haiku/src/servers/app/Desktop.cpp

/*
 * Copyright 2001-2006, Haiku.
 * Distributed under the terms of the MIT License.
 *
 * Authors:
 *		Adrian Oanca <adioanca@cotty.iren.ro>
 *		Stephan Aßmus <superstippi@gmx.de>
 *		Axel Dörfler, axeld@pinc-software.de
 */

/**	Class used to encapsulate desktop management */


#include "Desktop.h"

#include "AppServer.h"
#include "DesktopSettingsPrivate.h"
#include "DrawingEngine.h"
#include "HWInterface.h"
#include "InputManager.h"
#include "ServerApp.h"
#include "ServerConfig.h"
#include "ServerCursor.h"
#include "ServerScreen.h"
#include "ServerWindow.h"
#include "WindowPrivate.h"
#include "WindowLayer.h"
#include "Workspace.h"
#include "WorkspacesLayer.h"

#include <WindowInfo.h>
#include <ServerProtocol.h>

#include <DirectWindow.h>
#include <Entry.h>
#include <Message.h>
#include <MessageFilter.h>
#include <Region.h>

#include <stdio.h>

#if TEST_MODE
#	include "EventStream.h"
#endif

//#define DEBUG_DESKTOP
#ifdef DEBUG_DESKTOP
#	define STRACE(a) printf(a)
#else
#	define STRACE(a) ;
#endif


class KeyboardFilter : public EventFilter {
	public:
		KeyboardFilter(Desktop* desktop);

		virtual filter_result Filter(BMessage* message, EventTarget** _target,
			int32* _viewToken, BMessage* latestMouseMoved);

	private:
		void _UpdateFocus(int32 key, EventTarget** _target);

		Desktop*		fDesktop;
		EventTarget*	fLastFocus;
		bigtime_t		fTimestamp;
};

class MouseFilter : public EventFilter {
	public:
		MouseFilter(Desktop* desktop);

		virtual filter_result Filter(BMessage* message, EventTarget** _target,
			int32* _viewToken, BMessage* latestMouseMoved);

	private:
		Desktop*	fDesktop;
};


//	#pragma mark -


KeyboardFilter::KeyboardFilter(Desktop* desktop)
	:
	fDesktop(desktop),
	fLastFocus(NULL),
	fTimestamp(0)
{
}


void
KeyboardFilter::_UpdateFocus(int32 key, EventTarget** _target)
{
	if (!fDesktop->LockSingleWindow())
		return;

	bigtime_t now = system_time();

	EventTarget* focus = NULL;
	if (fDesktop->FocusWindow() != NULL)
		focus = &fDesktop->FocusWindow()->EventTarget();

	// TODO: this is a try to not steal focus from the current window
	//	in case you enter some text and a window pops up you haven't
	//	triggered yourself (like a pop-up window in your browser while
	//	you're typing a password in another window) - maybe this should
	//	be done differently, though (using something like B_LOCK_WINDOW_FOCUS)
	//	(at least B_WINDOW_ACTIVATED must be postponed)

	if (focus != fLastFocus && now - fTimestamp > 100000) {
		// if the time span between the key presses is very short
		// we keep our previous focus alive - this is save even
		// if the target doesn't exist anymore, as we don't reset
		// it, and the event focus passed in is always valid (or NULL)
		*_target = focus;
		fLastFocus = focus;
	}

	fDesktop->UnlockSingleWindow();

	// we always allow to switch focus after the enter key has pressed
	if (key == B_ENTER)
		fTimestamp = 0;
	else
		fTimestamp = now;
}


filter_result
KeyboardFilter::Filter(BMessage* message, EventTarget** _target,
	int32* /*_viewToken*/, BMessage* /*latestMouseMoved*/)
{
	int32 key = 0;
	int32 modifiers;

	if (message->what == B_KEY_DOWN
		&& message->FindInt32("key", &key) == B_OK
		&& message->FindInt32("modifiers", &modifiers) == B_OK) {
		// TODO: for some reason, one of the above is failing when pressing
		//	a modifier key at least with the old BMessage implementation
		//	(a message dump shows all entries, though)
		//	Try again with BMessage4!

		// Check for safe video mode (F12 + l-cmd + l-ctrl + l-shift)
		if (key == 0x0d
			&& (modifiers & (B_LEFT_COMMAND_KEY
					| B_LEFT_CONTROL_KEY | B_LEFT_SHIFT_KEY)) != 0) {
			// TODO: Set to Safe Mode in KeyboardEventHandler:B_KEY_DOWN.
			STRACE(("Safe Video Mode invoked - code unimplemented\n"));
			return B_SKIP_MESSAGE;
		}

		if (key > 0x01 && key < 0x0e) {
			// workspace change, F1-F12

#if !TEST_MODE
			if (modifiers & B_COMMAND_KEY)
#else
			if (modifiers & B_CONTROL_KEY)
#endif
			{
				STRACE(("Set Workspace %ld\n", key - 1));

				fDesktop->SetWorkspace(key - 2);
				return B_SKIP_MESSAGE;
			}
		}

		// TODO: this should be moved client side!
		// (that's how it is done in BeOS, clients could need this key for
		// different purposes - also, it's preferrable to let the client
		// write the dump within his own environment)
		if (key == 0xe) {
			// screen dump, PrintScreen
			char filename[128];
			BEntry entry;

			int32 index = 1;
			do {
				sprintf(filename, "/boot/home/screen%ld.png", index++);
				entry.SetTo(filename);
			} while(entry.Exists());

			fDesktop->GetDrawingEngine()->DumpToFile(filename);
			return B_SKIP_MESSAGE;
		}
	}

	if (message->what == B_KEY_DOWN
		|| message->what == B_MODIFIERS_CHANGED
		|| message->what == B_UNMAPPED_KEY_DOWN)
		_UpdateFocus(key, _target);

	return B_DISPATCH_MESSAGE;
}


//	#pragma mark -


MouseFilter::MouseFilter(Desktop* desktop)
	:
	fDesktop(desktop)
{
}


filter_result
MouseFilter::Filter(BMessage* message, EventTarget** _target, int32* _viewToken,
	BMessage* latestMouseMoved)
{
	BPoint where;
	if (message->FindPoint("where", &where) != B_OK)
		return B_DISPATCH_MESSAGE;

	if (!fDesktop->LockAllWindows())
		return B_DISPATCH_MESSAGE;

	int32 viewToken = B_NULL_TOKEN;

	WindowLayer* window = fDesktop->MouseEventWindow();
	if (window == NULL)
		window = fDesktop->WindowAt(where);

	if (window != NULL) {
		// dispatch event in the window layers
		switch (message->what) {
			case B_MOUSE_DOWN:
				window->MouseDown(message, where, &viewToken);
				break;

			case B_MOUSE_UP:
				window->MouseUp(message, where, &viewToken);
				fDesktop->SetMouseEventWindow(NULL);
				break;

			case B_MOUSE_MOVED:
				window->MouseMoved(message, where, &viewToken,
					latestMouseMoved == NULL || latestMouseMoved == message);
				break;
		}

		if (viewToken != B_NULL_TOKEN) {
			fDesktop->SetViewUnderMouse(window, viewToken);

			*_viewToken = viewToken;
			*_target = &window->EventTarget();
		}
	}

	if (window == NULL || viewToken == B_NULL_TOKEN) {
		// mouse is not over a window or over a decorator
		fDesktop->SetViewUnderMouse(window, B_NULL_TOKEN);
		fDesktop->SetCursor(NULL);

		*_target = NULL;
	}

	fDesktop->UnlockAllWindows();

	return B_DISPATCH_MESSAGE;
}


//	#pragma mark -


static inline uint32
workspace_to_workspaces(int32 index)
{
	return 1UL << index;
}


static inline bool
workspace_in_workspaces(int32 index, uint32 workspaces)
{
	return (workspaces & (1UL << index)) != 0;
}


//	#pragma mark -


Desktop::Desktop(uid_t userID)
	: MessageLooper("desktop"),

	fUserID(userID),
	fSettings(new DesktopSettings::Private()),
	fApplicationsLock("application list"),
	fShutdownSemaphore(-1),
	fCurrentWorkspace(0),
	fAllWindows(kAllWindowList),
	fSubsetWindows(kSubsetList),
	fWorkspacesLayer(NULL),
	fActiveScreen(NULL),
	fWindowLock("window lock"),
	fMouseEventWindow(NULL),
	fFocus(NULL),
	fFront(NULL),
	fBack(NULL)
{
	char name[B_OS_NAME_LENGTH];
	Desktop::_GetLooperName(name, sizeof(name));

	for (int32 i = 0; i < kMaxWorkspaces; i++) {
		_Windows(i).SetIndex(i);
		fWorkspaces[i].RestoreConfiguration(*fSettings->WorkspacesMessage(i));
	}

	fMessagePort = create_port(DEFAULT_MONITOR_PORT_SIZE, name);
	if (fMessagePort < B_OK)
		return;

	fLink.SetReceiverPort(fMessagePort);
	gFontManager->AttachUser(fUserID);
}


Desktop::~Desktop()
{
	delete fSettings;

	delete_port(fMessagePort);
	gFontManager->DetachUser(fUserID);
}


void
Desktop::Init()
{
	fVirtualScreen.RestoreConfiguration(*this, fSettings->WorkspacesMessage(0));

	// TODO: temporary workaround, fActiveScreen will be removed
	fActiveScreen = fVirtualScreen.ScreenAt(0);

#if TEST_MODE
	gInputManager->AddStream(new InputServerStream);
#endif
	fEventDispatcher.SetTo(gInputManager->GetStream());
	fEventDispatcher.SetHWInterface(fVirtualScreen.HWInterface());

	fEventDispatcher.SetMouseFilter(new MouseFilter(this));
	fEventDispatcher.SetKeyboardFilter(new KeyboardFilter(this));

	SetCursor(NULL);
		// this will set the default cursor

	fVirtualScreen.HWInterface()->MoveCursorTo(fVirtualScreen.Frame().Width() / 2,
		fVirtualScreen.Frame().Height() / 2);
	fVirtualScreen.HWInterface()->SetCursorVisible(true);

	// draw the background

	fScreenRegion = fVirtualScreen.Frame();

	BRegion stillAvailableOnScreen;
	_RebuildClippingForAllWindows(stillAvailableOnScreen);
	_SetBackground(stillAvailableOnScreen);
}


void
Desktop::_GetLooperName(char* name, size_t length)
{
	snprintf(name, length, "d:%d:%s", /*id*/0, /*name*/"baron");
}


void
Desktop::_PrepareQuit()
{
	// let's kill all remaining applications

	fApplicationsLock.Lock();

	int32 count = fApplications.CountItems();
	for (int32 i = 0; i < count; i++) {
		ServerApp *app = fApplications.ItemAt(i);
		team_id clientTeam = app->ClientTeam();

		app->Quit();
		kill_team(clientTeam);
	}

	// wait for the last app to die
	if (count > 0)
		acquire_sem_etc(fShutdownSemaphore, fShutdownCount, B_RELATIVE_TIMEOUT, 250000);

	fApplicationsLock.Unlock();
}


void
Desktop::_DispatchMessage(int32 code, BPrivate::LinkReceiver &link)
{
	switch (code) {
		case AS_CREATE_APP:
		{
			// Create the ServerApp to node monitor a new BApplication

			// Attached data:
			// 1) port_id - receiver port of a regular app
			// 2) port_id - client looper port - for sending messages to the client
			// 2) team_id - app's team ID
			// 3) int32 - handler token of the regular app
			// 4) char * - signature of the regular app

			// Find the necessary data
			team_id	clientTeamID = -1;
			port_id	clientLooperPort = -1;
			port_id clientReplyPort = -1;
			int32 htoken = B_NULL_TOKEN;
			char *appSignature = NULL;

			link.Read<port_id>(&clientReplyPort);
			link.Read<port_id>(&clientLooperPort);
			link.Read<team_id>(&clientTeamID);
			link.Read<int32>(&htoken);
			if (link.ReadString(&appSignature) != B_OK)
				break;

			ServerApp *app = new ServerApp(this, clientReplyPort,
				clientLooperPort, clientTeamID, htoken, appSignature);
			if (app->InitCheck() == B_OK
				&& app->Run()) {
				// add the new ServerApp to the known list of ServerApps
				fApplicationsLock.Lock();
				fApplications.AddItem(app);
				fApplicationsLock.Unlock();
			} else {
				delete app;

				// if everything went well, ServerApp::Run() will notify
				// the client - but since it didn't, we do it here
				BPrivate::LinkSender reply(clientReplyPort);
				reply.StartMessage(SERVER_FALSE);
				reply.Flush();
			}

			// This is necessary because BPortLink::ReadString allocates memory
			free(appSignature);
			break;
		}

		case AS_DELETE_APP:
		{
			// Delete a ServerApp. Received only from the respective ServerApp when a
			// BApplication asks it to quit.

			// Attached Data:
			// 1) thread_id - thread ID of the ServerApp to be deleted

			thread_id thread = -1;
			if (link.Read<thread_id>(&thread) < B_OK)
				break;

			fApplicationsLock.Lock();

			// Run through the list of apps and nuke the proper one

			int32 count = fApplications.CountItems();
			ServerApp *removeApp = NULL;

			for (int32 i = 0; i < count; i++) {
				ServerApp *app = fApplications.ItemAt(i);

				if (app != NULL && app->Thread() == thread) {
					fApplications.RemoveItemAt(i);
					removeApp = app;
					break;
				}
			}

			fApplicationsLock.Unlock();

			if (removeApp != NULL)
				removeApp->Quit(fShutdownSemaphore);

			if (fQuitting && count <= 1) {
				// wait for the last app to die
				acquire_sem_etc(fShutdownSemaphore, fShutdownCount, B_RELATIVE_TIMEOUT, 500000);
				PostMessage(kMsgQuitLooper);
			}
			break;
		}

		case AS_ACTIVATE_APP:
		{
			// Someone is requesting to activation of a certain app.

			// Attached data:
			// 1) port_id reply port
			// 2) team_id team

			status_t status;

			// get the parameters
			port_id replyPort;
			team_id team;
			if (link.Read(&replyPort) == B_OK
				&& link.Read(&team) == B_OK)
				status = _ActivateApp(team);
			else
				status = B_ERROR;

			// send the reply
			BPrivate::PortLink replyLink(replyPort);
			replyLink.StartMessage(status);
			replyLink.Flush();
			break;
		}

		case B_QUIT_REQUESTED:
			// We've been asked to quit, so (for now) broadcast to all
			// test apps to quit. This situation will occur only when the server
			// is compiled as a regular Be application.

			fApplicationsLock.Lock();
			fShutdownSemaphore = create_sem(0, "desktop shutdown");
			fShutdownCount = fApplications.CountItems();
			fApplicationsLock.Unlock();

			fQuitting = true;
			BroadcastToAllApps(AS_QUIT_APP);

			// We now need to process the remaining AS_DELETE_APP messages and
			// wait for the kMsgShutdownServer message.
			// If an application does not quit as asked, the picasso thread
			// will send us this message in 2-3 seconds.

			// if there are no apps to quit, shutdown directly
			if (fShutdownCount == 0)
				PostMessage(kMsgQuitLooper);
			break;

		default:
			printf("Desktop %d:%s received unexpected code %ld\n", 0, "baron", code);

			if (link.NeedsReply()) {
				// the client is now blocking and waiting for a reply!
				fLink.StartMessage(B_ERROR);
				fLink.Flush();
			}
			break;
	}
}


/*!
	\brief activate one of the app's windows.
*/
status_t
Desktop::_ActivateApp(team_id team)
{
	status_t status = B_BAD_TEAM_ID;

	// search for an unhidden window to give focus to

	for (WindowLayer* window = fAllWindows.FirstWindow(); window != NULL;
			window = window->NextWindow(kAllWindowList)) {
		// if window is a normal window of the team, and not hidden, 
		// we've found our target
		if (!window->IsHidden() && window->IsNormal()
			&& window->ServerWindow()->ClientTeam() == team) {
			ActivateWindow(window);
			return B_OK;
		}
	}

	return status;
}


/*!
	\brief Send a quick (no attachments) message to all applications
	
	Quite useful for notification for things like server shutdown, system 
	color changes, etc.
*/
void
Desktop::BroadcastToAllApps(int32 code)
{
	BAutolock locker(fApplicationsLock);

	for (int32 i = 0; i < fApplications.CountItems(); i++) {
		fApplications.ItemAt(i)->PostMessage(code);
	}
}


ServerCursor*
Desktop::Cursor() const
{
	return HWInterface()->Cursor();
}


void
Desktop::SetCursor(ServerCursor* newCursor)
{
	if (newCursor == NULL)
		newCursor = fCursorManager.GetCursor(B_CURSOR_DEFAULT);

	ServerCursor* oldCursor = Cursor();
	if (newCursor == oldCursor)
		return;

	HWInterface()->SetCursor(newCursor);
}


/*!
	\brief Redraws the background (ie. the desktop window, if any).
*/
void
Desktop::RedrawBackground()
{
	LockAllWindows();

	BRegion redraw;

	WindowLayer* window = _CurrentWindows().FirstWindow();
	if (window->Feel() == kDesktopWindowFeel) {
		redraw = window->VisibleContentRegion();

		// look for desktop background view, and update its background color
		// TODO: is there a better way to do this?
		ViewLayer* view = window->TopLayer();
		if (view != NULL)
			view = view->FirstChild();

		while (view) {
			if (view->IsDesktopBackground()) {
				view->SetViewColor(fWorkspaces[fCurrentWorkspace].Color());
				break;
			}
			view = view->NextSibling();
		}

		window->ProcessDirtyRegion(redraw);
	} else {
		redraw = BackgroundRegion();
		fBackgroundRegion.MakeEmpty();
		_SetBackground(redraw);
	}

	UnlockAllWindows();
}


void
Desktop::UpdateWorkspaces()
{
	// TODO: maybe this should be replaced by a SetWorkspacesCount() method

	_WindowChanged(NULL);
}


void
Desktop::SetWorkspace(int32 index)
{
	LockAllWindows();
	DesktopSettings settings(this);

	if (index < 0 || index >= settings.WorkspacesCount() || index == fCurrentWorkspace) {
		UnlockAllWindows();
		return;
	}

	int32 previousIndex = fCurrentWorkspace;

	if (fMouseEventWindow != NULL) {
		if (!fMouseEventWindow->InWorkspace(index)) {
			// the window currently being dragged will follow us to this workspace
			// if it's not already on it
			if (fMouseEventWindow->IsNormal()) {
				// but only normal windows are following
				uint32 oldWorkspaces = fMouseEventWindow->Workspaces();

				_Windows(index).AddWindow(fMouseEventWindow);
				_Windows(previousIndex).RemoveWindow(fMouseEventWindow);

				// send B_WORKSPACES_CHANGED message
				fMouseEventWindow->WorkspacesChanged(oldWorkspaces,
					fMouseEventWindow->Workspaces());
			}
		} else {
			// make sure it's frontmost
			_Windows(index).RemoveWindow(fMouseEventWindow);
			_Windows(index).AddWindow(fMouseEventWindow,
				fMouseEventWindow->Frontmost(_Windows(index).FirstWindow(), index));
		}

		fMouseEventWindow->Anchor(index).position = fMouseEventWindow->Frame().LeftTop();
	}

	// build region of windows that are no longer visible in the new workspace

	BRegion dirty;

	for (WindowLayer* window = _CurrentWindows().FirstWindow();
			window != NULL; window = window->NextWindow(previousIndex)) {
		// store current position in Workspace anchor
		window->Anchor(previousIndex).position = window->Frame().LeftTop();

		window->WorkspaceActivated(previousIndex, false);

		if (window->InWorkspace(index))
			continue;

		if (!window->IsHidden()) {
			// this window will no longer be visible
			dirty.Include(&window->VisibleRegion());
		}

		window->SetCurrentWorkspace(-1);
	}

	fCurrentWorkspace = index;

	// show windows, and include them in the changed region - but only
	// those that were not visible before (or whose position changed)

	for (WindowLayer* window = _Windows(index).FirstWindow();
			window != NULL; window = window->NextWindow(index)) {
		BPoint position = window->Anchor(index).position;

		window->SetCurrentWorkspace(index);

		if (window->IsHidden())
			continue;

		if (position == kInvalidWindowPosition) {
			// if you enter a workspace for the first time, the position
			// of the window in the previous workspace is adopted
			position = window->Frame().LeftTop();
				// TODO: make sure the window is still on-screen if it
				//	was before!
		}

		if (!window->InWorkspace(previousIndex)) {
			// This window was not visible before, make sure its frame
			// is up-to-date
			if (window->Frame().LeftTop() != position) {
				BPoint offset = position - window->Frame().LeftTop();
				window->MoveBy(offset.x, offset.y);
			}
			continue;
		}

		if (window->Frame().LeftTop() != position) {
			// the window was visible before, but its on-screen location changed
			BPoint offset = position - window->Frame().LeftTop();
			MoveWindowBy(window, offset.x, offset.y);
				// TODO: be a bit smarter than this...
		}
	}

	BRegion stillAvailableOnScreen;
	_RebuildClippingForAllWindows(stillAvailableOnScreen);
	_SetBackground(stillAvailableOnScreen);

	for (WindowLayer* window = _Windows(index).FirstWindow(); window != NULL;
			window = window->NextWindow(index)) {
		// send B_WORKSPACE_ACTIVATED message
		window->WorkspaceActivated(index, true);

		if (window->InWorkspace(previousIndex) || window == fMouseEventWindow) {
			// this window was visible before, and is already handled in the above loop
			continue;
		}

		dirty.Include(&window->VisibleRegion());
	}

	_UpdateFronts(false);
	_UpdateFloating(previousIndex, index);

	// Set new focus to the front window, but keep focus to a floating
	// window if still visible
	if (!_Windows(index).HasWindow(FocusWindow()) || !FocusWindow()->IsFloating())
		SetFocusWindow(FrontWindow());

	_WindowChanged(NULL);
	MarkDirty(dirty);

	UnlockAllWindows();

	_SendFakeMouseMoved();
}


void
Desktop::ScreenChanged(Screen* screen, bool makeDefault)
{
	// TODO: confirm that everywhere this is used,
	// the Window WriteLock is held

	// the entire screen is dirty, because we're actually
	// operating on an all new buffer in memory
	BRegion dirty(screen->Frame());
	// update our cached screen region
	fScreenRegion.Set(screen->Frame());

	BRegion background;
	_RebuildClippingForAllWindows(background);

	fBackgroundRegion.MakeEmpty();
		// makes sure that the complete background is redrawn
	_SetBackground(background);

	// figure out dirty region
	dirty.Exclude(&background);
	_TriggerWindowRedrawing(dirty);

	// send B_SCREEN_CHANGED to windows on that screen
	BMessage update(B_SCREEN_CHANGED);
	update.AddInt64("when", real_time_clock_usecs());
	update.AddRect("frame", screen->Frame());
	update.AddInt32("mode", screen->ColorSpace());

	// TODO: currently ignores the screen argument!
	for (WindowLayer* window = fAllWindows.FirstWindow(); window != NULL;
			window = window->NextWindow(kAllWindowList)) {
		window->ServerWindow()->SendMessageToClient(&update);
	}

	if (makeDefault) {
		// store settings
		BMessage settings;
		fVirtualScreen.StoreConfiguration(settings);
		fWorkspaces[fCurrentWorkspace].StoreConfiguration(settings);

		fSettings->SetWorkspacesMessage(fCurrentWorkspace, settings);
		fSettings->Save(kWorkspacesSettings);
	}
}


//	#pragma mark - Methods for WindowLayer manipulation


WindowList&
Desktop::_CurrentWindows()
{
	return fWorkspaces[fCurrentWorkspace].Windows();
}


WindowList&
Desktop::_Windows(int32 index)
{
	return fWorkspaces[index].Windows();
}


void
Desktop::_UpdateFloating(int32 previousWorkspace, int32 nextWorkspace)
{
	if (previousWorkspace == -1)
		previousWorkspace = fCurrentWorkspace;
	if (nextWorkspace == -1)
		nextWorkspace = previousWorkspace;

	for (WindowLayer* floating = fSubsetWindows.FirstWindow(); floating != NULL;
			floating = floating->NextWindow(kSubsetList)) {
		// we only care about app/subset floating windows
		if (floating->Feel() != B_FLOATING_SUBSET_WINDOW_FEEL
			&& floating->Feel() != B_FLOATING_APP_WINDOW_FEEL)
			continue;

		if (fFront != NULL && fFront->IsNormal() && floating->HasInSubset(fFront)) {
			// is now visible
			if (_Windows(previousWorkspace).HasWindow(floating)
				&& previousWorkspace != nextWorkspace) {
				// but no longer on the previous workspace
				_Windows(previousWorkspace).RemoveWindow(floating);
				floating->SetCurrentWorkspace(-1);
			}
			if (!_Windows(nextWorkspace).HasWindow(floating)) {
				// but wasn't before
				_Windows(nextWorkspace).AddWindow(floating,
					floating->Frontmost(_Windows(nextWorkspace).FirstWindow(), nextWorkspace));
				floating->SetCurrentWorkspace(nextWorkspace);
				_ShowWindow(floating);

				// TODO:
				// put the floating last in the floating window list to preserve
				// the on screen window order
			}
		} else if (_Windows(previousWorkspace).HasWindow(floating)) {
			// was visible, but is no longer
			_Windows(previousWorkspace).RemoveWindow(floating);
			floating->SetCurrentWorkspace(-1);
			_HideWindow(floating);
		}
	}
}


/*!
	Search the visible windows for a valid back window
	(only desktop windows can't be back windows)
*/
void
Desktop::_UpdateBack()
{
	fBack = NULL;

	for (WindowLayer* window = _CurrentWindows().FirstWindow();
			window != NULL; window = window->NextWindow(fCurrentWorkspace)) {
		if (window->IsHidden() || window->Feel() == kDesktopWindowFeel)
			continue;

		fBack = window;
		break;
	}
}


/*!
	Search the visible windows for a valid front window
	(only normal and modal windows can be front windows)

	The only place where you don't want to update floating windows is
	during a workspace change - because then you'll call _UpdateFloating()
	yourself.
*/
void
Desktop::_UpdateFront(bool updateFloating)
{
	fFront = NULL;

	for (WindowLayer* window = _CurrentWindows().LastWindow();
			window != NULL; window = window->PreviousWindow(fCurrentWorkspace)) {
		if (window->IsHidden() || window->IsFloating() || !window->SupportsFront())
			continue;

		fFront = window;
		break;
	}

	if (updateFloating)
		_UpdateFloating();
}


void
Desktop::_UpdateFronts(bool updateFloating)
{
	_UpdateBack();
	_UpdateFront(updateFloating);
}


bool
Desktop::_WindowHasModal(WindowLayer* window)
{
	if (window == NULL || window->IsFloating())
		return false;

	for (WindowLayer* modal = fSubsetWindows.FirstWindow(); modal != NULL;
			modal = modal->NextWindow(kSubsetList)) {
		// only visible modal windows count
		if (!modal->IsModal() || modal->IsHidden())
			continue;

		if (modal->HasInSubset(window))
			return true;
	}

	return false;
}


void
Desktop::_WindowChanged(WindowLayer* window)
{
	if (fWorkspacesLayer == NULL)
		return;

	fWorkspacesLayer->WindowChanged(window);
}


/*!
	\brief Sends a fake B_MOUSE_MOVED event to the window under the mouse,
		and also updates the current view under the mouse.

	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(WindowLayer* window)
{
	BPoint where;
	int32 buttons;
	EventDispatcher().GetMouse(where, buttons);

	int32 viewToken = B_NULL_TOKEN;
	BMessenger target;

	LockAllWindows();

	if (window == NULL)
		window = MouseEventWindow();
	if (window == NULL)
		window = WindowAt(where);

	if (window != NULL) {
		BMessage message;
		window->MouseMoved(&message, where, &viewToken, true);
	}

	if (viewToken != B_NULL_TOKEN)
		SetViewUnderMouse(window, viewToken);
	else {
		SetViewUnderMouse(NULL, B_NULL_TOKEN);
		SetCursor(NULL);
	}

	UnlockAllWindows();

	if (viewToken != B_NULL_TOKEN)
		EventDispatcher().SendFakeMouseMoved(target, viewToken);
}


void
Desktop::SetFocusWindow(WindowLayer* focus)
{
	if (!LockAllWindows())
		return;

	bool hasModal = _WindowHasModal(focus);

	// TODO: test for FFM and B_LOCK_WINDOW_FOCUS

	if (focus == fFocus && focus != NULL && !focus->IsHidden()
		&& (focus->Flags() & B_AVOID_FOCUS) == 0 && !hasModal) {
		// the window that is supposed to get focus already has focus
		UnlockAllWindows();
		return;
	}

	if (focus == NULL || hasModal) {
		focus = FrontWindow();
		if (focus == NULL) {
			// there might be no front window in case of only a single
			// window with B_FLOATING_ALL_WINDOW_FEEL
			focus = _CurrentWindows().LastWindow();
		}
	}

	// make sure no window is chosen that doesn't want focus or cannot have it
	while (focus != NULL
		&& ((focus->Flags() & B_AVOID_FOCUS) != 0
			|| _WindowHasModal(focus)
			|| focus->IsHidden())) {
		focus = focus->PreviousWindow(fCurrentWorkspace);
	}

	if (fFocus == focus) {
		// turns out the window that is supposed to get focus now already has it
		UnlockAllWindows();
		return;
	}

	ServerApp* oldActiveApp = NULL;
	ServerApp* newActiveApp = NULL;

	if (fFocus != NULL) {
		fFocus->SetFocus(false);
		oldActiveApp = fFocus->ServerWindow()->App();
	}

	fFocus = focus;

	if (fFocus != NULL) {
		fFocus->SetFocus(true);
		newActiveApp = fFocus->ServerWindow()->App();
	}

	UnlockAllWindows();

	// change the "active" app if appropriate
	if (oldActiveApp != newActiveApp) {
		if (oldActiveApp) {
			oldActiveApp->Activate(false);
		}

		if (newActiveApp) {
			newActiveApp->Activate(true);
		} else {
			// make sure the cursor is visible
			HWInterface()->SetCursorVisible(true);
		}
	}
}


void
Desktop::_BringWindowsToFront(WindowList& windows, int32 list,
	bool wereVisible)
{
	// we don't need to redraw what is currently
	// visible of the window
	BRegion clean;

	for (WindowLayer* window = windows.FirstWindow(); window != NULL;
			window = window->NextWindow(list)) {
		if (wereVisible)
			clean.Include(&window->VisibleRegion());

		_CurrentWindows().AddWindow(window,
			window->Frontmost(_CurrentWindows().FirstWindow(),
				fCurrentWorkspace));

		_WindowChanged(window);
	}

	BRegion dummy;
	_RebuildClippingForAllWindows(dummy);

	// redraw what became visible of the window(s)

	BRegion dirty;
	for (WindowLayer* window = windows.FirstWindow(); window != NULL;
			window = window->NextWindow(list)) {
		dirty.Include(&window->VisibleRegion());
	}

	dirty.Exclude(&clean);
	MarkDirty(dirty);

	_UpdateFront();

	if (windows.FirstWindow() == fBack || fBack == NULL)
		_UpdateBack();
}


/*!
	\brief Tries to move the specified window to the front of the screen,
		and make it the focus window.

	If there are any modal windows on this screen, it might not actually
	become the frontmost window, though, as modal windows stay in front
	of their subset.
*/
void
Desktop::ActivateWindow(WindowLayer* window)
{
	STRACE(("ActivateWindow(%p, %s)\n", window, window ? window->Title() : "<none>"));

	// TODO: handle this case correctly! (ie. honour B_NOT_ANCHORED_ON_ACTIVATE,
	//		B_NO_WORKSPACE_ACTIVATION, switch workspaces, ...)
	if (!window->InWorkspace(fCurrentWorkspace))
		return;

	if (window == NULL) {
		fBack = NULL;
		fFront = NULL;
		return;
	}

	// TODO: support B_NO_WORKSPACE_ACTIVATION
	// TODO: support B_NOT_ANCHORED_ON_ACTIVATE
	// TODO: take care about floating windows

	if (!LockAllWindows())
		return;

	if (window == FrontWindow()) {
		// see if there is a normal B_AVOID_FRONT window still in front of us
		WindowLayer* avoidsFront = window->NextWindow(fCurrentWorkspace);
		while (avoidsFront && avoidsFront->IsNormal()
			&& (avoidsFront->Flags() & B_AVOID_FRONT) == 0) {
			avoidsFront = avoidsFront->NextWindow(fCurrentWorkspace);
		}

		if (avoidsFront == NULL) {
			// we're already the frontmost window, we might just not have focus yet
			SetFocusWindow(window);

			UnlockAllWindows();
			return;
		}
	}

	// we don't need to redraw what is currently
	// visible of the window
	BRegion clean(window->VisibleRegion());
	WindowList windows(kWorkingList);

	WindowLayer* frontmost = window->Frontmost();

	_CurrentWindows().RemoveWindow(window);
	windows.AddWindow(window);

	if (frontmost != NULL && frontmost->IsModal()) {
		// all modal windows follow their subsets to the front
		// (ie. they are staying in front of them, but they are
		// not supposed to change their order because of that)

		WindowLayer* nextModal;
		for (WindowLayer* modal = frontmost; modal != NULL; modal = nextModal) {
			// get the next modal window
			nextModal = modal->NextWindow(fCurrentWorkspace);
			while (nextModal != NULL && !nextModal->IsModal()) {
				nextModal = nextModal->NextWindow(fCurrentWorkspace);
			}
			if (nextModal != NULL && !nextModal->HasInSubset(window))
				nextModal = NULL;

			_CurrentWindows().RemoveWindow(modal);
			windows.AddWindow(modal);
		}
	}

	_BringWindowsToFront(windows, kWorkingList, true);
	SetFocusWindow(window);

	UnlockAllWindows();
}


void
Desktop::SendWindowBehind(WindowLayer* window, WindowLayer* behindOf)
{
	if (window == BackWindow() || !LockAllWindows())
		return;

	// Is this a valid behindOf window?
	if (behindOf != NULL && window->HasInSubset(behindOf))
		behindOf = NULL;

	// what is currently visible of the window
	// might be dirty after the window is send to back
	BRegion dirty(window->VisibleRegion());

	// detach window and re-attach at desired position
	WindowLayer* backmost = window->Backmost(behindOf);

	_CurrentWindows().RemoveWindow(window);
	_CurrentWindows().AddWindow(window, backmost
		? backmost->NextWindow(fCurrentWorkspace) : BackWindow());

	BRegion dummy;
	_RebuildClippingForAllWindows(dummy);

	// mark everything dirty that is no longer visible
	BRegion clean(window->VisibleRegion());
	dirty.Exclude(&clean);
	MarkDirty(dirty);

	_UpdateFronts();
	SetFocusWindow(_CurrentWindows().LastWindow());
	_WindowChanged(window);

	UnlockAllWindows();
}


void
Desktop::ShowWindow(WindowLayer* window)
{
	if (!window->IsHidden())
		return;

	LockAllWindows();

	window->SetHidden(false);

	if (window->InWorkspace(fCurrentWorkspace)) {
		_ShowWindow(window, true);
		_UpdateSubsetWorkspaces(window);
		ActivateWindow(window);
	} else {
		// then we don't need to send the fake mouse event either
		UnlockAllWindows();
		return;
	}

	if (WorkspacesLayer* layer = dynamic_cast<WorkspacesLayer*>(window->TopLayer()))
		fWorkspacesLayer = layer;

	UnlockAllWindows();

	// If the mouse cursor is directly over the newly visible window,
	// we'll send a fake mouse moved message to the window, so that
	// it knows the mouse is over it.

	_SendFakeMouseMoved(window);
}


void
Desktop::HideWindow(WindowLayer* window)
{
	if (window->IsHidden())
		return;

	if (!LockAllWindows())
		return;

	window->SetHidden(true);
	if (fMouseEventWindow == window)
		fMouseEventWindow = NULL;

	if (window->InWorkspace(fCurrentWorkspace)) {
		_UpdateSubsetWorkspaces(window);
		_HideWindow(window);
		_UpdateFronts();

		if (FocusWindow() == window)
			SetFocusWindow(_CurrentWindows().LastWindow());
	}

	if (fWorkspacesLayer != NULL)
		fWorkspacesLayer->WindowRemoved(window);

	if (dynamic_cast<WorkspacesLayer*>(window->TopLayer()) != NULL)
		fWorkspacesLayer = NULL;

	UnlockAllWindows();

	if (window == fWindowUnderMouse)
		_SendFakeMouseMoved();
}


/*!
	Shows the window on the screen - it does this independently of the
	WindowLayer::IsHidden() state.
*/
void
Desktop::_ShowWindow(WindowLayer* window, bool affectsOtherWindows)
{
	BRegion background;
	_RebuildClippingForAllWindows(background);
	_SetBackground(background);
	_WindowChanged(window);

	BRegion dirty(window->VisibleRegion());

	if (!affectsOtherWindows) {
		// everything that is now visible in the
		// window needs a redraw, but other windows
		// are not affected, we can call ProcessDirtyRegion()
		// of the window, and don't have to use MarkDirty()
		window->ProcessDirtyRegion(dirty);
	} else
		MarkDirty(dirty);
}


/*!
	Hides the window from the screen - it does this independently of the
	WindowLayer::IsHidden() state.
*/
void
Desktop::_HideWindow(WindowLayer* window)
{
	// after rebuilding the clipping,
	// this window will not have a visible
	// region anymore, so we need to remember
	// it now
	// (actually that's not true, since
	// hidden windows are excluded from the
	// clipping calculation, but anyways)
	BRegion dirty(window->VisibleRegion());

	BRegion background;
	_RebuildClippingForAllWindows(background);
	_SetBackground(background);
	_WindowChanged(window);

	MarkDirty(dirty);
}


void
Desktop::MoveWindowBy(WindowLayer* window, float x, float y, int32 workspace)
{
	if (!LockAllWindows())
		return;

	if (workspace == -1)
		workspace = fCurrentWorkspace;

	if (!window->IsVisible() || workspace != fCurrentWorkspace) {
		if (workspace != fCurrentWorkspace) {
			// move the window on another workspace - this doesn't change it's
			// current position
			if (window->Anchor(workspace).position == kInvalidWindowPosition)
				window->Anchor(workspace).position = window->Frame().LeftTop();

			window->Anchor(workspace).position += BPoint(x, y);
			_WindowChanged(window);
		} else
			window->MoveBy(x, y);

		UnlockAllWindows();
		return;
	}

	// the dirty region starts with the visible area of the window being moved
	BRegion newDirtyRegion(window->VisibleRegion());

	// no more drawing for DirectWindows
	window->ServerWindow()->HandleDirectConnection(B_DIRECT_STOP);

	window->MoveBy(x, y);

	BRegion background;
	_RebuildClippingForAllWindows(background);

	// construct the region that is possible to be blitted
	// to move the contents of the window
	BRegion copyRegion(window->VisibleRegion());
	copyRegion.OffsetBy(-x, -y);
	copyRegion.IntersectWith(&newDirtyRegion);
		// newDirtyRegion == the windows old visible region

	// include the the new visible region of the window being
	// moved into the dirty region (for now)
	newDirtyRegion.Include(&window->VisibleRegion());

	GetDrawingEngine()->CopyRegion(&copyRegion, x, y);

	// allow DirectWindows to draw again after the visual
	// content is at the new location
	window->ServerWindow()->HandleDirectConnection(B_DIRECT_START | B_BUFFER_MOVED);

	// in the dirty region, exclude the parts that we
	// could move by blitting
	copyRegion.OffsetBy(x, y);
	newDirtyRegion.Exclude(&copyRegion);

	MarkDirty(newDirtyRegion);
	_SetBackground(background);
	_WindowChanged(window);

	UnlockAllWindows();
}


void
Desktop::ResizeWindowBy(WindowLayer* window, float x, float y)
{
	if (!LockAllWindows())
		return;

	if (!window->IsVisible()) {
		window->ResizeBy(x, y, NULL);
		UnlockAllWindows();
		return;
	}

	// the dirty region for the inside of the window is
	// constructed by the window itself in ResizeBy()
	BRegion newDirtyRegion;
	// track the dirty region outside the window in case
	// it is shrunk in "previouslyOccupiedRegion"
	BRegion previouslyOccupiedRegion(window->VisibleRegion());
	
	window->ResizeBy(x, y, &newDirtyRegion);

	BRegion background;
	_RebuildClippingForAllWindows(background);

	// we just care for the region outside the window
	previouslyOccupiedRegion.Exclude(&window->VisibleRegion());

	// make sure the window cannot mark stuff dirty outside
	// its visible region...
	newDirtyRegion.IntersectWith(&window->VisibleRegion());
	// ...because we do this outself
	newDirtyRegion.Include(&previouslyOccupiedRegion);

	MarkDirty(newDirtyRegion);
	_SetBackground(background);
	_WindowChanged(window);

	UnlockAllWindows();
}


/*!
	Updates the workspaces of all subset windows with regard to the
	specifed window.
*/
void
Desktop::_UpdateSubsetWorkspaces(WindowLayer* window)
{
	STRACE(("_UpdateSubsetWorkspaces(window %p, %s)\n", window, window->Title()));

	// if the window is hidden, the subset windows are up-to-date already
	if (!window->IsNormal() || window->IsHidden())
		return;

	for (WindowLayer* subset = fSubsetWindows.FirstWindow(); subset != NULL;
			subset = subset->NextWindow(kSubsetList)) {
		if (subset->Feel() == B_MODAL_ALL_WINDOW_FEEL
			|| subset->Feel() == B_FLOATING_ALL_WINDOW_FEEL) {
			// These windows are always visible on all workspaces,
			// no need to update them.
			continue;
		}

		if (subset->IsFloating()) {
			// Floating windows are inserted and removed to the current
			// workspace as the need arises - they are not handled here
			// but in _UpdateFront()
			continue;
		}

		if (subset->HasInSubset(window)) {
			// adopt the workspace change
			SetWindowWorkspaces(subset, subset->SubsetWorkspaces());
		}
	}
}


/*!
	\brief Adds or removes the window to or from the workspaces it's on.
*/
void
Desktop::_ChangeWindowWorkspaces(WindowLayer* window, uint32 oldWorkspaces,
	uint32 newWorkspaces)
{
	// apply changes to the workspaces' window lists

	LockAllWindows();

	for (int32 i = 0; i < kMaxWorkspaces; i++) {
		if (workspace_in_workspaces(i, oldWorkspaces)) {
			// window is on this workspace, is it anymore?
			if (!workspace_in_workspaces(i, newWorkspaces)) {
				_Windows(i).RemoveWindow(window);

				if (i == CurrentWorkspace()) {
					// remove its appearance from the current workspace
					window->SetCurrentWorkspace(-1);

					if (!window->IsHidden())
						_HideWindow(window);
				}
			}
		} else {
			// window was not on this workspace, is it now?
			if (workspace_in_workspaces(i, newWorkspaces)) {
				_Windows(i).AddWindow(window,
					window->Frontmost(_Windows(i).FirstWindow(), i));

				if (i == CurrentWorkspace()) {
					// make the window visible in current workspace
					window->SetCurrentWorkspace(fCurrentWorkspace);

					if (!window->IsHidden()) {
						// this only affects other windows if this windows has floating or
						// modal windows that need to be shown as well
						// TODO: take care of this
						_ShowWindow(window, FrontWindow() == window);
					}
				}
			}
		}
	}

	// take care about modals and floating windows
	_UpdateSubsetWorkspaces(window);

	UnlockAllWindows();
}


void
Desktop::SetWindowWorkspaces(WindowLayer* window, uint32 workspaces)
{
	LockAllWindows();

	if (window->IsNormal() && workspaces == B_CURRENT_WORKSPACE)
		workspaces = workspace_to_workspaces(CurrentWorkspace());

	uint32 oldWorkspaces = window->Workspaces();

	window->WorkspacesChanged(oldWorkspaces, workspaces);
	_ChangeWindowWorkspaces(window, oldWorkspaces, workspaces);

	UnlockAllWindows();
}


/*!	\brief Adds the window to the desktop.
	At this point, the window is still hidden and must be shown explicetly
	via ShowWindow().
*/
void
Desktop::AddWindow(WindowLayer *window)
{
	LockAllWindows();

	fAllWindows.AddWindow(window);
	if (!window->IsNormal())
		fSubsetWindows.AddWindow(window);

	if (window->IsNormal()) {
		if (window->Workspaces() == B_CURRENT_WORKSPACE)
			window->SetWorkspaces(workspace_to_workspaces(CurrentWorkspace()));
	} else {
		// subset windows are visible on all workspaces their subset is on
		window->SetWorkspaces(window->SubsetWorkspaces());
	}

	_ChangeWindowWorkspaces(window, 0, window->Workspaces());
	UnlockAllWindows();
}


void
Desktop::RemoveWindow(WindowLayer *window)
{
	LockAllWindows();

	if (!window->IsHidden())
		HideWindow(window);

	fAllWindows.RemoveWindow(window);
	if (!window->IsNormal())
		fSubsetWindows.RemoveWindow(window);

	_ChangeWindowWorkspaces(window, window->Workspaces(), 0);
	UnlockAllWindows();

	// make sure this window won't get any events anymore

	EventDispatcher().RemoveTarget(window->EventTarget());
}


bool
Desktop::AddWindowToSubset(WindowLayer* subset, WindowLayer* window)
{
	if (!subset->AddToSubset(window))
		return false;

	_ChangeWindowWorkspaces(subset, subset->Workspaces(), subset->SubsetWorkspaces());
	return true;
}


void
Desktop::RemoveWindowFromSubset(WindowLayer* subset, WindowLayer* window)
{
	subset->RemoveFromSubset(window);
	_ChangeWindowWorkspaces(subset, subset->Workspaces(), subset->SubsetWorkspaces());
}


void
Desktop::SetWindowLook(WindowLayer *window, window_look newLook)
{
	if (window->Look() == newLook)
		return;

	if (!LockAllWindows())
		return;

	BRegion dirty;
	window->SetLook(newLook, &dirty);
		// TODO: test what happens when the window
		// finds out it needs to resize itself...

	BRegion stillAvailableOnScreen;
	_RebuildClippingForAllWindows(stillAvailableOnScreen);
	_SetBackground(stillAvailableOnScreen);
	_WindowChanged(window);

	_TriggerWindowRedrawing(dirty);

	UnlockAllWindows();
}


void
Desktop::SetWindowFeel(WindowLayer *window, window_feel newFeel)
{
	if (window->Feel() == newFeel)
		return;

	LockAllWindows();

	bool wasNormal = window->IsNormal();

	window->SetFeel(newFeel);

	// move the window out of or into the subset window list as needed
	if (window->IsNormal() && !wasNormal)
		fSubsetWindows.RemoveWindow(window);
	else if (!window->IsNormal() && wasNormal)
		fSubsetWindows.AddWindow(window);

	// A normal window that was once a floating or modal window will
	// adopt the window's current workspaces

	if (!window->IsNormal())
		_ChangeWindowWorkspaces(window, window->Workspaces(), window->SubsetWorkspaces());

	// make sure the window has the correct position in the window lists
	//	(ie. all floating windows have to be on the top, ...)

	for (int32 i = 0; i < kMaxWorkspaces; i++) {
		if (!workspace_in_workspaces(i, window->Workspaces()))
			continue;

		WindowLayer* frontmost = window->Frontmost(_Windows(i).FirstWindow(), i);
		if (frontmost == NULL)
			continue;

		// check if the frontmost window is really in front of it

		WindowLayer* next = window->NextWindow(i);
		while (next != NULL) {
			if (next == frontmost)
				break;

			next = next->NextWindow(i);
		}

		if (next == NULL) {
			// need to reinsert window behind its frontmost window
			_Windows(i).RemoveWindow(window);
			_Windows(i).AddWindow(window, frontmost);
		}
	}

	_UpdateFronts();

	if (window == FocusWindow() && !window->IsVisible())
		SetFocusWindow(_CurrentWindows().LastWindow());

	UnlockAllWindows();
}


void
Desktop::SetWindowFlags(WindowLayer *window, uint32 newFlags)
{
	if (window->Flags() == newFlags)
		return;

	if (!LockAllWindows())
		return;

	BRegion dirty;
	window->SetFlags(newFlags, &dirty);
		// TODO: test what happens when the window
		// finds out it needs to resize itself...

	BRegion stillAvailableOnScreen;
	_RebuildClippingForAllWindows(stillAvailableOnScreen);
	_SetBackground(stillAvailableOnScreen);
	_WindowChanged(window);

	_TriggerWindowRedrawing(dirty);

	UnlockAllWindows();
}


void
Desktop::SetWindowTitle(WindowLayer *window, const char* title)
{
	if (!LockAllWindows())
		return;

	BRegion dirty;
	window->SetTitle(title, dirty);

	if (window->IsVisible() && dirty.CountRects() > 0) {
		BRegion stillAvailableOnScreen;
		_RebuildClippingForAllWindows(stillAvailableOnScreen);
		_SetBackground(stillAvailableOnScreen);
	
		_TriggerWindowRedrawing(dirty);
	}

	UnlockAllWindows();
}


/*!
	Returns the window under the mouse cursor.
	You need to have acquired the All Windows lock when calling this method.
*/
WindowLayer*
Desktop::WindowAt(BPoint where)
{
	for (WindowLayer* window = _CurrentWindows().LastWindow(); window;
			window = window->PreviousWindow(fCurrentWorkspace)) {
		if (window->IsVisible() && window->VisibleRegion().Contains(where))
			return window;
	}

	return NULL;
}


void
Desktop::SetMouseEventWindow(WindowLayer* window)
{
	fMouseEventWindow = window;
}


void
Desktop::SetViewUnderMouse(const WindowLayer* window, int32 viewToken)
{
	fWindowUnderMouse = window;
	fViewUnderMouse = viewToken;
}


int32
Desktop::ViewUnderMouse(const WindowLayer* window)
{
	if (fWindowUnderMouse == window)
		return fViewUnderMouse;

	return B_NULL_TOKEN;
}


WindowLayer *
Desktop::FindWindowLayerByClientToken(int32 token, team_id teamID)
{
	LockSingleWindow();

	for (WindowLayer *window = fAllWindows.FirstWindow(); window != NULL;
			window = window->NextWindow(kAllWindowList)) {
		if (window->ServerWindow()->ClientToken() == token
			&& window->ServerWindow()->ClientTeam() == teamID) {
			UnlockSingleWindow();
			return window;
		}
	}

	UnlockSingleWindow();
	return NULL;
}


void
Desktop::MinimizeApplication(team_id team)
{
	BAutolock locker(fWindowLock);

	// Just minimize all windows of that application

	for (WindowLayer *window = fAllWindows.FirstWindow(); window != NULL;
			window = window->NextWindow(kAllWindowList)) {
		if (window->ServerWindow()->ClientTeam() != team)
			continue;

		window->ServerWindow()->NotifyMinimize(true);
	}
}


void
Desktop::BringApplicationToFront(team_id team)
{
	BAutolock locker(fWindowLock);

	// TODO: for now, just maximize all windows of that application

	for (WindowLayer *window = fAllWindows.FirstWindow(); window != NULL;
			window = window->NextWindow(kAllWindowList)) {
		if (window->ServerWindow()->ClientTeam() != team)
			continue;

		window->ServerWindow()->NotifyMinimize(false);
	}
}


void
Desktop::WindowAction(int32 windowToken, int32 action)
{
	if (action != B_MINIMIZE_WINDOW && action != B_BRING_TO_FRONT)
		return;

	LockAllWindows();

	::ServerWindow* serverWindow;
	if (BPrivate::gDefaultTokens.GetToken(windowToken,
			B_SERVER_TOKEN, (void**)&serverWindow) != B_OK) {
		UnlockAllWindows();
		return;
	}

	if (action == B_BRING_TO_FRONT
		&& !serverWindow->Window()->IsMinimized()) {
		// the window is visible, we just need to make it the front window
		ActivateWindow(serverWindow->Window());
	} else
		serverWindow->NotifyMinimize(action == B_MINIMIZE_WINDOW);

	UnlockAllWindows();
}


void
Desktop::WriteWindowList(team_id team, BPrivate::LinkSender& sender)
{
	BAutolock locker(fWindowLock);

	// compute the number of windows

	int32 count = 0;

	for (WindowLayer *window = fAllWindows.FirstWindow(); window != NULL;
			window = window->NextWindow(kAllWindowList)) {
		if (team < B_OK || window->ServerWindow()->ClientTeam() == team)
			count++;
	}

	// write list

	sender.StartMessage(B_OK);
	sender.Attach<int32>(count);

	for (WindowLayer *window = fAllWindows.FirstWindow(); window != NULL;
			window = window->NextWindow(kAllWindowList)) {
		if (team >= B_OK && window->ServerWindow()->ClientTeam() != team)
			continue;

		sender.Attach<int32>(window->ServerWindow()->ServerToken());
	}

	sender.Flush();
}


void
Desktop::WriteWindowInfo(int32 serverToken, BPrivate::LinkSender& sender)
{
	BAutolock locker(fWindowLock);
	BAutolock tokenLocker(BPrivate::gDefaultTokens);

	::ServerWindow* window;
	if (BPrivate::gDefaultTokens.GetToken(serverToken,
			B_SERVER_TOKEN, (void**)&window) != B_OK) {
		sender.StartMessage(B_ENTRY_NOT_FOUND);
		sender.Flush();
		return;
	}

	window_info info;
	window->GetInfo(info);

	int32 length = window->Title() ? strlen(window->Title()) : 0;

	sender.StartMessage(B_OK);
	sender.Attach<int32>(sizeof(window_info) + length + 1);
	sender.Attach(&info, sizeof(window_info));
	if (length > 0)
		sender.Attach(window->Title(), length + 1);
	else
		sender.Attach<char>('\0');
	sender.Flush();
}


void
Desktop::MarkDirty(BRegion& region)
{
	if (region.CountRects() == 0)
		return;

	if (LockAllWindows()) {
		// send redraw messages to all windows intersecting the dirty region
		_TriggerWindowRedrawing(region);

		UnlockAllWindows();
	}
}


void
Desktop::_RebuildClippingForAllWindows(BRegion& stillAvailableOnScreen)
{
	// the available region on screen starts with the entire screen area
	// each window on the screen will take a portion from that area

	// figure out what the entire screen area is
	stillAvailableOnScreen = fScreenRegion;

	// set clipping of each window
	for (WindowLayer* window = _CurrentWindows().LastWindow(); window != NULL;
			window = window->PreviousWindow(fCurrentWorkspace)) {
		if (!window->IsHidden()) {
			window->SetClipping(&stillAvailableOnScreen);
			// that windows region is not available on screen anymore
			stillAvailableOnScreen.Exclude(&window->VisibleRegion());
		}
	}
}


void
Desktop::_TriggerWindowRedrawing(BRegion& newDirtyRegion)
{
	// send redraw messages to all windows intersecting the dirty region
	for (WindowLayer* window = _CurrentWindows().LastWindow(); window != NULL;
			window = window->PreviousWindow(fCurrentWorkspace)) {
		if (!window->IsHidden()
			&& newDirtyRegion.Intersects(window->VisibleRegion().Frame()))
			window->ProcessDirtyRegion(newDirtyRegion);
	}
}


void
Desktop::_SetBackground(BRegion& background)
{
	// NOTE: the drawing operation is caried out
	// in the clipping region rebuild, but it is
	// ok actually, because it also avoids trails on
	// moving windows

	// remember the region not covered by any windows
	// and redraw the dirty background 
	BRegion dirtyBackground(background);
	dirtyBackground.Exclude(&fBackgroundRegion);
	dirtyBackground.IntersectWith(&background);
	fBackgroundRegion = background;
	if (dirtyBackground.Frame().IsValid()) {
		if (GetDrawingEngine()->Lock()) {
			GetDrawingEngine()->ConstrainClippingRegion(NULL);
			GetDrawingEngine()->FillRegion(dirtyBackground,
				fWorkspaces[fCurrentWorkspace].Color());

			GetDrawingEngine()->Unlock();
		}
	}
}