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