pl_exec.c

关系型数据库 Postgresql 6.5.2

	}

	/* ----------
	 * There are tuples, so set found to true
	 * ----------
	 */
	exec_set_found(estate, true);

	/* ----------
	 * Now do the loop
	 * ----------
	 */
	tuptab = SPI_tuptable;
	SPI_tuptable = NULL;

	for (i = 0; i < n; i++)
	{
		/* ----------
		 * Assign the tuple to the target
		 * ----------
		 */
		exec_move_row(estate, rec, row, tuptab->vals[i], tuptab->tupdesc);

		/* ----------
		 * Execute the statements
		 * ----------
		 */
		rc = exec_stmts(estate, stmt->body);

		/* ----------
		 * Check returncode
		 * ----------
		 */
		switch (rc)
		{
			case PLPGSQL_RC_OK:
				break;

			case PLPGSQL_RC_EXIT:
				if (estate->exitlabel == NULL)
					return PLPGSQL_RC_OK;
				if (stmt->label == NULL)
					return PLPGSQL_RC_EXIT;
				if (strcmp(stmt->label, estate->exitlabel))
					return PLPGSQL_RC_EXIT;
				estate->exitlabel = NULL;
				return PLPGSQL_RC_OK;

			case PLPGSQL_RC_RETURN:
				return PLPGSQL_RC_RETURN;

			default:
				elog(ERROR, "unknown rc %d from exec_stmts()", rc);
		}
	}

	return PLPGSQL_RC_OK;
}


/* ----------
 * exec_stmt_select			Run a query and assign the first
 *					row to a record or rowtype.
 *					 ----------
 */
static int
exec_stmt_select(PLpgSQL_execstate * estate, PLpgSQL_stmt_select * stmt)
{
	PLpgSQL_rec *rec = NULL;
	PLpgSQL_row *row = NULL;
	SPITupleTable *tuptab;
	int			n;

	/* ----------
	 * Initialize the global found variable to false
	 * ----------
	 */
	exec_set_found(estate, false);

	/* ----------
	 * Determine if we assign to a record or a row
	 * ----------
	 */
	if (stmt->rec != NULL)
		rec = (PLpgSQL_rec *) (estate->datums[stmt->rec->recno]);
	else
	{
		if (stmt->row != NULL)
			row = (PLpgSQL_row *) (estate->datums[stmt->row->rowno]);
		else
			elog(ERROR, "unsupported target in exec_stmt_select()");
	}

	/* ----------
	 * Run the query
	 * ----------
	 */
	exec_run_select(estate, stmt->query, 1);
	n = SPI_processed;

	/* ----------
	 * If the query didn't return any row, set the target
	 * to NULL and return.
	 * ----------
	 */
	if (n == 0)
	{
		exec_move_row(estate, rec, row, NULL, NULL);
		return PLPGSQL_RC_OK;
	}

	/* ----------
	 * Put the result into the target and set found to true
	 * ----------
	 */
	tuptab = SPI_tuptable;
	SPI_tuptable = NULL;

	exec_move_row(estate, rec, row, tuptab->vals[0], tuptab->tupdesc);

	exec_set_found(estate, true);

	return PLPGSQL_RC_OK;
}


/* ----------
 * exec_stmt_exit			Start exiting loop(s) or blocks
 * ----------
 */
static int
exec_stmt_exit(PLpgSQL_execstate * estate, PLpgSQL_stmt_exit * stmt)
{
	Datum		value;
	Oid			valtype;
	bool		isnull = false;

	/* ----------
	 * If the exit has a condition, check that it's true
	 * ----------
	 */
	if (stmt->cond != NULL)
	{
		value = exec_eval_expr(estate, stmt->cond, &isnull, &valtype);
		if (!value)
			return PLPGSQL_RC_OK;
	}

	estate->exitlabel = stmt->label;
	return PLPGSQL_RC_EXIT;
}


/* ----------
 * exec_stmt_return			Evaluate an expression and start
 *					returning from the function.
 * ----------
 */
static int
exec_stmt_return(PLpgSQL_execstate * estate, PLpgSQL_stmt_return * stmt)
{
	if (estate->retistuple)
	{
		if (stmt->retrecno >= 0)
		{
			PLpgSQL_rec *rec = (PLpgSQL_rec *) (estate->datums[stmt->retrecno]);

			estate->retval = (Datum) (rec->tup);
			estate->rettupdesc = rec->tupdesc;
			estate->retisnull = !HeapTupleIsValid(rec->tup);

			return PLPGSQL_RC_RETURN;
		}

		if (stmt->expr == NULL)
		{
			estate->retval = (Datum) 0;
			estate->rettupdesc = NULL;
			estate->retisnull = true;
		}
		else
		{
			exec_run_select(estate, stmt->expr, 1);
			estate->retval = (Datum) SPI_copytuple(SPI_tuptable->vals[0]);
			estate->rettupdesc = SPI_tuptable->tupdesc;
			estate->retisnull = false;
		}
		return PLPGSQL_RC_RETURN;
	}

	estate->retval = exec_eval_expr(estate, stmt->expr,
									&(estate->retisnull),
									&(estate->rettype));

	return PLPGSQL_RC_RETURN;
}


/* ----------
 * exec_stmt_raise			Build a message and throw it with
 *					elog()
 * ----------
 */
static int
exec_stmt_raise(PLpgSQL_execstate * estate, PLpgSQL_stmt_raise * stmt)
{
	HeapTuple	typetup;
	Form_pg_type typeStruct;
	FmgrInfo	finfo_output;
	char	   *extval;
	int			pidx = 0;
	char		c[2] = {0, 0};
	char	   *cp;
	PLpgSQL_dstring ds;
	PLpgSQL_var *var;
	PLpgSQL_rec *rec;
	PLpgSQL_recfield *recfield;
	int			fno;

	plpgsql_dstring_init(&ds);

	for (cp = stmt->message; *cp; cp++)
	{
		/* ----------
		 * Occurences of a single % are replaced by the next
		 * arguments external representation. Double %'s are
		 * left as is so elog() will also don't touch them.
		 * ----------
		 */
		if ((c[0] = *cp) == '%')
		{
			cp++;
			if (*cp == '%')
			{
				plpgsql_dstring_append(&ds, c);
				plpgsql_dstring_append(&ds, c);
				continue;
			}
			cp--;
			if (pidx >= stmt->nparams)
			{
				plpgsql_dstring_append(&ds, c);
				plpgsql_dstring_append(&ds, c);
				continue;
			}
			switch (estate->datums[stmt->params[pidx]]->dtype)
			{
				case PLPGSQL_DTYPE_VAR:
					var = (PLpgSQL_var *)
						(estate->datums[stmt->params[pidx]]);
					if (var->isnull)
						extval = "<NULL>";
					else
					{
						typetup = SearchSysCacheTuple(TYPOID,
						ObjectIdGetDatum(var->datatype->typoid), 0, 0, 0);
						if (!HeapTupleIsValid(typetup))
							elog(ERROR, "cache lookup for type %u failed (1)", var->datatype->typoid);
						typeStruct = (Form_pg_type) GETSTRUCT(typetup);

						fmgr_info(typeStruct->typoutput, &finfo_output);
						extval = (char *) (*fmgr_faddr(&finfo_output)) (var->value, &(var->isnull), var->datatype->atttypmod);
					}
					plpgsql_dstring_append(&ds, extval);
					break;

				case PLPGSQL_DTYPE_RECFIELD:
					recfield = (PLpgSQL_recfield *)
						(estate->datums[stmt->params[pidx]]);
					rec = (PLpgSQL_rec *)
						(estate->datums[recfield->recno]);
					if (!HeapTupleIsValid(rec->tup))
						extval = "<NULL>";
					else
					{
						fno = SPI_fnumber(rec->tupdesc, recfield->fieldname);
						if (fno == SPI_ERROR_NOATTRIBUTE)
							elog(ERROR, "record %s has no field %s", rec->refname, recfield->fieldname);
						extval = SPI_getvalue(rec->tup, rec->tupdesc, fno);
					}
					plpgsql_dstring_append(&ds, extval);
					break;

				case PLPGSQL_DTYPE_TRIGARG:
					{
						PLpgSQL_trigarg *trigarg;
						int			value;
						Oid			valtype;
						bool		valisnull = false;

						trigarg = (PLpgSQL_trigarg *)
							(estate->datums[stmt->params[pidx]]);
						value = (int) exec_eval_expr(estate, trigarg->argnum,
												   &valisnull, &valtype);
						if (valisnull)
							extval = "<INDEX_IS_NULL>";
						else
						{
							if (value < 0 || value >= estate->trig_nargs)
								extval = "<OUT_OF_RANGE>";
							else
								extval = textout((text *) (estate->trig_argv[value]));
						}
						plpgsql_dstring_append(&ds, extval);
					}
					break;

				default:
					c[0] = '?';
					plpgsql_dstring_append(&ds, c);
					break;
			}
			pidx++;
			continue;
		}

		/* ----------
		 * Occurences of single ' are removed. double ' are reduced
		 * to single ones.
		 * ----------
		 */
		if (*cp == '\'')
		{
			cp++;
			if (*cp == '\'')
				plpgsql_dstring_append(&ds, c);
			else
				cp--;
			continue;
		}
		plpgsql_dstring_append(&ds, c);
	}

	/* ----------
	 * Now suppress debug info and throw the elog()
	 * ----------
	 */
	if (stmt->elog_level == ERROR)
	{
		error_info_func = NULL;
		error_info_stmt = NULL;
		error_info_text = NULL;
	}
	elog(stmt->elog_level, "%s", plpgsql_dstring_get(&ds));
	plpgsql_dstring_free(&ds);

	return PLPGSQL_RC_OK;
}


/* ----------
 * Generate a prepared plan
 * ----------
 */
static void
exec_prepare_plan(PLpgSQL_execstate * estate,
				  PLpgSQL_expr * expr)
{
	PLpgSQL_var *var;
	PLpgSQL_rec *rec;
	PLpgSQL_recfield *recfield;
	int			i;
	int			fno;
	void	   *plan;
	Oid		   *argtypes;

	/* ----------
	 * Setup the argtypes array
	 * ----------
	 */
	argtypes = malloc(sizeof(Oid *) * (expr->nparams + 1));

	for (i = 0; i < expr->nparams; i++)
	{
		switch (estate->datums[expr->params[i]]->dtype)
		{
			case PLPGSQL_DTYPE_VAR:
				var = (PLpgSQL_var *) (estate->datums[expr->params[i]]);
				argtypes[i] = var->datatype->typoid;
				break;

			case PLPGSQL_DTYPE_RECFIELD:
				recfield = (PLpgSQL_recfield *) (estate->datums[expr->params[i]]);
				rec = (PLpgSQL_rec *) (estate->datums[recfield->recno]);

				if (!HeapTupleIsValid(rec->tup))
					elog(ERROR, "record %s is unassigned yet", rec->refname);
				fno = SPI_fnumber(rec->tupdesc, recfield->fieldname);
				if (fno == SPI_ERROR_NOATTRIBUTE)
					elog(ERROR, "record %s has no field %s", rec->refname, recfield->fieldname);
				argtypes[i] = SPI_gettypeid(rec->tupdesc, fno);
				break;

			case PLPGSQL_DTYPE_TRIGARG:
				argtypes[i] = (Oid) TEXTOID;
				break;

			default:
				elog(ERROR, "unknown parameter dtype %d in exec_run_select()", estate->datums[expr->params[i]]);
		}
	}

	/* ----------
	 * Generate and save the plan
	 * ----------
	 */
	plan = SPI_prepare(expr->query, expr->nparams, argtypes);
	if (plan == NULL)
		elog(ERROR, "SPI_prepare() failed on \"%s\"", expr->query);
	expr->plan = SPI_saveplan(plan);
	expr->plan_argtypes = argtypes;
	expr->plan_simple_expr = NULL;
	exec_simple_check_plan(expr);
}


/* ----------
 * exec_stmt_execsql			Execute an SQL statement not
 *					returning any data.
 * ----------
 */
static int
exec_stmt_execsql(PLpgSQL_execstate * estate,
				  PLpgSQL_stmt_execsql * stmt)
{
	PLpgSQL_var *var;
	PLpgSQL_rec *rec;
	PLpgSQL_recfield *recfield;
	PLpgSQL_trigarg *trigarg;
	int			tgargno;
	Oid			tgargoid;
	int			fno;
	int			i;
	Datum	   *values;
	char	   *nulls;
	int			rc;
	PLpgSQL_expr *expr = stmt->sqlstmt;
	bool		isnull;

	/* ----------
	 * On the first call for this expression generate the plan
	 * ----------
	 */
	if (expr->plan == NULL)
		exec_prepare_plan(estate, expr);

	/* ----------
	 * Now build up the values and nulls arguments for SPI_execp()
	 * ----------
	 */
	values = palloc(sizeof(Datum) * (expr->nparams + 1));
	nulls = palloc(expr->nparams + 1);

	for (i = 0; i < expr->nparams; i++)
	{
		switch (estate->datums[expr->params[i]]->dtype)
		{
			case PLPGSQL_DTYPE_VAR:
				var = (PLpgSQL_var *) (estate->datums[expr->params[i]]);
				values[i] = var->value;
				if (var->isnull)
					nulls[i] = 'n';
				else
					nulls[i] = ' ';
				break;

			case PLPGSQL_DTYPE_RECFIELD:
				recfield = (PLpgSQL_recfield *) (estate->datums[expr->params[i]]);
				rec = (PLpgSQL_rec *) (estate->datums[recfield->recno]);

				if (!HeapTupleIsValid(rec->tup))
					elog(ERROR, "record %s is unassigned yet", rec->refname);
				fno = SPI_fnumber(rec->tupdesc, recfield->fieldname);
				if (fno == SPI_ERROR_NOATTRIBUTE)
					elog(ERROR, "record %s has no field %s", rec->refname, recfield->fieldname);

				if (expr->plan_argtypes[i] != SPI_gettypeid(rec->tupdesc, fno))
					elog(ERROR, "type of %s.%s doesn't match that when preparing the plan", rec->refname, recfield->fieldname);

				values[i] = SPI_getbinval(rec->tup, rec->tupdesc, fno, &isnull);
				if (isnull)
					nulls[i] = 'n';
				else
					nulls[i] = ' ';
				break;

			case PLPGSQL_DTYPE_TRIGARG:
				trigarg = (PLpgSQL_trigarg *) (estate->datums[expr->params[i]]);
				tgargno = (int) exec_eval_expr(estate, trigarg->argnum,
											   &isnull, &tgargoid);
				if (isnull || tgargno < 0 || tgargno >= estate->trig_nargs)
				{
					values[i] = 0;
					nulls[i] = 'n';
				}
				else
				{
					values[i] = estate->trig_argv[tgargno];
					nulls[i] = ' ';
				}
				break;

			default:
				elog(ERROR, "unknown parameter dtype %d in exec_stmt_execsql()", estate->datums[expr->params[i]]->dtype);
		}
	}
	nulls[i] = '\0';

	/* ----------
	 * Execute the plan
	 * ----------
	 */
	rc = SPI_execp(expr->plan, values, nulls, 0);
	switch (rc)
	{
		case SPI_OK_UTILITY:
		case SPI_OK_SELINTO:
		case SPI_OK_INSERT:
		case SPI_OK_DELETE:
		case SPI_OK_UPDATE:
			break;

		case SPI_OK_SELECT:
			elog(ERROR, "unexpected SELECT query in exec_stmt_execsql()");

		default:
			elog(ERROR, "error executing query \"%s\"",
				 expr->query);
	}
	pfree(values);
	pfree(nulls);

	return PLPGSQL_RC_OK;
}


/* ----------
 * exec_assign_expr			Put an expressions result into
 *					a variable.
 * ----------
 */
static void
exec_assign_expr(PLpgSQL_execstate * estate, PLpgSQL_datum * target,
				 PLpgSQL_expr * expr)
{
	Datum		value;
	Oid			valtype;
	bool		isnull = false;

	value = exec_eval_expr(estate, expr, &isnull, &valtype);
	if (target != NULL)
		exec_assign_value(estate, target, value, valtype, &isnull);
}


/* ----------
 * exec_assign_value			Put a value into a target field
 * ----------
 */
static void
exec_assign_value(PLpgSQL_execstate * estate,
				  PLpgSQL_datum * target,
				  Datum value, Oid valtype, bool *isNull)
{
	PLpgSQL_var *var;
	PLpgSQL_rec *rec;
	PLpgSQL_recfield *recfield;
	int			fno;
	int			i;
	int			natts;
	Datum	   *values;
	char	   *nulls;
	bool		attisnull;
	Oid			atttype;
	int4		atttypmod;
	HeapTuple	typetup;
	Form_pg_type typeStruct;
	FmgrInfo	finfo_input;

	switch (target->dtype)
	{
		case PLPGSQL_DTYPE_VAR:
			/* ----------
			 * Target field is a variable - that's easy
			 * ----------
			 */
			var = (PLpgSQL_var *) target;
			var->value = exec_cast_value(value, valtype, var->datatype->typoid,
										 &(var->datatype->typinput),
									   var->datatype->atttypmod, isNull);

			if (isNull && var->notnull)
				elog(ERROR, "NULL assignment to variable '%s' declared NOT NULL", var->refname);

			var->isnull = *isNull;
			break;

		case PLPGSQL_DTYPE_RECFIELD:
			/* ----------
			 * Target field is a record
			 * ----------
			 */
			recfield = (PLpgSQL_recfield *) target;
			rec = (PLpgSQL_rec *) (estate->datums[recfield->recno]);

			/* ----------
			 * Check that there is already a tuple in the record.
			 * We need that because records don't have any predefined
			 * field structure.
			 * ----------
			 */
			if (!HeapTupleIsValid(rec->tup))
				elog(ERROR, "record %s is unassigned yet - don't know it's tuple structure", rec->refname);

			/* ----------
			 * Get the number of the records field to change and the
			 * number of attributes in the tuple.
			 * ----------
			 */
			fno = SPI_fnumber(rec->tupdesc, recfield->fieldname);
			if (fno == SPI_ERROR_NOATTRIBUTE)
				elog(ERROR, "record %s has no field %s", rec->refname, recfield->fieldname);
			fno--;
			natts = rec->tupdesc->natts;

			/* ----------
			 * We loop over the attributes of the rec's current tuple
			 * and collect the values in a Datum array along with the
			 * nulls information.
			 * ----------
			 */
			values = palloc(sizeof(Datum) * natts);
			nulls = palloc(natts + 1);

			for (i = 0; i < natts; i++)
			{
				/* ----------
				 * If this isn't the field we assign to, just use the
				 * value that's already in the tuple.
				 * ----------
				 */
				if (i != fno)
				{
					values[i] = SPI_getbinval(rec->tup, rec->tupdesc,
											  i + 1, &attisnull);
					if (attisnull)
						nulls[i] = 'n';
					else
						nulls[i] = ' ';
					continue;
				}