mcs/mbas/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                                 MemberInfo [] 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 == null)
 103                                         continue;
 104
 105                                 int count = mi.Length;
 106                                 if (count == 0)
 107                                         continue;
 108
 109                                 if (count == 1 && !(mi [0] is MethodBase))
 110                                         searching = false;
 111                                 else
 112                                         list = TypeManager.CopyNewMethods (list, mi);
 113                         } while (searching);
 114
 115                         if (list == null)
 116                                 return null;
 117
 118                         for (int i = 0; i < list.Count; i++){
 119                                 while (list.Count > i && !((MethodInfo) list [i]).IsAbstract)
 120                                         list.RemoveAt (i);
 121                         }
 122
 123                         if (list.Count == 0)
 124                                 return null;
 125
 126                         return list;
 127                 }
 128
 129                 PendingImplementation (TypeContainer container, Type [] ifaces, ArrayList abstract_methods, int total)
 130                 {
 131                         TypeBuilder type_builder = container.TypeBuilder;
 132
 133                         this.container = container;
 134                         pending_implementations = new TypeAndMethods [total];
 135
 136                         int i = 0;
 137                         if (ifaces != null){
 138                                 foreach (Type t in ifaces){
 139                                         MethodInfo [] mi;
 140
 141                                         if (t is TypeBuilder){
 142                                                 Interface iface;
 143
 144                                                 iface = TypeManager.LookupInterface (t);
 145
 146                                                 mi = iface.GetMethods ();
 147                                         } else
 148                                                 mi = t.GetMethods ();
 149
 150                                         int count = mi.Length;
 151                                         pending_implementations [i].type = t;
 152                                         pending_implementations [i].methods = mi;
 153                                         pending_implementations [i].args = new Type [count][];
 154                                         pending_implementations [i].found = new bool [count];
 155                                         pending_implementations [i].need_proxy = new MethodInfo [count];
 156
 157                                         int j = 0;
 158                                         foreach (MethodInfo m in mi){
 159                                                 Type [] types = TypeManager.GetArgumentTypes (m);
 160
 161                                                 pending_implementations [i].args [j] = types;
 162                                                 j++;
 163                                         }
 164                                         i++;
 165                                 }
 166                         }
 167
 168                         if (abstract_methods != null){
 169                                 int count = abstract_methods.Count;
 170                                 pending_implementations [i].methods = new MethodInfo [count];
 171                                 pending_implementations [i].need_proxy = new MethodInfo [count];
 172
 173                                 abstract_methods.CopyTo (pending_implementations [i].methods, 0);
 174                                 pending_implementations [i].found = new bool [count];
 175                                 pending_implementations [i].args = new Type [count][];
 176                                 pending_implementations [i].type = type_builder;
 177
 178                                 int j = 0;
 179                                 foreach (MemberInfo m in abstract_methods){
 180                                         MethodInfo mi = (MethodInfo) m;
 181
 182                                         Type [] types = TypeManager.GetArgumentTypes (mi);
 183
 184                                         pending_implementations [i].args [j] = types;
 185                                         j++;
 186                                 }
 187                         }
 188                 }
 189
 190                 //
 191                 // Factory method: if there are pending implementation methods, we return a PendingImplementation
 192                 // object, otherwise we return null.
 193                 //
 194                 // Register method implementations are either abstract methods
 195                 // flagged as such on the base class or interface methods
 196                 //
 197                 static public PendingImplementation GetPendingImplementations (TypeContainer container)
 198                 {
 199                         TypeBuilder type_builder = container.TypeBuilder;
 200                         Type [] ifaces;
 201                         Type b = type_builder.BaseType;
 202                         int icount = 0;
 203
 204                         //
 205                         // Notice that TypeBuilders will only return the interfaces that the Type
 206                         // is supposed to implement, not all the interfaces that the type implements.
 207                         //
 208                         // Completely broken.  Anyways, we take advantage of this, so we only register
 209                         // the implementations that we need, as they are those that are listed by the
 210                         // TypeBuilder.
 211                         //
 212                         ifaces = type_builder.GetInterfaces ();
 213 #if DEBUG
 214                         {
 215                                 Type x = type_builder;
 216
 217                                 while (x != null){
 218                                         Type [] iff = x.GetInterfaces ();
 219                                         Console.WriteLine ("Type: " + x.Name);
 220
 221                                         foreach (Type tt in iff){
 222                                                 Console.WriteLine ("  Iface: " + tt.Name);
 223                                         }
 224                                         x = x.BaseType;
 225                                 }
 226                         }
 227 #endif
 228
 229                         icount = ifaces.Length;
 230
 231                         //
 232                         // If we are implementing an abstract class, and we are not
 233                         // ourselves abstract, and there are abstract methods (C# allows
 234                         // abstract classes that have no abstract methods), then allocate
 235                         // one slot.
 236                         //
 237                         // We also pre-compute the methods.
 238                         //
 239                         bool implementing_abstract = ((b != null) && b.IsAbstract && !type_builder.IsAbstract);
 240                         ArrayList abstract_methods = null;
 241
 242                         if (implementing_abstract){
 243                                 abstract_methods = GetAbstractMethods (b);
 244
 245                                 if (abstract_methods == null)
 246                                         implementing_abstract = false;
 247                         }
 248
 249                         int total = icount +  (implementing_abstract ? 1 : 0);
 250                         if (total == 0)
 251                                 return null;
 252
 253                         return new PendingImplementation (container, ifaces, abstract_methods, total);
 254                 }
 255
 256                 public enum Operation {
 257                         //
 258                         // If you change this, review the whole InterfaceMethod routine as there
 259                         // are a couple of assumptions on these three states
 260                         //
 261                         Lookup, ClearOne, ClearAll
 262                 }
 263
 264                 /// <summary>
 265                 ///   Whether the specified method is an interface method implementation
 266                 /// </summary>
 267                 public MethodInfo IsInterfaceMethod (Type t, string name, Type ret_type, Type [] args)
 268                 {
 269                         return InterfaceMethod (t, name, ret_type, args, Operation.Lookup, null);
 270                 }
 271
 272                 public MethodInfo IsInterfaceIndexer (Type t, Type ret_type, Type [] args)
 273                 {
 274                         return InterfaceMethod (t, null, ret_type, args, Operation.Lookup, null);
 275                 }
 276
 277                 public void ImplementMethod (Type t, string name, Type ret_type, Type [] args, bool clear_one)
 278                 {
 279                         InterfaceMethod (t, name, ret_type, args,
 280                                          clear_one ? Operation.ClearOne : Operation.ClearAll, null);
 281                 }
 282
 283                 public void ImplementIndexer (Type t, MethodInfo mi, Type ret_type, Type [] args, bool clear_one)
 284                 {
 285                         InterfaceMethod (t, mi.Name, ret_type, args,
 286                                          clear_one ? Operation.ClearOne : Operation.ClearAll, mi);
 287                 }
 288
 289                 /// <remarks>
 290                 ///   If a method in Type `t' (or null to look in all interfaces
 291                 ///   and the base abstract class) with name `Name', return type `ret_type' and
 292                 ///   arguments `args' implements an interface, this method will
 293                 ///   return the MethodInfo that this method implements.
 294                 ///
 295                 ///   If `name' is null, we operate solely on the method's signature.  This is for
 296                 ///   instance used when implementing indexers.
 297                 ///
 298                 ///   The `Operation op' controls whether to lookup, clear the pending bit, or clear
 299                 ///   all the methods with the given signature.
 300                 ///
 301                 ///   The `MethodInfo need_proxy' is used when we're implementing an interface's
 302                 ///   indexer in a class.  If the new indexer's IndexerName does not match the one
 303                 ///   that was used in the interface, then we always need to create a proxy for it.
 304                 ///
 305                 /// </remarks>
 306                 public MethodInfo InterfaceMethod (Type t, string name, Type ret_type, Type [] args,
 307                                                    Operation op, MethodInfo need_proxy)
 308                 {
 309                         int arg_len = args.Length;
 310
 311                         if (pending_implementations == null)
 312                                 return null;
 313
 314                         foreach (TypeAndMethods tm in pending_implementations){
 315                                 if (!(t == null || tm.type == t))
 316                                         continue;
 317
 318                                 int i = 0;
 319                                 foreach (MethodInfo m in tm.methods){
 320                                         if (m == null){
 321                                                 i++;
 322                                                 continue;
 323                                         }
 324
 325                                         // `need_proxy' is not null when we're implementing an
 326                                         // interface indexer and this is Clear(One/All) operation.
 327                                         // If `name' is null, then we do a match solely based on the
 328                                         // signature and not on the name (this is done in the Lookup
 329                                         // for an interface indexer).
 330                                         if ((name != null) && (need_proxy == null) && (name != m.Name)){
 331                                                 i++;
 332                                                 continue;
 333                                         }
 334
 335                                         if (ret_type != m.ReturnType){
 336                                                 if (!((ret_type == null && m.ReturnType == TypeManager.void_type) ||
 337                                                       (m.ReturnType == null && ret_type == TypeManager.void_type)))
 338                                                 {
 339                                                         i++;
 340                                                         continue;
 341                                                 }
 342                                         }
 343
 344                                         //
 345                                         // Check if we have the same parameters
 346                                         //
 347                                         if (tm.args [i].Length != arg_len){
 348                                                 i++;
 349                                                 continue;
 350                                         }
 351
 352                                         int j, top = args.Length;
 353                                         bool fail = false;
 354
 355                                         for (j = 0; j < top; j++){
 356                                                 if (tm.args [i][j] != args[j]){
 357                                                         fail = true;
 358                                                         break;
 359                                                 }
 360                                         }
 361                                         if (fail){
 362                                                 i++;
 363                                                 continue;
 364                                         }
 365
 366                                         if (op != Operation.Lookup){
 367                                                 // If `t != null', then this is an explicitly interface
 368                                                 // implementation and we can always clear the method.
 369                                                 // `need_proxy' is not null if we're implementing an
 370                                                 // interface indexer.  In this case, we need to create
 371                                                 // a proxy if the implementation's IndexerName doesn't
 372                                                 // match the IndexerName in the interface.
 373                                                 if ((t == null) && (need_proxy != null) && (name != m.Name))
 374                                                         tm.need_proxy [i] = need_proxy;
 375                                                 else
 376                                                         tm.methods [i] = null;
 377                                         }
 378                                         tm.found [i] = true;
 379
 380                                         //
 381                                         // Lookups and ClearOne return
 382                                         //
 383                                         if (op != Operation.ClearAll)
 384                                                 return m;
 385                                 }
 386
 387                                 // If a specific type was requested, we can stop now.
 388                                 if (tm.type == t)
 389                                         return null;
 390                         }
 391                         return null;
 392                 }
 393
 394                 /// <summary>
 395                 ///   C# allows this kind of scenarios:
 396                 ///   interface I { void M (); }
 397                 ///   class X { public void M (); }
 398                 ///   class Y : X, I { }
 399                 ///
 400                 ///   For that case, we create an explicit implementation function
 401                 ///   I.M in Y.
 402                 /// </summary>
 403                 void DefineProxy (Type iface, MethodInfo parent_method, MethodInfo iface_method,
 404                                   Type [] args)
 405                 {
 406                         MethodBuilder proxy;
 407
 408                         string proxy_name = iface.Name + "." + iface_method.Name;
 409
 410                         proxy = container.TypeBuilder.DefineMethod (
 411                                 proxy_name,
 412                                 MethodAttributes.HideBySig |
 413                                 MethodAttributes.NewSlot |
 414                                 MethodAttributes.Virtual,
 415                                 CallingConventions.Standard | CallingConventions.HasThis,
 416                                 parent_method.ReturnType, args);
 417
 418                         int top = args.Length;
 419                         ILGenerator ig = proxy.GetILGenerator ();
 420
 421                         ig.Emit (OpCodes.Ldarg_0);
 422                         for (int i = 0; i < top; i++){
 423                                 switch (i){
 424                                 case 0:
 425                                         ig.Emit (OpCodes.Ldarg_1); break;
 426                                 case 1:
 427                                         ig.Emit (OpCodes.Ldarg_2); break;
 428                                 case 2:
 429                                         ig.Emit (OpCodes.Ldarg_3); break;
 430                                 default:
 431                                         ig.Emit (OpCodes.Ldarg, i - 1); break;
 432                                 }
 433                         }
 434                         ig.Emit (OpCodes.Call, parent_method);
 435                         ig.Emit (OpCodes.Ret);
 436
 437                         container.TypeBuilder.DefineMethodOverride (proxy, iface_method);
 438                 }
 439
 440                 /// <summary>
 441                 ///   This function tells whether one of our parent classes implements
 442                 ///   the given method (which turns out, it is valid to have an interface
 443                 ///   implementation in a parent
 444                 /// </summary>
 445                 bool ParentImplements (Type iface_type, MethodInfo mi)
 446                 {
 447                         MethodSignature ms;
 448
 449                         Type [] args = TypeManager.GetArgumentTypes (mi);
 450                         ms = new MethodSignature (mi.Name, mi.ReturnType, args);
 451                         MemberInfo [] list = TypeContainer.FindMembers (
 452                                 container.TypeBuilder.BaseType, MemberTypes.Method | MemberTypes.Property,
 453                                 BindingFlags.Public | BindingFlags.Instance,
 454                                 MethodSignature.method_signature_filter, ms);
 455
 456                         if (list == null || list.Length == 0)
 457                                 return false;
 458
 459                         DefineProxy (iface_type, (MethodInfo) list [0], mi, args);
 460                         return true;
 461                 }
 462
 463                 /// <summary>
 464                 ///   Verifies that any pending abstract methods or interface methods
 465                 ///   were implemented.
 466                 /// </summary>
 467                 public bool VerifyPendingMethods ()
 468                 {
 469                         int top = pending_implementations.Length;
 470                         bool errors = false;
 471                         int i;
 472
 473                         for (i = 0; i < top; i++){
 474                                 Type type = pending_implementations [i].type;
 475                                 int j = 0;
 476
 477                                 foreach (MethodInfo mi in pending_implementations [i].methods){
 478                                         if (mi == null)
 479                                                 continue;
 480
 481                                         if (type.IsInterface){
 482                                                 MethodInfo need_proxy =
 483                                                         pending_implementations [i].need_proxy [j];
 484
 485                                                 if (need_proxy != null) {
 486                                                         Type [] args = TypeManager.GetArgumentTypes (mi);
 487                                                         DefineProxy (type, need_proxy, mi, args);
 488                                                         continue;
 489                                                 }
 490
 491                                                 if (ParentImplements (type, mi))
 492                                                         continue;
 493
 494                                                 string extra = "";
 495
 496                                                 if (pending_implementations [i].found [j])
 497                                                         extra = ".  (method might be private or static)";
 498                                                 Report.Error (
 499                                                         536, container.Location,
 500                                                         "`" + container.Name + "' does not implement " +
 501                                                         "interface member `" +
 502                                                         type.FullName + "." + mi.Name + "'" + extra);
 503                                         } else {
 504                                                 Report.Error (
 505                                                         534, container.Location,
 506                                                         "`" + container.Name + "' does not implement " +
 507                                                         "inherited abstract member `" +
 508                                                         type.FullName + "." + mi.Name + "'");
 509                                         }
 510                                         errors = true;
 511                                         j++;
 512                                 }
 513                         }
 514                         return errors;
 515                 }
 516         } /* end of class */
 517 }