git-annex/Annex/View/ViewedFile.hs
Joey Hess 2b5fa091e2
annex.maxextensionlength for view
view: Support annex.maxextensionlength when generating filenames for the
view branch.

Note that refining an existing view will reuse the extension length that was
configured when initially constructing the view. This is necessarily the case
because it reuses the filenames.

Also view files used to have all extensions at the end, no matter how
many there were. Since annex.maxextensionlength's documentation includes
that it's limited to 2 extensions, I made it consistent with that.

Sponsored-by: k0ld on Patreon
2023-03-24 14:01:38 -04:00

107 lines
3.4 KiB
Haskell

{- filenames (not paths) used in views
-
- Copyright 2014-2023 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
{-# LANGUAGE CPP #-}
module Annex.View.ViewedFile (
ViewedFile,
MkViewedFile,
viewedFileFromReference,
viewedFileFromReference',
viewedFileReuse,
dirFromViewedFile,
prop_viewedFile_roundtrips,
) where
import Annex.Common
import Utility.QuickCheck
import qualified Data.ByteString as S
type FileName = String
type ViewedFile = FileName
type MkViewedFile = FilePath -> ViewedFile
{- Converts a filepath used in a reference branch to the
- filename that will be used in the view.
-
- No two filepaths from the same branch should yield the same result,
- so all directory structure needs to be included in the output filename
- in some way.
-
- So, from dir/subdir/file.foo, generate file_%dir%subdir%.foo
-}
viewedFileFromReference :: GitConfig -> MkViewedFile
viewedFileFromReference g = viewedFileFromReference' (annexMaxExtensionLength g)
viewedFileFromReference' :: Maybe Int -> MkViewedFile
viewedFileFromReference' maxextlen f = concat $
[ escape (fromRawFilePath base')
, if null dirs then "" else "_%" ++ intercalate "%" (map escape dirs) ++ "%"
, escape $ fromRawFilePath $ S.concat extensions'
]
where
(path, basefile) = splitFileName f
dirs = filter (/= ".") $ map dropTrailingPathSeparator (splitPath path)
(base, extensions) = case maxextlen of
Nothing -> splitShortExtensions (toRawFilePath basefile')
Just n -> splitShortExtensions' (n+1) (toRawFilePath basefile')
{- Limit to two extensions maximum. -}
(base', extensions')
| length extensions <= 2 = (base, extensions)
| otherwise =
let (es,more) = splitAt 2 (reverse extensions)
in (base <> mconcat (reverse more), reverse es)
{- On Windows, if the filename looked like "dir/c:foo" then
- basefile would look like it contains a drive letter, which will
- not work. There cannot really be a filename like that, probably,
- but it prevents the test suite failing. -}
(_basedrive, basefile') = splitDrive basefile
{- To avoid collisions with filenames or directories that contain
- '%', and to allow the original directories to be extracted
- from the ViewedFile, '%' is escaped. )
-}
escape :: String -> String
escape = replace "%" (escchar:'%':[]) . replace [escchar] [escchar, escchar]
escchar :: Char
#ifndef mingw32_HOST_OS
escchar = '\\'
#else
-- \ is path separator on Windows, so instead use !
escchar = '!'
#endif
{- For use when operating already within a view, so whatever filepath
- is present in the work tree is already a ViewedFile. -}
viewedFileReuse :: MkViewedFile
viewedFileReuse = takeFileName
{- Extracts from a ViewedFile the directory where the file is located on
- in the reference branch. -}
dirFromViewedFile :: ViewedFile -> FilePath
dirFromViewedFile = joinPath . drop 1 . sep [] ""
where
sep l _ [] = reverse l
sep l curr (c:cs)
| c == '%' = sep (reverse curr:l) "" cs
| c == escchar = case cs of
(c':cs') -> sep l (c':curr) cs'
[] -> sep l curr cs
| otherwise = sep l (c:curr) cs
prop_viewedFile_roundtrips :: TestableFilePath -> Bool
prop_viewedFile_roundtrips tf
-- Relative filenames wanted, not directories.
| any (isPathSeparator) (end f ++ beginning f) = True
| isAbsolute f || isDrive f = True
| otherwise = dir == dirFromViewedFile (viewedFileFromReference' Nothing f)
where
f = fromTestableFilePath tf
dir = joinPath $ beginning $ splitDirectories f