pl_exec.c

PostgreSQL7.4.6 for Linux

	 */

	var = (PLpgSQL_var *) (estate.datums[func->tg_op_varno]);
	var->isnull = false;
	var->freeval = false;

	if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
		var->value = DirectFunctionCall1(textin, CStringGetDatum("INSERT"));
	else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
		var->value = DirectFunctionCall1(textin, CStringGetDatum("UPDATE"));
	else if (TRIGGER_FIRED_BY_DELETE(trigdata->tg_event))
		var->value = DirectFunctionCall1(textin, CStringGetDatum("DELETE"));
	else
		elog(ERROR, "unrecognized trigger action: not INSERT, DELETE, or UPDATE");

	var = (PLpgSQL_var *) (estate.datums[func->tg_name_varno]);
	var->isnull = false;
	var->freeval = true;
	var->value = DirectFunctionCall1(namein,
						  CStringGetDatum(trigdata->tg_trigger->tgname));

	var = (PLpgSQL_var *) (estate.datums[func->tg_when_varno]);
	var->isnull = false;
	var->freeval = true;
	if (TRIGGER_FIRED_BEFORE(trigdata->tg_event))
		var->value = DirectFunctionCall1(textin, CStringGetDatum("BEFORE"));
	else if (TRIGGER_FIRED_AFTER(trigdata->tg_event))
		var->value = DirectFunctionCall1(textin, CStringGetDatum("AFTER"));
	else
		elog(ERROR, "unrecognized trigger execution time: not BEFORE or AFTER");

	var = (PLpgSQL_var *) (estate.datums[func->tg_level_varno]);
	var->isnull = false;
	var->freeval = true;
	if (TRIGGER_FIRED_FOR_ROW(trigdata->tg_event))
		var->value = DirectFunctionCall1(textin, CStringGetDatum("ROW"));
	else if (TRIGGER_FIRED_FOR_STATEMENT(trigdata->tg_event))
		var->value = DirectFunctionCall1(textin, CStringGetDatum("STATEMENT"));
	else
		elog(ERROR, "unrecognized trigger event type: not ROW or STATEMENT");

	var = (PLpgSQL_var *) (estate.datums[func->tg_relid_varno]);
	var->isnull = false;
	var->freeval = false;
	var->value = ObjectIdGetDatum(trigdata->tg_relation->rd_id);

	var = (PLpgSQL_var *) (estate.datums[func->tg_relname_varno]);
	var->isnull = false;
	var->freeval = true;
	var->value = DirectFunctionCall1(namein,
		CStringGetDatum(RelationGetRelationName(trigdata->tg_relation)));

	var = (PLpgSQL_var *) (estate.datums[func->tg_nargs_varno]);
	var->isnull = false;
	var->freeval = false;
	var->value = Int16GetDatum(trigdata->tg_trigger->tgnargs);

	/*
	 * Store the actual call argument values into the special execution
	 * state variables
	 */
	estate.err_text = gettext_noop("while storing call arguments into local variables");
	estate.trig_nargs = trigdata->tg_trigger->tgnargs;
	if (estate.trig_nargs == 0)
		estate.trig_argv = NULL;
	else
	{
		estate.trig_argv = palloc(sizeof(Datum) * estate.trig_nargs);
		for (i = 0; i < trigdata->tg_trigger->tgnargs; i++)
			estate.trig_argv[i] = DirectFunctionCall1(textin,
					   CStringGetDatum(trigdata->tg_trigger->tgargs[i]));
	}

	/*
	 * Initialize the other variables to NULL values for now. The default
	 * values are set when the blocks are entered.
	 */
	estate.err_text = gettext_noop("while initializing local variables to NULL");
	for (i = estate.found_varno; i < estate.ndatums; i++)
	{
		switch (estate.datums[i]->dtype)
		{
			case PLPGSQL_DTYPE_VAR:
				{
					PLpgSQL_var *var = (PLpgSQL_var *) estate.datums[i];

					var->value = 0;
					var->isnull = true;
					var->freeval = false;
				}
				break;

			case PLPGSQL_DTYPE_ROW:
			case PLPGSQL_DTYPE_REC:
			case PLPGSQL_DTYPE_RECFIELD:
			case PLPGSQL_DTYPE_ARRAYELEM:
			case PLPGSQL_DTYPE_TRIGARG:
				break;

			default:
				elog(ERROR, "unrecognized dtype: %d", func->datums[i]->dtype);
		}
	}

	/*
	 * Set the magic variable FOUND to false
	 */
	exec_set_found(&estate, false);

	/*
	 * Now call the toplevel block of statements
	 */
	estate.err_text = NULL;
	estate.err_stmt = (PLpgSQL_stmt *) (func->action);
	if (exec_stmt_block(&estate, func->action) != PLPGSQL_RC_RETURN)
	{
		estate.err_stmt = NULL;
		estate.err_text = NULL;
		ereport(ERROR,
		   (errcode(ERRCODE_S_R_E_FUNCTION_EXECUTED_NO_RETURN_STATEMENT),
			errmsg("control reached end of trigger procedure without RETURN")));
	}

	if (estate.retisset)
		ereport(ERROR,
				(errcode(ERRCODE_DATATYPE_MISMATCH),
				 errmsg("trigger procedure cannot return a set")));

	/*
	 * Check that the returned tuple structure has the same attributes,
	 * the relation that fired the trigger has. A per-statement trigger
	 * always needs to return NULL, so we ignore any return value the
	 * function itself produces (XXX: is this a good idea?)
	 *
	 * XXX This way it is possible, that the trigger returns a tuple where
	 * attributes don't have the correct atttypmod's length. It's up to
	 * the trigger's programmer to ensure that this doesn't happen. Jan
	 */
	if (estate.retisnull || TRIGGER_FIRED_FOR_STATEMENT(trigdata->tg_event))
		rettup = NULL;
	else
	{
		if (!compatible_tupdesc(estate.rettupdesc,
								trigdata->tg_relation->rd_att))
			ereport(ERROR,
					(errcode(ERRCODE_DATATYPE_MISMATCH),
					 errmsg("returned tuple structure does not match table of trigger event")));
		/* Copy tuple to upper executor memory */
		rettup = SPI_copytuple((HeapTuple) (estate.retval));
	}

	/* Clean up any leftover temporary memory */
	if (estate.eval_econtext != NULL)
		FreeExprContext(estate.eval_econtext);
	estate.eval_econtext = NULL;
	exec_eval_cleanup(&estate);

	/*
	 * Pop the error context stack
	 */
	error_context_stack = plerrcontext.previous;

	/*
	 * Return the triggers result
	 */
	return rettup;
}


/*
 * error context callback to let us supply a call-stack traceback
 */
static void
plpgsql_exec_error_callback(void *arg)
{
	PLpgSQL_execstate *estate = (PLpgSQL_execstate *) arg;

	/* safety check, shouldn't happen */
	if (estate->err_func == NULL)
		return;

	/* if we are doing RAISE, don't report its location */
	if (estate->err_text == raise_skip_msg)
		return;

	if (estate->err_stmt != NULL)
	{
		/* translator: last %s is a plpgsql statement type name */
		errcontext("PL/pgSQL function \"%s\" line %d at %s",
				   estate->err_func->fn_name,
				   estate->err_stmt->lineno,
				   plpgsql_stmt_typename(estate->err_stmt));
	}
	else if (estate->err_text != NULL)
	{
		/*
		 * We don't expend the cycles to run gettext() on err_text unless
		 * we actually need it.  Therefore, places that set up err_text
		 * should use gettext_noop() to ensure the strings get recorded in
		 * the message dictionary.
		 */

		/*
		 * translator: last %s is a phrase such as "while storing call
		 * arguments into local variables"
		 */
		errcontext("PL/pgSQL function \"%s\" %s",
				   estate->err_func->fn_name,
				   gettext(estate->err_text));
	}
	else
		errcontext("PL/pgSQL function \"%s\"",
				   estate->err_func->fn_name);
}


/* ----------
 * Support functions for copying local execution variables
 * ----------
 */
static PLpgSQL_var *
copy_var(PLpgSQL_var * var)
{
	PLpgSQL_var *new = palloc(sizeof(PLpgSQL_var));

	memcpy(new, var, sizeof(PLpgSQL_var));
	new->freeval = false;

	return new;
}


static PLpgSQL_rec *
copy_rec(PLpgSQL_rec * rec)
{
	PLpgSQL_rec *new = palloc(sizeof(PLpgSQL_rec));

	memcpy(new, rec, sizeof(PLpgSQL_rec));
	new->tup = NULL;
	new->tupdesc = NULL;
	new->freetup = false;
	new->freetupdesc = false;

	return new;
}


/* ----------
 * exec_stmt_block			Execute a block of statements
 * ----------
 */
static int
exec_stmt_block(PLpgSQL_execstate * estate, PLpgSQL_stmt_block * block)
{
	int			rc;
	int			i;
	int			n;

	/*
	 * First initialize all variables declared in this block
	 */
	for (i = 0; i < block->n_initvars; i++)
	{
		n = block->initvarnos[i];

		switch (estate->datums[n]->dtype)
		{
			case PLPGSQL_DTYPE_VAR:
				{
					PLpgSQL_var *var = (PLpgSQL_var *) (estate->datums[n]);

					if (var->freeval)
					{
						pfree((void *) (var->value));
						var->freeval = false;
					}

					if (!var->isconst || var->isnull)
					{
						if (var->default_val == NULL)
						{
							var->value = (Datum) 0;
							var->isnull = true;
							if (var->notnull)
								ereport(ERROR,
								(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
								 errmsg("variable \"%s\" declared NOT NULL cannot default to NULL",
										var->refname)));
						}
						else
						{
							exec_assign_expr(estate, (PLpgSQL_datum *) var,
											 var->default_val);
						}
					}
				}
				break;

			case PLPGSQL_DTYPE_REC:
				{
					PLpgSQL_rec *rec = (PLpgSQL_rec *) (estate->datums[n]);

					if (rec->freetup)
					{
						heap_freetuple(rec->tup);
						FreeTupleDesc(rec->tupdesc);
						rec->freetup = false;
					}

					rec->tup = NULL;
					rec->tupdesc = NULL;
				}
				break;

			case PLPGSQL_DTYPE_RECFIELD:
			case PLPGSQL_DTYPE_ARRAYELEM:
				break;

			default:
				elog(ERROR, "unrecognized dtype: %d",
					 estate->datums[n]->dtype);
		}

	}

	/*
	 * Execute the statements in the block's body
	 */
	rc = exec_stmts(estate, block->body);

	/*
	 * Handle the return code.
	 */
	switch (rc)
	{
		case PLPGSQL_RC_OK:
			return PLPGSQL_RC_OK;

		case PLPGSQL_RC_EXIT:
			if (estate->exitlabel == NULL)
				return PLPGSQL_RC_OK;
			if (block->label == NULL)
				return PLPGSQL_RC_EXIT;
			if (strcmp(block->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, "unrecognized rc: %d", rc);
	}

	return PLPGSQL_RC_OK;
}


/* ----------
 * exec_stmts			Iterate over a list of statements
 *				as long as their return code is OK
 * ----------
 */
static int
exec_stmts(PLpgSQL_execstate * estate, PLpgSQL_stmts * stmts)
{
	int			rc;
	int			i;

	for (i = 0; i < stmts->stmts_used; i++)
	{
		rc = exec_stmt(estate, (PLpgSQL_stmt *) (stmts->stmts[i]));
		if (rc != PLPGSQL_RC_OK)
			return rc;
	}

	return PLPGSQL_RC_OK;
}


/* ----------
 * exec_stmt			Distribute one statement to the statements
 *				type specific execution function.
 * ----------
 */
static int
exec_stmt(PLpgSQL_execstate * estate, PLpgSQL_stmt * stmt)
{
	PLpgSQL_stmt *save_estmt;
	int			rc = -1;

	save_estmt = estate->err_stmt;
	estate->err_stmt = stmt;

	CHECK_FOR_INTERRUPTS();

	switch (stmt->cmd_type)
	{
		case PLPGSQL_STMT_BLOCK:
			rc = exec_stmt_block(estate, (PLpgSQL_stmt_block *) stmt);
			break;

		case PLPGSQL_STMT_ASSIGN:
			rc = exec_stmt_assign(estate, (PLpgSQL_stmt_assign *) stmt);
			break;

		case PLPGSQL_STMT_PERFORM:
			rc = exec_stmt_perform(estate, (PLpgSQL_stmt_perform *) stmt);
			break;

		case PLPGSQL_STMT_GETDIAG:
			rc = exec_stmt_getdiag(estate, (PLpgSQL_stmt_getdiag *) stmt);
			break;

		case PLPGSQL_STMT_IF:
			rc = exec_stmt_if(estate, (PLpgSQL_stmt_if *) stmt);
			break;

		case PLPGSQL_STMT_LOOP:
			rc = exec_stmt_loop(estate, (PLpgSQL_stmt_loop *) stmt);
			break;

		case PLPGSQL_STMT_WHILE:
			rc = exec_stmt_while(estate, (PLpgSQL_stmt_while *) stmt);
			break;

		case PLPGSQL_STMT_FORI:
			rc = exec_stmt_fori(estate, (PLpgSQL_stmt_fori *) stmt);
			break;

		case PLPGSQL_STMT_FORS:
			rc = exec_stmt_fors(estate, (PLpgSQL_stmt_fors *) stmt);
			break;

		case PLPGSQL_STMT_SELECT:
			rc = exec_stmt_select(estate, (PLpgSQL_stmt_select *) stmt);
			break;

		case PLPGSQL_STMT_EXIT:
			rc = exec_stmt_exit(estate, (PLpgSQL_stmt_exit *) stmt);
			break;

		case PLPGSQL_STMT_RETURN:
			rc = exec_stmt_return(estate, (PLpgSQL_stmt_return *) stmt);
			break;

		case PLPGSQL_STMT_RETURN_NEXT:
			rc = exec_stmt_return_next(estate, (PLpgSQL_stmt_return_next *) stmt);
			break;

		case PLPGSQL_STMT_RAISE:
			rc = exec_stmt_raise(estate, (PLpgSQL_stmt_raise *) stmt);
			break;

		case PLPGSQL_STMT_EXECSQL:
			rc = exec_stmt_execsql(estate, (PLpgSQL_stmt_execsql *) stmt);
			break;

		case PLPGSQL_STMT_DYNEXECUTE:
			rc = exec_stmt_dynexecute(estate, (PLpgSQL_stmt_dynexecute *) stmt);
			break;

		case PLPGSQL_STMT_DYNFORS:
			rc = exec_stmt_dynfors(estate, (PLpgSQL_stmt_dynfors *) stmt);
			break;

		case PLPGSQL_STMT_OPEN:
			rc = exec_stmt_open(estate, (PLpgSQL_stmt_open *) stmt);
			break;

		case PLPGSQL_STMT_FETCH:
			rc = exec_stmt_fetch(estate, (PLpgSQL_stmt_fetch *) stmt);
			break;

		case PLPGSQL_STMT_CLOSE:
			rc = exec_stmt_close(estate, (PLpgSQL_stmt_close *) stmt);
			break;

		default:
			estate->err_stmt = save_estmt;
			elog(ERROR, "unrecognized cmdtype: %d", stmt->cmd_type);
	}

	estate->err_stmt = save_estmt;

	return rc;
}


/* ----------
 * exec_stmt_assign			Evaluate an expression and
 *					put the result into a variable.
 * ----------
 */
static int
exec_stmt_assign(PLpgSQL_execstate * estate, PLpgSQL_stmt_assign * stmt)
{
	Assert(stmt->varno >= 0);

	exec_assign_expr(estate, estate->datums[stmt->varno], stmt->expr);

	return PLPGSQL_RC_OK;
}

/* ----------
 * exec_stmt_perform		Evaluate query and discard result (but set
 *							FOUND depending on whether at least one row
 *							was returned).
 * ----------
 */
static int
exec_stmt_perform(PLpgSQL_execstate * estate, PLpgSQL_stmt_perform * stmt)
{
	PLpgSQL_expr *expr = stmt->expr;
	int			rc;

	/*
	 * If not already done create a plan for this expression
	 */
	if (expr->plan == NULL)
		exec_prepare_plan(estate, expr);

	rc = exec_run_select(estate, expr, 0, NULL);
	if (rc != SPI_OK_SELECT)
		ereport(ERROR,
				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
			   errmsg("query \"%s\" did not return data", expr->query)));

	exec_set_found(estate, (estate->eval_processed != 0));