yesod/yesod-routes/Yesod/Routes.hs
Michael Snoyman 691abb6823 checkStatics
2012-01-03 08:33:44 +02:00

65 lines
1.9 KiB
Haskell

module Yesod.Routes
( Piece (..)
, RouteHandler (..)
, toDispatch
, Dispatch
) where
import Data.Text (Text)
import Web.ClientSession (Key)
import Yesod.Core (Route)
import qualified Data.Vector as V
import Data.Maybe (fromMaybe)
data Piece = StaticPiece Text | SinglePiece
data RouteHandler sub master res = RouteHandler
{ rhPieces :: [Piece]
, rhHasMulti :: Bool
, rhHandler :: Dispatch sub master res
}
type Dispatch sub master res = sub -> Maybe Key -> [Text] -> master -> (Route sub -> Route master) -> Maybe res
toDispatch :: [RouteHandler sub master res] -> Dispatch sub master res
toDispatch rhs =
bcToDispatch bc
where
bc = toBC rhs
bcToDispatch :: ByCount sub master res -> Dispatch sub master res
bcToDispatch (ByCount vec rest) sub mkey ts master toMaster =
go rhs
where
len = length ts
rhs = fromMaybe rest $ vec V.!? len
go [] = Nothing
go (x:xs) = maybe (go xs) Just $ if checkStatics ts (rhPieces x) (rhHasMulti x) then rhHandler x sub mkey ts master toMaster else Nothing
checkStatics [] [] _ = True
checkStatics [] _ _ = False
checkStatics _ [] isMulti = isMulti
checkStatics (_:paths) (SinglePiece:pieces) isMulti = checkStatics paths pieces isMulti
checkStatics (path:paths) (StaticPiece piece:pieces) isMulti =
path == piece && checkStatics paths pieces isMulti
data ByCount sub master res = ByCount
{ bcVector :: !(V.Vector [RouteHandler sub master res])
, bcRest :: ![RouteHandler sub master res]
}
toBC :: [RouteHandler sub master res] -> ByCount sub master res
toBC rhs =
ByCount
{ bcVector = V.map (\i -> filter (canHaveLength i) rhs) $ V.enumFromN 0 (maxLen + 1)
, bcRest = filter rhHasMulti rhs
}
where
maxLen = maximum $ map (length . rhPieces) rhs
canHaveLength i rh =
len == i || (len < i && rhHasMulti rh)
where
len = length $ rhPieces rh