mcs/class/corlib/System.Reflection/Binder.cs

   1 // System.Reflection.Binder
   2 //
   3 // Authors:
   4 //      Sean MacIsaac (macisaac@ximian.com)
   5 //      Paolo Molaro (lupus@ximian.com)
   6 //      Gonzalo Paniagua Javier (gonzalo@ximian.com)
   7 //
   8 // (C) Ximian, Inc. 2001 - 2003
   9 // (c) Copyright 2004 Novell, Inc. (http://www.novell.com)
  10
  11 //
  12 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  13 //
  14 // Permission is hereby granted, free of charge, to any person obtaining
  15 // a copy of this software and associated documentation files (the
  16 // "Software"), to deal in the Software without restriction, including
  17 // without limitation the rights to use, copy, modify, merge, publish,
  18 // distribute, sublicense, and/or sell copies of the Software, and to
  19 // permit persons to whom the Software is furnished to do so, subject to
  20 // the following conditions:
  21 //
  22 // The above copyright notice and this permission notice shall be
  23 // included in all copies or substantial portions of the Software.
  24 //
  25 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  26 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  27 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  28 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  29 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  30 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  31 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  32 //
  33
  34 using System.Globalization;
  35 using System.Runtime.InteropServices;
  36
  37 namespace System.Reflection
  38 {
  39         [Serializable]
  40         [ClassInterface(ClassInterfaceType.AutoDual)]
  41         public abstract class Binder
  42         {
  43                 protected Binder () {}
  44
  45                 public abstract FieldInfo BindToField (BindingFlags bindingAttr, FieldInfo[] match, object value, CultureInfo culture);
  46                 public abstract MethodBase BindToMethod (BindingFlags bindingAttr, MethodBase[] match, ref object[] args, ParameterModifier[] modifiers, CultureInfo culture, string[] names, out object state);
  47                 public abstract object ChangeType (object value, Type type, CultureInfo culture);
  48                 public abstract void ReorderArgumentArray( ref object[] args, object state);
  49                 public abstract MethodBase SelectMethod (BindingFlags bindingAttr, MethodBase[] match, Type[] types, ParameterModifier[] modifiers);
  50                 public abstract PropertyInfo SelectProperty( BindingFlags bindingAttr, PropertyInfo[] match, Type returnType, Type[] indexes, ParameterModifier[] modifiers);
  51
  52                 static Binder default_binder;
  53
  54                 internal static Binder DefaultBinder {
  55                         get {
  56                                 if (null == default_binder)
  57                                 {
  58                                         lock (typeof (Binder))
  59                                         {
  60                                                 if (default_binder == null)
  61                                                         default_binder = new Default ();
  62
  63                                                 return default_binder;
  64                                         }
  65                                 }
  66
  67                                 return default_binder;
  68                         }
  69                 }
  70
  71                 internal static bool ConvertArgs (Binder binder, object[] args, ParameterInfo[] pinfo, CultureInfo culture) {
  72                         if (args == null) {
  73                                 if ( pinfo.Length == 0)
  74                                         return true;
  75                                 else
  76                                         throw new TargetParameterCountException ();
  77                         }
  78                         if (pinfo.Length != args.Length)
  79                                 throw new TargetParameterCountException ();
  80                         for (int i = 0; i < args.Length; ++i) {
  81                                 object v = binder.ChangeType (args [i], pinfo[i].ParameterType, culture);
  82                                 if ((v == null) && (args [i] != null))
  83                                         return false;
  84                                 args [i] = v;
  85                         }
  86                         return true;
  87                 }
  88
  89                 internal static int GetDerivedLevel (Type type)
  90                 {
  91                         Type searchType = type;
  92                         int level = 1;
  93
  94                         while (searchType.BaseType != null)
  95                         {
  96                                 level++;
  97                                 searchType = searchType.BaseType;
  98                         }
  99
 100                         return level;
 101                 }
 102
 103                 internal static MethodBase FindMostDerivedMatch (MethodBase [] match)
 104                 {
 105                         int highLevel = 0;
 106                         int matchId = -1;
 107                         int count = match.Length;
 108
 109                         for (int current = 0; current < count; current++)
 110                         {
 111                                 int level = GetDerivedLevel (match[current].DeclaringType);
 112                                 if (level == highLevel)
 113                                         throw new AmbiguousMatchException ();
 114
 115                                 if (level > highLevel)
 116                                 {
 117                                         highLevel = level;
 118                                         matchId = current;
 119                                 }
 120                         }
 121
 122                         return match[matchId];
 123                 }
 124
 125                 internal sealed class Default : Binder {
 126                         public override FieldInfo BindToField (BindingFlags bindingAttr, FieldInfo[] match, object value, CultureInfo culture)
 127                         {
 128                                 if (match == null)
 129                                         throw new ArgumentNullException ("match");
 130                                 foreach (FieldInfo f in match) {
 131                                         if (check_type (value.GetType (), f.FieldType))
 132                                                 return f;
 133                                 }
 134                                 return null;
 135                         }
 136
 137                         [MonoTODO]
 138                         public override MethodBase BindToMethod (BindingFlags bindingAttr, MethodBase[] match, ref object[] args, ParameterModifier[] modifiers, CultureInfo culture, string[] names, out object state)
 139                         {
 140                                 Type[] types;
 141                                 if (args == null)
 142                                         types = Type.EmptyTypes;
 143                                 else {
 144                                         types = new Type [args.Length];
 145                                         for (int i = 0; i < args.Length; ++i) {
 146                                                 if (args [i] != null)
 147                                                         types [i] = args [i].GetType ();
 148                                         }
 149                                 }
 150                                 MethodBase selected = SelectMethod (bindingAttr, match, types, modifiers);
 151                                 state = null;
 152                                 return selected;
 153                         }
 154
 155                         static bool IsArrayAssignable (Type object_type, Type target_type)
 156                         {
 157                                 if (object_type.IsArray && target_type.IsArray)
 158                                         return IsArrayAssignable (object_type.GetElementType (), target_type.GetElementType ());
 159
 160                                 if (target_type.IsAssignableFrom (object_type))
 161                                         return true;
 162
 163                                 return false;
 164                         }
 165
 166                         public override object ChangeType (object value, Type type, CultureInfo culture)
 167                         {
 168                                 if (value == null)
 169                                         return null;
 170                                 Type vtype = value.GetType ();
 171                                 if (type.IsByRef)
 172                                         type = type.GetElementType ();
 173                                 if (vtype == type || type.IsAssignableFrom (vtype))
 174                                         return value;
 175                                 if (vtype.IsArray && type.IsArray){
 176                                         if (IsArrayAssignable (vtype.GetElementType (), type.GetElementType ()))
 177                                                 return value;
 178                                 }
 179
 180                                 if (check_type (vtype, type))
 181                                         return Convert.ChangeType (value, type);
 182                                 return null;
 183                         }
 184
 185                         [MonoTODO]
 186                         public override void ReorderArgumentArray (ref object[] args, object state)
 187                         {
 188                                 //do nothing until we support named arguments
 189                                 //throw new NotImplementedException ();
 190                         }
 191
 192                         private static bool check_type (Type from, Type to) {
 193                                 if (from == to)
 194                                         return true;
 195
 196                                 if (from == null)
 197                                         return !to.IsValueType;
 198
 199                                 TypeCode fromt = Type.GetTypeCode (from);
 200                                 TypeCode tot = Type.GetTypeCode (to);
 201
 202                                 if (to.IsByRef != from.IsByRef)
 203                                         return false;
 204
 205                                 switch (fromt) {
 206                                 case TypeCode.Char:
 207                                         switch (tot) {
 208                                         case TypeCode.UInt16:
 209                                         case TypeCode.UInt32:
 210                                         case TypeCode.Int32:
 211                                         case TypeCode.UInt64:
 212                                         case TypeCode.Int64:
 213                                         case TypeCode.Single:
 214                                         case TypeCode.Double:
 215                                                 return true;
 216                                         }
 217                                         return to == typeof (object);
 218                                 case TypeCode.Byte:
 219                                         switch (tot) {
 220                                         case TypeCode.Char:
 221                                         case TypeCode.UInt16:
 222                                         case TypeCode.Int16:
 223                                         case TypeCode.UInt32:
 224                                         case TypeCode.Int32:
 225                                         case TypeCode.UInt64:
 226                                         case TypeCode.Int64:
 227                                         case TypeCode.Single:
 228                                         case TypeCode.Double:
 229                                                 return true;
 230                                         }
 231                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 232                                 case TypeCode.SByte:
 233                                         switch (tot) {
 234                                         case TypeCode.Int16:
 235                                         case TypeCode.Int32:
 236                                         case TypeCode.Int64:
 237                                         case TypeCode.Single:
 238                                         case TypeCode.Double:
 239                                                 return true;
 240                                         }
 241                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 242                                 case TypeCode.UInt16:
 243                                         switch (tot) {
 244                                         case TypeCode.UInt32:
 245                                         case TypeCode.Int32:
 246                                         case TypeCode.UInt64:
 247                                         case TypeCode.Int64:
 248                                         case TypeCode.Single:
 249                                         case TypeCode.Double:
 250                                                 return true;
 251                                         }
 252                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 253                                 case TypeCode.Int16:
 254                                         switch (tot) {
 255                                         case TypeCode.Int32:
 256                                         case TypeCode.Int64:
 257                                         case TypeCode.Single:
 258                                         case TypeCode.Double:
 259                                                 return true;
 260                                         }
 261                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 262                                 case TypeCode.UInt32:
 263                                         switch (tot) {
 264                                         case TypeCode.UInt64:
 265                                         case TypeCode.Int64:
 266                                         case TypeCode.Single:
 267                                         case TypeCode.Double:
 268                                                 return true;
 269                                         }
 270                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 271                                 case TypeCode.Int32:
 272                                         switch (tot) {
 273                                         case TypeCode.Int64:
 274                                         case TypeCode.Single:
 275                                         case TypeCode.Double:
 276                                                 return true;
 277                                         }
 278                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 279                                 case TypeCode.UInt64:
 280                                 case TypeCode.Int64:
 281                                         switch (tot) {
 282                                         case TypeCode.Single:
 283                                         case TypeCode.Double:
 284                                                 return true;
 285                                         }
 286                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 287                                 case TypeCode.Single:
 288                                         return tot == TypeCode.Double || to == typeof (object);
 289                                 default:
 290                                         /* TODO: handle valuetype -> byref */
 291                                         if (to == typeof (object) && from.IsValueType)
 292                                                 return true;
 293
 294                                         return to.IsAssignableFrom (from);
 295                                 }
 296                         }
 297
 298                         private static bool check_arguments (Type[] types, ParameterInfo[] args) {
 299                                 for (int i = 0; i < types.Length; ++i) {
 300                                         if (!check_type (types [i], args [i].ParameterType))
 301                                                 return false;
 302                                 }
 303                                 return true;
 304                         }
 305
 306                         public override MethodBase SelectMethod (BindingFlags bindingAttr, MethodBase[] match, Type[] types, ParameterModifier[] modifiers)
 307                         {
 308                                 MethodBase m;
 309                                 int i, j;
 310
 311                                 if (match == null)
 312                                         throw new ArgumentNullException ("match");
 313
 314                                 /* first look for an exact match... */
 315                                 for (i = 0; i < match.Length; ++i) {
 316                                         m = match [i];
 317                                         ParameterInfo[] args = m.GetParameters ();
 318                                         if (args.Length != types.Length)
 319                                                 continue;
 320                                         for (j = 0; j < types.Length; ++j) {
 321                                                 if (types [j] != args [j].ParameterType)
 322                                                         break;
 323                                         }
 324                                         if (j == types.Length)
 325                                                 return m;
 326                                 }
 327
 328                                 MethodBase result = null;
 329                                 for (i = 0; i < match.Length; ++i) {
 330                                         m = match [i];
 331                                         ParameterInfo[] args = m.GetParameters ();
 332                                         if (args.Length != types.Length)
 333                                                 continue;
 334                                         if (!check_arguments (types, args))
 335                                                 continue;
 336
 337                                         if (result != null)
 338                                                 throw new AmbiguousMatchException ();
 339
 340                                         result = m;
 341                                 }
 342
 343                                 return result;
 344                         }
 345
 346                         public override PropertyInfo SelectProperty (BindingFlags bindingAttr, PropertyInfo[] match, Type returnType, Type[] indexes, ParameterModifier[] modifiers)
 347                         {
 348                                 if (match == null || match.Length == 0)
 349                                         throw new ArgumentException ("No properties provided", "match");
 350
 351                                 bool haveRet = (returnType != null);
 352                                 int idxlen = (indexes != null) ? indexes.Length : -1;
 353                                 PropertyInfo result = null;
 354                                 int i;
 355                                 int best_score = Int32.MaxValue - 1;
 356                                 int fail_score = Int32.MaxValue;
 357                                 int level = 0;
 358
 359                                 for (i = match.Length - 1; i >= 0; i--) {
 360                                         PropertyInfo p = match [i];
 361                                         ParameterInfo[] args = p.GetIndexParameters ();
 362                                         if (idxlen >= 0 && idxlen != args.Length)
 363                                                 continue;
 364
 365                                         if (haveRet && !check_type (p.PropertyType, returnType))
 366                                                 continue;
 367
 368                                         int score = Int32.MaxValue - 1;
 369                                         if (idxlen > 0) {
 370                                                 score = check_arguments_with_score (indexes, args);
 371                                                 if (score == -1)
 372                                                         continue;
 373                                         }
 374
 375                                         int new_level = GetDerivedLevel (p.DeclaringType);
 376                                         if (result != null) {
 377                                                 if (best_score < score)
 378                                                         continue;
 379
 380                                                 if (best_score == score) {
 381                                                         if (level == new_level) {
 382                                                                 // Keep searching. May be there's something
 383                                                                 // better for us.
 384                                                                 fail_score = score;
 385                                                                 continue;
 386                                                         }
 387
 388                                                         if (level > new_level)
 389                                                                 continue;
 390                                                 }
 391                                         }
 392
 393                                         result = p;
 394                                         best_score = score;
 395                                         level = new_level;
 396                                 }
 397
 398                                 if (fail_score <= best_score)
 399                                         throw new AmbiguousMatchException ();
 400
 401                                 return result;
 402                         }
 403
 404                         static int check_arguments_with_score (Type [] types, ParameterInfo [] args)
 405                         {
 406                                 int worst = -1;
 407
 408                                 for (int i = 0; i < types.Length; ++i) {
 409                                         int res = check_type_with_score (types [i], args [i].ParameterType);
 410                                         if (res == -1)
 411                                                 return -1;
 412
 413                                         if (worst < res)
 414                                                 worst = res;
 415                                 }
 416
 417                                 return worst;
 418                         }
 419
 420                         // 0 -> same type or null and !valuetype
 421                         // 1 -> to == Enum
 422                         // 2 -> value type that don't lose data
 423                         // 3 -> to == IsAssignableFrom
 424                         // 4 -> to == object
 425                         static int check_type_with_score (Type from, Type to)
 426                         {
 427                                 if (from == null)
 428                                         return to.IsValueType ? -1 : 0;
 429
 430                                 if (from == to)
 431                                         return 0;
 432
 433                                 if (to == typeof (object))
 434                                         return 4;
 435
 436                                 TypeCode fromt = Type.GetTypeCode (from);
 437                                 TypeCode tot = Type.GetTypeCode (to);
 438
 439                                 switch (fromt) {
 440                                 case TypeCode.Char:
 441                                         switch (tot) {
 442                                         case TypeCode.UInt16:
 443                                                 return 0;
 444
 445                                         case TypeCode.UInt32:
 446                                         case TypeCode.Int32:
 447                                         case TypeCode.UInt64:
 448                                         case TypeCode.Int64:
 449                                         case TypeCode.Single:
 450                                         case TypeCode.Double:
 451                                                 return 2;
 452                                         }
 453                                         return -1;
 454                                 case TypeCode.Byte:
 455                                         switch (tot) {
 456                                         case TypeCode.Char:
 457                                         case TypeCode.UInt16:
 458                                         case TypeCode.Int16:
 459                                         case TypeCode.UInt32:
 460                                         case TypeCode.Int32:
 461                                         case TypeCode.UInt64:
 462                                         case TypeCode.Int64:
 463                                         case TypeCode.Single:
 464                                         case TypeCode.Double:
 465                                                 return 2;
 466                                         }
 467                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 468                                 case TypeCode.SByte:
 469                                         switch (tot) {
 470                                         case TypeCode.Int16:
 471                                         case TypeCode.Int32:
 472                                         case TypeCode.Int64:
 473                                         case TypeCode.Single:
 474                                         case TypeCode.Double:
 475                                                 return 2;
 476                                         }
 477                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 478                                 case TypeCode.UInt16:
 479                                         switch (tot) {
 480                                         case TypeCode.UInt32:
 481                                         case TypeCode.Int32:
 482                                         case TypeCode.UInt64:
 483                                         case TypeCode.Int64:
 484                                         case TypeCode.Single:
 485                                         case TypeCode.Double:
 486                                                 return 2;
 487                                         }
 488                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 489                                 case TypeCode.Int16:
 490                                         switch (tot) {
 491                                         case TypeCode.Int32:
 492                                         case TypeCode.Int64:
 493                                         case TypeCode.Single:
 494                                         case TypeCode.Double:
 495                                                 return 2;
 496                                         }
 497                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 498                                 case TypeCode.UInt32:
 499                                         switch (tot) {
 500                                         case TypeCode.UInt64:
 501                                         case TypeCode.Int64:
 502                                         case TypeCode.Single:
 503                                         case TypeCode.Double:
 504                                                 return 2;
 505                                         }
 506                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 507                                 case TypeCode.Int32:
 508                                         switch (tot) {
 509                                         case TypeCode.Int64:
 510                                         case TypeCode.Single:
 511                                         case TypeCode.Double:
 512                                                 return 2;
 513                                         }
 514                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 515                                 case TypeCode.UInt64:
 516                                 case TypeCode.Int64:
 517                                         switch (tot) {
 518                                         case TypeCode.Single:
 519                                         case TypeCode.Double:
 520                                                 return 2;
 521                                         }
 522                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 523                                 case TypeCode.Single:
 524                                         return tot == TypeCode.Double ? 2 : -1;
 525                                 default:
 526                                         return (to.IsAssignableFrom (from)) ? 3 : -1;
 527                                 }
 528                         }
 529                 }
 530         }
 531 }
 532