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                         //
 130                         // FIXME: There was a MonoTODO, but it does not explain what the problem is
 131                         //
 132                         public override MethodBase BindToMethod (BindingFlags bindingAttr, MethodBase[] match, ref object[] args, ParameterModifier[] modifiers, CultureInfo culture, string[] names, out object state)
 133                         {
 134                                 Type[] types;
 135                                 if (args == null)
 136                                         types = Type.EmptyTypes;
 137                                 else {
 138                                         types = new Type [args.Length];
 139                                         for (int i = 0; i < args.Length; ++i) {
 140                                                 if (args [i] != null)
 141                                                         types [i] = args [i].GetType ();
 142                                         }
 143                                 }
 144                                 MethodBase selected = SelectMethod (bindingAttr, match, types, modifiers);
 145                                 state = null;
 146                                 if (names != null)
 147                                         ReorderParameters (names, ref args, selected);
 148                                 return selected;
 149                         }
 150
 151                         void ReorderParameters (string [] names, ref object [] args, MethodBase selected)
 152                         {
 153                                 object [] newArgs = new object [args.Length];
 154                                 Array.Copy (args, newArgs, args.Length);
 155                                 ParameterInfo [] plist = selected.GetParameters ();
 156                                 for (int n = 0; n < names.Length; n++)
 157                                         for (int p = 0; p < plist.Length; p++) {
 158                                                 if (names [n] == plist [p].Name) {
 159                                                         newArgs [p] = args [n];
 160                                                         break;
 161                                                 }
 162                                         }
 163                                 Array.Copy (newArgs, args, args.Length);
 164                         }
 165
 166                         static bool IsArrayAssignable (Type object_type, Type target_type)
 167                         {
 168                                 if (object_type.IsArray && target_type.IsArray)
 169                                         return IsArrayAssignable (object_type.GetElementType (), target_type.GetElementType ());
 170
 171                                 if (target_type.IsAssignableFrom (object_type))
 172                                         return true;
 173
 174                                 return false;
 175                         }
 176
 177                         public override object ChangeType (object value, Type type, CultureInfo culture)
 178                         {
 179                                 if (value == null)
 180                                         return null;
 181                                 Type vtype = value.GetType ();
 182                                 if (type.IsByRef)
 183                                         type = type.GetElementType ();
 184                                 if (vtype == type || type.IsInstanceOfType (value))
 185                                         return value;
 186                                 if (vtype.IsArray && type.IsArray){
 187                                         if (IsArrayAssignable (vtype.GetElementType (), type.GetElementType ()))
 188                                                 return value;
 189                                 }
 190
 191                                 if (check_type (vtype, type))
 192                                         return Convert.ChangeType (value, type);
 193                                 return null;
 194                         }
 195
 196                         [MonoTODO ("This method does not do anything in Mono")]
 197                         public override void ReorderArgumentArray (ref object[] args, object state)
 198                         {
 199                                 //do nothing until we support named arguments
 200                                 //throw new NotImplementedException ();
 201                         }
 202
 203                         private static bool check_type (Type from, Type to) {
 204                                 if (from == to)
 205                                         return true;
 206
 207                                 if (from == null)
 208                                         return true;
 209
 210                                 TypeCode fromt = Type.GetTypeCode (from);
 211                                 TypeCode tot = Type.GetTypeCode (to);
 212
 213                                 if (to.IsByRef != from.IsByRef)
 214                                         return false;
 215
 216                                 if (to.IsInterface)
 217                                         return to.IsAssignableFrom (from);
 218
 219                                 switch (fromt) {
 220                                 case TypeCode.Char:
 221                                         switch (tot) {
 222                                         case TypeCode.UInt16:
 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);
 232                                 case TypeCode.Byte:
 233                                         switch (tot) {
 234                                         case TypeCode.Char:
 235                                         case TypeCode.UInt16:
 236                                         case TypeCode.Int16:
 237                                         case TypeCode.UInt32:
 238                                         case TypeCode.Int32:
 239                                         case TypeCode.UInt64:
 240                                         case TypeCode.Int64:
 241                                         case TypeCode.Single:
 242                                         case TypeCode.Double:
 243                                                 return true;
 244                                         }
 245                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 246                                 case TypeCode.SByte:
 247                                         switch (tot) {
 248                                         case TypeCode.Int16:
 249                                         case TypeCode.Int32:
 250                                         case TypeCode.Int64:
 251                                         case TypeCode.Single:
 252                                         case TypeCode.Double:
 253                                                 return true;
 254                                         }
 255                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 256                                 case TypeCode.UInt16:
 257                                         switch (tot) {
 258                                         case TypeCode.UInt32:
 259                                         case TypeCode.Int32:
 260                                         case TypeCode.UInt64:
 261                                         case TypeCode.Int64:
 262                                         case TypeCode.Single:
 263                                         case TypeCode.Double:
 264                                                 return true;
 265                                         }
 266                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 267                                 case TypeCode.Int16:
 268                                         switch (tot) {
 269                                         case TypeCode.Int32:
 270                                         case TypeCode.Int64:
 271                                         case TypeCode.Single:
 272                                         case TypeCode.Double:
 273                                                 return true;
 274                                         }
 275                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 276                                 case TypeCode.UInt32:
 277                                         switch (tot) {
 278                                         case TypeCode.UInt64:
 279                                         case TypeCode.Int64:
 280                                         case TypeCode.Single:
 281                                         case TypeCode.Double:
 282                                                 return true;
 283                                         }
 284                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 285                                 case TypeCode.Int32:
 286                                         switch (tot) {
 287                                         case TypeCode.Int64:
 288                                         case TypeCode.Single:
 289                                         case TypeCode.Double:
 290                                                 return true;
 291                                         }
 292                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 293                                 case TypeCode.UInt64:
 294                                 case TypeCode.Int64:
 295                                         switch (tot) {
 296                                         case TypeCode.Single:
 297                                         case TypeCode.Double:
 298                                                 return true;
 299                                         }
 300                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 301                                 case TypeCode.Single:
 302                                         return tot == TypeCode.Double || to == typeof (object);
 303                                 default:
 304                                         /* TODO: handle valuetype -> byref */
 305                                         if (to == typeof (object) && from.IsValueType)
 306                                                 return true;
 307
 308                                         return to.IsAssignableFrom (from);
 309                                 }
 310                         }
 311
 312                         private static bool check_arguments (Type[] types, ParameterInfo[] args) {
 313                                 for (int i = 0; i < types.Length; ++i) {
 314                                         if (!check_type (types [i], args [i].ParameterType))
 315                                                 return false;
 316                                 }
 317                                 return true;
 318                         }
 319
 320                         public override MethodBase SelectMethod (BindingFlags bindingAttr, MethodBase[] match, Type[] types, ParameterModifier[] modifiers)
 321                         {
 322                                 MethodBase m;
 323                                 int i, j;
 324
 325                                 if (match == null)
 326                                         throw new ArgumentNullException ("match");
 327
 328                                 /* first look for an exact match... */
 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                                         for (j = 0; j < types.Length; ++j) {
 335                                                 if (types [j] != args [j].ParameterType)
 336                                                         break;
 337                                         }
 338                                         if (j == types.Length)
 339                                                 return m;
 340                                 }
 341
 342                                 if ((int)(bindingAttr & BindingFlags.ExactBinding) != 0)
 343                                         return null;
 344
 345                                 MethodBase result = null;
 346                                 for (i = 0; i < match.Length; ++i) {
 347                                         m = match [i];
 348                                         ParameterInfo[] args = m.GetParameters ();
 349                                         if (args.Length != types.Length)
 350                                                 continue;
 351                                         if (!check_arguments (types, args))
 352                                                 continue;
 353
 354                                         if (result != null)
 355                                                 result = GetBetterMethod (result, m, types);
 356                                         else
 357                                                 result = m;
 358                                 }
 359
 360                                 return result;
 361                         }
 362
 363                         MethodBase GetBetterMethod (MethodBase m1, MethodBase m2, Type [] types)
 364                         {
 365 #if NET_2_0
 366                                 if (m1.IsGenericMethodDefinition &&
 367                                     !m2.IsGenericMethodDefinition)
 368                                         return m2;
 369                                 if (m2.IsGenericMethodDefinition &&
 370                                     !m1.IsGenericMethodDefinition)
 371                                         return m1;
 372 #endif
 373
 374                                 ParameterInfo [] pl1 = m1.GetParameters ();
 375                                 ParameterInfo [] pl2 = m2.GetParameters ();
 376                                 int prev = 0;
 377                                 for (int i = 0; i < pl1.Length; i++) {
 378                                         int cmp = CompareCloserType (pl1 [i].ParameterType, pl2 [i].ParameterType);
 379                                         if (cmp != 0 && prev != 0 && prev != cmp)
 380                                                 throw new AmbiguousMatchException ();
 381                                         if (cmp != 0)
 382                                                 prev = cmp;
 383                                 }
 384                                 if (prev != 0)
 385                                         return prev > 0 ? m2 : m1;
 386
 387                                 bool va1 = (m1.CallingConvention & CallingConventions.VarArgs) != 0;
 388                                 bool va2 = (m1.CallingConvention & CallingConventions.VarArgs) != 0;
 389                                 if (va1 && !va2)
 390                                         return m2;
 391                                 if (va2 && !va1)
 392                                         return m1;
 393
 394                                 throw new AmbiguousMatchException ();
 395                         }
 396
 397                         int CompareCloserType (Type t1, Type t2)
 398                         {
 399                                 if (t1 == t2)
 400                                         return 0;
 401 #if NET_2_0
 402                                 if (t1.IsGenericParameter && !t2.IsGenericParameter)
 403                                         return 1; // t2
 404                                 if (!t1.IsGenericParameter && t2.IsGenericParameter)
 405                                         return -1; // t1
 406 #endif
 407                                 if (t1.HasElementType && t2.HasElementType)
 408                                         return CompareCloserType (
 409                                                 t1.GetElementType (),
 410                                                 t2.GetElementType ());
 411
 412                                 if (t1.IsSubclassOf (t2))
 413                                         return -1; // t1
 414                                 if (t2.IsSubclassOf (t1))
 415                                         return 1; // t2
 416
 417                                 if (t1.IsInterface && Array.IndexOf (t2.GetInterfaces (), t1) >= 0)
 418                                         return 1; // t2
 419                                 if (t2.IsInterface && Array.IndexOf (t1.GetInterfaces (), t2) >= 0)
 420                                         return -1; // t1
 421
 422                                 // What kind of cases could reach here?
 423                                 return 0;
 424                         }
 425
 426                         public override PropertyInfo SelectProperty (BindingFlags bindingAttr, PropertyInfo[] match, Type returnType, Type[] indexes, ParameterModifier[] modifiers)
 427                         {
 428                                 if (match == null || match.Length == 0)
 429                                         throw new ArgumentException ("No properties provided", "match");
 430
 431                                 bool haveRet = (returnType != null);
 432                                 int idxlen = (indexes != null) ? indexes.Length : -1;
 433                                 PropertyInfo result = null;
 434                                 int i;
 435                                 int best_score = Int32.MaxValue - 1;
 436                                 int fail_score = Int32.MaxValue;
 437                                 int level = 0;
 438
 439                                 for (i = match.Length - 1; i >= 0; i--) {
 440                                         PropertyInfo p = match [i];
 441                                         ParameterInfo[] args = p.GetIndexParameters ();
 442                                         if (idxlen >= 0 && idxlen != args.Length)
 443                                                 continue;
 444
 445                                         if (haveRet && !check_type (p.PropertyType, returnType))
 446                                                 continue;
 447
 448                                         int score = Int32.MaxValue - 1;
 449                                         if (idxlen > 0) {
 450                                                 score = check_arguments_with_score (indexes, args);
 451                                                 if (score == -1)
 452                                                         continue;
 453                                         }
 454
 455                                         int new_level = GetDerivedLevel (p.DeclaringType);
 456                                         if (result != null) {
 457                                                 if (best_score < score)
 458                                                         continue;
 459
 460                                                 if (best_score == score) {
 461                                                         if (level == new_level) {
 462                                                                 // Keep searching. May be there's something
 463                                                                 // better for us.
 464                                                                 fail_score = score;
 465                                                                 continue;
 466                                                         }
 467
 468                                                         if (level > new_level)
 469                                                                 continue;
 470                                                 }
 471                                         }
 472
 473                                         result = p;
 474                                         best_score = score;
 475                                         level = new_level;
 476                                 }
 477
 478                                 if (fail_score <= best_score)
 479                                         throw new AmbiguousMatchException ();
 480
 481                                 return result;
 482                         }
 483
 484                         static int check_arguments_with_score (Type [] types, ParameterInfo [] args)
 485                         {
 486                                 int worst = -1;
 487
 488                                 for (int i = 0; i < types.Length; ++i) {
 489                                         int res = check_type_with_score (types [i], args [i].ParameterType);
 490                                         if (res == -1)
 491                                                 return -1;
 492
 493                                         if (worst < res)
 494                                                 worst = res;
 495                                 }
 496
 497                                 return worst;
 498                         }
 499
 500                         // 0 -> same type or null and !valuetype
 501                         // 1 -> to == Enum
 502                         // 2 -> value type that don't lose data
 503                         // 3 -> to == IsAssignableFrom
 504                         // 4 -> to == object
 505                         static int check_type_with_score (Type from, Type to)
 506                         {
 507                                 if (from == null)
 508                                         return to.IsValueType ? -1 : 0;
 509
 510                                 if (from == to)
 511                                         return 0;
 512
 513                                 if (to == typeof (object))
 514                                         return 4;
 515
 516                                 TypeCode fromt = Type.GetTypeCode (from);
 517                                 TypeCode tot = Type.GetTypeCode (to);
 518
 519                                 switch (fromt) {
 520                                 case TypeCode.Char:
 521                                         switch (tot) {
 522                                         case TypeCode.UInt16:
 523                                                 return 0;
 524
 525                                         case TypeCode.UInt32:
 526                                         case TypeCode.Int32:
 527                                         case TypeCode.UInt64:
 528                                         case TypeCode.Int64:
 529                                         case TypeCode.Single:
 530                                         case TypeCode.Double:
 531                                                 return 2;
 532                                         }
 533                                         return -1;
 534                                 case TypeCode.Byte:
 535                                         switch (tot) {
 536                                         case TypeCode.Char:
 537                                         case TypeCode.UInt16:
 538                                         case TypeCode.Int16:
 539                                         case TypeCode.UInt32:
 540                                         case TypeCode.Int32:
 541                                         case TypeCode.UInt64:
 542                                         case TypeCode.Int64:
 543                                         case TypeCode.Single:
 544                                         case TypeCode.Double:
 545                                                 return 2;
 546                                         }
 547                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 548                                 case TypeCode.SByte:
 549                                         switch (tot) {
 550                                         case TypeCode.Int16:
 551                                         case TypeCode.Int32:
 552                                         case TypeCode.Int64:
 553                                         case TypeCode.Single:
 554                                         case TypeCode.Double:
 555                                                 return 2;
 556                                         }
 557                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 558                                 case TypeCode.UInt16:
 559                                         switch (tot) {
 560                                         case TypeCode.UInt32:
 561                                         case TypeCode.Int32:
 562                                         case TypeCode.UInt64:
 563                                         case TypeCode.Int64:
 564                                         case TypeCode.Single:
 565                                         case TypeCode.Double:
 566                                                 return 2;
 567                                         }
 568                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 569                                 case TypeCode.Int16:
 570                                         switch (tot) {
 571                                         case TypeCode.Int32:
 572                                         case TypeCode.Int64:
 573                                         case TypeCode.Single:
 574                                         case TypeCode.Double:
 575                                                 return 2;
 576                                         }
 577                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 578                                 case TypeCode.UInt32:
 579                                         switch (tot) {
 580                                         case TypeCode.UInt64:
 581                                         case TypeCode.Int64:
 582                                         case TypeCode.Single:
 583                                         case TypeCode.Double:
 584                                                 return 2;
 585                                         }
 586                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 587                                 case TypeCode.Int32:
 588                                         switch (tot) {
 589                                         case TypeCode.Int64:
 590                                         case TypeCode.Single:
 591                                         case TypeCode.Double:
 592                                                 return 2;
 593                                         }
 594                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 595                                 case TypeCode.UInt64:
 596                                 case TypeCode.Int64:
 597                                         switch (tot) {
 598                                         case TypeCode.Single:
 599                                         case TypeCode.Double:
 600                                                 return 2;
 601                                         }
 602                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 603                                 case TypeCode.Single:
 604                                         return tot == TypeCode.Double ? 2 : -1;
 605                                 default:
 606                                         return (to.IsAssignableFrom (from)) ? 3 : -1;
 607                                 }
 608                         }
 609                 }
 610         }
 611 }
 612