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