40ecf58d4b
This does not change the overall license of the git-annex program, which was already AGPL due to a number of sources files being AGPL already. Legally speaking, I'm adding a new license under which these files are now available; I already released their current contents under the GPL license. Now they're dual licensed GPL and AGPL. However, I intend for all my future changes to these files to only be released under the AGPL license, and I won't be tracking the dual licensing status, so I'm simply changing the license statement to say it's AGPL. (In some cases, others wrote parts of the code of a file and released it under the GPL; but in all cases I have contributed a significant portion of the code in each file and it's that code that is getting the AGPL license; the GPL license of other contributors allows combining with AGPL code.)
55 lines
1.5 KiB
Haskell
55 lines
1.5 KiB
Haskell
{- git-annex single-value log, pure operations
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-
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- Copyright 2014-2019 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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module Logs.SingleValue.Pure where
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import Annex.Common
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import Logs.Line
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import Annex.VectorClock
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import qualified Data.Set as S
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import qualified Data.ByteString as B
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import qualified Data.ByteString.Lazy as L
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import qualified Data.Attoparsec.ByteString.Lazy as A
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import Data.Attoparsec.ByteString.Char8 (char)
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import Data.ByteString.Builder
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class SingleValueSerializable v where
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serialize :: v -> B.ByteString
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deserialize :: B.ByteString -> Maybe v
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data LogEntry v = LogEntry
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{ changed :: VectorClock
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, value :: v
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} deriving (Eq, Ord)
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type Log v = S.Set (LogEntry v)
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buildLog :: (SingleValueSerializable v) => Log v -> Builder
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buildLog = mconcat . map genline . S.toList
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where
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genline (LogEntry c v) =
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buildVectorClock c <> sp <> byteString (serialize v) <> nl
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sp = charUtf8 ' '
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nl = charUtf8 '\n'
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parseLog :: (Ord v, SingleValueSerializable v) => L.ByteString -> Log v
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parseLog = S.fromList . fromMaybe []
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. A.maybeResult . A.parse (logParser <* A.endOfInput)
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logParser :: SingleValueSerializable v => A.Parser [LogEntry v]
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logParser = parseLogLines $ LogEntry
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<$> vectorClockParser
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<* char ' '
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<*> (parsevalue =<< A.takeByteString)
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where
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parsevalue = maybe (fail "log line parse failure") return . deserialize
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newestValue :: Log v -> Maybe v
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newestValue s
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| S.null s = Nothing
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| otherwise = Just (value $ S.findMax s)
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