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