From ec1b9da72f13d74272bc5d48022746af4e943c86 Mon Sep 17 00:00:00 2001
From: Joey Hess <joeyh@joeyh.name>
Date: Tue, 1 Jan 2019 22:44:04 -0400
Subject: [PATCH] avoid abusing from/toRawFilePath for non-FilePaths

---
 Types/UUID.hs                 |  4 ++--
 Utility/FileSystemEncoding.hs | 32 +++++++++++++++++++++-----------
 2 files changed, 23 insertions(+), 13 deletions(-)

diff --git a/Types/UUID.hs b/Types/UUID.hs
index 443cbb1e57..b49c439ca1 100644
--- a/Types/UUID.hs
+++ b/Types/UUID.hs
@@ -44,10 +44,10 @@ instance ToUUID B.ByteString where
 		| otherwise = UUID b
 
 instance FromUUID String where
-	fromUUID s = fromRawFilePath (fromUUID s)
+	fromUUID s = decodeBS' (fromUUID s)
 
 instance ToUUID String where
-	toUUID s = toUUID (toRawFilePath s)
+	toUUID s = toUUID (encodeBS' s)
 
 -- There is no matching FromUUID U.UUID because a git-annex UUID may
 -- be NoUUID or perhaps contain something not allowed in a canonical UUID.
diff --git a/Utility/FileSystemEncoding.hs b/Utility/FileSystemEncoding.hs
index 1c0442f308..9e7e47e49f 100644
--- a/Utility/FileSystemEncoding.hs
+++ b/Utility/FileSystemEncoding.hs
@@ -16,9 +16,11 @@ module Utility.FileSystemEncoding (
 	fromRawFilePath,
 	toRawFilePath,
 	decodeBL,
-	decodeBS,
 	encodeBL,
+	decodeBS,
 	encodeBS,
+	decodeBS',
+	encodeBS',
 	decodeW8,
 	encodeW8,
 	encodeW8NUL,
@@ -119,13 +121,6 @@ decodeBL = encodeW8NUL . L.unpack
 decodeBL = L8.toString
 #endif
 
-decodeBS :: S.ByteString -> FilePath
-#ifndef mingw32_HOST_OS
-decodeBS = encodeW8NUL . S.unpack
-#else
-decodeBS = S8.toString
-#endif
-
 {- Encodes a FilePath into a ByteString, applying the filesystem encoding. -}
 encodeBL :: FilePath -> L.ByteString
 #ifndef mingw32_HOST_OS
@@ -134,6 +129,13 @@ encodeBL = L.pack . decodeW8NUL
 encodeBL = L8.fromString
 #endif
 
+decodeBS :: S.ByteString -> FilePath
+#ifndef mingw32_HOST_OS
+decodeBS = encodeW8NUL . S.unpack
+#else
+decodeBS = S8.toString
+#endif
+
 encodeBS :: FilePath -> S.ByteString
 #ifndef mingw32_HOST_OS
 encodeBS = S.pack . decodeW8NUL
@@ -141,6 +143,14 @@ encodeBS = S.pack . decodeW8NUL
 encodeBS = S8.fromString
 #endif
 
+{- Faster version that assumes the string does not contain NUL;
+ - if it does it will be truncated before the NUL. -}
+decodeBS' :: S.ByteString -> FilePath
+decodeBS' = encodeW8 . S.unpack
+
+encodeBS' :: FilePath -> S.ByteString
+encodeBS' = S.pack . decodeW8
+
 {- Recent versions of the unix package have this alias; defined here
  - for backwards compatibility. -}
 type RawFilePath = S.ByteString
@@ -149,13 +159,13 @@ type RawFilePath = S.ByteString
  - since filename's don't. This should only be used with actual
  - RawFilePaths not arbitrary ByteString that may contain NUL. -}
 fromRawFilePath :: RawFilePath -> FilePath
-fromRawFilePath = encodeW8 . S.unpack
+fromRawFilePath = decodeBS'
 
 {- Note that the FilePath is assumed to never contain NUL,
  - since filename's don't. This should only be used with actual FilePaths
  - not arbitrary String that may contain NUL. -}
 toRawFilePath :: FilePath -> RawFilePath
-toRawFilePath = S.pack . decodeW8
+toRawFilePath = encodeBS'
 
 {- Converts a [Word8] to a FilePath, encoding using the filesystem encoding.
  -
@@ -164,7 +174,7 @@ toRawFilePath = S.pack . decodeW8
  - file system encoding, only complicated by GHC's interface to doing so.
  -
  - Note that the encoding stops at any NUL in the input. FilePaths
- - do not normally contain embedded NUL, but Haskell Strings may.
+ - cannot contain embedded NUL, but Haskell Strings may.
  -}
 {-# NOINLINE encodeW8 #-}
 encodeW8 :: [Word8] -> FilePath