mcs/mbas/decl.cs

   1 //
   2 // decl.cs: Declaration base class for structs, classes, enums and interfaces.
   3 //
   4 // Author: Miguel de Icaza (miguel@gnu.org)
   5 //
   6 // Licensed under the terms of the GNU GPL
   7 //
   8 // (C) 2001 Ximian, Inc (http://www.ximian.com)
   9 //
  10 // TODO: Move the method verification stuff from the class.cs and interface.cs here
  11 //
  12
  13 using System;
  14 using System.Collections;
  15 using System.Reflection.Emit;
  16 using System.Reflection;
  17
  18 namespace Mono.MonoBASIC {
  19
  20         /// <summary>
  21         ///   Base representation for members.  This is only used to keep track
  22         ///   of Name, Location and Modifier flags.
  23         /// </summary>
  24         public abstract class MemberCore {
  25                 /// <summary>
  26                 ///   Public name
  27                 /// </summary>
  28                 public string Name;
  29
  30                 /// <summary>
  31                 ///   Modifier flags that the user specified in the source code
  32                 /// </summary>
  33                 public int ModFlags;
  34
  35                 /// <summary>
  36                 ///   Location where this declaration happens
  37                 /// </summary>
  38                 public readonly Location Location;
  39
  40                 public MemberCore (string name, Location loc)
  41                 {
  42                         Name = name;
  43                         Location = loc;
  44                 }
  45
  46                 protected void WarningNotHiding (TypeContainer parent)
  47                 {
  48                         /*Report.Warning (
  49                                 109, Location,
  50                                 "The member " + parent.MakeName (Name) + " does not hide an " +
  51                                 "inherited member.  The keyword new is not required");
  52                         */
  53                 }
  54
  55                 void Error_CannotChangeAccessModifiers (TypeContainer parent, MethodInfo parent_method,
  56                                                         string name)
  57                 {
  58                         //
  59                         // FIXME: report the old/new permissions?
  60                         //
  61                         Report.Error (
  62                                 507, Location, parent.MakeName (Name) +
  63                                 ": can't change the access modifiers when overriding inherited " +
  64                                 "member `" + name + "'");
  65                 }
  66
  67                 //
  68                 // Performs various checks on the MethodInfo `mb' regarding the modifier flags
  69                 // that have been defined.
  70                 //
  71                 // `name' is the user visible name for reporting errors (this is used to
  72                 // provide the right name regarding method names and properties)
  73                 //
  74                 protected bool CheckMethodAgainstBase (TypeContainer parent, MethodAttributes my_attrs,
  75                                                        MethodInfo mb, string name)
  76                 {
  77                         bool ok = true;
  78
  79                         if ((ModFlags & Modifiers.OVERRIDE) != 0){
  80                                 // Now we check that the overriden method is not final
  81                                 if (mb.IsFinal) \r
  82                                 {
  83                                         Report.Error (30267, Location, parent.MakeName (Name) + " : cannot " +
  84                                                 "override inherited member `" + name +
  85                                                 "' because it is NotOverridable.");
  86                                         ok = false;
  87                                 }
  88                                 else if (!(mb.IsAbstract || mb.IsVirtual)){
  89                                         Report.Error (
  90                                                 31086, Location, parent.MakeName (Name) +
  91                                                 ": Cannot override inherited member `" +
  92                                                 name + "' because it is not " +
  93                                                 "declared as Overridable");
  94                                         ok = false;
  95                                 }
  96
  97                                 //
  98                                 // Check that the permissions are not being changed
  99                                 //
 100                                 MethodAttributes thisp = my_attrs & MethodAttributes.MemberAccessMask;
 101                                 MethodAttributes parentp = mb.Attributes & MethodAttributes.MemberAccessMask;
 102
 103                                 if (thisp != parentp){
 104                                         Error_CannotChangeAccessModifiers (parent, mb, name);
 105                                         ok = false;
 106                                 }
 107                         }
 108
 109                         if ((ModFlags & ( Modifiers.NEW | Modifiers.SHADOWS | Modifiers.OVERRIDE )) == 0) {
 110                                 if ((ModFlags & Modifiers.NONVIRTUAL) != 0)     {
 111                                         Report.Error (31088, Location,
 112                                                 parent.MakeName (Name) + " cannot " +
 113                                                 "be declared NotOverridable since this method is " +
 114                                                 "not marked as Overrides");
 115                                 }
 116                         }
 117
 118                         if (mb.IsAbstract) {
 119                                 if ((ModFlags & (Modifiers.OVERRIDE)) == 0)     {
 120                                         if (Name != "Finalize") {
 121                                                 Report.Error (
 122                                                         31404, Location,
 123                                                         name + " cannot Shadows the method " +
 124                                                         parent.MakeName (Name) + " since it is declared " +
 125                                                         "'MustOverride' in base class");
 126                                         }
 127                                 }
 128                         }
 129                         else if (mb.IsVirtual){
 130                                 if ((ModFlags & (Modifiers.NEW | Modifiers.OVERRIDE | Modifiers.SHADOWS)) == 0){
 131                                         if (Name != "Finalize"){
 132                                                 Report.Warning (
 133                                                         40005, 2, Location, parent.MakeName (Name) +
 134                                                         " shadows overridable member `" + name +
 135                                                         "'.  To make the current member override that " +
 136                                                         "implementation, add the overrides keyword." );
 137                                                 ModFlags |= Modifiers.SHADOWS;
 138                                         }
 139                                 }
 140                         }
 141                         else {
 142                                 if ((ModFlags & (Modifiers.NEW | Modifiers.OVERRIDE |
 143                                         Modifiers.SHADOWS)) == 0){
 144                                         if (Name != "Finalize"){
 145                                                 Report.Warning (
 146                                                         40004, 1, Location, "The keyword Shadows is required on " +
 147                                                         parent.MakeName (Name) + " because it hides " +
 148                                                         "inherited member `" + name + "'");
 149                                                 ModFlags |= Modifiers.SHADOWS;
 150                                         }
 151                                 }
 152                         }
 153
 154                         return ok;
 155                 }
 156
 157                 public abstract bool Define (TypeContainer parent);
 158
 159                 //
 160                 // Whehter is it ok to use an unsafe pointer in this type container
 161                 //
 162                 public bool UnsafeOK (DeclSpace parent)
 163                 {
 164                         //
 165                         // First check if this MemberCore modifier flags has unsafe set
 166                         //
 167                         if ((ModFlags & Modifiers.UNSAFE) != 0)
 168                                 return true;
 169
 170                         if (parent.UnsafeContext)
 171                                 return true;
 172
 173                         Expression.UnsafeError (Location);
 174                         return false;
 175                 }
 176         }
 177
 178         //
 179         // FIXME: This is temporary outside DeclSpace, because I have to fix a bug
 180         // in MCS that makes it fail the lookup for the enum
 181         //
 182
 183                 /// <summary>
 184                 ///   The result value from adding an declaration into
 185                 ///   a struct or a class
 186                 /// </summary>
 187                 public enum AdditionResult {
 188                         /// <summary>
 189                         /// The declaration has been successfully
 190                         /// added to the declation space.
 191                         /// </summary>
 192                         Success,
 193
 194                         /// <summary>
 195                         ///   The symbol has already been defined.
 196                         /// </summary>
 197                         NameExists,
 198
 199                         /// <summary>
 200                         ///   Returned if the declation being added to the
 201                         ///   name space clashes with its container name.
 202                         ///
 203                         ///   The only exceptions for this are constructors
 204                         ///   and static constructors
 205                         /// </summary>
 206                         EnclosingClash,
 207
 208                         /// <summary>
 209                         ///   Returned if a constructor was created (because syntactically
 210                         ///   it looked like a constructor) but was not (because the name
 211                         ///   of the method is not the same as the container class
 212                         /// </summary>
 213                         NotAConstructor,
 214
 215                         /// <summary>
 216                         ///   This is only used by static constructors to emit the
 217                         ///   error 111, but this error for other things really
 218                         ///   happens at another level for other functions.
 219                         /// </summary>
 220                         MethodExists
 221                 }
 222
 223         /// <summary>
 224         ///   Base class for structs, classes, enumerations and interfaces.
 225         /// </summary>
 226         /// <remarks>
 227         ///   They all create new declaration spaces.  This
 228         ///   provides the common foundation for managing those name
 229         ///   spaces.
 230         /// </remarks>
 231         public abstract class DeclSpace : MemberCore {
 232                 /// <summary>
 233                 ///   this points to the actual definition that is being
 234                 ///   created with System.Reflection.Emit
 235                 /// </summary>
 236                 public TypeBuilder TypeBuilder;
 237
 238                 /// <summary>
 239                 ///   This variable tracks whether we have Closed the type
 240                 /// </summary>
 241                 public bool Created = false;
 242
 243                 //
 244                 // This is the namespace in which this typecontainer
 245                 // was declared.  We use this to resolve names.
 246                 //
 247                 public Namespace Namespace;
 248
 249                 public Hashtable Cache = new Hashtable ();
 250
 251                 public string Basename;
 252
 253                 /// <summary>
 254                 ///   defined_names is used for toplevel objects
 255                 /// </summary>
 256                 protected Hashtable defined_names;
 257
 258                 TypeContainer parent;
 259
 260                 public DeclSpace (TypeContainer parent, string name, Location l)
 261                         : base (name, l)
 262                 {
 263                         Basename = name.Substring (1 + name.LastIndexOf ('.'));
 264                         defined_names = new Hashtable ();
 265                         this.parent = parent;
 266                 }
 267
 268                 /// <summary>
 269                 ///   Returns a status code based purely on the name
 270                 ///   of the member being added
 271                 /// </summary>
 272                 protected AdditionResult IsValid (string name)
 273                 {
 274                         if (name == Basename)
 275                                 return AdditionResult.EnclosingClash;
 276
 277                         if (defined_names.Contains (name))
 278                                 return AdditionResult.NameExists;
 279
 280                         return AdditionResult.Success;
 281                 }
 282
 283                 /// <summary>
 284                 ///   Introduce @name into this declaration space and
 285                 ///   associates it with the object @o.  Note that for
 286                 ///   methods this will just point to the first method. o
 287                 /// </summary>
 288                 protected void DefineName (string name, object o)
 289                 {
 290                         defined_names.Add (name, o);
 291                 }
 292
 293                 /// <summary>
 294                 ///   Returns the object associated with a given name in the declaration
 295                 ///   space.  This is the inverse operation of `DefineName'
 296                 /// </summary>
 297                 public object GetDefinition (string name)
 298                 {
 299                         return defined_names [name];
 300                 }
 301
 302                 bool in_transit = false;
 303
 304                 /// <summary>
 305                 ///   This function is used to catch recursive definitions
 306                 ///   in declarations.
 307                 /// </summary>
 308                 public bool InTransit {
 309                         get {
 310                                 return in_transit;
 311                         }
 312
 313                         set {
 314                                 in_transit = value;
 315                         }
 316                 }
 317
 318                 public TypeContainer Parent {
 319                         get {
 320                                 return parent;
 321                         }
 322                 }
 323
 324                 /// <summary>
 325                 ///   Looks up the alias for the name
 326                 /// </summary>
 327                 public string LookupAlias (string name)
 328                 {
 329                         return RootContext.SourceBeingCompiled.LookupAlias (name);
 330                 }
 331
 332                 //
 333                 // root_types contains all the types.  All TopLevel types
 334                 // hence have a parent that points to `root_types', that is
 335                 // why there is a non-obvious test down here.
 336                 //
 337                 public bool IsTopLevel {
 338                         get {
 339                                 if (parent != null){
 340                                         if (parent.parent == null)
 341                                                 return true;
 342                                 }
 343                                 return false;
 344                         }
 345                 }
 346
 347                 public virtual void CloseType ()
 348                 {
 349                         if (!Created){
 350                                 try {
 351                                         TypeBuilder.CreateType ();
 352                                 } catch {
 353                                         //
 354                                         // The try/catch is needed because
 355                                         // nested enumerations fail to load when they
 356                                         // are defined.
 357                                         //
 358                                         // Even if this is the right order (enumerations
 359                                         // declared after types).
 360                                         //
 361                                         // Note that this still creates the type and
 362                                         // it is possible to save it
 363                                 }
 364                                 Created = true;
 365                         }
 366                 }
 367
 368                 /// <remarks>
 369                 ///  Should be overriten by the appropriate declaration space
 370                 /// <remarks>
 371                 public abstract TypeBuilder DefineType ();
 372
 373                 /// <summary>
 374                 ///   Define all members, but don't apply any attributes or do anything which may
 375                 ///   access not-yet-defined classes.  This method also creates the MemberCache.
 376                 /// </summary>
 377                 public abstract bool DefineMembers (TypeContainer parent);
 378
 379                 //
 380                 // Whether this is an `unsafe context'
 381                 //
 382                 public bool UnsafeContext {
 383                         get {
 384                                 if ((ModFlags & Modifiers.UNSAFE) != 0)
 385                                         return true;
 386                                 if (parent != null)
 387                                         return parent.UnsafeContext;
 388                                 return false;
 389                         }
 390                 }
 391
 392                 public static string MakeFQN (string nsn, string name)
 393                 {
 394                         string prefix = (nsn == "" ? "" : nsn + ".");
 395
 396                         return prefix + name;
 397                 }
 398
 399                 EmitContext type_resolve_ec;
 400                 EmitContext GetTypeResolveEmitContext (TypeContainer parent, Location loc)
 401                 {
 402                         type_resolve_ec = new EmitContext (parent, this, loc, null, null, ModFlags, false);
 403                         type_resolve_ec.ResolvingTypeTree = true;
 404
 405                         return type_resolve_ec;
 406                 }
 407
 408                 // <summary>
 409                 //    Looks up the type, as parsed into the expression `e'
 410                 // </summary>
 411                 public Type ResolveType (Expression e, bool silent, Location loc)
 412                 {
 413                         if (type_resolve_ec == null)
 414                                 type_resolve_ec = GetTypeResolveEmitContext (parent, loc);
 415                         type_resolve_ec.loc = loc;
 416
 417                         int errors = Report.Errors;
 418                         Expression d = e.Resolve (type_resolve_ec, ResolveFlags.Type);
 419                         if (d == null || d.eclass != ExprClass.Type){
 420                                 if (!silent && errors == Report.Errors){
 421                                         Report.Error (246, loc, "Cannot find type `"+ e.ToString () +"'");
 422                                 }
 423                                 return null;
 424                         }
 425
 426                         return d.Type;
 427                 }
 428
 429                 // <summary>
 430                 //    Resolves the expression `e' for a type, and will recursively define
 431                 //    types.
 432                 // </summary>
 433                 public Expression ResolveTypeExpr (Expression e, bool silent, Location loc)
 434                 {
 435                         if (type_resolve_ec == null)
 436                                 type_resolve_ec = GetTypeResolveEmitContext (parent, loc);
 437
 438                         Expression d = e.Resolve (type_resolve_ec, ResolveFlags.Type);
 439                         if (d == null || d.eclass != ExprClass.Type){
 440                                 if (!silent){
 441                                         Report.Error (246, loc, "Cannot find type `"+ e +"'");
 442                                 }
 443                                 return null;
 444                         }
 445
 446                         return d;
 447                 }
 448
 449                 Type LookupInterfaceOrClass (string ns, string name, out bool error)
 450                 {
 451                         DeclSpace parent;
 452                         Type t;
 453
 454                         error = false;
 455                         name = MakeFQN (ns, name);
 456
 457                         t  = TypeManager.LookupType (name);
 458                         if (t != null)
 459                                 return t;
 460
 461                         parent = (DeclSpace) RootContext.Tree.Decls [name];
 462                         if (parent == null)
 463                                 return null;
 464
 465                         t = parent.DefineType ();
 466                         if (t == null){
 467                                 Report.Error (30256, Location, "Class definition is circular: `"+name+"'");
 468                                 error = true;
 469                                 return null;
 470                         }
 471                         return t;
 472                 }
 473
 474                 public static void Error_AmbiguousTypeReference (Location loc, string name, Type t1, Type t2)
 475                 {
 476                         Report.Error (104, loc,
 477                                       String.Format ("`{0}' is an ambiguous reference ({1} or {2}) ", name,
 478                                                      t1.FullName, t2.FullName));
 479                 }
 480
 481                 /// <summary>
 482                 ///   GetType is used to resolve type names at the DeclSpace level.
 483                 ///   Use this to lookup class/struct bases, interface bases or
 484                 ///   delegate type references
 485                 /// </summary>
 486                 ///
 487                 /// <remarks>
 488                 ///   Contrast this to LookupType which is used inside method bodies to
 489                 ///   lookup types that have already been defined.  GetType is used
 490                 ///   during the tree resolution process and potentially define
 491                 ///   recursively the type
 492                 /// </remarks>
 493                 public Type FindType (Location loc, string name)
 494                 {
 495                         Type t;
 496                         bool error;
 497
 498                         //
 499                         // For the case the type we are looking for is nested within this one
 500                         // or is in any base class
 501                         //
 502                         DeclSpace containing_ds = this;
 503
 504                         while (containing_ds != null){
 505                                 Type current_type = containing_ds.TypeBuilder;
 506
 507                                 while (current_type != null) {
 508                                         string pre = current_type.FullName;
 509
 510                                         t = LookupInterfaceOrClass (pre, name, out error);
 511                                         if (error)
 512                                                 return null;
 513
 514                                         if (t != null)
 515                                                 return t;
 516
 517                                         current_type = current_type.BaseType;
 518                                 }
 519                                 containing_ds = containing_ds.Parent;
 520                         }
 521
 522                         //
 523                         // Attempt to lookup the class on our namespace and all it's implicit parents
 524                         //
 525                         for (string ns = Namespace.Name; ns != null; ns = RootContext.ImplicitParent (ns)) {
 526
 527                                 t = LookupInterfaceOrClass (ns, name, out error);
 528                                 if (error)
 529                                         return null;
 530
 531                                 if (t != null)
 532                                         return t;
 533                         }
 534
 535                         //
 536                         // Attempt to do a direct unqualified lookup
 537                         //
 538                         t = LookupInterfaceOrClass ("", name, out error);
 539                         if (error)
 540                                 return null;
 541
 542                         if (t != null)
 543                                 return t;
 544
 545                         //
 546                         // Attempt to lookup the class on any of the `using'
 547                         // namespaces
 548                         //
 549
 550                         for (Namespace ns = Namespace; ns != null; ns = ns.Parent){
 551
 552                                 t = LookupInterfaceOrClass (ns.Name, name, out error);
 553                                 if (error)
 554                                         return null;
 555
 556                                 if (t != null)
 557                                         return t;
 558
 559                                 //
 560                                 // Now check the using clause list
 561                                 //
 562                                 ICollection imports_list = RootContext.SourceBeingCompiled.ImportsTable;\r
 563 \r
 564                                 if (imports_list == null)\r
 565                                         continue;\r
 566
 567                                 Type match = null;
 568                                 foreach (SourceBeingCompiled.ImportsEntry ue in imports_list){
 569                                         match = LookupInterfaceOrClass (ue.Name, name, out error);
 570                                         if (error)
 571                                                 return null;
 572
 573                                         if (match != null){
 574                                                 if (t != null){
 575                                                         Error_AmbiguousTypeReference (loc, name, t, match);
 576                                                         return null;
 577                                                 }
 578
 579                                                 t = match;
 580                                                 ue.Used = true;
 581                                         }
 582                                 }
 583                                 if (t != null)
 584                                         return t;
 585                         }
 586
 587                         //Report.Error (246, Location, "Can not find type `"+name+"'");
 588                         return null;
 589                 }
 590
 591                 /// <remarks>
 592                 ///   This function is broken and not what you're looking for.  It should only
 593                 ///   be used while the type is still being created since it doesn't use the cache
 594                 ///   and relies on the filter doing the member name check.
 595                 /// </remarks>
 596                 public abstract MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 597                                                         MemberFilter filter, object criteria);
 598
 599                 /// <remarks>
 600                 ///   If we have a MemberCache, return it.  This property may return null if the
 601                 ///   class doesn't have a member cache or while it's still being created.
 602                 /// </remarks>
 603                 public abstract MemberCache MemberCache {
 604                         get;
 605                 }
 606         }
 607
 608         /// <summary>
 609         ///   This is a readonly list of MemberInfo's.
 610         /// </summary>
 611         public class MemberList : IList {
 612                 public readonly IList List;
 613                 int count;
 614
 615                 /// <summary>
 616                 ///   Create a new MemberList from the given IList.
 617                 /// </summary>
 618                 public MemberList (IList list)
 619                 {
 620                         if (list != null)
 621                                 this.List = list;
 622                         else
 623                                 this.List = new ArrayList ();
 624                         count = List.Count;
 625                 }
 626
 627                 /// <summary>
 628                 ///   Concatenate the ILists `first' and `second' to a new MemberList.
 629                 /// </summary>
 630                 public MemberList (IList first, IList second)
 631                 {
 632                         ArrayList list = new ArrayList ();
 633                         list.AddRange (first);
 634                         list.AddRange (second);
 635                         count = list.Count;
 636                         List = list;
 637                 }
 638
 639                 public static readonly MemberList Empty = new MemberList (new ArrayList ());
 640
 641                 /// <summary>
 642                 ///   Cast the MemberList into a MemberInfo[] array.
 643                 /// </summary>
 644                 /// <remarks>
 645                 ///   This is an expensive operation, only use it if it's really necessary.
 646                 /// </remarks>
 647                 public static explicit operator MemberInfo [] (MemberList list)
 648                 {
 649                         Timer.StartTimer (TimerType.MiscTimer);
 650                         MemberInfo [] result = new MemberInfo [list.Count];
 651                         list.CopyTo (result, 0);
 652                         Timer.StopTimer (TimerType.MiscTimer);
 653                         return result;
 654                 }
 655
 656                 // ICollection
 657
 658                 public int Count {
 659                         get {
 660                                 return count;
 661                         }
 662                 }
 663
 664                 public bool IsSynchronized {
 665                         get {
 666                                 return List.IsSynchronized;
 667                         }
 668                 }
 669
 670                 public object SyncRoot {
 671                         get {
 672                                 return List.SyncRoot;
 673                         }
 674                 }
 675
 676                 public void CopyTo (Array array, int index)
 677                 {
 678                         List.CopyTo (array, index);
 679                 }
 680
 681                 // IEnumerable
 682
 683                 public IEnumerator GetEnumerator ()
 684                 {
 685                         return List.GetEnumerator ();
 686                 }
 687
 688                 // IList
 689
 690                 public bool IsFixedSize {
 691                         get {
 692                                 return true;
 693                         }
 694                 }
 695
 696                 public bool IsReadOnly {
 697                         get {
 698                                 return true;
 699                         }
 700                 }
 701
 702                 object IList.this [int index] {
 703                         get {
 704                                 return List [index];
 705                         }
 706
 707                         set {
 708                                 throw new NotSupportedException ();
 709                         }
 710                 }
 711
 712                 // FIXME: try to find out whether we can avoid the cast in this indexer.
 713                 public MemberInfo this [int index] {
 714                         get {
 715                                 return (MemberInfo) List [index];
 716                         }
 717                 }
 718
 719                 public int Add (object value)
 720                 {
 721                         throw new NotSupportedException ();
 722                 }
 723
 724                 public void Clear ()
 725                 {
 726                         throw new NotSupportedException ();
 727                 }
 728
 729                 public bool Contains (object value)
 730                 {
 731                         return List.Contains (value);
 732                 }
 733
 734                 public int IndexOf (object value)
 735                 {
 736                         return List.IndexOf (value);
 737                 }
 738
 739                 public void Insert (int index, object value)
 740                 {
 741                         throw new NotSupportedException ();
 742                 }
 743
 744                 public void Remove (object value)
 745                 {
 746                         throw new NotSupportedException ();
 747                 }
 748
 749                 public void RemoveAt (int index)
 750                 {
 751                         throw new NotSupportedException ();
 752                 }
 753         }
 754
 755         /// <summary>
 756         ///   This interface is used to get all members of a class when creating the
 757         ///   member cache.  It must be implemented by all DeclSpace derivatives which
 758         ///   want to support the member cache and by TypeHandle to get caching of
 759         ///   non-dynamic types.
 760         /// </summary>
 761         public interface IMemberContainer {
 762                 /// <summary>
 763                 ///   The name of the IMemberContainer.  This is only used for
 764                 ///   debugging purposes.
 765                 /// </summary>
 766                 string Name {
 767                         get;
 768                 }
 769
 770                 /// <summary>
 771                 ///   The type of this IMemberContainer.
 772                 /// </summary>
 773                 Type Type {
 774                         get;
 775                 }
 776
 777                 /// <summary>
 778                 ///   Returns the IMemberContainer of the parent class or null if this
 779                 ///   is an interface or TypeManger.object_type.
 780                 ///   This is used when creating the member cache for a class to get all
 781                 ///   members from the parent class.
 782                 /// </summary>
 783                 IMemberContainer Parent {
 784                         get;
 785                 }
 786
 787                 /// <summary>
 788                 ///   Whether this is an interface.
 789                 /// </summary>
 790                 bool IsInterface {
 791                         get;
 792                 }
 793
 794                 /// <summary>
 795                 ///   Returns all members of this class with the corresponding MemberTypes
 796                 ///   and BindingFlags.
 797                 /// </summary>
 798                 /// <remarks>
 799                 ///   When implementing this method, make sure not to return any inherited
 800                 ///   members and check the MemberTypes and BindingFlags properly.
 801                 ///   Unfortunately, System.Reflection is lame and doesn't provide a way to
 802                 ///   get the BindingFlags (static/non-static,public/non-public) in the
 803                 ///   MemberInfo class, but the cache needs this information.  That's why
 804                 ///   this method is called multiple times with different BindingFlags.
 805                 /// </remarks>
 806                 MemberList GetMembers (MemberTypes mt, BindingFlags bf);
 807
 808                 /// <summary>
 809                 ///   Return the container's member cache.
 810                 /// </summary>
 811                 MemberCache MemberCache {
 812                         get;
 813                 }
 814         }
 815
 816         /// <summary>
 817         ///   The MemberCache is used by dynamic and non-dynamic types to speed up
 818         ///   member lookups.  It has a member name based hash table; it maps each member
 819         ///   name to a list of CacheEntry objects.  Each CacheEntry contains a MemberInfo
 820         ///   and the BindingFlags that were initially used to get it.  The cache contains
 821         ///   all members of the current class and all inherited members.  If this cache is
 822         ///   for an interface types, it also contains all inherited members.
 823         ///
 824         ///   There are two ways to get a MemberCache:
 825         ///   * if this is a dynamic type, lookup the corresponding DeclSpace and then
 826         ///     use the DeclSpace.MemberCache property.
 827         ///   * if this not a dynamic type, call TypeHandle.GetTypeHandle() to get a
 828         ///     TypeHandle instance for the type and then use TypeHandle.MemberCache.
 829         /// </summary>
 830         public class MemberCache {
 831                 public readonly IMemberContainer Container;
 832                 protected CaseInsensitiveHashtable member_hash;
 833                 protected CaseInsensitiveHashtable method_hash;
 834                 protected CaseInsensitiveHashtable interface_hash;
 835
 836                 /// <summary>
 837                 ///   Create a new MemberCache for the given IMemberContainer `container'.
 838                 /// </summary>
 839                 public MemberCache (IMemberContainer container)
 840                 {
 841                         this.Container = container;
 842
 843                         Timer.IncrementCounter (CounterType.MemberCache);
 844                         Timer.StartTimer (TimerType.CacheInit);
 845
 846                         interface_hash = new CaseInsensitiveHashtable ();
 847
 848                         // If we have a parent class (we have a parent class unless we're
 849                         // TypeManager.object_type), we deep-copy its MemberCache here.
 850                         if (Container.Parent != null)
 851                                 member_hash = SetupCache (Container.Parent.MemberCache);
 852                         else if (Container.IsInterface)
 853                                 member_hash = SetupCacheForInterface ();
 854                         else
 855                                 member_hash = new CaseInsensitiveHashtable ();
 856
 857                         // If this is neither a dynamic type nor an interface, create a special
 858                         // method cache with all declared and inherited methods.
 859                         Type type = container.Type;
 860                         if (!(type is TypeBuilder) && !type.IsInterface) {
 861                                 method_hash = new CaseInsensitiveHashtable ();
 862                                 AddMethods (type);
 863                         }
 864
 865                         // Add all members from the current class.
 866                         AddMembers (Container);
 867
 868                         Timer.StopTimer (TimerType.CacheInit);
 869                 }
 870
 871                 /// <summary>
 872                 ///   Bootstrap this member cache by doing a deep-copy of our parent.
 873                 /// </summary>
 874                 CaseInsensitiveHashtable SetupCache (MemberCache parent)
 875                 {
 876                         CaseInsensitiveHashtable hash = new CaseInsensitiveHashtable ();
 877
 878                         IDictionaryEnumerator it = parent.member_hash.GetEnumerator ();
 879                         while (it.MoveNext ()) {
 880                                 hash [it.Key] = ((ArrayList) it.Value).Clone ();
 881                         }
 882
 883                         return hash;
 884                 }
 885
 886                 void AddInterfaces (MemberCache parent)
 887                 {
 888                         foreach (Type iface in parent.interface_hash.Keys) {
 889                                 if (!interface_hash.Contains (iface))
 890                                         interface_hash.Add (iface, true);
 891                         }
 892                 }
 893
 894                 /// <summary>
 895                 ///   Add the contents of `new_hash' to `hash'.
 896                 /// </summary>
 897                 void AddHashtable (Hashtable hash, Hashtable new_hash)
 898                 {
 899                         IDictionaryEnumerator it = new_hash.GetEnumerator ();
 900                         while (it.MoveNext ()) {
 901                                 ArrayList list = (ArrayList) hash [it.Key];
 902                                 if (list != null)
 903                                         list.AddRange ((ArrayList) it.Value);
 904                                 else
 905                                         hash [it.Key] = ((ArrayList) it.Value).Clone ();
 906                         }
 907                 }
 908
 909                 /// <summary>
 910                 ///   Bootstrap the member cache for an interface type.
 911                 ///   Type.GetMembers() won't return any inherited members for interface types,
 912                 ///   so we need to do this manually.  Interfaces also inherit from System.Object.
 913                 /// </summary>
 914                 CaseInsensitiveHashtable SetupCacheForInterface ()
 915                 {
 916                         CaseInsensitiveHashtable hash = SetupCache (TypeHandle.ObjectType.MemberCache);
 917                         Type [] ifaces = TypeManager.GetInterfaces (Container.Type);
 918
 919                         foreach (Type iface in ifaces) {
 920                                 if (interface_hash.Contains (iface))
 921                                         continue;
 922                                 interface_hash.Add (iface, true);
 923
 924                                 IMemberContainer iface_container =
 925                                         TypeManager.LookupMemberContainer (iface);
 926
 927                                 MemberCache iface_cache = iface_container.MemberCache;
 928                                 AddHashtable (hash, iface_cache.member_hash);
 929                                 AddInterfaces (iface_cache);
 930                         }
 931
 932                         return hash;
 933                 }
 934
 935                 /// <summary>
 936                 ///   Add all members from class `container' to the cache.
 937                 /// </summary>
 938                 void AddMembers (IMemberContainer container)
 939                 {
 940                         // We need to call AddMembers() with a single member type at a time
 941                         // to get the member type part of CacheEntry.EntryType right.
 942                         AddMembers (MemberTypes.Constructor, container);
 943                         AddMembers (MemberTypes.Field, container);
 944                         AddMembers (MemberTypes.Method, container);
 945                         AddMembers (MemberTypes.Property, container);
 946                         AddMembers (MemberTypes.Event, container);
 947                         // Nested types are returned by both Static and Instance searches.
 948                         AddMembers (MemberTypes.NestedType,
 949                                     BindingFlags.Static | BindingFlags.Public, container);
 950                         AddMembers (MemberTypes.NestedType,
 951                                     BindingFlags.Static | BindingFlags.NonPublic, container);
 952                 }
 953
 954                 void AddMembers (MemberTypes mt, IMemberContainer container)
 955                 {
 956                         AddMembers (mt, BindingFlags.Static | BindingFlags.Public, container);
 957                         AddMembers (mt, BindingFlags.Static | BindingFlags.NonPublic, container);
 958                         AddMembers (mt, BindingFlags.Instance | BindingFlags.Public, container);
 959                         AddMembers (mt, BindingFlags.Instance | BindingFlags.NonPublic, container);
 960                 }
 961
 962                 /// <summary>
 963                 ///   Add all members from class `container' with the requested MemberTypes and
 964                 ///   BindingFlags to the cache.  This method is called multiple times with different
 965                 ///   MemberTypes and BindingFlags.
 966                 /// </summary>
 967                 void AddMembers (MemberTypes mt, BindingFlags bf, IMemberContainer container)
 968                 {
 969                         MemberList members = container.GetMembers (mt, bf);
 970                         BindingFlags new_bf = (container == Container) ?
 971                                 bf | BindingFlags.DeclaredOnly : bf;
 972
 973                         foreach (MemberInfo member in members) {
 974                                 string name = member.Name;
 975
 976                                 // We use a name-based hash table of ArrayList's.
 977                                 ArrayList list = (ArrayList) member_hash [name];
 978                                 if (list == null) {
 979                                         list = new ArrayList ();
 980                                         member_hash.Add (name, list);
 981                                 }
 982
 983                                 // When this method is called for the current class, the list will
 984                                 // already contain all inherited members from our parent classes.
 985                                 // We cannot add new members in front of the list since this'd be an
 986                                 // expensive operation, that's why the list is sorted in reverse order
 987                                 // (ie. members from the current class are coming last).
 988                                 list.Add (new CacheEntry (container, member, mt, bf));
 989                         }
 990                 }
 991
 992                 /// <summary>
 993                 ///   Add all declared and inherited methods from class `type' to the method cache.
 994                 /// </summary>
 995                 void AddMethods (Type type)
 996                 {
 997                         AddMethods (BindingFlags.Static | BindingFlags.Public, type);
 998                         AddMethods (BindingFlags.Static | BindingFlags.NonPublic, type);
 999                         AddMethods (BindingFlags.Instance | BindingFlags.Public, type);
1000                         AddMethods (BindingFlags.Instance | BindingFlags.NonPublic, type);
1001                 }
1002
1003                 void AddMethods (BindingFlags bf, Type type)
1004                 {
1005                         MemberInfo [] members = type.GetMethods (bf);
1006
1007                         foreach (MethodBase member in members) {
1008                                 string name = member.Name;
1009
1010                                 // Varargs methods aren't allowed in C# code.
1011                                 if ((member.CallingConvention & CallingConventions.VarArgs) != 0)
1012                                         continue;
1013
1014                                 // We use a name-based hash table of ArrayList's.
1015                                 ArrayList list = (ArrayList) method_hash [name];
1016                                 if (list == null) {
1017                                         list = new ArrayList ();
1018                                         method_hash.Add (name, list);
1019                                 }
1020
1021                                 // Unfortunately, the elements returned by Type.GetMethods() aren't
1022                                 // sorted so we need to do this check for every member.
1023                                 BindingFlags new_bf = bf;
1024                                 if (member.DeclaringType == type)
1025                                         new_bf |= BindingFlags.DeclaredOnly;
1026
1027                                 list.Add (new CacheEntry (Container, member, MemberTypes.Method, new_bf));
1028                         }
1029                 }
1030
1031                 /// <summary>
1032                 ///   Compute and return a appropriate `EntryType' magic number for the given
1033                 ///   MemberTypes and BindingFlags.
1034                 /// </summary>
1035                 protected static EntryType GetEntryType (MemberTypes mt, BindingFlags bf)
1036                 {
1037                         EntryType type = EntryType.None;
1038
1039                         if ((mt & MemberTypes.Constructor) != 0)
1040                                 type |= EntryType.Constructor;
1041                         if ((mt & MemberTypes.Event) != 0)
1042                                 type |= EntryType.Event;
1043                         if ((mt & MemberTypes.Field) != 0)
1044                                 type |= EntryType.Field;
1045                         if ((mt & MemberTypes.Method) != 0)
1046                                 type |= EntryType.Method;
1047                         if ((mt & MemberTypes.Property) != 0)
1048                                 type |= EntryType.Property;
1049                         // Nested types are returned by static and instance searches.
1050                         if ((mt & MemberTypes.NestedType) != 0)
1051                                 type |= EntryType.NestedType | EntryType.Static | EntryType.Instance;
1052
1053                         if ((bf & BindingFlags.Instance) != 0)
1054                                 type |= EntryType.Instance;
1055                         if ((bf & BindingFlags.Static) != 0)
1056                                 type |= EntryType.Static;
1057                         if ((bf & BindingFlags.Public) != 0)
1058                                 type |= EntryType.Public;
1059                         if ((bf & BindingFlags.NonPublic) != 0)
1060                                 type |= EntryType.NonPublic;
1061                         if ((bf & BindingFlags.DeclaredOnly) != 0)
1062                                 type |= EntryType.Declared;
1063
1064                         return type;
1065                 }
1066
1067                 /// <summary>
1068                 ///   The `MemberTypes' enumeration type is a [Flags] type which means that it may
1069                 ///   denote multiple member types.  Returns true if the given flags value denotes a
1070                 ///   single member types.
1071                 /// </summary>
1072                 public static bool IsSingleMemberType (MemberTypes mt)
1073                 {
1074                         switch (mt) {
1075                         case MemberTypes.Constructor:
1076                         case MemberTypes.Event:
1077                         case MemberTypes.Field:
1078                         case MemberTypes.Method:
1079                         case MemberTypes.Property:
1080                         case MemberTypes.NestedType:
1081                                 return true;
1082
1083                         default:
1084                                 return false;
1085                         }
1086                 }
1087
1088                 /// <summary>
1089                 ///   We encode the MemberTypes and BindingFlags of each members in a "magic"
1090                 ///   number to speed up the searching process.
1091                 /// </summary>
1092                 [Flags]
1093                 protected enum EntryType {
1094                         None            = 0x000,
1095
1096                         Instance        = 0x001,
1097                         Static          = 0x002,
1098                         MaskStatic      = Instance|Static,
1099
1100                         Public          = 0x004,
1101                         NonPublic       = 0x008,
1102                         MaskProtection  = Public|NonPublic,
1103
1104                         Declared        = 0x010,
1105
1106                         Constructor     = 0x020,
1107                         Event           = 0x040,
1108                         Field           = 0x080,
1109                         Method          = 0x100,
1110                         Property        = 0x200,
1111                         NestedType      = 0x400,
1112
1113                         MaskType        = Constructor|Event|Field|Method|Property|NestedType
1114                 }
1115
1116                 protected struct CacheEntry {
1117                         public readonly IMemberContainer Container;
1118                         public readonly EntryType EntryType;
1119                         public readonly MemberInfo Member;
1120
1121                         public CacheEntry (IMemberContainer container, MemberInfo member,
1122                                            MemberTypes mt, BindingFlags bf)
1123                         {
1124                                 this.Container = container;
1125                                 this.Member = member;
1126                                 this.EntryType = GetEntryType (mt, bf);
1127                         }
1128                 }
1129
1130                 /// <summary>
1131                 ///   This is called each time we're walking up one level in the class hierarchy
1132                 ///   and checks whether we can abort the search since we've already found what
1133                 ///   we were looking for.
1134                 /// </summary>
1135                 protected bool DoneSearching (ArrayList list)
1136                 {
1137                         //
1138                         // We've found exactly one member in the current class and it's not
1139                         // a method or constructor.
1140                         //
1141                         if (list.Count == 1 && !(list [0] is MethodBase))
1142                                 return true;
1143
1144                         //
1145                         // Multiple properties: we query those just to find out the indexer
1146                         // name
1147                         //
1148                         if ((list.Count > 0) && (list [0] is PropertyInfo))
1149                                 return true;
1150
1151                         return false;
1152                 }
1153
1154                 /// <summary>
1155                 ///   Looks up members with name `name'.  If you provide an optional
1156                 ///   filter function, it'll only be called with members matching the
1157                 ///   requested member name.
1158                 ///
1159                 ///   This method will try to use the cache to do the lookup if possible.
1160                 ///
1161                 ///   Unlike other FindMembers implementations, this method will always
1162                 ///   check all inherited members - even when called on an interface type.
1163                 ///
1164                 ///   If you know that you're only looking for methods, you should use
1165                 ///   MemberTypes.Method alone since this speeds up the lookup a bit.
1166                 ///   When doing a method-only search, it'll try to use a special method
1167                 ///   cache (unless it's a dynamic type or an interface) and the returned
1168                 ///   MemberInfo's will have the correct ReflectedType for inherited methods.
1169                 ///   The lookup process will automatically restart itself in method-only
1170                 ///   search mode if it discovers that it's about to return methods.
1171                 /// </summary>
1172                 public MemberList FindMembers (MemberTypes mt, BindingFlags bf, string name,
1173                                                MemberFilter filter, object criteria)
1174                 {
1175                         bool declared_only = (bf & BindingFlags.DeclaredOnly) != 0;
1176                         bool method_search = mt == MemberTypes.Method;
1177                         // If we have a method cache and we aren't already doing a method-only search,
1178                         // then we restart a method search if the first match is a method.
1179                         bool do_method_search = !method_search && (method_hash != null);
1180 bf |= BindingFlags.IgnoreCase;
1181                         ArrayList applicable;
1182
1183                         // If this is a method-only search, we try to use the method cache if
1184                         // possible; a lookup in the method cache will return a MemberInfo with
1185                         // the correct ReflectedType for inherited methods.
1186                         if (method_search && (method_hash != null))
1187                                 applicable = (ArrayList) method_hash [name];
1188                         else
1189                                 applicable = (ArrayList) member_hash [name];
1190
1191                         if (applicable == null)
1192                                 return MemberList.Empty;
1193
1194                         ArrayList list = new ArrayList ();
1195
1196                         Timer.StartTimer (TimerType.CachedLookup);
1197
1198                         EntryType type = GetEntryType (mt, bf);
1199
1200                         IMemberContainer current = Container;
1201
1202                         // `applicable' is a list of all members with the given member name `name'
1203                         // in the current class and all its parent classes.  The list is sorted in
1204                         // reverse order due to the way how the cache is initialy created (to speed
1205                         // things up, we're doing a deep-copy of our parent).
1206
1207                         for (int i = applicable.Count-1; i >= 0; i--) {
1208                                 CacheEntry entry = (CacheEntry) applicable [i];
1209
1210                                 // This happens each time we're walking one level up in the class
1211                                 // hierarchy.  If we're doing a DeclaredOnly search, we must abort
1212                                 // the first time this happens (this may already happen in the first
1213                                 // iteration of this loop if there are no members with the name we're
1214                                 // looking for in the current class).
1215                                 if (entry.Container != current) {
1216                                         if (declared_only || DoneSearching (list))
1217                                                 break;
1218
1219                                         current = entry.Container;
1220                                 }
1221
1222                                 // Is the member of the correct type ?
1223                                 if ((entry.EntryType & type & EntryType.MaskType) == 0)
1224                                         continue;
1225
1226                                 // Is the member static/non-static ?
1227                                 if ((entry.EntryType & type & EntryType.MaskStatic) == 0)
1228                                         continue;
1229
1230                                 // Apply the filter to it.
1231                                 if (filter (entry.Member, criteria)) {
1232                                         if ((entry.EntryType & EntryType.MaskType) != EntryType.Method)
1233                                                 do_method_search = false;
1234                                         list.Add (entry.Member);
1235                                 }
1236                         }
1237
1238                         Timer.StopTimer (TimerType.CachedLookup);
1239
1240                         // If we have a method cache and we aren't already doing a method-only
1241                         // search, we restart in method-only search mode if the first match is
1242                         // a method.  This ensures that we return a MemberInfo with the correct
1243                         // ReflectedType for inherited methods.
1244                         if (do_method_search && (list.Count > 0))
1245                                 return FindMembers (MemberTypes.Method, bf, name, filter, criteria);
1246
1247                         return new MemberList (list);
1248                 }
1249         }
1250 }