plperl.c

PostgreSQL7.4.6 for Linux

				XPUSHs(&PL_sv_undef);
			else
			{
				char	   *tmp;

				tmp = DatumGetCString(FunctionCall3(&(desc->arg_out_func[i]),
													fcinfo->arg[i],
								 ObjectIdGetDatum(desc->arg_out_elem[i]),
													Int32GetDatum(-1)));
				XPUSHs(sv_2mortal(newSVpv(tmp, 0)));
				pfree(tmp);
			}
		}
	}
	PUTBACK;

	/* Do NOT use G_KEEPERR here */
	count = perl_call_sv(desc->reference, G_SCALAR | G_EVAL);

	SPAGAIN;

	if (count != 1)
	{
		PUTBACK;
		FREETMPS;
		LEAVE;
		elog(ERROR, "didn't get a return item from function");
	}

	if (SvTRUE(ERRSV))
	{
		POPs;
		PUTBACK;
		FREETMPS;
		LEAVE;
		elog(ERROR, "error from function: %s", SvPV(ERRSV, PL_na));
	}

	retval = newSVsv(POPs);

	PUTBACK;
	FREETMPS;
	LEAVE;

	return retval;
}


/**********************************************************************
 * plperl_func_handler()		- Handler for regular function calls
 **********************************************************************/
static Datum
plperl_func_handler(PG_FUNCTION_ARGS)
{
	plperl_proc_desc *prodesc;
	SV		   *perlret;
	Datum		retval;

	/* Find or compile the function */
	prodesc = compile_plperl_function(fcinfo->flinfo->fn_oid, false);

	/************************************************************
	 * Call the Perl function
	 ************************************************************/
	perlret = plperl_call_perl_func(prodesc, fcinfo);

	/************************************************************
	 * 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, "SPI_finish() failed");

	if (!(perlret && SvOK(perlret)))
	{
		/* return NULL if Perl code returned undef */
		retval = (Datum) 0;
		fcinfo->isnull = true;
	}
	else
	{
		retval = FunctionCall3(&prodesc->result_in_func,
							   PointerGetDatum(SvPV(perlret, PL_na)),
							   ObjectIdGetDatum(prodesc->result_in_elem),
							   Int32GetDatum(-1));
	}

	SvREFCNT_dec(perlret);

	return retval;
}


/**********************************************************************
 * compile_plperl_function	- compile (or hopefully just look up) function
 **********************************************************************/
static plperl_proc_desc *
compile_plperl_function(Oid fn_oid, bool is_trigger)
{
	HeapTuple	procTup;
	Form_pg_proc procStruct;
	char		internal_proname[64];
	int			proname_len;
	plperl_proc_desc *prodesc = NULL;
	int			i;

	/* We'll need the pg_proc tuple in any case... */
	procTup = SearchSysCache(PROCOID,
							 ObjectIdGetDatum(fn_oid),
							 0, 0, 0);
	if (!HeapTupleIsValid(procTup))
		elog(ERROR, "cache lookup failed for function %u", fn_oid);
	procStruct = (Form_pg_proc) GETSTRUCT(procTup);

	/************************************************************
	 * Build our internal proc name from the functions Oid
	 ************************************************************/
	if (!is_trigger)
		sprintf(internal_proname, "__PLPerl_proc_%u", fn_oid);
	else
		sprintf(internal_proname, "__PLPerl_proc_%u_trigger", fn_oid);
	proname_len = strlen(internal_proname);

	/************************************************************
	 * Lookup the internal proc name in the hashtable
	 ************************************************************/
	if (hv_exists(plperl_proc_hash, internal_proname, proname_len))
	{
		bool		uptodate;

		prodesc = (plperl_proc_desc *) SvIV(*hv_fetch(plperl_proc_hash,
									  internal_proname, proname_len, 0));

		/************************************************************
		 * If it's present, must check whether it's still up to date.
		 * This is needed because CREATE OR REPLACE FUNCTION can modify the
		 * function's pg_proc entry without changing its OID.
		 ************************************************************/
		uptodate = (prodesc->fn_xmin == HeapTupleHeaderGetXmin(procTup->t_data) &&
			prodesc->fn_cmin == HeapTupleHeaderGetCmin(procTup->t_data));

		if (!uptodate)
		{
			/* need we delete old entry? */
			prodesc = NULL;
		}
	}

	/************************************************************
	 * If we haven't found it in the hashtable, we analyze
	 * the functions arguments and returntype and store
	 * the in-/out-functions in the prodesc block and create
	 * a new hashtable entry for it.
	 *
	 * Then we load the procedure into the Perl interpreter.
	 ************************************************************/
	if (prodesc == NULL)
	{
		HeapTuple	langTup;
		HeapTuple	typeTup;
		Form_pg_language langStruct;
		Form_pg_type typeStruct;
		char	   *proc_source;

		/************************************************************
		 * Allocate a new procedure description block
		 ************************************************************/
		prodesc = (plperl_proc_desc *) malloc(sizeof(plperl_proc_desc));
		if (prodesc == NULL)
			ereport(ERROR,
					(errcode(ERRCODE_OUT_OF_MEMORY),
					 errmsg("out of memory")));
		MemSet(prodesc, 0, sizeof(plperl_proc_desc));
		prodesc->proname = strdup(internal_proname);
		prodesc->fn_xmin = HeapTupleHeaderGetXmin(procTup->t_data);
		prodesc->fn_cmin = HeapTupleHeaderGetCmin(procTup->t_data);

		/************************************************************
		 * Lookup the pg_language tuple by Oid
		 ************************************************************/
		langTup = SearchSysCache(LANGOID,
								 ObjectIdGetDatum(procStruct->prolang),
								 0, 0, 0);
		if (!HeapTupleIsValid(langTup))
		{
			free(prodesc->proname);
			free(prodesc);
			elog(ERROR, "cache lookup failed for language %u",
				 procStruct->prolang);
		}
		langStruct = (Form_pg_language) GETSTRUCT(langTup);
		prodesc->lanpltrusted = langStruct->lanpltrusted;
		ReleaseSysCache(langTup);

		/************************************************************
		 * Get the required information for input conversion of the
		 * return value.
		 ************************************************************/
		if (!is_trigger)
		{
			typeTup = SearchSysCache(TYPEOID,
								ObjectIdGetDatum(procStruct->prorettype),
									 0, 0, 0);
			if (!HeapTupleIsValid(typeTup))
			{
				free(prodesc->proname);
				free(prodesc);
				elog(ERROR, "cache lookup failed for type %u",
					 procStruct->prorettype);
			}
			typeStruct = (Form_pg_type) GETSTRUCT(typeTup);

			/* Disallow pseudotype result, except VOID */
			if (typeStruct->typtype == 'p')
			{
				if (procStruct->prorettype == VOIDOID)
					 /* okay */ ;
				else if (procStruct->prorettype == TRIGGEROID)
				{
					free(prodesc->proname);
					free(prodesc);
					ereport(ERROR,
							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
							 errmsg("trigger functions may only be called as triggers")));
				}
				else
				{
					free(prodesc->proname);
					free(prodesc);
					ereport(ERROR,
							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
						 errmsg("plperl functions cannot return type %s",
								format_type_be(procStruct->prorettype))));
				}
			}

			if (typeStruct->typrelid != InvalidOid)
			{
				free(prodesc->proname);
				free(prodesc);
				ereport(ERROR,
						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				   errmsg("plperl functions cannot return tuples yet")));
			}

			perm_fmgr_info(typeStruct->typinput, &(prodesc->result_in_func));
			prodesc->result_in_elem = typeStruct->typelem;

			ReleaseSysCache(typeTup);
		}

		/************************************************************
		 * Get the required information for output conversion
		 * of all procedure arguments
		 ************************************************************/
		if (!is_trigger)
		{
			prodesc->nargs = procStruct->pronargs;
			for (i = 0; i < prodesc->nargs; i++)
			{
				typeTup = SearchSysCache(TYPEOID,
							ObjectIdGetDatum(procStruct->proargtypes[i]),
										 0, 0, 0);
				if (!HeapTupleIsValid(typeTup))
				{
					free(prodesc->proname);
					free(prodesc);
					elog(ERROR, "cache lookup failed for type %u",
						 procStruct->proargtypes[i]);
				}
				typeStruct = (Form_pg_type) GETSTRUCT(typeTup);

				/* Disallow pseudotype argument */
				if (typeStruct->typtype == 'p')
				{
					free(prodesc->proname);
					free(prodesc);
					ereport(ERROR,
							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
						   errmsg("plperl functions cannot take type %s",
						   format_type_be(procStruct->proargtypes[i]))));
				}

				if (typeStruct->typrelid != InvalidOid)
					prodesc->arg_is_rel[i] = 1;
				else
					prodesc->arg_is_rel[i] = 0;

				perm_fmgr_info(typeStruct->typoutput, &(prodesc->arg_out_func[i]));
				prodesc->arg_out_elem[i] = typeStruct->typelem;
				ReleaseSysCache(typeTup);
			}
		}

		/************************************************************
		 * create the text of the anonymous subroutine.
		 * we do not use a named subroutine so that we can call directly
		 * through the reference.
		 *
		 ************************************************************/
		proc_source = DatumGetCString(DirectFunctionCall1(textout,
								  PointerGetDatum(&procStruct->prosrc)));

		/************************************************************
		 * Create the procedure in the interpreter
		 ************************************************************/
		prodesc->reference = plperl_create_sub(proc_source, prodesc->lanpltrusted);
		pfree(proc_source);
		if (!prodesc->reference)
		{
			free(prodesc->proname);
			free(prodesc);
			elog(ERROR, "could not create internal procedure \"%s\"",
				 internal_proname);
		}

		/************************************************************
		 * Add the proc description block to the hashtable
		 ************************************************************/
		hv_store(plperl_proc_hash, internal_proname, proname_len,
				 newSViv((IV) prodesc), 0);
	}

	ReleaseSysCache(procTup);

	return prodesc;
}


/**********************************************************************
 * plperl_build_tuple_argument() - Build a string for a ref to a hash
 *				  from all attributes of a given tuple
 **********************************************************************/
static SV  *
plperl_build_tuple_argument(HeapTuple tuple, TupleDesc tupdesc)
{
	int			i;
	SV		   *output;
	Datum		attr;
	bool		isnull;
	char	   *attname;
	char	   *outputstr;
	HeapTuple	typeTup;
	Oid			typoutput;
	Oid			typelem;

	output = sv_2mortal(newSVpv("{", 0));

	for (i = 0; i < tupdesc->natts; i++)
	{
		/* ignore dropped attributes */
		if (tupdesc->attrs[i]->attisdropped)
			continue;

		/************************************************************
		 * Get the attribute name
		 ************************************************************/
		attname = tupdesc->attrs[i]->attname.data;

		/************************************************************
		 * Get the attributes value
		 ************************************************************/
		attr = heap_getattr(tuple, i + 1, tupdesc, &isnull);

		/************************************************************
		 *	If it is null it will be set to undef in the hash.
		 ************************************************************/
		if (isnull)
		{
			sv_catpvf(output, "'%s' => undef,", attname);
			continue;
		}

		/************************************************************
		 * Lookup the attribute type in the syscache
		 * for the output function
		 ************************************************************/
		typeTup = SearchSysCache(TYPEOID,
						   ObjectIdGetDatum(tupdesc->attrs[i]->atttypid),
								 0, 0, 0);
		if (!HeapTupleIsValid(typeTup))
			elog(ERROR, "cache lookup failed for type %u",
				 tupdesc->attrs[i]->atttypid);

		typoutput = ((Form_pg_type) GETSTRUCT(typeTup))->typoutput;
		typelem = ((Form_pg_type) GETSTRUCT(typeTup))->typelem;
		ReleaseSysCache(typeTup);

		/************************************************************
		 * Append the attribute name and the value to the list.
		 ************************************************************/
		outputstr = DatumGetCString(OidFunctionCall3(typoutput,
													 attr,
											   ObjectIdGetDatum(typelem),
						   Int32GetDatum(tupdesc->attrs[i]->atttypmod)));
		sv_catpvf(output, "'%s' => '%s',", attname, outputstr);
		pfree(outputstr);
	}

	sv_catpv(output, "}");
	output = perl_eval_pv(SvPV(output, PL_na), TRUE);
	return output;
}