mcs/mbas/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
  20         /// <summary>
  21         ///   Represents a single method parameter
  22         /// </summary>
  23         public class Parameter {
  24                 [Flags]
  25                 public enum Modifier : byte {
  26                         NONE    = 0,
  27                         VAL     = 0,
  28                         REF     = 1,
  29                         OUT     = 2,
  30                         PARAMS  = 4,
  31                         // This is a flag which says that it's either REF or OUT.
  32                         ISBYREF = 8,
  33                         OPTIONAL = 16
  34                 }
  35
  36                 public readonly Expression TypeName;
  37                 public readonly Modifier ModFlags;
  38                 public Attributes OptAttributes;
  39                 public readonly string Name;
  40                 public Type parameter_type;
  41                 public readonly Expression ParameterInitializer;
  42                 public readonly bool IsOptional;
  43
  44                 public Parameter (Expression type, string name, Modifier mod, Attributes attrs)
  45                 {
  46                         Name = name;
  47                         ModFlags = mod;
  48                         TypeName = type;
  49                         OptAttributes = attrs;
  50                         ParameterInitializer = null;
  51                         IsOptional = false;
  52                 }
  53
  54                 public Parameter (Expression type, string name, Modifier mod, Attributes attrs, Expression pi)
  55                 {
  56                         Name = name;
  57                         ModFlags = mod;
  58                         TypeName = type;
  59                         OptAttributes = attrs;
  60                         ParameterInitializer = pi;
  61                         IsOptional = false;
  62                 }
  63
  64                 public Parameter (Expression type, string name, Modifier mod, Attributes attrs, Expression pi, bool opt)
  65                 {
  66                         Name = name;
  67                         ModFlags = mod;
  68                         TypeName = type;
  69                         OptAttributes = attrs;
  70                         ParameterInitializer = pi;
  71                         IsOptional = opt;
  72                 }
  73
  74
  75                 // <summary>
  76                 //   Resolve is used in method definitions
  77                 // </summary>
  78                 public bool Resolve (DeclSpace ds, Location l)
  79                 {
  80                         parameter_type = ds.ResolveType (TypeName, false, l);
  81
  82                         if (parameter_type == TypeManager.void_type){
  83                                 Report.Error (1536, l, "`void' parameter is not permitted");
  84                                 return false;
  85                         }
  86
  87                         return parameter_type != null;
  88                 }
  89
  90                 public Type ExternalType (DeclSpace ds, Location l)
  91                 {
  92                         if ((ModFlags & Parameter.Modifier.ISBYREF) != 0){
  93                                 string n = parameter_type.FullName + "&";
  94
  95                                 Type t = RootContext.LookupType (ds, n, false, l);
  96
  97                                 return t;
  98                         }
  99
 100                         return parameter_type;
 101                 }
 102
 103                 public Type ParameterType {
 104                         get {
 105                                 return parameter_type;
 106                         }
 107                 }
 108
 109                 public ParameterAttributes Attributes {
 110                         get {
 111                                 int flags = ((int) ModFlags) & ~((int) Parameter.Modifier.ISBYREF);
 112                                 switch ((Modifier) flags) {
 113                                 case Modifier.NONE:
 114                                         return ParameterAttributes.None;
 115                                 case Modifier.REF:
 116                                         return ParameterAttributes.None;
 117                                 case Modifier.OUT:
 118                                         return ParameterAttributes.Out;
 119                                 case Modifier.PARAMS:
 120                                         return 0;
 121                                 }
 122
 123                                 return ParameterAttributes.None;
 124                         }
 125                 }
 126
 127                 /// <summary>
 128                 ///   Returns the signature for this parameter evaluating it on the
 129                 ///   @tc context
 130                 /// </summary>
 131                 public string GetSignature (DeclSpace ds, Location loc)
 132                 {
 133                         if (parameter_type == null){
 134                                 if (!Resolve (ds, loc))
 135                                         return null;
 136                         }
 137
 138                         return ExternalType (ds, loc).FullName;
 139                 }
 140         }
 141
 142         /// <summary>
 143         ///   Represents the methods parameters
 144         /// </summary>
 145         public class Parameters {
 146                 public Parameter [] FixedParameters;
 147                 public readonly Parameter ArrayParameter;
 148                 string signature;
 149                 Type [] types;
 150                 Location loc;
 151
 152                 static Parameters empty_parameters;
 153
 154                 public Parameters (Parameter [] fixed_parameters, Parameter array_parameter, Location l)
 155                 {
 156                         FixedParameters = fixed_parameters;
 157                         ArrayParameter  = array_parameter;
 158                         loc = l;
 159                 }
 160
 161                 /// <summary>
 162                 ///   This is used to reuse a set of empty parameters, because they
 163                 ///   are common
 164                 /// </summary>
 165                 public static Parameters EmptyReadOnlyParameters {
 166                         get {
 167                                 if (empty_parameters == null)
 168                                         empty_parameters = new Parameters (null, null, Location.Null);
 169
 170                                 return empty_parameters;
 171                         }
 172                 }
 173
 174                 public bool HasOptional()
 175                 {
 176                         bool res = false;
 177
 178                         foreach (Parameter p in FixedParameters)
 179                         {
 180                                 if (p.IsOptional)
 181                                 {
 182                                         res = true;
 183                                         break;
 184                                 }
 185                         }
 186                         return (res);
 187                 }
 188
 189                 /// <summary>
 190                 ///   Returns the number of standard (i.e. non-optional) parameters
 191                 /// </summary>
 192                 public int CountStandardParams()
 193                 {
 194                         int res = 0;
 195
 196                         foreach (Parameter p in FixedParameters) {
 197                                 if (!p.IsOptional)
 198                                         res++;
 199                         }
 200                         return (res);
 201                 }
 202
 203                 /// <summary>
 204                 ///   Returns the number of optional parameters
 205                 /// </summary>
 206                 public int CountOptionalParams()
 207                 {
 208                         int res = 0;
 209
 210                         foreach (Parameter p in FixedParameters) {
 211                                 if (p.IsOptional)
 212                                         res++;
 213                         }
 214                         return (res);
 215                 }
 216
 217                 public Expression GetDefaultValue (int i)
 218                 {
 219                         Parameter p = FixedParameters[i];
 220                         if (p.IsOptional)
 221                                 return p.ParameterInitializer;
 222                         else
 223                                 return null;
 224                 }
 225
 226                 public void AppendParameter (Parameter p)
 227                 {
 228                         if (FixedParameters != null)
 229                         {
 230                                 Parameter [] pa = new Parameter [FixedParameters.Length+1];
 231                                 FixedParameters.CopyTo (pa, 0);
 232                                 pa[FixedParameters.Length] = p;
 233                                 FixedParameters = pa;
 234                         }
 235                         else
 236                         {
 237                                 FixedParameters = new Parameter [1];
 238                                 FixedParameters[0] = p;
 239                         }
 240                 }
 241
 242                 public void PrependParameter (Parameter p)
 243                 {
 244                         Parameter [] pa = new Parameter [FixedParameters.Length+1];
 245                         FixedParameters.CopyTo (pa, 1);
 246                         pa[0] = p;
 247                         FixedParameters = pa;
 248                 }
 249
 250                 public Parameters Copy (Location l)
 251                 {
 252                         Parameters p = new Parameters (null, null, l);
 253                         p.FixedParameters = new Parameter[this.FixedParameters.Length];
 254                         this.FixedParameters.CopyTo (p.FixedParameters, 0);
 255
 256                         return (p);
 257
 258                 }
 259
 260                 public bool Empty {
 261                         get {
 262                                 return (FixedParameters == null) && (ArrayParameter == null);
 263                         }
 264                 }
 265
 266                 public void ComputeSignature (DeclSpace ds)
 267                 {
 268                         signature = "";
 269                         if (FixedParameters != null){
 270                                 for (int i = 0; i < FixedParameters.Length; i++){
 271                                         Parameter par = FixedParameters [i];
 272
 273                                         signature += par.GetSignature (ds, loc);
 274                                 }
 275                         }
 276                         //
 277                         // Note: as per the spec, the `params' arguments (ArrayParameter)
 278                         // are not used in the signature computation for a method
 279                         //
 280                 }
 281
 282                 static void Error_DuplicateParameterName (string name)
 283                 {
 284                         Report.Error (
 285                                 100, "The parameter name `" + name + "' is a duplicate");
 286                 }
 287
 288                 public bool VerifyArgs ()
 289                 {
 290                         int count;
 291                         int i, j;
 292
 293                         if (FixedParameters == null)
 294                                 return true;
 295
 296                         count = FixedParameters.Length;
 297                         string array_par_name = ArrayParameter != null ? ArrayParameter.Name : null;
 298                         for (i = 0; i < count; i++){
 299                                 string base_name = FixedParameters [i].Name;
 300
 301                                 for (j = i + 1; j < count; j++){
 302                                         if (base_name != FixedParameters [j].Name)
 303                                                 continue;
 304                                         Error_DuplicateParameterName (base_name);
 305                                         return false;
 306                                 }
 307
 308                                 if (base_name == array_par_name){
 309                                         Error_DuplicateParameterName (base_name);
 310                                         return false;
 311                                 }
 312                         }
 313                         return true;
 314                 }
 315
 316                 /// <summary>
 317                 ///    Returns the signature of the Parameters evaluated in
 318                 ///    the @tc environment
 319                 /// </summary>
 320                 public string GetSignature (DeclSpace ds)
 321                 {
 322                         if (signature == null){
 323                                 VerifyArgs ();
 324                                 ComputeSignature (ds);
 325                         }
 326
 327                         return signature;
 328                 }
 329
 330                 /// <summary>
 331                 ///    Returns the paramenter information based on the name
 332                 /// </summary>
 333                 public Parameter GetParameterByName (string name, out int idx)
 334                 {
 335                         idx = 0;
 336                         int i = 0;
 337
 338                         if (FixedParameters != null){
 339                                 foreach (Parameter par in FixedParameters){
 340                                         if (par.Name == name){
 341                                                 idx = i;
 342                                                 return par;
 343                                         }
 344                                         i++;
 345                                 }
 346                         }
 347
 348                         if (ArrayParameter != null){
 349                                 if (name == ArrayParameter.Name){
 350                                         idx = i;
 351                                         return ArrayParameter;
 352                                 }
 353                         }
 354
 355                         return null;
 356                 }
 357
 358                 bool ComputeParameterTypes (DeclSpace ds)
 359                 {
 360                         int extra = (ArrayParameter != null) ? 1 : 0;
 361                         int i = 0;
 362                         int pc;
 363
 364                         if (FixedParameters == null)
 365                                 pc = extra;
 366                         else
 367                                 pc = extra + FixedParameters.Length;
 368
 369                         types = new Type [pc];
 370
 371                         if (!VerifyArgs ()){
 372                                 FixedParameters = null;
 373                                 return false;
 374                         }
 375
 376                         bool failed = false;
 377                         if (FixedParameters != null){
 378                                 foreach (Parameter p in FixedParameters){
 379                                         Type t = null;
 380
 381                                         if (p.Resolve (ds, loc))
 382                                                 t = p.ExternalType (ds, loc);
 383                                         else
 384                                                 failed = true;
 385
 386                                         types [i] = t;
 387                                         i++;
 388                                 }
 389                         }
 390
 391                         if (extra > 0){
 392                                 if (ArrayParameter.Resolve (ds, loc))
 393                                         types [i] = ArrayParameter.ExternalType (ds, loc);
 394                                 else
 395                                         failed = true;
 396                         }
 397
 398                         if (failed){
 399                                 types = null;
 400                                 return false;
 401                         }
 402
 403                         return true;
 404                 }
 405
 406                 //
 407                 // This variant is used by Delegates, because they need to
 408                 // resolve/define names, instead of the plain LookupType
 409                 //
 410                 public bool ComputeAndDefineParameterTypes (DeclSpace ds)
 411                 {
 412                         int extra = (ArrayParameter != null) ? 1 : 0;
 413                         int i = 0;
 414                         int pc;
 415
 416                         if (FixedParameters == null)
 417                                 pc = extra;
 418                         else
 419                                 pc = extra + FixedParameters.Length;
 420
 421                         types = new Type [pc];
 422
 423                         if (!VerifyArgs ()){
 424                                 FixedParameters = null;
 425                                 return false;
 426                         }
 427
 428                         bool ok_flag = true;
 429
 430                         if (FixedParameters != null){
 431                                 foreach (Parameter p in FixedParameters){
 432                                         Type t = null;
 433
 434                                         if (p.Resolve (ds, loc))
 435                                                 t = p.ExternalType (ds, loc);
 436                                         else
 437                                                 ok_flag = false;
 438
 439                                         types [i] = t;
 440                                         i++;
 441                                 }
 442                         }
 443
 444                         if (extra > 0){
 445                                 if (ArrayParameter.Resolve (ds, loc))
 446                                         types [i] = ArrayParameter.ExternalType (ds, loc);
 447                                 else
 448                                         ok_flag = false;
 449                         }
 450
 451                         //
 452                         // invalidate the cached types
 453                         //
 454                         if (!ok_flag){
 455                                 types = null;
 456                         }
 457
 458                         return ok_flag;
 459                 }
 460
 461                 /// <summary>
 462                 ///   Returns the argument types as an array
 463                 /// </summary>
 464                 static Type [] no_types = new Type [0];
 465
 466                 public Type [] GetParameterInfo (DeclSpace ds)
 467                 {
 468                         if (types != null)
 469                                 return types;
 470
 471                         if (FixedParameters == null && ArrayParameter == null)
 472                                 return no_types;
 473
 474                         if (ComputeParameterTypes (ds) == false){
 475                                 types = null;
 476                                 return null;
 477                         }
 478
 479                         return types;
 480                 }
 481
 482                 /// <summary>
 483                 ///   Returns the type of a given parameter, and stores in the `is_out'
 484                 ///   boolean whether this is an out or ref parameter.
 485                 ///
 486                 ///   Note that the returned type will not contain any dereference in this
 487                 ///   case (ie, you get "int" for a ref int instead of "int&"
 488                 /// </summary>
 489                 public Type GetParameterInfo (DeclSpace ds, int idx, out Parameter.Modifier mod)
 490                 {
 491                         mod = Parameter.Modifier.NONE;
 492
 493                         if (!VerifyArgs ()){
 494                                 FixedParameters = null;
 495                                 return null;
 496                         }
 497
 498                         if (FixedParameters == null && ArrayParameter == null)
 499                                 return null;
 500
 501                         if (types == null)
 502                                 if (ComputeParameterTypes (ds) == false)
 503                                         return null;
 504
 505                         //
 506                         // If this is a request for the variable lenght arg.
 507                         //
 508                         int array_idx = (FixedParameters != null ? FixedParameters.Length : 0);
 509                         if (idx == array_idx)
 510                                 return types [idx];
 511
 512                         //
 513                         // Otherwise, it is a fixed parameter
 514                         //
 515                         Parameter p = FixedParameters [idx];
 516                         mod = p.ModFlags;
 517
 518                         if ((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) != 0)
 519                                 mod |= Parameter.Modifier.ISBYREF;
 520
 521                         return p.ParameterType;
 522                 }
 523
 524                 public CallingConventions GetCallingConvention ()
 525                 {
 526                         // For now this is the only correc thing to do
 527                         return CallingConventions.Standard;
 528                 }
 529         }
 530 }
 531
 532
 533