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
|
{-# LANGUAGE RecordWildCards #-}
module Database.Persist.SqlBackend.StatementCache
( StatementCache
, StatementCacheKey
, mkCacheKeyFromQuery
, MkStatementCache(..)
, mkSimpleStatementCache
, mkStatementCache
) where
import Data.Foldable
import Data.IORef
import qualified Data.Map as Map
import Database.Persist.SqlBackend.Internal.Statement
import Database.Persist.SqlBackend.Internal.StatementCache
import Data.Map (Map)
import Data.Text (Text)
-- | Configuration parameters for creating a custom statement cache
--
-- @since 2.13.3
data MkStatementCache = MkStatementCache
{ statementCacheLookup :: StatementCacheKey -> IO (Maybe Statement)
-- ^ Retrieve a statement from the cache, or return nothing if it is not found.
--
-- @since 2.13.3
, statementCacheInsert :: StatementCacheKey -> Statement -> IO ()
-- ^ Put a new statement into the cache. An immediate lookup of
-- the statement MUST return the inserted statement for the given
-- cache key. Depending on the implementation, the statement cache MAY
-- choose to evict other statements from the cache within this function.
--
-- @since 2.13.3
, statementCacheClear :: IO ()
-- ^ Remove all statements from the cache. Implementations of this
-- should be sure to call `stmtFinalize` on all statements removed
-- from the cache.
--
-- @since 2.13.3
, statementCacheSize :: IO Int
-- ^ Get the current size of the cache.
--
-- @since 2.13.3
}
-- | Make a simple statement cache that will cache statements if they are not currently cached.
--
-- @since 2.13.3
mkSimpleStatementCache :: IORef (Map Text Statement) -> MkStatementCache
mkSimpleStatementCache stmtMap =
MkStatementCache
{ statementCacheLookup = \sql -> Map.lookup (cacheKey sql) <$> readIORef stmtMap
, statementCacheInsert = \sql stmt ->
modifyIORef' stmtMap (Map.insert (cacheKey sql) stmt)
, statementCacheClear = do
oldStatements <- atomicModifyIORef' stmtMap (\oldStatements -> (Map.empty, oldStatements))
traverse_ stmtFinalize oldStatements
, statementCacheSize = Map.size <$> readIORef stmtMap
}
-- | Create a statement cache.
--
-- @since 2.13.0
mkStatementCache :: MkStatementCache -> StatementCache
mkStatementCache MkStatementCache{..} = StatementCache { .. }
|
