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                 public Parameter (Expression type, string name, Modifier mod, Attributes attrs)
 151                         : base (attrs)
 152                 {
 153                         Name = name;
 154                         ModFlags = mod;
 155                         TypeName = type;
 156                 }
 157
 158                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb)
 159                 {
 160                         if (a.Type == TypeManager.param_array_type) {
 161                                 Report.Error (674, a.Location, "Do not use 'System.ParamArrayAttribute'. Use the 'params' keyword instead");
 162                                 return;
 163                         }
 164
 165                         if (a.Type == TypeManager.cls_compliant_attribute_type) {
 166                                 Report.Warning (3022, 1, a.Location, "CLSCompliant attribute has no meaning when applied to parameters. Try putting it on the method instead");
 167                         }
 168
 169                         base.ApplyAttributeBuilder (a, cb);
 170                 }
 171
 172                 // <summary>
 173                 //   Resolve is used in method definitions
 174                 // </summary>
 175                 public bool Resolve (EmitContext ec, Location l)
 176                 {
 177                         TypeExpr texpr = TypeName.ResolveAsTypeTerminal (ec, false);
 178                         if (texpr == null)
 179                                 return false;
 180
 181                         parameter_type = texpr.ResolveType (ec);
 182
 183                         if (parameter_type.IsAbstract && parameter_type.IsSealed) {
 184                                 Report.Error (721, l, "'{0}': static types cannot be used as parameters", GetSignatureForError ());
 185                                 return false;
 186                         }
 187
 188                         if (parameter_type == TypeManager.void_type){
 189                                 Report.Error (1536, l, "Invalid parameter type 'void'");
 190                                 return false;
 191                         }
 192
 193                         if ((ModFlags & Parameter.Modifier.ISBYREF) != 0){
 194                                 if (parameter_type == TypeManager.typed_reference_type ||
 195                                     parameter_type == TypeManager.arg_iterator_type){
 196                                         Report.Error (1601, l,
 197                                                       "out or ref parameter can not be of type TypedReference or ArgIterator");
 198                                         return false;
 199                                 }
 200                         }
 201
 202                         return parameter_type != null;
 203                 }
 204
 205                 public Type ExternalType ()
 206                 {
 207                         if ((ModFlags & Parameter.Modifier.ISBYREF) != 0)
 208                                 return TypeManager.GetReferenceType (parameter_type);
 209
 210                         return parameter_type;
 211                 }
 212
 213                 public Type ParameterType {
 214                         get {
 215                                 return parameter_type;
 216                         }
 217                 }
 218
 219                 public ParameterAttributes Attributes {
 220                         get {
 221                                 int flags = ((int) ModFlags) & ~((int) Parameter.Modifier.ISBYREF);
 222                                 switch ((Modifier) flags) {
 223                                 case Modifier.NONE:
 224                                         return ParameterAttributes.None;
 225                                 case Modifier.REF:
 226                                         return ParameterAttributes.None;
 227                                 case Modifier.OUT:
 228                                         return ParameterAttributes.Out;
 229                                 case Modifier.PARAMS:
 230                                         return 0;
 231                                 }
 232
 233                                 return ParameterAttributes.None;
 234                         }
 235                 }
 236
 237                 public override AttributeTargets AttributeTargets {
 238                         get {
 239                                 return AttributeTargets.Parameter;
 240                         }
 241                 }
 242
 243                 /// <summary>
 244                 ///   Returns the signature for this parameter evaluating it on the
 245                 ///   @tc context
 246                 /// </summary>
 247                 public string GetSignature (EmitContext ec, Location loc)
 248                 {
 249                         if (parameter_type == null){
 250                                 if (!Resolve (ec, loc))
 251                                         return null;
 252                         }
 253
 254                         return ExternalType ().FullName;
 255                 }
 256
 257                 public string GetSignatureForError ()
 258                 {
 259                         string typeName;
 260                         if (parameter_type != null)
 261                                 typeName = TypeManager.CSharpName (parameter_type);
 262                         else if (TypeName.Type != null)
 263                                 typeName = TypeManager.CSharpName (TypeName.Type);
 264                         else
 265                                 typeName = TypeName.ToString ();
 266
 267                         switch (ModFlags & unchecked (~Modifier.ISBYREF)) {
 268                                 case Modifier.OUT:
 269                                         return "out " + typeName;
 270                                 case Modifier.PARAMS:
 271                                         return "params " + typeName;
 272                                 case Modifier.REF:
 273                                         return "ref " + typeName;
 274                         }
 275                         return typeName;
 276                 }
 277
 278                 public void DefineParameter (EmitContext ec, MethodBuilder mb, ConstructorBuilder cb, int index, Location loc)
 279                 {
 280                         ParameterAttributes par_attr = Attributes;
 281
 282                         if (mb == null)
 283                                 builder = cb.DefineParameter (index, par_attr, Name);
 284                         else
 285                                 builder = mb.DefineParameter (index, par_attr, Name);
 286
 287                         if (OptAttributes != null) {
 288                                 OptAttributes.Emit (ec, this);
 289
 290                                 if (par_attr == ParameterAttributes.Out){
 291                                         if (OptAttributes.Contains (TypeManager.in_attribute_type, ec))
 292                                                 Report.Error (36, loc,  "Can not use [In] attribute on out parameter");
 293                                 }
 294                         }
 295                 }
 296
 297                 public override string[] ValidAttributeTargets {
 298                         get {
 299                                 return attribute_targets;
 300                         }
 301                 }
 302         }
 303
 304         /// <summary>
 305         ///   Represents the methods parameters
 306         /// </summary>
 307         public class Parameters {
 308                 public Parameter [] FixedParameters;
 309                 public readonly Parameter ArrayParameter;
 310                 public readonly bool HasArglist;
 311                 string signature;
 312                 Type [] types;
 313                 Location loc;
 314
 315                 static Parameters empty_parameters;
 316
 317                 public Parameters (Parameter [] fixed_parameters, Parameter array_parameter, Location l)
 318                 {
 319                         FixedParameters = fixed_parameters;
 320                         ArrayParameter  = array_parameter;
 321                         loc = l;
 322                 }
 323
 324                 public Parameters (Parameter [] fixed_parameters, bool has_arglist, Location l)
 325                 {
 326                         FixedParameters = fixed_parameters;
 327                         HasArglist = has_arglist;
 328                         loc = l;
 329                 }
 330
 331                 /// <summary>
 332                 ///   This is used to reuse a set of empty parameters, because they
 333                 ///   are common
 334                 /// </summary>
 335                 public static Parameters EmptyReadOnlyParameters {
 336                         get {
 337                                 if (empty_parameters == null)
 338                                         empty_parameters = new Parameters (null, null, Location.Null);
 339
 340                                 return empty_parameters;
 341                         }
 342                 }
 343
 344                 public bool Empty {
 345                         get {
 346                                 return (FixedParameters == null) && (ArrayParameter == null);
 347                         }
 348                 }
 349
 350                 public void ComputeSignature (EmitContext ec)
 351                 {
 352                         signature = "";
 353                         if (FixedParameters != null){
 354                                 for (int i = 0; i < FixedParameters.Length; i++){
 355                                         Parameter par = FixedParameters [i];
 356
 357                                         signature += par.GetSignature (ec, loc);
 358                                 }
 359                         }
 360                         //
 361                         // Note: as per the spec, the `params' arguments (ArrayParameter)
 362                         // are not used in the signature computation for a method
 363                         //
 364                 }
 365
 366                 void Error_DuplicateParameterName (string name)
 367                 {
 368                         Report.Error (
 369                                 100, loc, "The parameter name `" + name + "' is a duplicate");
 370                 }
 371
 372                 public bool VerifyArgs ()
 373                 {
 374                         int count;
 375                         int i, j;
 376
 377                         if (FixedParameters == null)
 378                                 return true;
 379
 380                         count = FixedParameters.Length;
 381                         string array_par_name = ArrayParameter != null ? ArrayParameter.Name : null;
 382
 383                         for (i = 0; i < count; i++){
 384                                 string base_name = FixedParameters [i].Name;
 385                                 for (j = i + 1; j < count; j++){
 386                                         if (base_name != FixedParameters [j].Name)
 387                                                 continue;
 388                                         Error_DuplicateParameterName (base_name);
 389                                         return false;
 390                                 }
 391
 392                                 if (base_name == array_par_name){
 393                                         Error_DuplicateParameterName (base_name);
 394                                         return false;
 395                                 }
 396                         }
 397                         return true;
 398                 }
 399
 400                 /// <summary>
 401                 ///    Returns the signature of the Parameters evaluated in
 402                 ///    the @ec EmitContext
 403                 /// </summary>
 404                 public string GetSignature (EmitContext ec)
 405                 {
 406                         if (signature == null){
 407                                 VerifyArgs ();
 408                                 ComputeSignature (ec);
 409                         }
 410
 411                         return signature;
 412                 }
 413
 414                 /// <summary>
 415                 ///    Returns the paramenter information based on the name
 416                 /// </summary>
 417                 public Parameter GetParameterByName (string name, out int idx)
 418                 {
 419                         idx = 0;
 420                         int i = 0;
 421
 422                         if (FixedParameters != null){
 423                                 foreach (Parameter par in FixedParameters){
 424                                         if (par.Name == name){
 425                                                 idx = i;
 426                                                 return par;
 427                                         }
 428                                         i++;
 429                                 }
 430                         }
 431
 432                         if (ArrayParameter != null){
 433                                 if (name == ArrayParameter.Name){
 434                                         idx = i;
 435                                         return ArrayParameter;
 436                                 }
 437                         }
 438
 439                         return null;
 440                 }
 441
 442                 public Parameter GetParameterByName (string name)
 443                 {
 444                         int idx;
 445
 446                         return GetParameterByName (name, out idx);
 447                 }
 448
 449                 bool ComputeParameterTypes (EmitContext ec)
 450                 {
 451                         int extra = (ArrayParameter != null) ? 1 : 0;
 452                         int i = 0;
 453                         int pc;
 454
 455                         if (FixedParameters == null)
 456                                 pc = extra;
 457                         else
 458                                 pc = extra + FixedParameters.Length;
 459
 460                         types = new Type [pc];
 461
 462                         if (!VerifyArgs ()){
 463                                 FixedParameters = null;
 464                                 return false;
 465                         }
 466
 467                         bool failed = false;
 468                         if (FixedParameters != null){
 469                                 foreach (Parameter p in FixedParameters){
 470                                         Type t = null;
 471
 472                                         if (p.Resolve (ec, loc))
 473                                                 t = p.ExternalType ();
 474                                         else
 475                                                 failed = true;
 476
 477                                         types [i] = t;
 478                                         i++;
 479                                 }
 480                         }
 481
 482                         if (extra > 0){
 483                                 if (ArrayParameter.Resolve (ec, loc))
 484                                         types [i] = ArrayParameter.ExternalType ();
 485                                 else
 486                                         failed = true;
 487                         }
 488
 489                         if (failed){
 490                                 types = null;
 491                                 return false;
 492                         }
 493
 494                         return true;
 495                 }
 496
 497                 //
 498                 // This variant is used by Delegates, because they need to
 499                 // resolve/define names, instead of the plain LookupType
 500                 //
 501                 public bool ComputeAndDefineParameterTypes (EmitContext ec)
 502                 {
 503                         bool old_type_resolving = ec.ResolvingTypeTree;
 504                         ec.ResolvingTypeTree = true;
 505                         bool retval = ComputeParameterTypes (ec);
 506                         ec.ResolvingTypeTree = old_type_resolving;
 507                         return retval;
 508                 }
 509
 510                 /// <summary>
 511                 ///   Returns the argument types as an array
 512                 /// </summary>
 513                 static Type [] no_types = new Type [0];
 514
 515                 public Type [] GetParameterInfo (EmitContext ec)
 516                 {
 517                         if (types != null)
 518                                 return types;
 519
 520                         if (FixedParameters == null && ArrayParameter == null)
 521                                 return no_types;
 522
 523                         if (ComputeParameterTypes (ec) == false){
 524                                 types = null;
 525                                 return null;
 526                         }
 527
 528                         return types;
 529                 }
 530
 531                 /// <summary>
 532                 ///   Returns the type of a given parameter, and stores in the `is_out'
 533                 ///   boolean whether this is an out or ref parameter.
 534                 ///
 535                 ///   Note that the returned type will not contain any dereference in this
 536                 ///   case (ie, you get "int" for a ref int instead of "int&"
 537                 /// </summary>
 538                 public Type GetParameterInfo (EmitContext ec, int idx, out Parameter.Modifier mod)
 539                 {
 540                         mod = Parameter.Modifier.NONE;
 541
 542                         if (!VerifyArgs ()){
 543                                 FixedParameters = null;
 544                                 return null;
 545                         }
 546
 547                         if (FixedParameters == null && ArrayParameter == null)
 548                                 return null;
 549
 550                         if (types == null)
 551                                 if (ComputeParameterTypes (ec) == false)
 552                                         return null;
 553
 554                         //
 555                         // If this is a request for the variable lenght arg.
 556                         //
 557                         int array_idx = (FixedParameters != null ? FixedParameters.Length : 0);
 558                         if (idx == array_idx)
 559                                 return types [idx];
 560
 561                         //
 562                         // Otherwise, it is a fixed parameter
 563                         //
 564                         Parameter p = FixedParameters [idx];
 565                         mod = p.ModFlags;
 566
 567                         if ((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) != 0)
 568                                 mod |= Parameter.Modifier.ISBYREF;
 569
 570                         return p.ParameterType;
 571                 }
 572
 573                 public CallingConventions GetCallingConvention ()
 574                 {
 575                         if (HasArglist)
 576                                 return CallingConventions.VarArgs;
 577                         else
 578                                 return CallingConventions.Standard;
 579                 }
 580
 581                 //
 582                 // The method's attributes are passed in because we need to extract
 583                 // the "return:" attribute from there to apply on the return type
 584                 //
 585                 public void LabelParameters (EmitContext ec,
 586                         MethodBase builder,
 587                         Location loc) {
 588                         //
 589                         // Define each type attribute (in/out/ref) and
 590                         // the argument names.
 591                         //
 592                         int i = 0;
 593
 594                         MethodBuilder mb = builder as MethodBuilder;
 595                         ConstructorBuilder cb = builder as ConstructorBuilder;
 596
 597                         if (FixedParameters != null) {
 598                                 for (i = 0; i < FixedParameters.Length; i++) {
 599                                         FixedParameters [i].DefineParameter (ec, mb, cb, i + 1, loc);
 600                                 }
 601                         }
 602
 603                         if (ArrayParameter != null){
 604                                 ParameterBuilder pb;
 605                                 Parameter array_param = ArrayParameter;
 606
 607                                 if (mb == null)
 608                                         pb = cb.DefineParameter (
 609                                                 i + 1, array_param.Attributes,
 610                                                 array_param.Name);
 611                                 else
 612                                         pb = mb.DefineParameter (
 613                                                 i + 1, array_param.Attributes,
 614                                                 array_param.Name);
 615
 616                                 CustomAttributeBuilder a = new CustomAttributeBuilder (
 617                                         TypeManager.cons_param_array_attribute, new object [0]);
 618
 619                                 pb.SetCustomAttribute (a);
 620                         }
 621                 }
 622         }
 623 }