C++ VisiblePosition::isNotNull方法代码示例

// FIXME: We should merge this function with ApplyBlockElementCommand::formatSelection
void IndentOutdentCommand::outdentRegion(const VisiblePosition& startOfSelection, const VisiblePosition& endOfSelection)
{
    VisiblePosition endOfLastParagraph = endOfParagraph(endOfSelection);

    if (endOfParagraph(startOfSelection) == endOfLastParagraph) {
        outdentParagraph();
        return;
    }
    
    Position originalSelectionEnd = endingSelection().end();
    VisiblePosition endOfCurrentParagraph = endOfParagraph(startOfSelection);
    VisiblePosition endAfterSelection = endOfParagraph(endOfParagraph(endOfSelection).next());

    while (endOfCurrentParagraph != endAfterSelection) {
        VisiblePosition endOfNextParagraph = endOfParagraph(endOfCurrentParagraph.next());
        if (endOfCurrentParagraph == endOfLastParagraph)
            setEndingSelection(VisibleSelection(originalSelectionEnd, DOWNSTREAM));
        else
            setEndingSelection(endOfCurrentParagraph);
        
        outdentParagraph();
        
        // outdentParagraph could move more than one paragraph if the paragraph
        // is in a list item. As a result, endAfterSelection and endOfNextParagraph
        // could refer to positions no longer in the document.
        if (endAfterSelection.isNotNull() && !endAfterSelection.deepEquivalent().anchorNode()->inDocument())
            break;
            
        if (endOfNextParagraph.isNotNull() && !endOfNextParagraph.deepEquivalent().anchorNode()->inDocument()) {
            endOfCurrentParagraph = endingSelection().end();
            endOfNextParagraph = endOfParagraph(endOfCurrentParagraph.next());
        }
        endOfCurrentParagraph = endOfNextParagraph;
    }
}

void RenderTextControl::setSelectionRange(int start, int end)
{
    end = max(end, 0);
    start = min(max(start, 0), end);

    ASSERT(!document()->childNeedsAndNotInStyleRecalc());

    if (style()->visibility() == HIDDEN || !m_innerText || !m_innerText->renderer() || !m_innerText->renderBox()->height()) {
        cacheSelection(start, end);
        return;
    }
    VisiblePosition startPosition = visiblePositionForIndex(start);
    VisiblePosition endPosition;
    if (start == end)
        endPosition = startPosition;
    else
        endPosition = visiblePositionForIndex(end);

    // startPosition and endPosition can be null position for example when
    // "-webkit-user-select: none" style attribute is specified.
    if (startPosition.isNotNull() && endPosition.isNotNull()) {
        ASSERT(startPosition.deepEquivalent().node()->shadowAncestorNode() == node() && endPosition.deepEquivalent().node()->shadowAncestorNode() == node());
    }
    VisibleSelection newSelection = VisibleSelection(startPosition, endPosition);

    if (Frame* frame = document()->frame())
        frame->selection()->setSelection(newSelection);

    // FIXME: Granularity is stored separately on the frame, but also in the selection controller.
    // The granularity in the selection controller should be used, and then this line of code would not be needed.
    if (Frame* frame = document()->frame())
        frame->setSelectionGranularity(CharacterGranularity);
}

void IndentOutdentCommand::indentRegion(const VisiblePosition& startOfSelection, const VisiblePosition& endOfSelection)
{
    // Special case empty unsplittable elements because there's nothing to split
    // and there's nothing to move.
    Position start = startOfSelection.deepEquivalent().downstream();
    if (isAtUnsplittableElement(start)) {
        RefPtr<Element> blockquote = createIndentBlockquoteElement(document());
        insertNodeAt(blockquote, start);
        RefPtr<Element> placeholder = createBreakElement(document());
        appendNode(placeholder, blockquote);
        setEndingSelection(VisibleSelection(Position(placeholder.get(), 0), DOWNSTREAM));
        return;
    }

    RefPtr<Element> blockquoteForNextIndent;
    VisiblePosition endOfCurrentParagraph = endOfParagraph(startOfSelection);
    VisiblePosition endAfterSelection = endOfParagraph(endOfParagraph(endOfSelection).next());
    int endOfCurrentParagraphIndex = indexForVisiblePosition(endOfCurrentParagraph);
    int endAfterSelectionIndex = indexForVisiblePosition(endAfterSelection);

    // When indenting within a <pre> tag, we need to split each paragraph into a separate node for moveParagraphWithClones to work.
    // However, splitting text nodes can cause endOfCurrentParagraph and endAfterSelection to point to an invalid position if we
    // changed the text node it was pointing at.  So we have to reset these positions.
    int numParagraphs = countParagraphs(endOfCurrentParagraph, endAfterSelection);
    if (splitTextNodes(startOfParagraph(startOfSelection), numParagraphs + 1)) {
        RefPtr<Range> endOfCurrentParagraphRange = TextIterator::rangeFromLocationAndLength(document()->documentElement(), endOfCurrentParagraphIndex, 0, true);
        RefPtr<Range> endAfterSelectionRange = TextIterator::rangeFromLocationAndLength(document()->documentElement(), endAfterSelectionIndex, 0, true);
        if (!endOfCurrentParagraphRange.get() || !endAfterSelectionRange.get()) {
            ASSERT_NOT_REACHED();
            return;
        }
        endOfCurrentParagraph = VisiblePosition(endOfCurrentParagraphRange->startPosition(), DOWNSTREAM);
        endAfterSelection = VisiblePosition(endAfterSelectionRange->startPosition(), DOWNSTREAM);
    }

    while (endOfCurrentParagraph != endAfterSelection) {
        // Iterate across the selected paragraphs...
        VisiblePosition endOfNextParagraph = endOfParagraph(endOfCurrentParagraph.next());
        if (tryIndentingAsListItem(endOfCurrentParagraph))
            blockquoteForNextIndent = 0;
        else
            indentIntoBlockquote(endOfCurrentParagraph, endOfNextParagraph, blockquoteForNextIndent);

        // indentIntoBlockquote could move more than one paragraph if the paragraph
        // is in a list item or a table. As a result, endAfterSelection could refer to a position
        // no longer in the document.
        if (endAfterSelection.isNotNull() && !endAfterSelection.deepEquivalent().node()->inDocument())
            break;
        // Sanity check: Make sure our moveParagraph calls didn't remove endOfNextParagraph.deepEquivalent().node()
        // If somehow we did, return to prevent crashes.
        if (endOfNextParagraph.isNotNull() && !endOfNextParagraph.deepEquivalent().node()->inDocument()) {
            ASSERT_NOT_REACHED();
            return;
        }
        endOfCurrentParagraph = endOfNextParagraph;
    }   
}

void ApplyBlockElementCommand::formatSelection(const VisiblePosition& startOfSelection, const VisiblePosition& endOfSelection)
{
    // Special case empty unsplittable elements because there's nothing to split
    // and there's nothing to move.
    Position start = startOfSelection.deepEquivalent().downstream();
    if (isAtUnsplittableElement(start)) {
        RefPtr<Element> blockquote = createBlockElement();
        insertNodeAt(blockquote, start);
        RefPtr<Element> placeholder = createBreakElement(document());
        appendNode(placeholder, blockquote);
        setEndingSelection(VisibleSelection(positionBeforeNode(placeholder.get()), DOWNSTREAM, endingSelection().isDirectional()));
        return;
    }

    RefPtr<Element> blockquoteForNextIndent;
    VisiblePosition endOfCurrentParagraph = endOfParagraph(startOfSelection);
    VisiblePosition endAfterSelection = endOfParagraph(endOfParagraph(endOfSelection).next());
    m_endOfLastParagraph = endOfParagraph(endOfSelection).deepEquivalent();

    bool atEnd = false;
    Position end;
    while (endOfCurrentParagraph != endAfterSelection && !atEnd) {
        if (endOfCurrentParagraph.deepEquivalent() == m_endOfLastParagraph)
            atEnd = true;

        rangeForParagraphSplittingTextNodesIfNeeded(endOfCurrentParagraph, start, end);
        endOfCurrentParagraph = end;

        Position afterEnd = end.next();
        Node* enclosingCell = enclosingNodeOfType(start, &isTableCell);
        VisiblePosition endOfNextParagraph = endOfNextParagrahSplittingTextNodesIfNeeded(endOfCurrentParagraph, start, end);

        formatRange(start, end, m_endOfLastParagraph, blockquoteForNextIndent);

        // Don't put the next paragraph in the blockquote we just created for this paragraph unless
        // the next paragraph is in the same cell.
        if (enclosingCell && enclosingCell != enclosingNodeOfType(endOfNextParagraph.deepEquivalent(), &isTableCell))
            blockquoteForNextIndent = 0;

        // indentIntoBlockquote could move more than one paragraph if the paragraph
        // is in a list item or a table. As a result, endAfterSelection could refer to a position
        // no longer in the document.
        if (endAfterSelection.isNotNull() && !endAfterSelection.deepEquivalent().anchorNode()->inDocument())
            break;
        // Sanity check: Make sure our moveParagraph calls didn't remove endOfNextParagraph.deepEquivalent().deprecatedNode()
        // If somehow we did, return to prevent crashes.
        if (endOfNextParagraph.isNotNull() && !endOfNextParagraph.deepEquivalent().anchorNode()->inDocument()) {
            ASSERT_NOT_REACHED();
            return;
        }
        endOfCurrentParagraph = endOfNextParagraph;
    }
}

VisiblePositionRange AccessibilityObject::leftLineVisiblePositionRange(const VisiblePosition& visiblePos) const
{
    if (visiblePos.isNull())
        return VisiblePositionRange();

    // make a caret selection for the position before marker position (to make sure
    // we move off of a line start)
    VisiblePosition prevVisiblePos = visiblePos.previous();
    if (prevVisiblePos.isNull())
        return VisiblePositionRange();

    VisiblePosition startPosition = startOfLine(prevVisiblePos);

    // keep searching for a valid line start position.  Unless the VisiblePosition is at the very beginning, there should
    // always be a valid line range.  However, startOfLine will return null for position next to a floating object,
    // since floating object doesn't really belong to any line.
    // This check will reposition the marker before the floating object, to ensure we get a line start.
    if (startPosition.isNull()) {
        while (startPosition.isNull() && prevVisiblePos.isNotNull()) {
            prevVisiblePos = prevVisiblePos.previous();
            startPosition = startOfLine(prevVisiblePos);
        }
    } else
        startPosition = updateAXLineStartForVisiblePosition(startPosition);

    VisiblePosition endPosition = endOfLine(prevVisiblePos);
    return VisiblePositionRange(startPosition, endPosition);
}

int AccessibilityObject::lineForPosition(const VisiblePosition& visiblePos) const
{
    if (visiblePos.isNull() || !node())
        return -1;

    // If the position is not in the same editable region as this AX object, return -1.
    Node* containerNode = visiblePos.deepEquivalent().containerNode();
    if (!containerNode->containsIncludingShadowDOM(node()) && !node()->containsIncludingShadowDOM(containerNode))
        return -1;

    int lineCount = -1;
    VisiblePosition currentVisiblePos = visiblePos;
    VisiblePosition savedVisiblePos;

    // move up until we get to the top
    // FIXME: This only takes us to the top of the rootEditableElement, not the top of the
    // top document.
    do {
        savedVisiblePos = currentVisiblePos;
        VisiblePosition prevVisiblePos = previousLinePosition(currentVisiblePos, 0, HasEditableAXRole);
        currentVisiblePos = prevVisiblePos;
        ++lineCount;
    }  while (currentVisiblePos.isNotNull() && !(inSameLine(currentVisiblePos, savedVisiblePos)));

    return lineCount;
}

bool FormatBlockCommand::modifyRange()
{
    ASSERT(endingSelection().isRange());
    VisiblePosition visibleStart = endingSelection().visibleStart();
    VisiblePosition visibleEnd = endingSelection().visibleEnd();
    VisiblePosition startOfLastParagraph = startOfParagraph(visibleEnd);
    
    if (startOfParagraph(visibleStart) == startOfLastParagraph)
        return false;

    setEndingSelection(visibleStart);
    doApply();
    visibleStart = endingSelection().visibleStart();
    VisiblePosition nextParagraph = endOfParagraph(visibleStart).next();
    while (nextParagraph.isNotNull() && nextParagraph != startOfLastParagraph) {
        setEndingSelection(nextParagraph);
        doApply();
        nextParagraph = endOfParagraph(endingSelection().visibleStart()).next();
    }
    setEndingSelection(visibleEnd);
    doApply();
    visibleEnd = endingSelection().visibleEnd();
    setEndingSelection(Selection(visibleStart.deepEquivalent(), visibleEnd.deepEquivalent(), DOWNSTREAM));

    return true;
}

RefPtr<Range> Frame::rangeForPoint(const IntPoint& framePoint)
{
    VisiblePosition position = visiblePositionForPoint(framePoint);
    if (position.isNull())
        return nullptr;

    Position deepPosition = position.deepEquivalent();
    Text* containerText = deepPosition.containerText();
    if (!containerText || !containerText->renderer() || containerText->renderer()->style().userSelect() == SELECT_NONE)
        return nullptr;

    VisiblePosition previous = position.previous();
    if (previous.isNotNull()) {
        RefPtr<Range> previousCharacterRange = makeRange(previous, position);
        LayoutRect rect = editor().firstRectForRange(previousCharacterRange.get());
        if (rect.contains(framePoint))
            return previousCharacterRange;
    }

    VisiblePosition next = position.next();
    if (RefPtr<Range> nextCharacterRange = makeRange(position, next)) {
        LayoutRect rect = editor().firstRectForRange(nextCharacterRange.get());
        if (rect.contains(framePoint))
            return nextCharacterRange;
    }

    return nullptr;
}

VisiblePosition VisiblePosition::previous(bool stayInEditableContent) const
{
    // find first previous DOM position that is visible
    Position pos = previousVisiblePosition(m_deepPosition);
    
    // return null visible position if there is no previous visible position
    if (pos.atStart())
        return VisiblePosition();
        
    VisiblePosition prev = VisiblePosition(pos, DOWNSTREAM);
    ASSERT(prev != *this);
    
#ifndef NDEBUG
    // we should always be able to make the affinity DOWNSTREAM, because going previous from an
    // UPSTREAM position can never yield another UPSTREAM position (unless line wrap length is 0!).
    if (prev.isNotNull() && m_affinity == UPSTREAM) {
        VisiblePosition temp = prev;
        temp.setAffinity(UPSTREAM);
        ASSERT(inSameLine(temp, prev));
    }
#endif

    if (!stayInEditableContent || prev.isNull())
        return prev;
    
    Node* highestRoot = highestEditableRoot(deepEquivalent());
    
    if (!prev.deepEquivalent().node()->isAncestor(highestRoot))
        return VisiblePosition();
        
    if (highestEditableRoot(prev.deepEquivalent()) == highestRoot)
        return prev;

    return lastEditablePositionBeforePositionInRoot(prev.deepEquivalent(), highestRoot);
}

VisiblePosition VisiblePosition::previous(EditingBoundaryCrossingRule rule) const
{
    // FIXME: Support CanSkipEditingBoundary
    ASSERT(rule == CanCrossEditingBoundary || rule == CannotCrossEditingBoundary);
    // find first previous DOM position that is visible
    Position pos = previousVisuallyDistinctCandidate(m_deepPosition);
    
    // return null visible position if there is no previous visible position
    if (pos.atStartOfTree())
        return VisiblePosition();
        
    VisiblePosition prev = VisiblePosition(pos, DOWNSTREAM);
    ASSERT(prev != *this);
    
#ifndef NDEBUG
    // we should always be able to make the affinity DOWNSTREAM, because going previous from an
    // UPSTREAM position can never yield another UPSTREAM position (unless line wrap length is 0!).
    if (prev.isNotNull() && m_affinity == UPSTREAM) {
        VisiblePosition temp = prev;
        temp.setAffinity(UPSTREAM);
        ASSERT(inSameLine(temp, prev));
    }
#endif

    if (rule == CanCrossEditingBoundary)
        return prev;
    
    return honorEditingBoundaryAtOrBefore(prev);
}

void TypingCommand::markMisspellingsAfterTyping(ETypingCommand commandType)
{
    LocalFrame* frame = document().frame();
    if (!frame)
        return;

    if (!frame->spellChecker().isContinuousSpellCheckingEnabled())
        return;

    frame->spellChecker().cancelCheck();

    // Take a look at the selection that results after typing and determine whether we need to spellcheck.
    // Since the word containing the current selection is never marked, this does a check to
    // see if typing made a new word that is not in the current selection. Basically, you
    // get this by being at the end of a word and typing a space.
    VisiblePosition start(endingSelection().start(), endingSelection().affinity());
    VisiblePosition previous = start.previous();

    VisiblePosition p1 = startOfWord(previous, LeftWordIfOnBoundary);

    if (commandType == InsertParagraphSeparator) {
        VisiblePosition p2 = nextWordPosition(start);
        VisibleSelection words(p1, endOfWord(p2));
        frame->spellChecker().markMisspellingsAfterLineBreak(words);
    } else if (previous.isNotNull()) {
        VisiblePosition p2 = startOfWord(start, LeftWordIfOnBoundary);
        if (p1 != p2)
            frame->spellChecker().markMisspellingsAfterTypingToWord(p1, endingSelection());
    }
}

VisiblePositionRange AccessibilityObject::rightLineVisiblePositionRange(const VisiblePosition& visiblePos) const
{
    if (visiblePos.isNull())
        return VisiblePositionRange();

    // make sure we move off of a line end
    VisiblePosition nextVisiblePos = visiblePos.next();
    if (nextVisiblePos.isNull())
        return VisiblePositionRange();

    VisiblePosition startPosition = startOfLine(nextVisiblePos);

    // fetch for a valid line start position
    if (startPosition.isNull() ) {
        startPosition = visiblePos;
        nextVisiblePos = nextVisiblePos.next();
    } else
        startPosition = updateAXLineStartForVisiblePosition(startPosition);

    VisiblePosition endPosition = endOfLine(nextVisiblePos);

    // as long as the position hasn't reached the end of the doc,  keep searching for a valid line end position
    // Unless the VisiblePosition is at the very end, there should always be a valid line range.  However, endOfLine will
    // return null for position by a floating object, since floating object doesn't really belong to any line.
    // This check will reposition the marker after the floating object, to ensure we get a line end.
    while (endPosition.isNull() && nextVisiblePos.isNotNull()) {
        nextVisiblePos = nextVisiblePos.next();
        endPosition = endOfLine(nextVisiblePos);
    }

    return VisiblePositionRange(startPosition, endPosition);
}

VisiblePosition VisiblePosition::previous(EditingBoundaryCrossingRule rule) const
{
    Position pos = previousVisuallyDistinctCandidate(m_deepPosition);

    // return null visible position if there is no previous visible position
    if (pos.atStartOfTree())
        return VisiblePosition();

    VisiblePosition prev = VisiblePosition(pos, DOWNSTREAM);
    ASSERT(prev != *this);

#if ENABLE(ASSERT)
    // we should always be able to make the affinity DOWNSTREAM, because going previous from an
    // UPSTREAM position can never yield another UPSTREAM position (unless line wrap length is 0!).
    if (prev.isNotNull() && m_affinity == UPSTREAM) {
        VisiblePosition temp = prev;
        temp.setAffinity(UPSTREAM);
        ASSERT(inSameLine(temp, prev));
    }
#endif

    switch (rule) {
    case CanCrossEditingBoundary:
        return prev;
    case CannotCrossEditingBoundary:
        return honorEditingBoundaryAtOrBefore(prev);
    case CanSkipOverEditingBoundary:
        return skipToStartOfEditingBoundary(prev);
    }

    ASSERT_NOT_REACHED();
    return honorEditingBoundaryAtOrBefore(prev);
}

TextDirection SelectionModifier::directionOfSelection() const {
  InlineBox* startBox = nullptr;
  InlineBox* endBox = nullptr;
  // Cache the VisiblePositions because visibleStart() and visibleEnd()
  // can cause layout, which has the potential to invalidate lineboxes.
  VisiblePosition startPosition = m_selection.visibleStart();
  VisiblePosition endPosition = m_selection.visibleEnd();
  if (startPosition.isNotNull())
    startBox = computeInlineBoxPosition(startPosition).inlineBox;
  if (endPosition.isNotNull())
    endBox = computeInlineBoxPosition(endPosition).inlineBox;
  if (startBox && endBox && startBox->direction() == endBox->direction())
    return startBox->direction();

  return directionOfEnclosingBlock();
}

VisiblePosition SelectionModifier::nextWordPositionForPlatform(
    const VisiblePosition& originalPosition) {
  VisiblePosition positionAfterCurrentWord = nextWordPosition(originalPosition);

  if (frame() &&
      frame()->editor().behavior().shouldSkipSpaceWhenMovingRight()) {
    // In order to skip spaces when moving right, we advance one
    // word further and then move one word back. Given the
    // semantics of previousWordPosition() this will put us at the
    // beginning of the word following.
    VisiblePosition positionAfterSpacingAndFollowingWord =
        nextWordPosition(positionAfterCurrentWord);
    if (positionAfterSpacingAndFollowingWord.isNotNull() &&
        positionAfterSpacingAndFollowingWord.deepEquivalent() !=
            positionAfterCurrentWord.deepEquivalent())
      positionAfterCurrentWord =
          previousWordPosition(positionAfterSpacingAndFollowingWord);

    bool movingBackwardsMovedPositionToStartOfCurrentWord =
        positionAfterCurrentWord.deepEquivalent() ==
        previousWordPosition(nextWordPosition(originalPosition))
            .deepEquivalent();
    if (movingBackwardsMovedPositionToStartOfCurrentWord)
      positionAfterCurrentWord = positionAfterSpacingAndFollowingWord;
  }
  return positionAfterCurrentWord;
}