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authorJohn MacFarlane <jgm@berkeley.edu>2021-02-10 23:01:08 -0800
committerJohn MacFarlane <jgm@berkeley.edu>2021-02-11 14:54:28 -0800
commit3c4a58bad03ef56ae9c82b7e7a6ae027514e2bd6 (patch)
tree9a071c2168938bf33f4002d6af523d090d63ef96
parentacc9afaf6f6afa14cbe7cd06798275728e78a529 (diff)
downloadpandoc-3c4a58bad03ef56ae9c82b7e7a6ae027514e2bd6.tar.gz
T.P.Class: Add getTimestamp [API change].
This attempts to read the SOURCE_DATE_EPOCH environment variable and parse a UTC time from it (treating it as a unix date stamp, see https://reproducible-builds.org/specs/source-date-epoch/). If the variable is not set or can't be parsed as a unix date stamp, then the function returns the current date.
-rw-r--r--src/Text/Pandoc/Class/PandocMonad.hs21
1 files changed, 19 insertions, 2 deletions
diff --git a/src/Text/Pandoc/Class/PandocMonad.hs b/src/Text/Pandoc/Class/PandocMonad.hs
index 374da161b..86c8de79e 100644
--- a/src/Text/Pandoc/Class/PandocMonad.hs
+++ b/src/Text/Pandoc/Class/PandocMonad.hs
@@ -51,6 +51,7 @@ module Text.Pandoc.Class.PandocMonad
, setTranslations
, translateTerm
, makeCanonical
+ , getTimestamp
) where
import Codec.Archive.Zip
@@ -59,7 +60,8 @@ import Control.Monad.Except (MonadError (catchError, throwError),
import Data.Digest.Pure.SHA (sha1, showDigest)
import Data.Maybe (fromMaybe)
import Data.Time (UTCTime)
-import Data.Time.Clock.POSIX (POSIXTime, utcTimeToPOSIXSeconds)
+import Data.Time.Clock.POSIX (POSIXTime, utcTimeToPOSIXSeconds,
+ posixSecondsToUTCTime)
import Data.Time.LocalTime (TimeZone, ZonedTime, utcToZonedTime)
import Network.URI ( escapeURIString, nonStrictRelativeTo,
unEscapeString, parseURIReference, isAllowedInURI,
@@ -74,7 +76,7 @@ import Text.Pandoc.Error
import Text.Pandoc.Logging
import Text.Pandoc.MIME (MimeType, getMimeType, extensionFromMimeType)
import Text.Pandoc.MediaBag (MediaBag, lookupMedia)
-import Text.Pandoc.Shared (uriPathToPath)
+import Text.Pandoc.Shared (uriPathToPath, safeRead)
import Text.Pandoc.Translations (Term(..), Translations, lookupTerm,
readTranslations)
import Text.Pandoc.Walk (walkM)
@@ -175,6 +177,21 @@ report msg = do
when (level <= verbosity) $ logOutput msg
modifyCommonState $ \st -> st{ stLog = msg : stLog st }
+-- | Get the time from the @SOURCE_DATE_EPOCH@
+-- environment variable. The variable should contain a
+-- unix time stamp, the number of seconds since midnight Jan 01
+-- 1970 UTC. If the variable is not set or cannot be
+-- parsed as a unix time stamp, the current time is returned.
+-- This function is designed to make possible reproducible
+-- builds in formats that include a creation timestamp.
+getTimestamp :: PandocMonad m => m UTCTime
+getTimestamp = do
+ mbSourceDateEpoch <- lookupEnv "SOURCE_DATE_EPOCH"
+ case mbSourceDateEpoch >>= safeRead of
+ Just (epoch :: Integer) ->
+ return $ posixSecondsToUTCTime $ fromIntegral epoch
+ Nothing -> getCurrentTime
+
-- | Determine whether tracing is enabled. This affects
-- the behavior of 'trace'. If tracing is not enabled,
-- 'trace' does nothing.