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{- arch-tag: Python low-level utilities
Copyright (C) 2005 John Goerzen <jgoerzen@complete.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-}
{- |
Module : Python.Utils
Copyright : Copyright (C) 2005 John Goerzen
License : GNU GPL, version 2 or above
Maintainer : John Goerzen,
Maintainer : jgoerzen\@complete.org
Stability : provisional
Portability: portable
Python low-level utilities
Written by John Goerzen, jgoerzen\@complete.org
Please use sparingly and with caution. The documentation for their behavior
should be considered to be the source code.
-}
module Python.Utils (-- * Objects
fromCPyObject,
withPyObject,
maybeWithPyObject,
-- * Exceptions
raisePyException,
checkCInt,
-- * Environment
getDefaultGlobals,
pyImport_AddModule,
pyModule_GetDict,
py_incref
)
where
import Python.Types
import Python.ForeignImports
import Foreign.C.Types
import Foreign.C
import Foreign
import Foreign.Ptr
import Foreign.Marshal.Array
import Foreign.Marshal.Alloc
import Control.Exception
{- | Convert a Ptr 'CPyObject' to a 'PyObject'. -}
fromCPyObject :: Ptr CPyObject -> IO PyObject
fromCPyObject po =
if po == nullPtr
then raisePyException
else do fp <- newForeignPtr py_decref po
return $ PyObject fp
{- | Called to make sure the passed CInt isn't -1. Raise an exception if
it is. -}
checkCInt :: CInt -> IO CInt
checkCInt x =
if x == (-1)
then raisePyException
else return x
{- | Called when a Python exception has been detected. It will raise
the exception in Haskell. -}
raisePyException :: IO a
raisePyException =
let noneorptr cval = if cval == nullPtr
then do p <- cNone
fromCPyObject p
else fromCPyObject cval
in alloca (\typeptr -> alloca (\valptr -> alloca (\tbptr ->
do pyErr_Fetch typeptr valptr tbptr
pyErr_NormalizeException typeptr valptr tbptr
ctype <- peek typeptr
cval <- peek valptr
ctb <- peek tbptr
otype <- noneorptr ctype
oval <- noneorptr cval
otb <- noneorptr ctb
--seq otype $ return ()
--seq oval $ return ()
--seq otb $ return ()
let exc = PyException {excType = otype, excValue = oval,
excTraceBack = otb,
excFormatted = ""}
pyErr_Clear
throwDyn exc
)))
{-
do cpy <- getexc
let (exc, val, tb) = cpy
--pyErr_Print
fail "Python Error!"
where getexc = do cexc <- hspy_getexc
exc <- peekArray 3 cexc
exc2 <- mapM fromCPyObject exc
case exc2 of
[x, y, z] -> return (x, y, z)
_ -> fail "Got unexpected number of elements"
-}
{- | Uses a 'PyObject' in a function that needs Ptr 'CPyObject'. -}
withPyObject :: PyObject -> (Ptr CPyObject -> IO b) -> IO b
withPyObject (PyObject x) = withForeignPtr x
{- | Same as 'withPyObject', but uses nullPtr if the input is Nothing. -}
maybeWithPyObject :: Maybe PyObject -> (Ptr CPyObject -> IO b) -> IO b
maybeWithPyObject Nothing func = func nullPtr
maybeWithPyObject (Just x) y = withPyObject x y
{- | Returns the default globals environment. -}
getDefaultGlobals :: IO PyObject
getDefaultGlobals =
do m <- pyImport_AddModule "__main__"
pyModule_GetDict m
{- | Wrapper around C PyImport_AddModule, which looks up an existing module -}
pyImport_AddModule :: String -> IO PyObject
pyImport_AddModule x =
withCString x (\cstr ->
do r <- cpyImport_AddModule cstr
py_incref r
fromCPyObject r
)
{- | Gets the dict associated with a module. -}
pyModule_GetDict :: PyObject -> IO PyObject
pyModule_GetDict x =
withPyObject x (\cpyo ->
do r <- cpyModule_GetDict cpyo
py_incref r
fromCPyObject r)
|
