annex.maxextensionlength

Added annex.maxextensionlength for use cases where extensions longer than 4
characters are needed.

This commit was sponsored by Henrik Riomar on Patreon.

Backend/Hash.hs

@@ -98,13 +98,16 @@ keyValue hash source = do
 keyValueE :: Hash -> KeySource -> Annex (Maybe Key)
 keyValueE hash source = keyValue hash source >>= maybe (return Nothing) addE
   where
-	addE k = return $ Just $ k
-		{ keyName = keyName k ++ selectExtension (keyFilename source)
-		, keyVariety = hashKeyVariety hash (HasExt True)
-		}
+	addE k = do
+		maxlen <- annexMaxExtensionLength <$> Annex.getGitConfig
+		let ext = selectExtension maxlen (keyFilename source)
+		return $ Just $ k
+			{ keyName = keyName k ++ ext
+			, keyVariety = hashKeyVariety hash (HasExt True)
+			}
 
-selectExtension :: FilePath -> String
-selectExtension f
+selectExtension :: Maybe Int -> FilePath -> String
+selectExtension maxlen f
 	| null es = ""
 	| otherwise = intercalate "." ("":es)
   where
@@ -112,7 +115,10 @@ selectExtension f
 		take 2 $ filter (all validInExtension) $
 		takeWhile shortenough $
 		reverse $ splitc '.' $ takeExtensions f
-	shortenough e = length e <= 4 -- long enough for "jpeg"
+	shortenough e = length e <= fromMaybe maxExtensionLen maxlen
+
+maxExtensionLen :: Int
+maxExtensionLen = 4 -- long enough for "jpeg"
 
 {- A key's checksum is checked during fsck when it's content is present
  - except for in fast mode. -}
@@ -162,8 +168,12 @@ needsUpgrade key = or
 	, not (hasExt (keyVariety key)) && keyHash key /= keyName key
 	]
 
-trivialMigrate :: Key -> Backend -> AssociatedFile -> Maybe Key
-trivialMigrate oldkey newbackend afile
+trivialMigrate :: Key -> Backend -> AssociatedFile -> Annex (Maybe Key)
+trivialMigrate oldkey newbackend afile = trivialMigrate' oldkey newbackend afile
+	<$> (annexMaxExtensionLength <$> Annex.getGitConfig)
+
+trivialMigrate' :: Key -> Backend -> AssociatedFile -> Maybe Int -> Maybe Key
+trivialMigrate' oldkey newbackend afile maxextlen
 	{- Fast migration from hashE to hash backend. -}
 	| migratable && hasExt oldvariety = Just $ oldkey
 		{ keyName = keyHash oldkey
@@ -173,7 +183,8 @@ trivialMigrate oldkey newbackend afile
 	| migratable && hasExt newvariety = case afile of
 		AssociatedFile Nothing -> Nothing
 		AssociatedFile (Just file) -> Just $ oldkey
-			{ keyName = keyHash oldkey ++ selectExtension file
+			{ keyName = keyHash oldkey 
+				++ selectExtension maxextlen file
 			, keyVariety = newvariety
 			}
 	{- Upgrade to fix bad previous migration that created a

Backend/WORM.hs

@@ -47,11 +47,11 @@ keyValue source = do
 needsUpgrade :: Key -> Bool
 needsUpgrade key = ' ' `elem` keyName key
 
-removeSpaces :: Key -> Backend -> AssociatedFile -> Maybe Key
+removeSpaces :: Key -> Backend -> AssociatedFile -> Annex (Maybe Key)
 removeSpaces oldkey newbackend _
-	| migratable = Just $ oldkey
+	| migratable = return $ Just $ oldkey
 		{ keyName = reSanitizeKeyName (keyName oldkey) }
-	| otherwise = Nothing
+	| otherwise = return Nothing
   where
 	migratable = oldvariety == newvariety
 	oldvariety = keyVariety oldkey

CHANGELOG

@@ -11,6 +11,8 @@ git-annex (6.20180914) UNRELEASED; urgency=medium
     as the rest of git's interface is used in newline-safe ways.
   * Added -z option to git-annex commands that use --batch, useful for
     supporting filenames containing newlines.
+  * Added annex.maxextensionlength for use cases where extensions longer
+    than 4 characters are needed.
   * More FreeBSD build fixes.
 
   [ Yaroslav Halchenko ]

Command/Migrate.hs

@@ -65,7 +65,7 @@ upgradableKey backend key = isNothing (keySize key) || backendupgradable
  - generated.
  -}
 perform :: FilePath -> Key -> Backend -> Backend -> CommandPerform
-perform file oldkey oldbackend newbackend = go =<< genkey
+perform file oldkey oldbackend newbackend = go =<< genkey (fastMigrate oldbackend)
   where
 	go Nothing = stop
 	go (Just (newkey, knowngoodcontent))
@@ -84,7 +84,8 @@ perform file oldkey oldbackend newbackend = go =<< genkey
 			next $ Command.ReKey.cleanup file oldkey newkey
 		, error "failed"
 		)
-	genkey = case maybe Nothing (\fm -> fm oldkey newbackend afile) (fastMigrate oldbackend) of
+	genkey Nothing = return Nothing
+	genkey (Just fm) = fm oldkey newbackend afile >>= \case
 		Just newkey -> return $ Just (newkey, True)
 		Nothing -> do
 			content <- calcRepo $ gitAnnexLocation oldkey

Types/Backend.hs

@@ -21,7 +21,7 @@ data BackendA a = Backend
 	, canUpgradeKey :: Maybe (Key -> Bool)
 	-- Checks if there is a fast way to migrate a key to a different
 	-- backend (ie, without re-hashing).
-	, fastMigrate :: Maybe (Key -> BackendA a -> AssociatedFile -> Maybe Key)
+	, fastMigrate :: Maybe (Key -> BackendA a -> AssociatedFile -> a (Maybe Key))
 	-- Checks if a key is known (or assumed) to always refer to the
 	-- same data.
 	, isStableKey :: Key -> Bool

Types/GitConfig.hs

@@ -98,6 +98,7 @@ data GitConfig = GitConfig
 	, annexAllowedUrlSchemes :: S.Set Scheme
 	, annexAllowedHttpAddresses :: String
 	, annexAllowUnverifiedDownloads :: Bool
+	, annexMaxExtensionLength :: Maybe Int
 	, coreSymlinks :: Bool
 	, coreSharedRepository :: SharedRepository
 	, receiveDenyCurrentBranch :: DenyCurrentBranch
@@ -171,6 +172,7 @@ extractGitConfig r = GitConfig
 		getmaybe (annex "security.allowed-http-addresses")
 	, annexAllowUnverifiedDownloads = (== Just "ACKTHPPT") $
 		getmaybe (annex "security.allow-unverified-downloads")
+	, annexMaxExtensionLength = getmayberead (annex "maxextensionlength")
 	, coreSymlinks = getbool "core.symlinks" True
 	, coreSharedRepository = getSharedRepository r
 	, receiveDenyCurrentBranch = getDenyCurrentBranch r

doc/git-annex.mdwn

@@ -865,6 +865,13 @@ Here are all the supported configuration settings.
   To configure the behavior in new clones of the repository,
   this can be set in [[git-annex-config]].
 
+* `annex.maxextensionlength`
+
+  Maximum length of what is considered a filename extension when adding a
+  file to a backend that preserves filename extensions. The default length
+  is 4, which allows extensions like "jpeg". The dot before the extension
+  is not counted part of its length.
+
 * `annex.diskreserve`
 
   Amount of disk space to reserve. Disk space is checked when transferring

doc/todo/support_longer_file_extensions.mdwn

@@ -3,3 +3,5 @@ file myfile.fasta becomes the symlink .git/annex/objects/xx/xx/key/myfile.fasta
 .git/annex/objects/xx/xx/key/anotherfile.fasta which is a hardlink to myfile.fasta . An added plus is that the symlinks checked into git typically becomes shorter. Or, for better backwards compatibility, the symlinks checked into git don't change, but
 .git/annex/objects/xx/xx/key/key becomes a symlink to .git/annex/objects/xx/xx/key/myfile.fasta .   However, if there is anotherfile.fasta with the same key, its symlink will still end up terminating at myfile.fasta rather than anotherfile.fasta .
 It's useful to preserve full filenames, because it's not uncommon to e.g. encode parameter information in filenames (myresult.threshold100.dat); and it's not uncommon to call something like python's os.path.realpath to unwind symlink chains before processing a file.
+
+> [[done]] --[[Joey]]

doc/todo/support_longer_file_extensions/comment_2_a01fbe5b4f72989532051f5e1bb55104._comment

@@ -0,0 +1,7 @@
+[[!comment format=mdwn
+ username="joey"
+ subject="""comment 2"""
+ date="2018-09-24T15:50:47Z"
+ content="""
+Added annex.maxextensionlength configuration.
+"""]]