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                 // Far from ideal, but we want to avoid creating a copy
  25                 // of methods above.
  26                 public Type [][]     args;
  27
  28                 //
  29                 // This flag on the method says `We found a match, but
  30                 // because it was private, we could not use the match
  31                 //
  32                 public bool []       found;
  33
  34                 // If a method is defined here, then we always need to
  35                 // create a proxy for it.  This is used when implementing
  36                 // an interface's indexer with a different IndexerName.
  37                 public MethodInfo [] need_proxy;
  38         }
  39
  40         public class PendingImplementation {
  41                 /// <summary>
  42                 ///   The container for this PendingImplementation
  43                 /// </summary>
  44                 TypeContainer container;
  45
  46                 /// <summary>
  47                 ///   This filter is used by FindMembers, and it is used to
  48                 ///   extract only virtual/abstract fields
  49                 /// </summary>
  50                 static MemberFilter virtual_method_filter;
  51
  52                 /// <summary>
  53                 ///   This is the array of TypeAndMethods that describes the pending implementations
  54                 ///   (both interfaces and abstract methods in parent class)
  55                 /// </summary>
  56                 TypeAndMethods [] pending_implementations;
  57
  58                 static bool IsVirtualFilter (MemberInfo m, object filterCriteria)
  59                 {
  60                         if (!(m is MethodInfo))
  61                                 return false;
  62
  63                         return ((MethodInfo) m).IsVirtual;
  64                 }
  65
  66                 /// <summary>
  67                 ///   Inits the virtual_method_filter
  68                 /// </summary>
  69                 static PendingImplementation ()
  70                 {
  71                         virtual_method_filter = new MemberFilter (IsVirtualFilter);
  72                 }
  73
  74                 // <remarks>
  75                 //   Returns a list of the abstract methods that are exposed by all of our
  76                 //   parents that we must implement.  Notice that this `flattens' the
  77                 //   method search space, and takes into account overrides.
  78                 // </remarks>
  79                 static ArrayList GetAbstractMethods (Type t)
  80                 {
  81                         ArrayList list = null;
  82                         bool searching = true;
  83                         Type current_type = t;
  84
  85                         do {
  86                                 MemberList mi;
  87
  88                                 mi = TypeContainer.FindMembers (
  89                                         current_type, MemberTypes.Method,
  90                                         BindingFlags.Public | BindingFlags.Instance |
  91                                         BindingFlags.DeclaredOnly,
  92                                         virtual_method_filter, null);
  93
  94                                 if (current_type == TypeManager.object_type)
  95                                         searching = false;
  96                                 else {
  97                                         current_type = current_type.BaseType;
  98                                         if (!current_type.IsAbstract)
  99                                                 searching = false;
 100                                 }
 101
 102                                 if (mi.Count == 0)
 103                                         continue;
 104
 105                                 if (mi.Count == 1 && !(mi [0] is MethodBase))
 106                                         searching = false;
 107                                 else
 108                                         list = TypeManager.CopyNewMethods (list, mi);
 109                         } while (searching);
 110
 111                         if (list == null)
 112                                 return null;
 113
 114                         for (int i = 0; i < list.Count; i++){
 115                                 while (list.Count > i && !((MethodInfo) list [i]).IsAbstract)
 116                                         list.RemoveAt (i);
 117                         }
 118
 119                         if (list.Count == 0)
 120                                 return null;
 121
 122                         return list;
 123                 }
 124
 125                 PendingImplementation (TypeContainer container, Type [] ifaces, ArrayList abstract_methods, int total)
 126                 {
 127                         TypeBuilder type_builder = container.TypeBuilder;
 128
 129                         this.container = container;
 130                         pending_implementations = new TypeAndMethods [total];
 131
 132                         int i = 0;
 133                         if (ifaces != null){
 134                                 foreach (Type t in ifaces){
 135                                         MethodInfo [] mi;
 136
 137                                         if (t is TypeBuilder){
 138                                                 Interface iface;
 139
 140                                                 iface = TypeManager.LookupInterface (t);
 141
 142                                                 mi = iface.GetMethods ();
 143                                         } else
 144                                                 mi = t.GetMethods ();
 145
 146                                         int count = mi.Length;
 147                                         pending_implementations [i].type = t;
 148                                         pending_implementations [i].methods = mi;
 149                                         pending_implementations [i].args = new Type [count][];
 150                                         pending_implementations [i].found = new bool [count];
 151                                         pending_implementations [i].need_proxy = new MethodInfo [count];
 152
 153                                         int j = 0;
 154                                         foreach (MethodInfo m in mi){
 155                                                 Type [] types = TypeManager.GetArgumentTypes (m);
 156
 157                                                 pending_implementations [i].args [j] = types;
 158                                                 j++;
 159                                         }
 160                                         i++;
 161                                 }
 162                         }
 163
 164                         if (abstract_methods != null){
 165                                 int count = abstract_methods.Count;
 166                                 pending_implementations [i].methods = new MethodInfo [count];
 167                                 pending_implementations [i].need_proxy = new MethodInfo [count];
 168
 169                                 abstract_methods.CopyTo (pending_implementations [i].methods, 0);
 170                                 pending_implementations [i].found = new bool [count];
 171                                 pending_implementations [i].args = new Type [count][];
 172                                 pending_implementations [i].type = type_builder;
 173
 174                                 int j = 0;
 175                                 foreach (MemberInfo m in abstract_methods){
 176                                         MethodInfo mi = (MethodInfo) m;
 177
 178                                         Type [] types = TypeManager.GetArgumentTypes (mi);
 179
 180                                         pending_implementations [i].args [j] = types;
 181                                         j++;
 182                                 }
 183                         }
 184                 }
 185
 186                 //
 187                 // Factory method: if there are pending implementation methods, we return a PendingImplementation
 188                 // object, otherwise we return null.
 189                 //
 190                 // Register method implementations are either abstract methods
 191                 // flagged as such on the base class or interface methods
 192                 //
 193                 static public PendingImplementation GetPendingImplementations (TypeContainer container)
 194                 {
 195                         TypeBuilder type_builder = container.TypeBuilder;
 196                         Type [] ifaces;
 197                         Type b = type_builder.BaseType;
 198                         int icount = 0;
 199
 200                         //
 201                         // Notice that TypeBuilders will only return the interfaces that the Type
 202                         // is supposed to implement, not all the interfaces that the type implements.
 203                         //
 204                         // Completely broken.  Anyways, we take advantage of this, so we only register
 205                         // the implementations that we need, as they are those that are listed by the
 206                         // TypeBuilder.
 207                         //
 208                         ifaces = type_builder.GetInterfaces ();
 209 #if DEBUG
 210                         {
 211                                 Type x = type_builder;
 212
 213                                 while (x != null){
 214                                         Type [] iff = x.GetInterfaces ();
 215                                         Console.WriteLine ("Type: " + x.Name);
 216
 217                                         foreach (Type tt in iff){
 218                                                 Console.WriteLine ("  Iface: " + tt.Name);
 219                                         }
 220                                         x = x.BaseType;
 221                                 }
 222                         }
 223 #endif
 224
 225                         icount = ifaces.Length;
 226
 227                         //
 228                         // If we are implementing an abstract class, and we are not
 229                         // ourselves abstract, and there are abstract methods (C# allows
 230                         // abstract classes that have no abstract methods), then allocate
 231                         // one slot.
 232                         //
 233                         // We also pre-compute the methods.
 234                         //
 235                         bool implementing_abstract = ((b != null) && b.IsAbstract && !type_builder.IsAbstract);
 236                         ArrayList abstract_methods = null;
 237
 238                         if (implementing_abstract){
 239                                 abstract_methods = GetAbstractMethods (b);
 240
 241                                 if (abstract_methods == null)
 242                                         implementing_abstract = false;
 243                         }
 244
 245                         int total = icount +  (implementing_abstract ? 1 : 0);
 246                         if (total == 0)
 247                                 return null;
 248
 249                         return new PendingImplementation (container, ifaces, abstract_methods, total);
 250                 }
 251
 252                 public enum Operation {
 253                         //
 254                         // If you change this, review the whole InterfaceMethod routine as there
 255                         // are a couple of assumptions on these three states
 256                         //
 257                         Lookup, ClearOne, ClearAll
 258                 }
 259
 260                 /// <summary>
 261                 ///   Whether the specified method is an interface method implementation
 262                 /// </summary>
 263                 public MethodInfo IsInterfaceMethod (Type t, string name, Type ret_type, Type [] args)
 264                 {
 265                         return InterfaceMethod (t, name, ret_type, args, Operation.Lookup, null);
 266                 }
 267
 268                 public MethodInfo IsInterfaceIndexer (Type t, Type ret_type, Type [] args)
 269                 {
 270                         return InterfaceMethod (t, null, ret_type, args, Operation.Lookup, null);
 271                 }
 272
 273                 public void ImplementMethod (Type t, string name, Type ret_type, Type [] args, bool clear_one)
 274                 {
 275                         InterfaceMethod (t, name, ret_type, args,
 276                                          clear_one ? Operation.ClearOne : Operation.ClearAll, null);
 277                 }
 278
 279                 public void ImplementIndexer (Type t, MethodInfo mi, Type ret_type, Type [] args, bool clear_one)
 280                 {
 281                         InterfaceMethod (t, mi.Name, ret_type, args,
 282                                          clear_one ? Operation.ClearOne : Operation.ClearAll, mi);
 283                 }
 284
 285                 /// <remarks>
 286                 ///   If a method in Type `t' (or null to look in all interfaces
 287                 ///   and the base abstract class) with name `Name', return type `ret_type' and
 288                 ///   arguments `args' implements an interface, this method will
 289                 ///   return the MethodInfo that this method implements.
 290                 ///
 291                 ///   If `name' is null, we operate solely on the method's signature.  This is for
 292                 ///   instance used when implementing indexers.
 293                 ///
 294                 ///   The `Operation op' controls whether to lookup, clear the pending bit, or clear
 295                 ///   all the methods with the given signature.
 296                 ///
 297                 ///   The `MethodInfo need_proxy' is used when we're implementing an interface's
 298                 ///   indexer in a class.  If the new indexer's IndexerName does not match the one
 299                 ///   that was used in the interface, then we always need to create a proxy for it.
 300                 ///
 301                 /// </remarks>
 302                 public MethodInfo InterfaceMethod (Type t, string name, Type ret_type, Type [] args,
 303                                                    Operation op, MethodInfo need_proxy)
 304                 {
 305                         int arg_len = args.Length;
 306
 307                         if (pending_implementations == null)
 308                                 return null;
 309
 310                         foreach (TypeAndMethods tm in pending_implementations){
 311                                 if (!(t == null || tm.type == t))
 312                                         continue;
 313
 314                                 int i = 0;
 315                                 foreach (MethodInfo m in tm.methods){
 316                                         if (m == null){
 317                                                 i++;
 318                                                 continue;
 319                                         }
 320
 321                                         // `need_proxy' is not null when we're implementing an
 322                                         // interface indexer and this is Clear(One/All) operation.
 323                                         // If `name' is null, then we do a match solely based on the
 324                                         // signature and not on the name (this is done in the Lookup
 325                                         // for an interface indexer).
 326                                         if ((name != null) && (need_proxy == null) && (name != m.Name)){
 327                                                 i++;
 328                                                 continue;
 329                                         }
 330
 331                                         if (ret_type != m.ReturnType){
 332                                                 if (!((ret_type == null && m.ReturnType == TypeManager.void_type) ||
 333                                                       (m.ReturnType == null && ret_type == TypeManager.void_type)))
 334                                                 {
 335                                                         i++;
 336                                                         continue;
 337                                                 }
 338                                         }
 339
 340                                         //
 341                                         // Check if we have the same parameters
 342                                         //
 343                                         if (tm.args [i].Length != arg_len){
 344                                                 i++;
 345                                                 continue;
 346                                         }
 347
 348                                         int j, top = args.Length;
 349                                         bool fail = false;
 350
 351                                         for (j = 0; j < top; j++){
 352                                                 if (tm.args [i][j] != args[j]){
 353                                                         fail = true;
 354                                                         break;
 355                                                 }
 356                                         }
 357                                         if (fail){
 358                                                 i++;
 359                                                 continue;
 360                                         }
 361
 362                                         if (op != Operation.Lookup){
 363                                                 // If `t != null', then this is an explicitly interface
 364                                                 // implementation and we can always clear the method.
 365                                                 // `need_proxy' is not null if we're implementing an
 366                                                 // interface indexer.  In this case, we need to create
 367                                                 // a proxy if the implementation's IndexerName doesn't
 368                                                 // match the IndexerName in the interface.
 369                                                 if ((t == null) && (need_proxy != null) && (name != m.Name))
 370                                                         tm.need_proxy [i] = need_proxy;
 371                                                 else
 372                                                         tm.methods [i] = null;
 373                                         }
 374                                         tm.found [i] = true;
 375
 376                                         //
 377                                         // Lookups and ClearOne return
 378                                         //
 379                                         if (op != Operation.ClearAll)
 380                                                 return m;
 381                                 }
 382
 383                                 // If a specific type was requested, we can stop now.
 384                                 if (tm.type == t)
 385                                         return null;
 386                         }
 387                         return null;
 388                 }
 389
 390                 /// <summary>
 391                 ///   C# allows this kind of scenarios:
 392                 ///   interface I { void M (); }
 393                 ///   class X { public void M (); }
 394                 ///   class Y : X, I { }
 395                 ///
 396                 ///   For that case, we create an explicit implementation function
 397                 ///   I.M in Y.
 398                 /// </summary>
 399                 void DefineProxy (Type iface, MethodInfo parent_method, MethodInfo iface_method,
 400                                   Type [] args)
 401                 {
 402                         MethodBuilder proxy;
 403
 404                         string proxy_name = iface.Name + "." + iface_method.Name;
 405
 406                         proxy = container.TypeBuilder.DefineMethod (
 407                                 proxy_name,
 408                                 MethodAttributes.HideBySig |
 409                                 MethodAttributes.NewSlot |
 410                                 MethodAttributes.Virtual,
 411                                 CallingConventions.Standard | CallingConventions.HasThis,
 412                                 parent_method.ReturnType, args);
 413
 414                         int top = args.Length;
 415                         ILGenerator ig = proxy.GetILGenerator ();
 416
 417                         ig.Emit (OpCodes.Ldarg_0);
 418                         for (int i = 0; i < top; i++){
 419                                 switch (i){
 420                                 case 0:
 421                                         ig.Emit (OpCodes.Ldarg_1); break;
 422                                 case 1:
 423                                         ig.Emit (OpCodes.Ldarg_2); break;
 424                                 case 2:
 425                                         ig.Emit (OpCodes.Ldarg_3); break;
 426                                 default:
 427                                         ig.Emit (OpCodes.Ldarg, i - 1); break;
 428                                 }
 429                         }
 430                         ig.Emit (OpCodes.Call, parent_method);
 431                         ig.Emit (OpCodes.Ret);
 432
 433                         container.TypeBuilder.DefineMethodOverride (proxy, iface_method);
 434                 }
 435
 436                 /// <summary>
 437                 ///   This function tells whether one of our parent classes implements
 438                 ///   the given method (which turns out, it is valid to have an interface
 439                 ///   implementation in a parent
 440                 /// </summary>
 441                 bool ParentImplements (Type iface_type, MethodInfo mi)
 442                 {
 443                         MethodSignature ms;
 444
 445                         Type [] args = TypeManager.GetArgumentTypes (mi);
 446                         ms = new MethodSignature (mi.Name, mi.ReturnType, args);
 447                         MemberList list = TypeContainer.FindMembers (
 448                                 container.TypeBuilder.BaseType, MemberTypes.Method | MemberTypes.Property,
 449                                 BindingFlags.Public | BindingFlags.Instance,
 450                                 MethodSignature.method_signature_filter, ms);
 451
 452                         if (list.Count == 0)
 453                                 return false;
 454
 455                         DefineProxy (iface_type, (MethodInfo) list [0], mi, args);
 456                         return true;
 457                 }
 458
 459                 /// <summary>
 460                 ///   Verifies that any pending abstract methods or interface methods
 461                 ///   were implemented.
 462                 /// </summary>
 463                 public bool VerifyPendingMethods ()
 464                 {
 465                         int top = pending_implementations.Length;
 466                         bool errors = false;
 467                         int i;
 468
 469                         for (i = 0; i < top; i++){
 470                                 Type type = pending_implementations [i].type;
 471                                 int j = 0;
 472
 473                                 foreach (MethodInfo mi in pending_implementations [i].methods){
 474                                         if (mi == null)
 475                                                 continue;
 476
 477                                         if (type.IsInterface){
 478                                                 MethodInfo need_proxy =
 479                                                         pending_implementations [i].need_proxy [j];
 480
 481                                                 if (need_proxy != null) {
 482                                                         Type [] args = TypeManager.GetArgumentTypes (mi);
 483                                                         DefineProxy (type, need_proxy, mi, args);
 484                                                         continue;
 485                                                 }
 486
 487                                                 if (ParentImplements (type, mi))
 488                                                         continue;
 489
 490                                                 string extra = "";
 491
 492                                                 if (pending_implementations [i].found [j])
 493                                                         extra = ".  (method might be private or static)";
 494                                                 Report.Error (
 495                                                         536, container.Location,
 496                                                         "`" + container.Name + "' does not implement " +
 497                                                         "interface member `" +
 498                                                         type.FullName + "." + mi.Name + "'" + extra);
 499                                         } else {
 500                                                 Report.Error (
 501                                                         534, container.Location,
 502                                                         "`" + container.Name + "' does not implement " +
 503                                                         "inherited abstract member `" +
 504                                                         type.FullName + "." + mi.Name + "'");
 505                                         }
 506                                         errors = true;
 507                                         j++;
 508                                 }
 509                         }
 510                         return errors;
 511                 }
 512         } /* end of class */
 513 }