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                                 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 (container);
 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
 210 #if DEBUG
 211                         {
 212                                 Type x = type_builder;
 213
 214                                 while (x != null){
 215                                         Type [] iff = x.GetInterfaces ();
 216                                         Console.WriteLine ("Type: " + x.Name);
 217
 218                                         foreach (Type tt in iff){
 219                                                 Console.WriteLine ("  Iface: " + tt.Name);
 220                                         }
 221                                         x = x.BaseType;
 222                                 }
 223                         }
 224 #endif
 225
 226                         icount = ifaces.Length;
 227
 228                         //
 229                         // If we are implementing an abstract class, and we are not
 230                         // ourselves abstract, and there are abstract methods (C# allows
 231                         // abstract classes that have no abstract methods), then allocate
 232                         // one slot.
 233                         //
 234                         // We also pre-compute the methods.
 235                         //
 236                         bool implementing_abstract = ((b != null) && b.IsAbstract && !type_builder.IsAbstract);
 237                         ArrayList abstract_methods = null;
 238
 239                         if (implementing_abstract){
 240                                 abstract_methods = GetAbstractMethods (b);
 241
 242                                 if (abstract_methods == null)
 243                                         implementing_abstract = false;
 244                         }
 245
 246                         int total = icount +  (implementing_abstract ? 1 : 0);
 247                         if (total == 0)
 248                                 return null;
 249
 250                         return new PendingImplementation (container, ifaces, abstract_methods, total);
 251                 }
 252
 253                 public enum Operation {
 254                         //
 255                         // If you change this, review the whole InterfaceMethod routine as there
 256                         // are a couple of assumptions on these three states
 257                         //
 258                         Lookup, ClearOne, ClearAll
 259                 }
 260
 261                 /// <summary>
 262                 ///   Whether the specified method is an interface method implementation
 263                 /// </summary>
 264                 public MethodInfo IsInterfaceMethod (Type t, string name, Type ret_type, Type [] args)
 265                 {
 266                         return InterfaceMethod (t, name, ret_type, args, Operation.Lookup, null);
 267                 }
 268
 269                 public MethodInfo IsInterfaceIndexer (Type t, Type ret_type, Type [] args)
 270                 {
 271                         return InterfaceMethod (t, null, ret_type, args, Operation.Lookup, null);
 272                 }
 273
 274                 public void ImplementMethod (Type t, string name, Type ret_type, Type [] args, bool clear_one)
 275                 {
 276                         InterfaceMethod (t, name, ret_type, args,
 277                                          clear_one ? Operation.ClearOne : Operation.ClearAll, null);
 278                 }
 279
 280                 public void ImplementIndexer (Type t, MethodInfo mi, Type ret_type, Type [] args, bool clear_one)
 281                 {
 282                         InterfaceMethod (t, mi.Name, ret_type, args,
 283                                          clear_one ? Operation.ClearOne : Operation.ClearAll, mi);
 284                 }
 285
 286                 /// <remarks>
 287                 ///   If a method in Type `t' (or null to look in all interfaces
 288                 ///   and the base abstract class) with name `Name', return type `ret_type' and
 289                 ///   arguments `args' implements an interface, this method will
 290                 ///   return the MethodInfo that this method implements.
 291                 ///
 292                 ///   If `name' is null, we operate solely on the method's signature.  This is for
 293                 ///   instance used when implementing indexers.
 294                 ///
 295                 ///   The `Operation op' controls whether to lookup, clear the pending bit, or clear
 296                 ///   all the methods with the given signature.
 297                 ///
 298                 ///   The `MethodInfo need_proxy' is used when we're implementing an interface's
 299                 ///   indexer in a class.  If the new indexer's IndexerName does not match the one
 300                 ///   that was used in the interface, then we always need to create a proxy for it.
 301                 ///
 302                 /// </remarks>
 303                 public MethodInfo InterfaceMethod (Type t, string name, Type ret_type, Type [] args,
 304                                                    Operation op, MethodInfo need_proxy)
 305                 {
 306                         int arg_len = args.Length;
 307
 308                         if (pending_implementations == null)
 309                                 return null;
 310
 311                         foreach (TypeAndMethods tm in pending_implementations){
 312                                 if (!(t == null || tm.type == t))
 313                                         continue;
 314
 315                                 int i = 0;
 316                                 foreach (MethodInfo m in tm.methods){
 317                                         if (m == null){
 318                                                 i++;
 319                                                 continue;
 320                                         }
 321
 322                                         // `need_proxy' is not null when we're implementing an
 323                                         // interface indexer and this is Clear(One/All) operation.
 324                                         // If `name' is null, then we do a match solely based on the
 325                                         // signature and not on the name (this is done in the Lookup
 326                                         // for an interface indexer).
 327                                         if ((name != null) && (need_proxy == null) && (name != m.Name)){
 328                                                 i++;
 329                                                 continue;
 330                                         }
 331
 332                                         if (ret_type != m.ReturnType){
 333                                                 if (!((ret_type == null && m.ReturnType == TypeManager.void_type) ||
 334                                                       (m.ReturnType == null && ret_type == TypeManager.void_type)))
 335                                                 {
 336                                                         i++;
 337                                                         continue;
 338                                                 }
 339                                         }
 340
 341                                         //
 342                                         // Check if we have the same parameters
 343                                         //
 344                                         if (tm.args [i].Length != arg_len){
 345                                                 i++;
 346                                                 continue;
 347                                         }
 348
 349                                         int j, top = args.Length;
 350                                         bool fail = false;
 351
 352                                         for (j = 0; j < top; j++){
 353                                                 if (tm.args [i][j] != args[j]){
 354                                                         fail = true;
 355                                                         break;
 356                                                 }
 357                                         }
 358                                         if (fail){
 359                                                 i++;
 360                                                 continue;
 361                                         }
 362
 363                                         if (op != Operation.Lookup){
 364                                                 // If `t != null', then this is an explicitly interface
 365                                                 // implementation and we can always clear the method.
 366                                                 // `need_proxy' is not null if we're implementing an
 367                                                 // interface indexer.  In this case, we need to create
 368                                                 // a proxy if the implementation's IndexerName doesn't
 369                                                 // match the IndexerName in the interface.
 370                                                 if ((t == null) && (need_proxy != null) && (name != m.Name))
 371                                                         tm.need_proxy [i] = need_proxy;
 372                                                 else
 373                                                         tm.methods [i] = null;
 374                                         }
 375                                         tm.found [i] = true;
 376
 377                                         //
 378                                         // Lookups and ClearOne return
 379                                         //
 380                                         if (op != Operation.ClearAll)
 381                                                 return m;
 382                                 }
 383
 384                                 // If a specific type was requested, we can stop now.
 385                                 if (tm.type == t)
 386                                         return null;
 387                         }
 388                         return null;
 389                 }
 390
 391                 /// <summary>
 392                 ///   C# allows this kind of scenarios:
 393                 ///   interface I { void M (); }
 394                 ///   class X { public void M (); }
 395                 ///   class Y : X, I { }
 396                 ///
 397                 ///   For that case, we create an explicit implementation function
 398                 ///   I.M in Y.
 399                 /// </summary>
 400                 void DefineProxy (Type iface, MethodInfo parent_method, MethodInfo iface_method,
 401                                   Type [] args)
 402                 {
 403                         MethodBuilder proxy;
 404
 405                         string proxy_name = iface.Name + "." + iface_method.Name;
 406
 407                         proxy = container.TypeBuilder.DefineMethod (
 408                                 proxy_name,
 409                                 MethodAttributes.HideBySig |
 410                                 MethodAttributes.NewSlot |
 411                                 MethodAttributes.Virtual,
 412                                 CallingConventions.Standard | CallingConventions.HasThis,
 413                                 parent_method.ReturnType, args);
 414
 415                         int top = args.Length;
 416                         ILGenerator ig = proxy.GetILGenerator ();
 417
 418                         ig.Emit (OpCodes.Ldarg_0);
 419                         for (int i = 0; i < top; i++){
 420                                 switch (i){
 421                                 case 0:
 422                                         ig.Emit (OpCodes.Ldarg_1); break;
 423                                 case 1:
 424                                         ig.Emit (OpCodes.Ldarg_2); break;
 425                                 case 2:
 426                                         ig.Emit (OpCodes.Ldarg_3); break;
 427                                 default:
 428                                         ig.Emit (OpCodes.Ldarg, i - 1); break;
 429                                 }
 430                         }
 431                         ig.Emit (OpCodes.Call, parent_method);
 432                         ig.Emit (OpCodes.Ret);
 433
 434                         container.TypeBuilder.DefineMethodOverride (proxy, iface_method);
 435                 }
 436
 437                 static bool IsPropertyGetMethod (string m)
 438                 {
 439                         return (m.Substring (0, 4) == "get_");
 440                 }
 441
 442                 static bool IsPropertySetMethod (string m)
 443                 {
 444                         return (m.Substring (0, 4) == "set_");
 445                 }
 446
 447                 MethodInfo FindExplicitImplementation (string iface_name, string method_name)
 448                 {
 449                         if (container.Properties != null) {
 450                                 foreach (Property p in container.Properties)
 451                                 {
 452                                         if (p.Implements != null) {
 453                                                 if (IsPropertyGetMethod (method_name) && (p.Implements.ToString() == iface_name + "." + method_name.Substring(4)))
 454                                                                 return p.PropertyBuilder.GetGetMethod(true);
 455
 456                                                 if (IsPropertySetMethod (method_name) && (p.Implements.ToString() == iface_name + "." + method_name.Substring(4)))
 457                                                                 return p.PropertyBuilder.GetSetMethod(true);
 458                                         }
 459                                 }
 460                         }
 461
 462                         if (container.Methods != null)
 463                         {
 464                                 foreach (Method m in container.Methods)
 465                                 {
 466                                         if (m.Implements != null)
 467                                         {
 468                                                 if (m.Implements.ToString() == iface_name + "." + method_name.Substring(4))
 469                                                         return (MethodInfo) m.MethodBuilder;
 470                                         }
 471                                 }
 472                         }
 473                         return null;
 474                 }
 475
 476                 /// <summary>
 477                 ///   This function tells whether one of our parent classes implements
 478                 ///   the given method (which turns out, it is valid to have an interface
 479                 ///   implementation in a parent
 480                 /// </summary>
 481                 bool ParentImplements (Type iface_type, MethodInfo mi)
 482                 {
 483                         MethodSignature ms;
 484                         MethodInfo mr;
 485
 486                         Type [] args = TypeManager.GetArgumentTypes (mi);
 487
 488                         ms = new MethodSignature (mi.Name, mi.ReturnType, args);
 489                         MemberList list = TypeContainer.FindMembers (
 490                                 container.TypeBuilder.BaseType, MemberTypes.Method | MemberTypes.Property,
 491                                 BindingFlags.Public | BindingFlags.Instance,
 492                                 MethodSignature.method_signature_filter, ms);
 493
 494                         if (list.Count == 0)
 495                         {
 496                                 mr = FindExplicitImplementation (iface_type.ToString(), mi.Name);
 497                                 if (mr == null)
 498                                         return false;
 499                         }
 500                         else
 501                                 mr = (MethodInfo) list[0];
 502
 503                         DefineProxy (iface_type, mr, mi, args);
 504                         return true;
 505                 }
 506
 507                 /// <summary>
 508                 ///   Verifies that any pending abstract methods or interface methods
 509                 ///   were implemented.
 510                 /// </summary>
 511                 public bool VerifyPendingMethods ()
 512                 {
 513                         int top = pending_implementations.Length;
 514                         bool errors = false;
 515                         int i;
 516
 517                         for (i = 0; i < top; i++){
 518                                 Type type = pending_implementations [i].type;
 519                                 int j = 0;
 520
 521                                 foreach (MethodInfo mi in pending_implementations [i].methods){
 522                                         if (mi == null)
 523                                                 continue;
 524
 525                                         if (type.IsInterface){
 526                                                 MethodInfo need_proxy =
 527                                                         pending_implementations [i].need_proxy [j];
 528
 529                                                 if (need_proxy != null) {
 530                                                         Type [] args = TypeManager.GetArgumentTypes (mi);
 531                                                         DefineProxy (type, need_proxy, mi, args);
 532                                                         continue;
 533                                                 }
 534
 535                                                 if (ParentImplements (type, mi))
 536                                                         continue;
 537
 538                                                 string extra = "";
 539
 540                                                 if (pending_implementations [i].found [j])
 541                                                         extra = ".  (method might be private or static)";
 542                                                 Report.Error (
 543                                                         536, container.Location,
 544                                                         "`" + container.Name + "' does not implement " +
 545                                                         "interface member `" +
 546                                                         type.FullName + "." + mi.Name + "'" + extra);
 547                                         } else {
 548                                                 Report.Error (
 549                                                         534, container.Location,
 550                                                         "`" + container.Name + "' does not implement " +
 551                                                         "inherited abstract member `" +
 552                                                         type.FullName + "." + mi.Name + "'");
 553                                         }
 554                                         errors = true;
 555                                         j++;
 556                                 }
 557                         }
 558                         return errors;
 559                 }
 560         } /* end of class */
 561 }