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                                 return selected;
 145                         }
 146
 147                         static bool IsArrayAssignable (Type object_type, Type target_type)
 148                         {
 149                                 if (object_type.IsArray && target_type.IsArray)
 150                                         return IsArrayAssignable (object_type.GetElementType (), target_type.GetElementType ());
 151
 152                                 if (target_type.IsAssignableFrom (object_type))
 153                                         return true;
 154
 155                                 return false;
 156                         }
 157
 158                         public override object ChangeType (object value, Type type, CultureInfo culture)
 159                         {
 160                                 if (value == null)
 161                                         return null;
 162                                 Type vtype = value.GetType ();
 163                                 if (type.IsByRef)
 164                                         type = type.GetElementType ();
 165                                 if (vtype == type || type.IsInstanceOfType (value))
 166                                         return value;
 167                                 if (vtype.IsArray && type.IsArray){
 168                                         if (IsArrayAssignable (vtype.GetElementType (), type.GetElementType ()))
 169                                                 return value;
 170                                 }
 171
 172                                 if (check_type (vtype, type))
 173                                         return Convert.ChangeType (value, type);
 174                                 return null;
 175                         }
 176
 177                         [MonoTODO]
 178                         public override void ReorderArgumentArray (ref object[] args, object state)
 179                         {
 180                                 //do nothing until we support named arguments
 181                                 //throw new NotImplementedException ();
 182                         }
 183
 184                         private static bool check_type (Type from, Type to) {
 185                                 if (from == to)
 186                                         return true;
 187
 188                                 if (from == null)
 189                                         return true;
 190
 191                                 TypeCode fromt = Type.GetTypeCode (from);
 192                                 TypeCode tot = Type.GetTypeCode (to);
 193
 194                                 if (to.IsByRef != from.IsByRef)
 195                                         return false;
 196
 197                                 switch (fromt) {
 198                                 case TypeCode.Char:
 199                                         switch (tot) {
 200                                         case TypeCode.UInt16:
 201                                         case TypeCode.UInt32:
 202                                         case TypeCode.Int32:
 203                                         case TypeCode.UInt64:
 204                                         case TypeCode.Int64:
 205                                         case TypeCode.Single:
 206                                         case TypeCode.Double:
 207                                                 return true;
 208                                         }
 209                                         return to == typeof (object);
 210                                 case TypeCode.Byte:
 211                                         switch (tot) {
 212                                         case TypeCode.Char:
 213                                         case TypeCode.UInt16:
 214                                         case TypeCode.Int16:
 215                                         case TypeCode.UInt32:
 216                                         case TypeCode.Int32:
 217                                         case TypeCode.UInt64:
 218                                         case TypeCode.Int64:
 219                                         case TypeCode.Single:
 220                                         case TypeCode.Double:
 221                                                 return true;
 222                                         }
 223                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 224                                 case TypeCode.SByte:
 225                                         switch (tot) {
 226                                         case TypeCode.Int16:
 227                                         case TypeCode.Int32:
 228                                         case TypeCode.Int64:
 229                                         case TypeCode.Single:
 230                                         case TypeCode.Double:
 231                                                 return true;
 232                                         }
 233                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 234                                 case TypeCode.UInt16:
 235                                         switch (tot) {
 236                                         case TypeCode.UInt32:
 237                                         case TypeCode.Int32:
 238                                         case TypeCode.UInt64:
 239                                         case TypeCode.Int64:
 240                                         case TypeCode.Single:
 241                                         case TypeCode.Double:
 242                                                 return true;
 243                                         }
 244                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 245                                 case TypeCode.Int16:
 246                                         switch (tot) {
 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.UInt32:
 255                                         switch (tot) {
 256                                         case TypeCode.UInt64:
 257                                         case TypeCode.Int64:
 258                                         case TypeCode.Single:
 259                                         case TypeCode.Double:
 260                                                 return true;
 261                                         }
 262                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 263                                 case TypeCode.Int32:
 264                                         switch (tot) {
 265                                         case TypeCode.Int64:
 266                                         case TypeCode.Single:
 267                                         case TypeCode.Double:
 268                                                 return true;
 269                                         }
 270                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 271                                 case TypeCode.UInt64:
 272                                 case TypeCode.Int64:
 273                                         switch (tot) {
 274                                         case TypeCode.Single:
 275                                         case TypeCode.Double:
 276                                                 return true;
 277                                         }
 278                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 279                                 case TypeCode.Single:
 280                                         return tot == TypeCode.Double || to == typeof (object);
 281                                 default:
 282                                         /* TODO: handle valuetype -> byref */
 283                                         if (to == typeof (object) && from.IsValueType)
 284                                                 return true;
 285
 286                                         return to.IsAssignableFrom (from);
 287                                 }
 288                         }
 289
 290                         private static bool check_arguments (Type[] types, ParameterInfo[] args) {
 291                                 for (int i = 0; i < types.Length; ++i) {
 292                                         if (!check_type (types [i], args [i].ParameterType))
 293                                                 return false;
 294                                 }
 295                                 return true;
 296                         }
 297
 298                         public override MethodBase SelectMethod (BindingFlags bindingAttr, MethodBase[] match, Type[] types, ParameterModifier[] modifiers)
 299                         {
 300                                 MethodBase m;
 301                                 int i, j;
 302
 303                                 if (match == null)
 304                                         throw new ArgumentNullException ("match");
 305
 306                                 /* first look for an exact match... */
 307                                 for (i = 0; i < match.Length; ++i) {
 308                                         m = match [i];
 309                                         ParameterInfo[] args = m.GetParameters ();
 310                                         if (args.Length != types.Length)
 311                                                 continue;
 312                                         for (j = 0; j < types.Length; ++j) {
 313                                                 if (types [j] != args [j].ParameterType)
 314                                                         break;
 315                                         }
 316                                         if (j == types.Length)
 317                                                 return m;
 318                                 }
 319
 320                                 MethodBase result = null;
 321                                 for (i = 0; i < match.Length; ++i) {
 322                                         m = match [i];
 323                                         ParameterInfo[] args = m.GetParameters ();
 324                                         if (args.Length != types.Length)
 325                                                 continue;
 326                                         if (!check_arguments (types, args))
 327                                                 continue;
 328
 329                                         if (result != null)
 330                                                 throw new AmbiguousMatchException ();
 331
 332                                         result = m;
 333                                 }
 334
 335                                 return result;
 336                         }
 337
 338                         public override PropertyInfo SelectProperty (BindingFlags bindingAttr, PropertyInfo[] match, Type returnType, Type[] indexes, ParameterModifier[] modifiers)
 339                         {
 340                                 if (match == null || match.Length == 0)
 341                                         throw new ArgumentException ("No properties provided", "match");
 342
 343                                 bool haveRet = (returnType != null);
 344                                 int idxlen = (indexes != null) ? indexes.Length : -1;
 345                                 PropertyInfo result = null;
 346                                 int i;
 347                                 int best_score = Int32.MaxValue - 1;
 348                                 int fail_score = Int32.MaxValue;
 349                                 int level = 0;
 350
 351                                 for (i = match.Length - 1; i >= 0; i--) {
 352                                         PropertyInfo p = match [i];
 353                                         ParameterInfo[] args = p.GetIndexParameters ();
 354                                         if (idxlen >= 0 && idxlen != args.Length)
 355                                                 continue;
 356
 357                                         if (haveRet && !check_type (p.PropertyType, returnType))
 358                                                 continue;
 359
 360                                         int score = Int32.MaxValue - 1;
 361                                         if (idxlen > 0) {
 362                                                 score = check_arguments_with_score (indexes, args);
 363                                                 if (score == -1)
 364                                                         continue;
 365                                         }
 366
 367                                         int new_level = GetDerivedLevel (p.DeclaringType);
 368                                         if (result != null) {
 369                                                 if (best_score < score)
 370                                                         continue;
 371
 372                                                 if (best_score == score) {
 373                                                         if (level == new_level) {
 374                                                                 // Keep searching. May be there's something
 375                                                                 // better for us.
 376                                                                 fail_score = score;
 377                                                                 continue;
 378                                                         }
 379
 380                                                         if (level > new_level)
 381                                                                 continue;
 382                                                 }
 383                                         }
 384
 385                                         result = p;
 386                                         best_score = score;
 387                                         level = new_level;
 388                                 }
 389
 390                                 if (fail_score <= best_score)
 391                                         throw new AmbiguousMatchException ();
 392
 393                                 return result;
 394                         }
 395
 396                         static int check_arguments_with_score (Type [] types, ParameterInfo [] args)
 397                         {
 398                                 int worst = -1;
 399
 400                                 for (int i = 0; i < types.Length; ++i) {
 401                                         int res = check_type_with_score (types [i], args [i].ParameterType);
 402                                         if (res == -1)
 403                                                 return -1;
 404
 405                                         if (worst < res)
 406                                                 worst = res;
 407                                 }
 408
 409                                 return worst;
 410                         }
 411
 412                         // 0 -> same type or null and !valuetype
 413                         // 1 -> to == Enum
 414                         // 2 -> value type that don't lose data
 415                         // 3 -> to == IsAssignableFrom
 416                         // 4 -> to == object
 417                         static int check_type_with_score (Type from, Type to)
 418                         {
 419                                 if (from == null)
 420                                         return to.IsValueType ? -1 : 0;
 421
 422                                 if (from == to)
 423                                         return 0;
 424
 425                                 if (to == typeof (object))
 426                                         return 4;
 427
 428                                 TypeCode fromt = Type.GetTypeCode (from);
 429                                 TypeCode tot = Type.GetTypeCode (to);
 430
 431                                 switch (fromt) {
 432                                 case TypeCode.Char:
 433                                         switch (tot) {
 434                                         case TypeCode.UInt16:
 435                                                 return 0;
 436
 437                                         case TypeCode.UInt32:
 438                                         case TypeCode.Int32:
 439                                         case TypeCode.UInt64:
 440                                         case TypeCode.Int64:
 441                                         case TypeCode.Single:
 442                                         case TypeCode.Double:
 443                                                 return 2;
 444                                         }
 445                                         return -1;
 446                                 case TypeCode.Byte:
 447                                         switch (tot) {
 448                                         case TypeCode.Char:
 449                                         case TypeCode.UInt16:
 450                                         case TypeCode.Int16:
 451                                         case TypeCode.UInt32:
 452                                         case TypeCode.Int32:
 453                                         case TypeCode.UInt64:
 454                                         case TypeCode.Int64:
 455                                         case TypeCode.Single:
 456                                         case TypeCode.Double:
 457                                                 return 2;
 458                                         }
 459                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 460                                 case TypeCode.SByte:
 461                                         switch (tot) {
 462                                         case TypeCode.Int16:
 463                                         case TypeCode.Int32:
 464                                         case TypeCode.Int64:
 465                                         case TypeCode.Single:
 466                                         case TypeCode.Double:
 467                                                 return 2;
 468                                         }
 469                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 470                                 case TypeCode.UInt16:
 471                                         switch (tot) {
 472                                         case TypeCode.UInt32:
 473                                         case TypeCode.Int32:
 474                                         case TypeCode.UInt64:
 475                                         case TypeCode.Int64:
 476                                         case TypeCode.Single:
 477                                         case TypeCode.Double:
 478                                                 return 2;
 479                                         }
 480                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 481                                 case TypeCode.Int16:
 482                                         switch (tot) {
 483                                         case TypeCode.Int32:
 484                                         case TypeCode.Int64:
 485                                         case TypeCode.Single:
 486                                         case TypeCode.Double:
 487                                                 return 2;
 488                                         }
 489                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 490                                 case TypeCode.UInt32:
 491                                         switch (tot) {
 492                                         case TypeCode.UInt64:
 493                                         case TypeCode.Int64:
 494                                         case TypeCode.Single:
 495                                         case TypeCode.Double:
 496                                                 return 2;
 497                                         }
 498                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 499                                 case TypeCode.Int32:
 500                                         switch (tot) {
 501                                         case TypeCode.Int64:
 502                                         case TypeCode.Single:
 503                                         case TypeCode.Double:
 504                                                 return 2;
 505                                         }
 506                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 507                                 case TypeCode.UInt64:
 508                                 case TypeCode.Int64:
 509                                         switch (tot) {
 510                                         case TypeCode.Single:
 511                                         case TypeCode.Double:
 512                                                 return 2;
 513                                         }
 514                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 515                                 case TypeCode.Single:
 516                                         return tot == TypeCode.Double ? 2 : -1;
 517                                 default:
 518                                         return (to.IsAssignableFrom (from)) ? 3 : -1;
 519                                 }
 520                         }
 521                 }
 522         }
 523 }
 524