merge from git-annex

* Improve fetching from a remote with an url in host:path format.
* Merge from git-annex.

1 files changed, 58 insertions, 0 deletions

diff --git a/Utility/TimeStamp.hs b/Utility/TimeStamp.hs
new file mode 100644
index 0000000..b740d7b
--- /dev/null
+++ b/Utility/TimeStamp.hs
@@ -0,0 +1,58 @@
+{- timestamp parsing and formatting
+ -
+ - Copyright 2015-2019 Joey Hess <id@joeyh.name>
+ -
+ - License: BSD-2-clause
+ -}
+
+module Utility.TimeStamp (
+	parserPOSIXTime,
+	parsePOSIXTime,
+	formatPOSIXTime,
+) where
+
+import Utility.Data
+
+import Data.Time.Clock.POSIX
+import Data.Time
+import Data.Ratio
+import Control.Applicative
+import qualified Data.ByteString as B
+import qualified Data.ByteString.Char8 as B8
+import qualified Data.Attoparsec.ByteString as A
+import Data.Attoparsec.ByteString.Char8 (char, decimal, signed, isDigit_w8)
+
+{- Parses how POSIXTime shows itself: "1431286201.113452s"
+ - (The "s" is included for historical reasons and is optional.)
+ - Also handles the format with no decimal seconds. -}
+parserPOSIXTime :: A.Parser POSIXTime
+parserPOSIXTime = mkPOSIXTime
+	<$> signed decimal
+	<*> (declen <|> pure (0, 0))
+	<* optional (char 's')
+  where
+	declen :: A.Parser (Integer, Int)
+	declen = do
+		_ <- char '.'
+		b <- A.takeWhile isDigit_w8
+		let len = B.length b
+		d <- either fail pure $
+			A.parseOnly (decimal <* A.endOfInput) b
+		return (d, len)
+
+parsePOSIXTime :: String -> Maybe POSIXTime
+parsePOSIXTime s = eitherToMaybe $ 
+	A.parseOnly (parserPOSIXTime <* A.endOfInput) (B8.pack s)
+
+{- This implementation allows for higher precision in a POSIXTime than
+ - supported by the system's Double, and avoids the complications of
+ - floating point. -}
+mkPOSIXTime :: Integer -> (Integer, Int) -> POSIXTime
+mkPOSIXTime n (d, dlen)
+	| n < 0 = fromIntegral n - fromRational r
+	| otherwise = fromIntegral n + fromRational r
+  where
+	r = d % (10 ^ dlen)
+
+formatPOSIXTime :: String -> POSIXTime -> String
+formatPOSIXTime fmt t = formatTime defaultTimeLocale fmt (posixSecondsToUTCTime t)