deleteselectioncommand.cpp

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{
    if (!m_mergeBlocksAfterDelete) {
        if (m_pruneStartBlockIfNecessary) {
            // Make sure that the ending position isn't inside the block we're about to prune.
            m_endingPosition = m_downstreamEnd;
            // We aren't going to merge into the start block, so remove it if it's empty.
            prune(m_upstreamStart.node());
            // Removing the start block during a deletion is usually an indication that we need
            // a placeholder, but not in this case.
            m_needPlaceholder = false;
        }
        return;
    }
    
    // It shouldn't have been asked to both try and merge content into the start block and prune it.
    ASSERT(!m_pruneStartBlockIfNecessary);

    // FIXME: Deletion should adjust selection endpoints as it removes nodes so that we never get into this state (4099839).
    if (!m_downstreamEnd.node()->inDocument() || !m_upstreamStart.node()->inDocument())
         return;
         
    // FIXME: The deletion algorithm shouldn't let this happen.
    if (Range::compareBoundaryPoints(m_upstreamStart, m_downstreamEnd) > 0)
        return;
        
    // FIXME: Merging will always be unnecessary in this case, but we really bail here because this is a case where
    // deletion commonly fails to adjust its endpoints, which would cause the visible position comparison below to false negative.
    if (m_endBlock == m_startBlock)
        return;
        
    VisiblePosition startOfParagraphToMove(m_downstreamEnd);
    VisiblePosition mergeDestination(m_upstreamStart);
    
    // m_downstreamEnd's block has been emptied out by deletion.  There is no content inside of it to
    // move, so just remove it.
    Element* endBlock = static_cast<Element*>(enclosingBlock(m_downstreamEnd.node()));
    if (!startOfParagraphToMove.deepEquivalent().node() || !endBlock->contains(startOfParagraphToMove.deepEquivalent().node())) {
        removeNode(enclosingBlock(m_downstreamEnd.node()));
        return;
    }
    
    // We need to merge into m_upstreamStart's block, but it's been emptied out and collapsed by deletion.
    if (!mergeDestination.deepEquivalent().node() || !mergeDestination.deepEquivalent().node()->isDescendantOf(m_upstreamStart.node()->enclosingBlockFlowElement())) {
        insertNodeAt(createBreakElement(document()).get(), m_upstreamStart);
        mergeDestination = VisiblePosition(m_upstreamStart);
    }
    
    if (mergeDestination == startOfParagraphToMove)
        return;
        
    VisiblePosition endOfParagraphToMove = endOfParagraph(startOfParagraphToMove);
    
    if (mergeDestination == endOfParagraphToMove)
        return;
    
    // The rule for merging into an empty block is: only do so if its farther to the right.
    // FIXME: Consider RTL.
    // FIXME: handleSpecialCaseBRDelete prevents us from getting here in a case like <ul><li>foo<br><br></li></ul>^foo
    if (isStartOfParagraph(mergeDestination) && startOfParagraphToMove.absoluteCaretBounds().x() > mergeDestination.absoluteCaretBounds().x()) {
        ASSERT(mergeDestination.deepEquivalent().downstream().node()->hasTagName(brTag));
        removeNodeAndPruneAncestors(mergeDestination.deepEquivalent().downstream().node());
        m_endingPosition = startOfParagraphToMove.deepEquivalent();
        return;
    }
    
    RefPtr<Range> range = Range::create(document(), rangeCompliantEquivalent(startOfParagraphToMove.deepEquivalent()), rangeCompliantEquivalent(endOfParagraphToMove.deepEquivalent()));
    RefPtr<Range> rangeToBeReplaced = Range::create(document(), rangeCompliantEquivalent(mergeDestination.deepEquivalent()), rangeCompliantEquivalent(mergeDestination.deepEquivalent()));
    if (!document()->frame()->editor()->client()->shouldMoveRangeAfterDelete(range.get(), rangeToBeReplaced.get()))
        return;
    
    // moveParagraphs will insert placeholders if it removes blocks that would require their use, don't let block
    // removals that it does cause the insertion of *another* placeholder.
    bool needPlaceholder = m_needPlaceholder;
    moveParagraph(startOfParagraphToMove, endOfParagraphToMove, mergeDestination);
    m_needPlaceholder = needPlaceholder;
    // The endingPosition was likely clobbered by the move, so recompute it (moveParagraph selects the moved paragraph).
    m_endingPosition = endingSelection().start();
}

void DeleteSelectionCommand::removePreviouslySelectedEmptyTableRows()
{
    if (m_endTableRow && m_endTableRow->inDocument() && m_endTableRow != m_startTableRow) {
        Node* row = m_endTableRow->previousSibling();
        while (row && row != m_startTableRow) {
            RefPtr<Node> previousRow = row->previousSibling();
            if (isTableRowEmpty(row))
                // Use a raw removeNode, instead of DeleteSelectionCommand's, because
                // that won't remove rows, it only empties them in preparation for this function.
                CompositeEditCommand::removeNode(row);
            row = previousRow.get();
        }
    }
    
    // Remove empty rows after the start row.
    if (m_startTableRow && m_startTableRow->inDocument() && m_startTableRow != m_endTableRow) {
        Node* row = m_startTableRow->nextSibling();
        while (row && row != m_endTableRow) {
            RefPtr<Node> nextRow = row->nextSibling();
            if (isTableRowEmpty(row))
                CompositeEditCommand::removeNode(row);
            row = nextRow.get();
        }
    }
    
    if (m_endTableRow && m_endTableRow->inDocument() && m_endTableRow != m_startTableRow)
        if (isTableRowEmpty(m_endTableRow.get())) {
            // Don't remove m_endTableRow if it's where we're putting the ending selection.
            if (!m_endingPosition.node()->isDescendantOf(m_endTableRow.get())) {
                // FIXME: We probably shouldn't remove m_endTableRow unless it's fully selected, even if it is empty.
                // We'll need to start adjusting the selection endpoints during deletion to know whether or not m_endTableRow
                // was fully selected here.
                CompositeEditCommand::removeNode(m_endTableRow.get());
            }
        }
}

void DeleteSelectionCommand::calculateTypingStyleAfterDelete()
{
    if (!m_typingStyle)
        return;
        
    // Compute the difference between the style before the delete and the style now
    // after the delete has been done. Set this style on the frame, so other editing
    // commands being composed with this one will work, and also cache it on the command,
    // so the Frame::appliedEditing can set it after the whole composite command 
    // has completed.
    
    // If we deleted into a blockquote, but are now no longer in a blockquote, use the alternate typing style
    if (m_deleteIntoBlockquoteStyle && !nearestMailBlockquote(m_endingPosition.node()))
        m_typingStyle = m_deleteIntoBlockquoteStyle;
    m_deleteIntoBlockquoteStyle = 0;
    
    RefPtr<CSSComputedStyleDeclaration> endingStyle = computedStyle(m_endingPosition.node());
    endingStyle->diff(m_typingStyle.get());
    if (!m_typingStyle->length())
        m_typingStyle = 0;
    VisiblePosition visibleEnd(m_endingPosition);
    if (m_typingStyle && 
        isStartOfParagraph(visibleEnd) &&
        isEndOfParagraph(visibleEnd) &&
        lineBreakExistsAtPosition(visibleEnd)) {
        // Apply style to the placeholder that is now holding open the empty paragraph. 
        // This makes sure that the paragraph has the right height, and that the paragraph 
        // takes on the right style and retains it even if you move the selection away and
        // then move it back (which will clear typing style).

        setEndingSelection(visibleEnd);
        applyStyle(m_typingStyle.get(), EditActionUnspecified);
        // applyStyle can destroy the placeholder that was at m_endingPosition if it needs to 
        // move it, but it will set an endingSelection() at [movedPlaceholder, 0] if it does so.
        m_endingPosition = endingSelection().start();
        m_typingStyle = 0;
    }
    // This is where we've deleted all traces of a style but not a whole paragraph (that's handled above).
    // In this case if we start typing, the new characters should have the same style as the just deleted ones,
    // but, if we change the selection, come back and start typing that style should be lost.  Also see 
    // preserveTypingStyle() below.
    document()->frame()->setTypingStyle(m_typingStyle.get());
}

void DeleteSelectionCommand::clearTransientState()
{
    m_selectionToDelete = VisibleSelection();
    m_upstreamStart.clear();
    m_downstreamStart.clear();
    m_upstreamEnd.clear();
    m_downstreamEnd.clear();
    m_endingPosition.clear();
    m_leadingWhitespace.clear();
    m_trailingWhitespace.clear();
}

void DeleteSelectionCommand::doApply()
{
    // If selection has not been set to a custom selection when the command was created,
    // use the current ending selection.
    if (!m_hasSelectionToDelete)
        m_selectionToDelete = endingSelection();
    
    if (!m_selectionToDelete.isRange())
        return;

    // If the deletion is occurring in a text field, and we're not deleting to replace the selection, then let the frame call across the bridge to notify the form delegate. 
    if (!m_replace) {
        Node* startNode = m_selectionToDelete.start().node();
        Node* ancestorNode = startNode ? startNode->shadowAncestorNode() : 0;
        if (ancestorNode && ancestorNode->hasTagName(inputTag)
                && static_cast<HTMLInputElement*>(ancestorNode)->isTextField()
                && ancestorNode->focused())
            document()->frame()->textWillBeDeletedInTextField(static_cast<Element*>(ancestorNode));
    }

    // save this to later make the selection with
    EAffinity affinity = m_selectionToDelete.affinity();
    
    Position downstreamEnd = m_selectionToDelete.end().downstream();
    m_needPlaceholder = isStartOfParagraph(m_selectionToDelete.visibleStart()) &&
                        isEndOfParagraph(m_selectionToDelete.visibleEnd()) &&
                        !lineBreakExistsAtPosition(m_selectionToDelete.visibleEnd());
    if (m_needPlaceholder) {
        // Don't need a placeholder when deleting a selection that starts just before a table
        // and ends inside it (we do need placeholders to hold open empty cells, but that's
        // handled elsewhere).
        if (Node* table = isLastPositionBeforeTable(m_selectionToDelete.visibleStart()))
            if (m_selectionToDelete.end().node()->isDescendantOf(table))
                m_needPlaceholder = false;
    }
        
    
    // set up our state
    initializePositionData();

    // Delete any text that may hinder our ability to fixup whitespace after the delete
    deleteInsignificantTextDownstream(m_trailingWhitespace);    

    saveTypingStyleState();
    
    // deleting just a BR is handled specially, at least because we do not
    // want to replace it with a placeholder BR!
    if (handleSpecialCaseBRDelete()) {
        calculateTypingStyleAfterDelete();
        setEndingSelection(VisibleSelection(m_endingPosition, affinity));
        clearTransientState();
        rebalanceWhitespace();
        return;
    }
    
    handleGeneralDelete();
    
    fixupWhitespace();
    
    mergeParagraphs();
    
    removePreviouslySelectedEmptyTableRows();
    
    RefPtr<Node> placeholder = m_needPlaceholder ? createBreakElement(document()).get() : 0;
    
    if (placeholder)
        insertNodeAt(placeholder.get(), m_endingPosition);

    rebalanceWhitespaceAt(m_endingPosition);

    calculateTypingStyleAfterDelete();
    
    setEndingSelection(VisibleSelection(m_endingPosition, affinity));
    clearTransientState();
}

EditAction DeleteSelectionCommand::editingAction() const
{
    // Note that DeleteSelectionCommand is also used when the user presses the Delete key,
    // but in that case there's a TypingCommand that supplies the editingAction(), so
    // the Undo menu correctly shows "Undo Typing"
    return EditActionCut;
}

// Normally deletion doesn't preserve the typing style that was present before it.  For example,
// type a character, Bold, then delete the character and start typing.  The Bold typing style shouldn't
// stick around.  Deletion should preserve a typing style that *it* sets, however.
bool DeleteSelectionCommand::preservesTypingStyle() const
{
    return m_typingStyle;
}

} // namespace WebCore