git-annex/Messages.hs
Joey Hess 4224fae71f
optimise read and write for Keys database (untested)
Writes are optimised by queueing up multiple writes when possible.
The queue is flushed after the Annex monad action finishes. That makes it
happen on program termination, and also whenever a nested Annex monad action
finishes.

Reads are optimised by checking once (per AnnexState) if the database
exists. If the database doesn't exist yet, all reads return mempty.

Reads also cause queued writes to be flushed, so reads will always be
consistent with writes (as long as they're made inside the same Annex monad).
A future optimisation path would be to determine when that's not necessary,
which is probably most of the time, and avoid flushing unncessarily.

Design notes for this commit:

- separate reads from writes
- reuse a handle which is left open until program
  exit or until the MVar goes out of scope (and autoclosed then)
- writes are queued
  - queue is flushed periodically
  - immediate queue flush before any read
  - auto-flush queue when database handle is garbage collected
  - flush queue on exit from Annex monad
    (Note that this may happen repeatedly for a single database connection;
    or a connection may be reused for multiple Annex monad actions,
    possibly even concurrent ones.)
- if database does not exist (or is empty) the handle
  is not opened by reads; reads instead return empty results
- writes open the handle if it was not open previously
2015-12-23 19:18:52 -04:00

208 lines
5.4 KiB
Haskell

{- git-annex output messages
-
- Copyright 2010-2014 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Messages (
showStart,
showStart',
showNote,
showAction,
showSideAction,
doSideAction,
doQuietSideAction,
showStoringStateAction,
showOutput,
showLongNote,
showEndOk,
showEndFail,
showEndResult,
endResult,
toplevelWarning,
warning,
earlyWarning,
warningIO,
indent,
maybeShowJSON,
showFullJSON,
showCustom,
showHeader,
showRaw,
setupConsole,
enableDebugOutput,
disableDebugOutput,
debugEnabled,
commandProgressDisabled,
) where
import Text.JSON
import System.Log.Logger
import System.Log.Formatter
import System.Log.Handler (setFormatter)
import System.Log.Handler.Simple
import Common
import Types
import Types.Messages
import Messages.Internal
import qualified Messages.JSON as JSON
import Types.Key
import qualified Annex
showStart :: String -> FilePath -> Annex ()
showStart command file = outputMessage (JSON.start command $ Just file) $
command ++ " " ++ file ++ " "
showStart' :: String -> Key -> Maybe FilePath -> Annex ()
showStart' command key afile = showStart command $
fromMaybe (key2file key) afile
showNote :: String -> Annex ()
showNote s = outputMessage (JSON.note s) $ "(" ++ s ++ ") "
showAction :: String -> Annex ()
showAction s = showNote $ s ++ "..."
showSideAction :: String -> Annex ()
showSideAction m = Annex.getState Annex.output >>= go
where
go st
| sideActionBlock st == StartBlock = do
p
let st' = st { sideActionBlock = InBlock }
Annex.changeState $ \s -> s { Annex.output = st' }
| sideActionBlock st == InBlock = return ()
| otherwise = p
p = outputMessage q $ "(" ++ m ++ "...)\n"
showStoringStateAction :: Annex ()
showStoringStateAction = showSideAction "recording state in git"
{- Performs an action, supressing showSideAction messages. -}
doQuietSideAction :: Annex a -> Annex a
doQuietSideAction = doSideAction' InBlock
{- Performs an action, that may call showSideAction multiple times.
- Only the first will be displayed. -}
doSideAction :: Annex a -> Annex a
doSideAction = doSideAction' StartBlock
doSideAction' :: SideActionBlock -> Annex a -> Annex a
doSideAction' b a = do
o <- Annex.getState Annex.output
set $ o { sideActionBlock = b }
set o `after` a
where
set o = Annex.changeState $ \s -> s { Annex.output = o }
{- Make way for subsequent output of a command. -}
showOutput :: Annex ()
showOutput = unlessM commandProgressDisabled $
outputMessage q "\n"
showLongNote :: String -> Annex ()
showLongNote s = outputMessage (JSON.note s) ('\n' : indent s ++ "\n")
showEndOk :: Annex ()
showEndOk = showEndResult True
showEndFail :: Annex ()
showEndFail = showEndResult False
showEndResult :: Bool -> Annex ()
showEndResult ok = outputMessage (JSON.end ok) $ endResult ok ++ "\n"
endResult :: Bool -> String
endResult True = "ok"
endResult False = "failed"
toplevelWarning :: Bool -> String -> Annex ()
toplevelWarning makeway s = warning' makeway ("git-annex: " ++ s)
warning :: String -> Annex ()
warning = warning' True . indent
earlyWarning :: String -> Annex ()
earlyWarning = warning' False
warning' :: Bool -> String -> Annex ()
warning' makeway w = do
when makeway $
outputMessage q "\n"
outputError (w ++ "\n")
{- Not concurrent output safe. -}
warningIO :: String -> IO ()
warningIO w = do
putStr "\n"
hFlush stdout
hPutStrLn stderr w
indent :: String -> String
indent = intercalate "\n" . map (\l -> " " ++ l) . lines
{- Shows a JSON fragment only when in json mode. -}
maybeShowJSON :: JSON a => [(String, a)] -> Annex ()
maybeShowJSON v = withOutputType $ liftIO . go
where
go JSONOutput = JSON.add v
go _ = return ()
{- Shows a complete JSON value, only when in json mode. -}
showFullJSON :: JSON a => [(String, a)] -> Annex Bool
showFullJSON v = withOutputType $ liftIO . go
where
go JSONOutput = JSON.complete v >> return True
go _ = return False
{- Performs an action that outputs nonstandard/customized output, and
- in JSON mode wraps its output in JSON.start and JSON.end, so it's
- a complete JSON document.
- This is only needed when showStart and showEndOk is not used.
-}
showCustom :: String -> Annex Bool -> Annex ()
showCustom command a = do
outputMessage (JSON.start command Nothing) ""
r <- a
outputMessage (JSON.end r) ""
showHeader :: String -> Annex ()
showHeader h = outputMessage q $ (h ++ ": ")
showRaw :: String -> Annex ()
showRaw s = outputMessage q (s ++ "\n")
setupConsole :: IO ()
setupConsole = do
s <- setFormatter
<$> streamHandler stderr DEBUG
<*> pure preciseLogFormatter
updateGlobalLogger rootLoggerName (setLevel NOTICE . setHandlers [s])
setConsoleEncoding
{- Log formatter with precision into fractions of a second. -}
preciseLogFormatter :: LogFormatter a
preciseLogFormatter = tfLogFormatter "%F %X%Q" "[$time] $msg"
enableDebugOutput :: IO ()
enableDebugOutput = updateGlobalLogger rootLoggerName $ setLevel DEBUG
disableDebugOutput :: IO ()
disableDebugOutput = updateGlobalLogger rootLoggerName $ setLevel NOTICE
{- Checks if debugging is enabled. -}
debugEnabled :: IO Bool
debugEnabled = do
l <- getRootLogger
return $ getLevel l <= Just DEBUG
{- Should commands that normally output progress messages have that
- output disabled? -}
commandProgressDisabled :: Annex Bool
commandProgressDisabled = withOutputType $ \t -> return $ case t of
QuietOutput -> True
JSONOutput -> True
NormalOutput -> False
ConcurrentOutput _ -> True