/**********************************************************************
 * pl_handler.c		- Handler for the PL/pgSQL
 *			  procedural language
 *
 * IDENTIFICATION
 *	  $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_handler.c,v 1.25 2005/03/29 00:17:23 tgl Exp $
 *
 *	  This software is copyrighted by Jan Wieck - Hamburg.
 *
 *	  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.
 *
 **********************************************************************/

#include "plpgsql.h"
#include "pl.tab.h"

#include "access/heapam.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"

extern DLLIMPORT bool check_function_bodies;

static bool	plpgsql_firstcall = true;

static void plpgsql_init_all(void);


/*
 * plpgsql_init()			- postmaster-startup safe initialization
 *
 * DO NOT make this static --- it has to be callable by preload
 */
void
plpgsql_init(void)
{
	/* Do initialization only once */
	if (!plpgsql_firstcall)
		return;

	plpgsql_HashTableInit();
	RegisterXactCallback(plpgsql_xact_cb, NULL);
	plpgsql_firstcall = false;
}

/*
 * plpgsql_init_all()		- Initialize all
 */
static void
plpgsql_init_all(void)
{
	/* Execute any postmaster-startup safe initialization */
	plpgsql_init();

	/*
	 * Any other initialization that must be done each time a new backend
	 * starts -- currently none
	 */
}

/* ----------
 * plpgsql_call_handler
 *
 * The PostgreSQL function manager and trigger manager
 * call this function for execution of PL/pgSQL procedures.
 * ----------
 */
PG_FUNCTION_INFO_V1(plpgsql_call_handler);

Datum
plpgsql_call_handler(PG_FUNCTION_ARGS)
{
	PLpgSQL_function *func;
	Datum		retval;
	int			rc;

	/* perform initialization */
	plpgsql_init_all();

	/*
	 * Connect to SPI manager
	 */
	if ((rc = SPI_connect()) != SPI_OK_CONNECT)
		elog(ERROR, "SPI_connect failed: %s", SPI_result_code_string(rc));

	/* Find or compile the function */
	func = plpgsql_compile(fcinfo, false);

	/*
	 * Determine if called as function or trigger and call appropriate
	 * subhandler
	 */
	if (CALLED_AS_TRIGGER(fcinfo))
		retval = PointerGetDatum(plpgsql_exec_trigger(func,
									   (TriggerData *) fcinfo->context));
	else
		retval = plpgsql_exec_function(func, fcinfo);

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

	return retval;
}

/* ----------
 * plpgsql_validator
 *
 * This function attempts to validate a PL/pgSQL function at
 * CREATE FUNCTION time.
 * ----------
 */
PG_FUNCTION_INFO_V1(plpgsql_validator);

Datum
plpgsql_validator(PG_FUNCTION_ARGS)
{
	Oid			funcoid = PG_GETARG_OID(0);
	HeapTuple	tuple;
	Form_pg_proc proc;
	char		functyptype;
	bool		istrigger = false;
	bool		haspolyresult;
	bool		haspolyarg;
	int			i;

	/* perform initialization */
	plpgsql_init_all();

	/* Get the new function's pg_proc entry */
	tuple = SearchSysCache(PROCOID,
						   ObjectIdGetDatum(funcoid),
						   0, 0, 0);
	if (!HeapTupleIsValid(tuple))
		elog(ERROR, "cache lookup failed for function %u", funcoid);
	proc = (Form_pg_proc) GETSTRUCT(tuple);

	functyptype = get_typtype(proc->prorettype);

	/* Disallow pseudotype result */
	/* except for TRIGGER, RECORD, VOID, ANYARRAY, or ANYELEMENT */
	if (functyptype == 'p')
	{
		/* we assume OPAQUE with no arguments means a trigger */
		if (proc->prorettype == TRIGGEROID ||
			(proc->prorettype == OPAQUEOID && proc->pronargs == 0))
			istrigger = true;
		else if (proc->prorettype == ANYARRAYOID ||
				 proc->prorettype == ANYELEMENTOID)
			haspolyresult = true;
		else if (proc->prorettype != RECORDOID &&
				 proc->prorettype != VOIDOID)
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
					 errmsg("plpgsql functions cannot return type %s",
							format_type_be(proc->prorettype))));
	}

	/* Disallow pseudotypes in arguments */
	/* except for ANYARRAY or ANYELEMENT */
	haspolyarg = false;
	for (i = 0; i < proc->pronargs; i++)
	{
		if (get_typtype(proc->proargtypes.values[i]) == 'p')
		{
			if (proc->proargtypes.values[i] == ANYARRAYOID ||
				proc->proargtypes.values[i] == ANYELEMENTOID)
				haspolyarg = true;
			else
				ereport(ERROR,
						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
						 errmsg("plpgsql functions cannot take type %s",
								format_type_be(proc->proargtypes.values[i]))));
		}
	}

	/* Postpone body checks if !check_function_bodies */
	if (check_function_bodies)
	{
		FunctionCallInfoData fake_fcinfo;
		FmgrInfo	flinfo;
		TriggerData trigdata;
		int			rc;

		/*
		 * Connect to SPI manager (is this needed for compilation?)
		 */
		if ((rc = SPI_connect()) != SPI_OK_CONNECT)
			elog(ERROR, "SPI_connect failed: %s", SPI_result_code_string(rc));

		/*
		 * Set up a fake fcinfo with just enough info to satisfy
		 * plpgsql_compile().
		 */
		MemSet(&fake_fcinfo, 0, sizeof(fake_fcinfo));
		MemSet(&flinfo, 0, sizeof(flinfo));
		fake_fcinfo.flinfo = &flinfo;
		flinfo.fn_oid = funcoid;
		flinfo.fn_mcxt = CurrentMemoryContext;
		if (istrigger)
		{
			MemSet(&trigdata, 0, sizeof(trigdata));
			trigdata.type = T_TriggerData;
			fake_fcinfo.context = (Node *) &trigdata;
		}

		/* Test-compile the function */
		plpgsql_compile(&fake_fcinfo, true);

		/*
		 * Disconnect from SPI manager
		 */
		if ((rc = SPI_finish()) != SPI_OK_FINISH)
			elog(ERROR, "SPI_finish failed: %s", SPI_result_code_string(rc));
	}

	ReleaseSysCache(tuple);

	PG_RETURN_VOID();
}
