mcs/mcs/parameter.cs

   1 //
   2 // parameter.cs: Parameter definition.
   3 //
   4 // Author: Miguel de Icaza (miguel@gnu.org)
   5 //
   6 // Licensed under the terms of the GNU GPL
   7 //
   8 // (C) 2001 Ximian, Inc (http://www.ximian.com)
   9 //
  10 //
  11 //
  12 using System;
  13 using System.Reflection;
  14 using System.Reflection.Emit;
  15 using System.Collections;
  16
  17 namespace Mono.CSharp {
  18
  19         /// <summary>
  20         ///   Abstract Base class for parameters of a method.
  21         /// </summary>
  22         public abstract class ParameterBase : Attributable {
  23
  24                 protected ParameterBuilder builder;
  25
  26                 public ParameterBase (Attributes attrs)
  27                         : base (attrs)
  28                 {
  29                 }
  30
  31                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb)
  32                 {
  33                         if (a.Type == TypeManager.marshal_as_attr_type) {
  34                                 UnmanagedMarshal marshal = a.GetMarshal (this);
  35                                 if (marshal != null) {
  36                                         builder.SetMarshal (marshal);
  37                                 }
  38                                 return;
  39                         }
  40
  41                         if (a.Type.IsSubclassOf (TypeManager.security_attr_type)) {
  42                                 a.Error_InvalidSecurityParent ();
  43                                 return;
  44                         }
  45
  46                         builder.SetCustomAttribute (cb);
  47                 }
  48
  49                 public override bool IsClsCompliaceRequired(DeclSpace ds)
  50                 {
  51                         return false;
  52                 }
  53         }
  54
  55         /// <summary>
  56         /// Class for applying custom attributes on the return type
  57         /// </summary>
  58         public class ReturnParameter: ParameterBase {
  59                 public ReturnParameter (MethodBuilder mb, Location location):
  60                         base (null)
  61                 {
  62                         try {
  63                                 builder = mb.DefineParameter (0, ParameterAttributes.None, "");
  64                         }
  65                         catch (ArgumentOutOfRangeException) {
  66                                 Report.Warning (-28, location, "The Microsoft .NET Runtime 1.x does not permit setting custom attributes on the return type");
  67                         }
  68                 }
  69
  70                 public override void ApplyAttributeBuilder(Attribute a, CustomAttributeBuilder cb)
  71                 {
  72                         if (a.Type == TypeManager.cls_compliant_attribute_type) {
  73                                 Report.Warning (3023, 1, a.Location, "CLSCompliant attribute has no meaning when applied to return types. Try putting it on the method instead");
  74                         }
  75
  76                         // This occurs after Warning -28
  77                         if (builder == null)
  78                                 return;
  79
  80                         base.ApplyAttributeBuilder (a, cb);
  81                 }
  82
  83                 public override AttributeTargets AttributeTargets {
  84                         get {
  85                                 return AttributeTargets.ReturnValue;
  86                         }
  87                 }
  88
  89                 /// <summary>
  90                 /// Is never called
  91                 /// </summary>
  92                 public override string[] ValidAttributeTargets {
  93                         get {
  94                                 return null;
  95                         }
  96                 }
  97         }
  98
  99         /// <summary>
 100         /// Class for applying custom attributes on the implicit parameter type
 101         /// of the 'set' method in properties, and the 'add' and 'remove' methods in events.
 102         /// </summary>
 103         public class ImplicitParameter: ParameterBase {
 104                 public ImplicitParameter (MethodBuilder mb):
 105                         base (null)
 106                 {
 107                         builder = mb.DefineParameter (1, ParameterAttributes.None, "");
 108                 }
 109
 110                 public override AttributeTargets AttributeTargets {
 111                         get {
 112                                 return AttributeTargets.Parameter;
 113                         }
 114                 }
 115
 116                 /// <summary>
 117                 /// Is never called
 118                 /// </summary>
 119                 public override string[] ValidAttributeTargets {
 120                         get {
 121                                 return null;
 122                         }
 123                 }
 124         }
 125
 126         /// <summary>
 127         ///   Represents a single method parameter
 128         /// </summary>
 129
 130         //TODO: Add location member to this or base class for better error location and all methods simplification.
 131         public class Parameter : ParameterBase {
 132                 [Flags]
 133                 public enum Modifier : byte {
 134                         NONE    = 0,
 135                         REF     = 1,
 136                         OUT     = 2,
 137                         PARAMS  = 4,
 138                         // This is a flag which says that it's either REF or OUT.
 139                         ISBYREF = 8,
 140                         ARGLIST = 16
 141                 }
 142
 143                 static string[] attribute_targets = new string [] { "param" };
 144
 145                 public Expression TypeName;
 146                 public readonly Modifier ModFlags;
 147                 public readonly string Name;
 148                 Type parameter_type;
 149
 150                 EmitContext ec;  // because ApplyAtrribute doesn't have ec
 151
 152                 public Parameter (Expression type, string name, Modifier mod, Attributes attrs)
 153                         : base (attrs)
 154                 {
 155                         Name = name;
 156                         ModFlags = mod;
 157                         TypeName = type;
 158                 }
 159
 160                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb)
 161                 {
 162                         if (a.Type == TypeManager.in_attribute_type && Attributes == ParameterAttributes.Out) {
 163                                 Report.Error (36, a.Location, "Can not use [In] attribute on out parameter");
 164                                 return;
 165                         }
 166
 167                         if (a.Type == TypeManager.param_array_type) {
 168                                 Report.Error (674, a.Location, "Do not use 'System.ParamArrayAttribute'. Use the 'params' keyword instead");
 169                                 return;
 170                         }
 171
 172                         if (a.Type == TypeManager.out_attribute_type && (ModFlags & Modifier.REF) != 0 &&
 173                             !OptAttributes.Contains (TypeManager.in_attribute_type, ec)) {
 174                                 Report.Error (662, a.Location,
 175                                         "'{0}' cannot specify only Out attribute on a ref parameter. Use both In and Out attributes, or neither", GetSignatureForError ());
 176                                 return;
 177                         }
 178
 179                         if (a.Type == TypeManager.cls_compliant_attribute_type) {
 180                                 Report.Warning (3022, 1, a.Location, "CLSCompliant attribute has no meaning when applied to parameters. Try putting it on the method instead");
 181                         }
 182
 183                         base.ApplyAttributeBuilder (a, cb);
 184                 }
 185
 186                 // <summary>
 187                 //   Resolve is used in method definitions
 188                 // </summary>
 189                 public bool Resolve (EmitContext ec, Location l)
 190                 {
 191                         this.ec = ec;
 192
 193                         TypeExpr texpr = TypeName.ResolveAsTypeTerminal (ec, false);
 194                         if (texpr == null)
 195                                 return false;
 196
 197                         parameter_type = texpr.ResolveType (ec);
 198
 199                         if (parameter_type.IsAbstract && parameter_type.IsSealed) {
 200                                 Report.Error (721, l, "'{0}': static types cannot be used as parameters", GetSignatureForError ());
 201                                 return false;
 202                         }
 203
 204                         if (parameter_type == TypeManager.void_type){
 205                                 Report.Error (1536, l, "Invalid parameter type 'void'");
 206                                 return false;
 207                         }
 208
 209                         if ((ModFlags & Parameter.Modifier.ISBYREF) != 0){
 210                                 if (parameter_type == TypeManager.typed_reference_type ||
 211                                     parameter_type == TypeManager.arg_iterator_type){
 212                                         Report.Error (1601, l,
 213                                                       "out or ref parameter can not be of type TypedReference or ArgIterator");
 214                                         return false;
 215                                 }
 216                         }
 217
 218                         return parameter_type != null;
 219                 }
 220
 221                 public Type ExternalType ()
 222                 {
 223                         if ((ModFlags & Parameter.Modifier.ISBYREF) != 0)
 224                                 return TypeManager.GetReferenceType (parameter_type);
 225
 226                         return parameter_type;
 227                 }
 228
 229                 public Type ParameterType {
 230                         get {
 231                                 return parameter_type;
 232                         }
 233                 }
 234
 235                 public ParameterAttributes Attributes {
 236                         get {
 237                                 int flags = ((int) ModFlags) & ~((int) Parameter.Modifier.ISBYREF);
 238                                 switch ((Modifier) flags) {
 239                                 case Modifier.NONE:
 240                                         return ParameterAttributes.None;
 241                                 case Modifier.REF:
 242                                         return ParameterAttributes.None;
 243                                 case Modifier.OUT:
 244                                         return ParameterAttributes.Out;
 245                                 case Modifier.PARAMS:
 246                                         return 0;
 247                                 }
 248
 249                                 return ParameterAttributes.None;
 250                         }
 251                 }
 252
 253                 public override AttributeTargets AttributeTargets {
 254                         get {
 255                                 return AttributeTargets.Parameter;
 256                         }
 257                 }
 258
 259                 /// <summary>
 260                 ///   Returns the signature for this parameter evaluating it on the
 261                 ///   @tc context
 262                 /// </summary>
 263                 public string GetSignature (EmitContext ec, Location loc)
 264                 {
 265                         if (parameter_type == null){
 266                                 if (!Resolve (ec, loc))
 267                                         return null;
 268                         }
 269
 270                         return ExternalType ().FullName;
 271                 }
 272
 273                 public string GetSignatureForError ()
 274                 {
 275                         string typeName;
 276                         if (parameter_type != null)
 277                                 typeName = TypeManager.CSharpName (parameter_type);
 278                         else if (TypeName.Type != null)
 279                                 typeName = TypeManager.CSharpName (TypeName.Type);
 280                         else
 281                                 typeName = TypeName.ToString ();
 282
 283                         switch (ModFlags & unchecked (~Modifier.ISBYREF)) {
 284                                 case Modifier.OUT:
 285                                         return "out " + typeName;
 286                                 case Modifier.PARAMS:
 287                                         return "params " + typeName;
 288                                 case Modifier.REF:
 289                                         return "ref " + typeName;
 290                         }
 291                         return typeName;
 292                 }
 293
 294                 public void DefineParameter (EmitContext ec, MethodBuilder mb, ConstructorBuilder cb, int index, Location loc)
 295                 {
 296                         ParameterAttributes par_attr = Attributes;
 297
 298                         if (mb == null)
 299                                 builder = cb.DefineParameter (index, par_attr, Name);
 300                         else
 301                                 builder = mb.DefineParameter (index, par_attr, Name);
 302
 303                         if (OptAttributes != null) {
 304                                 OptAttributes.Emit (ec, this);
 305                         }
 306                 }
 307
 308                 public override string[] ValidAttributeTargets {
 309                         get {
 310                                 return attribute_targets;
 311                         }
 312                 }
 313         }
 314
 315         /// <summary>
 316         ///   Represents the methods parameters
 317         /// </summary>
 318         public class Parameters {
 319                 public Parameter [] FixedParameters;
 320                 public readonly Parameter ArrayParameter;
 321                 public readonly bool HasArglist;
 322                 string signature;
 323                 Type [] types;
 324                 Location loc;
 325
 326                 static Parameters empty_parameters;
 327
 328                 public Parameters (Parameter [] fixed_parameters, Parameter array_parameter, Location l)
 329                 {
 330                         FixedParameters = fixed_parameters;
 331                         ArrayParameter  = array_parameter;
 332                         loc = l;
 333                 }
 334
 335                 public Parameters (Parameter [] fixed_parameters, bool has_arglist, Location l)
 336                 {
 337                         FixedParameters = fixed_parameters;
 338                         HasArglist = has_arglist;
 339                         loc = l;
 340                 }
 341
 342                 /// <summary>
 343                 ///   This is used to reuse a set of empty parameters, because they
 344                 ///   are common
 345                 /// </summary>
 346                 public static Parameters EmptyReadOnlyParameters {
 347                         get {
 348                                 if (empty_parameters == null)
 349                                         empty_parameters = new Parameters (null, null, Location.Null);
 350
 351                                 return empty_parameters;
 352                         }
 353                 }
 354
 355                 public bool Empty {
 356                         get {
 357                                 return (FixedParameters == null) && (ArrayParameter == null);
 358                         }
 359                 }
 360
 361                 public void ComputeSignature (EmitContext ec)
 362                 {
 363                         signature = "";
 364                         if (FixedParameters != null){
 365                                 for (int i = 0; i < FixedParameters.Length; i++){
 366                                         Parameter par = FixedParameters [i];
 367
 368                                         signature += par.GetSignature (ec, loc);
 369                                 }
 370                         }
 371                         //
 372                         // Note: as per the spec, the `params' arguments (ArrayParameter)
 373                         // are not used in the signature computation for a method
 374                         //
 375                 }
 376
 377                 void Error_DuplicateParameterName (string name)
 378                 {
 379                         Report.Error (
 380                                 100, loc, "The parameter name `" + name + "' is a duplicate");
 381                 }
 382
 383                 public bool VerifyArgs ()
 384                 {
 385                         int count;
 386                         int i, j;
 387
 388                         if (FixedParameters == null)
 389                                 return true;
 390
 391                         count = FixedParameters.Length;
 392                         string array_par_name = ArrayParameter != null ? ArrayParameter.Name : null;
 393
 394                         for (i = 0; i < count; i++){
 395                                 string base_name = FixedParameters [i].Name;
 396                                 for (j = i + 1; j < count; j++){
 397                                         if (base_name != FixedParameters [j].Name)
 398                                                 continue;
 399                                         Error_DuplicateParameterName (base_name);
 400                                         return false;
 401                                 }
 402
 403                                 if (base_name == array_par_name){
 404                                         Error_DuplicateParameterName (base_name);
 405                                         return false;
 406                                 }
 407                         }
 408                         return true;
 409                 }
 410
 411                 /// <summary>
 412                 ///    Returns the signature of the Parameters evaluated in
 413                 ///    the @ec EmitContext
 414                 /// </summary>
 415                 public string GetSignature (EmitContext ec)
 416                 {
 417                         if (signature == null){
 418                                 VerifyArgs ();
 419                                 ComputeSignature (ec);
 420                         }
 421
 422                         return signature;
 423                 }
 424
 425                 /// <summary>
 426                 ///    Returns the paramenter information based on the name
 427                 /// </summary>
 428                 public Parameter GetParameterByName (string name, out int idx)
 429                 {
 430                         idx = 0;
 431                         int i = 0;
 432
 433                         if (FixedParameters != null){
 434                                 foreach (Parameter par in FixedParameters){
 435                                         if (par.Name == name){
 436                                                 idx = i;
 437                                                 return par;
 438                                         }
 439                                         i++;
 440                                 }
 441                         }
 442
 443                         if (ArrayParameter != null){
 444                                 if (name == ArrayParameter.Name){
 445                                         idx = i;
 446                                         return ArrayParameter;
 447                                 }
 448                         }
 449
 450                         return null;
 451                 }
 452
 453                 public Parameter GetParameterByName (string name)
 454                 {
 455                         int idx;
 456
 457                         return GetParameterByName (name, out idx);
 458                 }
 459
 460                 bool ComputeParameterTypes (EmitContext ec)
 461                 {
 462                         int extra = (ArrayParameter != null) ? 1 : 0;
 463                         int i = 0;
 464                         int pc;
 465
 466                         if (FixedParameters == null)
 467                                 pc = extra;
 468                         else
 469                                 pc = extra + FixedParameters.Length;
 470
 471                         types = new Type [pc];
 472
 473                         if (!VerifyArgs ()){
 474                                 FixedParameters = null;
 475                                 return false;
 476                         }
 477
 478                         bool failed = false;
 479                         if (FixedParameters != null){
 480                                 foreach (Parameter p in FixedParameters){
 481                                         Type t = null;
 482
 483                                         if (p.Resolve (ec, loc))
 484                                                 t = p.ExternalType ();
 485                                         else
 486                                                 failed = true;
 487
 488                                         types [i] = t;
 489                                         i++;
 490                                 }
 491                         }
 492
 493                         if (extra > 0){
 494                                 if (ArrayParameter.Resolve (ec, loc))
 495                                         types [i] = ArrayParameter.ExternalType ();
 496                                 else
 497                                         failed = true;
 498                         }
 499
 500                         if (failed){
 501                                 types = null;
 502                                 return false;
 503                         }
 504
 505                         return true;
 506                 }
 507
 508                 //
 509                 // This variant is used by Delegates, because they need to
 510                 // resolve/define names, instead of the plain LookupType
 511                 //
 512                 public bool ComputeAndDefineParameterTypes (EmitContext ec)
 513                 {
 514                         bool old_type_resolving = ec.ResolvingTypeTree;
 515                         ec.ResolvingTypeTree = true;
 516                         bool retval = ComputeParameterTypes (ec);
 517                         ec.ResolvingTypeTree = old_type_resolving;
 518                         return retval;
 519                 }
 520
 521                 /// <summary>
 522                 ///   Returns the argument types as an array
 523                 /// </summary>
 524                 static Type [] no_types = new Type [0];
 525
 526                 public Type [] GetParameterInfo (EmitContext ec)
 527                 {
 528                         if (types != null)
 529                                 return types;
 530
 531                         if (FixedParameters == null && ArrayParameter == null)
 532                                 return no_types;
 533
 534                         if (ComputeParameterTypes (ec) == false){
 535                                 types = null;
 536                                 return null;
 537                         }
 538
 539                         return types;
 540                 }
 541
 542                 /// <summary>
 543                 ///   Returns the type of a given parameter, and stores in the `is_out'
 544                 ///   boolean whether this is an out or ref parameter.
 545                 ///
 546                 ///   Note that the returned type will not contain any dereference in this
 547                 ///   case (ie, you get "int" for a ref int instead of "int&"
 548                 /// </summary>
 549                 public Type GetParameterInfo (EmitContext ec, int idx, out Parameter.Modifier mod)
 550                 {
 551                         mod = Parameter.Modifier.NONE;
 552
 553                         if (!VerifyArgs ()){
 554                                 FixedParameters = null;
 555                                 return null;
 556                         }
 557
 558                         if (FixedParameters == null && ArrayParameter == null)
 559                                 return null;
 560
 561                         if (types == null)
 562                                 if (ComputeParameterTypes (ec) == false)
 563                                         return null;
 564
 565                         //
 566                         // If this is a request for the variable lenght arg.
 567                         //
 568                         int array_idx = (FixedParameters != null ? FixedParameters.Length : 0);
 569                         if (idx == array_idx)
 570                                 return types [idx];
 571
 572                         //
 573                         // Otherwise, it is a fixed parameter
 574                         //
 575                         Parameter p = FixedParameters [idx];
 576                         mod = p.ModFlags;
 577
 578                         if ((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) != 0)
 579                                 mod |= Parameter.Modifier.ISBYREF;
 580
 581                         return p.ParameterType;
 582                 }
 583
 584                 public CallingConventions GetCallingConvention ()
 585                 {
 586                         if (HasArglist)
 587                                 return CallingConventions.VarArgs;
 588                         else
 589                                 return CallingConventions.Standard;
 590                 }
 591
 592                 //
 593                 // The method's attributes are passed in because we need to extract
 594                 // the "return:" attribute from there to apply on the return type
 595                 //
 596                 public void LabelParameters (EmitContext ec,
 597                         MethodBase builder,
 598                         Location loc) {
 599                         //
 600                         // Define each type attribute (in/out/ref) and
 601                         // the argument names.
 602                         //
 603                         int i = 0;
 604
 605                         MethodBuilder mb = builder as MethodBuilder;
 606                         ConstructorBuilder cb = builder as ConstructorBuilder;
 607
 608                         if (FixedParameters != null) {
 609                                 for (i = 0; i < FixedParameters.Length; i++) {
 610                                         FixedParameters [i].DefineParameter (ec, mb, cb, i + 1, loc);
 611                                 }
 612                         }
 613
 614                         if (ArrayParameter != null){
 615                                 ParameterBuilder pb;
 616                                 Parameter array_param = ArrayParameter;
 617
 618                                 if (mb == null)
 619                                         pb = cb.DefineParameter (
 620                                                 i + 1, array_param.Attributes,
 621                                                 array_param.Name);
 622                                 else
 623                                         pb = mb.DefineParameter (
 624                                                 i + 1, array_param.Attributes,
 625                                                 array_param.Name);
 626
 627                                 CustomAttributeBuilder a = new CustomAttributeBuilder (
 628                                         TypeManager.cons_param_array_attribute, new object [0]);
 629
 630                                 pb.SetCustomAttribute (a);
 631                         }
 632                 }
 633         }
 634 }