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

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