cc17ac423b
Considerable difficulty to work around an import cycle. Had to move the list of backends (except for VURL) to Backend.Variety to VURL could use it. Sponsored-by: Kevin Mueller on Patreon
77 lines
2.4 KiB
Haskell
77 lines
2.4 KiB
Haskell
{- git-annex backend utilities
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-
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- Copyright 2012-2024 Joey Hess <id@joeyh.name>
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-
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- Licensed under the GNU AGPL version 3 or higher.
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-}
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{-# LANGUAGE OverloadedStrings #-}
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module Backend.Utilities where
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import Annex.Common
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import qualified Annex
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import Utility.Hash
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import Types.Key
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import Types.KeySource
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import qualified Data.ByteString as S
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import qualified Data.ByteString.Short as S (ShortByteString, toShort)
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import qualified Data.ByteString.Lazy as L
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import qualified System.FilePath.ByteString as P
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import Data.Char
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import Data.Word
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{- Generates a keyName from an input string. Takes care of sanitizing it.
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- If it's not too long, the full string is used as the keyName.
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- Otherwise, it's truncated, and its md5 is prepended to ensure a unique
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- key. -}
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genKeyName :: String -> S.ShortByteString
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genKeyName s
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-- Avoid making keys longer than the length of a SHA256 checksum.
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| bytelen > sha256len = S.toShort $ encodeBS $
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truncateFilePath (sha256len - md5len - 1) s' ++ "-" ++
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show (md5 bl)
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| otherwise = S.toShort $ encodeBS s'
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where
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s' = preSanitizeKeyName s
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bl = encodeBL s
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bytelen = fromIntegral $ L.length bl
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sha256len = 64
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md5len = 32
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{- Converts a key to a version that includes an extension from the
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- file that the key was generated from. -}
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addE :: KeySource -> (KeyVariety -> KeyVariety) -> Key -> Annex Key
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addE source sethasext k = do
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maxlen <- annexMaxExtensionLength <$> Annex.getGitConfig
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let ext = selectExtension maxlen (keyFilename source)
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return $ alterKey k $ \d -> d
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{ keyName = keyName d <> S.toShort ext
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, keyVariety = sethasext (keyVariety d)
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}
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selectExtension :: Maybe Int -> RawFilePath -> S.ByteString
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selectExtension maxlen f
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| null es = ""
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| otherwise = S.intercalate "." ("":es)
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where
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es = filter (not . S.null) $ reverse $
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take 2 $ filter (S.all validInExtension) $
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takeWhile shortenough $
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reverse $ S.split (fromIntegral (ord '.')) (P.takeExtensions f')
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shortenough e = S.length e <= fromMaybe maxExtensionLen maxlen
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-- Avoid treating a file ".foo" as having its whole name as an
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-- extension.
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f' = S.dropWhile (== fromIntegral (ord '.')) (P.takeFileName f)
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validInExtension :: Word8 -> Bool
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validInExtension c
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| isAlphaNum (chr (fromIntegral c)) = True
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| fromIntegral c == ord '.' = True
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| c <= 127 = False -- other ascii: spaces, punctuation, control chars
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| otherwise = True -- utf8 is allowed, also other encodings
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maxExtensionLen :: Int
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maxExtensionLen = 4 -- long enough for "jpeg"
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