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|
module Database.KeyDatabaseSQLite (
Key, KeyPred,
Query, runQ, transformQ, getDB,
Transaction, TError(..), TErrorKind(..), showTError, runT, runJustT,
returnT, doneT, errorT, failT, (|>>=), (|>>),
sequenceT, sequenceT_, mapT, mapT_,
Dynamic, persistentSQLite, closeDBHandles,
existsDBKey,
allDBKeys, allDBInfos, allDBKeyInfos,
ColVal, (@=), someDBKeys, someDBInfos, someDBKeyInfos, someDBKeyProjections,
getDBInfo, getDBInfos,
deleteDBEntry, deleteDBEntries, updateDBEntry, newDBEntry, newDBKeyEntry,
cleanDB
) where
import Global ( Global, GlobalSpec(..), global, readGlobal, writeGlobal )
import IO ( Handle, hPutStrLn, hGetLine, hFlush, hClose, stderr )
import IOExts ( connectToCommand )
import List ( intersperse, insertBy )
import Maybe ( mapMMaybe )
import ReadNumeric ( readInt )
import ReadShowTerm ( readQTerm, showQTerm, readsQTerm )
import System ( system )
infixl 1 |>>, |>>=
path'to'sqlite3 :: String
path'to'sqlite3 = "sqlite3"
data Query a = Query (IO a)
runQ :: Query a -> IO a
runQ (Query a) = a
transformQ :: (a -> b) -> Query a -> Query b
transformQ f query = Query (runQ query >>= return . f)
data Transaction a = Trans (IO (TransResult a))
data TransResult a = OK a | Error TError
unTrans :: Transaction a -> IO (TransResult a)
unTrans (Trans action) = action
runT :: Transaction a -> IO (Either a TError)
runT trans =
do beginTransaction
result <- catchTrans $ unTrans trans
case result of
Error err ->
do rollbackTransaction
return (Right err)
OK res ->
do commitTransaction
return (Left res)
catchTrans :: IO (TransResult a) -> IO (TransResult a)
catchTrans action =
action `catch` \terr ->
do err <- readGlobal lastQueryError
writeGlobal lastQueryError Nothing
return . Error $ maybe (TError ExecutionError (showError terr)) id err
runJustT :: Transaction a -> IO a
runJustT t =
runT t >>=
return . either id
(\e -> error ("Transaction failed: " ++ showTError e))
getDB :: Query a -> Transaction a
getDB query = Trans . catchTrans $ runQ query >>= return . OK
transIO :: IO a -> Transaction a
transIO action = Trans (action >>= return . OK)
returnT :: a -> Transaction a
returnT = transIO . return
doneT :: Transaction ()
doneT = transIO done
errorT :: TError -> Transaction a
errorT = Trans . return . Error
failT :: String -> Transaction a
failT = errorT . TError UserDefinedError
(|>>=) :: Transaction a -> (a -> Transaction b) -> Transaction b
Trans action |>>= f = Trans $
do result <- action
case result of
Error err -> return $ Error err
OK res -> unTrans $ f res
(|>>) :: Transaction _ -> Transaction a -> Transaction a
t1 |>> t2 = t1 |>>= const t2
sequenceT :: [Transaction a] -> Transaction [a]
sequenceT = foldr seqT (returnT [])
where
seqT t ts = t |>>= \x -> ts |>>= \xs -> returnT (x:xs)
sequenceT_ :: [Transaction _] -> Transaction ()
sequenceT_ = foldr (|>>) doneT
mapT :: (a -> Transaction b) -> [a] -> Transaction [b]
mapT f = sequenceT . map f
mapT_ :: (a -> Transaction _) -> [a] -> Transaction ()
mapT_ f = sequenceT_ . map f
type DBFile = String
type TableName = String
type ColName = String
data Dynamic = DBInfo DBFile TableName [ColName]
type Key = Int
type KeyPred a = Key -> a -> Dynamic
dbInfo :: KeyPred a -> (DBFile,(TableName,[ColName]))
dbInfo keyPred = (db,(table,cols))
where
DBInfo db table cols = keyPred ignored ignored
ignored :: a
ignored = error "unexpected access to argument of database predicate"
dbFile :: KeyPred _ -> DBFile
dbFile = fst . dbInfo
tableName :: KeyPred _ -> TableName
tableName = fst . snd . dbInfo
colNames :: KeyPred _ -> [ColName]
colNames = snd . snd . dbInfo
persistentSQLite :: DBFile -> TableName -> [ColName] -> KeyPred a
persistentSQLite db table cols _ _
| null cols = DBInfo db table ["info"]
| "_rowid_" `elem` cols = error "columns must not be called _rowid_"
| otherwise = DBInfo db table cols
existsDBKey :: KeyPred _ -> Key -> Query Bool
existsDBKey keyPred key = Query $
do n <- selectInt keyPred "count(*)" $ "where _rowid_ = " ++ show key
return $! n > 0
allDBKeys :: KeyPred _ -> Query [Key]
allDBKeys keyPred = Query $
do rows <- selectRows keyPred "_rowid_" ""
mapIO readIntOrExit rows
allDBInfos :: KeyPred a -> Query [a]
allDBInfos keyPred = Query $
do rows <- selectRows keyPred "*" ""
return $!! map readInfo rows
readInfo :: String -> a
readInfo str = readQTerm $ "(" ++ str ++ ")"
allDBKeyInfos :: KeyPred a -> Query [(Key,a)]
allDBKeyInfos keyPred = Query $
do rows <- selectRows keyPred "_rowid_,*" ""
mapIO readKeyInfo rows
readKeyInfo :: String -> IO (Key,a)
readKeyInfo row =
do key <- readIntOrExit keyStr
return $!! (key, readInfo infoStr)
where
(keyStr,_:infoStr) = break (','==) row
data ColVal = ColVal Int String
(@=) :: Int -> a -> ColVal
n @= x = ColVal n . quote $ showQTerm x
someDBKeys :: KeyPred _ -> [ColVal] -> Query [Key]
someDBKeys keyPred cvs = Query $
do rows <- selectSomeRows keyPred cvs "_rowid_"
mapIO readIntOrExit rows
someDBInfos :: KeyPred a -> [ColVal] -> Query [a]
someDBInfos keyPred cvs = Query $
do rows <- selectSomeRows keyPred cvs "*"
return $!! map readInfo rows
someDBKeyInfos :: KeyPred a -> [ColVal] -> Query [(Key,a)]
someDBKeyInfos keyPred cvs = Query $
do rows <- selectSomeRows keyPred cvs "_rowid_,*"
mapIO readKeyInfo rows
someDBKeyProjections :: KeyPred a -> [Int] -> [ColVal] -> Query [(Key,b)]
someDBKeyProjections keyPred cols cvs = Query $
do let colnames = commaSep (map ((colNames keyPred) !!) cols)
rows <- selectSomeRows keyPred cvs ("_rowid_,"++colnames)
mapIO readKeyInfo rows
getDBInfo :: KeyPred a -> Key -> Query (Maybe a)
getDBInfo keyPred key = Query $
do rows <- selectRows keyPred "*" $ "where _rowid_ = " ++ show key
readHeadIfExists rows
where
readHeadIfExists [] = return Nothing
readHeadIfExists (x:_) = return $!! Just (readInfo x)
getDBInfos :: KeyPred a -> [Key] -> Query (Maybe [a])
getDBInfos keyPred keys = Query $
do rows <- selectRows keyPred "_rowid_,*" $
"where _rowid_ in (" ++ commaSep (map show keys) ++ ")"
sortByIndexInGivenList rows
where
sortByIndexInGivenList rows =
do keyInfos <- mapIO readKeyInfo rows
return $ mapMMaybe (\key -> lookup key keyInfos) keys
commaSep :: [String] -> String
commaSep = concat . intersperse ", "
deleteDBEntry :: KeyPred _ -> Key -> Transaction ()
deleteDBEntry keyPred key =
modify keyPred "delete from" $ "where _rowid_ = " ++ show key
deleteDBEntries :: KeyPred _ -> [Key] -> Transaction ()
deleteDBEntries keyPred keys =
modify keyPred "delete from" $
"where _rowid_ in (" ++ commaSep (map show keys) ++ ")"
updateDBEntry :: KeyPred a -> Key -> a -> Transaction ()
updateDBEntry keyPred key info =
errorUnlessKeyExists keyPred key ("updateDBEntry, " ++ show key) |>>
modify keyPred "update"
("set " ++ commaSep (colVals keyPred info) ++
" where _rowid_ = " ++ show key)
errorUnlessKeyExists :: KeyPred a -> Key -> String -> Transaction ()
errorUnlessKeyExists keyPred key msg =
getDB (existsDBKey keyPred key) |>>= \exists ->
if not exists
then errorT $ TError KeyNotExistsError msg
else doneT
colVals :: KeyPred a -> a -> [String]
colVals keyPred info =
zipWith (\c v -> c ++ " = " ++ v) (colNames keyPred) (infoVals keyPred info)
infoVals :: KeyPred a -> a -> [String]
infoVals keyPred info
| null . tail $ colNames keyPred = [quote $ showQTerm info]
| otherwise = map quote $ showTupleArgs info
quote :: String -> String
quote s = "'" ++ concatMap quoteChar s ++ "'"
where
quoteChar c = if c == '\''then "''" else [c]
newDBEntry :: KeyPred a -> a -> Transaction Key
newDBEntry keyPred info =
modify keyPred "insert into"
("values (" ++ commaSep (infoVals keyPred info) ++ ")") |>>
getDB (Query $ selectInt keyPred "last_insert_rowid()" "")
newDBKeyEntry :: KeyPred a -> Key -> a -> Transaction ()
newDBKeyEntry keyPred key info =
getDB (existsDBKey keyPred key) |>>= \b ->
if b
then errorT . TError DuplicateKeyError $
"database already contains entry with key: " ++ show key
else modify keyPred "insert into"
("values (" ++ commaSep (infoVals keyPred info) ++ ")") |>>
getDB (Query $ selectInt keyPred "last_insert_rowid()" "") |>>= \k ->
modify keyPred "update" $
"set _rowid_ = " ++ show key ++ " where _rowid_ = " ++ show k
cleanDB :: KeyPred _ -> Transaction ()
cleanDB keyPred = modify keyPred "delete from" ""
sqlite3 :: KeyPred _ -> String -> IO Handle
sqlite3 keyPred sql =
do h <- getDBHandle keyPred
hPutAndFlush h $ sql ++ ";"
return h
hPutAndFlush :: Handle -> String -> IO ()
hPutAndFlush h s = hPutStrLn h s >> hFlush h
modify :: KeyPred _ -> String -> String -> Transaction ()
modify keyPred before after = transIO $
do sqlite3 keyPred $
before ++ " " ++ tableName keyPred ++ " " ++ after
done
selectInt :: KeyPred _ -> String -> String -> IO Int
selectInt keyPred aggr cond =
do h <- sqlite3 keyPred $
"select distinct " ++ aggr ++
" from " ++ tableName keyPred ++ " " ++ cond
hGetLine h >>= readIntOrExit
readIntOrExit :: String -> IO Int
readIntOrExit s = maybe err (return . fst) $ readInt s
where
err = dbError ExecutionError $
"readIntOrExit: cannot parse integer from string '" ++ show s ++ "'"
type Row = String
selectRows :: KeyPred _ -> String -> String -> IO [Row]
selectRows keyPred cols cond =
do h <- sqlite3 keyPred "select hex(randomblob(8))"
rnd <- hGetLine h
hPutAndFlush h $
"select " ++ cols ++ " from " ++ tableName keyPred ++
" " ++ cond ++ "; select " ++ quote rnd ++ ";"
hGetLinesBefore h rnd
hGetLinesBefore :: Handle -> String -> IO [String]
hGetLinesBefore h stop =
do line <- hGetLine h
if line == stop
then return []
else do rest <- hGetLinesBefore h stop
return (line : rest)
selectSomeRows :: KeyPred _ -> [ColVal] -> String -> IO [Row]
selectSomeRows keyPred cvs cols =
selectRows keyPred cols $ if null cvs then ""
else "where " ++ showColVals keyPred cvs
showColVals :: KeyPred a -> [ColVal] -> String
showColVals _ [] = "1"
showColVals keyPred (c:vs) = concat . intersperse " AND " $ map showCV (c:vs)
where
showCV (ColVal n s) = colNames keyPred !! n ++ " = " ++ s
closeDBHandles :: IO ()
closeDBHandles =
do withAllDBHandles hClose
writeGlobal openDBHandles []
dbError :: TErrorKind -> String -> IO a
dbError kind msg =
do writeGlobal lastQueryError . Just $ TError kind msg
error msg
lastQueryError :: Global (Maybe TError)
lastQueryError = global Nothing Temporary
getDBHandle :: KeyPred _ -> IO Handle
getDBHandle keyPred =
do ensureDBFor keyPred
readDBHandle $ dbFile keyPred
ensureDBFor :: KeyPred _ -> IO ()
ensureDBFor keyPred =
do ensureDBHandle db
ensureDBTable db table cols
where
(db,(table,cols)) = dbInfo keyPred
readDBHandle :: DBFile -> IO Handle
readDBHandle db = readGlobal openDBHandles >>= maybe err return . lookup db
where
err = dbError ExecutionError $ "readDBHandle: no handle for '" ++ db ++ "'"
openDBHandles :: Global [(DBFile,Handle)]
openDBHandles = global [] Temporary
withAllDBHandles :: (Handle -> IO _) -> IO ()
withAllDBHandles f =
do dbHandles <- readGlobal openDBHandles
mapIO_ (f . snd) dbHandles
ensureDBHandle :: DBFile -> IO ()
ensureDBHandle db =
do dbHandles <- readGlobal openDBHandles
unless (db `elem` map fst dbHandles) $ addNewDBHandle dbHandles
where
addNewDBHandle dbHandles = do
exsqlite3 <- system $ "which " ++ path'to'sqlite3 ++ " > /dev/null"
when (exsqlite3>0) $
error "Database interface `sqlite3' not found. Please install package `sqlite3'!"
h <- connectToCommand $ path'to'sqlite3 ++ " " ++ db
hPutAndFlush h ".separator ','"
writeGlobal openDBHandles $
insertBy ((<=) `on` fst) (db,h) dbHandles
isTrans <- readGlobal currentlyInTransaction
unless (not isTrans) $ hPutStrLn h "begin immediate;"
unless :: Bool -> IO () -> IO ()
unless False action = action
unless True _ = done
on :: (b -> b -> c) -> (a -> b) -> a -> a -> c
on f g x y = f (g x) (g y)
ensureDBTable :: DBFile -> TableName -> [ColName] -> IO ()
ensureDBTable db table cols =
do dbTables <- readGlobal knownDBTables
unless ((db,table) `elem` dbTables) $
do h <- readDBHandle db
hPutAndFlush h $
"create table if not exists " ++ table ++
" (" ++ commaSep cols ++ ");"
writeGlobal knownDBTables $ (db,table) : dbTables
knownDBTables :: Global [(DBFile,TableName)]
knownDBTables = global [] Temporary
beginTransaction :: IO ()
beginTransaction =
do writeGlobal currentlyInTransaction True
withAllDBHandles (`hPutAndFlush` "begin immediate;")
commitTransaction :: IO ()
commitTransaction =
do withAllDBHandles (`hPutAndFlush` "commit;")
writeGlobal currentlyInTransaction False
rollbackTransaction :: IO ()
rollbackTransaction =
do withAllDBHandles (`hPutAndFlush` "rollback;")
writeGlobal currentlyInTransaction False
currentlyInTransaction :: Global Bool
currentlyInTransaction = global False Temporary
showTupleArgs :: a -> [String]
showTupleArgs = splitTLC . removeOuterParens . showQTerm
removeOuterParens :: String -> String
removeOuterParens ('(':cs) = init cs
init :: [a] -> [a]
init = reverse . tail . reverse
splitTLC :: String -> [String]
splitTLC = parse ""
type Stack = String
parse :: Stack -> String -> [String]
parse _ "" = []
parse st (c:cs) =
case (st,c:cs) of
('\'':xs,'\'':'\'':ys) -> '\'' <: ('\'' <: parse xs ys)
_ -> next c st $ parse (updStack c st) cs
next :: Char -> Stack -> [String] -> [String]
next c [] xs = if c==',' then [] : xs else c <: xs
next c (_:_) xs = c <: xs
(<:) :: Char -> [String] -> [String]
c <: [] = [[c]]
c <: (x:xs) = (c:x):xs
updStack :: Char -> Stack -> Stack
updStack char stack =
case (char,stack) of
(_ ,'\\':xs) -> xs
('\\', xs) -> '\\':xs
('"' , '"':xs) -> xs
('"' , '\'':xs)-> '\'':xs
('"' , xs) -> '"':xs
('\'', '\'':xs)-> xs
('\'', '"':xs) -> '"':xs
('\'', xs) -> '\'':xs
(_ , '"':xs) -> '"':xs
(_ , '\'':xs)-> '\'':xs
('(' , xs) -> '(':xs
(')' , '(':xs) -> xs
('[' , xs) -> '[':xs
(']' , '[':xs) -> xs
(_ , xs) -> xs
data TError = TError TErrorKind String
data TErrorKind = KeyNotExistsError
| NoRelationshipError
| DuplicateKeyError
| KeyRequiredError
| UniqueError
| MinError
| MaxError
| UserDefinedError
| ExecutionError
showTError :: TError -> String
showTError (TError k s) = "Transaction error " ++ show k ++ ": " ++ s
|