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                                 object [] newArgs = new object [args.Length];
 152                                 Array.Copy (args, newArgs, args.Length);
 153                                 ParameterInfo [] plist = selected.GetParameters ();
 154                                 for (int n = 0; n < names.Length; n++)
 155                                         for (int p = 0; p < plist.Length; p++) {
 156                                                 if (names [n] == plist [p].Name) {
 157                                                         newArgs [p] = args [n];
 158                                                         break;
 159                                                 }
 160                                         }
 161                                 Array.Copy (newArgs, args, args.Length);
 162                         }
 163
 164                         static bool IsArrayAssignable (Type object_type, Type target_type)
 165                         {
 166                                 if (object_type.IsArray && target_type.IsArray)
 167                                         return IsArrayAssignable (object_type.GetElementType (), target_type.GetElementType ());
 168
 169                                 if (target_type.IsAssignableFrom (object_type))
 170                                         return true;
 171
 172                                 return false;
 173                         }
 174
 175                         public override object ChangeType (object value, Type type, CultureInfo culture)
 176                         {
 177                                 if (value == null)
 178                                         return null;
 179                                 Type vtype = value.GetType ();
 180                                 if (type.IsByRef)
 181                                         type = type.GetElementType ();
 182                                 if (vtype == type || type.IsInstanceOfType (value))
 183                                         return value;
 184                                 if (vtype.IsArray && type.IsArray){
 185                                         if (IsArrayAssignable (vtype.GetElementType (), type.GetElementType ()))
 186                                                 return value;
 187                                 }
 188
 189                                 if (check_type (vtype, type))
 190                                         return Convert.ChangeType (value, type);
 191                                 return null;
 192                         }
 193
 194                         [MonoTODO]
 195                         public override void ReorderArgumentArray (ref object[] args, object state)
 196                         {
 197                                 //do nothing until we support named arguments
 198                                 //throw new NotImplementedException ();
 199                         }
 200
 201                         private static bool check_type (Type from, Type to) {
 202                                 if (from == to)
 203                                         return true;
 204
 205                                 if (from == null)
 206                                         return true;
 207
 208                                 TypeCode fromt = Type.GetTypeCode (from);
 209                                 TypeCode tot = Type.GetTypeCode (to);
 210
 211                                 if (to.IsByRef != from.IsByRef)
 212                                         return false;
 213
 214                                 if (to.IsInterface)
 215                                         return to.IsAssignableFrom (from);
 216
 217                                 switch (fromt) {
 218                                 case TypeCode.Char:
 219                                         switch (tot) {
 220                                         case TypeCode.UInt16:
 221                                         case TypeCode.UInt32:
 222                                         case TypeCode.Int32:
 223                                         case TypeCode.UInt64:
 224                                         case TypeCode.Int64:
 225                                         case TypeCode.Single:
 226                                         case TypeCode.Double:
 227                                                 return true;
 228                                         }
 229                                         return to == typeof (object);
 230                                 case TypeCode.Byte:
 231                                         switch (tot) {
 232                                         case TypeCode.Char:
 233                                         case TypeCode.UInt16:
 234                                         case TypeCode.Int16:
 235                                         case TypeCode.UInt32:
 236                                         case TypeCode.Int32:
 237                                         case TypeCode.UInt64:
 238                                         case TypeCode.Int64:
 239                                         case TypeCode.Single:
 240                                         case TypeCode.Double:
 241                                                 return true;
 242                                         }
 243                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 244                                 case TypeCode.SByte:
 245                                         switch (tot) {
 246                                         case TypeCode.Int16:
 247                                         case TypeCode.Int32:
 248                                         case TypeCode.Int64:
 249                                         case TypeCode.Single:
 250                                         case TypeCode.Double:
 251                                                 return true;
 252                                         }
 253                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 254                                 case TypeCode.UInt16:
 255                                         switch (tot) {
 256                                         case TypeCode.UInt32:
 257                                         case TypeCode.Int32:
 258                                         case TypeCode.UInt64:
 259                                         case TypeCode.Int64:
 260                                         case TypeCode.Single:
 261                                         case TypeCode.Double:
 262                                                 return true;
 263                                         }
 264                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 265                                 case TypeCode.Int16:
 266                                         switch (tot) {
 267                                         case TypeCode.Int32:
 268                                         case TypeCode.Int64:
 269                                         case TypeCode.Single:
 270                                         case TypeCode.Double:
 271                                                 return true;
 272                                         }
 273                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 274                                 case TypeCode.UInt32:
 275                                         switch (tot) {
 276                                         case TypeCode.UInt64:
 277                                         case TypeCode.Int64:
 278                                         case TypeCode.Single:
 279                                         case TypeCode.Double:
 280                                                 return true;
 281                                         }
 282                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 283                                 case TypeCode.Int32:
 284                                         switch (tot) {
 285                                         case TypeCode.Int64:
 286                                         case TypeCode.Single:
 287                                         case TypeCode.Double:
 288                                                 return true;
 289                                         }
 290                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 291                                 case TypeCode.UInt64:
 292                                 case TypeCode.Int64:
 293                                         switch (tot) {
 294                                         case TypeCode.Single:
 295                                         case TypeCode.Double:
 296                                                 return true;
 297                                         }
 298                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 299                                 case TypeCode.Single:
 300                                         return tot == TypeCode.Double || to == typeof (object);
 301                                 default:
 302                                         /* TODO: handle valuetype -> byref */
 303                                         if (to == typeof (object) && from.IsValueType)
 304                                                 return true;
 305
 306                                         return to.IsAssignableFrom (from);
 307                                 }
 308                         }
 309
 310                         private static bool check_arguments (Type[] types, ParameterInfo[] args) {
 311                                 for (int i = 0; i < types.Length; ++i) {
 312                                         if (!check_type (types [i], args [i].ParameterType))
 313                                                 return false;
 314                                 }
 315                                 return true;
 316                         }
 317
 318                         public override MethodBase SelectMethod (BindingFlags bindingAttr, MethodBase[] match, Type[] types, ParameterModifier[] modifiers)
 319                         {
 320                                 MethodBase m;
 321                                 int i, j;
 322
 323                                 if (match == null)
 324                                         throw new ArgumentNullException ("match");
 325
 326                                 /* first look for an exact match... */
 327                                 for (i = 0; i < match.Length; ++i) {
 328                                         m = match [i];
 329                                         ParameterInfo[] args = m.GetParameters ();
 330                                         if (args.Length != types.Length)
 331                                                 continue;
 332                                         for (j = 0; j < types.Length; ++j) {
 333                                                 if (types [j] != args [j].ParameterType)
 334                                                         break;
 335                                         }
 336                                         if (j == types.Length)
 337                                                 return m;
 338                                 }
 339
 340                                 if ((int)(bindingAttr & BindingFlags.ExactBinding) != 0)
 341                                         return null;
 342
 343                                 MethodBase result = null;
 344                                 for (i = 0; i < match.Length; ++i) {
 345                                         m = match [i];
 346                                         ParameterInfo[] args = m.GetParameters ();
 347                                         if (args.Length != types.Length)
 348                                                 continue;
 349                                         if (!check_arguments (types, args))
 350                                                 continue;
 351
 352                                         if (result != null)
 353                                                 result = GetBetterMethod (result, m, types);
 354                                         else
 355                                                 result = m;
 356                                 }
 357
 358                                 return result;
 359                         }
 360
 361                         MethodBase GetBetterMethod (MethodBase m1, MethodBase m2, Type [] types)
 362                         {
 363 #if NET_2_0
 364                                 if (m1.IsGenericMethodDefinition &&
 365                                     !m2.IsGenericMethodDefinition)
 366                                         return m2;
 367                                 if (m2.IsGenericMethodDefinition &&
 368                                     !m1.IsGenericMethodDefinition)
 369                                         return m1;
 370 #endif
 371
 372                                 ParameterInfo [] pl1 = m1.GetParameters ();
 373                                 ParameterInfo [] pl2 = m2.GetParameters ();
 374                                 int prev = 0;
 375                                 for (int i = 0; i < pl1.Length; i++) {
 376                                         int cmp = CompareCloserType (pl1 [i].ParameterType, pl2 [i].ParameterType);
 377                                         if (cmp != 0 && prev != 0 && prev != cmp)
 378                                                 throw new AmbiguousMatchException ();
 379                                         if (cmp != 0)
 380                                                 prev = cmp;
 381                                 }
 382                                 if (prev != 0)
 383                                         return prev > 0 ? m2 : m1;
 384
 385                                 bool va1 = (m1.CallingConvention & CallingConventions.VarArgs) != 0;
 386                                 bool va2 = (m1.CallingConvention & CallingConventions.VarArgs) != 0;
 387                                 if (va1 && !va2)
 388                                         return m2;
 389                                 if (va2 && !va1)
 390                                         return m1;
 391
 392                                 throw new AmbiguousMatchException ();
 393                         }
 394
 395                         int CompareCloserType (Type t1, Type t2)
 396                         {
 397                                 if (t1 == t2)
 398                                         return 0;
 399 #if NET_2_0
 400                                 if (t1.IsGenericParameter && !t2.IsGenericParameter)
 401                                         return 1; // t2
 402                                 if (!t1.IsGenericParameter && t2.IsGenericParameter)
 403                                         return -1; // t1
 404 #endif
 405                                 if (t1.HasElementType && t2.HasElementType)
 406                                         return CompareCloserType (
 407                                                 t1.GetElementType (),
 408                                                 t2.GetElementType ());
 409
 410                                 if (t1.IsSubclassOf (t2))
 411                                         return -1; // t1
 412                                 if (t2.IsSubclassOf (t1))
 413                                         return 1; // t2
 414
 415                                 if (t1.IsInterface && Array.IndexOf (t2.GetInterfaces (), t1) >= 0)
 416                                         return 1; // t2
 417                                 if (t2.IsInterface && Array.IndexOf (t1.GetInterfaces (), t2) >= 0)
 418                                         return -1; // t1
 419
 420                                 // What kind of cases could reach here?
 421                                 return 0;
 422                         }
 423
 424                         public override PropertyInfo SelectProperty (BindingFlags bindingAttr, PropertyInfo[] match, Type returnType, Type[] indexes, ParameterModifier[] modifiers)
 425                         {
 426                                 if (match == null || match.Length == 0)
 427                                         throw new ArgumentException ("No properties provided", "match");
 428
 429                                 bool haveRet = (returnType != null);
 430                                 int idxlen = (indexes != null) ? indexes.Length : -1;
 431                                 PropertyInfo result = null;
 432                                 int i;
 433                                 int best_score = Int32.MaxValue - 1;
 434                                 int fail_score = Int32.MaxValue;
 435                                 int level = 0;
 436
 437                                 for (i = match.Length - 1; i >= 0; i--) {
 438                                         PropertyInfo p = match [i];
 439                                         ParameterInfo[] args = p.GetIndexParameters ();
 440                                         if (idxlen >= 0 && idxlen != args.Length)
 441                                                 continue;
 442
 443                                         if (haveRet && !check_type (p.PropertyType, returnType))
 444                                                 continue;
 445
 446                                         int score = Int32.MaxValue - 1;
 447                                         if (idxlen > 0) {
 448                                                 score = check_arguments_with_score (indexes, args);
 449                                                 if (score == -1)
 450                                                         continue;
 451                                         }
 452
 453                                         int new_level = GetDerivedLevel (p.DeclaringType);
 454                                         if (result != null) {
 455                                                 if (best_score < score)
 456                                                         continue;
 457
 458                                                 if (best_score == score) {
 459                                                         if (level == new_level) {
 460                                                                 // Keep searching. May be there's something
 461                                                                 // better for us.
 462                                                                 fail_score = score;
 463                                                                 continue;
 464                                                         }
 465
 466                                                         if (level > new_level)
 467                                                                 continue;
 468                                                 }
 469                                         }
 470
 471                                         result = p;
 472                                         best_score = score;
 473                                         level = new_level;
 474                                 }
 475
 476                                 if (fail_score <= best_score)
 477                                         throw new AmbiguousMatchException ();
 478
 479                                 return result;
 480                         }
 481
 482                         static int check_arguments_with_score (Type [] types, ParameterInfo [] args)
 483                         {
 484                                 int worst = -1;
 485
 486                                 for (int i = 0; i < types.Length; ++i) {
 487                                         int res = check_type_with_score (types [i], args [i].ParameterType);
 488                                         if (res == -1)
 489                                                 return -1;
 490
 491                                         if (worst < res)
 492                                                 worst = res;
 493                                 }
 494
 495                                 return worst;
 496                         }
 497
 498                         // 0 -> same type or null and !valuetype
 499                         // 1 -> to == Enum
 500                         // 2 -> value type that don't lose data
 501                         // 3 -> to == IsAssignableFrom
 502                         // 4 -> to == object
 503                         static int check_type_with_score (Type from, Type to)
 504                         {
 505                                 if (from == null)
 506                                         return to.IsValueType ? -1 : 0;
 507
 508                                 if (from == to)
 509                                         return 0;
 510
 511                                 if (to == typeof (object))
 512                                         return 4;
 513
 514                                 TypeCode fromt = Type.GetTypeCode (from);
 515                                 TypeCode tot = Type.GetTypeCode (to);
 516
 517                                 switch (fromt) {
 518                                 case TypeCode.Char:
 519                                         switch (tot) {
 520                                         case TypeCode.UInt16:
 521                                                 return 0;
 522
 523                                         case TypeCode.UInt32:
 524                                         case TypeCode.Int32:
 525                                         case TypeCode.UInt64:
 526                                         case TypeCode.Int64:
 527                                         case TypeCode.Single:
 528                                         case TypeCode.Double:
 529                                                 return 2;
 530                                         }
 531                                         return -1;
 532                                 case TypeCode.Byte:
 533                                         switch (tot) {
 534                                         case TypeCode.Char:
 535                                         case TypeCode.UInt16:
 536                                         case TypeCode.Int16:
 537                                         case TypeCode.UInt32:
 538                                         case TypeCode.Int32:
 539                                         case TypeCode.UInt64:
 540                                         case TypeCode.Int64:
 541                                         case TypeCode.Single:
 542                                         case TypeCode.Double:
 543                                                 return 2;
 544                                         }
 545                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 546                                 case TypeCode.SByte:
 547                                         switch (tot) {
 548                                         case TypeCode.Int16:
 549                                         case TypeCode.Int32:
 550                                         case TypeCode.Int64:
 551                                         case TypeCode.Single:
 552                                         case TypeCode.Double:
 553                                                 return 2;
 554                                         }
 555                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 556                                 case TypeCode.UInt16:
 557                                         switch (tot) {
 558                                         case TypeCode.UInt32:
 559                                         case TypeCode.Int32:
 560                                         case TypeCode.UInt64:
 561                                         case TypeCode.Int64:
 562                                         case TypeCode.Single:
 563                                         case TypeCode.Double:
 564                                                 return 2;
 565                                         }
 566                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 567                                 case TypeCode.Int16:
 568                                         switch (tot) {
 569                                         case TypeCode.Int32:
 570                                         case TypeCode.Int64:
 571                                         case TypeCode.Single:
 572                                         case TypeCode.Double:
 573                                                 return 2;
 574                                         }
 575                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 576                                 case TypeCode.UInt32:
 577                                         switch (tot) {
 578                                         case TypeCode.UInt64:
 579                                         case TypeCode.Int64:
 580                                         case TypeCode.Single:
 581                                         case TypeCode.Double:
 582                                                 return 2;
 583                                         }
 584                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 585                                 case TypeCode.Int32:
 586                                         switch (tot) {
 587                                         case TypeCode.Int64:
 588                                         case TypeCode.Single:
 589                                         case TypeCode.Double:
 590                                                 return 2;
 591                                         }
 592                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 593                                 case TypeCode.UInt64:
 594                                 case TypeCode.Int64:
 595                                         switch (tot) {
 596                                         case TypeCode.Single:
 597                                         case TypeCode.Double:
 598                                                 return 2;
 599                                         }
 600                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 601                                 case TypeCode.Single:
 602                                         return tot == TypeCode.Double ? 2 : -1;
 603                                 default:
 604                                         return (to.IsAssignableFrom (from)) ? 3 : -1;
 605                                 }
 606                         }
 607                 }
 608         }
 609 }
 610