4301 we need to implement utility to wait for all runnning keys in hl…

…s graph done (#4302)

* wait for database running keys

* add `waitForDatabaseRunningKeysAction`

* add comments

hls-graph/src/Development/IDE/Graph/Internal/Types.hs

@@ -6,6 +6,7 @@
 module Development.IDE.Graph.Internal.Types where
 
 import           Control.Concurrent.STM             (STM)
+import           Control.Monad                      ((>=>))
 import           Control.Monad.Catch
 import           Control.Monad.IO.Class
 import           Control.Monad.Trans.Reader
@@ -78,6 +79,10 @@ data SAction = SAction {
 getDatabase :: Action Database
 getDatabase = Action $ asks actionDatabase
 
+-- | waitForDatabaseRunningKeysAction waits for all keys in the database to finish running.
+waitForDatabaseRunningKeysAction :: Action ()
+waitForDatabaseRunningKeysAction = getDatabase >>= liftIO . waitForDatabaseRunningKeys
+
 ---------------------------------------------------------------------
 -- DATABASE
 
@@ -110,6 +115,9 @@ data Database = Database {
     databaseValues :: !(Map Key KeyDetails)
     }
 
+waitForDatabaseRunningKeys :: Database -> IO ()
+waitForDatabaseRunningKeys = getDatabaseValues >=> mapM_ (waitRunning . snd)
+
 getDatabaseValues :: Database -> IO [(Key, Status)]
 getDatabaseValues = atomically
                   . (fmap.fmap) (second keyStatus)
@@ -136,6 +144,10 @@ getResult (Clean re)           = Just re
 getResult (Dirty m_re)         = m_re
 getResult (Running _ _ _ m_re) = m_re -- watch out: this returns the previous result
 
+waitRunning :: Status -> IO ()
+waitRunning Running{..} = runningWait
+waitRunning _           = return ()
+
 data Result = Result {
     resultValue     :: !Value,
     resultBuilt     :: !Step, -- ^ the step when it was last recomputed