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Each for each metadata field, there's now an automatically maintained "$field-lastchanged" that gives the timestamp of the last change to that field.

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Note that this is a nearly entirely free feature. The data was already
stored in the metadata log in an easily accessible way, and already was
parsed to a time when parsing the log. The generation of the metadata
fields may even be done lazily, although probably not entirely (the map
has to be evaulated to when queried).
This commit is contained in:
Joey Hess 2014-03-18 18:55:43 -04:00
parent fa641dad2d
commit caa97d1271
8 changed files with 94 additions and 23 deletions
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42
Logs/MetaData.hs
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@ -36,26 +36,50 @@ module Logs.MetaData (
import Common.Annex
import Types.MetaData
import Annex.MetaData.StandardFields
import qualified Annex.Branch
import Logs
import Logs.SingleValue
import qualified Data.Set as S
import qualified Data.Map as M
import Data.Time.Clock.POSIX
import Data.Time.Format
import System.Locale
instance SingleValueSerializable MetaData where
serialize = Types.MetaData.serialize
deserialize = Types.MetaData.deserialize
getMetaData :: Key -> Annex (Log MetaData)
getMetaData = readLog . metaDataLogFile
getMetaDataLog :: Key -> Annex (Log MetaData)
getMetaDataLog = readLog . metaDataLogFile
{- Go through the log from oldest to newest, and combine it all
- into a single MetaData representing the current state. -}
- into a single MetaData representing the current state.
-
- Automatically generates a lastchanged metadata for each field that's
- currently set, based on timestamps in the log.
-}
getCurrentMetaData :: Key -> Annex MetaData
getCurrentMetaData = currentMetaData . collect <$$> getMetaData
getCurrentMetaData k = do
ls <- S.toAscList <$> getMetaDataLog k
let loggedmeta = currentMetaData $ combineMetaData $ map value ls
return $ currentMetaData $ unionMetaData loggedmeta
(lastchanged ls loggedmeta)
where
collect = foldl' unionMetaData emptyMetaData . map value . S.toAscList
lastchanged ls (MetaData wanted) =
let m = foldl' (flip M.union) M.empty (map genlastchanged ls)
in MetaData $ M.mapKeys lastChangedField $
-- Only include fields that are currently set.
m `M.intersection` wanted
-- Makes each field have the timestamp as its value.
genlastchanged l =
let MetaData m = value l
ts = S.singleton $ toMetaValue $
formatTime defaultTimeLocale "%s" $
posixSecondsToUTCTime $
changed l
in M.map (const ts) m
{- Adds in some metadata, which can override existing values, or unset
- them, but otherwise leaves any existing metadata as-is. -}
@ -67,10 +91,12 @@ addMetaData k metadata = addMetaData' k metadata =<< liftIO getPOSIXTime
- will tend to be generated across the different log files, and so
- git will be able to pack the data more efficiently. -}
addMetaData' :: Key -> MetaData -> POSIXTime -> Annex ()
addMetaData' k metadata now = Annex.Branch.change (metaDataLogFile k) $
addMetaData' k (MetaData m) now = Annex.Branch.change (metaDataLogFile k) $
showLog . simplifyLog
. S.insert (LogEntry now metadata)
. S.insert (LogEntry now metadata)
. parseLog
where
metadata = MetaData $ M.filterWithKey (\f _ -> not (isLastChangedField f)) m
{- Simplify a log, removing historical values that are no longer
- needed.
@ -148,7 +174,7 @@ copyMetaData :: Key -> Key -> Annex ()
copyMetaData oldkey newkey
| oldkey == newkey = noop
| otherwise = do
l <- getMetaData oldkey
l <- getMetaDataLog oldkey
unless (S.null l) $
Annex.Branch.change (metaDataLogFile newkey) $
const $ showLog l