path: root/src/pl/plpython/plpython.c

/**********************************************************************
 * plpython.c - python as a procedural language for PostgreSQL
 *
 * This software is copyright by Andrew Bosma
 * but is really shameless cribbed from pltcl.c by Jan Weick, and
 * plperl.c by Mark Hollomon.
 *
 * The author hereby grants permission to use, copy, modify,
 * distribute, and license this software and its documentation for any
 * purpose, provided that existing copyright notices are retained in
 * all copies and that this notice is included verbatim in any
 * distributions. No written agreement, license, or royalty fee is
 * required for any of the authorized uses.  Modifications to this
 * software may be copyrighted by their author and need not follow the
 * licensing terms described here, provided that the new terms are
 * clearly indicated on the first page of each file where they apply.
 *
 * IN NO EVENT SHALL THE AUTHOR OR DISTRIBUTORS BE LIABLE TO ANY PARTY
 * FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
 * ARISING OUT OF THE USE OF THIS SOFTWARE, ITS DOCUMENTATION, OR ANY
 * DERIVATIVES THEREOF, EVEN IF THE AUTHOR HAVE BEEN ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * THE AUTHOR AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND
 * NON-INFRINGEMENT.  THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS,
 * AND THE AUTHOR AND DISTRIBUTORS HAVE NO OBLIGATION TO PROVIDE
 * MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 *
 * IDENTIFICATION
 *	$Header: /cvsroot/pgsql/src/pl/plpython/plpython.c,v 1.10 2001/10/25 05:50:20 momjian Exp $
 *
 *********************************************************************
 */

#include "postgres.h"

/* system stuff
 */
#include <dlfcn.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <setjmp.h>

/* postgreSQL stuff
 */
#include "executor/spi.h"
#include "commands/trigger.h"
#include "utils/elog.h"
#include "fmgr.h"
#include "access/heapam.h"

#include "tcop/tcopprot.h"
#include "utils/syscache.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"

#include <Python.h>
#include "plpython.h"

/* convert Postgresql Datum or tuple into a PyObject.
 * input to Python.  Tuples are converted to dictionary
 * objects.
 */

typedef PyObject *(*PLyDatumToObFunc) (const char *);

typedef struct PLyDatumToOb
{
	PLyDatumToObFunc func;
	FmgrInfo	typfunc;
	Oid			typelem;
	bool		typbyval;
}			PLyDatumToOb;

typedef struct PLyTupleToOb
{
	PLyDatumToOb *atts;
	int			natts;
}			PLyTupleToOb;

typedef union PLyTypeInput
{
	PLyDatumToOb d;
	PLyTupleToOb r;
}			PLyTypeInput;

/* convert PyObject to a Postgresql Datum or tuple.
 * output from Python
 */
typedef struct PLyObToDatum
{
	FmgrInfo	typfunc;
	Oid			typelem;
	bool		typbyval;
}			PLyObToDatum;

typedef struct PLyObToTuple
{
	PLyObToDatum *atts;
	int			natts;
}			PLyObToTuple;

typedef union PLyTypeOutput
{
	PLyObToDatum d;
	PLyObToTuple r;
}			PLyTypeOutput;

/* all we need to move Postgresql data to Python objects,
 * and vis versa
 */
typedef struct PLyTypeInfo
{
	PLyTypeInput in;
	PLyTypeOutput out;
	int			is_rel;
}			PLyTypeInfo;


/* cached procedure data
 */
typedef struct PLyProcedure
{
	char	   *proname;
	TransactionId fn_xmin;
	CommandId	fn_cmin;
	PLyTypeInfo result;			/* also used to store info for trigger
								 * tuple type */
	PLyTypeInfo args[FUNC_MAX_ARGS];
	int			nargs;
	PyObject   *interp;			/* restricted interpreter instance */
	PyObject   *reval;			/* interpreter return */
	PyObject   *code;			/* compiled procedure code */
	PyObject   *statics;		/* data saved across calls, local scope */
	PyObject   *globals;		/* data saved across calls, global score */
	PyObject   *me;				/* PyCObject containing pointer to this
								 * PLyProcedure */
}			PLyProcedure;


/* Python objects.
 */
typedef struct PLyPlanObject
{
	PyObject_HEAD;
	void	   *plan;			/* return of an SPI_saveplan */
	int			nargs;
	Oid		   *types;
	Datum	   *values;
	PLyTypeInfo *args;
}			PLyPlanObject;

typedef struct PLyResultObject
{
	PyObject_HEAD;
	/* HeapTuple *tuples; */
	PyObject   *nrows;			/* number of rows returned by query */
	PyObject   *rows;			/* data rows, or None if no data returned */
	PyObject   *status;			/* query status, SPI_OK_*, or SPI_ERR_* */
}			PLyResultObject;


/* function declarations
 */

/* the only exported function, with the magic telling Postgresql
 * what function call interface it implements.
 */
Datum		plpython_call_handler(PG_FUNCTION_ARGS);

PG_FUNCTION_INFO_V1(plpython_call_handler);

/* most of the remaining of the declarations, all static
 */

/* these should only be called once at the first call
 * of plpython_call_handler.  initialize the python interpreter
 * and global data.
 */
static void PLy_init_all(void);
static void PLy_init_interp(void);
static void PLy_init_safe_interp(void);
static void PLy_init_plpy(void);

/* error handler.  collects the current Python exception, if any,
 * and appends it to the error and sends it to elog
 */
static void PLy_elog(int, const char *,...);

/* call PyErr_SetString with a vprint interface
 */
static void
PLy_exception_set(PyObject *, const char *,...)
__attribute__((format(printf, 2, 3)));

/* some utility functions
 */
static void *PLy_malloc(size_t);
static void *PLy_realloc(void *, size_t);
static void PLy_free(void *);

/* sub handlers for functions and triggers
 */
static Datum PLy_function_handler(FunctionCallInfo fcinfo, PLyProcedure *);
static HeapTuple PLy_trigger_handler(FunctionCallInfo fcinfo, PLyProcedure *);

static PyObject *PLy_function_build_args(FunctionCallInfo fcinfo, PLyProcedure *);
static PyObject *PLy_trigger_build_args(FunctionCallInfo fcinfo, PLyProcedure *,
					   HeapTuple *);
static HeapTuple PLy_modify_tuple(PLyProcedure *, PyObject *,
				 TriggerData *, HeapTuple);

static PyObject *PLy_procedure_call(PLyProcedure *, char *, PyObject *);

/* returns a cached PLyProcedure, or creates, stores and returns
 * a new PLyProcedure.
 */
static PLyProcedure *PLy_procedure_get(FunctionCallInfo fcinfo, bool);

static PLyProcedure *PLy_procedure_create(FunctionCallInfo fcinfo,
					 bool is_trigger,
					 HeapTuple procTup, char *key);

static void PLy_procedure_compile(PLyProcedure *, const char *);
static char *PLy_procedure_munge_source(const char *, const char *);
static void PLy_procedure_delete(PLyProcedure *);

static void PLy_typeinfo_init(PLyTypeInfo *);
static void PLy_typeinfo_dealloc(PLyTypeInfo *);
static void PLy_output_datum_func(PLyTypeInfo *, Form_pg_type);
static void PLy_output_datum_func2(PLyObToDatum *, Form_pg_type);
static void PLy_input_datum_func(PLyTypeInfo *, Form_pg_type);
static void PLy_input_datum_func2(PLyDatumToOb *, Form_pg_type);
static void PLy_output_tuple_funcs(PLyTypeInfo *, TupleDesc);
static void PLy_input_tuple_funcs(PLyTypeInfo *, TupleDesc);

/* conversion functions
 */
static PyObject *PLyDict_FromTuple(PLyTypeInfo *, HeapTuple, TupleDesc);
static PyObject *PLyBool_FromString(const char *);
static PyObject *PLyFloat_FromString(const char *);
static PyObject *PLyInt_FromString(const char *);
static PyObject *PLyLong_FromString(const char *);
static PyObject *PLyString_FromString(const char *);


/* global data
 */
static int	PLy_first_call = 1;
static volatile int PLy_call_level = 0;

/* this gets modified in plpython_call_handler and PLy_elog.
 * test it any old where, but do NOT modify it anywhere except
 * those two functions
 */
static volatile int PLy_restart_in_progress = 0;

static PyObject *PLy_interp_globals = NULL;
static PyObject *PLy_interp_safe = NULL;
static PyObject *PLy_interp_safe_globals = NULL;
static PyObject *PLy_importable_modules = NULL;
static PyObject *PLy_procedure_cache = NULL;

char	   *PLy_importable_modules_list[] = {
	"array",
	"bisect",
	"calendar",
	"cmath",
	"errno",
	"marshal",
	"math",
	"md5",
	"mpz",
	"operator",
	"pickle",
	"random",
	"re",
	"sha",
	"string",
	"StringIO",
	"time",
	"whrandom",
	"zlib"
};

/* Python exceptions
 */
PyObject   *PLy_exc_error = NULL;
PyObject   *PLy_exc_fatal = NULL;
PyObject   *PLy_exc_spi_error = NULL;

/* some globals for the python module
 */
static char PLy_plan_doc[] = {
	"Store a PostgreSQL plan"
};

static char PLy_result_doc[] = {
	"Results of a PostgreSQL query"
};


#if DEBUG_EXC
volatile int exc_save_calls = 0;
volatile int exc_restore_calls = 0;
volatile int func_enter_calls = 0;
volatile int func_leave_calls = 0;
#endif

/*
 * the function definitions
 */

/*
 * This routine is a crock, and so is everyplace that calls it.  The problem
 * is that the cached form of plpython functions/queries is allocated permanently
 * (mostly via malloc()) and never released until backend exit.  Subsidiary
 * data structures such as fmgr info records therefore must live forever
 * as well.  A better implementation would store all this stuff in a per-
 * function memory context that could be reclaimed at need.  In the meantime,
 * fmgr_info_cxt must be called specifying TopMemoryContext so that whatever
 * it might allocate, and whatever the eventual function might allocate using
 * fn_mcxt, will live forever too.
 */
static void
perm_fmgr_info(Oid functionId, FmgrInfo *finfo)
{
	fmgr_info_cxt(functionId, finfo, TopMemoryContext);
}


Datum
plpython_call_handler(PG_FUNCTION_ARGS)
{
	DECLARE_EXC();
	Datum		retval;
	bool		is_trigger;
	PLyProcedure *volatile proc = NULL;

	enter();

	if (PLy_first_call)
		PLy_init_all();

	if (SPI_connect() != SPI_OK_CONNECT)
		elog(ERROR, "plpython: Unable to connect to SPI manager");

	CALL_LEVEL_INC();
	is_trigger = CALLED_AS_TRIGGER(fcinfo);

	SAVE_EXC();
	if (TRAP_EXC())
	{
		RESTORE_EXC();
		CALL_LEVEL_DEC();
		if (PLy_call_level == 0)
		{
			PLy_restart_in_progress = 0;
			PyErr_Clear();
		}
		else
			PLy_restart_in_progress += 1;
		if (proc)
			Py_DECREF(proc->me);
		RERAISE_EXC();
	}

	/*
	 * elog(NOTICE, "PLy_restart_in_progress is %d",
	 * PLy_restart_in_progress);
	 */

	proc = PLy_procedure_get(fcinfo, is_trigger);

	if (is_trigger)
	{
		HeapTuple	trv = PLy_trigger_handler(fcinfo, proc);

		retval = PointerGetDatum(trv);
	}
	else
		retval = PLy_function_handler(fcinfo, proc);

	CALL_LEVEL_DEC();
	RESTORE_EXC();

	Py_DECREF(proc->me);
	refc(proc->me);

	return retval;
}

/* trigger and function sub handlers
 *
 * the python function is expected to return Py_None if the tuple is
 * acceptable and unmodified.  Otherwise it should return a PyString
 * object who's value is SKIP, or MODIFY.  SKIP means don't perform
 * this action.  MODIFY means the tuple has been modified, so update
 * tuple and perform action.  SKIP and MODIFY assume the trigger fires
 * BEFORE the event and is ROW level.  postgres expects the function
 * to take no arguments and return an argument of type opaque.
 */
HeapTuple
PLy_trigger_handler(FunctionCallInfo fcinfo, PLyProcedure * proc)
{
	DECLARE_EXC();
	HeapTuple	rv = NULL;
	PyObject   *volatile plargs = NULL;
	PyObject   *volatile plrv = NULL;

	enter();

	SAVE_EXC();
	if (TRAP_EXC())
	{
		RESTORE_EXC();

		Py_XDECREF(plargs);
		Py_XDECREF(plrv);

		RERAISE_EXC();
	}

	plargs = PLy_trigger_build_args(fcinfo, proc, &rv);
	plrv = PLy_procedure_call(proc, "TD", plargs);

	/*
	 * Disconnect from SPI manager
	 */
	if (SPI_finish() != SPI_OK_FINISH)
		elog(ERROR, "plpython: SPI_finish failed");

	if (plrv == NULL)
		elog(FATAL, "Aiieee, PLy_procedure_call returned NULL");

	if (PLy_restart_in_progress)
		elog(FATAL, "Aiieee, restart in progress not expected");

	/*
	 * return of None means we're happy with the tuple
	 */
	if (plrv != Py_None)
	{
		char	   *srv;

		if (!PyString_Check(plrv))
			elog(ERROR, "plpython: Expected trigger to return None or a String");

		srv = PyString_AsString(plrv);
		if (strcasecmp(srv, "SKIP") == 0)
			rv = NULL;
		else if (strcasecmp(srv, "MODIFY") == 0)
		{
			TriggerData *tdata = (TriggerData *) fcinfo->context;

			if ((TRIGGER_FIRED_BY_INSERT(tdata->tg_event)) ||
				(TRIGGER_FIRED_BY_UPDATE(tdata->tg_event)))
				rv = PLy_modify_tuple(proc, plargs, tdata, rv);
			else
				elog(NOTICE, "plpython: Ignoring modified tuple in DELETE trigger");
		}
		else if (strcasecmp(srv, "OK"))
		{
			/*
			 * hmmm, perhaps they only read the pltcl page, not a
			 * surprising thing since i've written no documentation, so
			 * accept a belated OK
			 */
			elog(ERROR, "plpython: Expected return to be 'SKIP' or 'MODIFY'");
		}
	}

	Py_DECREF(plargs);
	Py_DECREF(plrv);

	RESTORE_EXC();

	return rv;
}

HeapTuple
PLy_modify_tuple(PLyProcedure * proc, PyObject * pltd, TriggerData *tdata,
				 HeapTuple otup)
{
	DECLARE_EXC();
	PyObject   *volatile plntup;
	PyObject   *volatile plkeys;
	PyObject   *volatile platt;
	PyObject   *volatile plval;
	PyObject   *volatile plstr;
	HeapTuple	rtup;
	int			natts,
				i,
				j,
				attn,
				atti;
	int		   *volatile modattrs;
	Datum	   *volatile modvalues;
	char	   *volatile modnulls;
	TupleDesc	tupdesc;

	plntup = plkeys = platt = plval = plstr = NULL;
	modattrs = NULL;
	modvalues = NULL;
	modnulls = NULL;

	enter();

	SAVE_EXC();
	if (TRAP_EXC())
	{
		RESTORE_EXC();

		Py_XDECREF(plntup);
		Py_XDECREF(plkeys);
		Py_XDECREF(platt);
		Py_XDECREF(plval);
		Py_XDECREF(plstr);

		if (modnulls)
			pfree(modnulls);
		if (modvalues)
			pfree(modvalues);
		if (modattrs)
			pfree(modattrs);

		RERAISE_EXC();
	}

	if ((plntup = PyDict_GetItemString(pltd, "new")) == NULL)
		elog(ERROR, "plpython: TD[\"new\"] deleted, unable to modify tuple");
	if (!PyDict_Check(plntup))
		elog(ERROR, "plpython: TD[\"new\"] is not a dictionary object");
	Py_INCREF(plntup);

	plkeys = PyDict_Keys(plntup);
	natts = PyList_Size(plkeys);

	if (natts != proc->result.out.r.natts)
		elog(ERROR, "plpython: TD[\"new\"] has an incorrect number of keys.");

	modattrs = palloc(natts * sizeof(int));
	modvalues = palloc(natts * sizeof(Datum));
	for (i = 0; i < natts; i++)
	{
		modattrs[i] = i + 1;
		modvalues[i] = (Datum) NULL;
	}
	modnulls = palloc(natts + 1);
	memset(modnulls, 'n', natts);
	modnulls[natts] = '\0';

	tupdesc = tdata->tg_relation->rd_att;

	for (j = 0; j < natts; j++)
	{
		char	   *src;

		platt = PyList_GetItem(plkeys, j);
		if (!PyString_Check(platt))
			elog(ERROR, "plpython: attribute is not a string");
		attn = modattrs[j] = SPI_fnumber(tupdesc, PyString_AsString(platt));

		if (attn == SPI_ERROR_NOATTRIBUTE)
			elog(ERROR, "plpython: invalid attribute `%s' in tuple.",
				 PyString_AsString(platt));
		atti = attn - 1;

		plval = PyDict_GetItem(plntup, platt);
		if (plval == NULL)
			elog(FATAL, "plpython: interpreter is probably corrupted");

		Py_INCREF(plval);

		if (plval != Py_None)
		{
			plstr = PyObject_Str(plval);
			src = PyString_AsString(plstr);

			modvalues[j] = FunctionCall3(&proc->result.out.r.atts[atti].typfunc,
										 CStringGetDatum(src),
				 ObjectIdGetDatum(proc->result.out.r.atts[atti].typelem),
							Int32GetDatum(tupdesc->attrs[j]->atttypmod));
			modnulls[j] = ' ';

			Py_DECREF(plstr);
			plstr = NULL;
		}
		Py_DECREF(plval);
		plval = NULL;

	}
	rtup = SPI_modifytuple(tdata->tg_relation, otup, natts, modattrs,
						   modvalues, modnulls);

	/*
	 * FIXME -- these leak if not explicity pfree'd by other elog calls,
	 * no?
	 */
	pfree(modattrs);
	pfree(modvalues);
	pfree(modnulls);

	if (rtup == NULL)
		elog(ERROR, "plpython: SPI_modifytuple failed -- error %d", SPI_result);

	Py_DECREF(plntup);
	Py_DECREF(plkeys);

	RESTORE_EXC();

	return rtup;
}

PyObject *
PLy_trigger_build_args(FunctionCallInfo fcinfo, PLyProcedure * proc, HeapTuple *rv)
{
	DECLARE_EXC();
	TriggerData *tdata;
	PyObject   *pltname,
			   *pltevent,
			   *pltwhen,
			   *pltlevel,
			   *pltrelid;
	PyObject   *pltargs,
			   *pytnew,
			   *pytold;
	PyObject   *volatile pltdata = NULL;
	char	   *stroid;

	enter();

	SAVE_EXC();
	if (TRAP_EXC())
	{
		RESTORE_EXC();

		Py_XDECREF(pltdata);

		RERAISE_EXC();
	}

	tdata = (TriggerData *) fcinfo->context;

	pltdata = PyDict_New();
	if (!pltdata)
		PLy_elog(ERROR, "Unable to build arguments for trigger procedure");

	pltname = PyString_FromString(tdata->tg_trigger->tgname);
	PyDict_SetItemString(pltdata, "name", pltname);
	Py_DECREF(pltname);

	stroid = DatumGetCString(DirectFunctionCall1(oidout,
						   ObjectIdGetDatum(tdata->tg_relation->rd_id)));
	pltrelid = PyString_FromString(stroid);
	PyDict_SetItemString(pltdata, "relid", pltrelid);
	Py_DECREF(pltrelid);
	pfree(stroid);



	if (TRIGGER_FIRED_BEFORE(tdata->tg_event))
		pltwhen = PyString_FromString("BEFORE");
	else if (TRIGGER_FIRED_AFTER(tdata->tg_event))
		pltwhen = PyString_FromString("AFTER");
	else
		pltwhen = PyString_FromString("UNKNOWN");
	PyDict_SetItemString(pltdata, "when", pltwhen);
	Py_DECREF(pltwhen);

	if (TRIGGER_FIRED_FOR_ROW(tdata->tg_event))
		pltlevel = PyString_FromString("ROW");
	else if (TRIGGER_FIRED_FOR_STATEMENT(tdata->tg_event))
		pltlevel = PyString_FromString("STATEMENT");
	else
		pltlevel = PyString_FromString("UNKNOWN");
	PyDict_SetItemString(pltdata, "level", pltlevel);
	Py_DECREF(pltlevel);

	if (TRIGGER_FIRED_BY_INSERT(tdata->tg_event))
	{
		pltevent = PyString_FromString("INSERT");
		PyDict_SetItemString(pltdata, "old", Py_None);
		pytnew = PLyDict_FromTuple(&(proc->result), tdata->tg_trigtuple,
								   tdata->tg_relation->rd_att);
		PyDict_SetItemString(pltdata, "new", pytnew);
		Py_DECREF(pytnew);
		*rv = tdata->tg_trigtuple;
	}
	else if (TRIGGER_FIRED_BY_DELETE(tdata->tg_event))
	{
		pltevent = PyString_FromString("DELETE");
		PyDict_SetItemString(pltdata, "new", Py_None);
		pytold = PLyDict_FromTuple(&(proc->result), tdata->tg_trigtuple,
								   tdata->tg_relation->rd_att);
		PyDict_SetItemString(pltdata, "old", pytold);
		Py_DECREF(pytold);
		*rv = tdata->tg_trigtuple;
	}
	else if (TRIGGER_FIRED_BY_UPDATE(tdata->tg_event))
	{
		pltevent = PyString_FromString("UPDATE");
		pytnew = PLyDict_FromTuple(&(proc->result), tdata->tg_newtuple,
								   tdata->tg_relation->rd_att);
		PyDict_SetItemString(pltdata, "new", pytnew);
		Py_DECREF(pytnew);
		pytold = PLyDict_FromTuple(&(proc->result), tdata->tg_trigtuple,
								   tdata->tg_relation->rd_att);
		PyDict_SetItemString(pltdata, "old", pytold);
		Py_DECREF(pytold);
		*rv = tdata->tg_newtuple;
	}
	else
	{
		pltevent = PyString_FromString("UNKNOWN");
		PyDict_SetItemString(pltdata, "old", Py_None);
		PyDict_SetItemString(pltdata, "new", Py_None);
		*rv = tdata->tg_trigtuple;
	}
	PyDict_SetItemString(pltdata, "event", pltevent);
	Py_DECREF(pltevent);

	if (tdata->tg_trigger->tgnargs)
	{
		/*
		 * all strings...
		 */
		int			i;
		PyObject   *pltarg;

		pltargs = PyList_New(tdata->tg_trigger->tgnargs);
		for (i = 0; i < tdata->tg_trigger->tgnargs; i++)
		{
			pltarg = PyString_FromString(tdata->tg_trigger->tgargs[i]);

			/*
			 * stolen, don't Py_DECREF
			 */
			PyList_SetItem(pltargs, i, pltarg);
		}
	}
	else
	{
		Py_INCREF(Py_None);
		pltargs = Py_None;
	}
	PyDict_SetItemString(pltdata, "args", pltargs);
	Py_DECREF(pltargs);

	RESTORE_EXC();

	return pltdata;
}



/* function handler and friends
 */
Datum
PLy_function_handler(FunctionCallInfo fcinfo, PLyProcedure * proc)
{
	DECLARE_EXC();
	Datum		rv;
	PyObject   *volatile plargs = NULL;
	PyObject   *volatile plrv = NULL;
	PyObject   *volatile plrv_so = NULL;
	char	   *plrv_sc;

	enter();

	/*
	 * setup to catch elog in while building function arguments, and
	 * DECREF the plargs if the function call fails
	 */
	SAVE_EXC();
	if (TRAP_EXC())
	{
		RESTORE_EXC();

		Py_XDECREF(plargs);
		Py_XDECREF(plrv);
		Py_XDECREF(plrv_so);

		RERAISE_EXC();
	}

	plargs = PLy_function_build_args(fcinfo, proc);
	plrv = PLy_procedure_call(proc, "args", plargs);

	/*
	 * Disconnect from SPI manager and then create the return values datum
	 * (if the input function does a palloc for it this must not be
	 * allocated in the SPI memory context because SPI_finish would free
	 * it).
	 */
	if (SPI_finish() != SPI_OK_FINISH)
		elog(ERROR, "plpython: SPI_finish failed");

	if (plrv == NULL)
	{
		elog(FATAL, "Aiieee, PLy_procedure_call returned NULL");
#if 0
		if (!PLy_restart_in_progress)
			PLy_elog(ERROR, "plpython: Function \"%s\" failed.", proc->proname);

		/*
		 * FIXME is this dead code?  i'm pretty sure it is for unnested
		 * calls, but not for nested calls
		 */
		RAISE_EXC(1);
#endif
	}

	/*
	 * convert the python PyObject to a postgresql Datum FIXME returning a
	 * NULL, ie PG_RETURN_NULL() blows the backend to small messy bits...
	 * it this a bug or expected?  so just call with the string value of
	 * None for now
	 */

	if (plrv == Py_None)
	{
		fcinfo->isnull = true;
		rv = (Datum) NULL;
	}
	else
	{
		fcinfo->isnull = false;
		plrv_so = PyObject_Str(plrv);
		plrv_sc = PyString_AsString(plrv_so);
		rv = FunctionCall3(&proc->result.out.d.typfunc,
						   PointerGetDatum(plrv_sc),
						   ObjectIdGetDatum(proc->result.out.d.typelem),
						   Int32GetDatum(-1));
	}

	RESTORE_EXC();

	Py_XDECREF(plargs);
	Py_DECREF(plrv);
	Py_XDECREF(plrv_so);

	return rv;
}

PyObject *
PLy_procedure_call(PLyProcedure * proc, char *kargs, PyObject * vargs)
{
	PyObject   *rv;

	enter();

	PyDict_SetItemString(proc->globals, kargs, vargs);
	rv = PyObject_CallFunction(proc->reval, "O", proc->code);

	if ((rv == NULL) || (PyErr_Occurred()))
	{
		Py_XDECREF(rv);
		if (!PLy_restart_in_progress)
			PLy_elog(ERROR, "Call of function `%s' failed.", proc->proname);
		RAISE_EXC(1);
	}

	return rv;
}

PyObject *
PLy_function_build_args(FunctionCallInfo fcinfo, PLyProcedure * proc)
{
	DECLARE_EXC();
	PyObject   *volatile arg = NULL;
	PyObject   *volatile args = NULL;
	int			i;

	enter();

	/*
	 * FIXME -- if the setjmp setup is expensive, add the arg and args
	 * field to the procedure struct and cleanup at the start of the next
	 * call
	 */
	SAVE_EXC();
	if (TRAP_EXC())
	{
		RESTORE_EXC();
		Py_XDECREF(arg);
		Py_XDECREF(args);

		RERAISE_EXC();
	}

	args = PyList_New(proc->nargs);
	for (i = 0; i < proc->nargs; i++)
	{
		if (proc->args[i].is_rel == 1)
		{
			TupleTableSlot *slot = (TupleTableSlot *) fcinfo->arg[i];

			arg = PLyDict_FromTuple(&(proc->args[i]), slot->val,
									slot->ttc_tupleDescriptor);
		}
		else
		{
			if (!fcinfo->argnull[i])
			{
				char	   *ct;
				Datum		dt;

				dt = FunctionCall3(&(proc->args[i].in.d.typfunc),
								   fcinfo->arg[i],
							ObjectIdGetDatum(proc->args[i].in.d.typelem),
								   Int32GetDatum(-1));
				ct = DatumGetCString(dt);
				arg = (proc->args[i].in.d.func) (ct);
				pfree(ct);
			}
			else
				arg = NULL;
		}

		if (arg == NULL)
		{
			Py_INCREF(Py_None);
			arg = Py_None;
		}

		/*
		 * FIXME -- error check this
		 */
		PyList_SetItem(args, i, arg);
	}

	RESTORE_EXC();

	return args;
}


/* PLyProcedure functions
 */
static PLyProcedure *
PLy_procedure_get(FunctionCallInfo fcinfo, bool is_trigger)
{
	Oid			fn_oid;
	HeapTuple	procTup;
	char		key[128];
	PyObject   *plproc;
	PLyProcedure *proc = NULL;
	int			rv;

	enter();

	fn_oid = fcinfo->flinfo->fn_oid;
	procTup = SearchSysCache(PROCOID,
							 ObjectIdGetDatum(fn_oid),
							 0, 0, 0);
	if (!HeapTupleIsValid(procTup))
		elog(ERROR, "plpython: cache lookup for procedure %u failed", fn_oid);

	rv = snprintf(key, sizeof(key), "%u%s",
				  fn_oid,
				  is_trigger ? "_trigger" : "");
	if ((rv >= sizeof(key)) || (rv < 0))
		elog(FATAL, "plpython: Buffer overrun in %s:%d", __FILE__, __LINE__);

	plproc = PyDict_GetItemString(PLy_procedure_cache, key);

	if (plproc != NULL)
	{
		Py_INCREF(plproc);
		if (!PyCObject_Check(plproc))
			elog(FATAL, "plpython: Expected a PyCObject, didn't get one");

		mark();

		proc = PyCObject_AsVoidPtr(plproc);
		if (proc->me != plproc)
			elog(FATAL, "plpython: Aiieee, proc->me != plproc");
		/* did we find an up-to-date cache entry? */
		if (proc->fn_xmin != procTup->t_data->t_xmin ||
			proc->fn_cmin != procTup->t_data->t_cmin)
		{
			Py_DECREF(plproc);
			proc = NULL;
		}
	}

	if (proc == NULL)
		proc = PLy_procedure_create(fcinfo, is_trigger, procTup, key);

	ReleaseSysCache(procTup);

	return proc;
}

static PLyProcedure *
PLy_procedure_create(FunctionCallInfo fcinfo, bool is_trigger,
					 HeapTuple procTup, char *key)
{
	char		procName[256];

	DECLARE_EXC();
	Form_pg_proc procStruct;
	PLyProcedure *volatile proc;
	char	   *volatile procSource = NULL;
	Datum		procDatum;
	int			i,
				rv;

	enter();

	procStruct = (Form_pg_proc) GETSTRUCT(procTup);

	rv = snprintf(procName, sizeof(procName),
				  "__plpython_procedure_%s_%u%s",
				  NameStr(procStruct->proname),
				  fcinfo->flinfo->fn_oid,
				  is_trigger ? "_trigger" : "");
	if ((rv >= sizeof(procName)) || (rv < 0))
		elog(FATAL, "plpython: Procedure name would overrun buffer");

	proc = PLy_malloc(sizeof(PLyProcedure));
	proc->proname = PLy_malloc(strlen(procName) + 1);
	strcpy(proc->proname, procName);
	proc->fn_xmin = procTup->t_data->t_xmin;
	proc->fn_cmin = procTup->t_data->t_cmin;
	PLy_typeinfo_init(&proc->result);
	for (i = 0; i < FUNC_MAX_ARGS; i++)
		PLy_typeinfo_init(&proc->args[i]);
	proc->nargs = 0;
	proc->code = proc->interp = proc->reval = proc->statics = NULL;
	proc->globals = proc->me = NULL;

	SAVE_EXC();
	if (TRAP_EXC())
	{
		RESTORE_EXC();
		PLy_procedure_delete(proc);
		if (procSource)
			pfree(procSource);
		RERAISE_EXC();
	}

	/*
	 * get information required for output conversion of the return value,
	 * but only if this isn't a trigger.
	 */
	if (!is_trigger)
	{
		HeapTuple	rvTypeTup;
		Form_pg_type rvTypeStruct;
		Datum		rvDatum;

		rvDatum = ObjectIdGetDatum(procStruct->prorettype);
		rvTypeTup = SearchSysCache(TYPEOID, rvDatum, 0, 0, 0);
		if (!HeapTupleIsValid(rvTypeTup))
			elog(ERROR, "plpython: cache lookup for type \"%u\" failed",
				 procStruct->prorettype);

		rvTypeStruct = (Form_pg_type) GETSTRUCT(rvTypeTup);
		if (rvTypeStruct->typrelid == InvalidOid)
			PLy_output_datum_func(&proc->result, rvTypeStruct);
		else
			elog(ERROR, "plpython: tuple return types not supported, yet");

		ReleaseSysCache(rvTypeTup);
	}
	else
	{
		/*
		 * input/output conversion for trigger tuples.	use the result
		 * TypeInfo variable to store the tuple conversion info.
		 */
		TriggerData *tdata = (TriggerData *) fcinfo->context;

		PLy_input_tuple_funcs(&(proc->result), tdata->tg_relation->rd_att);
		PLy_output_tuple_funcs(&(proc->result), tdata->tg_relation->rd_att);
	}

	/*
	 * now get information required for input conversion of the procedures
	 * arguments.
	 */
	proc->nargs = fcinfo->nargs;
	for (i = 0; i < fcinfo->nargs; i++)
	{
		HeapTuple	argTypeTup;
		Form_pg_type argTypeStruct;
		Datum		argDatum;

		argDatum = ObjectIdGetDatum(procStruct->proargtypes[i]);
		argTypeTup = SearchSysCache(TYPEOID, argDatum, 0, 0, 0);
		if (!HeapTupleIsValid(argTypeTup))
			elog(ERROR, "plpython: cache lookup for type \"%u\" failed",
				 procStruct->proargtypes[i]);
		argTypeStruct = (Form_pg_type) GETSTRUCT(argTypeTup);

		if (argTypeStruct->typrelid == InvalidOid)
			PLy_input_datum_func(&(proc->args[i]), argTypeStruct);
		else
		{
			TupleTableSlot *slot = (TupleTableSlot *) fcinfo->arg[i];

			PLy_input_tuple_funcs(&(proc->args[i]),
								  slot->ttc_tupleDescriptor);
		}

		ReleaseSysCache(argTypeTup);
	}


	/*
	 * get the text of the function.
	 */
	procDatum = DirectFunctionCall1(textout,
									PointerGetDatum(&procStruct->prosrc));
	procSource = DatumGetCString(procDatum);

	PLy_procedure_compile(proc, procSource);

	pfree(procSource);

	proc->me = PyCObject_FromVoidPtr(proc, NULL);
	PyDict_SetItemString(PLy_procedure_cache, key, proc->me);

	RESTORE_EXC();

	return proc;
}

void
PLy_procedure_compile(PLyProcedure * proc, const char *src)
{
	PyObject   *module,
			   *crv = NULL;
	char	   *msrc;

	enter();

	/*
	 * get an instance of rexec.RExec for the function
	 */
	proc->interp = PyObject_CallMethod(PLy_interp_safe, "RExec", NULL);
	if ((proc->interp == NULL) || (PyErr_Occurred()))
		PLy_elog(ERROR, "Unable to create rexec.RExec instance");

	/*
	 * tweak the list of permitted modules
	 */
	PyObject_SetAttrString(proc->interp, "ok_builtin_modules",
						   PLy_importable_modules);

	proc->reval = PyObject_GetAttrString(proc->interp, "r_eval");
	if ((proc->reval == NULL) || (PyErr_Occurred()))
		PLy_elog(ERROR, "Unable to get method `r_eval' from rexec.RExec");

	/*
	 * add a __main__ module to the function's interpreter
	 */
	module = PyObject_CallMethod(proc->interp, "add_module", "s", "__main__");
	if ((module == NULL) || (PyErr_Occurred()))
		PLy_elog(ERROR, "Unable to get module `__main__' from rexec.RExec");

	/*
	 * add plpy module to the interpreters main dictionary
	 */
	proc->globals = PyModule_GetDict(module);
	if ((proc->globals == NULL) || (PyErr_Occurred()))
		PLy_elog(ERROR, "Unable to get `__main__.__dict__' from rexec.RExec");

	/*
	 * why the hell won't r_import or r_exec('import plpy') work?
	 */
	module = PyDict_GetItemString(PLy_interp_globals, "plpy");
	if ((module == NULL) || (PyErr_Occurred()))
		PLy_elog(ERROR, "Unable to get `plpy'");
	Py_INCREF(module);
	PyDict_SetItemString(proc->globals, "plpy", module);

	/*
	 * SD is private preserved data between calls GD is global data shared
	 * by all functions
	 */
	proc->statics = PyDict_New();
	PyDict_SetItemString(proc->globals, "SD", proc->statics);
	PyDict_SetItemString(proc->globals, "GD", PLy_interp_safe_globals);

	/*
	 * insert the function code into the interpreter
	 */
	msrc = PLy_procedure_munge_source(proc->proname, src);
	crv = PyObject_CallMethod(proc->interp, "r_exec", "s", msrc);
	free(msrc);

	if ((crv != NULL) && (!PyErr_Occurred()))
	{
		int			clen;
		char		call[256];

		Py_DECREF(crv);

		/*
		 * compile a call to the function
		 */
		clen = snprintf(call, sizeof(call), "%s()", proc->proname);
		if ((clen < 0) || (clen >= sizeof(call)))
			elog(ERROR, "plpython: string would overflow buffer.");
		proc->code = Py_CompileString(call, "<string>", Py_eval_input);
		if ((proc->code != NULL) && (!PyErr_Occurred()))
			return;
	}
	else
		Py_XDECREF(crv);

	PLy_elog(ERROR, "Unable to compile function %s", proc->proname);
}

char *
PLy_procedure_munge_source(const char *name, const char *src)
{
	char	   *mrc,
			   *mp;
	const char *sp;
	size_t		mlen,
				plen;

	enter();

	/*
	 * room for function source and the def statement
	 */
	mlen = (strlen(src) * 2) + strlen(name) + 16;

	mrc = PLy_malloc(mlen);
	plen = snprintf(mrc, mlen, "def %s():\n\t", name);
	if ((plen < 0) || (plen >= mlen))
		elog(FATAL, "Aiieee, impossible buffer overrun (or snprintf failure)");

	sp = src;
	mp = mrc + plen;

	while (*sp != '\0')
	{
		if (*sp == '\n')
		{
			*mp++ = *sp++;
			*mp++ = '\t';
		}
		else
			*mp++ = *sp++;
	}
	*mp++ = '\n';
	*mp++ = '\n';
	*mp = '\0';

	if (mp > (mrc + mlen))
		elog(FATAL, "plpython: Buffer overrun in PLy_munge_source");

	return mrc;
}

void
PLy_procedure_delete(PLyProcedure * proc)
{
	int			i;

	enter();

	Py_XDECREF(proc->code);
	Py_XDECREF(proc->interp);
	Py_XDECREF(proc->reval);
	Py_XDECREF(proc->statics);
	Py_XDECREF(proc->globals);
	Py_XDECREF(proc->me);
	if (proc->proname)
		PLy_free(proc->proname);
	for (i = 0; i < proc->nargs; i++)
		if (proc->args[i].is_rel == 1)
		{
			if (proc->args[i].in.r.atts)
				PLy_free(proc->args[i].in.r.atts);
			if (proc->args[i].out.r.atts)
				PLy_free(proc->args[i].out.r.atts);
		}

	leave();
}

/* conversion functions.  remember output from python is
 * input to postgresql, and vis versa.
 */
void
PLy_input_tuple_funcs(PLyTypeInfo * arg, TupleDesc desc)
{
	int			i;
	Datum		datum;

	enter();

	if (arg->is_rel == 0)
		elog(FATAL, "plpython: PLyTypeInfo struct is initialized for a Datum");

	arg->is_rel = 1;
	arg->in.r.natts = desc->natts;
	arg->in.r.atts = malloc(desc->natts * sizeof(PLyDatumToOb));

	for (i = 0; i < desc->natts; i++)
	{
		HeapTuple	typeTup;
		Form_pg_type typeStruct;

		datum = ObjectIdGetDatum(desc->attrs[i]->atttypid);
		typeTup = SearchSysCache(TYPEOID, datum, 0, 0, 0);
		if (!HeapTupleIsValid(typeTup))
		{
			char	   *attname = NameStr(desc->attrs[i]->attname);

			elog(ERROR, "plpython: Cache lookup for attribute `%s' type `%u' failed",
				 attname, desc->attrs[i]->atttypid);
		}

		typeStruct = (Form_pg_type) GETSTRUCT(typeTup);

		PLy_input_datum_func2(&(arg->in.r.atts[i]), typeStruct);

		ReleaseSysCache(typeTup);
	}
}

void
PLy_output_tuple_funcs(PLyTypeInfo * arg, TupleDesc desc)
{
	int			i;
	Datum		datum;

	enter();

	if (arg->is_rel == 0)
		elog(FATAL, "plpython: PLyTypeInfo struct is initialized for a Datum");

	arg->is_rel = 1;
	arg->out.r.natts = desc->natts;
	arg->out.r.atts = malloc(desc->natts * sizeof(PLyDatumToOb));

	for (i = 0; i < desc->natts; i++)
	{
		HeapTuple	typeTup;
		Form_pg_type typeStruct;

		datum = ObjectIdGetDatum(desc->attrs[i]->atttypid);
		typeTup = SearchSysCache(TYPEOID, datum, 0, 0, 0);
		if (!HeapTupleIsValid(typeTup))
		{
			char	   *attname = NameStr(desc->attrs[i]->attname);

			elog(ERROR, "plpython: Cache lookup for attribute `%s' type `%u' failed",
				 attname, desc->attrs[i]->atttypid);
		}

		typeStruct = (Form_pg_type) GETSTRUCT(typeTup);

		PLy_output_datum_func2(&(arg->out.r.atts[i]), typeStruct);

		ReleaseSysCache(typeTup);
	}
}

void
PLy_output_datum_func(PLyTypeInfo * arg, Form_pg_type typeStruct)
{
	enter();

	if (arg->is_rel == 1)
		elog(FATAL, "plpython: PLyTypeInfo struct is initialized for a Tuple");
	arg->is_rel = 0;
	PLy_output_datum_func2(&(arg->out.d), typeStruct);
}

void
PLy_output_datum_func2(PLyObToDatum * arg, Form_pg_type typeStruct)
{
	enter();

	perm_fmgr_info(typeStruct->typinput, &arg->typfunc);
	arg->typelem = typeStruct->typelem;
	arg->typbyval = typeStruct->typbyval;
}

void
PLy_input_datum_func(PLyTypeInfo * arg, Form_pg_type typeStruct)
{
	enter();

	if (arg->is_rel == 1)
		elog(FATAL, "plpython: PLyTypeInfo struct is initialized for Tuple");
	arg->is_rel = 0;
	PLy_input_datum_func2(&(arg->in.d), typeStruct);
}

void
PLy_input_datum_func2(PLyDatumToOb * arg, Form_pg_type typeStruct)
{
	char	   *type;

	perm_fmgr_info(typeStruct->typoutput, &arg->typfunc);
	arg->typelem = typeStruct->typelem;
	arg->typbyval = typeStruct->typbyval;

	/*
	 * hmmm, wierd.  means this arg will always be converted to a python
	 * None
	 */
	if (!OidIsValid(typeStruct->typoutput))
	{
		elog(ERROR, "plpython: (FIXME) typeStruct->typoutput is invalid");

		arg->func = NULL;
		return;
	}

	type = NameStr(typeStruct->typname);
	switch (type[0])
	{
		case 'b':
			{
				if (strcasecmp("bool", type))
				{
					arg->func = PLyBool_FromString;
					return;
				}
				break;
			}
		case 'f':
			{
				if ((strncasecmp("float", type, 5) == 0) &&
					((type[5] == '8') || (type[5] == '4')))
				{
					arg->func = PLyFloat_FromString;
					return;
				}
				break;
			}
		case 'i':
			{
				if ((strncasecmp("int", type, 3) == 0) &&
					((type[3] == '4') || (type[3] == '2')) &&
					(type[4] == '\0'))
				{
					arg->func = PLyInt_FromString;
					return;
				}
				else if (strcasecmp("int8", type) == 0)
					arg->func = PLyLong_FromString;
				break;
			}
		case 'n':
			{
				if (strcasecmp("numeric", type) == 0)
				{
					arg->func = PLyFloat_FromString;
					return;
				}
				break;
			}
		default:
			break;
	}
	arg->func = PLyString_FromString;
}

void
PLy_typeinfo_init(PLyTypeInfo * arg)
{
	arg->is_rel = -1;
	arg->in.r.natts = arg->out.r.natts = 0;
	arg->in.r.atts = NULL;
	arg->out.r.atts = NULL;
}

void
PLy_typeinfo_dealloc(PLyTypeInfo * arg)
{
	if (arg->is_rel == 1)
	{
		if (arg->in.r.atts)
			PLy_free(arg->in.r.atts);
		if (arg->out.r.atts)
			PLy_free(arg->out.r.atts);
	}
}

/* assumes that a bool is always returned as a 't' or 'f'
 */
PyObject *
PLyBool_FromString(const char *src)
{
	enter();

	if (src[0] == 't')
		return PyInt_FromLong(1);
	return PyInt_FromLong(0);
}

PyObject *
PLyFloat_FromString(const char *src)
{
	double		v;
	char	   *eptr;

	enter();

	errno = 0;
	v = strtod(src, &eptr);
	if ((*eptr != '\0') || (errno))
		return NULL;
	return PyFloat_FromDouble(v);
}

PyObject *
PLyInt_FromString(const char *src)
{
	long		v;
	char	   *eptr;

	enter();

	errno = 0;
	v = strtol(src, &eptr, 0);
	if ((*eptr != '\0') || (errno))
		return NULL;
	return PyInt_FromLong(v);
}

PyObject *
PLyLong_FromString(const char *src)
{
	return PyLong_FromString((char *) src, NULL, 0);
}

PyObject *
PLyString_FromString(const char *src)
{
	return PyString_FromString(src);
}

PyObject *
PLyDict_FromTuple(PLyTypeInfo * info, HeapTuple tuple, TupleDesc desc)
{
	DECLARE_EXC();
	PyObject   *volatile dict;
	int			i;

	enter();

	if (info->is_rel != 1)
		elog(FATAL, "plpython: PLyTypeInfo structure describes a datum.");

	dict = PyDict_New();
	if (dict == NULL)
		PLy_elog(ERROR, "Unable to create tuple dictionary.");

	SAVE_EXC();
	if (TRAP_EXC())
	{
		RESTORE_EXC();
		Py_DECREF(dict);

		RERAISE_EXC();
	}

	for (i = 0; i < info->in.r.natts; i++)
	{
		char	   *key,
				   *vsrc;
		Datum		vattr,
					vdat;
		bool		is_null;
		PyObject   *value;

		key = NameStr(desc->attrs[i]->attname);
		vattr = heap_getattr(tuple, (i + 1), desc, &is_null);

		if ((is_null) || (info->in.r.atts[i].func == NULL))
			PyDict_SetItemString(dict, key, Py_None);
		else
		{
			vdat = FunctionCall3(&info->in.r.atts[i].typfunc,
								 vattr,
							ObjectIdGetDatum(info->in.r.atts[i].typelem),
							   Int32GetDatum(desc->attrs[i]->atttypmod));
			vsrc = DatumGetCString(vdat);

			/*
			 * no exceptions allowed
			 */
			value = info->in.r.atts[i].func(vsrc);
			pfree(vsrc);
			PyDict_SetItemString(dict, key, value);
			Py_DECREF(value);
		}
	}

	RESTORE_EXC();

	return dict;
}

/* initialization, some python variables function declared here
 */

/* interface to postgresql elog
 */
static PyObject *PLy_debug(PyObject *, PyObject *);
static PyObject *PLy_error(PyObject *, PyObject *);
static PyObject *PLy_fatal(PyObject *, PyObject *);
static PyObject *PLy_notice(PyObject *, PyObject *);

/* PLyPlanObject, PLyResultObject and SPI interface
 */
#define is_PLyPlanObject(x) ((x)->ob_type == &PLy_PlanType)
static PyObject *PLy_plan_new(void);
static void PLy_plan_dealloc(PyObject *);
static PyObject *PLy_plan_getattr(PyObject *, char *);
static PyObject *PLy_plan_status(PyObject *, PyObject *);

static PyObject *PLy_result_new(void);
static void PLy_result_dealloc(PyObject *);
static PyObject *PLy_result_getattr(PyObject *, char *);
static PyObject *PLy_result_fetch(PyObject *, PyObject *);
static PyObject *PLy_result_nrows(PyObject *, PyObject *);
static PyObject *PLy_result_status(PyObject *, PyObject *);
static int	PLy_result_length(PyObject *);
static PyObject *PLy_result_item(PyObject *, int);
static PyObject *PLy_result_slice(PyObject *, int, int);
static int	PLy_result_ass_item(PyObject *, int, PyObject *);
static int	PLy_result_ass_slice(PyObject *, int, int, PyObject *);


static PyObject *PLy_spi_prepare(PyObject *, PyObject *);
static PyObject *PLy_spi_execute(PyObject *, PyObject *);
static const char *PLy_spi_error_string(int);
static PyObject *PLy_spi_execute_query(char *query, int limit);
static PyObject *PLy_spi_execute_plan(PyObject *, PyObject *, int);
static PyObject *PLy_spi_execute_fetch_result(SPITupleTable *, int, int);


PyTypeObject PLy_PlanType = {
	PyObject_HEAD_INIT(NULL)
	0,							/* ob_size */
	"PLyPlan",					/* tp_name */
	sizeof(PLyPlanObject),		/* tp_size */
	0,							/* tp_itemsize */

	/*
	 * methods
	 */
	(destructor) PLy_plan_dealloc,		/* tp_dealloc */
	0,							/* tp_print */
	(getattrfunc) PLy_plan_getattr,		/* tp_getattr */
	0,							/* tp_setattr */
	0,							/* tp_compare */
	0,							/* tp_repr */
	0,							/* tp_as_number */
	0,							/* tp_as_sequence */
	0,							/* tp_as_mapping */
	0,							/* tp_hash */
	0,							/* tp_call */
	0,							/* tp_str */
	0,							/* tp_getattro */
	0,							/* tp_setattro */
	0,							/* tp_as_buffer */
	0,							/* tp_xxx4 */
	PLy_plan_doc,				/* tp_doc */
};

PyMethodDef PLy_plan_methods[] = {
	{"status", (PyCFunction) PLy_plan_status, METH_VARARGS, NULL},
	{NULL, NULL, 0, NULL}
};


PySequenceMethods PLy_result_as_sequence = {
	(inquiry) PLy_result_length,/* sq_length */
	(binaryfunc) 0,				/* sq_concat */
	(intargfunc) 0,				/* sq_repeat */
	(intargfunc) PLy_result_item,		/* sq_item */
	(intintargfunc) PLy_result_slice,	/* sq_slice */
	(intobjargproc) PLy_result_ass_item,		/* sq_ass_item */
	(intintobjargproc) PLy_result_ass_slice,	/* sq_ass_slice */
};

PyTypeObject PLy_ResultType = {
	PyObject_HEAD_INIT(NULL)
	0,							/* ob_size */
	"PLyResult",				/* tp_name */
	sizeof(PLyResultObject),	/* tp_size */
	0,							/* tp_itemsize */

	/*
	 * methods
	 */
	(destructor) PLy_result_dealloc,	/* tp_dealloc */
	0,							/* tp_print */
	(getattrfunc) PLy_result_getattr,	/* tp_getattr */
	0,							/* tp_setattr */
	0,							/* tp_compare */
	0,							/* tp_repr */
	0,							/* tp_as_number */
	&PLy_result_as_sequence,	/* tp_as_sequence */
	0,							/* tp_as_mapping */
	0,							/* tp_hash */
	0,							/* tp_call */
	0,							/* tp_str */
	0,							/* tp_getattro */
	0,							/* tp_setattro */
	0,							/* tp_as_buffer */
	0,							/* tp_xxx4 */
	PLy_result_doc,				/* tp_doc */
};

PyMethodDef PLy_result_methods[] = {
	{"fetch", (PyCFunction) PLy_result_fetch, METH_VARARGS, NULL,},
	{"nrows", (PyCFunction) PLy_result_nrows, METH_VARARGS, NULL},
	{"status", (PyCFunction) PLy_result_status, METH_VARARGS, NULL},
	{NULL, NULL, 0, NULL}
};


static PyMethodDef PLy_methods[] = {
	/*
	 * logging methods
	 */
	{"debug", PLy_debug, METH_VARARGS, NULL},
	{"error", PLy_error, METH_VARARGS, NULL},
	{"fatal", PLy_fatal, METH_VARARGS, NULL},
	{"notice", PLy_notice, METH_VARARGS, NULL},

	/*
	 * create a stored plan
	 */
	{"prepare", PLy_spi_prepare, METH_VARARGS, NULL},

	/*
	 * execute a plan or query
	 */
	{"execute", PLy_spi_execute, METH_VARARGS, NULL},

	{NULL, NULL, 0, NULL}
};


/* plan object methods
 */
PyObject *
PLy_plan_new(void)
{
	PLyPlanObject *ob;

	enter();

	if ((ob = PyObject_NEW(PLyPlanObject, &PLy_PlanType)) == NULL)
		return NULL;

	ob->plan = NULL;
	ob->nargs = 0;
	ob->types = NULL;
	ob->args = NULL;

	return (PyObject *) ob;
}


void
PLy_plan_dealloc(PyObject * arg)
{
	PLyPlanObject *ob = (PLyPlanObject *) arg;

	enter();

	if (ob->plan)
	{
		/*
		 * free the plan... pfree(ob->plan);
		 *
		 * FIXME -- leaks saved plan on object destruction.  can this be
		 * avoided?
		 */
	}
	if (ob->types)
		PLy_free(ob->types);
	if (ob->args)
	{
		int			i;

		for (i = 0; i < ob->nargs; i++)
			PLy_typeinfo_dealloc(&ob->args[i]);
		PLy_free(ob->args);
	}

	PyMem_DEL(arg);

	leave();
}


PyObject *
PLy_plan_getattr(PyObject * self, char *name)
{
	return Py_FindMethod(PLy_plan_methods, self, name);
}

PyObject *
PLy_plan_status(PyObject * self, PyObject * args)
{
	if (PyArg_ParseTuple(args, ""))
	{
		Py_INCREF(Py_True);
		return Py_True;
		/* return PyInt_FromLong(self->status); */
	}
	PyErr_SetString(PLy_exc_error, "plan.status() takes no arguments");
	return NULL;
}



/* result object methods
 */

static PyObject *
PLy_result_new(void)
{
	PLyResultObject *ob;

	enter();

	if ((ob = PyObject_NEW(PLyResultObject, &PLy_ResultType)) == NULL)
		return NULL;

	/* ob->tuples = NULL; */

	Py_INCREF(Py_None);
	ob->status = Py_None;
	ob->nrows = PyInt_FromLong(-1);
	ob->rows = PyList_New(0);

	return (PyObject *) ob;
}

static void
PLy_result_dealloc(PyObject * arg)
{
	PLyResultObject *ob = (PLyResultObject *) arg;

	enter();

	Py_XDECREF(ob->nrows);
	Py_XDECREF(ob->rows);
	Py_XDECREF(ob->status);

	PyMem_DEL(ob);
}

static PyObject *
PLy_result_getattr(PyObject * self, char *attr)
{
	return NULL;
}

static PyObject *
PLy_result_fetch(PyObject * self, PyObject * args)
{
	return NULL;
}

static PyObject *
PLy_result_nrows(PyObject * self, PyObject * args)
{
	PLyResultObject *ob = (PLyResultObject *) self;

	Py_INCREF(ob->nrows);
	return ob->nrows;
}

static PyObject *
PLy_result_status(PyObject * self, PyObject * args)
{
	PLyResultObject *ob = (PLyResultObject *) self;

	Py_INCREF(ob->status);
	return ob->status;
}

int
PLy_result_length(PyObject * arg)
{
	PLyResultObject *ob = (PLyResultObject *) arg;

	return PyList_Size(ob->rows);
}

PyObject *
PLy_result_item(PyObject * arg, int idx)
{
	PyObject   *rv;
	PLyResultObject *ob = (PLyResultObject *) arg;

	rv = PyList_GetItem(ob->rows, idx);
	if (rv != NULL)
		Py_INCREF(rv);
	return rv;
}

int
PLy_result_ass_item(PyObject * arg, int idx, PyObject * item)
{
	int			rv;
	PLyResultObject *ob = (PLyResultObject *) arg;

	Py_INCREF(item);
	rv = PyList_SetItem(ob->rows, idx, item);
	return rv;
}

PyObject *
PLy_result_slice(PyObject * arg, int lidx, int hidx)
{
	PyObject   *rv;
	PLyResultObject *ob = (PLyResultObject *) arg;

	rv = PyList_GetSlice(ob->rows, lidx, hidx);
	if (rv == NULL)
		return NULL;
	Py_INCREF(rv);
	return rv;
}

int
PLy_result_ass_slice(PyObject * arg, int lidx, int hidx, PyObject * slice)
{
	int			rv;
	PLyResultObject *ob = (PLyResultObject *) arg;

	rv = PyList_SetSlice(ob->rows, lidx, hidx, slice);
	return rv;
}

/* SPI interface
 */
PyObject *
PLy_spi_prepare(PyObject * self, PyObject * args)
{
	DECLARE_EXC();
	PLyPlanObject *plan;
	PyObject   *list = NULL;
	PyObject   *volatile optr = NULL;
	char	   *query;

	enter();

	if (!PyArg_ParseTuple(args, "s|O", &query, &list))
	{
		PyErr_SetString(PLy_exc_spi_error,
						"Invalid arguments for plpy.prepare()");
		return NULL;
	}

	if ((list) && (!PySequence_Check(list)))
	{
		PyErr_SetString(PLy_exc_spi_error,
				 "Second argument in plpy.prepare() must be a sequence");
		return NULL;
	}


	if ((plan = (PLyPlanObject *) PLy_plan_new()) == NULL)
		return NULL;

	SAVE_EXC();
	if (TRAP_EXC())
	{
		RESTORE_EXC();
		Py_DECREF(plan);
		Py_XDECREF(optr);
		if (!PyErr_Occurred())
			PyErr_SetString(PLy_exc_spi_error,
							"Unknown error in PLy_spi_prepare.");
		return NULL;
	}

	if (list != NULL)
	{
		int			nargs,
					i;


		nargs = PySequence_Length(list);
		if (nargs > 0)
		{
			plan->nargs = nargs;
			plan->types = PLy_malloc(sizeof(Oid) * nargs);
			plan->values = PLy_malloc(sizeof(Datum) * nargs);
			plan->args = PLy_malloc(sizeof(PLyTypeInfo) * nargs);

			/*
			 * the other loop might throw an exception, if PLyTypeInfo
			 * member isn't properly initialized the Py_DECREF(plan) will
			 * go boom
			 */
			for (i = 0; i < nargs; i++)
			{
				PLy_typeinfo_init(&plan->args[i]);
				plan->values[i] = (Datum) NULL;
			}

			for (i = 0; i < nargs; i++)
			{
				char	   *sptr;
				HeapTuple	typeTup;
				Form_pg_type typeStruct;

				optr = PySequence_GetItem(list, i);
				if (!PyString_Check(optr))
				{
					PyErr_SetString(PLy_exc_spi_error,
									"Type names must be strings.");
					RAISE_EXC(1);
				}
				sptr = PyString_AsString(optr);
				typeTup = SearchSysCache(TYPENAME, PointerGetDatum(sptr),
										 0, 0, 0);
				if (!HeapTupleIsValid(typeTup))
				{
					PLy_exception_set(PLy_exc_spi_error,
									"Cache lookup for type `%s' failed.",
									  sptr);
					RAISE_EXC(1);
				}

				Py_DECREF(optr);
				optr = NULL;	/* this is important */

				plan->types[i] = typeTup->t_data->t_oid;
				typeStruct = (Form_pg_type) GETSTRUCT(typeTup);
				if (typeStruct->typrelid == InvalidOid)
					PLy_output_datum_func(&plan->args[i], typeStruct);
				else
				{
					PyErr_SetString(PLy_exc_spi_error,
							 "tuples not handled in plpy.prepare, yet.");
					RAISE_EXC(1);
				}
				ReleaseSysCache(typeTup);
			}
		}
	}

	plan->plan = SPI_prepare(query, plan->nargs, plan->types);
	if (plan->plan == NULL)
	{
		PLy_exception_set(PLy_exc_spi_error,
					 "Unable to prepare plan. SPI_prepare failed -- %s.",
						  PLy_spi_error_string(SPI_result));
		RAISE_EXC(1);
	}

	plan->plan = SPI_saveplan(plan->plan);
	if (plan->plan == NULL)
	{
		PLy_exception_set(PLy_exc_spi_error,
					   "Unable to save plan. SPI_saveplan failed -- %s.",
						  PLy_spi_error_string(SPI_result));
		RAISE_EXC(1);
	}

	RESTORE_EXC();

	return (PyObject *) plan;
}

/* execute(query="select * from foo", limit=5)
 * execute(plan=plan, values=(foo, bar), limit=5)
 */
PyObject *
PLy_spi_execute(PyObject * self, PyObject * args)
{
	char	   *query;
	PyObject   *plan;
	PyObject   *list = NULL;
	int			limit = 0;

	enter();

#if 0

	/*
	 * there should - hahaha - be an python exception set so just return
	 * NULL.  FIXME -- is this needed?
	 */
	if (PLy_restart_in_progress)
		return NULL;
#endif

	if (PyArg_ParseTuple(args, "s|i", &query, &limit))
		return PLy_spi_execute_query(query, limit);

	PyErr_Clear();

	if ((PyArg_ParseTuple(args, "O|Oi", &plan, &list, &limit)) &&
		(is_PLyPlanObject(plan)))
	{
		PyObject   *rv = PLy_spi_execute_plan(plan, list, limit);

		return rv;
	}

	PyErr_SetString(PLy_exc_error, "Expected a query or plan.");
	return NULL;
}

PyObject *
PLy_spi_execute_plan(PyObject * ob, PyObject * list, int limit)
{
	DECLARE_EXC();
	volatile int nargs;
	int			i,
				rv;
	PLyPlanObject *plan;

	enter();

	if (list != NULL)
	{
		if ((!PySequence_Check(list)) || (PyString_Check(list)))
		{
			char	   *msg = "plpy.execute() takes a sequence as its second argument";

			PyErr_SetString(PLy_exc_spi_error, msg);
			return NULL;
		}
		nargs = PySequence_Length(list);
	}
	else
		nargs = 0;

	plan = (PLyPlanObject *) ob;

	if (nargs != plan->nargs)
	{
		char	   *sv;

		PyObject   *so = PyObject_Str(list);

		sv = PyString_AsString(so);
		PLy_exception_set(PLy_exc_spi_error,
						  "Expected sequence of %d arguments, got %d. %s",
						  plan->nargs, nargs, sv);
		Py_DECREF(so);

		return NULL;
	}

	SAVE_EXC();
	if (TRAP_EXC())
	{
		RESTORE_EXC();

		/*
		 * cleanup plan->values array
		 */
		for (i = 0; i < nargs; i++)
		{
			if (!plan->args[i].out.d.typbyval &&
				(plan->values[i] != (Datum) NULL))
			{
				pfree(DatumGetPointer(plan->values[i]));
				plan->values[i] = (Datum) NULL;
			}
		}

		if (!PyErr_Occurred())
			PyErr_SetString(PLy_exc_error,
							"Unknown error in PLy_spi_execute_plan");
		return NULL;
	}

	if (nargs)
	{
		for (i = 0; i < nargs; i++)
		{
			PyObject   *elem,
					   *so;
			char	   *sv;

			elem = PySequence_GetItem(list, i);
			so = PyObject_Str(elem);
			sv = PyString_AsString(so);

			/*
			 * FIXME -- if this can elog, we have leak
			 */
			plan->values[i] = FunctionCall3(&(plan->args[i].out.d.typfunc),
											CStringGetDatum(sv),
						   ObjectIdGetDatum(plan->args[i].out.d.typelem),
											Int32GetDatum(-1));

			Py_DECREF(so);
			Py_DECREF(elem);
		}
	}

	rv = SPI_execp(plan->plan, plan->values, NULL, limit);
	RESTORE_EXC();

	for (i = 0; i < nargs; i++)
	{
		if (!plan->args[i].out.d.typbyval &&
			(plan->values[i] != (Datum) NULL))
		{
			pfree(DatumGetPointer(plan->values[i]));
			plan->values[i] = (Datum) NULL;
		}
	}

	if (rv < 0)
	{
		PLy_exception_set(PLy_exc_spi_error,
					   "Unable to execute plan.  SPI_execp failed -- %s",
						  PLy_spi_error_string(rv));
		return NULL;
	}

	return PLy_spi_execute_fetch_result(SPI_tuptable, SPI_processed, rv);
}

PyObject *
PLy_spi_execute_query(char *query, int limit)
{
	DECLARE_EXC();
	int			rv;

	SAVE_EXC();
	if (TRAP_EXC())
	{
		RESTORE_EXC();

		if ((!PLy_restart_in_progress) && (!PyErr_Occurred()))
			PyErr_SetString(PLy_exc_spi_error,
							"Unknown error in PLy_spi_execute_query.");
		return NULL;
	}

	rv = SPI_exec(query, limit);
	RESTORE_EXC();

	if (rv < 0)
	{
		PLy_exception_set(PLy_exc_spi_error,
					   "Unable to execute query.  SPI_exec failed -- %s",
						  PLy_spi_error_string(rv));
		return NULL;
	}

	return PLy_spi_execute_fetch_result(SPI_tuptable, SPI_processed, rv);
}

PyObject *
PLy_spi_execute_fetch_result(SPITupleTable *tuptable, int rows, int status)
{
	PLyResultObject *result;

	enter();

	result = (PLyResultObject *) PLy_result_new();
	Py_DECREF(result->status);
	result->status = PyInt_FromLong(status);

	if (status == SPI_OK_UTILITY)
	{
		Py_DECREF(result->nrows);
		result->nrows = PyInt_FromLong(0);
	}
	else if (status != SPI_OK_SELECT)
	{
		Py_DECREF(result->nrows);
		result->nrows = PyInt_FromLong(rows);
	}
	else
	{
		DECLARE_EXC();
		PLyTypeInfo args;
		int			i;

		PLy_typeinfo_init(&args);
		Py_DECREF(result->nrows);
		result->nrows = PyInt_FromLong(rows);

		SAVE_EXC();
		if (TRAP_EXC())
		{
			RESTORE_EXC();

			if (!PyErr_Occurred())
				PyErr_SetString(PLy_exc_error,
						"Unknown error in PLy_spi_execute_fetch_result");
			Py_DECREF(result);
			PLy_typeinfo_dealloc(&args);
			return NULL;
		}

		if (rows)
		{
			Py_DECREF(result->rows);
			result->rows = PyList_New(rows);

			PLy_input_tuple_funcs(&args, tuptable->tupdesc);
			for (i = 0; i < rows; i++)
			{
				PyObject   *row = PLyDict_FromTuple(&args, tuptable->vals[i],
													tuptable->tupdesc);

				PyList_SetItem(result->rows, i, row);
			}
			PLy_typeinfo_dealloc(&args);
		}
		RESTORE_EXC();
	}

	return (PyObject *) result;
}

const char *
PLy_spi_error_string(int code)
{
	switch (code)
	{
		case SPI_ERROR_TYPUNKNOWN:
			return "SPI_ERROR_TYPUNKNOWN";
		case SPI_ERROR_NOOUTFUNC:
			return "SPI_ERROR_NOOUTFUNC";
		case SPI_ERROR_NOATTRIBUTE:
			return "SPI_ERROR_NOATTRIBUTE";
		case SPI_ERROR_TRANSACTION:
			return "SPI_ERROR_TRANSACTION";
		case SPI_ERROR_PARAM:
			return "SPI_ERROR_PARAM";
		case SPI_ERROR_ARGUMENT:
			return "SPI_ERROR_ARGUMENT";
		case SPI_ERROR_CURSOR:
			return "SPI_ERROR_CURSOR";
		case SPI_ERROR_UNCONNECTED:
			return "SPI_ERROR_UNCONNECTED";
		case SPI_ERROR_OPUNKNOWN:
			return "SPI_ERROR_OPUNKNOWN";
		case SPI_ERROR_COPY:
			return "SPI_ERROR_COPY";
		case SPI_ERROR_CONNECT:
			return "SPI_ERROR_CONNECT";
	}
	return "Unknown or Invalid code";
}

/* language handler and interpreter initialization
 */

void
PLy_init_all(void)
{
	static volatile int init_active = 0;

	enter();

	if (init_active)
		elog(FATAL, "plpython: Initialization of language module failed.");
	init_active = 1;

	Py_Initialize();
	PLy_init_interp();
	PLy_init_plpy();
	PLy_init_safe_interp();
	if (PyErr_Occurred())
		PLy_elog(FATAL, "Untrapped error in initialization.");
	PLy_procedure_cache = PyDict_New();
	if (PLy_procedure_cache == NULL)
		PLy_elog(ERROR, "Unable to create procedure cache.");

	PLy_first_call = 0;

	leave();
}

void
PLy_init_interp(void)
{
	PyObject   *mainmod;

	enter();

	mainmod = PyImport_AddModule("__main__");
	if ((mainmod == NULL) || (PyErr_Occurred()))
		PLy_elog(ERROR, "Unable to import '__main__' module.");
	Py_INCREF(mainmod);
	PLy_interp_globals = PyModule_GetDict(mainmod);
	Py_DECREF(mainmod);
	if ((PLy_interp_globals == NULL) || (PyErr_Occurred()))
		PLy_elog(ERROR, "Unable to initialize globals.");
}

void
PLy_init_plpy(void)
{
	PyObject   *main_mod,
			   *main_dict,
			   *plpy_mod;
	PyObject   *plpy,
			   *plpy_dict;

	enter();

	/*
	 * initialize plpy module
	 */
	PLy_PlanType.ob_type = PLy_ResultType.ob_type = &PyType_Type;
	plpy = Py_InitModule("plpy", PLy_methods);
	plpy_dict = PyModule_GetDict(plpy);

	/* PyDict_SetItemString(plpy, "PlanType", (PyObject *) &PLy_PlanType); */

	PLy_exc_error = PyErr_NewException("plpy.Error", NULL, NULL);
	PLy_exc_fatal = PyErr_NewException("plpy.Fatal", NULL, NULL);
	PLy_exc_spi_error = PyErr_NewException("plpy.SPIError", NULL, NULL);
	PyDict_SetItemString(plpy_dict, "Error", PLy_exc_error);
	PyDict_SetItemString(plpy_dict, "Fatal", PLy_exc_fatal);
	PyDict_SetItemString(plpy_dict, "SPIError", PLy_exc_spi_error);

	/*
	 * initialize main module, and add plpy
	 */
	main_mod = PyImport_AddModule("__main__");
	main_dict = PyModule_GetDict(main_mod);
	plpy_mod = PyImport_AddModule("plpy");
	PyDict_SetItemString(main_dict, "plpy", plpy_mod);
	if (PyErr_Occurred())
		elog(ERROR, "Unable to init plpy.");
}

void
PLy_init_safe_interp(void)
{
	PyObject   *rmod;
	char	   *rname = "rexec";
	int			i,
				imax;

	enter();

	rmod = PyImport_ImportModuleEx(rname, PLy_interp_globals,
								   PLy_interp_globals, Py_None);
	if ((rmod == NULL) || (PyErr_Occurred()))
		PLy_elog(ERROR, "Unable to import %s.", rname);
	PyDict_SetItemString(PLy_interp_globals, rname, rmod);
	PLy_interp_safe = rmod;

	imax = sizeof(PLy_importable_modules_list) / sizeof(char *);
	PLy_importable_modules = PyTuple_New(imax);
	for (i = 0; i < imax; i++)
	{
		PyObject   *m = PyString_FromString(PLy_importable_modules_list[i]);

		PyTuple_SetItem(PLy_importable_modules, i, m);
	}

	PLy_interp_safe_globals = PyDict_New();
	if (PLy_interp_safe_globals == NULL)
		PLy_elog(ERROR, "Unable to create shared global dictionary.");

}


/* the python interface to the elog function
 * don't confuse these with PLy_elog
 */
static PyObject *PLy_log(int, PyObject *, PyObject *);

PyObject *
PLy_debug(PyObject * self, PyObject * args)
{
	return PLy_log(DEBUG, self, args);
}

PyObject *
PLy_error(PyObject * self, PyObject * args)
{
	return PLy_log(ERROR, self, args);
}

PyObject *
PLy_fatal(PyObject * self, PyObject * args)
{
	return PLy_log(FATAL, self, args);
}

PyObject *
PLy_notice(PyObject * self, PyObject * args)
{
	return PLy_log(NOTICE, self, args);
}


PyObject *
PLy_log(volatile int level, PyObject * self, PyObject * args)
{
	DECLARE_EXC();
	PyObject   *so;
	char	   *volatile sv;

	enter();

	if (args == NULL)
		elog(NOTICE, "plpython, args is NULL in %s", __FUNCTION__);

	so = PyObject_Str(args);
	if ((so == NULL) || ((sv = PyString_AsString(so)) == NULL))
	{
		level = ERROR;
		sv = "Unable to parse error message in `plpy.elog'";
	}

	/*
	 * returning NULL here causes the python interpreter to bail. when
	 * control passes back into plpython_*_handler, we check for python
	 * exceptions and do the actual elog call.	actually PLy_elog.
	 */
	if (level == ERROR)
	{
		PyErr_SetString(PLy_exc_error, sv);
		return NULL;
	}
	else if (level >= FATAL)
	{
		PyErr_SetString(PLy_exc_fatal, sv);
		return NULL;
	}

	/*
	 * ok, this is a NOTICE, or DEBUG message
	 *
	 * but just in case DON'T long jump out of the interpreter!
	 */
	SAVE_EXC();
	if (TRAP_EXC())
	{
		RESTORE_EXC();

		Py_XDECREF(so);

		/*
		 * the real error message should already be written into the
		 * postgresql log, no?	whatever, this shouldn't happen so die
		 * hideously.
		 */
		elog(FATAL, "plpython: Aiieee, elog threw an unknown exception!");
		return NULL;
	}

	elog(level, sv);

	RESTORE_EXC();

	Py_XDECREF(so);
	Py_INCREF(Py_None);

	/*
	 * return a legal object so the interpreter will continue on its merry
	 * way
	 */
	return Py_None;
}


/* output a python traceback/exception via the postgresql elog
 * function.  not pretty.
 */

static char *PLy_traceback(int *);
static char *PLy_vprintf(const char *fmt, va_list ap);
static char *PLy_printf(const char *fmt,...);

void
PLy_exception_set(PyObject * exc, const char *fmt,...)
{
	char		buf[1024];
	va_list		ap;

	va_start(ap, fmt);
	vsnprintf(buf, sizeof(buf), fmt, ap);
	va_end(ap);

	PyErr_SetString(exc, buf);
}

void
PLy_elog(int elevel, const char *fmt,...)
{
	DECLARE_EXC();
	va_list		ap;
	char	   *xmsg,
			   *emsg;
	int			xlevel;

	enter();

	xmsg = PLy_traceback(&xlevel);

	va_start(ap, fmt);
	emsg = PLy_vprintf(fmt, ap);
	va_end(ap);

	SAVE_EXC();
	if (TRAP_EXC())
	{
		RESTORE_EXC();
		mark();

		/*
		 * elog called siglongjmp. cleanup, restore and reraise
		 */
		PLy_restart_in_progress += 1;
		PLy_free(emsg);
		PLy_free(xmsg);
		RERAISE_EXC();
	}

	if (xmsg)
	{
		elog(elevel, "plpython: %s\n%s", emsg, xmsg);
		PLy_free(xmsg);
	}
	else
		elog(elevel, "plpython: %s", emsg);
	PLy_free(emsg);

	leave();

	RESTORE_EXC();
}

char *
PLy_traceback(int *xlevel)
{
	PyObject   *e,
			   *v,
			   *tb;
	PyObject   *eob,
			   *vob = NULL;
	char	   *vstr,
			   *estr,
			   *xstr = NULL;

	enter();

	/*
	 * get the current exception
	 */
	PyErr_Fetch(&e, &v, &tb);

	/*
	 * oops, no exception, return
	 */
	if (e == NULL)
	{
		*xlevel = NOTICE;
		return NULL;
	}

	PyErr_NormalizeException(&e, &v, &tb);

	eob = PyObject_Str(e);
	if ((v) && ((vob = PyObject_Str(v)) != NULL))
		vstr = PyString_AsString(vob);
	else
		vstr = "Unknown";

	estr = PyString_AsString(eob);
	xstr = PLy_printf("%s: %s", estr, vstr);

	Py_DECREF(eob);
	Py_XDECREF(vob);

	/*
	 * intuit an appropriate error level for based on the exception type
	 */
	if ((PLy_exc_error) && (PyErr_GivenExceptionMatches(e, PLy_exc_error)))
		*xlevel = ERROR;
	else if ((PLy_exc_fatal) && (PyErr_GivenExceptionMatches(e, PLy_exc_fatal)))
		*xlevel = FATAL;
	else
		*xlevel = ERROR;

	leave();

	return xstr;
}

char *
PLy_printf(const char *fmt,...)
{
	va_list		ap;
	char	   *emsg;

	va_start(ap, fmt);
	emsg = PLy_vprintf(fmt, ap);
	va_end(ap);
	return emsg;
}

char *
PLy_vprintf(const char *fmt, va_list ap)
{
	size_t		blen;
	int			bchar,
				tries = 2;
	char	   *buf;

	blen = strlen(fmt) * 2;
	if (blen < 256)
		blen = 256;
	buf = PLy_malloc(blen * sizeof(char));

	while (1)
	{
		bchar = vsnprintf(buf, blen, fmt, ap);
		if ((bchar > 0) && (bchar < blen))
			return buf;
		if (tries-- <= 0)
			break;
		if (blen > 0)
			blen = bchar + 1;
		else
			blen *= 2;
		buf = PLy_realloc(buf, blen);
	}
	PLy_free(buf);
	return NULL;
}

/* python module code
 */


/* some dumb utility functions
 */

void *
PLy_malloc(size_t bytes)
{
	void	   *ptr = malloc(bytes);

	if (ptr == NULL)
		elog(FATAL, "plpython: Memory exhausted.");
	return ptr;
}

void *
PLy_realloc(void *optr, size_t bytes)
{
	void	   *nptr = realloc(optr, bytes);

	if (nptr == NULL)
		elog(FATAL, "plpython: Memory exhausted.");
	return nptr;
}

/* define this away
 */
void
PLy_free(void *ptr)
{
	free(ptr);
}