1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
|
{- git repository command queue
-
- Copyright 2010,2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE BangPatterns #-}
module Git.Queue (
Queue,
new,
addCommand,
addUpdateIndex,
size,
full,
flush,
) where
import qualified Data.Map as M
import System.IO
import System.Process
import Utility.SafeCommand
import Common
import Git
import Git.Command
import qualified Git.UpdateIndex
{- Queable actions that can be performed in a git repository.
-}
data Action
{- Updating the index file, using a list of streamers that can
- be added to as the queue grows. -}
= UpdateIndexAction
{ getStreamers :: [Git.UpdateIndex.Streamer] -- in reverse order
}
{- A git command to run, on a list of files that can be added to
- as the queue grows. -}
| CommandAction
{ getSubcommand :: String
, getParams :: [CommandParam]
, getFiles :: [FilePath]
}
{- A key that can uniquely represent an action in a Map. -}
data ActionKey = UpdateIndexActionKey | CommandActionKey String
deriving (Eq, Ord)
actionKey :: Action -> ActionKey
actionKey (UpdateIndexAction _) = UpdateIndexActionKey
actionKey CommandAction { getSubcommand = s } = CommandActionKey s
{- 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
{ size :: Int
, _limit :: Int
, items :: M.Map ActionKey Action
}
{- 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. -}
defaultLimit :: Int
defaultLimit = 10240
{- Constructor for empty queue. -}
new :: Maybe Int -> Queue
new lim = Queue 0 (fromMaybe defaultLimit lim) M.empty
{- Adds an git command to the queue.
-
- Git commands with the same subcommand but different parameters are
- assumed to be equivilant enough to perform in any order with the same
- result.
-}
addCommand :: String -> [CommandParam] -> [FilePath] -> Queue -> Repo -> IO Queue
addCommand subcommand params files q repo =
updateQueue action different (length newfiles) q repo
where
key = actionKey action
action = CommandAction
{ getSubcommand = subcommand
, getParams = params
, getFiles = newfiles
}
newfiles = files ++ maybe [] getFiles (M.lookup key $ items q)
different (CommandAction { getSubcommand = s }) = s /= subcommand
different _ = True
{- Adds an update-index streamer to the queue. -}
addUpdateIndex :: Git.UpdateIndex.Streamer -> Queue -> Repo -> IO Queue
addUpdateIndex streamer q repo =
updateQueue action different 1 q repo
where
key = actionKey action
-- the list is built in reverse order
action = UpdateIndexAction $ streamer : streamers
streamers = maybe [] getStreamers $ M.lookup key $ items q
different (UpdateIndexAction _) = False
different _ = True
{- Updates or adds an action in the queue. If the queue already contains a
- different action, it will be flushed; this is to ensure that conflicting
- actions, like add and rm, are run in the right order.-}
updateQueue :: Action -> (Action -> Bool) -> Int -> Queue -> Repo -> IO Queue
updateQueue !action different sizeincrease q repo
| null (filter different (M.elems (items q))) = return $ go q
| otherwise = go <$> flush q repo
where
go q' = newq
where
!newq = q'
{ size = newsize
, items = newitems
}
!newsize = size q' + sizeincrease
!newitems = M.insertWith' const (actionKey action) action (items q')
{- Is a queue large enough that it should be flushed? -}
full :: Queue -> Bool
full (Queue cur lim _) = cur > lim
{- Runs a queue on a git repository. -}
flush :: Queue -> Repo -> IO Queue
flush (Queue _ lim m) repo = do
forM_ (M.elems m) $ runAction repo
return $ Queue 0 lim M.empty
{- Runs an Action on a list of files in a git repository.
-
- Complicated by commandline length limits.
-
- Intentionally runs the command even if the list of files is empty;
- this allows queueing commands that do not need a list of files. -}
runAction :: Repo -> Action -> IO ()
runAction repo (UpdateIndexAction streamers) =
-- list is stored in reverse order
Git.UpdateIndex.streamUpdateIndex repo $ reverse streamers
runAction repo action@(CommandAction {}) =
withHandle StdinHandle createProcessSuccess p $ \h -> do
fileEncoding h
hPutStr h $ intercalate "\0" $ getFiles action
hClose h
where
p = (proc "xargs" params) { env = gitEnv repo }
params = "-0":"git":baseparams
baseparams = toCommand $ gitCommandLine
(Param (getSubcommand action):getParams action) repo
|
