Merge branch 'master' of gitlab.science.ru.nl:clean-and-itasks/iTasks-SDK into onDestroy-io

Libraries/iTasks/Engine.dcl

@@ -58,21 +58,22 @@ instance Startable (a,b) | Startable a & Startable b
 
 
 :: EngineOptions =
-	{ appName 		:: String
-	, appPath		:: FilePath // Location of the application's executable
+	{ appName       :: String
+	, appPath       :: FilePath // Location of the application's executable
 	, appVersion    :: String
-	, serverPort	:: Int
-    , serverUrl     :: String
+	, serverPort    :: Int
+	, serverUrl     :: String
 	, keepaliveTime :: Timespec
-    , sessionTime   :: Timespec
-    , persistTasks  :: Bool
+	, sessionTime   :: Timespec
+	, persistTasks  :: Bool
 	, autoLayout    :: Bool
+	, maxEvents     :: Int
 	, timeout       :: Maybe Int // The timeout
 	, distributed   :: Bool
-	, sdsPort		:: Int
-	, webDirPath 	:: FilePath  // Location of public files that are served by the iTask webserver
-	, storeDirPath 	:: FilePath  // Location of the application's persistent data files 
-	, tempDirPath 	:: FilePath  // Location for temporary files used in tasks
+	, sdsPort       :: Int
+	, webDirPath    :: FilePath  // Location of public files that are served by the iTask webserver
+	, storeDirPath  :: FilePath  // Location of the application's persistent data files 
+	, tempDirPath   :: FilePath  // Location for temporary files used in tasks
 	, saplDirPath   :: FilePath  // Location of the application's sapl files (client-side code)
 	}
 

Libraries/iTasks/Engine.icl

 implementation module iTasks.Engine
 
-import StdMisc, StdArray, StdList, StdOrdList, StdTuple, StdChar, StdFile, StdBool, StdEnum
+import Data.Func
+import Data.Functor
+import Data.Queue
+import Internet.HTTP
+import StdEnv
+import System.CommandLine
+import System.Directory
+import System.File
+import System.FilePath
+import System.GetOpt
+import System.OS
+import Text
+import iTasks.Internal.Distributed.Symbols
+import iTasks.Internal.EngineTasks
+import iTasks.Internal.IWorld
+import iTasks.Internal.SDS
+import iTasks.Internal.SDSService
+import iTasks.Internal.TaskServer
+import iTasks.Internal.TaskStore
+import iTasks.Internal.Util
+import iTasks.SDS.Sources.System
 import iTasks.WF.Combinators.Common
+import iTasks.WF.Definition
+import iTasks.WF.Tasks.SDS
 import iTasks.WF.Tasks.System
 
-import StdInt, StdChar, StdString
-from StdFunc import o, seqList, ::St, const, id
-
-import tcp
-import Internet.HTTP, System.GetOpt, Data.Func, Data.Functor
-
-from Data.Map import :: Map
-from Data.Queue import :: Queue(..)
-from Data.Set import :: Set, newSet
-
 import qualified Data.Map as DM
-from System.OS import IF_POSIX_OR_WINDOWS, OS_NEWLINE, IF_WINDOWS
-
-import Data.List, Data.Error, Data.Func, Data.Tuple, Math.Random, Text
-import System.Time, System.CommandLine, System.Environment, System.OSError, System.File, System.FilePath, System.Directory
-
-import iTasks.Internal.Util, iTasks.Internal.HtmlUtil
-import iTasks.Internal.IWorld, iTasks.Internal.WebService, iTasks.Internal.SDSService
-import qualified iTasks.Internal.SDS as SDS
-import iTasks.UI.Layout, iTasks.UI.Layout.Default
 
-from iTasks.WF.Tasks.SDS import get
-from iTasks.WF.Combinators.Tune import class tune(..), instance tune ApplyLayout Task, :: ApplyLayout(..)
-from iTasks.SDS.Combinators.Common import sdsFocus
-from iTasks.SDS.Sources.System import applicationOptions
-
-import iTasks.Internal.IWorld, iTasks.Internal.TaskEval, iTasks.Internal.TaskStore
-import iTasks.Internal.Util
-import iTasks.Internal.TaskServer
-import iTasks.Internal.EngineTasks
-import iTasks.Internal.Distributed.Symbols
-
-from Sapl.Linker.LazyLinker import generateLoaderState, :: LoaderStateExt
-from Sapl.Linker.SaplLinkerShared import :: SkipSet
-from Sapl.Target.Flavour import :: Flavour, toFlavour
+from TCPIP import :: Timeout
+from StdFunc import :: St, seqList
 
 MAX_EVENTS 		        :== 5
 
@@ -49,23 +40,30 @@ doTasks startable world = doTasksWithOptions defaultEngineCLIOptions startable w
 
 doTasksWithOptions :: ([String] EngineOptions -> MaybeError [String] EngineOptions) a !*World -> *World | Startable a
 doTasksWithOptions initFun startable world
-	# (cli,world)			= getCommandLine world
-	# (options,world)       = defaultEngineOptions world
-	# mbOptions             = initFun cli options
-	| mbOptions =:(Error _) = show (fromError mbOptions) world
-	# options               = fromOk mbOptions
-	# iworld				= createIWorld options world
-	# (res,iworld) 			= initJSCompilerState iworld
-	| res =:(Error _) 		= show ["Fatal error: " +++ fromError res] (destroyIWorld iworld)
-	# (symbolsResult, iworld) = initSymbolsShare options.distributed options.appName iworld
+	# (cli,world)                = getCommandLine world
+	# (options,world)            = defaultEngineOptions world
+	# mbOptions                  = initFun cli options
+	| mbOptions =:(Error _)      = show (fromError mbOptions) world
+	# options                    = fromOk mbOptions
+	# iworld                     = createIWorld options world
+	# (res,iworld)               = initJSCompilerState iworld
+	| res =:(Error _)            = show ["Fatal error: " +++ fromError res] (destroyIWorld iworld)
+	# (symbolsResult, iworld)    = initSymbolsShare options.distributed options.appName iworld
 	| symbolsResult =: (Error _) = show ["Error reading symbols while required: " +++ fromError symbolsResult] (destroyIWorld iworld)
-	# iworld				= serve (startupTasks options) (tcpTasks options.serverPort options.keepaliveTime)
-	                                engineTasks (timeout options.timeout) iworld
+	# iworld                     = serve (startupTasks options) (tcpTasks options.serverPort options.keepaliveTime) (timeout options.timeout) iworld
 	= destroyIWorld iworld
 where
     webTasks = [t \\ WebTask t <- toStartable startable]
-	startupTasks {distributed, sdsPort} = (if distributed [case onStartup (sdsServiceTask sdsPort) of StartupTask t = t;] []) ++ [t \\ StartupTask t <- toStartable startable]
-	hasWebTasks = not (webTasks =: [])
+	startupTasks {distributed, sdsPort}
+		//If distributed, start sds service task
+		=  (if distributed [startTask (sdsServiceTask sdsPort)] [])
+		++ [startTask flushWritesWhenIdle
+		//If there no webtasks, stop when stable, otherwise cleanup old sessions
+		   ,startTask if (webTasks =: []) stopOnStable removeOutdatedSessions
+		//Start all startup tasks
+		   :[t \\ StartupTask t <- toStartable startable]]
+
+	startTask t = {StartupTask|attributes=defaultValue,task=TaskWrapper t}
 
 	initSymbolsShare False _ iworld = (Ok (), iworld)
 	initSymbolsShare True appName iworld = case storeSymbols (IF_WINDOWS (appName +++ ".exe") appName) iworld of
@@ -78,16 +76,6 @@ where
 		| otherwise
 			= [(serverPort,httpServer serverPort keepaliveTime (engineWebService webTasks) taskOutput)]
 
-	engineTasks =
- 		[BackgroundTask updateClock,
- 		 BackgroundTask (processEvents MAX_EVENTS)
-		:if (webTasks =: [])
-			[BackgroundTask stopOnStable]
-			[BackgroundTask removeOutdatedSessions
-		 	,BackgroundTask flushWritesWhenIdle
-			]
-		]
-
 	// The iTasks engine consist of a set of HTTP Web services
 	engineWebService :: [WebTask] -> [WebService (Map InstanceNo TaskOutput) (Map InstanceNo TaskOutput)]
 	engineWebService webtasks =
@@ -114,7 +102,7 @@ defaultEngineCLIOptions [argv0:argv] defaults
 where
 	opts :: [OptDescr ((Maybe EngineOptions) -> Maybe EngineOptions)]
 	opts =
-		[ Option ['?'] ["help"] (NoArg $ const Nothing)
+		[ Option ['?'] ["help"] (NoArg (\_->Nothing))
 			"Display this message"
 		, Option ['p'] ["port"] (ReqArg (\p->fmap \o->{o & serverPort=toInt p}) "PORT")
 			("Specify the HTTP port (default: " +++ toString defaults.serverPort +++ ")")
@@ -122,6 +110,8 @@ where
 			"Specify the timeout in ms (default: 500)\nIf not given, use an indefinite timeout."
 		, Option [] ["keepalive"] (ReqArg (\p->fmap \o->{o & keepaliveTime={tv_sec=toInt p,tv_nsec=0}}) "SECONDS")
 			"Specify the keepalive time in seconds (default: 300)"
+		, Option [] ["maxevents"] (ReqArg (\p->fmap \o->{o & maxEvents=toInt p}) "NUM")
+			"Specify the maximum number of events to process per loop (default: 5)"
 		, Option [] ["sessiontime"] (ReqArg (\p->fmap \o->{o & sessionTime={tv_sec=toInt p,tv_nsec=0}}) "SECONDS")
 			"Specify the expiry time for a session in seconds (default: 60)"
 		, Option [] ["autolayout"] (NoArg (fmap \o->{o & autoLayout=True}))
@@ -208,22 +198,23 @@ defaultEngineOptions world
 	# appDir             = takeDirectory appPath
 	# appName            = (dropExtension o dropDirectory) appPath
 	# options =
-		{ appName			= appName
-		, appPath			= appPath
-		, appVersion        = appVersion
-		, serverPort		= IF_POSIX_OR_WINDOWS 8080 80
-        , serverUrl         = "http://localhost/"
-		, keepaliveTime     = {tv_sec=300,tv_nsec=0} // 5 minutes
-		, sessionTime       = {tv_sec=60,tv_nsec=0}  // 1 minute, (the client pings every 10 seconds by default)
-        , persistTasks      = False
-		, autoLayout        = True
-		, distributed       = False
-		, sdsPort			= 9090
-		, timeout			= Just 500
-		, webDirPath 		= appDir </> appName +++ "-www"
-		, storeDirPath      = appDir </> appName +++ "-data" </> "stores"
-		, tempDirPath       = appDir </> appName +++ "-data" </> "tmp"
-		, saplDirPath 	    = appDir </> appName +++ "-sapl"
+		{ appName        = appName
+		, appPath        = appPath
+		, appVersion     = appVersion
+		, serverPort     = IF_POSIX_OR_WINDOWS 8080 80
+		, serverUrl      = "http://localhost/"
+		, keepaliveTime  = {tv_sec=300,tv_nsec=0} // 5 minutes
+		, sessionTime    = {tv_sec=60,tv_nsec=0}  // 1 minute, (the client pings every 10 seconds by default)
+		, persistTasks   = False
+		, autoLayout     = True
+		, distributed    = False
+		, maxEvents      = 5
+		, sdsPort        = 9090
+		, timeout        = Nothing//Just 500
+		, webDirPath     = appDir </> appName +++ "-www"
+		, storeDirPath   = appDir </> appName +++ "-data" </> "stores"
+		, tempDirPath    = appDir </> appName +++ "-data" </> "tmp"
+		, saplDirPath    = appDir </> appName +++ "-sapl"
 		}
 	= (options,world)
 
@@ -256,3 +247,29 @@ determineAppVersion appPath world
 	# version           = strfTime "%Y%m%d-%H%M%S" tm
 	= (version,world)
 
+timeout :: !(Maybe Timeout) !*IWorld -> (!Maybe Timeout,!*IWorld)
+timeout mt iworld = case read taskEvents EmptyContext iworld of
+	//No events
+	(Ok (ReadingDone (Queue [] [])),iworld=:{sdsNotifyRequests,world})
+		# (ts, world) = nsTime world
+		= ( minListBy lesser [mt:flatten (map (getTimeoutFromClock ts) ('DM'.elems sdsNotifyRequests))]
+		  , {iworld & world = world})
+	(Ok (ReadingDone (Queue _ _)), iworld)               = (Just 0,iworld)   //There are still events, don't wait
+	(Error _,iworld)            = (Just 500,iworld) //Keep retrying, but not too fast
+where
+	lesser (Just x) (Just y) = x < y
+	lesser (Just _) Nothing = True
+	lesser Nothing Nothing = False
+
+	getTimeoutFromClock :: Timespec (Map SDSNotifyRequest Timespec) -> [Maybe Timeout]
+	getTimeoutFromClock now requests = map getTimeoutFromClock` ('DM'.toList requests)
+	where
+		getTimeoutFromClock` :: (!SDSNotifyRequest, !Timespec) -> Maybe Timeout
+		getTimeoutFromClock` (snr=:{cmpParam=(ts :: ClockParameter Timespec)}, reqTimespec)
+			| startsWith "$IWorld:timespec$" snr.reqSDSId && ts.interval <> zero
+				# fire = iworldTimespecNextFire now reqTimespec ts
+				= Just (max 0 (toMs fire - toMs now))
+			= mt
+		getTimeoutFromClock` _ = mt
+
+	toMs x = x.tv_sec * 1000 + x.tv_nsec / 1000000

Libraries/iTasks/Extensions/Editors/DynamicEditor.dcl

+definition module iTasks.Extensions.Editors.DynamicEditors
+
+import iTasks
+
+:: DynamicEditor a =: DynamicEditor [DynamicEditorElement]
+// phantom type only needed for top level
+:: DynamicEditorValue a = DynamicEditorValue !DynamicConsId !DEVal | Undefined // TODO: Undefined can be removed once we have parametrised editors
+
+:: DEVal = DEApplication ![(!DynamicConsId, !DEVal)]
+         | DEJSONValue   !JSONNode
+
+derive class iTask DynamicEditorValue
+
+:: DynamicEditorElement = DynamicCons !DynamicCons | DynamicConsGroup !String ![DynamicCons]
+:: DynamicCons
+:: DynamicConsOption = HideIfOnlyChoice | UseAsDefault
+
+(<<@@@) infixl 2 :: !DynamicCons !DynamicConsOption -> DynamicCons
+(@@@>>) infixr 2 :: !DynamicConsOption !DynamicCons -> DynamicCons
+
+:: DynamicConsId :== String
+:: DynamicConsBuilder =     FunctionCons     !Dynamic
+                     | E.a: CustomEditorCons !(Editor a) & JSONEncode{|*|}, JSONDecode{|*|}, gText{|*|}, TC a
+                     |      ListCons         !Dynamic    //* must contain a value of type [a] -> b
+
+functionCons     :: !String !String !a          -> DynamicCons | TC a
+listCons         :: !String !String !([a] -> b) -> DynamicCons | TC a & TC b
+customEditorCons :: !String !String !(Editor a) -> DynamicCons | TC, JSONEncode{|*|}, JSONDecode{|*|}, gText{|*|} a
+// dynamic variants are required because this is the only way to use quantified type variables
+functionConsDyn :: !String !String !Dynamic -> DynamicCons
+listConsDyn     :: !String !String !Dynamic -> DynamicCons
+
+dynamicEditor :: !(DynamicEditor a) -> Editor (DynamicEditorValue a) | TC a
+parametrisedDynamicEditor
+	:: !(p -> DynamicEditor a) -> Editor (!p, !DynamicEditorValue a)
+	| TC a & gEq{|*|}, JSONEncode{|*|}, JSONDecode{|*|} p
+
+toValue              :: !(DynamicEditor a) !(DynamicEditorValue a) -> a | TC a
+dynEditorValToString :: !(DynamicEditor a) !(DynamicEditorValue a) -> String

Libraries/iTasks/Extensions/TextFile.dcl

 definition module iTasks.Extensions.TextFile
 
 import iTasks
-from System.FilePath import :: FilePath
+from System.FilePath            import :: FilePath
+from iTasks.Extensions.Document import :: Document
 
 /**
 * Import the content of  a text file on the server's filesystem.
@@ -15,6 +16,16 @@ from System.FilePath import :: FilePath
 */
 importTextFile		:: !FilePath -> Task String
 
+/**
+* Import the content of a text file document.
+*
+* @param Document: The document to import
+*
+* @return The imported content
+* @throws FileException
+*/
+importTextDocument :: !Document -> Task String
+
 /**
 * Export a string as text file to the server's filesystem.
 *

Libraries/iTasks/Extensions/TextFile.icl

@@ -9,6 +9,13 @@ importTextFile :: !FilePath -> Task String
 importTextFile filename = mkInstantTask eval
 where
 	eval taskId iworld = fileTaskRead taskId filename readAll iworld
+
+importTextDocument :: !Document -> Task String
+importTextDocument {Document|documentId} = mkInstantTask eval
+where
+	eval taskId iworld
+		# (filename,iworld) = documentLocation documentId iworld
+		= fileTaskRead taskId filename readAll iworld
 	
 exportTextFile :: !FilePath !String -> Task String
 exportTextFile filename content = mkInstantTask eval

Libraries/iTasks/Internal/Client/RunOnClient.icl

@@ -132,6 +132,7 @@ createClientIWorld serverURL currentInstance
 						, autoLayout = True
 						, timeout = Just 100
 						, distributed = False
+						, maxEvents = 5
 						, sdsPort = 9090
 	                    , webDirPath  = locundef "webDirectory"
 	                    , storeDirPath = locundef "dataDirectory"

Libraries/iTasks/Internal/EngineTasks.dcl

@@ -2,18 +2,10 @@ definition module iTasks.Internal.EngineTasks
 /**
 * This module defines the separate system tasks that the iTasks engine performs
 */
-from iTasks.Internal.IWorld import :: IWorld
-from iTasks.WF.Definition import :: TaskException
-from Data.Error import :: MaybeError
-from Data.Maybe import :: Maybe
-from TCPIP import :: Timeout
+from iTasks.WF.Definition import :: Task
 
-timeout :: !(Maybe Timeout) !*IWorld -> (!Maybe Timeout,!*IWorld)
+removeOutdatedSessions :: Task ()
 
-updateClock :: !*IWorld -> *(!MaybeError TaskException (), !*IWorld)
+flushWritesWhenIdle:: Task ()
 
-removeOutdatedSessions :: !*IWorld -> *(!MaybeError TaskException (), !*IWorld)
-
-flushWritesWhenIdle:: !*IWorld -> (!MaybeError TaskException (), !*IWorld)
-
-stopOnStable :: !*IWorld -> *(!MaybeError TaskException (), !*IWorld)
+stopOnStable :: Task ()

Libraries/iTasks/Internal/EngineTasks.icl

 implementation module iTasks.Internal.EngineTasks
 
-import StdBool, StdOverloaded, StdList, StdOrdList
-import qualified Data.Map as DM
-import qualified Data.Set as DS
-import Data.List
-import Data.Functor, Data.Func
+import Data.Error
+import Data.Queue
+import StdEnv
 import iTasks.Engine
 import iTasks.Internal.IWorld
-import iTasks.WF.Definition
-import iTasks.Internal.Util
-import iTasks.Internal.SDS
+import iTasks.Internal.TaskEval
+import iTasks.Internal.TaskServer
+import iTasks.Internal.TaskState
 import iTasks.Internal.TaskStore
-import iTasks.SDS.Definition
 import iTasks.SDS.Combinators.Common
+import iTasks.UI.Definition
+import iTasks.WF.Definition
 
-from iTasks.Extensions.DateTime import toDate, toTime, instance == Date, instance == Time
-from System.Time import time
-import Text.GenJSON
-
-from TCPIP import :: Timeout
-
-import Data.Queue
-import Text
+from Data.Map import newMap
 
-timeout :: !(Maybe Timeout) !*IWorld -> (!Maybe Timeout,!*IWorld)
-timeout mt iworld = case read taskEvents EmptyContext iworld of
-	//No events
-	(Ok (ReadingDone (Queue [] [])),iworld=:{sdsNotifyRequests,world})
-		# (ts, world) = nsTime world
-		= ( minListBy lesser [mt:flatten $ map (getTimeoutFromClock ts) $ 'DM'.elems sdsNotifyRequests]
-		  , {iworld & world = world})
-	(Ok (ReadingDone (Queue _ _)), iworld)               = (Just 0,iworld)   //There are still events, don't wait
-	(Error _,iworld)            = (Just 500,iworld) //Keep retrying, but not too fast
+everyTick :: (*IWorld -> *(!MaybeError TaskException (), !*IWorld)) -> Task ()
+everyTick f = Task eval
 where
-	lesser (Just x) (Just y) = x < y
-	lesser (Just _) Nothing = True
-	lesser Nothing Nothing = False
-
-	getTimeoutFromClock :: Timespec (Map SDSNotifyRequest Timespec) -> [Maybe Timeout]
-	getTimeoutFromClock now requests = getTimeoutFromClock` <$> 'DM'.toList requests
-	where
-		getTimeoutFromClock` :: (!SDSNotifyRequest, !Timespec) -> Maybe Timeout
-		getTimeoutFromClock` (snr=:{cmpParam=(ts :: ClockParameter Timespec)}, reqTimespec)
-			| startsWith "$IWorld:timespec$" snr.reqSDSId && ts.interval <> zero
-				# fire = iworldTimespecNextFire now reqTimespec ts
-				= Just (max 0 (toMs fire - toMs now))
-			= mt
-		getTimeoutFromClock` _ = mt
-
-	toMs x = x.tv_sec * 1000 + x.tv_nsec / 1000000
-
-updateClock :: !*IWorld -> *(!MaybeError TaskException (), !*IWorld)
-updateClock iworld=:{IWorld|clock,world}
-    //Determine current date and time
-	# (timespec,world) 	= nsTime world
-    # iworld = {iworld & world = world}
-    //Write SDS if necessary
-    # (mbe,iworld) = write timespec (sdsFocus {start=zero,interval=zero} iworldTimespec) EmptyContext iworld
-    = case mbe of
-    	(Error e ) -> (Error e, iworld)
-    	(_) -> (Ok (), iworld)
-
+	eval event evalOpts tree=:(TCInit taskId ts) iworld
+		# (merr, iworld) = f iworld
+		| isError merr = (ExceptionResult (fromError merr), iworld)
+		# (merr, iworld) = readRegister taskId tick iworld
+		| isError merr = (ExceptionResult (fromError merr), iworld)
+		= (ValueResult
+				NoValue
+				{TaskEvalInfo|lastEvent=ts,removedTasks=[],attributes=newMap}
+				NoChange
+				(TCInit taskId ts)
+			, iworld)
+	
 //When we run the built-in HTTP server we need to do active garbage collection of instances that were created for sessions
-removeOutdatedSessions :: !*IWorld -> *(!MaybeError TaskException (), !*IWorld)
-removeOutdatedSessions iworld=:{IWorld|options}
-    # (mbIndex,iworld) = read (sdsFocus {InstanceFilter|defaultValue & onlySession=Just True} filteredInstanceIndex) EmptyContext iworld
-    = case mbIndex of
-        Ok (ReadingDone index) = checkAll removeIfOutdated index iworld
-        Error e     			= (Error e, iworld)
+removeOutdatedSessions :: Task ()
+removeOutdatedSessions = everyTick \iworld=:{IWorld|options}->
+	case read (sdsFocus {InstanceFilter|defaultValue & onlySession=Just True} filteredInstanceIndex) EmptyContext iworld of
+		(Ok (ReadingDone index), iworld) = checkAll (removeIfOutdated options) index iworld
+		(Error e, iworld)                = (Error e, iworld)
 where
 	checkAll f [] iworld = (Ok (),iworld)
 	checkAll f [x:xs] iworld = case f x iworld of
 		(Ok (),iworld) = checkAll f xs iworld
 		(Error e,iworld) = (Error e,iworld)
 
-    removeIfOutdated (instanceNo,_,_,_) iworld=:{options={appVersion},clock=tNow}
+    removeIfOutdated options (instanceNo,_,_,_) iworld=:{options={appVersion},clock=tNow}
 		# (remove,iworld) = case read (sdsFocus instanceNo taskInstanceIO) EmptyContext iworld of
 			//If there is I/O information, we check that age first
 			(Ok (ReadingDone (Just (client,tInstance))),iworld) //No IO for too long, clean up
@@ -103,27 +71,23 @@ where
 				= (Error e,iworld)
 
 //When the event queue is empty, write deferred SDS's
-flushWritesWhenIdle:: !*IWorld -> (!MaybeError TaskException (), !*IWorld)
-flushWritesWhenIdle iworld = case read taskEvents EmptyContext iworld of
+flushWritesWhenIdle:: Task ()
+flushWritesWhenIdle = everyTick \iworld->case read taskEvents EmptyContext iworld of
 		(Error e,iworld)          = (Error e,iworld)
 		(Ok (ReadingDone (Queue [] [])),iworld) = flushDeferredSDSWrites iworld
 		(Ok _,iworld)             = (Ok (),iworld)
 
 //When we don't run the built-in HTTP server we don't want to loop forever so we stop the loop
 //once all tasks are stable
-stopOnStable :: !*IWorld -> *(!MaybeError TaskException (), !*IWorld)
-stopOnStable iworld=:{IWorld|shutdown}
-    # (mbIndex,iworld) = read (sdsFocus {InstanceFilter|defaultValue & includeProgress=True} filteredInstanceIndex) EmptyContext iworld
-	= case mbIndex of
-		Ok (ReadingDone index)
+stopOnStable :: Task ()
+stopOnStable = everyTick \iworld=:{IWorld|shutdown}->case read (sdsFocus {InstanceFilter|defaultValue & includeProgress=True} filteredInstanceIndex) EmptyContext iworld of
+		(Ok (ReadingDone index), iworld)
 			# shutdown = case shutdown of
 				Nothing = if (allStable index) (Just (if (exceptionOccurred index) 1 0)) Nothing
 				_       = shutdown
 			= (Ok (), {IWorld|iworld & shutdown = shutdown})
-		Error e  = (Error e, iworld)
+		(Error e, iworld)  = (Error e, iworld)
 where
 	allStable instances = all (\v -> v =: Stable || v =: (Exception _)) (values instances)
 	exceptionOccurred instances = any (\v -> v =: (Exception _)) (values instances)
 	values instances = [value \\ (_,_,Just {InstanceProgress|value},_) <- instances]
-
-

Libraries/iTasks/Internal/IWorld.dcl

@@ -12,7 +12,7 @@ from Text.GenJSON				            import :: JSONNode
 from iTasks.Engine                      import :: EngineOptions
 from iTasks.UI.Definition				import :: UI, :: UIType
 from iTasks.Internal.TaskState		import :: ParallelTaskState, :: TIMeta, :: DeferredJSON
-from iTasks.Internal.Task             import :: ConnectionTask, :: BackgroundTask
+from iTasks.Internal.Task             import :: ConnectionTask
 from iTasks.Internal.TaskEval         import :: TaskTime
 
 from iTasks.WF.Definition import :: TaskValue, :: Event, :: TaskId, :: InstanceNo, :: TaskNo, :: TaskException
@@ -78,7 +78,6 @@ CLEAN_HOME_VAR	:== "CLEAN_HOME"
 :: *IOTaskInstance
     = ListenerInstance        !ListenerInstanceOpts !*TCP_Listener
     | ConnectionInstance      !ConnectionInstanceOpts !*TCP_DuplexChannel
-    | BackgroundInstance      !BackgroundInstanceOpts !BackgroundTask
 
 :: ListenerInstanceOpts =
     { taskId                :: !TaskId          //Reference to the task that created the listener
@@ -96,12 +95,6 @@ CLEAN_HOME_VAR	:== "CLEAN_HOME"
 
 :: ConnectionId             :== Int
 
-:: BackgroundInstanceOpts =
-    { bgInstId              :: !BackgroundTaskId
-    }
-
-:: BackgroundTaskId         :== Int
-
 :: IOStates :== Map TaskId IOState
 :: IOState
     = IOActive      !(Map ConnectionId (!Dynamic,!Bool)) // Bool: stability

Libraries/iTasks/Internal/IWorld.icl

@@ -195,4 +195,4 @@ where
 		= (x, {IWorld | iworld & world=world})
 	appFiles appfun iworld=:{IWorld|world}
 		# world = appFiles appfun world
-		= {IWorld | iworld & world=world}
\ No newline at end of file
+		= {IWorld | iworld & world=world}

Libraries/iTasks/Internal/Task.dcl

@@ -37,9 +37,6 @@ derive gEq				Task
     , onDestroy     :: !(                    l   *IWorld -> *(!MaybeErrorString l,          ![String],        !*IWorld))
     }
 
-//Background computation tasks
-:: BackgroundTask = BackgroundTask !(*IWorld -> *(!MaybeError TaskException (), !*IWorld))
-
 /**
 * Wraps a set of connection handlers and a shared source as a connection task
 */

Libraries/iTasks/Internal/TaskServer.dcl

 definition module iTasks.Internal.TaskServer
 
-import iTasks.Internal.SDS
+from iTasks.Internal.IWorld import :: ConnectionId
+from iTasks.Internal.SDS import :: SDSSource
 
 from Data.Maybe 		import :: Maybe
 from StdFile			import class FileSystem
@@ -9,16 +10,17 @@ from Internet.HTTP		import :: HTTPRequest, :: HTTPResponse
 from System.FilePath    import :: FilePath
 
 from Data.Error               import :: MaybeError
+from Data.Map                 import :: Map
 from iTasks.WF.Definition     import :: TaskId
 from iTasks.Internal.IWorld	  import :: IWorld
 from iTasks.Internal.Task     import :: ConnectionTask, :: TaskException
 from iTasks.Internal.IWorld