git-annex/Git/Log.hs
Joey Hess 561c036664
split out generic git log parser
Sponsored-By: Jack Hill on Patreon
2023-11-10 15:40:03 -04:00

107 lines
2.6 KiB
Haskell

{- git log
-
- Copyright 2023 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
module Git.Log where
import Common
import Git
import Git.Command
import Data.Time
import Data.Time.Clock.POSIX
-- A change made to a file.
data RefChange t = RefChange
{ changetime :: POSIXTime
, changed :: t
, changedfile :: FilePath
, oldref :: Ref
, newref :: Ref
}
deriving (Show)
-- Get the git log. Note that the returned cleanup action should only be
-- run after processing the returned list.
getGitLog
:: Ref
-> [FilePath]
-> [CommandParam]
-> (FilePath -> Maybe t)
-> Repo
-> IO ([RefChange t], IO Bool)
getGitLog ref fs os fileselector repo = do
(ls, cleanup) <- pipeNullSplit ps repo
return (parseGitRawLog fileselector (map decodeBL ls), cleanup)
where
ps =
[ Param "log"
, Param "-z"
, Param ("--pretty=format:"++commitinfoFormat)
, Param "--raw"
, Param "--no-abbrev"
, Param "--no-renames"
] ++ os ++
[ Param (fromRef ref)
, Param "--"
] ++ map Param fs
-- The commitinfo is the timestamp of the commit, followed by
-- the commit hash and then the commit's parents, separated by spaces.
commitinfoFormat :: String
commitinfoFormat = "%ct"
-- Parses chunked git log --raw output generated by getGitLog,
-- which looks something like:
--
-- [ "commitinfo\n:changeline"
-- , "filename"
-- , ""
-- , "commitinfo\n:changeline"
-- , "filename"
-- , ":changeline"
-- , "filename"
-- , ""
-- ]
--
-- The commitinfo is not included before all changelines, so
-- keep track of the most recently seen commitinfo.
parseGitRawLog :: (FilePath -> Maybe t) -> [String] -> [RefChange t]
parseGitRawLog fileselector = parse epoch
where
epoch = toEnum 0 :: POSIXTime
parse oldts ([]:rest) = parse oldts rest
parse oldts (c1:c2:rest) = case mrc of
Just rc -> rc : parse ts rest
Nothing -> parse ts (c2:rest)
where
(ts, cl) = case separate (== '\n') c1 of
(cl', []) -> (oldts, cl')
(tss, cl') -> (parseTimeStamp tss, cl')
mrc = do
(old, new) <- parseRawChangeLine cl
v <- fileselector c2
return $ RefChange
{ changetime = ts
, changed = v
, changedfile = c2
, oldref = old
, newref = new
}
parse _ _ = []
-- Parses something like ":100644 100644 oldsha newsha M"
-- extracting the shas.
parseRawChangeLine :: String -> Maybe (Git.Ref, Git.Ref)
parseRawChangeLine = go . words
where
go (_:_:oldsha:newsha:_) =
Just (Git.Ref (encodeBS oldsha), Git.Ref (encodeBS newsha))
go _ = Nothing
parseTimeStamp :: String -> POSIXTime
parseTimeStamp = utcTimeToPOSIXSeconds . fromMaybe (giveup "bad timestamp") .
parseTimeM True defaultTimeLocale "%s"