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                 }
  31
  32                 public readonly string   TypeName;
  33                 public readonly string   Name;
  34                 public readonly Modifier ModFlags;
  35                 public Attributes OptAttributes;
  36                 public Type ParameterType;
  37
  38                 public Parameter (string type, string name, Modifier mod, Attributes attrs)
  39                 {
  40                         Name = name;
  41                         ModFlags = mod;
  42                         TypeName = type;
  43                         OptAttributes = attrs;
  44                 }
  45
  46                 // <summary>
  47                 //   Resolve is used in method definitions
  48                 // </summary>
  49                 public bool Resolve (DeclSpace ds, Location l)
  50                 {
  51                         ParameterType = RootContext.LookupType (ds, TypeName, false, l);
  52                         return ParameterType != null;
  53                 }
  54
  55                 // <summary>
  56                 //   ResolveAndDefine is used by delegate declarations, because
  57                 //   they happen during the initial tree resolution process
  58                 // </summary>
  59                 public bool ResolveAndDefine (DeclSpace ds)
  60                 {
  61                         ParameterType = ds.FindType (TypeName);
  62                         return ParameterType != null;
  63                 }
  64
  65                 public Type ExternalType (DeclSpace ds, Location l)
  66                 {
  67                         if ((ModFlags & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) != 0){
  68                                 string n = ParameterType.FullName + "&";
  69
  70                                 Type t = RootContext.LookupType (ds, n, false, l);
  71
  72                                 return t;
  73                         }
  74
  75                         return ParameterType;
  76                 }
  77
  78                 public ParameterAttributes Attributes {
  79                         get {
  80                                 switch (ModFlags){
  81                                 case Modifier.NONE:
  82                                         return ParameterAttributes.None;
  83                                 case Modifier.REF:
  84                                         return ParameterAttributes.None;
  85                                 case Modifier.OUT:
  86                                         return ParameterAttributes.Out;
  87                                 case Modifier.PARAMS:
  88                                         return 0;
  89                                 }
  90
  91                                 return ParameterAttributes.None;
  92                         }
  93                 }
  94
  95                 /// <summary>
  96                 ///   Returns the signature for this parameter evaluating it on the
  97                 ///   @tc context
  98                 /// </summary>
  99                 public string GetSignature (DeclSpace ds, Location loc)
 100                 {
 101                         if (ParameterType == null){
 102                                 if (!Resolve (ds, loc))
 103                                         return null;
 104                         }
 105
 106                         return ExternalType (ds, loc).FullName;
 107                 }
 108         }
 109
 110         /// <summary>
 111         ///   Represents the methods parameters
 112         /// </summary>
 113         public class Parameters {
 114                 public Parameter [] FixedParameters;
 115                 public readonly Parameter ArrayParameter;
 116                 string signature;
 117                 Type [] types;
 118                 Location loc;
 119
 120                 static Parameters empty_parameters;
 121
 122                 public Parameters (Parameter [] fixed_parameters, Parameter array_parameter, Location l)
 123                 {
 124                         FixedParameters = fixed_parameters;
 125                         ArrayParameter  = array_parameter;
 126                         loc = l;
 127                 }
 128
 129                 /// <summary>
 130                 ///   This is used to reuse a set of empty parameters, because they
 131                 ///   are common
 132                 /// </summary>
 133                 public static Parameters GetEmptyReadOnlyParameters ()
 134                 {
 135                         if (empty_parameters == null)
 136                                 empty_parameters = new Parameters (null, null, Location.Null);
 137
 138                         return empty_parameters;
 139                 }
 140
 141                 public bool Empty {
 142                         get {
 143                                 return (FixedParameters == null) && (ArrayParameter == null);
 144                         }
 145                 }
 146
 147                 public void ComputeSignature (DeclSpace ds)
 148                 {
 149                         signature = "";
 150                         if (FixedParameters != null){
 151                                 for (int i = 0; i < FixedParameters.Length; i++){
 152                                         Parameter par = FixedParameters [i];
 153
 154                                         signature += par.GetSignature (ds, loc);
 155                                 }
 156                         }
 157                         //
 158                         // Note: as per the spec, the `params' arguments (ArrayParameter)
 159                         // are not used in the signature computation for a method
 160                         //
 161                 }
 162
 163                 static void error100 (string name)
 164                 {
 165                         Report.Error (
 166                                 100, "The parameter name `" + name + "' is a duplicate");
 167                 }
 168
 169                 public bool VerifyArgs ()
 170                 {
 171                         int count;
 172                         int i, j;
 173
 174                         if (FixedParameters == null)
 175                                 return true;
 176
 177                         count = FixedParameters.Length;
 178                         string array_par_name = ArrayParameter != null ? ArrayParameter.Name : null;
 179                         for (i = 0; i < count; i++){
 180                                 string base_name = FixedParameters [i].Name;
 181
 182                                 for (j = i + 1; j < count; j++){
 183                                         if (base_name != FixedParameters [j].Name)
 184                                                 continue;
 185                                         error100 (base_name);
 186                                         return false;
 187                                 }
 188
 189                                 if (base_name == array_par_name){
 190                                         error100 (base_name);
 191                                         return false;
 192                                 }
 193                         }
 194                         return true;
 195                 }
 196
 197                 /// <summary>
 198                 ///    Returns the signature of the Parameters evaluated in
 199                 ///    the @tc environment
 200                 /// </summary>
 201                 public string GetSignature (DeclSpace ds)
 202                 {
 203                         if (signature == null){
 204                                 VerifyArgs ();
 205                                 ComputeSignature (ds);
 206                         }
 207
 208                         return signature;
 209                 }
 210
 211                 /// <summary>
 212                 ///    Returns the paramenter information based on the name
 213                 /// </summary>
 214                 public Parameter GetParameterByName (string name, out int idx)
 215                 {
 216                         idx = 0;
 217                         int i = 0;
 218
 219                         if (FixedParameters != null){
 220                                 foreach (Parameter par in FixedParameters){
 221                                         if (par.Name == name){
 222                                                 idx = i;
 223                                                 return par;
 224                                         }
 225                                         i++;
 226                                 }
 227                         }
 228
 229                         if (ArrayParameter != null){
 230                                 if (name == ArrayParameter.Name){
 231                                         idx = i;
 232                                         return ArrayParameter;
 233                                 }
 234                         }
 235
 236                         return null;
 237                 }
 238
 239                 bool ComputeParameterTypes (DeclSpace ds)
 240                 {
 241                         int extra = (ArrayParameter != null) ? 1 : 0;
 242                         int i = 0;
 243                         int pc;
 244
 245                         if (FixedParameters == null)
 246                                 pc = extra;
 247                         else
 248                                 pc = extra + FixedParameters.Length;
 249
 250                         types = new Type [pc];
 251
 252                         if (!VerifyArgs ()){
 253                                 FixedParameters = null;
 254                                 return false;
 255                         }
 256
 257                         bool failed = false;
 258                         if (FixedParameters != null){
 259                                 foreach (Parameter p in FixedParameters){
 260                                         Type t = null;
 261
 262                                         if (p.Resolve (ds, loc))
 263                                                 t = p.ExternalType (ds, loc);
 264                                         else
 265                                                 failed = true;
 266
 267                                         types [i] = t;
 268                                         i++;
 269                                 }
 270                         }
 271                         if (failed)
 272                                 return false;
 273
 274                         if (extra > 0){
 275                                 if (ArrayParameter.Resolve (ds, loc))
 276                                         types [i] = ArrayParameter.ExternalType (ds, loc);
 277                         }
 278
 279                         return true;
 280                 }
 281
 282                 //
 283                 // This variant is used by Delegates, because they need to
 284                 // resolve/define names, instead of the plain LookupType
 285                 //
 286                 public bool ComputeAndDefineParameterTypes (DeclSpace ds)
 287                 {
 288                         int extra = (ArrayParameter != null) ? 1 : 0;
 289                         int i = 0;
 290                         int pc;
 291
 292                         if (FixedParameters == null)
 293                                 pc = extra;
 294                         else
 295                                 pc = extra + FixedParameters.Length;
 296
 297                         types = new Type [pc];
 298
 299                         if (!VerifyArgs ()){
 300                                 FixedParameters = null;
 301                                 return false;
 302                         }
 303
 304                         if (FixedParameters != null){
 305                                 foreach (Parameter p in FixedParameters){
 306                                         Type t = null;
 307
 308                                         if (p.ResolveAndDefine (ds))
 309                                                 t = p.ExternalType (ds, loc);
 310
 311                                         types [i] = t;
 312                                         i++;
 313                                 }
 314                         }
 315
 316                         if (extra > 0){
 317                                 if (ArrayParameter.ResolveAndDefine (ds))
 318                                         types [i] = ArrayParameter.ExternalType (ds, loc);
 319                         }
 320
 321                         return true;
 322                 }
 323
 324                 /// <summary>
 325                 ///   Returns the argument types as an array
 326                 /// </summary>
 327                 static Type [] no_types = new Type [0];
 328
 329                 public Type [] GetParameterInfo (DeclSpace ds)
 330                 {
 331                         if (types != null)
 332                                 return types;
 333
 334                         if (FixedParameters == null && ArrayParameter == null)
 335                                 return no_types;
 336
 337                         if (ComputeParameterTypes (ds) == false)
 338                                 return null;
 339
 340                         return types;
 341                 }
 342
 343                 /// <summary>
 344                 ///   Returns the type of a given parameter, and stores in the `is_out'
 345                 ///   boolean whether this is an out or ref parameter.
 346                 ///
 347                 ///   Note that the returned type will not contain any dereference in this
 348                 ///   case (ie, you get "int" for a ref int instead of "int&"
 349                 /// </summary>
 350                 public Type GetParameterInfo (DeclSpace ds, int idx, out bool is_out)
 351                 {
 352                         is_out = false;
 353
 354                         if (!VerifyArgs ()){
 355                                 FixedParameters = null;
 356                                 return null;
 357                         }
 358
 359                         if (FixedParameters == null && ArrayParameter == null)
 360                                 return null;
 361
 362                         if (types == null)
 363                                 if (ComputeParameterTypes (ds) == false){
 364                                         is_out = false;
 365                                         return null;
 366                                 }
 367
 368                         //
 369                         // If this is a request for the variable lenght arg.
 370                         //
 371                         int array_idx = (FixedParameters != null ? FixedParameters.Length : 0);
 372                         if (idx == array_idx){
 373                                 is_out = false;
 374                                 return types [idx];
 375                         }
 376
 377                         //
 378                         // Otherwise, it is a fixed parameter
 379                         //
 380                         Parameter p = FixedParameters [idx];
 381                         is_out = ((p.ModFlags & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) != 0);
 382
 383                         return p.ParameterType;
 384                 }
 385
 386                 public CallingConventions GetCallingConvention ()
 387                 {
 388                         // For now this is the only correc thing to do
 389                         return CallingConventions.Standard;
 390                 }
 391         }
 392 }
 393
 394
 395