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 #if NET_2_0
  40         [ComVisible (true)]
  41 #endif
  42         [Serializable]
  43         [ClassInterface(ClassInterfaceType.AutoDual)]
  44         public abstract class Binder
  45         {
  46                 protected Binder () {}
  47
  48                 public abstract FieldInfo BindToField (BindingFlags bindingAttr, FieldInfo[] match, object value, CultureInfo culture);
  49                 public abstract MethodBase BindToMethod (BindingFlags bindingAttr, MethodBase[] match, ref object[] args, ParameterModifier[] modifiers, CultureInfo culture, string[] names, out object state);
  50                 public abstract object ChangeType (object value, Type type, CultureInfo culture);
  51                 public abstract void ReorderArgumentArray( ref object[] args, object state);
  52                 public abstract MethodBase SelectMethod (BindingFlags bindingAttr, MethodBase[] match, Type[] types, ParameterModifier[] modifiers);
  53                 public abstract PropertyInfo SelectProperty( BindingFlags bindingAttr, PropertyInfo[] match, Type returnType, Type[] indexes, ParameterModifier[] modifiers);
  54
  55                 static Binder default_binder = new Default ();
  56
  57                 internal static Binder DefaultBinder {
  58                         get {
  59                                 return default_binder;
  60                         }
  61                 }
  62
  63                 internal static bool ConvertArgs (Binder binder, object[] args, ParameterInfo[] pinfo, CultureInfo culture) {
  64                         if (args == null) {
  65                                 if ( pinfo.Length == 0)
  66                                         return true;
  67                                 else
  68                                         throw new TargetParameterCountException ();
  69                         }
  70                         if (pinfo.Length != args.Length)
  71                                 throw new TargetParameterCountException ();
  72                         for (int i = 0; i < args.Length; ++i) {
  73                                 object v = binder.ChangeType (args [i], pinfo[i].ParameterType, culture);
  74                                 if ((v == null) && (args [i] != null))
  75                                         return false;
  76                                 args [i] = v;
  77                         }
  78                         return true;
  79                 }
  80
  81                 internal static int GetDerivedLevel (Type type)
  82                 {
  83                         Type searchType = type;
  84                         int level = 1;
  85
  86                         while (searchType.BaseType != null)
  87                         {
  88                                 level++;
  89                                 searchType = searchType.BaseType;
  90                         }
  91
  92                         return level;
  93                 }
  94
  95                 internal static MethodBase FindMostDerivedMatch (MethodBase [] match)
  96                 {
  97                         int highLevel = 0;
  98                         int matchId = -1;
  99                         int count = match.Length;
 100
 101                         for (int current = 0; current < count; current++)
 102                         {
 103                                 int level = GetDerivedLevel (match[current].DeclaringType);
 104                                 if (level == highLevel)
 105                                         throw new AmbiguousMatchException ();
 106
 107                                 if (level > highLevel)
 108                                 {
 109                                         highLevel = level;
 110                                         matchId = current;
 111                                 }
 112                         }
 113
 114                         return match[matchId];
 115                 }
 116
 117                 internal sealed class Default : Binder {
 118                         public override FieldInfo BindToField (BindingFlags bindingAttr, FieldInfo[] match, object value, CultureInfo culture)
 119                         {
 120                                 if (match == null)
 121                                         throw new ArgumentNullException ("match");
 122                                 foreach (FieldInfo f in match) {
 123                                         if (check_type (value.GetType (), f.FieldType))
 124                                                 return f;
 125                                 }
 126                                 return null;
 127                         }
 128
 129                         [MonoTODO]
 130                         public override MethodBase BindToMethod (BindingFlags bindingAttr, MethodBase[] match, ref object[] args, ParameterModifier[] modifiers, CultureInfo culture, string[] names, out object state)
 131                         {
 132                                 Type[] types;
 133                                 if (args == null)
 134                                         types = Type.EmptyTypes;
 135                                 else {
 136                                         types = new Type [args.Length];
 137                                         for (int i = 0; i < args.Length; ++i) {
 138                                                 if (args [i] != null)
 139                                                         types [i] = args [i].GetType ();
 140                                         }
 141                                 }
 142                                 MethodBase selected = SelectMethod (bindingAttr, match, types, modifiers);
 143                                 state = null;
 144                                 if (names != null)
 145                                         ReorderParameters (names, ref args, selected);
 146                                 return selected;
 147                         }
 148
 149                         void ReorderParameters (string [] names, ref object [] args, MethodBase selected)
 150                         {
 151                                 ParameterInfo [] plist = selected.GetParameters ();
 152                                 for (int n = 0; n < names.Length; n++)
 153                                         for (int p = 0; p < plist.Length; p++) {
 154                                                 if (names [n] == plist [p].Name) {
 155                                                         object o = args [n];
 156                                                         args [n] = args [p];
 157                                                         args [p] = o;
 158                                                 }
 159                                                 break;
 160                                         }
 161                         }
 162
 163                         static bool IsArrayAssignable (Type object_type, Type target_type)
 164                         {
 165                                 if (object_type.IsArray && target_type.IsArray)
 166                                         return IsArrayAssignable (object_type.GetElementType (), target_type.GetElementType ());
 167
 168                                 if (target_type.IsAssignableFrom (object_type))
 169                                         return true;
 170
 171                                 return false;
 172                         }
 173
 174                         public override object ChangeType (object value, Type type, CultureInfo culture)
 175                         {
 176                                 if (value == null)
 177                                         return null;
 178                                 Type vtype = value.GetType ();
 179                                 if (type.IsByRef)
 180                                         type = type.GetElementType ();
 181                                 if (vtype == type || type.IsInstanceOfType (value))
 182                                         return value;
 183                                 if (vtype.IsArray && type.IsArray){
 184                                         if (IsArrayAssignable (vtype.GetElementType (), type.GetElementType ()))
 185                                                 return value;
 186                                 }
 187
 188                                 if (check_type (vtype, type))
 189                                         return Convert.ChangeType (value, type);
 190                                 return null;
 191                         }
 192
 193                         [MonoTODO]
 194                         public override void ReorderArgumentArray (ref object[] args, object state)
 195                         {
 196                                 //do nothing until we support named arguments
 197                                 //throw new NotImplementedException ();
 198                         }
 199
 200                         private static bool check_type (Type from, Type to) {
 201                                 if (from == to)
 202                                         return true;
 203
 204                                 if (from == null)
 205                                         return true;
 206
 207                                 TypeCode fromt = Type.GetTypeCode (from);
 208                                 TypeCode tot = Type.GetTypeCode (to);
 209
 210                                 if (to.IsByRef != from.IsByRef)
 211                                         return false;
 212
 213                                 if (to.IsInterface)
 214                                         return to.IsAssignableFrom (from);
 215
 216                                 switch (fromt) {
 217                                 case TypeCode.Char:
 218                                         switch (tot) {
 219                                         case TypeCode.UInt16:
 220                                         case TypeCode.UInt32:
 221                                         case TypeCode.Int32:
 222                                         case TypeCode.UInt64:
 223                                         case TypeCode.Int64:
 224                                         case TypeCode.Single:
 225                                         case TypeCode.Double:
 226                                                 return true;
 227                                         }
 228                                         return to == typeof (object);
 229                                 case TypeCode.Byte:
 230                                         switch (tot) {
 231                                         case TypeCode.Char:
 232                                         case TypeCode.UInt16:
 233                                         case TypeCode.Int16:
 234                                         case TypeCode.UInt32:
 235                                         case TypeCode.Int32:
 236                                         case TypeCode.UInt64:
 237                                         case TypeCode.Int64:
 238                                         case TypeCode.Single:
 239                                         case TypeCode.Double:
 240                                                 return true;
 241                                         }
 242                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 243                                 case TypeCode.SByte:
 244                                         switch (tot) {
 245                                         case TypeCode.Int16:
 246                                         case TypeCode.Int32:
 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.UInt16:
 254                                         switch (tot) {
 255                                         case TypeCode.UInt32:
 256                                         case TypeCode.Int32:
 257                                         case TypeCode.UInt64:
 258                                         case TypeCode.Int64:
 259                                         case TypeCode.Single:
 260                                         case TypeCode.Double:
 261                                                 return true;
 262                                         }
 263                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 264                                 case TypeCode.Int16:
 265                                         switch (tot) {
 266                                         case TypeCode.Int32:
 267                                         case TypeCode.Int64:
 268                                         case TypeCode.Single:
 269                                         case TypeCode.Double:
 270                                                 return true;
 271                                         }
 272                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 273                                 case TypeCode.UInt32:
 274                                         switch (tot) {
 275                                         case TypeCode.UInt64:
 276                                         case TypeCode.Int64:
 277                                         case TypeCode.Single:
 278                                         case TypeCode.Double:
 279                                                 return true;
 280                                         }
 281                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 282                                 case TypeCode.Int32:
 283                                         switch (tot) {
 284                                         case TypeCode.Int64:
 285                                         case TypeCode.Single:
 286                                         case TypeCode.Double:
 287                                                 return true;
 288                                         }
 289                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 290                                 case TypeCode.UInt64:
 291                                 case TypeCode.Int64:
 292                                         switch (tot) {
 293                                         case TypeCode.Single:
 294                                         case TypeCode.Double:
 295                                                 return true;
 296                                         }
 297                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 298                                 case TypeCode.Single:
 299                                         return tot == TypeCode.Double || to == typeof (object);
 300                                 default:
 301                                         /* TODO: handle valuetype -> byref */
 302                                         if (to == typeof (object) && from.IsValueType)
 303                                                 return true;
 304
 305                                         return to.IsAssignableFrom (from);
 306                                 }
 307                         }
 308
 309                         private static bool check_arguments (Type[] types, ParameterInfo[] args) {
 310                                 for (int i = 0; i < types.Length; ++i) {
 311                                         if (!check_type (types [i], args [i].ParameterType))
 312                                                 return false;
 313                                 }
 314                                 return true;
 315                         }
 316
 317                         public override MethodBase SelectMethod (BindingFlags bindingAttr, MethodBase[] match, Type[] types, ParameterModifier[] modifiers)
 318                         {
 319                                 MethodBase m;
 320                                 int i, j;
 321
 322                                 if (match == null)
 323                                         throw new ArgumentNullException ("match");
 324
 325                                 /* first look for an exact match... */
 326                                 for (i = 0; i < match.Length; ++i) {
 327                                         m = match [i];
 328                                         ParameterInfo[] args = m.GetParameters ();
 329                                         if (args.Length != types.Length)
 330                                                 continue;
 331                                         for (j = 0; j < types.Length; ++j) {
 332                                                 if (types [j] != args [j].ParameterType)
 333                                                         break;
 334                                         }
 335                                         if (j == types.Length)
 336                                                 return m;
 337                                 }
 338
 339                                 if ((int)(bindingAttr & BindingFlags.ExactBinding) != 0)
 340                                         return null;
 341
 342                                 MethodBase result = null;
 343                                 for (i = 0; i < match.Length; ++i) {
 344                                         m = match [i];
 345                                         ParameterInfo[] args = m.GetParameters ();
 346                                         if (args.Length != types.Length)
 347                                                 continue;
 348                                         if (!check_arguments (types, args))
 349                                                 continue;
 350
 351                                         if (result != null)
 352                                                 result = GetBetterMethod (result, m, types);
 353                                         else
 354                                                 result = m;
 355                                 }
 356
 357                                 return result;
 358                         }
 359
 360                         MethodBase GetBetterMethod (MethodBase m1, MethodBase m2, Type [] types)
 361                         {
 362 #if NET_2_0
 363                                 if (m1.IsGenericMethodDefinition &&
 364                                     !m2.IsGenericMethodDefinition)
 365                                         return m2;
 366                                 if (m2.IsGenericMethodDefinition &&
 367                                     !m1.IsGenericMethodDefinition)
 368                                         return m1;
 369 #endif
 370
 371                                 ParameterInfo [] pl1 = m1.GetParameters ();
 372                                 ParameterInfo [] pl2 = m2.GetParameters ();
 373                                 int prev = 0;
 374                                 for (int i = 0; i < pl1.Length; i++) {
 375                                         int cmp = CompareCloserType (pl1 [i].ParameterType, pl2 [i].ParameterType);
 376                                         if (cmp != 0 && prev != 0 && prev != cmp)
 377                                                 throw new AmbiguousMatchException ();
 378                                         if (cmp != 0)
 379                                                 prev = cmp;
 380                                 }
 381                                 if (prev != 0)
 382                                         return prev > 0 ? m2 : m1;
 383
 384                                 bool va1 = (m1.CallingConvention & CallingConventions.VarArgs) != 0;
 385                                 bool va2 = (m1.CallingConvention & CallingConventions.VarArgs) != 0;
 386                                 if (va1 && !va2)
 387                                         return m2;
 388                                 if (va2 && !va1)
 389                                         return m1;
 390
 391                                 throw new AmbiguousMatchException ();
 392                         }
 393
 394                         int CompareCloserType (Type t1, Type t2)
 395                         {
 396                                 if (t1 == t2)
 397                                         return 0;
 398 #if NET_2_0
 399                                 if (t1.IsGenericParameter && !t2.IsGenericParameter)
 400                                         return 1; // t2
 401                                 if (!t1.IsGenericParameter && t2.IsGenericParameter)
 402                                         return -1; // t1
 403 #endif
 404                                 if (t1.HasElementType && t2.HasElementType)
 405                                         return CompareCloserType (
 406                                                 t1.GetElementType (),
 407                                                 t2.GetElementType ());
 408
 409                                 if (t1.IsSubclassOf (t2))
 410                                         return -1; // t1
 411                                 if (t2.IsSubclassOf (t1))
 412                                         return 1; // t2
 413
 414                                 if (t1.IsInterface && Array.IndexOf (t2.GetInterfaces (), t1) >= 0)
 415                                         return 1; // t2
 416                                 if (t2.IsInterface && Array.IndexOf (t1.GetInterfaces (), t2) >= 0)
 417                                         return -1; // t1
 418
 419                                 // What kind of cases could reach here?
 420                                 return 0;
 421                         }
 422
 423                         public override PropertyInfo SelectProperty (BindingFlags bindingAttr, PropertyInfo[] match, Type returnType, Type[] indexes, ParameterModifier[] modifiers)
 424                         {
 425                                 if (match == null || match.Length == 0)
 426                                         throw new ArgumentException ("No properties provided", "match");
 427
 428                                 bool haveRet = (returnType != null);
 429                                 int idxlen = (indexes != null) ? indexes.Length : -1;
 430                                 PropertyInfo result = null;
 431                                 int i;
 432                                 int best_score = Int32.MaxValue - 1;
 433                                 int fail_score = Int32.MaxValue;
 434                                 int level = 0;
 435
 436                                 for (i = match.Length - 1; i >= 0; i--) {
 437                                         PropertyInfo p = match [i];
 438                                         ParameterInfo[] args = p.GetIndexParameters ();
 439                                         if (idxlen >= 0 && idxlen != args.Length)
 440                                                 continue;
 441
 442                                         if (haveRet && !check_type (p.PropertyType, returnType))
 443                                                 continue;
 444
 445                                         int score = Int32.MaxValue - 1;
 446                                         if (idxlen > 0) {
 447                                                 score = check_arguments_with_score (indexes, args);
 448                                                 if (score == -1)
 449                                                         continue;
 450                                         }
 451
 452                                         int new_level = GetDerivedLevel (p.DeclaringType);
 453                                         if (result != null) {
 454                                                 if (best_score < score)
 455                                                         continue;
 456
 457                                                 if (best_score == score) {
 458                                                         if (level == new_level) {
 459                                                                 // Keep searching. May be there's something
 460                                                                 // better for us.
 461                                                                 fail_score = score;
 462                                                                 continue;
 463                                                         }
 464
 465                                                         if (level > new_level)
 466                                                                 continue;
 467                                                 }
 468                                         }
 469
 470                                         result = p;
 471                                         best_score = score;
 472                                         level = new_level;
 473                                 }
 474
 475                                 if (fail_score <= best_score)
 476                                         throw new AmbiguousMatchException ();
 477
 478                                 return result;
 479                         }
 480
 481                         static int check_arguments_with_score (Type [] types, ParameterInfo [] args)
 482                         {
 483                                 int worst = -1;
 484
 485                                 for (int i = 0; i < types.Length; ++i) {
 486                                         int res = check_type_with_score (types [i], args [i].ParameterType);
 487                                         if (res == -1)
 488                                                 return -1;
 489
 490                                         if (worst < res)
 491                                                 worst = res;
 492                                 }
 493
 494                                 return worst;
 495                         }
 496
 497                         // 0 -> same type or null and !valuetype
 498                         // 1 -> to == Enum
 499                         // 2 -> value type that don't lose data
 500                         // 3 -> to == IsAssignableFrom
 501                         // 4 -> to == object
 502                         static int check_type_with_score (Type from, Type to)
 503                         {
 504                                 if (from == null)
 505                                         return to.IsValueType ? -1 : 0;
 506
 507                                 if (from == to)
 508                                         return 0;
 509
 510                                 if (to == typeof (object))
 511                                         return 4;
 512
 513                                 TypeCode fromt = Type.GetTypeCode (from);
 514                                 TypeCode tot = Type.GetTypeCode (to);
 515
 516                                 switch (fromt) {
 517                                 case TypeCode.Char:
 518                                         switch (tot) {
 519                                         case TypeCode.UInt16:
 520                                                 return 0;
 521
 522                                         case TypeCode.UInt32:
 523                                         case TypeCode.Int32:
 524                                         case TypeCode.UInt64:
 525                                         case TypeCode.Int64:
 526                                         case TypeCode.Single:
 527                                         case TypeCode.Double:
 528                                                 return 2;
 529                                         }
 530                                         return -1;
 531                                 case TypeCode.Byte:
 532                                         switch (tot) {
 533                                         case TypeCode.Char:
 534                                         case TypeCode.UInt16:
 535                                         case TypeCode.Int16:
 536                                         case TypeCode.UInt32:
 537                                         case TypeCode.Int32:
 538                                         case TypeCode.UInt64:
 539                                         case TypeCode.Int64:
 540                                         case TypeCode.Single:
 541                                         case TypeCode.Double:
 542                                                 return 2;
 543                                         }
 544                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 545                                 case TypeCode.SByte:
 546                                         switch (tot) {
 547                                         case TypeCode.Int16:
 548                                         case TypeCode.Int32:
 549                                         case TypeCode.Int64:
 550                                         case TypeCode.Single:
 551                                         case TypeCode.Double:
 552                                                 return 2;
 553                                         }
 554                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 555                                 case TypeCode.UInt16:
 556                                         switch (tot) {
 557                                         case TypeCode.UInt32:
 558                                         case TypeCode.Int32:
 559                                         case TypeCode.UInt64:
 560                                         case TypeCode.Int64:
 561                                         case TypeCode.Single:
 562                                         case TypeCode.Double:
 563                                                 return 2;
 564                                         }
 565                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 566                                 case TypeCode.Int16:
 567                                         switch (tot) {
 568                                         case TypeCode.Int32:
 569                                         case TypeCode.Int64:
 570                                         case TypeCode.Single:
 571                                         case TypeCode.Double:
 572                                                 return 2;
 573                                         }
 574                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 575                                 case TypeCode.UInt32:
 576                                         switch (tot) {
 577                                         case TypeCode.UInt64:
 578                                         case TypeCode.Int64:
 579                                         case TypeCode.Single:
 580                                         case TypeCode.Double:
 581                                                 return 2;
 582                                         }
 583                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 584                                 case TypeCode.Int32:
 585                                         switch (tot) {
 586                                         case TypeCode.Int64:
 587                                         case TypeCode.Single:
 588                                         case TypeCode.Double:
 589                                                 return 2;
 590                                         }
 591                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 592                                 case TypeCode.UInt64:
 593                                 case TypeCode.Int64:
 594                                         switch (tot) {
 595                                         case TypeCode.Single:
 596                                         case TypeCode.Double:
 597                                                 return 2;
 598                                         }
 599                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 600                                 case TypeCode.Single:
 601                                         return tot == TypeCode.Double ? 2 : -1;
 602                                 default:
 603                                         return (to.IsAssignableFrom (from)) ? 3 : -1;
 604                                 }
 605                         }
 606                 }
 607         }
 608 }
 609