HDBC-postgresql-2.2.3.2: Database/HDBC/PostgreSQL/Statement.hsc
-- -*- mode: haskell; -*-
{-# CFILES hdbc-postgresql-helper.c #-}
-- Above line for hugs
{-
Copyright (C) 2005-2009 John Goerzen <jgoerzen@complete.org>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
-}
module Database.HDBC.PostgreSQL.Statement where
import Database.HDBC.Types
import Database.HDBC
import Database.HDBC.PostgreSQL.Types
import Database.HDBC.PostgreSQL.Utils
import Foreign.C.Types
import Foreign.ForeignPtr
import Foreign.Ptr
import Control.Concurrent.MVar
import Foreign.C.String
import Control.Monad
import Data.List
import Data.Word
import Data.Maybe
import Data.Ratio
import System.IO
import qualified Data.ByteString as B
import qualified Data.ByteString.UTF8 as BUTF8
import Database.HDBC.PostgreSQL.Parser(convertSQL)
import Database.HDBC.DriverUtils
import Database.HDBC.PostgreSQL.PTypeConv
import Database.HDBC.PostgreSQL.Utils
import Data.Time.Format
import System.Locale
l _ = return ()
--l m = hPutStrLn stderr ("\n" ++ m)
#include <libpq-fe.h>
data SState =
SState { stomv :: MVar (Maybe Stmt),
nextrowmv :: MVar (CInt), -- -1 for no next row (empty); otherwise, next row to read.
dbo :: Conn,
squery :: String,
coldefmv :: MVar [(String, SqlColDesc)]}
-- FIXME: we currently do no prepare optimization whatsoever.
newSth :: Conn -> ChildList -> String -> IO Statement
newSth indbo mchildren query =
do l "in newSth"
newstomv <- newMVar Nothing
newnextrowmv <- newMVar (-1)
newcoldefmv <- newMVar []
usequery <- case convertSQL query of
Left errstr -> throwSqlError $ SqlError
{seState = "",
seNativeError = (-1),
seErrorMsg = "hdbc prepare: " ++
show errstr}
Right converted -> return converted
let sstate = SState {stomv = newstomv, nextrowmv = newnextrowmv,
dbo = indbo, squery = usequery,
coldefmv = newcoldefmv}
let retval =
Statement {execute = fexecute sstate,
executeMany = fexecutemany sstate,
executeRaw = fexecuteRaw sstate,
finish = public_ffinish sstate,
fetchRow = ffetchrow sstate,
originalQuery = query,
getColumnNames = fgetColumnNames sstate,
describeResult = fdescribeResult sstate}
addChild mchildren retval
return retval
fgetColumnNames :: SState -> IO [(String)]
fgetColumnNames sstate =
do c <- readMVar (coldefmv sstate)
return (map fst c)
fdescribeResult :: SState -> IO [(String, SqlColDesc)]
fdescribeResult sstate =
readMVar (coldefmv sstate)
{- For now, we try to just handle things as simply as possible.
FIXME lots of room for improvement here (types, etc). -}
fexecute :: (Num a, Read a) => SState -> [SqlValue] -> IO a
fexecute sstate args = withConnLocked (dbo sstate) $ \cconn ->
B.useAsCString (BUTF8.fromString (squery sstate)) $ \cquery ->
withCStringArr0 args $ \cargs -> -- wichSTringArr0 uses UTF-8
do l "in fexecute"
public_ffinish sstate -- Sets nextrowmv to -1
resptr <- pqexecParams cconn cquery
(genericLength args) nullPtr cargs nullPtr nullPtr 0
handleResultStatus resptr sstate =<< pqresultStatus resptr
{- | Differs from fexecute in that it does not prepare its input
query, and the input query may contain multiple statements. This
is useful for issuing DDL or DML commands. -}
fexecuteRaw :: SState -> IO ()
fexecuteRaw sstate =
withConnLocked (dbo sstate) $ \cconn ->
B.useAsCString (BUTF8.fromString (squery sstate)) $ \cquery ->
do l "in fexecute"
public_ffinish sstate -- Sets nextrowmv to -1
resptr <- pqexec cconn cquery
handleResultStatus resptr sstate =<< pqresultStatus resptr
return ()
handleResultStatus :: (Num a, Read a) => WrappedCStmt -> SState -> ResultStatus -> IO a
handleResultStatus resptr sstate status =
case status of
#{const PGRES_EMPTY_QUERY} ->
do l $ "PGRES_EMPTY_QUERY: " ++ squery sstate
pqclear_raw resptr
swapMVar (coldefmv sstate) []
return 0
#{const PGRES_COMMAND_OK} ->
do l $ "PGRES_COMMAND_OK: " ++ squery sstate
rowscs <- pqcmdTuples resptr
rows <- peekCString rowscs
pqclear_raw resptr
swapMVar (coldefmv sstate) []
return $ case rows of
"" -> 0
x -> read x
#{const PGRES_TUPLES_OK} ->
do l $ "PGRES_TUPLES_OK: " ++ squery sstate
fgetcoldef resptr >>= swapMVar (coldefmv sstate)
numrows <- pqntuples resptr
if numrows < 1 then (pqclear_raw resptr >> return 0) else
do
wrappedptr <- withRawConn (dbo sstate)
(\rawconn -> wrapstmt resptr rawconn)
fresptr <- newForeignPtr pqclearptr wrappedptr
swapMVar (nextrowmv sstate) 0
swapMVar (stomv sstate) (Just fresptr)
return 0
_ -> do l $ "PGRES ERROR: " ++ squery sstate
csstatusmsg <- pqresStatus status
cserrormsg <- pqresultErrorMessage resptr
statusmsgbs <- B.packCString csstatusmsg
errormsgbs <- B.packCString cserrormsg
let statusmsg = BUTF8.toString statusmsgbs
let errormsg = BUTF8.toString errormsgbs
state <- pqresultErrorField resptr #{const PG_DIAG_SQLSTATE} >>= peekCStringUTF8
pqclear_raw resptr
throwSqlError $ SqlError { seState = state
, seNativeError = fromIntegral status
, seErrorMsg = "execute: " ++ statusmsg ++
": " ++ errormsg}
peekCStringUTF8 :: CString -> IO String
-- Marshal a NUL terminated C string into a Haskell string, decoding it
-- with UTF8.
peekCStringUTF8 str = fmap BUTF8.toString (B.packCString str)
{- General algorithm: find out how many columns we have, check the type
of each to see if it's NULL. If it's not, fetch it as text and return that.
-}
ffetchrow :: SState -> IO (Maybe [SqlValue])
ffetchrow sstate = modifyMVar (nextrowmv sstate) dofetchrow
where dofetchrow (-1) = l "ffr -1" >> return ((-1), Nothing)
dofetchrow nextrow = modifyMVar (stomv sstate) $ \stmt ->
case stmt of
Nothing -> l "ffr nos" >> return (stmt, ((-1), Nothing))
Just cmstmt -> withStmt cmstmt $ \cstmt ->
do l $ "ffetchrow: " ++ show nextrow
numrows <- pqntuples cstmt
l $ "numrows: " ++ show numrows
if nextrow >= numrows
then do l "no more rows"
-- Don't use public_ffinish here
ffinish cmstmt
return (Nothing, ((-1), Nothing))
else do l "getting stuff"
ncols <- pqnfields cstmt
res <- mapM (getCol cstmt nextrow)
[0..(ncols - 1)]
return (stmt, (nextrow + 1, Just res))
getCol p row icol =
do isnull <- pqgetisnull p row icol
if isnull /= 0
then return SqlNull
else do text <- pqgetvalue p row icol
coltype <- liftM oidToColType $ pqftype p icol
s <- B.packCString text
makeSqlValue coltype s
fgetcoldef :: Ptr CStmt -> IO [(String, SqlColDesc)]
fgetcoldef cstmt =
do ncols <- pqnfields cstmt
mapM desccol [0..(ncols - 1)]
where desccol i =
do colname <- (pqfname cstmt i >>= B.packCString >>=
return . BUTF8.toString)
coltype <- pqftype cstmt i
--coloctets <- pqfsize
let coldef = oidToColDef coltype
return (colname, coldef)
-- FIXME: needs a faster algorithm.
fexecutemany :: SState -> [[SqlValue]] -> IO ()
fexecutemany sstate arglist =
mapM_ (fexecute sstate) arglist >> return ()
-- Finish and change state
public_ffinish :: SState -> IO ()
public_ffinish sstate =
do l "public_ffinish"
swapMVar (nextrowmv sstate) (-1)
modifyMVar_ (stomv sstate) worker
where worker Nothing = return Nothing
worker (Just sth) = ffinish sth >> return Nothing
ffinish :: Stmt -> IO ()
ffinish p = withRawStmt p $ pqclear
foreign import ccall unsafe "libpq-fe.h PQresultStatus"
pqresultStatus :: (Ptr CStmt) -> IO #{type ExecStatusType}
foreign import ccall safe "libpq-fe.h PQexecParams"
pqexecParams :: (Ptr CConn) -> CString -> CInt ->
(Ptr #{type Oid}) ->
(Ptr CString) ->
(Ptr CInt) ->
(Ptr CInt) ->
CInt ->
IO (Ptr CStmt)
foreign import ccall safe "libpq-fe.h PQexec"
pqexec :: (Ptr CConn) -> CString -> IO (Ptr CStmt)
foreign import ccall unsafe "hdbc-postgresql-helper.h PQclear_app"
pqclear :: Ptr WrappedCStmt -> IO ()
foreign import ccall unsafe "hdbc-postgresql-helper.h &PQclear_finalizer"
pqclearptr :: FunPtr (Ptr WrappedCStmt -> IO ())
foreign import ccall unsafe "libpq-fe.h PQclear"
pqclear_raw :: Ptr CStmt -> IO ()
foreign import ccall unsafe "hdbc-postgresql-helper.h wrapobjpg"
wrapstmt :: Ptr CStmt -> Ptr WrappedCConn -> IO (Ptr WrappedCStmt)
foreign import ccall unsafe "libpq-fe.h PQcmdTuples"
pqcmdTuples :: Ptr CStmt -> IO CString
foreign import ccall unsafe "libpq-fe.h PQresStatus"
pqresStatus :: #{type ExecStatusType} -> IO CString
foreign import ccall unsafe "libpq-fe.h PQresultErrorMessage"
pqresultErrorMessage :: (Ptr CStmt) -> IO CString
foreign import ccall unsafe "libpq-fe.h PQresultErrorField"
pqresultErrorField :: (Ptr CStmt) -> CInt -> IO CString
foreign import ccall unsafe "libpq-fe.h PQntuples"
pqntuples :: Ptr CStmt -> IO CInt
foreign import ccall unsafe "libpq-fe.h PQnfields"
pqnfields :: Ptr CStmt -> IO CInt
foreign import ccall unsafe "libpq-fe.h PQgetisnull"
pqgetisnull :: Ptr CStmt -> CInt -> CInt -> IO CInt
foreign import ccall unsafe "libpq-fe.h PQgetvalue"
pqgetvalue :: Ptr CStmt -> CInt -> CInt -> IO CString
foreign import ccall unsafe "libpq-fe.h PQfname"
pqfname :: Ptr CStmt -> CInt -> IO CString
foreign import ccall unsafe "libpq-fe.h PQftype"
pqftype :: Ptr CStmt -> CInt -> IO #{type Oid}
-- SqlValue construction function and helpers
-- Make a SqlValue for the passed column type and string value, where it is assumed that the value represented is not the Sql null value.
-- The IO Monad is required only to obtain the local timezone for interpreting date/time values without an explicit timezone.
makeSqlValue :: SqlTypeId -> B.ByteString -> IO SqlValue
makeSqlValue sqltypeid bstrval =
let strval = BUTF8.toString bstrval
in
case sqltypeid of
tid | tid == SqlCharT ||
tid == SqlVarCharT ||
tid == SqlLongVarCharT ||
tid == SqlWCharT ||
tid == SqlWVarCharT ||
tid == SqlWLongVarCharT -> return $ SqlByteString bstrval
tid | tid == SqlDecimalT ||
tid == SqlNumericT -> return $ SqlRational (makeRationalFromDecimal strval)
tid | tid == SqlSmallIntT ||
tid == SqlTinyIntT ||
tid == SqlIntegerT -> return $ SqlInt32 (read strval)
SqlBigIntT -> return $ SqlInteger (read strval)
tid | tid == SqlRealT ||
tid == SqlFloatT ||
tid == SqlDoubleT -> return $ SqlDouble (read strval)
SqlBitT -> return $ case strval of
't':_ -> SqlBool True
'f':_ -> SqlBool False
'T':_ -> SqlBool True -- the rest of these are here "just in case", since they are legal as input
'y':_ -> SqlBool True
'Y':_ -> SqlBool True
"1" -> SqlBool True
_ -> SqlBool False
-- Dates and Date/Times
tid | tid == SqlDateT -> return $ SqlLocalDate (fromSql (toSql strval))
tid | tid == SqlTimestampWithZoneT -> return $ SqlZonedTime (fromSql (toSql (fixString strval)))
-- SqlUTCDateTimeT not actually generated by PostgreSQL
tid | tid == SqlTimestampT ||
tid == SqlUTCDateTimeT -> return $ SqlLocalTime (fromSql (toSql strval))
-- Times without dates
tid | tid == SqlTimeT ||
tid == SqlUTCTimeT -> return $ SqlLocalTimeOfDay (fromSql (toSql strval))
tid | tid == SqlTimeWithZoneT ->
(let (a, b) = case (parseTime defaultTimeLocale "%T%Q %z" timestr,
parseTime defaultTimeLocale "%T%Q %z" timestr) of
(Just x, Just y) -> (x, y)
x -> error $ "PostgreSQL Statement.hsc: Couldn't parse " ++ strval ++ " as SqlZonedLocalTimeOfDay: " ++ show x
timestr = fixString strval
in return $ SqlZonedLocalTimeOfDay a b)
SqlIntervalT _ -> return $ SqlDiffTime $ fromRational $
case split ':' strval of
[h, m, s] -> toRational (((read h)::Integer) * 60 * 60 +
((read m)::Integer) * 60) +
toRational ((read s)::Double)
_ -> error $ "PostgreSQL Statement.hsc: Couldn't parse interval: " ++ strval
-- TODO: For now we just map the binary types to SqlByteStrings. New SqlValue constructors are needed to handle these.
tid | tid == SqlBinaryT ||
tid == SqlVarBinaryT ||
tid == SqlLongVarBinaryT -> return $ SqlByteString bstrval
SqlGUIDT -> return $ SqlByteString bstrval
SqlUnknownT _ -> return $ SqlByteString bstrval
-- Convert "15:33:01.536+00" to "15:33:01.536 +0000"
fixString :: String -> String
fixString s =
let (strbase, zone) = splitAt (length s - 3) s
in
if (head zone) == '-' || (head zone) == '+'
then strbase ++ " " ++ zone ++ "00"
else -- It wasn't in the expected format; don't touch.
s
-- Make a rational number from a decimal string representation of the number.
makeRationalFromDecimal :: String -> Rational
makeRationalFromDecimal s =
case elemIndex '.' s of
Nothing -> toRational ((read s)::Integer)
Just dotix ->
let (nstr,'.':dstr) = splitAt dotix s
num = (read $ nstr ++ dstr)::Integer
den = 10^((genericLength dstr) :: Integer)
in
num % den
split :: Char -> String -> [String]
split delim inp =
lines . map (\x -> if x == delim then '\n' else x) $ inp