plperl.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

	SPAGAIN;

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

	if (SvTRUE(ERRSV))
	{
		(void) POPs;
		PUTBACK;
		FREETMPS;
		LEAVE;
		/* XXX need to find a way to assign an errcode here */
		ereport(ERROR,
				(errmsg("error from Perl trigger function: %s",
						strip_trailing_ws(SvPV(ERRSV, PL_na)))));
	}

	retval = newSVsv(POPs);

	PUTBACK;
	FREETMPS;
	LEAVE;

	return retval;
}


static Datum
plperl_func_handler(PG_FUNCTION_ARGS)
{
	plperl_proc_desc *prodesc;
	SV		   *perlret;
	Datum		retval;
	ReturnSetInfo *rsi;
	SV		   *array_ret = NULL;

	/*
	 * Create the call_data beforing connecting to SPI, so that it is
	 * not allocated in the SPI memory context
	 */
	current_call_data = (plperl_call_data *) palloc0(sizeof(plperl_call_data));
	current_call_data->fcinfo = fcinfo;

	if (SPI_connect() != SPI_OK_CONNECT)
		elog(ERROR, "could not connect to SPI manager");

	prodesc = compile_plperl_function(fcinfo->flinfo->fn_oid, false);
	current_call_data->prodesc = prodesc;

	rsi = (ReturnSetInfo *) fcinfo->resultinfo;

	if (prodesc->fn_retisset)
	{
		/* Check context before allowing the call to go through */
		if (!rsi || !IsA(rsi, ReturnSetInfo) ||
			(rsi->allowedModes & SFRM_Materialize) == 0 ||
			rsi->expectedDesc == NULL)
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
					 errmsg("set-valued function called in context that "
							"cannot accept a set")));
	}

	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 (prodesc->fn_retisset)
	{
		/*
		 * If the Perl function returned an arrayref, we pretend that it
		 * called return_next() for each element of the array, to handle old
		 * SRFs that didn't know about return_next(). Any other sort of return
		 * value is an error.
		 */
		if (SvTYPE(perlret) == SVt_RV &&
			SvTYPE(SvRV(perlret)) == SVt_PVAV)
		{
			int			i = 0;
			SV		  **svp = 0;
			AV		   *rav = (AV *) SvRV(perlret);

			while ((svp = av_fetch(rav, i, FALSE)) != NULL)
			{
				plperl_return_next(*svp);
				i++;
			}
		}
		else if (SvTYPE(perlret) != SVt_NULL)
		{
			ereport(ERROR,
					(errcode(ERRCODE_DATATYPE_MISMATCH),
					 errmsg("set-returning Perl function must return "
							"reference to array or use return_next")));
		}

		rsi->returnMode = SFRM_Materialize;
		if (current_call_data->tuple_store)
		{
			rsi->setResult = current_call_data->tuple_store;
			rsi->setDesc = current_call_data->ret_tdesc;
		}
		retval = (Datum) 0;
	}
	else if (SvTYPE(perlret) == SVt_NULL)
	{
		/* Return NULL if Perl code returned undef */
		if (rsi && IsA(rsi, ReturnSetInfo))
			rsi->isDone = ExprEndResult;
		fcinfo->isnull = true;
		retval = (Datum) 0;
	}
	else if (prodesc->fn_retistuple)
	{
		/* Return a perl hash converted to a Datum */
		TupleDesc	td;
		AttInMetadata *attinmeta;
		HeapTuple	tup;

		if (!SvOK(perlret) || SvTYPE(perlret) != SVt_RV ||
			SvTYPE(SvRV(perlret)) != SVt_PVHV)
		{
			ereport(ERROR,
					(errcode(ERRCODE_DATATYPE_MISMATCH),
					 errmsg("composite-returning Perl function "
							"must return reference to hash")));
		}

		/* XXX should cache the attinmeta data instead of recomputing */
		if (get_call_result_type(fcinfo, NULL, &td) != TYPEFUNC_COMPOSITE)
		{
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
					 errmsg("function returning record called in context "
							"that cannot accept type record")));
		}

		attinmeta = TupleDescGetAttInMetadata(td);
		tup = plperl_build_tuple_result((HV *) SvRV(perlret), attinmeta);
		retval = HeapTupleGetDatum(tup);
	}
	else
	{
		/* Return a perl string converted to a Datum */
		char	   *val;

		if (prodesc->fn_retisarray && SvROK(perlret) &&
			SvTYPE(SvRV(perlret)) == SVt_PVAV)
		{
			array_ret = plperl_convert_to_pg_array(perlret);
			SvREFCNT_dec(perlret);
			perlret = array_ret;
		}

		val = SvPV(perlret, PL_na);

		retval = FunctionCall3(&prodesc->result_in_func,
							   CStringGetDatum(val),
							   ObjectIdGetDatum(prodesc->result_typioparam),
							   Int32GetDatum(-1));
	}

	if (array_ret == NULL)
		SvREFCNT_dec(perlret);

	current_call_data = NULL;
	return retval;
}


static Datum
plperl_trigger_handler(PG_FUNCTION_ARGS)
{
	plperl_proc_desc *prodesc;
	SV		   *perlret;
	Datum		retval;
	SV		   *svTD;
	HV		   *hvTD;

	/*
	 * Create the call_data beforing connecting to SPI, so that it is
	 * not allocated in the SPI memory context
	 */
	current_call_data = (plperl_call_data *) palloc0(sizeof(plperl_call_data));
	current_call_data->fcinfo = fcinfo;

	/* Connect to SPI manager */
	if (SPI_connect() != SPI_OK_CONNECT)
		elog(ERROR, "could not connect to SPI manager");

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

	svTD = plperl_trigger_build_args(fcinfo);
	perlret = plperl_call_perl_trigger_func(prodesc, fcinfo, svTD);
	hvTD = (HV *) SvRV(svTD);

	/************************************************************
	* 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) && SvTYPE(perlret) != SVt_NULL))
	{
		/* undef result means go ahead with original tuple */
		TriggerData *trigdata = ((TriggerData *) fcinfo->context);

		if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
			retval = (Datum) trigdata->tg_trigtuple;
		else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
			retval = (Datum) trigdata->tg_newtuple;
		else if (TRIGGER_FIRED_BY_DELETE(trigdata->tg_event))
			retval = (Datum) trigdata->tg_trigtuple;
		else
			retval = (Datum) 0; /* can this happen? */
	}
	else
	{
		HeapTuple	trv;
		char	   *tmp;

		tmp = SvPV(perlret, PL_na);

		if (pg_strcasecmp(tmp, "SKIP") == 0)
			trv = NULL;
		else if (pg_strcasecmp(tmp, "MODIFY") == 0)
		{
			TriggerData *trigdata = (TriggerData *) fcinfo->context;

			if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
				trv = plperl_modify_tuple(hvTD, trigdata,
										  trigdata->tg_trigtuple);
			else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
				trv = plperl_modify_tuple(hvTD, trigdata,
										  trigdata->tg_newtuple);
			else
			{
				ereport(WARNING,
						(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
					   errmsg("ignoring modified tuple in DELETE trigger")));
				trv = NULL;
			}
		}
		else
		{
			ereport(ERROR,
					(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
					 errmsg("result of Perl trigger function must be undef, "
							"\"SKIP\" or \"MODIFY\"")));
			trv = NULL;
		}
		retval = PointerGetDatum(trv);
	}

	SvREFCNT_dec(svTD);
	if (perlret)
		SvREFCNT_dec(perlret);

	current_call_data = NULL;
	return retval;
}


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;
	SV		  **svp;

	/* 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
	 ************************************************************/
	svp = hv_fetch(plperl_proc_hash, internal_proname, proname_len, FALSE);
	if (svp)
	{
		bool		uptodate;

		prodesc = (plperl_proc_desc *) SvIV(*svp);

		/************************************************************
		 * 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;
		Datum		prosrcdatum;
		bool		isnull;
		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);

		/* Remember if function is STABLE/IMMUTABLE */
		prodesc->fn_readonly =
			(procStruct->provolatile != PROVOLATILE_VOLATILE);

		/************************************************************
		 * 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 or RECORD */
			if (typeStruct->typtype == 'p')
			{
				if (procStruct->prorettype == VOIDOID ||
					procStruct->prorettype == RECORDOID)
					 /* 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))));
				}
			}

			prodesc->result_oid = procStruct->prorettype;
			prodesc->fn_retisset = procStruct->proretset;
			prodesc->fn_retistuple = (typeStruct->typtype == 'c' ||
									  procStruct->prorettype == RECORDOID);

			prodesc->fn_retisarray =
				(typeStruct->typlen == -1 && typeStruct->typelem);

			perm_fmgr_info(typeStruct->typinput, &(prodesc->result_in_func));
			prodesc->result_typioparam = getTypeIOParam(typeTup);

			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.values[i]),
										 0, 0, 0);
				if (!HeapTupleIsValid(typeTup))
				{
					free(prodesc->proname);
					free(prodesc);
					elog(ERROR, "cache lookup failed for type %u",
						 procStruct->proargtypes.values[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.values[i]))));
				}

				if (typeStruct->typtype == 'c')
					prodesc->arg_is_rowtype[i] = true;
				else
				{