vala/valadatatype.vala

   1 /* valadatatype.vala
   2  *
   3  * Copyright (C) 2006-2010  Jürg Billeter
   4  * Copyright (C) 2006-2008  Raffaele Sandrini
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
  19  *
  20  * Author:
  21  *      Jürg Billeter <j@bitron.ch>
  22  *      Raffaele Sandrini <raffaele@sandrini.ch>
  23  */
  24
  25 using GLib;
  26
  27 /**
  28  * A reference to a data type. This is used to specify static types of
  29  * expressions.
  30  */
  31 public abstract class Vala.DataType : CodeNode {
  32         /**
  33          * Specifies that the expression or variable owns the value.
  34          */
  35         public bool value_owned { get; set; }
  36
  37         /**
  38          * Specifies that the expression may be null.
  39          */
  40         public bool nullable { get; set; }
  41
  42         /**
  43          * The referred data type.
  44          */
  45         public weak TypeSymbol data_type { get; set; }
  46
  47         /**
  48          * Specifies that the expression transfers a floating reference.
  49          */
  50         public bool floating_reference { get; set; }
  51
  52         /**
  53          * Specifies that the type supports dynamic lookup.
  54          */
  55         public bool is_dynamic { get; set; }
  56
  57         private List<DataType> type_argument_list;
  58         private static List<DataType> _empty_type_list;
  59
  60         /**
  61          * Appends the specified type as generic type argument.
  62          *
  63          * @param arg a type reference
  64          */
  65         public void add_type_argument (DataType arg) {
  66                 if (type_argument_list == null) {
  67                         type_argument_list = new ArrayList<DataType> ();
  68                 }
  69                 type_argument_list.add (arg);
  70                 arg.parent_node = this;
  71         }
  72
  73         /**
  74          * Returns a copy of the list of generic type arguments.
  75          *
  76          * @return type argument list
  77          */
  78         public List<DataType> get_type_arguments () {
  79                 if (type_argument_list != null) {
  80                         return type_argument_list;
  81                 }
  82                 if (_empty_type_list == null) {
  83                         _empty_type_list = new ArrayList<DataType> ();
  84                 }
  85                 return _empty_type_list;
  86         }
  87
  88         public bool has_type_arguments () {
  89                 if (type_argument_list == null) {
  90                         return false;
  91                 }
  92
  93                 return type_argument_list.size > 0;
  94         }
  95
  96         /**
  97          * Removes all generic type arguments.
  98          */
  99         public void remove_all_type_arguments () {
 100                 type_argument_list = null;
 101         }
 102
 103         public override void accept (CodeVisitor visitor) {
 104                 visitor.visit_data_type (this);
 105         }
 106
 107         public override void accept_children (CodeVisitor visitor) {
 108                 if (type_argument_list != null && type_argument_list.size > 0) {
 109                         foreach (DataType type_arg in type_argument_list) {
 110                                 type_arg.accept (visitor);
 111                         }
 112                 }
 113         }
 114
 115         public override string to_string () {
 116                 return to_qualified_string (null);
 117         }
 118
 119         public virtual string to_qualified_string (Scope? scope = null) {
 120                 // logic temporarily duplicated in DelegateType class
 121
 122                 string s;
 123
 124                 if (data_type != null) {
 125                         Symbol global_symbol = data_type;
 126                         while (global_symbol.parent_symbol.name != null) {
 127                                 global_symbol = global_symbol.parent_symbol;
 128                         }
 129
 130                         Symbol sym = null;
 131                         Scope parent_scope = scope;
 132                         while (sym == null && parent_scope != null) {
 133                                 sym = parent_scope.lookup (global_symbol.name);
 134                                 parent_scope = parent_scope.parent_scope;
 135                         }
 136
 137                         if (sym != null && global_symbol != sym) {
 138                                 s = "global::" + data_type.get_full_name ();;
 139                         } else {
 140                                 s = data_type.get_full_name ();
 141                         }
 142                 } else {
 143                         s = "null";
 144                 }
 145
 146                 var type_args = get_type_arguments ();
 147                 if (type_args.size > 0) {
 148                         s += "<";
 149                         bool first = true;
 150                         foreach (DataType type_arg in type_args) {
 151                                 if (!first) {
 152                                         s += ",";
 153                                 } else {
 154                                         first = false;
 155                                 }
 156                                 if (!type_arg.value_owned) {
 157                                         s += "weak ";
 158                                 }
 159                                 s += type_arg.to_qualified_string (scope);
 160                         }
 161                         s += ">";
 162                 }
 163                 if (nullable) {
 164                         s += "?";
 165                 }
 166
 167                 return s;
 168         }
 169
 170         /**
 171          * Creates a shallow copy of this type reference.
 172          *
 173          * @return copy of this type reference
 174          */
 175         public abstract DataType copy ();
 176
 177         /**
 178          * Checks two type references for equality. May only be used with
 179          * resolved type references.
 180          *
 181          * @param type2 a type reference
 182          * @return      true if this type reference is equal to type2, false
 183          *              otherwise
 184          */
 185         public virtual bool equals (DataType type2) {
 186                 if (type2.is_disposable () != is_disposable ()) {
 187                         return false;
 188                 }
 189                 if (type2.nullable != nullable) {
 190                         return false;
 191                 }
 192                 if (type2.data_type != data_type) {
 193                         return false;
 194                 }
 195                 if (type2 is GenericType || this is GenericType) {
 196                         if (!(type2 is GenericType) || !(this is GenericType)) {
 197                                 return false;
 198                         }
 199                         if (!((GenericType) type2).type_parameter.equals (((GenericType) this).type_parameter)) {
 200                                 return false;
 201                         }
 202                 }
 203                 if (type2.floating_reference != floating_reference) {
 204                         return false;
 205                 }
 206
 207                 var type_args = get_type_arguments ();
 208                 var type2_args = type2.get_type_arguments ();
 209                 if (type2_args.size != type_args.size) {
 210                         return false;
 211                 }
 212
 213                 for (int i = 0; i < type_args.size; i++) {
 214                         if (!type2_args[i].equals (type_args[i]))
 215                                 return false;
 216                 }
 217
 218                 return true;
 219         }
 220
 221         /**
 222          * Checks whether this type reference is at least as strict as the
 223          * specified type reference type2.
 224          *
 225          * @param type2 a type reference
 226          * @return      true if this type reference is stricter or equal
 227          */
 228         public virtual bool stricter (DataType type2) {
 229                 if (type2.is_disposable () != is_disposable ()) {
 230                         return false;
 231                 }
 232
 233                 if (!type2.nullable && nullable) {
 234                         return false;
 235                 }
 236
 237                 /* temporarily ignore type parameters */
 238                 if (this is GenericType || type2 is GenericType) {
 239                         return true;
 240                 }
 241
 242                 if (type2.data_type != data_type) {
 243                         // FIXME: allow this type reference to refer to a
 244                         //        subtype of the type type2 is referring to
 245                         return false;
 246                 }
 247
 248                 if (type2.floating_reference != floating_reference) {
 249                         return false;
 250                 }
 251
 252                 return true;
 253         }
 254
 255         public override void replace_type (DataType old_type, DataType new_type) {
 256                 if (type_argument_list != null) {
 257                         for (int i = 0; i < type_argument_list.size; i++) {
 258                                 if (type_argument_list[i] == old_type) {
 259                                         type_argument_list[i] = new_type;
 260                                         return;
 261                                 }
 262                         }
 263                 }
 264         }
 265
 266         public virtual bool compatible (DataType target_type) {
 267                 if (CodeContext.get ().experimental_non_null && nullable && !target_type.nullable) {
 268                         return false;
 269                 }
 270
 271                 if (target_type.data_type != null) {
 272                         if (target_type.data_type.is_subtype_of (CodeContext.get ().analyzer.gvalue_type.data_type)) {
 273                                 // allow implicit conversion to GValue
 274                                 return true;
 275                         }
 276
 277                         if (target_type.data_type.is_subtype_of (CodeContext.get ().analyzer.gvariant_type.data_type)) {
 278                                 // allow implicit conversion to GVariant
 279                                 return true;
 280                         }
 281                 }
 282
 283                 if (target_type is PointerType) {
 284                         /* any reference or array type or pointer type can be cast to a generic pointer */
 285                         if (this is GenericType ||
 286                                 (data_type != null && (
 287                                         data_type.is_reference_type () ||
 288                                         this is DelegateType))) {
 289                                 return true;
 290                         }
 291
 292                         return false;
 293                 }
 294
 295                 /* temporarily ignore type parameters */
 296                 if (target_type is GenericType) {
 297                         return true;
 298                 }
 299
 300                 if (this is ArrayType != target_type is ArrayType) {
 301                         return false;
 302                 }
 303
 304                 if (data_type is Enum && target_type.data_type is Struct && ((Struct) target_type.data_type).is_integer_type ()) {
 305                         return true;
 306                 }
 307
 308                 if (data_type != null && target_type.data_type != null && data_type.is_subtype_of (target_type.data_type)) {
 309                         var base_type = SemanticAnalyzer.get_instance_base_type_for_member(this, target_type.data_type, this);
 310                         // check compatibility of generic type arguments
 311                         var base_type_args = base_type.get_type_arguments();
 312                         var target_type_args = target_type.get_type_arguments();
 313                         if (base_type_args.size == target_type_args.size) {
 314                                 for (int i = 0; i < base_type_args.size; i++) {
 315                                         // mutable generic types require type argument equality,
 316                                         // not just one way compatibility
 317                                         // as we do not currently have immutable generic container types,
 318                                         // the additional check would be very inconvenient, so we
 319                                         // skip the additional check for now
 320                                         if (!base_type_args[i].compatible (target_type_args[i])) {
 321                                                 return false;
 322                                         }
 323                                 }
 324                         }
 325                         return true;
 326                 }
 327
 328                 if (data_type is Struct && target_type.data_type is Struct) {
 329                         var expr_struct = (Struct) data_type;
 330                         var expect_struct = (Struct) target_type.data_type;
 331
 332                         /* integer types may be implicitly cast to floating point types */
 333                         if (expr_struct.is_integer_type () && expect_struct.is_floating_type ()) {
 334                                 return true;
 335                         }
 336
 337                         if ((expr_struct.is_integer_type () && expect_struct.is_integer_type ()) ||
 338                             (expr_struct.is_floating_type () && expect_struct.is_floating_type ())) {
 339                                 if (expr_struct.get_rank () <= expect_struct.get_rank ()) {
 340                                         return true;
 341                                 }
 342                         }
 343                 }
 344
 345                 return false;
 346         }
 347
 348         /**
 349          * Returns whether instances of this type are invokable.
 350          *
 351          * @return true if invokable, false otherwise
 352          */
 353         public virtual bool is_invokable () {
 354                 return false;
 355         }
 356
 357         /**
 358          * Returns the return type of this invokable.
 359          *
 360          * @return return type
 361          */
 362         public virtual DataType? get_return_type () {
 363                 return null;
 364         }
 365
 366         /**
 367          * Returns copy of the list of invocation parameters.
 368          *
 369          * @return parameter list
 370          */
 371         public virtual List<Parameter>? get_parameters () {
 372                 return null;
 373         }
 374
 375         public virtual bool is_reference_type_or_type_parameter () {
 376                 return (data_type != null &&
 377                         data_type.is_reference_type ()) ||
 378                        this is GenericType;
 379         }
 380
 381         public virtual bool is_array () {
 382                 return false;
 383         }
 384
 385         // check whether this type is at least as accessible as the specified symbol
 386         public virtual bool is_accessible (Symbol sym) {
 387                 foreach (var type_arg in get_type_arguments ()) {
 388                         if (!type_arg.is_accessible (sym)) {
 389                                 return false;
 390                         }
 391                 }
 392                 if (data_type != null) {
 393                         return data_type.is_accessible (sym);
 394                 }
 395                 return true;
 396         }
 397
 398         public virtual Symbol? get_member (string member_name) {
 399                 if (data_type != null) {
 400                         return SemanticAnalyzer.symbol_lookup_inherited (data_type, member_name);
 401                 }
 402                 return null;
 403         }
 404
 405         public virtual Symbol? get_pointer_member (string member_name) {
 406                 return null;
 407         }
 408
 409         /**
 410          * Checks whether this data type references a real struct. A real struct
 411          * is a struct which is not a simple (fundamental) type.
 412          */
 413         public virtual bool is_real_struct_type () {
 414                 var s = data_type as Struct;
 415                 if (s != null && !s.is_simple_type ()) {
 416                         return true;
 417                 }
 418                 return false;
 419         }
 420
 421         public bool is_real_non_null_struct_type () {
 422                 return is_real_struct_type () && !nullable;
 423         }
 424
 425         /**
 426          * Returns whether the value needs to be disposed, i.e. whether
 427          * allocated memory or other resources need to be released when
 428          * the value is no longer needed.
 429          */
 430         public virtual bool is_disposable () {
 431                 if (!value_owned) {
 432                         return false;
 433                 }
 434
 435                 if (is_reference_type_or_type_parameter ()) {
 436                         return true;
 437                 }
 438                 return false;
 439         }
 440
 441         public virtual DataType get_actual_type (DataType? derived_instance_type, List<DataType>? method_type_arguments, CodeNode node_reference) {
 442                 DataType result = this.copy ();
 443
 444                 if (derived_instance_type == null && method_type_arguments == null) {
 445                         return result;
 446                 }
 447
 448                 if (result is GenericType) {
 449                         result = SemanticAnalyzer.get_actual_type (derived_instance_type, method_type_arguments, (GenericType) result, node_reference);
 450                         // don't try to resolve type arguments of returned actual type
 451                         // they can never be resolved and are not related to the instance type
 452                 } else if (result.type_argument_list != null) {
 453                         // recursely get actual types for type arguments
 454                         for (int i = 0; i < result.type_argument_list.size; i++) {
 455                                 result.type_argument_list[i] = result.type_argument_list[i].get_actual_type (derived_instance_type, method_type_arguments, node_reference);
 456                         }
 457                 }
 458
 459                 return result;
 460         }
 461
 462         /**
 463          * Search for the type parameter in this formal type and match it in
 464          * value_type.
 465          */
 466         public virtual DataType? infer_type_argument (TypeParameter type_param, DataType value_type) {
 467                 var value_type_arg_it = value_type.get_type_arguments ().iterator ();
 468                 foreach (var formal_type_arg in this.get_type_arguments ()) {
 469                         if (value_type_arg_it.next ()) {
 470                                 var inferred_type = formal_type_arg.infer_type_argument (type_param, value_type_arg_it.get ());
 471                                 if (inferred_type != null) {
 472                                         return inferred_type;
 473                                 }
 474                         }
 475                 }
 476
 477                 return null;
 478         }
 479
 480         /**
 481          * Returns a stringified representation used for detailed error output
 482          *
 483          * @param override_name used as name if given
 484          * @return stringified representation
 485          */
 486         public virtual string to_prototype_string (string? override_name = null) {
 487                 return "%s%s".printf (is_weak () ? "unowned " : "", to_qualified_string ());
 488         }
 489
 490         public bool is_weak () {
 491                 if (this.value_owned) {
 492                         return false;
 493                 } else if (this is VoidType || this is PointerType) {
 494                         return false;
 495                 } else if (this is ValueType) {
 496                         if (this.nullable) {
 497                                 // nullable structs are heap allocated
 498                                 return true;
 499                         }
 500
 501                         // TODO return true for structs with destroy
 502                         return false;
 503                 }
 504
 505                 return true;
 506         }
 507 }