git-annex/Command/Whereis.hs
Joey Hess 34c8af74ba fix inversion of control in CommandSeek (no behavior changes)
I've been disliking how the command seek actions were written for some
time, with their inversion of control and ugly workarounds.

The last straw to fix it was sync --content, which didn't fit the
Annex [CommandStart] interface well at all. I have not yet made it take
advantage of the changed interface though.

The crucial change, and probably why I didn't do it this way from the
beginning, is to make each CommandStart action be run with exceptions
caught, and if it fails, increment a failure counter in annex state.
So I finally remove the very first code I wrote for git-annex, which
was before I had exception handling in the Annex monad, and so ran outside
that monad, passing state explicitly as it ran each CommandStart action.

This was a real slog from 1 to 5 am.

Test suite passes.

Memory usage is lower than before, sometimes by a couple of megabytes, and
remains constant, even when running in a large repo, and even when
repeatedly failing and incrementing the error counter. So no accidental
laziness space leaks.

Wall clock speed is identical, even in large repos.

This commit was sponsored by an anonymous bitcoiner.
2014-01-20 04:57:36 -04:00

57 lines
1.7 KiB
Haskell

{- git-annex command
-
- Copyright 2010 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Command.Whereis where
import qualified Data.Map as M
import Common.Annex
import Command
import Remote
import Logs.Trust
import GitAnnex.Options
def :: [Command]
def = [noCommit $ withOptions [jsonOption] $
command "whereis" paramPaths seek SectionQuery
"lists repositories that have file content"]
seek :: CommandSeek
seek ps = do
m <- remoteMap id
withFilesInGit (whenAnnexed $ start m) ps
start :: M.Map UUID Remote -> FilePath -> (Key, Backend) -> CommandStart
start remotemap file (key, _) = do
showStart "whereis" file
next $ perform remotemap key
perform :: M.Map UUID Remote -> Key -> CommandPerform
perform remotemap key = do
locations <- keyLocations key
(untrustedlocations, safelocations) <- trustPartition UnTrusted locations
let num = length safelocations
showNote $ show num ++ " " ++ copiesplural num
pp <- prettyPrintUUIDs "whereis" safelocations
unless (null safelocations) $ showLongNote pp
pp' <- prettyPrintUUIDs "untrusted" untrustedlocations
unless (null untrustedlocations) $ showLongNote $ untrustedheader ++ pp'
forM_ (mapMaybe (`M.lookup` remotemap) locations) $
performRemote key
if null safelocations then stop else next $ return True
where
copiesplural 1 = "copy"
copiesplural _ = "copies"
untrustedheader = "The following untrusted locations may also have copies:\n"
performRemote :: Key -> Remote -> Annex ()
performRemote key remote = maybe noop go $ whereisKey remote
where
go a = do
ls <- a key
unless (null ls) $ showLongNote $ unlines $
map (\l -> name remote ++ ": " ++ l) ls