compositeeditcommand.cpp

来自「linux下开源浏览器WebKit的源码,市面上的很多商用浏览器都是移植自Web」· C++ 代码 · 共 1,041 行 · 第 1/3 页

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

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

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

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

static inline bool isWhitespace(UChar c)
{
    return c == noBreakSpace || c == ' ' || c == '\n' || c == '\t';
}

// FIXME: Doesn't go into text nodes that contribute adjacent text (siblings, cousins, etc).
void CompositeEditCommand::rebalanceWhitespaceAt(const Position& position)
{
    Node* node = position.node();
    if (!node || !node->isTextNode())
        return;
    Text* textNode = static_cast<Text*>(node);    
    
    if (textNode->length() == 0)
        return;
    RenderObject* renderer = textNode->renderer();
    if (renderer && !renderer->style()->collapseWhiteSpace())
        return;
        
    String text = textNode->data();
    ASSERT(!text.isEmpty());

    int offset = position.offset();
    // If neither text[offset] nor text[offset - 1] are some form of whitespace, do nothing.
    if (!isWhitespace(text[offset])) {
        offset--;
        if (offset < 0 || !isWhitespace(text[offset]))
            return;
    }
    
    // Set upstream and downstream to define the extent of the whitespace surrounding text[offset].
    int upstream = offset;
    while (upstream > 0 && isWhitespace(text[upstream - 1]))
        upstream--;
    
    int downstream = offset;
    while ((unsigned)downstream + 1 < text.length() && isWhitespace(text[downstream + 1]))
        downstream++;
    
    int length = downstream - upstream + 1;
    ASSERT(length > 0);
    
    VisiblePosition visibleUpstreamPos(Position(position.node(), upstream));
    VisiblePosition visibleDownstreamPos(Position(position.node(), downstream + 1));
    
    String string = text.substring(upstream, length);
    String rebalancedString = stringWithRebalancedWhitespace(string,
    // FIXME: Because of the problem mentioned at the top of this function, we must also use nbsps at the start/end of the string because
    // this function doesn't get all surrounding whitespace, just the whitespace in the current text node.
                                                             isStartOfParagraph(visibleUpstreamPos) || upstream == 0, 
                                                             isEndOfParagraph(visibleDownstreamPos) || (unsigned)downstream == text.length() - 1);
    
    if (string != rebalancedString)
        replaceTextInNode(textNode, upstream, length, rebalancedString);
}

void CompositeEditCommand::prepareWhitespaceAtPositionForSplit(Position& position)
{
    Node* node = position.node();
    if (!node || !node->isTextNode())
        return;
    Text* textNode = static_cast<Text*>(node);    
    
    if (textNode->length() == 0)
        return;
    RenderObject* renderer = textNode->renderer();
    if (renderer && !renderer->style()->collapseWhiteSpace())
        return;

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

    VisiblePosition visiblePos(position);
    VisiblePosition previousVisiblePos(visiblePos.previous());
    Position previous(previousVisiblePos.deepEquivalent());
    
    if (isCollapsibleWhitespace(previousVisiblePos.characterAfter()) && previous.node()->isTextNode() && !previous.node()->hasTagName(brTag))
        replaceTextInNode(static_cast<Text*>(previous.node()), previous.offset(), 1, nonBreakingSpaceString());
    if (isCollapsibleWhitespace(visiblePos.characterAfter()) && position.node()->isTextNode() && !position.node()->hasTagName(brTag))
        replaceTextInNode(static_cast<Text*>(position.node()), position.offset(), 1, nonBreakingSpaceString());
}

void CompositeEditCommand::rebalanceWhitespace()
{
    VisibleSelection selection = endingSelection();
    if (selection.isNone())
        return;
        
    rebalanceWhitespaceAt(selection.start());
    if (selection.isRange())
        rebalanceWhitespaceAt(selection.end());
}

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

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

    InlineTextBox* box = textRenderer->firstTextBox();
    if (!box) {
        // whole text node is empty
        removeNode(textNode);
        return;    
    }
    
    unsigned length = textNode->length();
    if (start >= length || end > length)
        return;

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

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

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

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

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

    if (Range::compareBoundaryPoints(start, end) >= 0)
        return;

    Node* next;
    for (Node* node = start.node(); node; node = next) {
        next = node->traverseNextNode();
        if (node->isTextNode()) {
            Text* textNode = static_cast<Text*>(node);
            int startOffset = node == start.node() ? start.offset() : 0;
            int endOffset = node == end.node() ? end.offset() : textNode->length();
            deleteInsignificantText(textNode, startOffset, endOffset);
        }
        if (node == end.node())
            break;
    }
}

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

PassRefPtr<Node> CompositeEditCommand::appendBlockPlaceholder(PassRefPtr<Element> container)
{
    if (!container)
        return 0;
    
    // Should assert isBlockFlow || isInlineFlow when deletion improves. See 4244964.
    ASSERT(container->renderer());

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

PassRefPtr<Node> CompositeEditCommand::insertBlockPlaceholder(const Position& pos)
{
    if (pos.isNull())
        return 0;

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

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

PassRefPtr<Node> CompositeEditCommand::addBlockPlaceholderIfNeeded(Element* container)
{
    if (!container)
        return 0;

    updateLayout();

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

    return 0;
}

// Removes '\n's and brs that will collapse when content is inserted just before them.
// FIXME: We shouldn't really have to remove placeholders, but removing them is a workaround for 9661.
void CompositeEditCommand::removePlaceholderAt(const VisiblePosition& visiblePosition)
{
    if (visiblePosition.isNull())
        return;
        
    Position p = visiblePosition.deepEquivalent().downstream();
    // If a br or '\n' is at the end of a block and not at the start of a paragraph,
    // then it is superfluous, so adding content before a br or '\n' that is at
    // the start of a paragraph will render it superfluous.
    // FIXME: This doesn't remove placeholders at the end of anonymous blocks.
    if (isEndOfBlock(visiblePosition) && isStartOfParagraph(visiblePosition)) {
        if (p.node()->hasTagName(brTag) && p.offset() == 0)
            removeNode(p.node());
        else if (lineBreakExistsAtPosition(visiblePosition))
            deleteTextFromNode(static_cast<Text*>(p.node()), p.offset(), 1);
    }
}

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

// If the paragraph is not entirely within it's own block, create one and move the paragraph into 
// it, and return that block.  Otherwise return 0.
PassRefPtr<Node> CompositeEditCommand::moveParagraphContentsToNewBlockIfNecessary(const Position& pos)
{
    if (pos.isNull())
        return 0;
    
    updateLayout();
    
    // It's strange that this function is responsible for verifying that pos has not been invalidated
    // by an earlier call to this function.  The caller, applyBlockStyle, should do this.
    VisiblePosition visiblePos(pos, VP_DEFAULT_AFFINITY);
    VisiblePosition visibleParagraphStart(startOfParagraph(visiblePos));
    VisiblePosition visibleParagraphEnd = endOfParagraph(visiblePos);
    VisiblePosition next = visibleParagraphEnd.next();
    VisiblePosition visibleEnd = next.isNotNull() ? next : visibleParagraphEnd;
    
    Position upstreamStart = visibleParagraphStart.deepEquivalent().upstream();
    Position upstreamEnd = visibleEnd.deepEquivalent().upstream();

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

    // Perform some checks to see if we need to perform work in this function.
    if (isBlock(upstreamStart.node())) {
        // If the block is the root editable element, always move content to a new block,
        // since it is illegal to modify attributes on the root editable element for editing.
        if (upstreamStart.node() == editableRootForPosition(upstreamStart)) {
            // If the block is the root editable element and there is nothing insde of it, create a new
            // block but don't try and move content into it, since there's nothing to move.
            if (upstreamStart == upstreamEnd)
                return insertNewDefaultParagraphElementAt(upstreamStart);
        } else if (isBlock(upstreamEnd.node())) {
            if (!upstreamEnd.node()->isDescendantOf(upstreamStart.node())) {
                // If the paragraph end is a descendant of paragraph start, then we need to run
                // the rest of this function. If not, we can bail here.
                return 0;
            }
        }
        else if (enclosingBlock(upstreamEnd.node()) != upstreamStart.node()) {
            // The visibleEnd.  It must be an ancestor of the paragraph start.
            // We can bail as we have a full block to work with.
            ASSERT(upstreamStart.node()->isDescendantOf(enclosingBlock(upstreamEnd.node())));
            return 0;
        }
        else if (isEndOfDocument(visibleEnd)) {
            // At the end of the document. We can bail here as well.
            return 0;
        }
    }

    RefPtr<Node> newBlock = insertNewDefaultParagraphElementAt(upstreamStart);
    
    moveParagraphs(visibleParagraphStart, visibleParagraphEnd, VisiblePosition(Position(newBlock.get(), 0)));
    
    return newBlock.release();
}

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