44 lines
1.3 KiB
Haskell
44 lines
1.3 KiB
Haskell
{- git-annex .variant files for automatic merge conflict resolution
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-
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- Copyright 2014 Joey Hess <id@joeyh.name>
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-
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- Licensed under the GNU GPL version 3 or higher.
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-}
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module Annex.VariantFile where
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import Annex.Common
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import Data.Hash.MD5
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variantMarker :: String
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variantMarker = ".variant-"
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mkVariant :: FilePath -> String -> FilePath
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mkVariant file variant = takeDirectory file
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</> dropExtension (takeFileName file)
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++ variantMarker ++ variant
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++ takeExtension file
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{- The filename to use when resolving a conflicted merge of a file,
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- that points to a key.
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-
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- Something derived from the key needs to be included in the filename,
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- but rather than exposing the whole key to the user, a very weak hash
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- is used. There is a very real, although still unlikely, chance of
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- conflicts using this hash.
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-
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- In the event that there is a conflict with the filename generated
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- for some other key, that conflict will itself be handled by the
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- conflicted merge resolution code. That case is detected, and the full
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- key is used in the filename.
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-}
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variantFile :: FilePath -> Key -> FilePath
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variantFile file key
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| doubleconflict = mkVariant file (key2file key)
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| otherwise = mkVariant file (shortHash $ key2file key)
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where
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doubleconflict = variantMarker `isInfixOf` file
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shortHash :: String -> String
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shortHash = take 4 . md5s . md5FilePath
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