Line data Source code
1 : /* valacastexpression.vala
2 : *
3 : * Copyright (C) 2006-2011 Jürg Billeter
4 : *
5 : * This library is free software; you can redistribute it and/or
6 : * modify it under the terms of the GNU Lesser General Public
7 : * License as published by the Free Software Foundation; either
8 : * version 2.1 of the License, or (at your option) any later version.
9 :
10 : * This library is distributed in the hope that it will be useful,
11 : * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 : * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 : * Lesser General Public License for more details.
14 :
15 : * You should have received a copy of the GNU Lesser General Public
16 : * License along with this library; if not, write to the Free Software
17 : * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18 : *
19 : * Author:
20 : * Jürg Billeter <j@bitron.ch>
21 : */
22 :
23 :
24 : /**
25 : * Represents a type cast in the source code.
26 : */
27 192054 : public class Vala.CastExpression : Expression {
28 : /**
29 : * The expression to be cast.
30 : */
31 : public Expression inner {
32 3199609 : get {
33 3199609 : return _inner;
34 : }
35 190528 : private set {
36 442246 : _inner = value;
37 190528 : _inner.parent_node = this;
38 : }
39 : }
40 :
41 : /**
42 : * The target type.
43 : */
44 : public DataType type_reference {
45 2003341 : get { return _data_type; }
46 251718 : private set {
47 503436 : _data_type = value;
48 251718 : _data_type.parent_node = this;
49 : }
50 : }
51 :
52 : /**
53 : * Checked casts return NULL instead of raising an error.
54 : */
55 179214 : public bool is_silent_cast { get; private set; }
56 :
57 196278 : public bool is_non_null_cast { get; private set; }
58 :
59 190517 : private Expression _inner;
60 :
61 190517 : private DataType _data_type;
62 :
63 : /**
64 : * Creates a new cast expression.
65 : *
66 : * @param inner expression to be cast
67 : * @param type_reference target type
68 : * @return newly created cast expression
69 : */
70 427878 : public CastExpression (Expression inner, DataType type_reference, SourceReference? source_reference = null) {
71 142626 : this.type_reference = type_reference;
72 142626 : this.source_reference = source_reference;
73 142626 : this.is_silent_cast = false;
74 142626 : this.is_non_null_cast = false;
75 142626 : this.inner = inner;
76 : }
77 :
78 1410 : public CastExpression.silent (Expression inner, DataType type_reference, SourceReference? source_reference = null) {
79 470 : this.type_reference = type_reference;
80 470 : this.source_reference = source_reference;
81 470 : this.is_silent_cast = true;
82 470 : this.is_non_null_cast = false;
83 470 : this.inner = inner;
84 : }
85 :
86 142263 : public CastExpression.non_null (Expression inner, SourceReference? source_reference = null) {
87 47421 : this.inner = inner;
88 47421 : this.is_non_null_cast = true;
89 47421 : this.source_reference = source_reference;
90 : }
91 :
92 736210 : public override void accept (CodeVisitor visitor) {
93 736210 : visitor.visit_cast_expression (this);
94 :
95 736210 : visitor.visit_expression (this);
96 : }
97 :
98 736210 : public override void accept_children (CodeVisitor visitor) {
99 736210 : inner.accept (visitor);
100 736210 : if (!is_non_null_cast) {
101 546790 : type_reference.accept (visitor);
102 : }
103 : }
104 :
105 0 : public override string to_string () {
106 0 : if (is_non_null_cast) {
107 0 : return "(!) %s".printf (inner.to_string ());
108 0 : } else if (is_silent_cast) {
109 0 : return "%s as %s".printf (inner.to_string (), type_reference.to_string ());
110 : } else {
111 0 : return "(%s) %s".printf (type_reference.to_string (), inner.to_string ());
112 : }
113 : }
114 :
115 11 : public override void replace_expression (Expression old_node, Expression new_node) {
116 11 : if (inner == old_node) {
117 11 : inner = new_node;
118 : }
119 : }
120 :
121 0 : public override bool is_pure () {
122 0 : return inner.is_pure ();
123 : }
124 :
125 6 : public override bool is_accessible (Symbol sym) {
126 6 : return inner.is_accessible (sym);
127 : }
128 :
129 64735 : public override void replace_type (DataType old_type, DataType new_type) {
130 64735 : if (type_reference == old_type) {
131 64735 : type_reference = new_type;
132 : }
133 : }
134 :
135 3922 : public override bool is_non_null () {
136 3922 : return is_non_null_cast || (!is_silent_cast && inner.is_non_null ());
137 : }
138 :
139 401324 : public override void get_error_types (Collection<DataType> collection, SourceReference? source_reference = null) {
140 401324 : inner.get_error_types (collection, source_reference);
141 : }
142 :
143 227758 : public override bool check (CodeContext context) {
144 227758 : if (checked) {
145 51264 : return !error;
146 : }
147 :
148 176494 : checked = true;
149 :
150 176494 : if (!inner.check (context)) {
151 0 : error = true;
152 0 : return false;
153 : }
154 :
155 176494 : if (inner.value_type == null) {
156 0 : Report.error (source_reference, "Invalid cast expression");
157 0 : error = true;
158 0 : return false;
159 : }
160 :
161 176494 : if (is_non_null_cast) {
162 : // (!) non-null cast
163 43887 : type_reference = inner.value_type.copy ();
164 43887 : type_reference.nullable = false;
165 : }
166 :
167 176494 : type_reference.check (context);
168 :
169 : // FIXME: check whether cast is allowed
170 :
171 176494 : if (type_reference is VoidType) {
172 1 : Report.error (source_reference, "Casting to `void' is not allowed");
173 1 : error = true;
174 1 : return false;
175 : }
176 :
177 : // Allow casting to array or pointer type
178 176493 : if (!(type_reference is ArrayType || type_reference is PointerType)) {
179 106982 : if (!type_reference.is_real_struct_type () && inner.value_type.is_real_struct_type ()
180 55 : && (context.profile != Profile.GOBJECT || !(is_gvariant (context, inner.value_type) || is_gvalue (context, inner.value_type)))) {
181 2 : error = true;
182 2 : Report.error (source_reference, "Casting of struct `%s' to `%s' is not allowed", inner.value_type.to_qualified_string (), type_reference.to_qualified_string ());
183 : }
184 : }
185 :
186 176493 : if (type_reference is DelegateType && inner.value_type is MethodType) {
187 78 : if (target_type != null) {
188 44 : inner.value_type.value_owned = target_type.value_owned;
189 : } else {
190 34 : inner.value_type.value_owned = true;
191 : }
192 : }
193 :
194 : // Implicit transformation of stack-allocated value to heap-allocated boxed-type
195 176532 : if (!(is_silent_cast || is_non_null_cast)
196 132136 : && (type_reference is ValueType && type_reference.nullable)
197 39 : && inner.value_type.is_non_null_simple_type ()) {
198 22 : var local = new LocalVariable (type_reference, get_temp_name (), null, inner.source_reference);
199 22 : var decl = new DeclarationStatement (local, source_reference);
200 :
201 22 : insert_statement (context.analyzer.insert_block, decl);
202 :
203 22 : var temp_access = SemanticAnalyzer.create_temp_access (local, target_type);
204 22 : temp_access.formal_target_type = formal_target_type;
205 :
206 : // don't set initializer earlier as this changes parent_node and parent_statement
207 22 : local.initializer = inner;
208 22 : decl.check (context);
209 :
210 22 : context.analyzer.replaced_nodes.add (this);
211 22 : parent_node.replace_expression (this, temp_access);
212 22 : return temp_access.check (context);
213 : }
214 :
215 176471 : value_type = type_reference;
216 176471 : value_type.value_owned = inner.value_type.value_owned;
217 176471 : value_type.floating_reference = inner.value_type.floating_reference;
218 :
219 176471 : if (is_silent_cast) {
220 470 : value_type.nullable = true;
221 : }
222 :
223 352914 : if (context.profile == Profile.GOBJECT
224 176512 : && is_gvariant (context, inner.value_type) && !is_gvariant (context, value_type)) {
225 : // GVariant unboxing returns owned value
226 68 : value_type.value_owned = true;
227 68 : if (value_type.get_type_signature () == null) {
228 1 : error = true;
229 1 : Report.error (source_reference, "Casting of `GLib.Variant' to `%s' is not supported", value_type.to_qualified_string ());
230 : }
231 : }
232 :
233 352914 : if (context.profile == Profile.GOBJECT
234 176499 : && is_gvalue (context, inner.value_type) && !is_gvalue (context, value_type)) {
235 : // GValue unboxing returns unowned value
236 56 : value_type.value_owned = false;
237 56 : if (value_type.nullable && value_type.type_symbol != null && !value_type.type_symbol.is_reference_type ()) {
238 1 : error = true;
239 1 : Report.error (source_reference, "Casting of `GLib.Value' to `%s' is not supported", value_type.to_qualified_string ());
240 : }
241 : }
242 :
243 176471 : inner.target_type = inner.value_type.copy ();
244 :
245 176471 : return !error;
246 : }
247 :
248 176567 : bool is_gvariant (CodeContext context, DataType type) {
249 176567 : return type.type_symbol != null && type.type_symbol.is_subtype_of (context.analyzer.gvariant_type.type_symbol);
250 : }
251 :
252 176554 : bool is_gvalue (CodeContext context, DataType type) {
253 176554 : return type.type_symbol != null && type.type_symbol.is_subtype_of (context.analyzer.gvalue_type.type_symbol);
254 : }
255 :
256 2918 : public override void emit (CodeGenerator codegen) {
257 2918 : inner.emit (codegen);
258 :
259 2918 : codegen.visit_cast_expression (this);
260 :
261 2918 : codegen.visit_expression (this);
262 : }
263 :
264 362373 : public override void get_defined_variables (Collection<Variable> collection) {
265 362373 : inner.get_defined_variables (collection);
266 : }
267 :
268 120807 : public override void get_used_variables (Collection<Variable> collection) {
269 120807 : inner.get_used_variables (collection);
270 : }
271 :
272 6 : public override bool is_constant () {
273 6 : return inner.is_constant ();
274 : }
275 : }
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