C++ RenderObject::canBeSelectionLeaf方法代码示例

void RenderView::setSelection(RenderObject* start, int startPos, RenderObject* end, int endPos, SelectionPaintInvalidationMode blockPaintInvalidationMode)
{
    // This code makes no assumptions as to if the rendering tree is up to date or not
    // and will not try to update it. Currently clearSelection calls this
    // (intentionally) without updating the rendering tree as it doesn't care.
    // Other callers may want to force recalc style before calling this.

    // Make sure both our start and end objects are defined.
    // Check www.msnbc.com and try clicking around to find the case where this happened.
    if ((start && !end) || (end && !start))
        return;

    // Just return if the selection hasn't changed.
    if (m_selectionStart == start && m_selectionStartPos == startPos &&
        m_selectionEnd == end && m_selectionEndPos == endPos)
        return;

    // Record the old selected objects.  These will be used later
    // when we compare against the new selected objects.
    int oldStartPos = m_selectionStartPos;
    int oldEndPos = m_selectionEndPos;

    // Objects each have a single selection rect to examine.
    typedef WillBeHeapHashMap<RawPtrWillBeMember<RenderObject>, SelectionState > SelectedObjectMap;
    SelectedObjectMap oldSelectedObjects;
    // FIXME: |newSelectedObjects| doesn't really need to store the SelectionState, it's just more convenient
    // to have it use the same data structure as |oldSelectedObjects|.
    SelectedObjectMap newSelectedObjects;

    // Blocks contain selected objects and fill gaps between them, either on the left, right, or in between lines and blocks.
    // In order to get the paint invalidation rect right, we have to examine left, middle, and right rects individually, since otherwise
    // the union of those rects might remain the same even when changes have occurred.
    typedef WillBeHeapHashMap<RawPtrWillBeMember<RenderBlock>, SelectionState > SelectedBlockMap;
    SelectedBlockMap oldSelectedBlocks;
    // FIXME: |newSelectedBlocks| doesn't really need to store the SelectionState, it's just more convenient
    // to have it use the same data structure as |oldSelectedBlocks|.
    SelectedBlockMap newSelectedBlocks;

    RenderObject* os = m_selectionStart;
    RenderObject* stop = rendererAfterPosition(m_selectionEnd, m_selectionEndPos);
    bool exploringBackwards = false;
    bool continueExploring = os && (os != stop);
    while (continueExploring) {
        if ((os->canBeSelectionLeaf() || os == m_selectionStart || os == m_selectionEnd) && os->selectionState() != SelectionNone) {
            // Blocks are responsible for painting line gaps and margin gaps.  They must be examined as well.
            oldSelectedObjects.set(os, os->selectionState());
            if (blockPaintInvalidationMode == PaintInvalidationNewXOROld) {
                RenderBlock* cb = os->containingBlock();
                while (cb && !cb->isRenderView()) {
                    SelectedBlockMap::AddResult result = oldSelectedBlocks.add(cb, cb->selectionState());
                    if (!result.isNewEntry)
                        break;
                    cb = cb->containingBlock();
                }
            }
        }

        os = getNextOrPrevRenderObjectBasedOnDirection(os, stop, continueExploring, exploringBackwards);
    }

    // Now clear the selection.
    SelectedObjectMap::iterator oldObjectsEnd = oldSelectedObjects.end();
    for (SelectedObjectMap::iterator i = oldSelectedObjects.begin(); i != oldObjectsEnd; ++i)
        i->key->setSelectionStateIfNeeded(SelectionNone);

    // set selection start and end
    m_selectionStart = start;
    m_selectionStartPos = startPos;
    m_selectionEnd = end;
    m_selectionEndPos = endPos;

    // Update the selection status of all objects between m_selectionStart and m_selectionEnd
    if (start && start == end)
        start->setSelectionStateIfNeeded(SelectionBoth);
    else {
        if (start)
            start->setSelectionStateIfNeeded(SelectionStart);
        if (end)
            end->setSelectionStateIfNeeded(SelectionEnd);
    }

    RenderObject* o = start;
    stop = rendererAfterPosition(end, endPos);

    while (o && o != stop) {
        if (o != start && o != end && o->canBeSelectionLeaf())
            o->setSelectionStateIfNeeded(SelectionInside);
        o = o->nextInPreOrder();
    }

    layer()->clearBlockSelectionGapsBounds();

    // Now that the selection state has been updated for the new objects, walk them again and
    // put them in the new objects list.
    o = start;
    exploringBackwards = false;
    continueExploring = o && (o != stop);
    while (continueExploring) {
        if ((o->canBeSelectionLeaf() || o == start || o == end) && o->selectionState() != SelectionNone) {
            newSelectedObjects.set(o, o->selectionState());
//.........这里部分代码省略.........

void RenderView::setSelection(RenderObject* start, int startPos, RenderObject* end, int endPos, SelectionRepaintMode blockRepaintMode)
{
    // Make sure both our start and end objects are defined.
    // Check www.msnbc.com and try clicking around to find the case where this happened.
    if ((start && !end) || (end && !start))
        return;

    // Just return if the selection hasn't changed.
    if (m_selectionStart == start && m_selectionStartPos == startPos &&
        m_selectionEnd == end && m_selectionEndPos == endPos)
        return;

    // Record the old selected objects.  These will be used later
    // when we compare against the new selected objects.
    int oldStartPos = m_selectionStartPos;
    int oldEndPos = m_selectionEndPos;

    // Objects each have a single selection rect to examine.
    typedef HashMap<RenderObject*, RenderSelectionInfo*> SelectedObjectMap;
    SelectedObjectMap oldSelectedObjects;
    SelectedObjectMap newSelectedObjects;

    // Blocks contain selected objects and fill gaps between them, either on the left, right, or in between lines and blocks.
    // In order to get the repaint rect right, we have to examine left, middle, and right rects individually, since otherwise
    // the union of those rects might remain the same even when changes have occurred.
    typedef HashMap<RenderBlock*, RenderBlockSelectionInfo*> SelectedBlockMap;
    SelectedBlockMap oldSelectedBlocks;
    SelectedBlockMap newSelectedBlocks;

    RenderObject* os = m_selectionStart;
    RenderObject* stop = rendererAfterPosition(m_selectionEnd, m_selectionEndPos);
    while (os && os != stop) {
        if ((os->canBeSelectionLeaf() || os == m_selectionStart || os == m_selectionEnd) && os->selectionState() != SelectionNone) {
            // Blocks are responsible for painting line gaps and margin gaps.  They must be examined as well.
            oldSelectedObjects.set(os, new RenderSelectionInfo(os, true));
            if (blockRepaintMode == RepaintNewXOROld) {
                RenderBlock* cb = os->containingBlock();
                while (cb && !cb->isRenderView()) {
                    RenderBlockSelectionInfo* blockInfo = oldSelectedBlocks.get(cb);
                    if (blockInfo)
                        break;
                    oldSelectedBlocks.set(cb, new RenderBlockSelectionInfo(cb));
                    cb = cb->containingBlock();
                }
            }
        }

        os = os->nextInPreOrder();
    }

    // Now clear the selection.
    SelectedObjectMap::iterator oldObjectsEnd = oldSelectedObjects.end();
    for (SelectedObjectMap::iterator i = oldSelectedObjects.begin(); i != oldObjectsEnd; ++i)
        i->first->setSelectionState(SelectionNone);

    // set selection start and end
    m_selectionStart = start;
    m_selectionStartPos = startPos;
    m_selectionEnd = end;
    m_selectionEndPos = endPos;

    // Update the selection status of all objects between m_selectionStart and m_selectionEnd
    if (start && start == end)
        start->setSelectionState(SelectionBoth);
    else {
        if (start)
            start->setSelectionState(SelectionStart);
        if (end)
            end->setSelectionState(SelectionEnd);
    }

    RenderObject* o = start;
    stop = rendererAfterPosition(end, endPos);

    while (o && o != stop) {
        if (o != start && o != end && o->canBeSelectionLeaf())
            o->setSelectionState(SelectionInside);
        o = o->nextInPreOrder();
    }

    m_layer->clearBlockSelectionGapsBounds();

    // Now that the selection state has been updated for the new objects, walk them again and
    // put them in the new objects list.
    o = start;
    while (o && o != stop) {
        if ((o->canBeSelectionLeaf() || o == start || o == end) && o->selectionState() != SelectionNone) {
            newSelectedObjects.set(o, new RenderSelectionInfo(o, true));
            RenderBlock* cb = o->containingBlock();
            while (cb && !cb->isRenderView()) {
                RenderBlockSelectionInfo* blockInfo = newSelectedBlocks.get(cb);
                if (blockInfo)
                    break;
                newSelectedBlocks.set(cb, new RenderBlockSelectionInfo(cb));
                cb = cb->containingBlock();
            }
        }

        o = o->nextInPreOrder();
    }
//.........这里部分代码省略.........