git-annex/Annex/MetaData/StandardFields.hs
Joey Hess caa97d1271 Each for each metadata field, there's now an automatically maintained "$field-lastchanged" that gives the timestamp of the last change to that field.
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).
2014-03-18 18:55:43 -04:00

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Haskell

{- git-annex metadata, standard fields
-
- Copyright 2014 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Annex.MetaData.StandardFields (
tagMetaField,
yearMetaField,
monthMetaField,
lastChangedField,
isLastChangedField
) where
import Types.MetaData
import Data.List
tagMetaField :: MetaField
tagMetaField = mkMetaFieldUnchecked "tag"
yearMetaField :: MetaField
yearMetaField = mkMetaFieldUnchecked "year"
monthMetaField :: MetaField
monthMetaField = mkMetaFieldUnchecked "month"
lastChangedField :: MetaField -> MetaField
lastChangedField f = mkMetaFieldUnchecked (fromMetaField f ++ lastchanged)
isLastChangedField :: MetaField -> Bool
isLastChangedField f = lastchanged `isSuffixOf` s && s /= lastchanged
where
s = fromMetaField f
lastchanged :: String
lastchanged = "-lastchanged"