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author | 2011-06-30 13:25:37 -0400 | |
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committer | 2011-06-30 13:25:37 -0400 | |
commit | f0497312a77d59f24c8273245ac324b02bb1eb13 (patch) | |
tree | 84fc94674e7bc2d99d1663e020f63d5e7b1c5db7 /Git | |
parent | 0f2859454cb1d1edd779fccd9b35e2b5d78b0861 (diff) |
rename GitQueue to Git.Queue
Diffstat (limited to 'Git')
-rw-r--r-- | Git/Queue.hs | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/Git/Queue.hs b/Git/Queue.hs new file mode 100644 index 000000000..e1ec0cd31 --- /dev/null +++ b/Git/Queue.hs @@ -0,0 +1,89 @@ +{- git repository command queue + - + - Copyright 2010 Joey Hess <joey@kitenet.net> + - + - Licensed under the GNU GPL version 3 or higher. + -} + +module Git.Queue ( + Queue, + empty, + add, + size, + full, + flush +) where + +import qualified Data.Map as M +import System.IO +import System.Cmd.Utils +import Data.String.Utils +import Control.Monad (unless, forM_) +import Utility + +import Git + +{- An action to perform in a git repository. The file to act on + - is not included, and must be able to be appended after the params. -} +data Action = Action { + getSubcommand :: String, + getParams :: [CommandParam] + } deriving (Show, Eq, Ord) + +{- A queue of actions to perform (in any order) on a git repository, + - with lists of files to perform them on. This allows coalescing + - similar git commands. -} +data Queue = Queue Int (M.Map Action [FilePath]) + deriving (Show, Eq) + +{- A recommended maximum size for the queue, after which it should be + - run. + - + - 10240 is semi-arbitrary. If we assume git filenames are between 10 and + - 255 characters long, then the queue will build up between 100kb and + - 2550kb long commands. The max command line length on linux is somewhere + - above 20k, so this is a fairly good balance -- the queue will buffer + - only a few megabytes of stuff and a minimal number of commands will be + - run by xargs. -} +maxSize :: Int +maxSize = 10240 + +{- Constructor for empty queue. -} +empty :: Queue +empty = Queue 0 M.empty + +{- Adds an action to a queue. -} +add :: Queue -> String -> [CommandParam] -> FilePath -> Queue +add (Queue n m) subcommand params file = Queue (n + 1) m' + where + action = Action subcommand params + -- There are probably few items in the map, but there + -- can be a lot of files per item. So, optimise adding + -- files. + m' = M.insertWith' const action files m + files = file:(M.findWithDefault [] action m) + +{- Number of items in a queue. -} +size :: Queue -> Int +size (Queue n _) = n + +{- Is a queue large enough that it should be flushed? -} +full :: Queue -> Bool +full (Queue n _) = n > maxSize + +{- Runs a queue on a git repository. -} +flush :: Repo -> Queue -> IO Queue +flush repo (Queue _ m) = do + forM_ (M.toList m) $ uncurry $ runAction repo + return empty + +{- Runs an Action on a list of files in a git repository. + - + - Complicated by commandline length limits. -} +runAction :: Repo -> Action -> [FilePath] -> IO () +runAction repo action files = unless (null files) runxargs + where + runxargs = pOpen WriteToPipe "xargs" ("-0":"git":params) feedxargs + params = toCommand $ gitCommandLine repo + (Param (getSubcommand action):getParams action) + feedxargs h = hPutStr h $ join "\0" files |