eventhandler.cpp

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    }

#if ENABLE(PAN_SCROLLING)
    if (m_frame->page()->mainFrame()->eventHandler()->panScrollInProgress() || m_autoscrollInProgress) {
        stopAutoscrollTimer();
        invalidateClick();
        return true;
    }
    
    if (mouseEvent.button() == MiddleButton && !mev.isOverLink()) {
        RenderObject* renderer = mev.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_panScrollInProgress = true;
            handleAutoscroll(renderer);
            invalidateClick();
            return true;
        }
   }
#endif

    m_clickCount = mouseEvent.clickCount();
    m_clickNode = mev.targetNode();
    
    RenderLayer* layer = m_clickNode->renderer() ? m_clickNode->renderer()->enclosingLayer() : 0;
    IntPoint p = m_frame->view()->windowToContents(mouseEvent.pos());
    if (layer && layer->isPointInResizeControl(p)) {
        layer->setInResizeMode(true);
        m_resizeLayer = layer;
        m_offsetFromResizeCorner = layer->offsetFromResizeCorner(p);
        invalidateClick();
        return true;
    }

    bool swallowEvent = dispatchMouseEvent(eventNames().mousedownEvent, mev.targetNode(), true, m_clickCount, mouseEvent, true);
    m_capturesDragging = !swallowEvent;

    // If the hit testing originally determined the event was in a scrollbar, refetch the MouseEventWithHitTestResults
    // in case the scrollbar widget was destroyed when the mouse event was handled.
    if (mev.scrollbar()) {
        const bool wasLastScrollBar = mev.scrollbar() == m_lastScrollbarUnderMouse.get();
        HitTestRequest request(HitTestRequest::ReadOnly |
                               HitTestRequest::Active);
        mev = prepareMouseEvent(request, mouseEvent);

        if (wasLastScrollBar && mev.scrollbar() != m_lastScrollbarUnderMouse.get())
            m_lastScrollbarUnderMouse = 0;
    }

    if (swallowEvent) {
        // scrollbars should get events anyway, even disabled controls might be scrollable
        if (mev.scrollbar())
            passMousePressEventToScrollbar(mev, mev.scrollbar());
    } else {
        // Refetch the event target node if it currently is the shadow node inside an <input> element.
        // If a mouse event handler changes the input element type to one that has a widget associated,
        // we'd like to EventHandler::handleMousePressEvent to pass the event to the widget and thus the
        // event target node can't still be the shadow node.
        if (mev.targetNode()->isShadowNode() && mev.targetNode()->shadowParentNode()->hasTagName(inputTag)) {
            HitTestRequest request(HitTestRequest::ReadOnly |
                                   HitTestRequest::Active);
            mev = prepareMouseEvent(request, mouseEvent);
        }

        Scrollbar* scrollbar = m_frame->view()->scrollbarUnderMouse(mouseEvent);
        if (!scrollbar)
            scrollbar = mev.scrollbar();
        if (scrollbar && passMousePressEventToScrollbar(mev, scrollbar))
            swallowEvent = true;
        else
            swallowEvent = handleMousePressEvent(mev);
    }

    return swallowEvent;
}

// This method only exists for platforms that don't know how to deliver 
bool EventHandler::handleMouseDoubleClickEvent(const PlatformMouseEvent& mouseEvent)
{
    RefPtr<FrameView> protector(m_frame->view());

    // We get this instead of a second mouse-up 
    m_mousePressed = false;
    m_currentMousePosition = mouseEvent.pos();

    HitTestRequest request(HitTestRequest::Active);
    MouseEventWithHitTestResults mev = prepareMouseEvent(request, mouseEvent);
    Frame* subframe = subframeForHitTestResult(mev);
    if (subframe && passMousePressEventToSubframe(mev, subframe)) {
        m_capturingMouseEventsNode = 0;
        return true;
    }

    m_clickCount = mouseEvent.clickCount();
    bool swallowMouseUpEvent = dispatchMouseEvent(eventNames().mouseupEvent, mev.targetNode(), true, m_clickCount, mouseEvent, false);

    bool swallowClickEvent = false;
    // Don't ever dispatch click events for right clicks
    if (mouseEvent.button() != RightButton && mev.targetNode() == m_clickNode)
        swallowClickEvent = dispatchMouseEvent(eventNames().clickEvent, mev.targetNode(), true, m_clickCount, mouseEvent, true);

    if (m_lastScrollbarUnderMouse)
        swallowMouseUpEvent = m_lastScrollbarUnderMouse->mouseUp();
            
    bool swallowMouseReleaseEvent = false;
    if (!swallowMouseUpEvent)
        swallowMouseReleaseEvent = handleMouseReleaseEvent(mev);

    invalidateClick();

    return swallowMouseUpEvent || swallowClickEvent || swallowMouseReleaseEvent;
}

bool EventHandler::mouseMoved(const PlatformMouseEvent& event)
{
    HitTestResult hoveredNode = HitTestResult(IntPoint());
    bool result = handleMouseMoveEvent(event, &hoveredNode);

    Page* page = m_frame->page();
    if (!page)
        return result;

    hoveredNode.setToNonShadowAncestor();
    page->chrome()->mouseDidMoveOverElement(hoveredNode, event.modifierFlags());
    page->chrome()->setToolTip(hoveredNode);
    return result;
}

bool EventHandler::handleMouseMoveEvent(const PlatformMouseEvent& mouseEvent, HitTestResult* hoveredNode)
{
    // in Radar 3703768 we saw frequent crashes apparently due to the
    // part being null here, which seems impossible, so check for nil
    // but also assert so that we can try to figure this out in debug
    // builds, if it happens.
    ASSERT(m_frame);
    if (!m_frame)
        return false;

    RefPtr<FrameView> protector(m_frame->view());
    m_currentMousePosition = mouseEvent.pos();

    if (m_hoverTimer.isActive())
        m_hoverTimer.stop();

#if ENABLE(SVG)
    if (m_svgPan) {
        static_cast<SVGDocument*>(m_frame->document())->updatePan(m_currentMousePosition);
        return true;
    }
#endif

    if (m_frameSetBeingResized)
        return dispatchMouseEvent(eventNames().mousemoveEvent, m_frameSetBeingResized.get(), false, 0, mouseEvent, false);

    // Send events right to a scrollbar if the mouse is pressed.
    if (m_lastScrollbarUnderMouse && m_mousePressed)
        return m_lastScrollbarUnderMouse->mouseMoved(m_lastScrollbarUnderMouse->transformEvent(mouseEvent));

    // Treat mouse move events while the mouse is pressed as "read-only" in prepareMouseEvent
    // if we are allowed to select.
    // This means that :hover and :active freeze in the state they were in when the mouse
    // was pressed, rather than updating for nodes the mouse moves over as you hold the mouse down.
    int hitType = HitTestRequest::MouseMove;
    if (m_mousePressed && m_mouseDownMayStartSelect)
        hitType |= HitTestRequest::ReadOnly;
    if (m_mousePressed)
        hitType |= HitTestRequest::Active;
    HitTestRequest request(hitType);
    MouseEventWithHitTestResults mev = prepareMouseEvent(request, mouseEvent);
    if (hoveredNode)
        *hoveredNode = mev.hitTestResult();

    Scrollbar* scrollbar = 0;

    if (m_resizeLayer && m_resizeLayer->inResizeMode())
        m_resizeLayer->resize(mouseEvent, m_offsetFromResizeCorner);
    else {
        if (m_frame->view())
            scrollbar = m_frame->view()->scrollbarUnderMouse(mouseEvent);

        if (!scrollbar)
            scrollbar = mev.scrollbar();

        if (m_lastScrollbarUnderMouse != scrollbar) {
            // Send mouse exited to the old scrollbar.
            if (m_lastScrollbarUnderMouse)
                m_lastScrollbarUnderMouse->mouseExited();
            m_lastScrollbarUnderMouse = m_mousePressed ? 0 : scrollbar;
        }
    }

    bool swallowEvent = false;
    RefPtr<Frame> newSubframe = m_capturingMouseEventsNode.get() ? subframeForTargetNode(m_capturingMouseEventsNode.get()) : subframeForHitTestResult(mev);
 
    // We want mouseouts to happen first, from the inside out.  First send a move event to the last subframe so that it will fire mouseouts.
    if (m_lastMouseMoveEventSubframe && m_lastMouseMoveEventSubframe->tree()->isDescendantOf(m_frame) && m_lastMouseMoveEventSubframe != newSubframe)
        passMouseMoveEventToSubframe(mev, m_lastMouseMoveEventSubframe.get());

    if (newSubframe) {
        // Update over/out state before passing the event to the subframe.
        updateMouseEventTargetNode(mev.targetNode(), mouseEvent, true);
        
        // Event dispatch in updateMouseEventTargetNode may have caused the subframe of the target
        // node to be detached from its FrameView, in which case the event should not be passed.
        if (newSubframe->view())
            swallowEvent |= passMouseMoveEventToSubframe(mev, newSubframe.get(), hoveredNode);
    } else {
        if (scrollbar && !m_mousePressed)
            scrollbar->mouseMoved(scrollbar->transformEvent(mouseEvent)); // Handle hover effects on platforms that support visual feedback on scrollbar hovering.
        if ((!m_resizeLayer || !m_resizeLayer->inResizeMode()) && !m_frame->page()->mainFrame()->eventHandler()->panScrollInProgress() && m_frame->view())
            m_frame->view()->setCursor(selectCursor(mev, scrollbar));
    }
    
    m_lastMouseMoveEventSubframe = newSubframe;

    if (swallowEvent)
        return true;
    
    swallowEvent = dispatchMouseEvent(eventNames().mousemoveEvent, mev.targetNode(), false, 0, mouseEvent, true);
    if (!swallowEvent)
        swallowEvent = handleMouseDraggedEvent(mev);

    return swallowEvent;
}

void EventHandler::invalidateClick()
{
    m_clickCount = 0;
    m_clickNode = 0;
}

bool EventHandler::handleMouseReleaseEvent(const PlatformMouseEvent& mouseEvent)
{
    RefPtr<FrameView> protector(m_frame->view());

    m_mousePressed = false;
    m_currentMousePosition = mouseEvent.pos();

#if ENABLE(SVG)
    if (m_svgPan) {
        m_svgPan = false;
        static_cast<SVGDocument*>(m_frame->document())->updatePan(m_currentMousePosition);
        return true;
    }
#endif

    if (m_frameSetBeingResized)
        return dispatchMouseEvent(eventNames().mouseupEvent, m_frameSetBeingResized.get(), true, m_clickCount, mouseEvent, false);

    if (m_lastScrollbarUnderMouse) {
        invalidateClick();
        return m_lastScrollbarUnderMouse->mouseUp();
    }

    HitTestRequest request(HitTestRequest::MouseUp);
    MouseEventWithHitTestResults mev = prepareMouseEvent(request, mouseEvent);
    Frame* subframe = m_capturingMouseEventsNode.get() ? subframeForTargetNode(m_capturingMouseEventsNode.get()) : subframeForHitTestResult(mev);
    if (subframe && passMouseReleaseEventToSubframe(mev, subframe)) {
        m_capturingMouseEventsNode = 0;
        return true;
    }

    bool swallowMouseUpEvent = dispatchMouseEvent(eventNames().mouseupEvent, mev.targetNode(), true, m_clickCount, mouseEvent, false);

    // Don't ever dispatch click events for right clicks
    bool swallowClickEvent = false;
    if (m_clickCount > 0 && mouseEvent.button() != RightButton && mev.targetNode() == m_clickNode)
        swallowClickEvent = dispatchMouseEvent(eventNames().clickEvent, mev.targetNode(), true, m_clickCount, mouseEvent, true);

    if (m_resizeLayer) {
        m_resizeLayer->setInResizeMode(false);
        m_resizeLayer = 0;
    }

    bool swallowMouseReleaseEvent = false;
    if (!swallowMouseUpEvent)
        swallowMouseReleaseEvent = handleMouseReleaseEvent(mev);

    invalidateClick();

    return swallowMouseUpEvent || swallowClickEvent || swallowMouseReleaseEvent;
}

bool EventHandler::dispatchDragEvent(const AtomicString& eventType, Node* dragTarget, const PlatformMouseEvent& event, Clipboard* clipboard)
{
    m_frame->view()->resetDeferredRepaintDelay();

    IntPoint contentsPos = m_frame->view()->windowToContents(event.pos());
    
    RefPtr<MouseEvent> me = MouseEvent::create(eventType,
        true, true, m_frame->document()->defaultView(),
        0, event.globalX(), event.globalY(), contentsPos.x(), contentsPos.y(),
        event.ctrlKey(), event.altKey(), event.shiftKey(), event.metaKey(),
        0, 0, clipboard);

    ExceptionCode ec = 0;
    dragTarget->dispatchEvent(me.get(), ec);
    return me->defaultPrevented();
}

bool EventHandler::updateDragAndDrop(const PlatformMouseEvent& event, Clipboard* clipboard)
{
    bool accept = false;

    if (!m_frame->view())
        return false;

    HitTestRequest request(HitTestRequest::ReadOnly);
    MouseEventWithHitTestResults mev = prepareMouseEvent(request, event);

    // Drag events should never go to text nodes (following IE, and proper mouseover/out dispatch)
    Node* newTarget = mev.targetNode();
    if (newTarget && newTarget->isTextNode())
        newTarget = newTarget->parentNode();
    if (newTarget)
        newTarget = newTarget->shadowAncestorNode();

    if (m_dragTarget != newTarget) {
        // FIXME: this ordering was explicitly chosen to match WinIE. However,
        // it is sometimes incorrect when dragging within subframes, as seen with
        // LayoutTests/fast/events/drag-in-frames.html.
        if (newTarget)
            if (newTarget->hasTagName(frameTag) || newTarget->hasTagName(iframeTag))
                accept = static_cast<HTMLFrameElementBase*>(newTarget)->contentFrame()->eventHandler()->updateDragAndDrop(event, clipboard);
            else
                accept = dispatchDragEvent(eventNames().dragenterEvent, newTarget, event, clipboard);
        
        if (m_dragTarget) {
            Frame* frame = (m_dragTarget->hasTagName(frameTag) || m_dragTarget->hasTagName(iframeTag)) 
                            ? static_cast<HTMLFrameElementBase*>(m_dragTarget.get())->contentFrame() : 0;
            if (frame)
                accept = frame->eventHandler()->updateDragAndDrop(event, clipboard);
            else
                dispatchDragEvent(eventNames().dragleaveEvent, m_dragTarget.get(), event, clipboard);
        }
    } else {
        if (newTarget)
            if (newTarget->hasTagName(frameTag) || newTarget->hasTagName(iframeTag))
                accept = static_cast<HTMLFrameElementBase*>(newTarget)->contentFrame()->eventHandler()->updateDragAndDrop(event, clipboard);
            else