diff options
Diffstat (limited to 'compiler/GHC/Utils/Misc.hs')
| -rw-r--r-- | compiler/GHC/Utils/Misc.hs | 25 |
1 files changed, 21 insertions, 4 deletions
diff --git a/compiler/GHC/Utils/Misc.hs b/compiler/GHC/Utils/Misc.hs index 8dde1c7296..d19d78c876 100644 --- a/compiler/GHC/Utils/Misc.hs +++ b/compiler/GHC/Utils/Misc.hs @@ -66,7 +66,7 @@ module GHC.Utils.Misc ( dropTail, capitalise, -- * Sorting - sortWith, minWith, nubSort, ordNub, + sortWith, minWith, nubSort, ordNub, ordNubOn, -- * Comparisons isEqual, eqListBy, eqMaybeBy, @@ -100,6 +100,7 @@ module GHC.Utils.Misc ( doesDirNameExist, getModificationUTCTime, modificationTimeIfExists, + fileHashIfExists, withAtomicRename, -- * Filenames and paths @@ -132,6 +133,7 @@ import GHC.Prelude import GHC.Utils.Exception import GHC.Utils.Panic.Plain import GHC.Utils.Constants +import GHC.Utils.Fingerprint import Data.Data import qualified Data.List as List @@ -639,13 +641,18 @@ nubSort = Set.toAscList . Set.fromList -- | Remove duplicates but keep elements in order. -- O(n * log n) ordNub :: Ord a => [a] -> [a] -ordNub xs +ordNub xs = ordNubOn id xs + +-- | Remove duplicates but keep elements in order. +-- O(n * log n) +ordNubOn :: Ord b => (a -> b) -> [a] -> [a] +ordNubOn f xs = go Set.empty xs where go _ [] = [] go s (x:xs) - | Set.member x s = go s xs - | otherwise = x : go (Set.insert x s) xs + | Set.member (f x) s = go s xs + | otherwise = x : go (Set.insert (f x) s) xs {- @@ -1292,6 +1299,16 @@ modificationTimeIfExists f = else ioError e -- -------------------------------------------------------------- +-- check existence & hash at the same time + +fileHashIfExists :: FilePath -> IO (Maybe Fingerprint) +fileHashIfExists f = + (do t <- getFileHash f; return (Just t)) + `catchIO` \e -> if isDoesNotExistError e + then return Nothing + else ioError e + +-- -------------------------------------------------------------- -- atomic file writing by writing to a temporary file first (see #14533) -- -- This should be used in all cases where GHC writes files to disk |