Statistics
| Branch: | Tag: | Revision:

root / htools / Ganeti / HTools / Container.hs @ ebf38064

History | View | Annotate | Download (2.4 kB)

1
{-| Module abstracting the node and instance container implementation.
2

    
3
This is currently implemented on top of an 'IntMap', which seems to
4
give the best performance for our workload.
5

    
6
-}
7

    
8
{-
9

    
10
Copyright (C) 2009, 2010, 2011 Google Inc.
11

    
12
This program is free software; you can redistribute it and/or modify
13
it under the terms of the GNU General Public License as published by
14
the Free Software Foundation; either version 2 of the License, or
15
(at your option) any later version.
16

    
17
This program is distributed in the hope that it will be useful, but
18
WITHOUT ANY WARRANTY; without even the implied warranty of
19
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
20
General Public License for more details.
21

    
22
You should have received a copy of the GNU General Public License
23
along with this program; if not, write to the Free Software
24
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
25
02110-1301, USA.
26

    
27
-}
28

    
29
module Ganeti.HTools.Container
30
  ( -- * Types
31
    Container
32
  , Key
33
  -- * Creation
34
  , IntMap.empty
35
  , IntMap.singleton
36
  , IntMap.fromList
37
  -- * Query
38
  , IntMap.size
39
  , IntMap.null
40
  , find
41
  , IntMap.findMax
42
  , IntMap.member
43
  -- * Update
44
  , add
45
  , addTwo
46
  , IntMap.map
47
  , IntMap.mapAccum
48
  , IntMap.filter
49
  -- * Conversion
50
  , IntMap.elems
51
  , IntMap.keys
52
  -- * Element functions
53
  , nameOf
54
  , findByName
55
  ) where
56

    
57
import qualified Data.IntMap as IntMap
58

    
59
import qualified Ganeti.HTools.Types as T
60

    
61
-- | Our key type.
62

    
63
type Key = IntMap.Key
64

    
65
-- | Our container type.
66
type Container = IntMap.IntMap
67

    
68
-- | Locate a key in the map (must exist).
69
find :: Key -> Container a -> a
70
find k = (IntMap.! k)
71

    
72
-- | Add or update one element to the map.
73
add :: Key -> a -> Container a -> Container a
74
add = IntMap.insert
75

    
76
-- | Add or update two elements of the map.
77
addTwo :: Key -> a -> Key -> a -> Container a -> Container a
78
addTwo k1 v1 k2 v2 = add k1 v1 . add k2 v2
79

    
80
-- | Compute the name of an element in a container.
81
nameOf :: (T.Element a) => Container a -> Key -> String
82
nameOf c k = T.nameOf $ find k c
83

    
84
-- | Find an element by name in a Container; this is a very slow function.
85
findByName :: (T.Element a, Monad m) =>
86
              Container a -> String -> m a
87
findByName c n =
88
  let all_elems = IntMap.elems c
89
      result = filter ((n `elem`) . T.allNames) all_elems
90
  in case result of
91
       [item] -> return item
92
       _ -> fail $ "Wrong number of elems found with name " ++ n