Implement MouseEvent buttons attribute.

Source/core/events/MouseEvent.cpp

Index: Source/core/events/MouseEvent.cpp
diff --git a/Source/core/events/MouseEvent.cpp b/Source/core/events/MouseEvent.cpp
index b875392efae6270299157517467d31203ea4265d..5f125575472df6d60a0d3ad9de611202e5607618 100644
--- a/Source/core/events/MouseEvent.cpp
+++ b/Source/core/events/MouseEvent.cpp
@@ -40,6 +40,7 @@ MouseEventInit::MouseEventInit()
     , shiftKey(false)
     , metaKey(false)
     , button(0)
+    , buttons(0)
     , relatedTarget(nullptr)
 {
 }
@@ -61,24 +62,27 @@ PassRefPtrWillBeRawPtr<MouseEvent> MouseEvent::create(const AtomicString& eventT
         eventType, isBubbling, isCancelable, view,
         detail, event.globalPosition().x(), event.globalPosition().y(), event.position().x(), event.position().y(),
         event.movementDelta().x(), event.movementDelta().y(),
-        event.ctrlKey(), event.altKey(), event.shiftKey(), event.metaKey(), event.button(),
+        event.ctrlKey(), event.altKey(), event.shiftKey(), event.metaKey(), event.button(), event.modifiers(),
         relatedTarget, nullptr, false, event.syntheticEventType());
 }
 
 PassRefPtrWillBeRawPtr<MouseEvent> MouseEvent::create(const AtomicString& type, bool canBubble, bool cancelable, PassRefPtrWillBeRawPtr<AbstractView> view,
     int detail, int screenX, int screenY, int pageX, int pageY,
     int movementX, int movementY,
-    bool ctrlKey, bool altKey, bool shiftKey, bool metaKey, unsigned short button,
+    bool ctrlKey, bool altKey, bool shiftKey, bool metaKey,
+    unsigned short button, unsigned modifiers,
     PassRefPtrWillBeRawPtr<EventTarget> relatedTarget, PassRefPtrWillBeRawPtr<DataTransfer> dataTransfer, bool isSimulated, PlatformMouseEvent::SyntheticEventType syntheticEventType)
 {
     return adoptRefWillBeNoop(new MouseEvent(type, canBubble, cancelable, view,
         detail, screenX, screenY, pageX, pageY,
         movementX, movementY,
-        ctrlKey, altKey, shiftKey, metaKey, button, relatedTarget, dataTransfer, isSimulated, syntheticEventType));
+        ctrlKey, altKey, shiftKey, metaKey, button, modifiers,
+        relatedTarget, dataTransfer, isSimulated, syntheticEventType));
 }
 
 MouseEvent::MouseEvent()
     : m_button(0)
+    , m_buttons(0)
     , m_buttonDown(false)
 {
 }
@@ -87,13 +91,14 @@ MouseEvent::MouseEvent(const AtomicString& eventType, bool canBubble, bool cance
     int detail, int screenX, int screenY, int pageX, int pageY,
     int movementX, int movementY,
     bool ctrlKey, bool altKey, bool shiftKey, bool metaKey,
-    unsigned short button, PassRefPtrWillBeRawPtr<EventTarget> relatedTarget,
+    unsigned short button, unsigned modifiers, PassRefPtrWillBeRawPtr<EventTarget> relatedTarget,
     PassRefPtrWillBeRawPtr<DataTransfer> dataTransfer, bool isSimulated, PlatformMouseEvent::SyntheticEventType syntheticEventType)
     : MouseRelatedEvent(eventType, canBubble, cancelable, view, detail, IntPoint(screenX, screenY),
                         IntPoint(pageX, pageY),
                         IntPoint(movementX, movementY),
                         ctrlKey, altKey, shiftKey, metaKey, isSimulated)
     , m_button(button == (unsigned short)-1 ? 0 : button)
+    , m_buttons(modifiersToButtons(eventType, button, modifiers))
     , m_buttonDown(button != (unsigned short)-1)
     , m_relatedTarget(relatedTarget)
     , m_dataTransfer(dataTransfer)
@@ -107,6 +112,7 @@ MouseEvent::MouseEvent(const AtomicString& eventType, const MouseEventInit& init
         IntPoint(0 /* movementX */, 0 /* movementY */),
         initializer.ctrlKey, initializer.altKey, initializer.shiftKey, initializer.metaKey, false /* isSimulated */)
     , m_button(initializer.button == (unsigned short)-1 ? 0 : initializer.button)
+    , m_buttons(initializer.buttons == (unsigned short)-1 ? 0 : initializer.buttons)
     , m_buttonDown(initializer.button != (unsigned short)-1)
     , m_relatedTarget(initializer.relatedTarget)
     , m_dataTransfer(nullptr)
@@ -118,10 +124,31 @@ MouseEvent::~MouseEvent()
 {
 }
 
+unsigned short MouseEvent::modifiersToButtons(const AtomicString& type, unsigned short button, unsigned modifiers)
+{
+    const unsigned buttonToModifier[] = {
+        PlatformEvent::LeftButtonDown,
+        PlatformEvent::MiddleButtonDown,
+        PlatformEvent::RightButtonDown
+    };
+    if (type == EventTypeNames::mouseup)

[Rick Byers, 2014/11/25 17:44:28]

I don't think checking for mouseup here is sufficient, this logic also applies
to other events triggered as a result of mouseup (eg. click, dblclick).  I
suggest you do the modifier clearing stuff sooner on the PlatformMouseEvent -
eg. at the top of  EventHandler::handleMouseReleaseEvent (but that would require
you to make a copy you can modify) or maybe best in
PlatformMouseEventBuilder::PlatformMouseEventBuilder.

Also please add a comment since this is a little subtle.  Eg. something like:
// The MouseEvent spec requires that buttons indicates the state immediately
after the event takes place.  To ensure consistency between platforms here, we
explicitly clear the button that is in the process of being released.

[zino, 2014/11/28 12:29:28]

Done.

+        modifiers &= ~buttonToModifier[button];
+
+    unsigned short buttons = 0;
+    if (modifiers & PlatformEvent::LeftButtonDown)
+        buttons |= 1;
+    if (modifiers & PlatformEvent::RightButtonDown)
+        buttons |= 2;
+    if (modifiers & PlatformEvent::MiddleButtonDown)
+        buttons |= 4;
+
+    return buttons;
+}
+
 void MouseEvent::initMouseEvent(const AtomicString& type, bool canBubble, bool cancelable, PassRefPtrWillBeRawPtr<AbstractView> view,
                                 int detail, int screenX, int screenY, int clientX, int clientY,
                                 bool ctrlKey, bool altKey, bool shiftKey, bool metaKey,
-                                unsigned short button, PassRefPtrWillBeRawPtr<EventTarget> relatedTarget)
+                                unsigned short button, PassRefPtrWillBeRawPtr<EventTarget> relatedTarget, unsigned short buttons)
 {
     if (dispatched())
         return;
@@ -136,6 +163,7 @@ void MouseEvent::initMouseEvent(const AtomicString& type, bool canBubble, bool c
     m_button = button == (unsigned short)-1 ? 0 : button;
     m_buttonDown = button != (unsigned short)-1;
     m_relatedTarget = relatedTarget;
+    m_buttons = buttons;
 
     initCoordinates(IntPoint(clientX, clientY));
 
@@ -205,7 +233,7 @@ SimulatedMouseEvent::~SimulatedMouseEvent()
 }
 
 SimulatedMouseEvent::SimulatedMouseEvent(const AtomicString& eventType, PassRefPtrWillBeRawPtr<AbstractView> view, PassRefPtrWillBeRawPtr<Event> underlyingEvent)
-    : MouseEvent(eventType, true, true, view, 0, 0, 0, 0, 0, 0, 0, false, false, false, false, 0,
+    : MouseEvent(eventType, true, true, view, 0, 0, 0, 0, 0, 0, 0, false, false, false, false, 0, 0,
         nullptr, nullptr, true, PlatformMouseEvent::RealOrIndistinguishable)
 {
     if (UIEventWithKeyState* keyStateEvent = findEventWithKeyState(underlyingEvent.get())) {
@@ -272,9 +300,9 @@ bool MouseEventDispatchMediator::dispatchEvent(EventDispatcher* dispatcher) cons
     // as a separate event in other DOM-compliant browsers like Firefox, and so we do the same.
     RefPtrWillBeRawPtr<MouseEvent> doubleClickEvent = MouseEvent::create();
     doubleClickEvent->initMouseEvent(EventTypeNames::dblclick, event()->bubbles(), event()->cancelable(), event()->view(),
-                                     event()->detail(), event()->screenX(), event()->screenY(), event()->clientX(), event()->clientY(),
-                                     event()->ctrlKey(), event()->altKey(), event()->shiftKey(), event()->metaKey(),
-                                     event()->button(), relatedTarget);
+        event()->detail(), event()->screenX(), event()->screenY(), event()->clientX(), event()->clientY(),
+        event()->ctrlKey(), event()->altKey(), event()->shiftKey(), event()->metaKey(),
+        event()->button(), relatedTarget, event()->buttons());
     if (event()->defaultHandled())
         doubleClickEvent->setDefaultHandled();
     EventDispatcher::dispatchEvent(dispatcher->node(), MouseEventDispatchMediator::create(doubleClickEvent));