79 lines
2.3 KiB
Haskell
79 lines
2.3 KiB
Haskell
module Propellor.Property where
|
|
|
|
import System.Directory
|
|
import Control.Monad
|
|
import Data.Monoid
|
|
|
|
import Propellor.Types
|
|
import Propellor.Engine
|
|
import Utility.Monad
|
|
|
|
makeChange :: IO () -> IO Result
|
|
makeChange a = a >> return MadeChange
|
|
|
|
noChange :: IO Result
|
|
noChange = return NoChange
|
|
|
|
-- | Combines a list of properties, resulting in a single property
|
|
-- that when run will run each property in the list in turn,
|
|
-- and print out the description of each as it's run. Does not stop
|
|
-- on failure; does propigate overall success/failure.
|
|
propertyList :: Desc -> [Property] -> Property
|
|
propertyList desc ps = Property desc $ ensureProperties' ps
|
|
|
|
-- | Combines a list of properties, resulting in one property that
|
|
-- ensures each in turn, stopping on failure.
|
|
combineProperties :: Desc -> [Property] -> Property
|
|
combineProperties desc ps = Property desc $ go ps NoChange
|
|
where
|
|
go [] rs = return rs
|
|
go (l:ls) rs = do
|
|
r <- ensureProperty l
|
|
case r of
|
|
FailedChange -> return FailedChange
|
|
_ -> go ls (r <> rs)
|
|
|
|
-- | Makes a perhaps non-idempotent Property be idempotent by using a flag
|
|
-- file to indicate whether it has run before.
|
|
-- Use with caution.
|
|
flagFile :: Property -> FilePath -> Property
|
|
flagFile property flagfile = Property (propertyDesc property) $
|
|
go =<< doesFileExist flagfile
|
|
where
|
|
go True = return NoChange
|
|
go False = do
|
|
r <- ensureProperty property
|
|
when (r == MadeChange) $
|
|
writeFile flagfile ""
|
|
return r
|
|
|
|
--- | Whenever a change has to be made for a Property, causes a hook
|
|
-- Property to also be run, but not otherwise.
|
|
onChange :: Property -> Property -> Property
|
|
property `onChange` hook = Property (propertyDesc property) $ do
|
|
r <- ensureProperty property
|
|
case r of
|
|
MadeChange -> do
|
|
r' <- ensureProperty hook
|
|
return $ r <> r'
|
|
_ -> return r
|
|
|
|
-- | Indicates that the first property can only be satisfied once
|
|
-- the second is.
|
|
requires :: Property -> Property -> Property
|
|
x `requires` y = combineProperties (propertyDesc x) [y, x]
|
|
|
|
describe :: Property -> Desc -> Property
|
|
describe p d = p { propertyDesc = d }
|
|
|
|
(==>) :: Desc -> Property -> Property
|
|
(==>) = flip describe
|
|
infixl 1 ==>
|
|
|
|
-- | Makes a Property only be performed when a test succeeds.
|
|
check :: IO Bool -> Property -> Property
|
|
check c property = Property (propertyDesc property) $ ifM c
|
|
( ensureProperty property
|
|
, return NoChange
|
|
)
|