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
  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                         return parameter_type != null;
  55                 }
  56
  57                 // <summary>
  58                 //   ResolveAndDefine is used by delegate declarations, because
  59                 //   they happen during the initial tree resolution process
  60                 // </summary>
  61                 public bool ResolveAndDefine (DeclSpace ds)
  62                 {
  63                         // FIXME: Should use something else instead of Location.Null
  64                         parameter_type = ds.ResolveType (TypeName, true, Location.Null);
  65                         return parameter_type != null;
  66                 }
  67
  68                 public Type ExternalType (DeclSpace ds, Location l)
  69                 {
  70                         if ((ModFlags & Parameter.Modifier.ISBYREF) != 0){
  71                                 string n = parameter_type.FullName + "&";
  72
  73                                 Type t = RootContext.LookupType (ds, n, false, l);
  74
  75                                 return t;
  76                         }
  77
  78                         return parameter_type;
  79                 }
  80
  81                 public Type ParameterType {
  82                         get {
  83                                 return parameter_type;
  84                         }
  85                 }
  86
  87                 public ParameterAttributes Attributes {
  88                         get {
  89                                 switch (ModFlags){
  90                                 case Modifier.NONE:
  91                                         return ParameterAttributes.None;
  92                                 case Modifier.REF:
  93                                         return ParameterAttributes.None;
  94                                 case Modifier.OUT:
  95                                         return ParameterAttributes.Out;
  96                                 case Modifier.PARAMS:
  97                                         return 0;
  98                                 }
  99
 100                                 return ParameterAttributes.None;
 101                         }
 102                 }
 103
 104                 /// <summary>
 105                 ///   Returns the signature for this parameter evaluating it on the
 106                 ///   @tc context
 107                 /// </summary>
 108                 public string GetSignature (DeclSpace ds, Location loc)
 109                 {
 110                         if (parameter_type == null){
 111                                 if (!Resolve (ds, loc))
 112                                         return null;
 113                         }
 114
 115                         return ExternalType (ds, loc).FullName;
 116                 }
 117         }
 118
 119         /// <summary>
 120         ///   Represents the methods parameters
 121         /// </summary>
 122         public class Parameters {
 123                 public Parameter [] FixedParameters;
 124                 public readonly Parameter ArrayParameter;
 125                 string signature;
 126                 Type [] types;
 127                 Location loc;
 128
 129                 static Parameters empty_parameters;
 130
 131                 public Parameters (Parameter [] fixed_parameters, Parameter array_parameter, Location l)
 132                 {
 133                         FixedParameters = fixed_parameters;
 134                         ArrayParameter  = array_parameter;
 135                         loc = l;
 136                 }
 137
 138                 /// <summary>
 139                 ///   This is used to reuse a set of empty parameters, because they
 140                 ///   are common
 141                 /// </summary>
 142                 public static Parameters GetEmptyReadOnlyParameters ()
 143                 {
 144                         if (empty_parameters == null)
 145                                 empty_parameters = new Parameters (null, null, Location.Null);
 146
 147                         return empty_parameters;
 148                 }
 149
 150                 public bool Empty {
 151                         get {
 152                                 return (FixedParameters == null) && (ArrayParameter == null);
 153                         }
 154                 }
 155
 156                 public void ComputeSignature (DeclSpace ds)
 157                 {
 158                         signature = "";
 159                         if (FixedParameters != null){
 160                                 for (int i = 0; i < FixedParameters.Length; i++){
 161                                         Parameter par = FixedParameters [i];
 162
 163                                         signature += par.GetSignature (ds, loc);
 164                                 }
 165                         }
 166                         //
 167                         // Note: as per the spec, the `params' arguments (ArrayParameter)
 168                         // are not used in the signature computation for a method
 169                         //
 170                 }
 171
 172                 static void error100 (string name)
 173                 {
 174                         Report.Error (
 175                                 100, "The parameter name `" + name + "' is a duplicate");
 176                 }
 177
 178                 public bool VerifyArgs ()
 179                 {
 180                         int count;
 181                         int i, j;
 182
 183                         if (FixedParameters == null)
 184                                 return true;
 185
 186                         count = FixedParameters.Length;
 187                         string array_par_name = ArrayParameter != null ? ArrayParameter.Name : null;
 188                         for (i = 0; i < count; i++){
 189                                 string base_name = FixedParameters [i].Name;
 190
 191                                 for (j = i + 1; j < count; j++){
 192                                         if (base_name != FixedParameters [j].Name)
 193                                                 continue;
 194                                         error100 (base_name);
 195                                         return false;
 196                                 }
 197
 198                                 if (base_name == array_par_name){
 199                                         error100 (base_name);
 200                                         return false;
 201                                 }
 202                         }
 203                         return true;
 204                 }
 205
 206                 /// <summary>
 207                 ///    Returns the signature of the Parameters evaluated in
 208                 ///    the @tc environment
 209                 /// </summary>
 210                 public string GetSignature (DeclSpace ds)
 211                 {
 212                         if (signature == null){
 213                                 VerifyArgs ();
 214                                 ComputeSignature (ds);
 215                         }
 216
 217                         return signature;
 218                 }
 219
 220                 /// <summary>
 221                 ///    Returns the paramenter information based on the name
 222                 /// </summary>
 223                 public Parameter GetParameterByName (string name, out int idx)
 224                 {
 225                         idx = 0;
 226                         int i = 0;
 227
 228                         if (FixedParameters != null){
 229                                 foreach (Parameter par in FixedParameters){
 230                                         if (par.Name == name){
 231                                                 idx = i;
 232                                                 return par;
 233                                         }
 234                                         i++;
 235                                 }
 236                         }
 237
 238                         if (ArrayParameter != null){
 239                                 if (name == ArrayParameter.Name){
 240                                         idx = i;
 241                                         return ArrayParameter;
 242                                 }
 243                         }
 244
 245                         return null;
 246                 }
 247
 248                 bool ComputeParameterTypes (DeclSpace ds)
 249                 {
 250                         int extra = (ArrayParameter != null) ? 1 : 0;
 251                         int i = 0;
 252                         int pc;
 253
 254                         if (FixedParameters == null)
 255                                 pc = extra;
 256                         else
 257                                 pc = extra + FixedParameters.Length;
 258
 259                         types = new Type [pc];
 260
 261                         if (!VerifyArgs ()){
 262                                 FixedParameters = null;
 263                                 return false;
 264                         }
 265
 266                         bool failed = false;
 267                         if (FixedParameters != null){
 268                                 foreach (Parameter p in FixedParameters){
 269                                         Type t = null;
 270
 271                                         if (p.Resolve (ds, loc))
 272                                                 t = p.ExternalType (ds, loc);
 273                                         else
 274                                                 failed = true;
 275
 276                                         types [i] = t;
 277                                         i++;
 278                                 }
 279                         }
 280
 281                         if (failed)
 282                                 types = null;
 283
 284                         if (extra > 0){
 285                                 if (ArrayParameter.Resolve (ds, loc))
 286                                         types [i] = ArrayParameter.ExternalType (ds, loc);
 287                                 else
 288                                         return false;
 289                         }
 290
 291                         return true;
 292                 }
 293
 294                 //
 295                 // This variant is used by Delegates, because they need to
 296                 // resolve/define names, instead of the plain LookupType
 297                 //
 298                 public bool ComputeAndDefineParameterTypes (DeclSpace ds)
 299                 {
 300                         int extra = (ArrayParameter != null) ? 1 : 0;
 301                         int i = 0;
 302                         int pc;
 303
 304                         if (FixedParameters == null)
 305                                 pc = extra;
 306                         else
 307                                 pc = extra + FixedParameters.Length;
 308
 309                         types = new Type [pc];
 310
 311                         if (!VerifyArgs ()){
 312                                 FixedParameters = null;
 313                                 return false;
 314                         }
 315
 316                         bool ok_flag = true;
 317
 318                         if (FixedParameters != null){
 319                                 foreach (Parameter p in FixedParameters){
 320                                         Type t = null;
 321
 322                                         if (p.ResolveAndDefine (ds))
 323                                                 t = p.ExternalType (ds, loc);
 324                                         else
 325                                                 ok_flag = false;
 326
 327                                         types [i] = t;
 328                                         i++;
 329                                 }
 330                         }
 331
 332                         if (extra > 0){
 333                                 if (ArrayParameter.ResolveAndDefine (ds))
 334                                         types [i] = ArrayParameter.ExternalType (ds, loc);
 335                                 else
 336                                         ok_flag = false;
 337                         }
 338
 339                         //
 340                         // invalidate the cached types
 341                         //
 342                         if (!ok_flag){
 343                                 types = null;
 344                         }
 345
 346                         return ok_flag;
 347                 }
 348
 349                 /// <summary>
 350                 ///   Returns the argument types as an array
 351                 /// </summary>
 352                 static Type [] no_types = new Type [0];
 353
 354                 public Type [] GetParameterInfo (DeclSpace ds)
 355                 {
 356                         if (types != null)
 357                                 return types;
 358
 359                         if (FixedParameters == null && ArrayParameter == null)
 360                                 return no_types;
 361
 362                         if (ComputeParameterTypes (ds) == false){
 363                                 types = null;
 364                                 return null;
 365                         }
 366
 367                         return types;
 368                 }
 369
 370                 /// <summary>
 371                 ///   Returns the type of a given parameter, and stores in the `is_out'
 372                 ///   boolean whether this is an out or ref parameter.
 373                 ///
 374                 ///   Note that the returned type will not contain any dereference in this
 375                 ///   case (ie, you get "int" for a ref int instead of "int&"
 376                 /// </summary>
 377                 public Type GetParameterInfo (DeclSpace ds, int idx, out Parameter.Modifier mod)
 378                 {
 379                         mod = Parameter.Modifier.NONE;
 380
 381                         if (!VerifyArgs ()){
 382                                 FixedParameters = null;
 383                                 return null;
 384                         }
 385
 386                         if (FixedParameters == null && ArrayParameter == null)
 387                                 return null;
 388
 389                         if (types == null)
 390                                 if (ComputeParameterTypes (ds) == false)
 391                                         return null;
 392
 393                         //
 394                         // If this is a request for the variable lenght arg.
 395                         //
 396                         int array_idx = (FixedParameters != null ? FixedParameters.Length : 0);
 397                         if (idx == array_idx)
 398                                 return types [idx];
 399
 400                         //
 401                         // Otherwise, it is a fixed parameter
 402                         //
 403                         Parameter p = FixedParameters [idx];
 404                         mod = p.ModFlags;
 405
 406                         if ((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) != 0)
 407                                 mod |= Parameter.Modifier.ISBYREF;
 408
 409                         return p.ParameterType;
 410                 }
 411
 412                 public CallingConventions GetCallingConvention ()
 413                 {
 414                         // For now this is the only correc thing to do
 415                         return CallingConventions.Standard;
 416                 }
 417         }
 418 }
 419
 420
 421