions(const PositionWithAffinity&, const PositionWithAffinity&);

// boolean functions on Position

enum EUpdateStyle { UpdateStyle, DoNotUpdateStyle };
// FIXME: Both isEditablePosition and isRichlyEditablePosition rely on up-to-date
// style to give proper results. They shouldn't update style by default, but
// should make it clear that that is the contract.
// FIXME: isRichlyEditablePosition should also take EUpdateStyle.
bool isEditablePosition(const Position&, EditableType = ContentIsEditable, EUpdateStyle = UpdateStyle);
bool isRichlyEditablePosition(const Position&, EditableType = ContentIsEditable);
bool lineBreakExistsAtPosition(const Position&);
bool isVisiblyAdjacent(const Position& first, const Position& second);
bool isAtUnsplittableElement(const Position&);

// miscellaneous functions on Position

enum WhitespacePositionOption { NotConsiderNonCollapsibleWhitespace, ConsiderNonCollapsibleWhitespace };
Position leadingWhitespacePosition(const Position&, EAffinity, WhitespacePositionOption = NotConsiderNonCollapsibleWhitespace);
Position trailingWhitespacePosition(const Position&, EAffinity, WhitespacePositionOption = NotConsiderNonCollapsibleWhitespace);
unsigned numEnclosingMailBlockquotes(const Position&);
void updatePositionForNodeRemoval(Position&, Node&);

// -------------------------------------------------------------------------
// VisiblePosition
// -------------------------------------------------------------------------

// Functions returning VisiblePosition

VisiblePosition firstEditableVisiblePositionAfterPositionInRoot(const Position&, ContainerNode*);
VisiblePosition lastEditableVisiblePositionBeforePositionInRoot(const Position&, ContainerNode*);
VisiblePosition visiblePositionBeforeNode(Node&);
VisiblePosition visiblePositionAfterNode(Node&);

bool lineBreakExistsAtVisiblePosition(const VisiblePosition&);

int comparePositions(const VisiblePosition&, const VisiblePosition&);

int indexForVisiblePosition(const VisiblePosition&, RefPtr<ContainerNode>& scope);
VisiblePosition visiblePositionForIndex(int index, ContainerNode* scope);

// -------------------------------------------------------------------------
// Range
// -------------------------------------------------------------------------

// Functions returning Range

PassRefPtr<Range> createRange(Document&, const VisiblePosition& start, const VisiblePosition& end, ExceptionState&);

// -------------------------------------------------------------------------
// HTMLElement
// -------------------------------------------------------------------------

// Functions returning HTMLElement

PassRefPtr<HTMLElement> createDefaultParagraphElement(Document&);

// -------------------------------------------------------------------------
// Element
// -------------------------------------------------------------------------

Element* editableRootForPosition(const Position&, EditableType = ContentIsEditable);
Element* unsplittableElementForPosition(const Position&);

// Boolean functions on Element

bool canMergeLists(Element* firstList, Element* secondList);

// -------------------------------------------------------------------------
// VisibleSelection
// -------------------------------------------------------------------------

// Functions returning VisibleSelection
VisibleSelection selectionForParagraphIteration(const VisibleSelection&);

Position adjustedSelectionStartForStyleComputation(const VisibleSelection&);


// Miscellaneous functions on Text
inline bool isWhitespace(UChar c)
{
    return c == noBreakSpace || c == ' ' || c == '\n' || c == '\t';
}

// FIXME: Can't really answer this question correctly without knowing the white-space mode.
inline bool isCollapsibleWhitespace(UChar c)
{
    return c == ' ' || c == '\n';
}

inline bool isAmbiguousBoundaryCharacter(UChar character)
{
    // These are characters that can behave as word boundaries, but can appear within words.
    // If they are just typed, i.e. if they are immediately followed by a caret, we want to delay text checking until the next character has been typed.
    // FIXME: this is required until 6853027 is fixed and text checking can do this for us.
    return character == '\'' || character == rightSingleQuotationMark || character == hebrewPunctuationGershayim;
}

String stringWithRebalancedWhitespace(const String&, bool startIsStartOfParagraph, bool endIsEndOfParagraph);
const String& nonBreakingSpaceString();

}

#endif  // SKY_ENGINE_CORE_EDITING_HTMLEDITING_H_