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/* valacastexpression.vala
*
* Copyright (C) 2006-2011 Jürg Billeter
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Author:
* Jürg Billeter <j@bitron.ch>
*/
/**
* Represents a type cast in the source code.
*/
public class Vala.CastExpression : Expression {
/**
* The expression to be cast.
*/
public Expression inner {
get {
return _inner;
}
set {
_inner = value;
_inner.parent_node = this;
}
}
/**
* The target type.
*/
public DataType type_reference {
get { return _data_type; }
set {
_data_type = value;
_data_type.parent_node = this;
}
}
/**
* Checked casts return NULL instead of raising an error.
*/
public bool is_silent_cast { get; set; }
public bool is_non_null_cast { get; set; }
private Expression _inner;
private DataType _data_type;
/**
* Creates a new cast expression.
*
* @param inner expression to be cast
* @param type_reference target type
* @return newly created cast expression
*/
public CastExpression (Expression inner, DataType type_reference, SourceReference source_reference, bool is_silent_cast) {
this.type_reference = type_reference;
this.source_reference = source_reference;
this.is_silent_cast = is_silent_cast;
this.inner = inner;
}
public CastExpression.non_null (Expression inner, SourceReference source_reference) {
this.inner = inner;
this.is_non_null_cast = true;
this.source_reference = source_reference;
}
public override void accept (CodeVisitor visitor) {
visitor.visit_cast_expression (this);
visitor.visit_expression (this);
}
public override void accept_children (CodeVisitor visitor) {
inner.accept (visitor);
if (!is_non_null_cast) {
type_reference.accept (visitor);
}
}
public override void replace_expression (Expression old_node, Expression new_node) {
if (inner == old_node) {
inner = new_node;
}
}
public override bool is_pure () {
return inner.is_pure ();
}
public override bool is_accessible (Symbol sym) {
return inner.is_accessible (sym);
}
public override void replace_type (DataType old_type, DataType new_type) {
if (type_reference == old_type) {
type_reference = new_type;
}
}
public override bool check (CodeContext context) {
if (checked) {
return !error;
}
checked = true;
if (!inner.check (context)) {
error = true;
return false;
}
if (inner.value_type == null) {
Report.error (source_reference, "Invalid cast expression");
error = true;
return false;
}
if (is_non_null_cast) {
// (!) non-null cast
type_reference = inner.value_type.copy ();
type_reference.nullable = false;
}
type_reference.check (context);
// FIXME: check whether cast is allowed
if (type_reference is DelegateType && inner.value_type is MethodType) {
if (target_type != null) {
inner.value_type.value_owned = target_type.value_owned;
} else {
inner.value_type.value_owned = true;
}
}
value_type = type_reference;
value_type.value_owned = inner.value_type.value_owned;
if (is_silent_cast) {
value_type.nullable = true;
}
if (is_gvariant (context, inner.value_type) && !is_gvariant (context, value_type)) {
// GVariant unboxing returns owned value
value_type.value_owned = true;
}
inner.target_type = inner.value_type.copy ();
return !error;
}
bool is_gvariant (CodeContext context, DataType type) {
return type.data_type != null && type.data_type.is_subtype_of (context.analyzer.gvariant_type.data_type);
}
public override void emit (CodeGenerator codegen) {
inner.emit (codegen);
codegen.visit_cast_expression (this);
codegen.visit_expression (this);
}
public override void get_defined_variables (Collection<Variable> collection) {
inner.get_defined_variables (collection);
}
public override void get_used_variables (Collection<Variable> collection) {
inner.get_used_variables (collection);
}
public override bool is_constant () {
return inner.is_constant ();
}
}
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