HDBC-postgresql-1.1.4.0: Database/HDBC/PostgreSQL/Statement.hs
{-# OPTIONS_GHC -optc-D__HUGS__ #-}
{-# INCLUDE <libpq-fe.h> #-}
{-# LINE 1 "Database/HDBC/PostgreSQL/Statement.hsc" #-}
-- -*- mode: haskell; -*-
{-# LINE 2 "Database/HDBC/PostgreSQL/Statement.hsc" #-}
{-# CFILES hdbc-postgresql-helper.c #-}
-- Above line for hugs
{-
Copyright (C) 2005 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 Foreign.Marshal
import Foreign.Storable
import Control.Monad
import Data.List
import Data.Word
import Data.Maybe
import Data.Ratio
import Control.Exception
import System.IO
import System.Time
import Database.HDBC.PostgreSQL.Parser(convertSQL)
import Database.HDBC.DriverUtils
import Database.HDBC.PostgreSQL.PTypeConv
l _ = return ()
--l m = hPutStrLn stderr ("\n" ++ m)
{-# LINE 49 "Database/HDBC/PostgreSQL/Statement.hsc" #-}
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 -> throwDyn $ 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,
finish = public_ffinish sstate,
fetchRow = ffetchrow sstate,
originalQuery = query,
getColumnNames = fgetColumnNames sstate,
describeResult = fdescribeResult sstate}
addChild mchildren retval
return retval
fgetColumnNames sstate =
do c <- readMVar (coldefmv sstate)
return (map fst c)
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 sstate args = withConn (dbo sstate) $ \cconn ->
withCString (squery sstate) $ \cquery ->
withCStringArr0 args $ \cargs ->
do l "in fexecute"
public_ffinish sstate -- Sets nextrowmv to -1
resptr <- pqexecParams cconn cquery
(genericLength args) nullPtr cargs nullPtr nullPtr 0
status <- pqresultStatus resptr
case status of
0 ->
{-# LINE 105 "Database/HDBC/PostgreSQL/Statement.hsc" #-}
do l $ "PGRES_EMPTY_QUERY: " ++ squery sstate
pqclear_raw resptr
swapMVar (coldefmv sstate) []
return 0
1 ->
{-# LINE 110 "Database/HDBC/PostgreSQL/Statement.hsc" #-}
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
2 ->
{-# LINE 119 "Database/HDBC/PostgreSQL/Statement.hsc" #-}
do l $ "PGRES_TUPLES_OK: " ++ squery sstate
fgetcoldef resptr >>= swapMVar (coldefmv sstate)
numrows <- pqntuples resptr
if numrows < 1
then do 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
statusmsg <- peekCString csstatusmsg
errormsg <- peekCString cserrormsg
pqclear_raw resptr
throwDyn $
SqlError {seState = "",
seNativeError = fromIntegral status,
seErrorMsg = "execute: " ++ statusmsg ++
": " ++ errormsg}
{- 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 <- peekCString text
makeSqlValue coltype s
fgetcoldef cstmt =
do ncols <- pqnfields cstmt
mapM desccol [0..(ncols - 1)]
where desccol i =
do colname <- (pqfname cstmt i >>= peekCString)
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 =
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 Word32
{-# LINE 204 "Database/HDBC/PostgreSQL/Statement.hsc" #-}
foreign import ccall unsafe "libpq-fe.h PQexecParams"
pqexecParams :: (Ptr CConn) -> CString -> CInt ->
(Ptr Word32) ->
{-# LINE 208 "Database/HDBC/PostgreSQL/Statement.hsc" #-}
(Ptr CString) ->
(Ptr CInt) ->
(Ptr CInt) ->
CInt ->
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 :: Word32 -> IO CString
{-# LINE 230 "Database/HDBC/PostgreSQL/Statement.hsc" #-}
foreign import ccall unsafe "libpq-fe.h PQresultErrorMessage"
pqresultErrorMessage :: (Ptr CStmt) -> 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 Word32
{-# LINE 251 "Database/HDBC/PostgreSQL/Statement.hsc" #-}
-- 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 -> String -> IO SqlValue
makeSqlValue sqltypeid strval =
case sqltypeid of
tid | tid == SqlCharT ||
tid == SqlVarCharT ||
tid == SqlLongVarCharT ||
tid == SqlWCharT ||
tid == SqlWVarCharT ||
tid == SqlWLongVarCharT -> return $ SqlString strval
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 ||
tid == SqlTimestampT ||
tid == SqlUTCDateTimeT ->
do
clockTime <- clockTimeFromISODateAndMaybeTime strval
case clockTime of TOD epochSecs picos -> return $ SqlEpochTime epochSecs
-- Times without dates
tid | tid == SqlTimeT ||
tid == SqlUTCTimeT -> return $ SqlTimeDiff $ secsTimeDiffFromISOTime strval
-- TODO: There's no proper way to map intervals as understood by postgres currently so we resort to SqlString.
-- E.g. a "1 month" interval is not a specific span of time that could be converted to a SqlTimeDiff.
-- A new SqlValue constructor would be needed (wrapping System.Time.TimeDiff) to really handle intervals properly.
SqlIntervalT si -> return $ SqlString strval
-- TODO: For now we just map the binary types to SqlStrings. New SqlValue constructors are needed to handle these.
tid | tid == SqlBinaryT ||
tid == SqlVarBinaryT ||
tid == SqlLongVarBinaryT -> return $ SqlString strval
SqlGUIDT -> return $ SqlString strval
SqlUnknownT s -> return $ SqlString strval
-- 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
-- Creates a ClockTime from an ISO-8601 representation of a date or date/time with optional numeric timezone, as output by Postgres.
-- The IO monad is required because local timezone information may need to be fetched if not provided in the input string.
clockTimeFromISODateAndMaybeTime :: String -> IO ClockTime
clockTimeFromISODateAndMaybeTime datestr =
let
(y, '-':month_etc) = head $ reads datestr
(mo, '-':day_etc) = head $ reads month_etc
(d, maybeTime) = head $ reads day_etc
hourParses = reads maybeTime
(h, min_etc) = if not (null hourParses) then head hourParses else (0,"")
(min, sec_etc) = if not (null $ drop 1 min_etc) then head $ reads (drop 1 min_etc) else (0,"")
(sec, maybeTZ) = if not (null $ drop 1 sec_etc) then head $ reads (drop 1 sec_etc) else (0,"")
tzParses = reads maybeTZ
in
do
tzoff <- if not $ null tzParses then return $ 3600 * (fst $ head $ tzParses) else getLocalTimeZoneOffsetSecsForDateTime y mo d h min sec
if null hourParses
then
return $ toClockTime $ makeCalendarTimeForDate y mo d tzoff
else
return $ toClockTime $ makeCalendarTimeForDateTime y mo d h min sec tzoff
where
makeCalendarTimeForDate :: Int -> Int -> Int -> Int -> CalendarTime
makeCalendarTimeForDate year mon day tzoff =
CalendarTime { ctYear = year, ctMonth = makeMonth mon, ctDay = day,
ctHour = 0, ctMin = 0, ctSec = 0, ctPicosec = 0,
ctWDay = Sunday, ctYDay = 0, -- bogus but ignored when converting to ClockTime according to the docs in System.Time
ctTZName = "",
ctTZ = tzoff,
ctIsDST = False -- bogus but ignored when converting to ClockTime
}
makeCalendarTimeForDateTime :: Int -> Int -> Int -> Int -> Int -> Int -> Int -> CalendarTime
makeCalendarTimeForDateTime year mon day hour min sec tzoff =
CalendarTime { ctYear = year, ctMonth = makeMonth mon, ctDay = day, ctHour = hour, ctMin = min, ctSec = sec,
ctPicosec = 0,
ctWDay = Sunday, ctYDay = 0, -- bogus but ignored when converting to ClockTime
ctTZName = "",
ctTZ = tzoff,
ctIsDST = False -- bogus but ignored when converting to ClockTime
}
-- Convert 1->Jan, 2->Feb etc as commonly done on planet Earth (what's with the Month enum instance in System.Time ?)
makeMonth :: Int -> Month
makeMonth monNum = toEnum (monNum - 1)
getLocalTimeZoneOffsetSecsForDateTime :: Int -> Int -> Int -> Int -> Int -> Int -> IO Int
getLocalTimeZoneOffsetSecsForDateTime y mo d h min s =
do
-- Convert nominal day and time at GMT to our location to get first guess of our tz offset at required date and time
approxLocalCalTime <- toLocalCalTime (makeCalendarTimeForDateTime y mo d h min s 0)
-- First guess of the proper timezon offset for this date and time in our location.
let firstGuess = makeCalendarTimeForDateTime y mo d h min s (ctTZ approxLocalCalTime)
-- Allow up to 6 hours for date/time dependent timezone offset adjustments (Usually should be 0,1, or -1 depending on daylight savings time).
let adjustments = map (3600*) $ [0,-1,1] ++ [2..6] ++ [-2,-3..(-6)]
let adjustedCalTimes = map (\adj -> firstGuess { ctTZ = ctTZ firstGuess + adj }) adjustments
successList <- mapM isFixedPointUnderConversionToLocalTime adjustedCalTimes
case elemIndex True successList of
Nothing -> error $ "Could not find proper timezone for date: " ++
show y ++ "-" ++ show mo ++ "-" ++ show d ++ " " ++ show h ++ ":" ++ show min ++ ":" ++ show s
Just ix -> return (ctTZ $ adjustedCalTimes!!ix)
where
toLocalCalTime :: CalendarTime -> IO CalendarTime
toLocalCalTime calTime = toCalendarTime $ toClockTime calTime
isFixedPointUnderConversionToLocalTime :: CalendarTime -> IO Bool
isFixedPointUnderConversionToLocalTime calTime =
do
calTime' <- toLocalCalTime calTime
return $ eqParts calTime calTime'
eqParts :: CalendarTime -> CalendarTime -> Bool
eqParts calTime1 calTime2 = ctHour calTime1 == ctHour calTime2 &&
ctMin calTime1 == ctMin calTime2 &&
ctSec calTime1 == ctSec calTime2 &&
ctDay calTime1 == ctDay calTime2 &&
ctMonth calTime1 == ctMonth calTime2 &&
ctYear calTime1 == ctYear calTime2
-- Time values (without dates) are represented as a seconds count
secsTimeDiffFromISOTime :: String -> Integer
secsTimeDiffFromISOTime timestr =
let
(h, min_etc) = head $ reads timestr
(min, sec_etc) = if null min_etc || min_etc == ":" then (0,":0") else head $ reads (tail min_etc)
(sec, _) = if null sec_etc || sec_etc == ":" then (0,"") else head $ reads (tail sec_etc)
in
h * 3600 + 60 * min + sec