mcs/mcs/pending.cs

   1 //
   2 // pending.cs: Pending method implementation
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@gnu.org)
   6 //
   7 // Licensed under the terms of the GNU GPL
   8 //
   9 // (C) 2001, 2002 Ximian, Inc (http://www.ximian.com)
  10 //
  11 //
  12
  13 using System;
  14 using System.Collections;
  15 using System.Reflection;
  16 using System.Reflection.Emit;
  17
  18 namespace Mono.CSharp {
  19
  20         struct TypeAndMethods {
  21                 public Type          type;
  22                 public MethodInfo [] methods;
  23
  24                 //
  25                 // Whether it is optional, this is used to allow the explicit/implicit
  26                 // implementation when a base class already implements an interface.
  27                 //
  28                 // For example:
  29                 //
  30                 // class X : IA { }  class Y : X, IA { IA.Explicit (); }
  31                 //
  32                 public bool          optional;
  33
  34                 // Far from ideal, but we want to avoid creating a copy
  35                 // of methods above.
  36                 public Type [][]     args;
  37
  38                 //This is used to store the modifiers of arguments
  39                 public Parameter.Modifier [][] mods;
  40
  41                 //
  42                 // This flag on the method says `We found a match, but
  43                 // because it was private, we could not use the match
  44                 //
  45                 public bool []       found;
  46
  47                 // If a method is defined here, then we always need to
  48                 // create a proxy for it.  This is used when implementing
  49                 // an interface's indexer with a different IndexerName.
  50                 public MethodInfo [] need_proxy;
  51
  52                 //
  53                 // The name of the indexer (if it exists), precompute set/get, because
  54                 // they would be recomputed many times inside a loop later on.
  55                 //
  56                 public string set_indexer_name;
  57                 public string get_indexer_name;
  58         }
  59
  60         public class PendingImplementation {
  61                 /// <summary>
  62                 ///   The container for this PendingImplementation
  63                 /// </summary>
  64                 TypeContainer container;
  65
  66                 /// <summary>
  67                 ///   This filter is used by FindMembers, and it is used to
  68                 ///   extract only virtual/abstract fields
  69                 /// </summary>
  70                 static MemberFilter virtual_method_filter;
  71
  72                 /// <summary>
  73                 ///   This is the array of TypeAndMethods that describes the pending implementations
  74                 ///   (both interfaces and abstract methods in base class)
  75                 /// </summary>
  76                 TypeAndMethods [] pending_implementations;
  77
  78                 static bool IsVirtualFilter (MemberInfo m, object filterCriteria)
  79                 {
  80                         MethodInfo mi = m as MethodInfo;
  81                         return (mi == null) ? false : mi.IsVirtual;
  82                 }
  83
  84                 /// <summary>
  85                 ///   Inits the virtual_method_filter
  86                 /// </summary>
  87                 static PendingImplementation ()
  88                 {
  89                         virtual_method_filter = new MemberFilter (IsVirtualFilter);
  90                 }
  91
  92                 // <remarks>
  93                 //   Returns a list of the abstract methods that are exposed by all of our
  94                 //   bases that we must implement.  Notice that this `flattens' the
  95                 //   method search space, and takes into account overrides.
  96                 // </remarks>
  97                 static ArrayList GetAbstractMethods (Type t)
  98                 {
  99                         ArrayList list = null;
 100                         bool searching = true;
 101                         Type current_type = t;
 102
 103                         do {
 104                                 MemberList mi;
 105
 106                                 mi = TypeContainer.FindMembers (
 107                                         current_type, MemberTypes.Method,
 108                                         BindingFlags.Public | BindingFlags.NonPublic |
 109                                         BindingFlags.Instance | BindingFlags.DeclaredOnly,
 110                                         virtual_method_filter, null);
 111
 112                                 if (current_type == TypeManager.object_type)
 113                                         searching = false;
 114                                 else {
 115                                         current_type = current_type.BaseType;
 116                                         if (!current_type.IsAbstract)
 117                                                 searching = false;
 118                                 }
 119
 120                                 if (mi.Count == 0)
 121                                         continue;
 122
 123                                 if (mi.Count == 1 && !(mi [0] is MethodBase))
 124                                         searching = false;
 125                                 else
 126                                         list = TypeManager.CopyNewMethods (list, mi);
 127                         } while (searching);
 128
 129                         if (list == null)
 130                                 return null;
 131
 132                         for (int i = 0; i < list.Count; i++){
 133                                 while (list.Count > i && !((MethodInfo) list [i]).IsAbstract)
 134                                         list.RemoveAt (i);
 135                         }
 136
 137                         if (list.Count == 0)
 138                                 return null;
 139
 140                         return list;
 141                 }
 142
 143                 PendingImplementation (TypeContainer container, MissingInterfacesInfo [] missing_ifaces, ArrayList abstract_methods, int total)
 144                 {
 145                         TypeBuilder type_builder = container.TypeBuilder;
 146
 147                         this.container = container;
 148                         pending_implementations = new TypeAndMethods [total];
 149
 150                         int i = 0;
 151                         foreach (MissingInterfacesInfo missing in missing_ifaces){
 152                                 MethodInfo [] mi;
 153                                 Type t = missing.Type;
 154
 155                                 if (!t.IsInterface)
 156                                         continue;
 157
 158                                 if (t is TypeBuilder){
 159                                         TypeContainer iface;
 160
 161                                         iface = TypeManager.LookupInterface (t);
 162
 163                                         mi = iface.GetMethods ();
 164                                 } else
 165                                         mi = t.GetMethods ();
 166
 167                                 int count = mi.Length;
 168                                 pending_implementations [i].type = t;
 169                                 pending_implementations [i].optional = missing.Optional;
 170                                 pending_implementations [i].methods = mi;
 171                                 pending_implementations [i].args = new Type [count][];
 172                                 pending_implementations [i].mods = new Parameter.Modifier [count][];
 173                                 pending_implementations [i].found = new bool [count];
 174                                 pending_implementations [i].need_proxy = new MethodInfo [count];
 175                                 string indexer_name = TypeManager.IndexerPropertyName (t);
 176
 177                                 pending_implementations [i].set_indexer_name = "set_" + indexer_name;
 178                                 pending_implementations [i].get_indexer_name = "get_" + indexer_name;
 179
 180                                 int j = 0;
 181                                 foreach (MethodInfo m in mi){
 182                                         pending_implementations [i].args [j] = Type.EmptyTypes;
 183                                         pending_implementations [i].mods [j] = null;
 184
 185                                         // If there is a previous error, just ignore
 186                                         if (m == null)
 187                                                 continue;
 188
 189                                         ParameterData pd = TypeManager.GetParameterData (m);
 190                                         pending_implementations [i].args [j] = pd.Types;
 191
 192                                         if (pd.Count > 0){
 193                                                 Parameter.Modifier [] pm = new Parameter.Modifier [pd.Count];
 194                                                 for (int k = 0; k < pd.Count; k++)
 195                                                         pm [k] = pd.ParameterModifier (k);
 196                                                 pending_implementations [i].mods [j] = pm;
 197                                         }
 198
 199                                         j++;
 200                                 }
 201                                 i++;
 202                         }
 203
 204                         if (abstract_methods != null){
 205                                 int count = abstract_methods.Count;
 206                                 pending_implementations [i].methods = new MethodInfo [count];
 207                                 pending_implementations [i].need_proxy = new MethodInfo [count];
 208
 209                                 abstract_methods.CopyTo (pending_implementations [i].methods, 0);
 210                                 pending_implementations [i].found = new bool [count];
 211                                 pending_implementations [i].args = new Type [count][];
 212                                 pending_implementations [i].mods = new Parameter.Modifier [count][];
 213                                 pending_implementations [i].type = type_builder;
 214
 215                                 string indexer_name = TypeManager.IndexerPropertyName (type_builder);
 216                                 pending_implementations [i].set_indexer_name = "set_" + indexer_name;
 217                                 pending_implementations [i].get_indexer_name = "get_" + indexer_name;
 218
 219                                 int j = 0;
 220                                 foreach (MemberInfo m in abstract_methods){
 221                                         MethodInfo mi = (MethodInfo) m;
 222
 223                                         ParameterData pd = TypeManager.GetParameterData (mi);
 224                                         Type [] types = pd.Types;
 225
 226                                         pending_implementations [i].args [j] = types;
 227                                         pending_implementations [i].mods [j] = null;
 228                                         if (pd.Count > 0){
 229                                                 Parameter.Modifier [] pm = new Parameter.Modifier [pd.Count];
 230                                                 for (int k = 0; k < pd.Count; k++)
 231                                                         pm [k] = pd.ParameterModifier (k);
 232                                                 pending_implementations [i].mods [j] = pm;
 233                                         }
 234
 235                                         j++;
 236                                 }
 237                         }
 238                 }
 239
 240                 struct MissingInterfacesInfo {
 241                         public Type Type;
 242                         public bool Optional;
 243
 244                         public MissingInterfacesInfo (Type t)
 245                         {
 246                                 Type = t;
 247                                 Optional = false;
 248                         }
 249                 }
 250
 251                 static MissingInterfacesInfo [] EmptyMissingInterfacesInfo = new MissingInterfacesInfo [0];
 252
 253                 static MissingInterfacesInfo [] GetMissingInterfaces (TypeBuilder type_builder)
 254                 {
 255                         //
 256                         // Notice that TypeBuilders will only return the interfaces that the Type
 257                         // is supposed to implement, not all the interfaces that the type implements.
 258                         //
 259                         // Even better -- on MS it returns an empty array, no matter what.
 260                         //
 261                         // Completely broken.  So we do it ourselves!
 262                         //
 263                         Type [] impl = TypeManager.GetExplicitInterfaces (type_builder);
 264
 265                         if (impl == null || impl.Length == 0)
 266                                 return EmptyMissingInterfacesInfo;
 267
 268                         MissingInterfacesInfo [] ret = new MissingInterfacesInfo [impl.Length];
 269
 270                         for (int i = 0; i < impl.Length; i++)
 271                                 ret [i] = new MissingInterfacesInfo (impl [i]);
 272
 273                         // we really should not get here because Object doesnt implement any
 274                         // interfaces. But it could implement something internal, so we have
 275                         // to handle that case.
 276                         if (type_builder.BaseType == null)
 277                                 return ret;
 278
 279                         Type [] base_impls = TypeManager.GetInterfaces (type_builder.BaseType);
 280
 281                         foreach (Type t in base_impls) {
 282                                 for (int i = 0; i < ret.Length; i ++) {
 283                                         if (t == ret [i].Type) {
 284                                                 ret [i].Optional = true;
 285                                                 break;
 286                                         }
 287                                 }
 288                         }
 289                         return ret;
 290                 }
 291
 292                 //
 293                 // Factory method: if there are pending implementation methods, we return a PendingImplementation
 294                 // object, otherwise we return null.
 295                 //
 296                 // Register method implementations are either abstract methods
 297                 // flagged as such on the base class or interface methods
 298                 //
 299                 static public PendingImplementation GetPendingImplementations (TypeContainer container)
 300                 {
 301                         TypeBuilder type_builder = container.TypeBuilder;
 302                         MissingInterfacesInfo [] missing_interfaces;
 303                         Type b = type_builder.BaseType;
 304
 305                         missing_interfaces = GetMissingInterfaces (type_builder);
 306
 307                         //
 308                         // If we are implementing an abstract class, and we are not
 309                         // ourselves abstract, and there are abstract methods (C# allows
 310                         // abstract classes that have no abstract methods), then allocate
 311                         // one slot.
 312                         //
 313                         // We also pre-compute the methods.
 314                         //
 315                         bool implementing_abstract = ((b != null) && b.IsAbstract && !type_builder.IsAbstract);
 316                         ArrayList abstract_methods = null;
 317
 318                         if (implementing_abstract){
 319                                 abstract_methods = GetAbstractMethods (b);
 320
 321                                 if (abstract_methods == null)
 322                                         implementing_abstract = false;
 323                         }
 324
 325                         int total = missing_interfaces.Length +  (implementing_abstract ? 1 : 0);
 326                         if (total == 0)
 327                                 return null;
 328
 329                         return new PendingImplementation (container, missing_interfaces, abstract_methods, total);
 330                 }
 331
 332                 public enum Operation {
 333                         //
 334                         // If you change this, review the whole InterfaceMethod routine as there
 335                         // are a couple of assumptions on these three states
 336                         //
 337                         Lookup, ClearOne, ClearAll
 338                 }
 339
 340                 /// <summary>
 341                 ///   Whether the specified method is an interface method implementation
 342                 /// </summary>
 343                 public MethodInfo IsInterfaceMethod (Type t, string name, Type ret_type, ParameterData args)
 344                 {
 345                         return InterfaceMethod (t, name, ret_type, args, Operation.Lookup, null);
 346                 }
 347
 348                 public MethodInfo IsInterfaceIndexer (Type t, Type ret_type, ParameterData args)
 349                 {
 350                         return InterfaceMethod (t, null, ret_type, args, Operation.Lookup, null);
 351                 }
 352
 353                 public void ImplementMethod (Type t, string name, Type ret_type, ParameterData args, bool clear_one)
 354                 {
 355                         InterfaceMethod (t, name, ret_type, args,
 356                                          clear_one ? Operation.ClearOne : Operation.ClearAll, null);
 357                 }
 358
 359                 public void ImplementIndexer (Type t, MethodInfo mi, Type ret_type, ParameterData args, bool clear_one)
 360                 {
 361                         InterfaceMethod (t, null, ret_type, args,
 362                                          clear_one ? Operation.ClearOne : Operation.ClearAll, mi);
 363                 }
 364
 365                 /// <remarks>
 366                 ///   If a method in Type `t' (or null to look in all interfaces
 367                 ///   and the base abstract class) with name `Name', return type `ret_type' and
 368                 ///   arguments `args' implements an interface, this method will
 369                 ///   return the MethodInfo that this method implements.
 370                 ///
 371                 ///   If `name' is null, we operate solely on the method's signature.  This is for
 372                 ///   instance used when implementing indexers.
 373                 ///
 374                 ///   The `Operation op' controls whether to lookup, clear the pending bit, or clear
 375                 ///   all the methods with the given signature.
 376                 ///
 377                 ///   The `MethodInfo need_proxy' is used when we're implementing an interface's
 378                 ///   indexer in a class.  If the new indexer's IndexerName does not match the one
 379                 ///   that was used in the interface, then we always need to create a proxy for it.
 380                 ///
 381                 /// </remarks>
 382                 public MethodInfo InterfaceMethod (Type t, string name, Type ret_type, ParameterData args,
 383                                                    Operation op, MethodInfo need_proxy)
 384                 {
 385                         int arg_len = args.Count;
 386
 387                         if (pending_implementations == null)
 388                                 return null;
 389
 390                         foreach (TypeAndMethods tm in pending_implementations){
 391                                 if (!(t == null || tm.type == t))
 392                                         continue;
 393
 394                                 int method_count = tm.methods.Length;
 395                                 MethodInfo m;
 396                                 for (int i = 0; i < method_count; i++){
 397                                         m = tm.methods [i];
 398
 399                                         if (m == null)
 400                                                 continue;
 401
 402                                         //
 403                                         // `need_proxy' is not null when we're implementing an
 404                                         // interface indexer and this is Clear(One/All) operation.
 405                                         //
 406                                         // If `name' is null, then we do a match solely based on the
 407                                         // signature and not on the name (this is done in the Lookup
 408                                         // for an interface indexer).
 409                                         //
 410                                         if (name == null){
 411                                                 if (m.Name != tm.get_indexer_name && m.Name != tm.set_indexer_name)
 412                                                         continue;
 413                                         } else if ((need_proxy == null) && (name != m.Name))
 414                                                 continue;
 415
 416                                         if (ret_type != m.ReturnType &&
 417                                             !(ret_type == null && m.ReturnType == TypeManager.void_type) &&
 418                                             !(m.ReturnType == null && ret_type == TypeManager.void_type))
 419                                                 continue;
 420
 421                                         //
 422                                         // Check if we have the same parameters
 423                                         //
 424
 425                                         if (tm.args [i] == null && arg_len != 0)
 426                                                 continue;
 427                                         if (tm.args [i] != null && tm.args [i].Length != arg_len)
 428                                                 continue;
 429
 430                                         int j;
 431
 432                                         for (j = 0; j < arg_len; j++) {
 433                                                 if (tm.args [i][j] != args.ParameterType (j))
 434                                                         break;
 435                                                 if (tm.mods [i][j] == args.ParameterModifier (j))
 436                                                         continue;
 437                                                 // The modifiers are different, but if one of them
 438                                                 // is a PARAMS modifier, and the other isn't, ignore
 439                                                 // the difference.
 440                                                 if (tm.mods [i][j] != Parameter.Modifier.PARAMS &&
 441                                                     args.ParameterModifier (j) != Parameter.Modifier.PARAMS)
 442                                                         break;
 443                                         }
 444                                         if (j != arg_len)
 445                                                 continue;
 446
 447                                         if (op != Operation.Lookup){
 448                                                 // If `t != null', then this is an explicitly interface
 449                                                 // implementation and we can always clear the method.
 450                                                 // `need_proxy' is not null if we're implementing an
 451                                                 // interface indexer.  In this case, we need to create
 452                                                 // a proxy if the implementation's IndexerName doesn't
 453                                                 // match the IndexerName in the interface.
 454                                                 bool name_matches = false;
 455                                                 if (name == m.Name || m.Name == tm.get_indexer_name || m.Name == tm.set_indexer_name)
 456                                                         name_matches = true;
 457
 458                                                 if ((t == null) && (need_proxy != null) && !name_matches)
 459                                                         tm.need_proxy [i] = need_proxy;
 460                                                 else
 461                                                         tm.methods [i] = null;
 462                                         }
 463                                         tm.found [i] = true;
 464
 465                                         //
 466                                         // Lookups and ClearOne return
 467                                         //
 468                                         if (op != Operation.ClearAll)
 469                                                 return m;
 470                                 }
 471
 472                                 // If a specific type was requested, we can stop now.
 473                                 if (tm.type == t)
 474                                         return null;
 475                         }
 476                         return null;
 477                 }
 478
 479                 /// <summary>
 480                 ///   C# allows this kind of scenarios:
 481                 ///   interface I { void M (); }
 482                 ///   class X { public void M (); }
 483                 ///   class Y : X, I { }
 484                 ///
 485                 ///   For that case, we create an explicit implementation function
 486                 ///   I.M in Y.
 487                 /// </summary>
 488                 void DefineProxy (Type iface, MethodInfo base_method, MethodInfo iface_method,
 489                                   Type [] args)
 490                 {
 491                         MethodBuilder proxy;
 492
 493                         string proxy_name = iface.Name + "." + iface_method.Name;
 494
 495                         proxy = container.TypeBuilder.DefineMethod (
 496                                 proxy_name,
 497                                 MethodAttributes.HideBySig |
 498                                 MethodAttributes.NewSlot |
 499                                 MethodAttributes.Virtual,
 500                                 CallingConventions.Standard | CallingConventions.HasThis,
 501                                 base_method.ReturnType, args);
 502
 503                         int top = args.Length;
 504                         ILGenerator ig = proxy.GetILGenerator ();
 505
 506                         for (int i = 0; i <= top; i++)
 507                                 ParameterReference.EmitLdArg (ig, i);
 508
 509                         ig.Emit (OpCodes.Call, base_method);
 510                         ig.Emit (OpCodes.Ret);
 511
 512                         container.TypeBuilder.DefineMethodOverride (proxy, iface_method);
 513                 }
 514
 515                 /// <summary>
 516                 ///   This function tells whether one of our base classes implements
 517                 ///   the given method (which turns out, it is valid to have an interface
 518                 ///   implementation in a base
 519                 /// </summary>
 520                 bool BaseImplements (Type iface_type, MethodInfo mi)
 521                 {
 522                         MethodSignature ms;
 523
 524                         Type [] args = TypeManager.GetParameterData (mi).Types;
 525                         ms = new MethodSignature (mi.Name, mi.ReturnType, args);
 526                         MemberList list = TypeContainer.FindMembers (
 527                                 container.TypeBuilder.BaseType, MemberTypes.Method | MemberTypes.Property,
 528                                 BindingFlags.Public | BindingFlags.Instance,
 529                                 MethodSignature.method_signature_filter, ms);
 530
 531                         if (list.Count == 0)
 532                                 return false;
 533
 534                         if (TypeManager.ImplementsInterface (container.TypeBuilder.BaseType, iface_type))
 535                                 return true;
 536
 537                         //
 538                         // FIXME: We should be creating fewer proxies.  The runtime can handle most cases.
 539                         //        At worst, if we can't avoid creating the proxy, we may need to make the
 540                         //        proxy use Callvirt.
 541                         //
 542                         MethodInfo base_method = (MethodInfo) list [0];
 543
 544                         if (!base_method.IsAbstract && !base_method.IsVirtual)
 545                                 DefineProxy (iface_type, base_method, mi, args);
 546
 547                         return true;
 548                 }
 549
 550                 /// <summary>
 551                 ///   Verifies that any pending abstract methods or interface methods
 552                 ///   were implemented.
 553                 /// </summary>
 554                 public bool VerifyPendingMethods ()
 555                 {
 556                         int top = pending_implementations.Length;
 557                         bool errors = false;
 558                         int i;
 559
 560                         for (i = 0; i < top; i++){
 561                                 Type type = pending_implementations [i].type;
 562                                 int j = 0;
 563
 564                                 foreach (MethodInfo mi in pending_implementations [i].methods){
 565                                         if (mi == null)
 566                                                 continue;
 567
 568                                         if (type.IsInterface){
 569                                                 MethodInfo need_proxy =
 570                                                         pending_implementations [i].need_proxy [j];
 571
 572                                                 if (need_proxy != null) {
 573                                                         Type [] args = TypeManager.GetParameterData (mi).Types;
 574                                                         DefineProxy (type, need_proxy, mi, args);
 575                                                         continue;
 576                                                 }
 577
 578                                                 if (BaseImplements (type, mi))
 579                                                         continue;
 580
 581                                                 if (pending_implementations [i].optional)
 582                                                         continue;
 583
 584                                                 Report.SymbolRelatedToPreviousError (mi);
 585                                                 if (pending_implementations [i].found [j]) {
 586                                                         if (mi.IsSpecialName) {
 587                                                                 string name = TypeManager.CSharpName (mi.DeclaringType) + '.' + mi.Name.Substring (4);
 588                                                                 Report.Error (551, container.Location, "Explicit interface implementation `{0}.{1}' is missing accessor `{2}'",
 589                                                                         container.GetSignatureForError (), name, TypeManager.CSharpSignature (mi, true));
 590                                                         } else {
 591                                                                 string[] methodLabel = TypeManager.CSharpSignature (mi).Split ('.');
 592                                                                 Report.Error (536, container.Location,
 593                                                                         "`{0}' does not implement interface member `{1}'. `{2}.{3}' " +
 594                                                                         "is either static, not public, or has the wrong return type",
 595                                                                         container.Name, TypeManager.CSharpSignature (mi),
 596                                                                         container.Name, methodLabel[methodLabel.Length - 1]);
 597                                                         }
 598                                                 }
 599                                                 else {
 600                                                         Report.Error (535, container.Location, "`{0}' does not implement interface member `{1}'",
 601                                                                 container.GetSignatureForError (), TypeManager.CSharpSignature (mi));
 602                                                 }
 603                                         } else {
 604                                                 Report.Error (534, container.Location, "`{0}' does not implement inherited abstract member `{1}'",
 605                                                         container.GetSignatureForError (), TypeManager.CSharpSignature (mi, true));
 606                                         }
 607                                         errors = true;
 608                                         j++;
 609                                 }
 610                         }
 611                         return errors;
 612                 }
 613         } /* end of class */
 614 }