mcs/gmcs/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                         // This occurs after Warning -28
  73                         if (builder == null)
  74                                 return;
  75
  76                         base.ApplyAttributeBuilder (a, cb);
  77                 }
  78
  79                 public override AttributeTargets AttributeTargets {
  80                         get {
  81                                 return AttributeTargets.ReturnValue;
  82                         }
  83                 }
  84
  85                 /// <summary>
  86                 /// Is never called
  87                 /// </summary>
  88                 public override string[] ValidAttributeTargets {
  89                         get {
  90                                 return null;
  91                         }
  92                 }
  93         }
  94
  95         /// <summary>
  96        /// Class for applying custom attributes on the implicit parameter type
  97        /// of the 'set' method in properties, and the 'add' and 'remove' methods in events.
  98         /// </summary>
  99        public class ImplicitParameter: ParameterBase {
 100                public ImplicitParameter (MethodBuilder mb):
 101                         base (null)
 102                 {
 103                         builder = mb.DefineParameter (1, ParameterAttributes.None, "");
 104                 }
 105
 106                 public override AttributeTargets AttributeTargets {
 107                         get {
 108                                 return AttributeTargets.Parameter;
 109                         }
 110                 }
 111
 112                 /// <summary>
 113                 /// Is never called
 114                 /// </summary>
 115                 public override string[] ValidAttributeTargets {
 116                         get {
 117                                 return null;
 118                         }
 119         }
 120         }
 121
 122
 123         /// <summary>
 124         ///   Represents a single method parameter
 125         /// </summary>
 126
 127         //TODO: Add location member to this or base class for better error location and all methods simplification.
 128         public class Parameter : ParameterBase {
 129                 [Flags]
 130                 public enum Modifier : byte {
 131                         NONE    = 0,
 132                         REF     = 1,
 133                         OUT     = 2,
 134                         PARAMS  = 4,
 135                         // This is a flag which says that it's either REF or OUT.
 136                         ISBYREF = 8,
 137                         ARGLIST = 16
 138                 }
 139
 140                 static string[] attribute_targets = new string [] { "param" };
 141
 142                 public Expression TypeName;
 143                 public readonly Modifier ModFlags;
 144                 public readonly string Name;
 145                 GenericConstraints constraints;
 146                 Type parameter_type;
 147
 148                 public Parameter (Expression type, string name, Modifier mod, Attributes attrs)
 149                         : base (attrs)
 150                 {
 151                         Name = name;
 152                         ModFlags = mod;
 153                         TypeName = type;
 154                 }
 155
 156                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb)
 157                 {
 158                         if (a.Type == TypeManager.param_array_type) {
 159                                 Report.Error (674, a.Location, "Do not use 'System.ParamArrayAttribute'. Use the 'params' keyword instead");
 160                                 return;
 161                         }
 162                         base.ApplyAttributeBuilder (a, cb);
 163                 }
 164
 165                 // <summary>
 166                 //   Resolve is used in method definitions
 167                 // </summary>
 168                 public bool Resolve (EmitContext ec, Location l)
 169                 {
 170                         TypeExpr texpr = TypeName.ResolveAsTypeTerminal (ec);
 171                         if (texpr == null)
 172                                 return false;
 173
 174                         TypeParameterExpr tparam = texpr as TypeParameterExpr;
 175                         if (tparam != null)
 176                                 constraints = tparam.TypeParameter.Constraints;
 177
 178                         parameter_type = texpr.Type;
 179
 180                         if (parameter_type.IsAbstract && parameter_type.IsSealed) {
 181                                 Report.Error (721, l, "'{0}': static types cannot be used as parameters", GetSignatureForError ());
 182                                 return false;
 183                         }
 184
 185                         if (parameter_type == TypeManager.void_type){
 186                                 Report.Error (1536, l, "`void' parameter is not permitted");
 187                                 return false;
 188                         }
 189
 190                         if ((ModFlags & Parameter.Modifier.ISBYREF) != 0){
 191                                 if (parameter_type == TypeManager.typed_reference_type ||
 192                                     parameter_type == TypeManager.arg_iterator_type){
 193                                         Report.Error (1601, l,
 194                                                       "out or ref parameter can not be of type TypedReference or ArgIterator");
 195                                         return false;
 196                                 }
 197                         }
 198
 199                         return parameter_type != null;
 200                 }
 201
 202                 public Type ExternalType ()
 203                 {
 204                         if ((ModFlags & Parameter.Modifier.ISBYREF) != 0)
 205                                 return TypeManager.GetReferenceType (parameter_type);
 206
 207                         return parameter_type;
 208                 }
 209
 210                 public Type ParameterType {
 211                         get {
 212                                 return parameter_type;
 213                         }
 214                 }
 215
 216                 public GenericConstraints GenericConstraints {
 217                         get {
 218                                 return constraints;
 219                         }
 220                 }
 221
 222                 public ParameterAttributes Attributes {
 223                         get {
 224                                 int flags = ((int) ModFlags) & ~((int) Parameter.Modifier.ISBYREF);
 225                                 switch ((Modifier) flags) {
 226                                 case Modifier.NONE:
 227                                         return ParameterAttributes.None;
 228                                 case Modifier.REF:
 229                                         return ParameterAttributes.None;
 230                                 case Modifier.OUT:
 231                                         return ParameterAttributes.Out;
 232                                 case Modifier.PARAMS:
 233                                         return 0;
 234                                 }
 235
 236                                 return ParameterAttributes.None;
 237                         }
 238                 }
 239
 240                 public static ParameterAttributes GetParameterAttributes (Modifier mod)
 241                 {
 242                         int flags = ((int) mod) & ~((int) Parameter.Modifier.ISBYREF);
 243                         switch ((Modifier) flags) {
 244                         case Modifier.NONE:
 245                                 return ParameterAttributes.None;
 246                         case Modifier.REF:
 247                                 return ParameterAttributes.None;
 248                         case Modifier.OUT:
 249                                 return ParameterAttributes.Out;
 250                         case Modifier.PARAMS:
 251                                 return 0;
 252                         }
 253
 254                         return ParameterAttributes.None;
 255                 }
 256
 257                 public override AttributeTargets AttributeTargets {
 258                         get {
 259                                 return AttributeTargets.Parameter;
 260                         }
 261                 }
 262
 263                 /// <summary>
 264                 ///   Returns the signature for this parameter evaluating it on the
 265                 ///   @tc context
 266                 /// </summary>
 267                 public string GetSignature (EmitContext ec, Location loc)
 268                 {
 269                         if (parameter_type == null){
 270                                 if (!Resolve (ec, loc))
 271                                         return null;
 272                         }
 273
 274                         return ExternalType ().FullName;
 275                 }
 276
 277                 public string GetSignatureForError ()
 278                 {
 279                         string typeName;
 280                         if (parameter_type != null)
 281                                 typeName = TypeManager.CSharpName (parameter_type);
 282                         else if (TypeName.Type != null)
 283                                 typeName = TypeManager.CSharpName (TypeName.Type);
 284                         else
 285                                 typeName = TypeName.ToString ();
 286
 287                         switch (ModFlags & unchecked (~Modifier.ISBYREF)) {
 288                                 case Modifier.OUT:
 289                                         return "out " + typeName;
 290                                 case Modifier.PARAMS:
 291                                         return "params " + typeName;
 292                                 case Modifier.REF:
 293                                         return "ref " + typeName;
 294                         }
 295                         return typeName;
 296                 }
 297
 298                 public void DefineParameter (EmitContext ec, MethodBuilder mb, ConstructorBuilder cb, int index, Location loc)
 299                 {
 300                         ParameterAttributes par_attr = Attributes;
 301
 302                         if (mb == null)
 303                                 builder = cb.DefineParameter (index, par_attr, Name);
 304                         else
 305                                 builder = mb.DefineParameter (index, par_attr, Name);
 306
 307                         if (OptAttributes != null) {
 308                                 OptAttributes.Emit (ec, this);
 309
 310                                 if (par_attr == ParameterAttributes.Out){
 311                                         if (OptAttributes.Contains (TypeManager.in_attribute_type, ec))
 312                                                 Report.Error (36, loc,  "Can not use [In] attribute on out parameter");
 313                                 }
 314                         }
 315                 }
 316
 317                 public override string[] ValidAttributeTargets {
 318                         get {
 319                                 return attribute_targets;
 320                         }
 321                 }
 322         }
 323
 324         /// <summary>
 325         ///   Represents the methods parameters
 326         /// </summary>
 327         public class Parameters {
 328                 public Parameter [] FixedParameters;
 329                 public readonly Parameter ArrayParameter;
 330                 public readonly bool HasArglist;
 331                 string signature;
 332                 Type [] types;
 333                 Location loc;
 334
 335                 static Parameters empty_parameters;
 336
 337                 public Parameters (Parameter [] fixed_parameters, Parameter array_parameter, Location l)
 338                 {
 339                         FixedParameters = fixed_parameters;
 340                         ArrayParameter  = array_parameter;
 341                         loc = l;
 342                 }
 343
 344                 public Parameters (Parameter [] fixed_parameters, bool has_arglist, Location l)
 345                 {
 346                         FixedParameters = fixed_parameters;
 347                         HasArglist = has_arglist;
 348                         loc = l;
 349                 }
 350
 351                 /// <summary>
 352                 ///   This is used to reuse a set of empty parameters, because they
 353                 ///   are common
 354                 /// </summary>
 355                 public static Parameters EmptyReadOnlyParameters {
 356                         get {
 357                                 if (empty_parameters == null)
 358                                         empty_parameters = new Parameters (null, null, Location.Null);
 359
 360                                 return empty_parameters;
 361                         }
 362                 }
 363
 364                 public bool Empty {
 365                         get {
 366                                 return (FixedParameters == null) && (ArrayParameter == null);
 367                         }
 368                 }
 369
 370                 public void ComputeSignature (EmitContext ec)
 371                 {
 372                         signature = "";
 373                         if (FixedParameters != null){
 374                                 for (int i = 0; i < FixedParameters.Length; i++){
 375                                         Parameter par = FixedParameters [i];
 376
 377                                         signature += par.GetSignature (ec, loc);
 378                                 }
 379                         }
 380                         //
 381                         // Note: as per the spec, the `params' arguments (ArrayParameter)
 382                         // are not used in the signature computation for a method
 383                         //
 384                 }
 385
 386                 void Error_DuplicateParameterName (string name)
 387                 {
 388                         Report.Error (
 389                                 100, loc, "The parameter name `" + name + "' is a duplicate");
 390                 }
 391
 392                 public bool VerifyArgs ()
 393                 {
 394                         int count;
 395                         int i, j;
 396
 397                         if (FixedParameters == null)
 398                                 return true;
 399
 400                         count = FixedParameters.Length;
 401                         string array_par_name = ArrayParameter != null ? ArrayParameter.Name : null;
 402
 403                         for (i = 0; i < count; i++){
 404                                 string base_name = FixedParameters [i].Name;
 405                                 for (j = i + 1; j < count; j++){
 406                                         if (base_name != FixedParameters [j].Name)
 407                                                 continue;
 408                                         Error_DuplicateParameterName (base_name);
 409                                         return false;
 410                                 }
 411
 412                                 if (base_name == array_par_name){
 413                                         Error_DuplicateParameterName (base_name);
 414                                         return false;
 415                                 }
 416                         }
 417                         return true;
 418                 }
 419
 420                 /// <summary>
 421                 ///    Returns the signature of the Parameters evaluated in
 422                 ///    the @ec EmitContext
 423                 /// </summary>
 424                 public string GetSignature (EmitContext ec)
 425                 {
 426                         if (signature == null){
 427                                 VerifyArgs ();
 428                                 ComputeSignature (ec);
 429                         }
 430
 431                         return signature;
 432                 }
 433
 434                 /// <summary>
 435                 ///    Returns the paramenter information based on the name
 436                 /// </summary>
 437                 public Parameter GetParameterByName (string name, out int idx)
 438                 {
 439                         idx = 0;
 440                         int i = 0;
 441
 442                         if (FixedParameters != null){
 443                                 foreach (Parameter par in FixedParameters){
 444                                         if (par.Name == name){
 445                                                 idx = i;
 446                                                 return par;
 447                                         }
 448                                         i++;
 449                                 }
 450                         }
 451
 452                         if (ArrayParameter != null){
 453                                 if (name == ArrayParameter.Name){
 454                                         idx = i;
 455                                         return ArrayParameter;
 456                                 }
 457                         }
 458
 459                         return null;
 460                 }
 461
 462                 public Parameter GetParameterByName (string name)
 463                 {
 464                         int idx;
 465
 466                         return GetParameterByName (name, out idx);
 467                 }
 468
 469                 bool ComputeParameterTypes (EmitContext ec)
 470                 {
 471                         int extra = (ArrayParameter != null) ? 1 : 0;
 472                         int i = 0;
 473                         int pc;
 474
 475                         if (FixedParameters == null)
 476                                 pc = extra;
 477                         else
 478                                 pc = extra + FixedParameters.Length;
 479
 480                         types = new Type [pc];
 481
 482                         if (!VerifyArgs ()){
 483                                 FixedParameters = null;
 484                                 return false;
 485                         }
 486
 487                         bool failed = false;
 488                         if (FixedParameters != null){
 489                                 foreach (Parameter p in FixedParameters){
 490                                         Type t = null;
 491
 492                                         if (p.Resolve (ec, loc))
 493                                                 t = p.ExternalType ();
 494                                         else
 495                                                 failed = true;
 496
 497                                         types [i] = t;
 498                                         i++;
 499                                 }
 500                         }
 501
 502                         if (extra > 0){
 503                                 if (ArrayParameter.Resolve (ec, loc))
 504                                         types [i] = ArrayParameter.ExternalType ();
 505                                 else
 506                                         failed = true;
 507                         }
 508
 509                         if (failed){
 510                                 types = null;
 511                                 return false;
 512                         }
 513
 514                         return true;
 515                 }
 516
 517                 //
 518                 // This variant is used by Delegates, because they need to
 519                 // resolve/define names, instead of the plain LookupType
 520                 //
 521                 public bool ComputeAndDefineParameterTypes (EmitContext ec)
 522                 {
 523                         bool old_type_resolving = ec.ResolvingTypeTree;
 524                         ec.ResolvingTypeTree = true;
 525                         bool retval = ComputeParameterTypes (ec);
 526                         ec.ResolvingTypeTree = old_type_resolving;
 527                         return retval;
 528                 }
 529
 530                 /// <summary>
 531                 ///   Returns the argument types as an array
 532                 /// </summary>
 533                 static Type [] no_types = new Type [0];
 534
 535                 public Type [] GetParameterInfo (EmitContext ec)
 536                 {
 537                         if (types != null)
 538                                 return types;
 539
 540                         if (FixedParameters == null && ArrayParameter == null)
 541                                 return no_types;
 542
 543                         if (ComputeParameterTypes (ec) == false){
 544                                 types = null;
 545                                 return null;
 546                         }
 547
 548                         return types;
 549                 }
 550
 551                 /// <summary>
 552                 ///   Returns the type of a given parameter, and stores in the `is_out'
 553                 ///   boolean whether this is an out or ref parameter.
 554                 ///
 555                 ///   Note that the returned type will not contain any dereference in this
 556                 ///   case (ie, you get "int" for a ref int instead of "int&"
 557                 /// </summary>
 558                 public Type GetParameterInfo (EmitContext ec, int idx, out Parameter.Modifier mod)
 559                 {
 560                         mod = Parameter.Modifier.NONE;
 561
 562                         if (!VerifyArgs ()){
 563                                 FixedParameters = null;
 564                                 return null;
 565                         }
 566
 567                         if (FixedParameters == null && ArrayParameter == null)
 568                                 return null;
 569
 570                         if (types == null)
 571                                 if (ComputeParameterTypes (ec) == false)
 572                                         return null;
 573
 574                         //
 575                         // If this is a request for the variable lenght arg.
 576                         //
 577                         int array_idx = (FixedParameters != null ? FixedParameters.Length : 0);
 578                         if (idx == array_idx)
 579                                 return types [idx];
 580
 581                         //
 582                         // Otherwise, it is a fixed parameter
 583                         //
 584                         Parameter p = FixedParameters [idx];
 585                         mod = p.ModFlags;
 586
 587                         if ((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) != 0)
 588                                 mod |= Parameter.Modifier.ISBYREF;
 589
 590                         return p.ParameterType;
 591                 }
 592
 593                 public CallingConventions GetCallingConvention ()
 594                 {
 595                         if (HasArglist)
 596                                 return CallingConventions.VarArgs;
 597                         else
 598                         return CallingConventions.Standard;
 599                 }
 600
 601                 //
 602                 // The method's attributes are passed in because we need to extract
 603                 // the "return:" attribute from there to apply on the return type
 604                 //
 605                 public void LabelParameters (EmitContext ec,
 606                         MethodBase builder,
 607                         Location loc) {
 608                         //
 609                         // Define each type attribute (in/out/ref) and
 610                         // the argument names.
 611                         //
 612                         int i = 0;
 613
 614                         MethodBuilder mb = builder as MethodBuilder;
 615                         ConstructorBuilder cb = builder as ConstructorBuilder;
 616
 617                         if (FixedParameters != null) {
 618                                 for (i = 0; i < FixedParameters.Length; i++) {
 619                                         FixedParameters [i].DefineParameter (ec, mb, cb, i + 1, loc);
 620                                 }
 621                         }
 622
 623                         if (ArrayParameter != null){
 624                                 ParameterBuilder pb;
 625                                 Parameter array_param = ArrayParameter;
 626
 627                                 if (mb == null)
 628                                         pb = cb.DefineParameter (
 629                                                 i + 1, array_param.Attributes,
 630                                                 array_param.Name);
 631                                 else
 632                                         pb = mb.DefineParameter (
 633                                                 i + 1, array_param.Attributes,
 634                                                 array_param.Name);
 635
 636                                 CustomAttributeBuilder a = new CustomAttributeBuilder (
 637                                         TypeManager.cons_param_array_attribute, new object [0]);
 638
 639                                 pb.SetCustomAttribute (a);
 640                         }
 641                 }
 642         }
 643 }