* Reworked EventDispatcher::SendFakeMouseMoved() after an idea by Stephan

that solves most app_server locking headaches: it now works asynchronously,
  and therefore doesn't need to lock the EventDispatcher anymore.
* EventStreams now allow to inject messages into the stream to allow the above
  functionality.
* InputServerStream::GetNextEvent() no longer returns when there is no event.
* Desktop::ActivateWindow() now locks all windows before checking the
  workspaces of the windows, fixing a race condition that could lead to
  Window::Foremost() being called for a window that isn't on the current
  workspace, leading to a crash.
* I currently cannot access Trac, but I recall there should be an open bug
  report about this.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@28224 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/servers/app/Desktop.cpp

@@ -1326,8 +1326,6 @@ Desktop::RemoveWorkspacesView(WorkspacesView* view)
 
 	This has only to be done in case the view changed without user interaction,
 	ie. because of a workspace change or a closing window.
-
-	Windows must not be locked when calling this method.
 */
 void
 Desktop::_SendFakeMouseMoved(Window* window)
@@ -1520,6 +1518,9 @@ Desktop::ActivateWindow(Window* window)
 
 	// TODO: take care about floating windows
 
+	if (!LockAllWindows())
+		return;
+
 	bool windowOnOtherWorkspace = !window->InWorkspace(fCurrentWorkspace);
 	if (windowOnOtherWorkspace) {
 		if ((window->Flags() & B_NO_WORKSPACE_ACTIVATION) == 0
@@ -1535,13 +1536,12 @@ Desktop::ActivateWindow(Window* window)
 					break;
 				}
 			}
-		} else if ((window->Flags() & B_NOT_ANCHORED_ON_ACTIVATE) == 0)
+		} else if ((window->Flags() & B_NOT_ANCHORED_ON_ACTIVATE) == 0) {
+			UnlockAllWindows();
 			return;
+		}
 	}
 
-	if (!LockAllWindows())
-		return;
-
 	if (windowOnOtherWorkspace
 		&& (window->Flags() & B_NOT_ANCHORED_ON_ACTIVATE) != 0) {
 		// bring the window to the current workspace
@@ -1554,12 +1554,7 @@ Desktop::ActivateWindow(Window* window)
 		// Unlike WindowAction(), this is called from the application itself,
 		// so we will just unminimize the window here.
 		window->SetMinimized(false);
-		UnlockAllWindows();
-
 		ShowWindow(window);
-
-		if (!LockAllWindows())
-			return;
 	}
 
 	if (window == FrontWindow()) {
@@ -2368,7 +2363,7 @@ Desktop::ViewUnderMouse(const Window* window)
 }
 
 
-Window *
+Window*
 Desktop::FindWindowByClientToken(int32 token, team_id teamID)
 {
 	for (Window *window = fAllWindows.FirstWindow(); window != NULL;
@@ -2383,6 +2378,19 @@ Desktop::FindWindowByClientToken(int32 token, team_id teamID)
 }
 
 
+::EventTarget*
+Desktop::FindTarget(BMessenger& messenger)
+{
+	for (Window *window = fAllWindows.FirstWindow(); window != NULL;
+			window = window->NextWindow(kAllWindowList)) {
+		if (window->EventTarget().Messenger() == messenger)
+			return &window->EventTarget();
+	}
+
+	return NULL;
+}
+
+
 void
 Desktop::MinimizeApplication(team_id team)
 {

src/servers/app/Desktop.h

@@ -167,6 +167,7 @@ class Desktop : public MessageLooper, public ScreenOwner {
 
 		Window*					FindWindowByClientToken(int32 token,
 									team_id teamID);
+		EventTarget*			FindTarget(BMessenger& messenger);
 
 #if USE_MULTI_LOCKER
 		bool					LockSingleWindow()

src/servers/app/EventDispatcher.cpp

@@ -17,6 +17,7 @@
 #include "ServerBitmap.h"
 
 #include <MessagePrivate.h>
+#include <MessengerPrivate.h>
 #include <ServerProtocol.h>
 #include <TokenSpace.h>
 
@@ -72,6 +73,8 @@ struct event_listener {
 
 static const char* kTokenName = "_token";
 
+static const uint32 kFakeMouseMoved = 'fake';
+
 static const float kMouseMovedImportance = 0.1f;
 static const float kMouseTransitImportance = 1.0f;
 static const float kStandardImportance = 0.9f;
@@ -494,7 +497,44 @@ EventDispatcher::GetMouse(BPoint& where, int32& buttons)
 void
 EventDispatcher::SendFakeMouseMoved(EventTarget& target, int32 viewToken)
 {
-	BAutolock _(this);
+	if (fStream == NULL)
+		return;
+
+	BMessage* fakeMove = new BMessage(kFakeMouseMoved);
+	if (fakeMove == NULL)
+		return;
+
+	fakeMove->AddMessenger("target", target.Messenger());
+	fakeMove->AddInt32("view_token", viewToken);
+
+	fStream->InsertEvent(fakeMove);
+}
+
+
+void
+EventDispatcher::_SendFakeMouseMoved(BMessage* message)
+{
+	BMessenger target;
+	int32 viewToken;
+	if (message->FindInt32("view_token", &viewToken) != B_OK
+		|| message->FindMessenger("target", &target) != B_OK)
+		return;
+
+	if (fDesktop == NULL)
+		return;
+
+	// Check if the target is still valid
+	::EventTarget* eventTarget = NULL;
+
+	fDesktop->LockSingleWindow();
+
+	if (target.IsValid())
+		eventTarget = fDesktop->FindTarget(target);
+
+	fDesktop->UnlockSingleWindow();
+
+	if (eventTarget == NULL)
+		return;
 
 	BMessage moved(B_MOUSE_MOVED);
 	moved.AddPoint("screen_where", fLastCursorPosition);
@@ -504,7 +544,7 @@ EventDispatcher::SendFakeMouseMoved(EventTarget& target, int32 viewToken)
 		moved.AddMessage("be:drag_message", &fDragMessage);
 
 	if (fPreviousMouseTarget != NULL
-		&& fPreviousMouseTarget != &target) {
+		&& fPreviousMouseTarget->Messenger() != target) {
 		_AddTokens(&moved, fPreviousMouseTarget, B_POINTER_EVENTS);
 		_SendMessage(fPreviousMouseTarget->Messenger(), &moved,
 			kMouseTransitImportance);
@@ -515,8 +555,9 @@ EventDispatcher::SendFakeMouseMoved(EventTarget& target, int32 viewToken)
 	moved.AddInt32("_view_token", viewToken);
 		// this only belongs to the new target
 
-	_SendMessage(target.Messenger(), &moved, kMouseTransitImportance);
+	_SendMessage(target, &moved, kMouseTransitImportance);
-	fPreviousMouseTarget = &target;
+
+	fPreviousMouseTarget = eventTarget;
 }
 
 
@@ -718,12 +759,6 @@ EventDispatcher::_EventLoop()
 {
 	BMessage* event;
 	while (fStream->GetNextEvent(&event)) {
-		if (event == NULL) {
-			// may happen in out of memory situations or junk at the port
-			// we can't do anything about those yet
-			continue;
-		}
-
 		BAutolock _(this);
 		fLastUpdate = system_time();
 
@@ -734,6 +769,9 @@ EventDispatcher::_EventLoop()
 		bool addedTokens = false;
 
 		switch (event->what) {
+			case kFakeMouseMoved:
+				_SendFakeMouseMoved(event);
+				break;
 			case B_MOUSE_MOVED:
 			{
 				BPoint where;

src/servers/app/EventDispatcher.h

@@ -102,6 +102,7 @@ class EventDispatcher : public BLocker {
 		status_t _Run();
 		void _Unset();
 
+		void _SendFakeMouseMoved(BMessage* message);
 		bool _SendMessage(BMessenger& messenger, BMessage* message,
 				float importance);
 

src/servers/app/EventStream.cpp

@@ -120,7 +120,7 @@ InputServerStream::UpdateScreenBounds(BRect bounds)
 bool
 InputServerStream::GetNextEvent(BMessage** _event)
 {
-	if (fEvents.IsEmpty()) {
+	while (fEvents.IsEmpty()) {
 		// wait for new events
 		BMessage* event;
 		status_t status = _MessageFromPort(&event);
@@ -191,6 +191,21 @@ InputServerStream::GetNextCursorPosition(BPoint &where)
 }
 
 
+status_t
+InputServerStream::InsertEvent(BMessage* event)
+{
+	fEvents.AddMessage(event);
+	status_t status = write_port_etc(fPort, 'insm', NULL, 0, B_RELATIVE_TIMEOUT,
+		0);
+	if (status == B_BAD_PORT_ID)
+		return status;
+
+	// If the port is full, we obviously don't care to report this, as we
+	// already placed our message.
+	return B_OK;
+}
+
+
 BMessage*
 InputServerStream::PeekLatestMouseMoved()
 {
@@ -231,6 +246,10 @@ InputServerStream::_MessageFromPort(BMessage** _message, bigtime_t timeout)
 		// this will cause GetNextEvent() to return false
 		return B_BAD_PORT_ID;
 	}
+	if (code == 'insm') {
+		// a message has been inserted into our queue
+		return B_INTERRUPTED;
+	}
 
 	// we have the message, now let's unflatten it
 

src/servers/app/EventStream.h

@@ -32,6 +32,8 @@ class EventStream {
 		virtual bool GetNextEvent(BMessage** _event) = 0;
 		virtual bool GetNextCursorPosition(BPoint& where);
 
+		virtual status_t InsertEvent(BMessage* event) = 0;
+
 		virtual BMessage* PeekLatestMouseMoved() = 0;
 };
 
@@ -55,6 +57,8 @@ class InputServerStream : public EventStream {
 		virtual bool GetNextEvent(BMessage** _event);
 		virtual bool GetNextCursorPosition(BPoint& where);
 
+		virtual status_t InsertEvent(BMessage* event);
+
 		virtual BMessage* PeekLatestMouseMoved();
 
 	private: