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 parent 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                 //
  39                 // This flag on the method says `We found a match, but
  40                 // because it was private, we could not use the match
  41                 //
  42                 public bool []       found;
  43
  44                 // If a method is defined here, then we always need to
  45                 // create a proxy for it.  This is used when implementing
  46                 // an interface's indexer with a different IndexerName.
  47                 public MethodInfo [] need_proxy;
  48
  49                 //
  50                 // The name of the indexer (if it exists), precompute set/get, because
  51                 // they would be recomputed many times inside a loop later on.
  52                 //
  53                 public string set_indexer_name;
  54                 public string get_indexer_name;
  55         }
  56
  57         public class PendingImplementation {
  58                 /// <summary>
  59                 ///   The container for this PendingImplementation
  60                 /// </summary>
  61                 TypeContainer container;
  62
  63                 /// <summary>
  64                 ///   This filter is used by FindMembers, and it is used to
  65                 ///   extract only virtual/abstract fields
  66                 /// </summary>
  67                 static MemberFilter virtual_method_filter;
  68
  69                 /// <summary>
  70                 ///   This is the array of TypeAndMethods that describes the pending implementations
  71                 ///   (both interfaces and abstract methods in parent class)
  72                 /// </summary>
  73                 TypeAndMethods [] pending_implementations;
  74
  75                 static bool IsVirtualFilter (MemberInfo m, object filterCriteria)
  76                 {
  77                         MethodInfo mi = m as MethodInfo;
  78                         return (mi == null) ? false : mi.IsVirtual;
  79                 }
  80
  81                 /// <summary>
  82                 ///   Inits the virtual_method_filter
  83                 /// </summary>
  84                 static PendingImplementation ()
  85                 {
  86                         virtual_method_filter = new MemberFilter (IsVirtualFilter);
  87                 }
  88
  89                 // <remarks>
  90                 //   Returns a list of the abstract methods that are exposed by all of our
  91                 //   parents that we must implement.  Notice that this `flattens' the
  92                 //   method search space, and takes into account overrides.
  93                 // </remarks>
  94                 static ArrayList GetAbstractMethods (Type t)
  95                 {
  96                         ArrayList list = null;
  97                         bool searching = true;
  98                         Type current_type = t;
  99
 100                         do {
 101                                 MemberList mi;
 102
 103                                 mi = TypeContainer.FindMembers (
 104                                         current_type, MemberTypes.Method,
 105                                         BindingFlags.Public | BindingFlags.Instance |
 106                                         BindingFlags.DeclaredOnly,
 107                                         virtual_method_filter, null);
 108
 109                                 if (current_type == TypeManager.object_type)
 110                                         searching = false;
 111                                 else {
 112                                         current_type = current_type.BaseType;
 113                                         if (!current_type.IsAbstract)
 114                                                 searching = false;
 115                                 }
 116
 117                                 if (mi.Count == 0)
 118                                         continue;
 119
 120                                 if (mi.Count == 1 && !(mi [0] is MethodBase))
 121                                         searching = false;
 122                                 else
 123                                         list = TypeManager.CopyNewMethods (list, mi);
 124                         } while (searching);
 125
 126                         if (list == null)
 127                                 return null;
 128
 129                         for (int i = 0; i < list.Count; i++){
 130                                 while (list.Count > i && !((MethodInfo) list [i]).IsAbstract)
 131                                         list.RemoveAt (i);
 132                         }
 133
 134                         if (list.Count == 0)
 135                                 return null;
 136
 137                         return list;
 138                 }
 139
 140                 PendingImplementation (TypeContainer container, MissingInterfacesInfo [] missing_ifaces, ArrayList abstract_methods, int total)
 141                 {
 142                         TypeBuilder type_builder = container.TypeBuilder;
 143
 144                         this.container = container;
 145                         pending_implementations = new TypeAndMethods [total];
 146
 147                         int i = 0;
 148                         foreach (MissingInterfacesInfo missing in missing_ifaces){
 149                                 MethodInfo [] mi;
 150                                 Type t = missing.Type;
 151
 152                                 if (t is TypeBuilder){
 153                                         TypeContainer iface;
 154
 155                                         iface = TypeManager.LookupInterface (t);
 156
 157                                         mi = iface.GetMethods ();
 158                                 } else
 159                                         mi = t.GetMethods ();
 160
 161                                 int count = mi.Length;
 162                                 pending_implementations [i].type = t;
 163                                 pending_implementations [i].optional = missing.Optional;
 164                                 pending_implementations [i].methods = mi;
 165                                 pending_implementations [i].args = new Type [count][];
 166                                 pending_implementations [i].found = new bool [count];
 167                                 pending_implementations [i].need_proxy = new MethodInfo [count];
 168                                 string indexer_name = TypeManager.IndexerPropertyName (t);
 169
 170                                 pending_implementations [i].set_indexer_name = "set_" + indexer_name;
 171                                 pending_implementations [i].get_indexer_name = "get_" + indexer_name;
 172
 173                                 int j = 0;
 174                                 foreach (MethodInfo m in mi){
 175                                         Type [] types = TypeManager.GetArgumentTypes (m);
 176
 177                                         pending_implementations [i].args [j] = types;
 178                                         j++;
 179                                 }
 180                                 i++;
 181                         }
 182
 183                         if (abstract_methods != null){
 184                                 int count = abstract_methods.Count;
 185                                 pending_implementations [i].methods = new MethodInfo [count];
 186                                 pending_implementations [i].need_proxy = new MethodInfo [count];
 187
 188                                 abstract_methods.CopyTo (pending_implementations [i].methods, 0);
 189                                 pending_implementations [i].found = new bool [count];
 190                                 pending_implementations [i].args = new Type [count][];
 191                                 pending_implementations [i].type = type_builder;
 192
 193                                 string indexer_name = TypeManager.IndexerPropertyName (type_builder);
 194                                 pending_implementations [i].set_indexer_name = "set_" + indexer_name;
 195                                 pending_implementations [i].get_indexer_name = "get_" + indexer_name;
 196
 197                                 int j = 0;
 198                                 foreach (MemberInfo m in abstract_methods){
 199                                         MethodInfo mi = (MethodInfo) m;
 200
 201                                         Type [] types = TypeManager.GetArgumentTypes (mi);
 202
 203                                         pending_implementations [i].args [j] = types;
 204                                         j++;
 205                                 }
 206                         }
 207                 }
 208
 209                 struct MissingInterfacesInfo {
 210                         public Type Type;
 211                         public bool Optional;
 212
 213                         public MissingInterfacesInfo (Type t)
 214                         {
 215                                 Type = t;
 216                                 Optional = false;
 217                         }
 218                 }
 219
 220                 static MissingInterfacesInfo [] EmptyMissingInterfacesInfo = new MissingInterfacesInfo [0];
 221
 222                 static MissingInterfacesInfo [] GetMissingInterfaces (TypeBuilder type_builder)
 223                 {
 224                         //
 225                         // Notice that TypeBuilders will only return the interfaces that the Type
 226                         // is supposed to implement, not all the interfaces that the type implements.
 227                         //
 228                         // Even better -- on MS it returns an empty array, no matter what.
 229                         //
 230                         // Completely broken.  So we do it ourselves!
 231                         //
 232                         TypeExpr [] impl = TypeManager.GetExplicitInterfaces (type_builder);
 233
 234                         if (impl == null || impl.Length == 0)
 235                                 return EmptyMissingInterfacesInfo;
 236
 237                         MissingInterfacesInfo [] ret = new MissingInterfacesInfo [impl.Length];
 238
 239                         for (int i = 0; i < impl.Length; i++)
 240                                 ret [i] = new MissingInterfacesInfo (impl [i].Type);
 241
 242                         // we really should not get here because Object doesnt implement any
 243                         // interfaces. But it could implement something internal, so we have
 244                         // to handle that case.
 245                         if (type_builder.BaseType == null)
 246                                 return ret;
 247
 248                         TypeExpr [] parent_impls = TypeManager.GetInterfaces (type_builder.BaseType);
 249
 250                         foreach (TypeExpr te in parent_impls) {
 251                                 Type t = te.Type;
 252
 253                                 for (int i = 0; i < ret.Length; i ++) {
 254                                         if (t == ret [i].Type) {
 255                                                 ret [i].Optional = true;
 256                                                 break;
 257                                         }
 258                                 }
 259                         }
 260                         return ret;
 261                 }
 262
 263                 //
 264                 // Factory method: if there are pending implementation methods, we return a PendingImplementation
 265                 // object, otherwise we return null.
 266                 //
 267                 // Register method implementations are either abstract methods
 268                 // flagged as such on the base class or interface methods
 269                 //
 270                 static public PendingImplementation GetPendingImplementations (TypeContainer container)
 271                 {
 272                         TypeBuilder type_builder = container.TypeBuilder;
 273                         MissingInterfacesInfo [] missing_interfaces;
 274                         Type b = type_builder.BaseType;
 275
 276                         missing_interfaces = GetMissingInterfaces (type_builder);
 277
 278                         //
 279                         // If we are implementing an abstract class, and we are not
 280                         // ourselves abstract, and there are abstract methods (C# allows
 281                         // abstract classes that have no abstract methods), then allocate
 282                         // one slot.
 283                         //
 284                         // We also pre-compute the methods.
 285                         //
 286                         bool implementing_abstract = ((b != null) && b.IsAbstract && !type_builder.IsAbstract);
 287                         ArrayList abstract_methods = null;
 288
 289                         if (implementing_abstract){
 290                                 abstract_methods = GetAbstractMethods (b);
 291
 292                                 if (abstract_methods == null)
 293                                         implementing_abstract = false;
 294                         }
 295
 296                         int total = missing_interfaces.Length +  (implementing_abstract ? 1 : 0);
 297                         if (total == 0)
 298                                 return null;
 299
 300                         return new PendingImplementation (container, missing_interfaces, abstract_methods, total);
 301                 }
 302
 303                 public enum Operation {
 304                         //
 305                         // If you change this, review the whole InterfaceMethod routine as there
 306                         // are a couple of assumptions on these three states
 307                         //
 308                         Lookup, ClearOne, ClearAll
 309                 }
 310
 311                 /// <summary>
 312                 ///   Whether the specified method is an interface method implementation
 313                 /// </summary>
 314                 public MethodInfo IsInterfaceMethod (Type t, string name, Type ret_type, Type [] args)
 315                 {
 316                         return InterfaceMethod (t, name, ret_type, args, Operation.Lookup, null);
 317                 }
 318
 319                 public MethodInfo IsInterfaceIndexer (Type t, Type ret_type, Type [] args)
 320                 {
 321                         return InterfaceMethod (t, null, ret_type, args, Operation.Lookup, null);
 322                 }
 323
 324                 public void ImplementMethod (Type t, string name, Type ret_type, Type [] args, bool clear_one)
 325                 {
 326                         InterfaceMethod (t, name, ret_type, args,
 327                                          clear_one ? Operation.ClearOne : Operation.ClearAll, null);
 328                 }
 329
 330                 public void ImplementIndexer (Type t, MethodInfo mi, Type ret_type, Type [] args, bool clear_one)
 331                 {
 332                         InterfaceMethod (t, null, ret_type, args,
 333                                          clear_one ? Operation.ClearOne : Operation.ClearAll, mi);
 334                 }
 335
 336                 /// <remarks>
 337                 ///   If a method in Type `t' (or null to look in all interfaces
 338                 ///   and the base abstract class) with name `Name', return type `ret_type' and
 339                 ///   arguments `args' implements an interface, this method will
 340                 ///   return the MethodInfo that this method implements.
 341                 ///
 342                 ///   If `name' is null, we operate solely on the method's signature.  This is for
 343                 ///   instance used when implementing indexers.
 344                 ///
 345                 ///   The `Operation op' controls whether to lookup, clear the pending bit, or clear
 346                 ///   all the methods with the given signature.
 347                 ///
 348                 ///   The `MethodInfo need_proxy' is used when we're implementing an interface's
 349                 ///   indexer in a class.  If the new indexer's IndexerName does not match the one
 350                 ///   that was used in the interface, then we always need to create a proxy for it.
 351                 ///
 352                 /// </remarks>
 353                 public MethodInfo InterfaceMethod (Type t, string name, Type ret_type, Type [] args,
 354                                                    Operation op, MethodInfo need_proxy)
 355                 {
 356                         int arg_len = args.Length;
 357
 358                         if (pending_implementations == null)
 359                                 return null;
 360
 361                         foreach (TypeAndMethods tm in pending_implementations){
 362                                 if (!(t == null || tm.type == t))
 363                                         continue;
 364
 365                                 int method_count = tm.methods.Length;
 366                                 MethodInfo m;
 367                                 for (int i = 0; i < method_count; i++){
 368                                         m = tm.methods [i];
 369
 370                                         if (m == null)
 371                                                 continue;
 372
 373                                         //
 374                                         // `need_proxy' is not null when we're implementing an
 375                                         // interface indexer and this is Clear(One/All) operation.
 376                                         //
 377                                         // If `name' is null, then we do a match solely based on the
 378                                         // signature and not on the name (this is done in the Lookup
 379                                         // for an interface indexer).
 380                                         //
 381                                         if (name == null){
 382                                                 if (m.Name != tm.get_indexer_name && m.Name != tm.set_indexer_name)
 383                                                         continue;
 384                                         } else if ((need_proxy == null) && (name != m.Name))
 385                                                 continue;
 386
 387                                         if (ret_type != m.ReturnType){
 388                                                 if (!((ret_type == null && m.ReturnType == TypeManager.void_type) ||
 389                                                       (m.ReturnType == null && ret_type == TypeManager.void_type)))
 390                                                         continue;
 391                                         }
 392
 393                                         //
 394                                         // Check if we have the same parameters
 395                                         //
 396                                         if (tm.args [i].Length != arg_len)
 397                                                 continue;
 398
 399                                         int j, top = args.Length;
 400                                         bool fail = false;
 401
 402                                         for (j = 0; j < top; j++){
 403                                                 if (tm.args [i][j] != args[j]){
 404                                                         fail = true;
 405                                                         break;
 406                                                 }
 407                                         }
 408                                         if (fail)
 409                                                 continue;
 410
 411                                         if (op != Operation.Lookup){
 412                                                 // If `t != null', then this is an explicitly interface
 413                                                 // implementation and we can always clear the method.
 414                                                 // `need_proxy' is not null if we're implementing an
 415                                                 // interface indexer.  In this case, we need to create
 416                                                 // a proxy if the implementation's IndexerName doesn't
 417                                                 // match the IndexerName in the interface.
 418                                                 bool name_matches = false;
 419                                                 if (name == m.Name || m.Name == tm.get_indexer_name || m.Name == tm.set_indexer_name)
 420                                                         name_matches = true;
 421
 422                                                 if ((t == null) && (need_proxy != null) && !name_matches)
 423                                                         tm.need_proxy [i] = need_proxy;
 424                                                 else
 425                                                         tm.methods [i] = null;
 426                                         }
 427                                         tm.found [i] = true;
 428
 429                                         //
 430                                         // Lookups and ClearOne return
 431                                         //
 432                                         if (op != Operation.ClearAll)
 433                                                 return m;
 434                                 }
 435
 436                                 // If a specific type was requested, we can stop now.
 437                                 if (tm.type == t)
 438                                         return null;
 439                         }
 440                         return null;
 441                 }
 442
 443                 /// <summary>
 444                 ///   C# allows this kind of scenarios:
 445                 ///   interface I { void M (); }
 446                 ///   class X { public void M (); }
 447                 ///   class Y : X, I { }
 448                 ///
 449                 ///   For that case, we create an explicit implementation function
 450                 ///   I.M in Y.
 451                 /// </summary>
 452                 void DefineProxy (Type iface, MethodInfo parent_method, MethodInfo iface_method,
 453                                   Type [] args)
 454                 {
 455                         MethodBuilder proxy;
 456
 457                         string proxy_name = iface.Name + "." + iface_method.Name;
 458
 459                         proxy = container.TypeBuilder.DefineMethod (
 460                                 proxy_name,
 461                                 MethodAttributes.HideBySig |
 462                                 MethodAttributes.NewSlot |
 463                                 MethodAttributes.Virtual,
 464                                 CallingConventions.Standard | CallingConventions.HasThis,
 465                                 parent_method.ReturnType, args);
 466
 467                         int top = args.Length;
 468                         ILGenerator ig = proxy.GetILGenerator ();
 469
 470                         ig.Emit (OpCodes.Ldarg_0);
 471                         for (int i = 0; i < top; i++){
 472                                 switch (i){
 473                                 case 0:
 474                                         ig.Emit (OpCodes.Ldarg_1); break;
 475                                 case 1:
 476                                         ig.Emit (OpCodes.Ldarg_2); break;
 477                                 case 2:
 478                                         ig.Emit (OpCodes.Ldarg_3); break;
 479                                 default:
 480                                         ig.Emit (OpCodes.Ldarg, i - 1); break;
 481                                 }
 482                         }
 483                         ig.Emit (OpCodes.Call, parent_method);
 484                         ig.Emit (OpCodes.Ret);
 485
 486                         container.TypeBuilder.DefineMethodOverride (proxy, iface_method);
 487                 }
 488
 489                 /// <summary>
 490                 ///   This function tells whether one of our parent classes implements
 491                 ///   the given method (which turns out, it is valid to have an interface
 492                 ///   implementation in a parent
 493                 /// </summary>
 494                 bool ParentImplements (Type iface_type, MethodInfo mi)
 495                 {
 496                         MethodSignature ms;
 497
 498                         Type [] args = TypeManager.GetArgumentTypes (mi);
 499                         ms = new MethodSignature (mi.Name, mi.ReturnType, args);
 500                         MemberList list = TypeContainer.FindMembers (
 501                                 container.TypeBuilder.BaseType, MemberTypes.Method | MemberTypes.Property,
 502                                 BindingFlags.Public | BindingFlags.Instance,
 503                                 MethodSignature.method_signature_filter, ms);
 504
 505                         if (list.Count == 0)
 506                                 return false;
 507
 508                         MethodInfo parent = (MethodInfo) list [0];
 509                         if (!parent.IsAbstract)
 510                                 DefineProxy (iface_type, parent, mi, args);
 511                         return true;
 512                 }
 513
 514                 /// <summary>
 515                 ///   Verifies that any pending abstract methods or interface methods
 516                 ///   were implemented.
 517                 /// </summary>
 518                 public bool VerifyPendingMethods ()
 519                 {
 520                         int top = pending_implementations.Length;
 521                         bool errors = false;
 522                         int i;
 523
 524                         for (i = 0; i < top; i++){
 525                                 Type type = pending_implementations [i].type;
 526                                 int j = 0;
 527
 528                                 foreach (MethodInfo mi in pending_implementations [i].methods){
 529                                         if (mi == null)
 530                                                 continue;
 531
 532                                         if (type.IsInterface){
 533                                                 MethodInfo need_proxy =
 534                                                         pending_implementations [i].need_proxy [j];
 535
 536                                                 if (need_proxy != null) {
 537                                                         Type [] args = TypeManager.GetArgumentTypes (mi);
 538                                                         DefineProxy (type, need_proxy, mi, args);
 539                                                         continue;
 540                                                 }
 541
 542                                                 if (ParentImplements (type, mi))
 543                                                         continue;
 544
 545                                                 if (pending_implementations [i].optional)
 546                                                         continue;
 547
 548                                                 if (pending_implementations [i].found [j]) {
 549                                                         string[] methodLabel = TypeManager.CSharpSignature (mi).Split ('.');
 550                                                         Report.Error (536, container.Location, "'{0}' does not implement interface member '{1}'. '{2}.{3}' is either static, not public, or has the wrong return type",
 551                                                                 container.Name, TypeManager.CSharpSignature (mi), container.Name, methodLabel[methodLabel.Length - 1]);
 552                                                 }
 553                                                 else {
 554                                                         Report.Error (535, container.Location, "'{0}' does not implement interface member '{1}'",
 555                                                                 container.Name, TypeManager.CSharpSignature (mi));
 556                                                 }
 557                                         } else {
 558                                                 Report.Error (534, container.Location, "'{0}' does not implement inherited abstract member '{1}'",
 559                                                         container.Name, TypeManager.CSharpSignature (mi));
 560                                         }
 561                                         errors = true;
 562                                         j++;
 563                                 }
 564                         }
 565                         return errors;
 566                 }
 567         } /* end of class */
 568 }