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-rw-r--r--Locations.hs52
1 files changed, 32 insertions, 20 deletions
diff --git a/Locations.hs b/Locations.hs
index 53a80043a..1b5f8108d 100644
--- a/Locations.hs
+++ b/Locations.hs
@@ -1,6 +1,6 @@
{- git-annex file locations
-
- - Copyright 2010 Joey Hess <joey@kitenet.net>
+ - Copyright 2010-2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
@@ -8,6 +8,7 @@
module Locations (
keyFile,
fileKey,
+ keyPaths,
gitAnnexLocation,
annexLocations,
gitAnnexDir,
@@ -59,22 +60,12 @@ annexDir = addTrailingPathSeparator "annex"
objectDir :: FilePath
objectDir = addTrailingPathSeparator $ annexDir </> "objects"
-{- Two different directory hashes may be used. The mixed case hash
- - came first, and is fine, except for the problem of case-strict
- - filesystems such as Linux VFAT (mounted with shortname=mixed),
- - which do not allow using a directory "XX" when "xx" already exists.
- - To support that, some repositories will use a lower case hash. -}
-annexHashes :: [Key -> FilePath]
-annexHashes = [hashDirMixed, hashDirLower]
-
{- Annexed file's possible locations relative to the .git directory.
- There are two different possibilities, using different hashes. -}
annexLocations :: Key -> [FilePath]
annexLocations key = map (annexLocation key) annexHashes
-annexLocation :: Key -> (Key -> FilePath) -> FilePath
-annexLocation key hasher = objectDir </> hasher key </> f </> f
- where
- f = keyFile key
+annexLocation :: Key -> Hasher -> FilePath
+annexLocation key hasher = objectDir </> keyPath key hasher
{- Annexed file's absolute location in a repository.
-
@@ -150,7 +141,7 @@ gitAnnexJournalLock r = gitAnnexDir r </> "journal.lck"
isLinkToAnnex :: FilePath -> Bool
isLinkToAnnex s = ("/.git/" ++ objectDir) `isInfixOf` s
-{- Converts a key into a filename fragment.
+{- Converts a key into a filename fragment without any directory.
-
- Escape "/" in the key name, to keep a flat tree of files and avoid
- issues with keys containing "/../" or ending with "/" etc.
@@ -166,6 +157,22 @@ keyFile :: Key -> FilePath
keyFile key = replace "/" "%" $ replace ":" "&c" $
replace "%" "&s" $ replace "&" "&a" $ show key
+{- A location to store a key on the filesystem. A directory hash is used,
+ - to protect against filesystems that dislike having many items in a
+ - single directory.
+ -
+ - The file is put in a directory with the same name, this allows
+ - write-protecting the directory to avoid accidental deletion of the file.
+ -}
+keyPath :: Key -> Hasher -> FilePath
+keyPath key hasher = hasher key </> f </> f
+ where
+ f = keyFile key
+
+{- All possibile locations to store a key using different directory hashes. -}
+keyPaths :: Key -> [FilePath]
+keyPaths key = map (keyPath key) annexHashes
+
{- Reverses keyFile, converting a filename fragment (ie, the basename of
- the symlink target) into a key. -}
fileKey :: FilePath -> Maybe Key
@@ -178,17 +185,22 @@ prop_idempotent_fileKey :: String -> Bool
prop_idempotent_fileKey s = Just k == fileKey (keyFile k)
where k = stubKey { keyName = s, keyBackendName = "test" }
-{- Given a key, generates a short directory name to put it in,
- - to do hashing to protect against filesystems that dislike having
- - many items in a single directory. -}
-hashDirMixed :: Key -> FilePath
+{- Two different directory hashes may be used. The mixed case hash
+ - came first, and is fine, except for the problem of case-strict
+ - filesystems such as Linux VFAT (mounted with shortname=mixed),
+ - which do not allow using a directory "XX" when "xx" already exists.
+ - To support that, some repositories will use a lower case hash. -}
+type Hasher = Key -> FilePath
+annexHashes :: [Hasher]
+annexHashes = [hashDirMixed, hashDirLower]
+
+hashDirMixed :: Hasher
hashDirMixed k = addTrailingPathSeparator $ take 2 dir </> drop 2 dir
where
dir = take 4 $ display_32bits_as_dir =<< [a,b,c,d]
ABCD (a,b,c,d) = md5 $ Str $ show k
-{- Generates a hash directory that is all lower case. -}
-hashDirLower :: Key -> FilePath
+hashDirLower :: Hasher
hashDirLower k = addTrailingPathSeparator $ take 3 dir </> drop 3 dir
where
dir = take 6 $ md5s $ Str $ show k