-- | Check for overlapping routes.
module Yesod.Routes.Overlap
( findOverlaps
, findOverlapNames
, Overlap (..)
) where
import Yesod.Routes.TH.Types
import Data.List (intercalate)
data Overlap t = Overlap
{ overlapParents :: [String] -> [String] -- ^ parent resource trees
, overlap1 :: ResourceTree t
, overlap2 :: ResourceTree t
}
findOverlaps :: ([String] -> [String]) -> [ResourceTree t] -> [Overlap t]
findOverlaps _ [] = []
findOverlaps front (x:xs) = concatMap (findOverlap front x) xs ++ findOverlaps front xs
findOverlap :: ([String] -> [String]) -> ResourceTree t -> ResourceTree t -> [Overlap t]
findOverlap front x y =
here rest
where
here
| overlaps (resourceTreePieces x) (resourceTreePieces y) (hasSuffix x) (hasSuffix y) = (Overlap front x y:)
| otherwise = id
rest =
case x of
ResourceParent name _ children -> findOverlaps (front . (name:)) children
ResourceLeaf{} -> []
hasSuffix :: ResourceTree t -> Bool
hasSuffix (ResourceLeaf r) =
case resourceDispatch r of
Subsite{} -> True
Methods Just{} _ -> True
Methods Nothing _ -> False
hasSuffix ResourceParent{} = True
overlaps :: [(CheckOverlap, Piece t)] -> [(CheckOverlap, Piece t)] -> Bool -> Bool -> Bool
-- No pieces on either side, will overlap regardless of suffix
overlaps [] [] _ _ = True
-- No pieces on the left, will overlap if the left side has a suffix
overlaps [] _ suffixX _ = suffixX
-- Ditto for the right
overlaps _ [] _ suffixY = suffixY
-- As soon as we ignore a single piece (via CheckOverlap == False), we say that
-- the routes don't overlap at all. In other words, disabling overlap checking
-- on a single piece disables it on the whole route.
overlaps ((False, _):_) _ _ _ = False
overlaps _ ((False, _):_) _ _ = False
-- Compare the actual pieces
overlaps ((True, pieceX):xs) ((True, pieceY):ys) suffixX suffixY =
piecesOverlap pieceX pieceY && overlaps xs ys suffixX suffixY
piecesOverlap :: Piece t -> Piece t -> Bool
-- Statics only match if they equal. Dynamics match with anything
piecesOverlap (Static x) (Static y) = x == y
piecesOverlap _ _ = True
findOverlapNames :: [ResourceTree t] -> [(String, String)]
findOverlapNames =
map go . findOverlaps id
where
go (Overlap front x y) =
(go' $ resourceTreeName x, go' $ resourceTreeName y)
where
go' = intercalate "/" . front . return
{-
-- n^2, should be a way to speed it up
findOverlaps :: [Resource a] -> [[Resource a]]
findOverlaps = go . map justPieces
where
justPieces :: Resource a -> ([Piece a], Resource a)
justPieces r@(Resource _ ps _) = (ps, r)
go [] = []
go (x:xs) = mapMaybe (mOverlap x) xs ++ go xs
mOverlap :: ([Piece a], Resource a) -> ([Piece a], Resource a) ->
Maybe [Resource a]
mOverlap _ _ = Nothing
{- FIXME mOverlap
mOverlap (Static x:xs, xr) (Static y:ys, yr)
| x == y = mOverlap (xs, xr) (ys, yr)
| otherwise = Nothing
mOverlap (MultiPiece _:_, xr) (_, yr) = Just (xr, yr)
mOverlap (_, xr) (MultiPiece _:_, yr) = Just (xr, yr)
mOverlap ([], xr) ([], yr) = Just (xr, yr)
mOverlap ([], _) (_, _) = Nothing
mOverlap (_, _) ([], _) = Nothing
mOverlap (_:xs, xr) (_:ys, yr) = mOverlap (xs, xr) (ys, yr)
-}
-}