eventhandler.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 1,735 行 · 第 1/5 页

#if ENABLE(SVG)
    if (m_frame->document()->isSVGDocument() &&
       static_cast<SVGDocument*>(m_frame->document())->zoomAndPanEnabled()) {
        if (event.event().shiftKey() && singleClick) {
            m_svgPan = true;
            static_cast<SVGDocument*>(m_frame->document())->startPan(event.event().pos());
            return true;
        }
    }
#endif

    // We don't do this at the start of mouse down handling,
    // because we don't want to do it until we know we didn't hit a widget.
    if (singleClick)
        focusDocumentView();

    Node* innerNode = event.targetNode();

    m_mousePressNode = innerNode;
    m_dragStartPos = event.event().pos();

    bool swallowEvent = false;
    if (event.event().button() == LeftButton || event.event().button() == MiddleButton) {
        m_frame->selection()->setCaretBlinkingSuspended(true);
        m_mousePressed = true;
        m_beganSelectingText = false;

        if (event.event().clickCount() == 2)
            swallowEvent = handleMousePressEventDoubleClick(event);
        else if (event.event().clickCount() >= 3)
            swallowEvent = handleMousePressEventTripleClick(event);
        else
            swallowEvent = handleMousePressEventSingleClick(event);
    }
    
    m_mouseDownMayStartAutoscroll = m_mouseDownMayStartSelect || 
        (m_mousePressNode && m_mousePressNode->renderBox() && m_mousePressNode->renderBox()->canBeProgramaticallyScrolled(true));

   return swallowEvent;
}

bool EventHandler::handleMouseDraggedEvent(const MouseEventWithHitTestResults& event)
{
    if (handleDrag(event))
        return true;

    if (!m_mousePressed)
        return false;

    Node* targetNode = event.targetNode();
    if (event.event().button() != LeftButton || !targetNode || !targetNode->renderer())
        return false;

#if PLATFORM(MAC) // FIXME: Why does this assertion fire on other platforms?
    ASSERT(m_mouseDownMayStartSelect || m_mouseDownMayStartAutoscroll);
#endif

    m_mouseDownMayStartDrag = false;

    if (m_mouseDownMayStartAutoscroll && !m_panScrollInProgress) {            
        // If the selection is contained in a layer that can scroll, that layer should handle the autoscroll
        // Otherwise, let the bridge handle it so the view can scroll itself.
        RenderObject* renderer = targetNode->renderer();
        while (renderer && (!renderer->isBox() || !toRenderBox(renderer)->canBeProgramaticallyScrolled(false))) {
            if (!renderer->parent() && renderer->node() == renderer->document() && renderer->document()->ownerElement())
                renderer = renderer->document()->ownerElement()->renderer();
            else
                renderer = renderer->parent();
        }
        
        if (renderer) {
            m_autoscrollInProgress = true;
            handleAutoscroll(renderer);
        }
        
        m_mouseDownMayStartAutoscroll = false;
    }
    
    updateSelectionForMouseDrag(targetNode, event.localPoint());
    return true;
}
    
bool EventHandler::eventMayStartDrag(const PlatformMouseEvent& event) const
{
    // This is a pre-flight check of whether the event might lead to a drag being started.  Be careful
    // that its logic needs to stay in sync with handleMouseMoveEvent() and the way we setMouseDownMayStartDrag
    // in handleMousePressEvent
    
    if (!m_frame->contentRenderer() || !m_frame->contentRenderer()->hasLayer()
        || event.button() != LeftButton || event.clickCount() != 1)
        return false;
    
    bool DHTMLFlag;
    bool UAFlag;
    allowDHTMLDrag(DHTMLFlag, UAFlag);
    if (!DHTMLFlag && !UAFlag)
        return false;
    
    HitTestRequest request(HitTestRequest::ReadOnly);
    HitTestResult result(m_frame->view()->windowToContents(event.pos()));
    m_frame->contentRenderer()->layer()->hitTest(request, result);
    bool srcIsDHTML;
    return result.innerNode() && result.innerNode()->renderer()->draggableNode(DHTMLFlag, UAFlag, result.point().x(), result.point().y(), srcIsDHTML);
}

void EventHandler::updateSelectionForMouseDrag()
{
    FrameView* view = m_frame->view();
    if (!view)
        return;
    RenderView* renderer = m_frame->contentRenderer();
    if (!renderer)
        return;
    RenderLayer* layer = renderer->layer();
    if (!layer)
        return;

    HitTestRequest request(HitTestRequest::ReadOnly |
                           HitTestRequest::Active |
                           HitTestRequest::MouseMove);
    HitTestResult result(view->windowToContents(m_currentMousePosition));
    layer->hitTest(request, result);
    updateSelectionForMouseDrag(result.innerNode(), result.localPoint());
}

void EventHandler::updateSelectionForMouseDrag(Node* targetNode, const IntPoint& localPoint)
{
    if (!m_mouseDownMayStartSelect)
        return;

    if (!targetNode)
        return;

    RenderObject* targetRenderer = targetNode->renderer();
    if (!targetRenderer)
        return;
        
    if (!canMouseDragExtendSelect(targetNode))
        return;

    VisiblePosition targetPosition(targetRenderer->positionForPoint(localPoint));

    // Don't modify the selection if we're not on a node.
    if (targetPosition.isNull())
        return;

    // Restart the selection if this is the first mouse move. This work is usually
    // done in handleMousePressEvent, but not if the mouse press was on an existing selection.
    VisibleSelection newSelection = m_frame->selection()->selection();

#if ENABLE(SVG)
    // Special case to limit selection to the containing block for SVG text.
    // FIXME: Isn't there a better non-SVG-specific way to do this?
    if (Node* selectionBaseNode = newSelection.base().node())
        if (RenderObject* selectionBaseRenderer = selectionBaseNode->renderer())
            if (selectionBaseRenderer->isSVGText())
                if (targetNode->renderer()->containingBlock() != selectionBaseRenderer->containingBlock())
                    return;
#endif

    if (!m_beganSelectingText) {
        m_beganSelectingText = true;
        newSelection = VisibleSelection(targetPosition);
    }

    newSelection.setExtent(targetPosition);
    if (m_frame->selectionGranularity() != CharacterGranularity)
        newSelection.expandUsingGranularity(m_frame->selectionGranularity());

    if (m_frame->shouldChangeSelection(newSelection)) {
        m_frame->selection()->setLastChangeWasHorizontalExtension(false);
        m_frame->selection()->setSelection(newSelection);
    }
}
    
bool EventHandler::handleMouseUp(const MouseEventWithHitTestResults& event)
{
    if (eventLoopHandleMouseUp(event))
        return true;
    
    // If this was the first click in the window, we don't even want to clear the selection.
    // This case occurs when the user clicks on a draggable element, since we have to process
    // the mouse down and drag events to see if we might start a drag.  For other first clicks
    // in a window, we just don't acceptFirstMouse, and the whole down-drag-up sequence gets
    // ignored upstream of this layer.
    return eventActivatedView(event.event());
}    

bool EventHandler::handleMouseReleaseEvent(const MouseEventWithHitTestResults& event)
{
    if (m_autoscrollInProgress)
        stopAutoscrollTimer();

    if (handleMouseUp(event))
        return true;

    // Used to prevent mouseMoveEvent from initiating a drag before
    // the mouse is pressed again.
    m_frame->selection()->setCaretBlinkingSuspended(false);
    m_mousePressed = false;
    m_capturesDragging = false;
    m_mouseDownMayStartDrag = false;
    m_mouseDownMayStartSelect = false;
    m_mouseDownMayStartAutoscroll = false;
    m_mouseDownWasInSubframe = false;
  
    bool handled = false;

    // Clear the selection if the mouse didn't move after the last mouse press.
    // We do this so when clicking on the selection, the selection goes away.
    // However, if we are editing, place the caret.
    if (m_mouseDownWasSingleClickInSelection && !m_beganSelectingText
            && m_dragStartPos == event.event().pos()
            && m_frame->selection()->isRange()) {
        VisibleSelection newSelection;
        Node *node = event.targetNode();
        if (node && node->isContentEditable() && node->renderer()) {
            VisiblePosition pos = node->renderer()->positionForPoint(event.localPoint());
            newSelection = VisibleSelection(pos);
        }
        if (m_frame->shouldChangeSelection(newSelection))
            m_frame->selection()->setSelection(newSelection);

        handled = true;
    }

    m_frame->notifyRendererOfSelectionChange(true);

    m_frame->selection()->selectFrameElementInParentIfFullySelected();

    return handled;
}

void EventHandler::handleAutoscroll(RenderObject* renderer)
{
    // We don't want to trigger the autoscroll or the panScroll if it's already active
    if (m_autoscrollTimer.isActive())
        return;     

    setAutoscrollRenderer(renderer);

#if ENABLE(PAN_SCROLLING)
    if (m_panScrollInProgress) {
        m_panScrollStartPos = currentMousePosition();
        m_frame->view()->addPanScrollIcon(m_panScrollStartPos);
        // If we're not in the top frame we notify it that we are using the panScroll
        if (m_frame != m_frame->page()->mainFrame())
            m_frame->page()->mainFrame()->eventHandler()->setPanScrollInProgress(true);
    }
#endif

    startAutoscrollTimer();
}

void EventHandler::autoscrollTimerFired(Timer<EventHandler>*)
{
    RenderObject* r = autoscrollRenderer();
    if (!r || !r->isBox()) {
        stopAutoscrollTimer();
        return;
    }

    if (m_autoscrollInProgress) {
        if (!m_mousePressed) {
            stopAutoscrollTimer();
            return;
        }
        toRenderBox(r)->autoscroll();
    } else {
        // we verify that the main frame hasn't received the order to stop the panScroll
        if (!m_frame->page()->mainFrame()->eventHandler()->panScrollInProgress()) {
            stopAutoscrollTimer();
            return;
        }
#if ENABLE(PAN_SCROLLING)
        setPanScrollCursor();
        toRenderBox(r)->panScroll(m_panScrollStartPos);
#endif
    }
}

#if ENABLE(PAN_SCROLLING)
void EventHandler::setPanScrollCursor()
{
    // At the original click location we draw a 4 arrowed icon. Over this icon there won't be any scroll
    // So we don't want to change the cursor over this area
    const int noScrollRadius = 9;
    bool east = m_panScrollStartPos.x() < (m_currentMousePosition.x() - noScrollRadius);
    bool west = m_panScrollStartPos.x() > (m_currentMousePosition.x() + noScrollRadius);
    bool north = m_panScrollStartPos.y() > (m_currentMousePosition.y() + noScrollRadius);
    bool south = m_panScrollStartPos.y() < (m_currentMousePosition.y() - noScrollRadius);
         
    if (north) {
        if (east)
            m_frame->view()->setCursor(northEastPanningCursor());
        else if (west)
            m_frame->view()->setCursor(northWestPanningCursor());
        else
            m_frame->view()->setCursor(northPanningCursor());
    } else if (south) {
        if (east)
            m_frame->view()->setCursor(southEastPanningCursor());
        else if (west)
            m_frame->view()->setCursor(southWestPanningCursor());
        else
            m_frame->view()->setCursor(southPanningCursor());
    } else if (east)
        m_frame->view()->setCursor(eastPanningCursor());
    else if (west)
        m_frame->view()->setCursor(westPanningCursor());
    else
        m_frame->view()->setCursor(middlePanningCursor());
}
#endif  // ENABLE(PAN_SCROLLING)

RenderObject* EventHandler::autoscrollRenderer() const
{
    return m_autoscrollRenderer;
}

void EventHandler::updateAutoscrollRenderer()
{
    if (!m_autoscrollRenderer)
        return;

    HitTestResult hitTest = hitTestResultAtPoint(m_panScrollStartPos, true);

    if (Node* nodeAtPoint = hitTest.innerNode())
        m_autoscrollRenderer = nodeAtPoint->renderer();

    while (m_autoscrollRenderer && (!m_autoscrollRenderer->isBox() || !toRenderBox(m_autoscrollRenderer)->canBeProgramaticallyScrolled(false)))
        m_autoscrollRenderer = m_autoscrollRenderer->parent();
}

void EventHandler::setAutoscrollRenderer(RenderObject* renderer)
{
    m_autoscrollRenderer = renderer;
}

void EventHandler::allowDHTMLDrag(bool& flagDHTML, bool& flagUA) const
{
    if (!m_frame) {
        flagDHTML = false;
        flagUA = false;
        return;
    }