Fixed a big race condition in the server code:

* ServerApp was accessing ServerWindow::Window() (while having the app window
  lock held), but in fact, there was no guarantee it already existed, or was
  added to the Desktop.
* Therefore, the Window() semantics have changed to only return a window in
  case the window exists *and* has been added to the desktop (the latter
  constraint might be lifted again, though). Therefore, it doesn't work
  for offscreen windows, and should not be used within ServerWindow code
  anymore.
* This fixes bug #686 and maybe others as well.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@17878 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/servers/app/Desktop.cpp

@@ -2021,7 +2021,7 @@ Desktop::SetViewUnderMouse(const WindowLayer* window, int32 viewToken)
 int32
 Desktop::ViewUnderMouse(const WindowLayer* window)
 {
-	if (fWindowUnderMouse == window)
+	if (window != NULL && fWindowUnderMouse == window)
 		return fViewUnderMouse;
 
 	return B_NULL_TOKEN;
@@ -2086,16 +2086,18 @@ Desktop::WindowAction(int32 windowToken, int32 action)
 	LockAllWindows();
 
 	::ServerWindow* serverWindow;
+	WindowLayer* window;
 	if (BPrivate::gDefaultTokens.GetToken(windowToken,
-			B_SERVER_TOKEN, (void**)&serverWindow) != B_OK) {
+			B_SERVER_TOKEN, (void**)&serverWindow) != B_OK
+		|| (window = serverWindow->Window()) == NULL) {
 		UnlockAllWindows();
 		return;
 	}
 
 	if (action == B_BRING_TO_FRONT
-		&& !serverWindow->Window()->IsMinimized()) {
+		&& !window->IsMinimized()) {
 		// the window is visible, we just need to make it the front window
-		ActivateWindow(serverWindow->Window());
+		ActivateWindow(window);
 	} else
 		serverWindow->NotifyMinimize(action == B_MINIMIZE_WINDOW);
 

src/servers/app/ServerApp.cpp

@@ -271,9 +271,9 @@ ServerApp::_HasWindowUnderMouse()
 	BAutolock locker(fWindowListLock);
 	
 	for (int32 i = fWindowList.CountItems(); i-- > 0;) {
-		ServerWindow* window = fWindowList.ItemAt(i);
+		ServerWindow* serverWindow = fWindowList.ItemAt(i);
 
-		if (fDesktop->ViewUnderMouse(window->Window()) != B_NULL_TOKEN)
+		if (fDesktop->ViewUnderMouse(serverWindow->Window()) != B_NULL_TOKEN)
 			return true;
 	}
 
@@ -439,7 +439,10 @@ ServerApp::_DispatchMessage(int32 code, BPrivate::LinkReceiver& link)
 			if (fWindowListLock.Lock()) {
 				for (int32 i = fWindowList.CountItems(); i-- > 0;) {
 					ServerWindow* serverWindow = fWindowList.ItemAt(i);
+
 					WindowLayer* window = serverWindow->Window();
+					if (window == NULL || window->IsOffscreenWindow())
+						continue;
 
 					if (window->Feel() == kWindowScreenFeel)
 						fDesktop->SetWindowFeel(window, B_NORMAL_WINDOW_FEEL);
@@ -2479,12 +2482,15 @@ ServerApp::InWorkspace(int32 index) const
 	// TODO: support initial application workspace!
 
 	for (int32 i = fWindowList.CountItems(); i-- > 0;) {
-		ServerWindow* window = fWindowList.ItemAt(i);
-		const WindowLayer* layer = window->Window();
+		ServerWindow* serverWindow = fWindowList.ItemAt(i);
+
+		const WindowLayer* window = serverWindow->Window();
+		if (window == NULL || window->IsOffscreenWindow())
+			continue;
 
 		// only normal and unhidden windows count
 
-		if (layer->IsNormal() && !layer->IsHidden() && layer->InWorkspace(index))
+		if (window->IsNormal() && !window->IsHidden() && window->InWorkspace(index))
 			return true;
 	}
 
@@ -2503,13 +2509,16 @@ ServerApp::Workspaces() const
 	// value everytime a window has closed or changed workspaces
 
 	for (int32 i = fWindowList.CountItems(); i-- > 0;) {
-		ServerWindow* window = fWindowList.ItemAt(i);
-		const WindowLayer* layer = window->Window();
+		ServerWindow* serverWindow = fWindowList.ItemAt(i);
+
+		const WindowLayer* window = serverWindow->Window();
+		if (window == NULL || window->IsOffscreenWindow())
+			continue;
 
 		// only normal and unhidden windows count
 
-		if (layer->IsNormal() && !layer->IsHidden())
-			workspaces |= layer->Workspaces();
+		if (window->IsNormal() && !window->IsHidden())
+			workspaces |= window->Workspaces();
 	}
 
 	// TODO: add initial application workspace!

src/servers/app/ServerWindow.cpp

@@ -151,6 +151,7 @@ ServerWindow::ServerWindow(const char *title, ServerApp *app,
 	fDesktop(app->GetDesktop()),
 	fServerApp(app),
 	fWindowLayer(NULL),
+	fWindowAddedToDesktop(false),
 
 	fClientTeam(app->ClientTeam()),
 
@@ -187,14 +188,16 @@ ServerWindow::~ServerWindow()
 {
 	STRACE(("ServerWindow(%s@%p):~ServerWindow()\n", fTitle, this));
 
-	if (!fWindowLayer->IsOffscreenWindow())
+	if (!fWindowLayer->IsOffscreenWindow()) {
+		fWindowAddedToDesktop = false;
 		fDesktop->RemoveWindow(fWindowLayer);
-
-	delete fWindowLayer;
+	}
 
 	if (App() != NULL)
 		App()->RemoveWindow(this);
 
+	delete fWindowLayer;
+
 	free(fTitle);
 	delete_port(fMessagePort);
 
@@ -243,8 +246,10 @@ ServerWindow::Init(BRect frame, window_look look, window_feel feel,
 	if (!fWindowLayer)
 		return B_NO_MEMORY;
 
-	if (!fWindowLayer->IsOffscreenWindow())
+	if (!fWindowLayer->IsOffscreenWindow()) {
 		fDesktop->AddWindow(fWindowLayer);
+		fWindowAddedToDesktop = true;
+	}
 
 	return B_OK;
 }
@@ -459,10 +464,19 @@ ServerWindow::GetInfo(window_info& info)
 }
 
 
+/*!
+	Returns the ServerWindow's WindowLayer, if it exists and has been
+	added to the Desktop already.
+	In other words, you cannot assume this method will always give you
+	a valid pointer.
+*/
 WindowLayer*
 ServerWindow::Window() const
 {
 	// TODO: ensure desktop is locked!
+	if (!fWindowAddedToDesktop)
+		return NULL;
+
 	return fWindowLayer;
 }
 
@@ -833,7 +847,7 @@ fDesktop->LockSingleWindow();
 			STRACE(("ServerWindow %s: Message AS_WINDOW_RESIZE %.1f, %.1f\n",
 				Title(), xResizeBy, yResizeBy));
 
-			if (Window()->IsResizing()) {
+			if (fWindowLayer->IsResizing()) {
 				// While the user resizes the window, we ignore
 				// pragmatically set window bounds
 				fLink.StartMessage(B_BUSY);
@@ -857,7 +871,7 @@ fDesktop->LockSingleWindow();
 			STRACE(("ServerWindow %s: Message AS_WINDOW_MOVE: %.1f, %.1f\n",
 				Title(), xMoveBy, yMoveBy));
 
-			if (Window()->IsDragging()) {
+			if (fWindowLayer->IsDragging()) {
 				// While the user moves the window, we ignore
 				// pragmatically set window positions
 				fLink.StartMessage(B_BUSY);

src/servers/app/ServerWindow.h

@@ -136,6 +136,7 @@ private:
 			::Desktop*			fDesktop;
 			ServerApp*			fServerApp;
 			WindowLayer*		fWindowLayer;
+			bool				fWindowAddedToDesktop;
 
 			team_id				fClientTeam;