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 : Attributable
  25         {
  26                 /// <summary>
  27                 ///   Public name
  28                 /// </summary>
  29                 public string Name;
  30
  31                 /// <summary>
  32                 ///   Modifier flags that the user specified in the source code
  33                 /// </summary>
  34                 public int ModFlags;
  35
  36                 /// <summary>
  37                 ///   Location where this declaration happens
  38                 /// </summary>
  39                 public readonly Location Location;
  40
  41                 public MemberCore (string name, Attributes attrs, Location loc)
  42                         : base (attrs)
  43                 {
  44                         Name = name;
  45                         Location = loc;
  46                 }
  47
  48                 protected void WarningNotHiding (TypeContainer parent)
  49                 {
  50                         /*Report.Warning (
  51                                 109, Location,
  52                                 "The member " + parent.MakeName (Name) + " does not hide an " +
  53                                 "inherited member.  The keyword new is not required");
  54                         */
  55                 }
  56
  57                 void Error_CannotChangeAccessModifiers (TypeContainer parent, MethodInfo parent_method,
  58                                                         string name)
  59                 {
  60                         //
  61                         // FIXME: report the old/new permissions?
  62                         //
  63                         Report.Error (
  64                                 507, Location, parent.MakeName (Name) +
  65                                 ": can't change the access modifiers when overriding inherited " +
  66                                 "member `" + name + "'");
  67                 }
  68
  69                 //
  70                 // Performs various checks on the MethodInfo `mb' regarding the modifier flags
  71                 // that have been defined.
  72                 //
  73                 // `name' is the user visible name for reporting errors (this is used to
  74                 // provide the right name regarding method names and properties)
  75                 //
  76                 protected bool CheckMethodAgainstBase (TypeContainer parent, MethodAttributes my_attrs,
  77                                                        MethodInfo mb, string name)
  78                 {
  79                         bool ok = true;
  80
  81                         if ((ModFlags & Modifiers.OVERRIDE) != 0){
  82                                 // Now we check that the overriden method is not final
  83                                 if (mb.IsFinal)
  84                                 {
  85                                         Report.Error (30267, Location, parent.MakeName (Name) + " : cannot " +
  86                                                 "override inherited member `" + name +
  87                                                 "' because it is NotOverridable.");
  88                                         ok = false;
  89                                 }
  90                                 else if (!(mb.IsAbstract || mb.IsVirtual)){
  91                                         Report.Error (
  92                                                 31086, Location, parent.MakeName (Name) +
  93                                                 ": Cannot override inherited member `" +
  94                                                 name + "' because it is not " +
  95                                                 "declared as Overridable");
  96                                         ok = false;
  97                                 }
  98
  99                                 //
 100                                 // Check that the permissions are not being changed
 101                                 //
 102                                 MethodAttributes thisp = my_attrs & MethodAttributes.MemberAccessMask;
 103                                 MethodAttributes parentp = mb.Attributes & MethodAttributes.MemberAccessMask;
 104
 105                                 if (thisp != parentp){
 106                                         Error_CannotChangeAccessModifiers (parent, mb, name);
 107                                         ok = false;
 108                                 }
 109                         }
 110
 111                         if ((ModFlags & ( Modifiers.NEW | Modifiers.SHADOWS | Modifiers.OVERRIDE )) == 0) {
 112                                 if ((ModFlags & Modifiers.NONVIRTUAL) != 0)     {
 113                                         Report.Error (31088, Location,
 114                                                 parent.MakeName (Name) + " cannot " +
 115                                                 "be declared NotOverridable since this method is " +
 116                                                 "not marked as Overrides");
 117                                 }
 118                         }
 119
 120                         if (mb.IsAbstract) {
 121                                 if ((ModFlags & (Modifiers.OVERRIDE)) == 0)     {
 122                                         if (Name != "Finalize") {
 123                                                 Report.Error (
 124                                                         31404, Location,
 125                                                         name + " cannot Shadows the method " +
 126                                                         parent.MakeName (Name) + " since it is declared " +
 127                                                         "'MustOverride' in base class");
 128                                         }
 129                                 }
 130                         }
 131                         else if (mb.IsVirtual){
 132                                 if ((ModFlags & (Modifiers.NEW | Modifiers.OVERRIDE | Modifiers.SHADOWS)) == 0){
 133                                         if (Name != "Finalize"){
 134                                                 Report.Warning (
 135                                                         40005, 2, Location, parent.MakeName (Name) +
 136                                                         " shadows overridable member `" + name +
 137                                                         "'.  To make the current member override that " +
 138                                                         "implementation, add the overrides keyword." );
 139                                                 ModFlags |= Modifiers.SHADOWS;
 140                                         }
 141                                 }
 142                         }
 143                         else {
 144                                 if ((ModFlags & (Modifiers.NEW | Modifiers.OVERRIDE |
 145                                         Modifiers.SHADOWS)) == 0){
 146                                         if (Name != "Finalize"){
 147                                                 Report.Warning (
 148                                                         40004, 1, Location, "The keyword Shadows is required on " +
 149                                                         parent.MakeName (Name) + " because it hides " +
 150                                                         "inherited member `" + name + "'");
 151                                                 ModFlags |= Modifiers.SHADOWS;
 152                                         }
 153                                 }
 154                         }
 155
 156                         return ok;
 157                 }
 158
 159                 public abstract bool Define (TypeContainer parent);
 160
 161                 //
 162                 // Whehter is it ok to use an unsafe pointer in this type container
 163                 //
 164                 public bool UnsafeOK (DeclSpace parent)
 165                 {
 166                         //
 167                         // First check if this MemberCore modifier flags has unsafe set
 168                         //
 169                         if ((ModFlags & Modifiers.UNSAFE) != 0)
 170                                 return true;
 171
 172                         if (parent.UnsafeContext)
 173                                 return true;
 174
 175                         Expression.UnsafeError (Location);
 176                         return false;
 177                 }
 178         }
 179
 180         //
 181         // FIXME: This is temporary outside DeclSpace, because I have to fix a bug
 182         // in MCS that makes it fail the lookup for the enum
 183         //
 184
 185                 /// <summary>
 186                 ///   The result value from adding an declaration into
 187                 ///   a struct or a class
 188                 /// </summary>
 189                 public enum AdditionResult {
 190                         /// <summary>
 191                         /// The declaration has been successfully
 192                         /// added to the declation space.
 193                         /// </summary>
 194                         Success,
 195
 196                         /// <summary>
 197                         ///   The symbol has already been defined.
 198                         /// </summary>
 199                         NameExists,
 200
 201                         /// <summary>
 202                         ///   Returned if the declation being added to the
 203                         ///   name space clashes with its container name.
 204                         ///
 205                         ///   The only exceptions for this are constructors
 206                         ///   and static constructors
 207                         /// </summary>
 208                         EnclosingClash,
 209
 210                         /// <summary>
 211                         ///   Returned if a constructor was created (because syntactically
 212                         ///   it looked like a constructor) but was not (because the name
 213                         ///   of the method is not the same as the container class
 214                         /// </summary>
 215                         NotAConstructor,
 216
 217                         /// <summary>
 218                         ///   This is only used by static constructors to emit the
 219                         ///   error 111, but this error for other things really
 220                         ///   happens at another level for other functions.
 221                         /// </summary>
 222                         MethodExists
 223                 }
 224
 225         /// <summary>
 226         ///   Base class for structs, classes, enumerations and interfaces.
 227         /// </summary>
 228         /// <remarks>
 229         ///   They all create new declaration spaces.  This
 230         ///   provides the common foundation for managing those name
 231         ///   spaces.
 232         /// </remarks>
 233         public abstract class DeclSpace : MemberCore {
 234                 /// <summary>
 235                 ///   this points to the actual definition that is being
 236                 ///   created with System.Reflection.Emit
 237                 /// </summary>
 238                 public TypeBuilder TypeBuilder;
 239
 240                 /// <summary>
 241                 ///   This variable tracks whether we have Closed the type
 242                 /// </summary>
 243                 public bool Created = false;
 244
 245                 //
 246                 // This is the namespace in which this typecontainer
 247                 // was declared.  We use this to resolve names.
 248                 //
 249                 public Namespace Namespace;
 250
 251                 public Hashtable Cache = new Hashtable ();
 252
 253                 public string Basename;
 254
 255                 /// <summary>
 256                 ///   defined_names is used for toplevel objects
 257                 /// </summary>
 258                 protected Hashtable defined_names;
 259
 260                 TypeContainer parent;
 261
 262                 public DeclSpace (TypeContainer parent, string name, Attributes attrs, Location l)
 263                         : base (name, attrs, l)
 264                 {
 265                         Basename = name.Substring (1 + name.LastIndexOf ('.'));
 266                         defined_names = new Hashtable ();
 267                         this.parent = parent;
 268                 }
 269
 270                 /// <summary>
 271                 ///   Returns a status code based purely on the name
 272                 ///   of the member being added
 273                 /// </summary>
 274                 protected AdditionResult IsValid (string name)
 275                 {
 276                         if (name == Basename)
 277                                 return AdditionResult.EnclosingClash;
 278
 279                         if (defined_names.Contains (name))
 280                                 return AdditionResult.NameExists;
 281
 282                         return AdditionResult.Success;
 283                 }
 284
 285                 /// <summary>
 286                 ///   Introduce @name into this declaration space and
 287                 ///   associates it with the object @o.  Note that for
 288                 ///   methods this will just point to the first method. o
 289                 /// </summary>
 290                 protected void DefineName (string name, object o)
 291                 {
 292                         try {
 293                                 defined_names.Add (name, o);
 294                         }
 295                         catch (ArgumentException exp) {
 296                                 Report.Error (30260, /*Location,*/
 297                                         "More than one defination with same name '" + name +
 298                                         "' is found in the container '" + Name + "'");
 299                     }
 300
 301                 }
 302
 303                 /// <summary>
 304                 ///   Returns the object associated with a given name in the declaration
 305                 ///   space.  This is the inverse operation of `DefineName'
 306                 /// </summary>
 307                 public object GetDefinition (string name)
 308                 {
 309                         return defined_names [name];
 310                 }
 311
 312                 bool in_transit = false;
 313
 314                 /// <summary>
 315                 ///   This function is used to catch recursive definitions
 316                 ///   in declarations.
 317                 /// </summary>
 318                 public bool InTransit {
 319                         get {
 320                                 return in_transit;
 321                         }
 322
 323                         set {
 324                                 in_transit = value;
 325                         }
 326                 }
 327
 328                 public TypeContainer Parent {
 329                         get {
 330                                 return parent;
 331                         }
 332                 }
 333
 334                 /// <summary>
 335                 ///   Looks up the alias for the name
 336                 /// </summary>
 337                 public string LookupAlias (string name)
 338                 {
 339                         return RootContext.SourceBeingCompiled.LookupAlias (name);
 340                 }
 341
 342                 //
 343                 // root_types contains all the types.  All TopLevel types
 344                 // hence have a parent that points to `root_types', that is
 345                 // why there is a non-obvious test down here.
 346                 //
 347                 public bool IsTopLevel {
 348                         get {
 349                                 if (parent != null){
 350                                         if (parent.parent == null)
 351                                                 return true;
 352                                 }
 353                                 return false;
 354                         }
 355                 }
 356
 357                 public virtual void CloseType ()
 358                 {
 359                         if (!Created){
 360                                 try {
 361                                         TypeBuilder.CreateType ();
 362                                 } catch {
 363                                         //
 364                                         // The try/catch is needed because
 365                                         // nested enumerations fail to load when they
 366                                         // are defined.
 367                                         //
 368                                         // Even if this is the right order (enumerations
 369                                         // declared after types).
 370                                         //
 371                                         // Note that this still creates the type and
 372                                         // it is possible to save it
 373                                 }
 374                                 Created = true;
 375                         }
 376                 }
 377
 378                 /// <remarks>
 379                 ///  Should be overriten by the appropriate declaration space
 380                 /// <remarks>
 381                 public abstract TypeBuilder DefineType ();
 382
 383                 /// <summary>
 384                 ///   Define all members, but don't apply any attributes or do anything which may
 385                 ///   access not-yet-defined classes.  This method also creates the MemberCache.
 386                 /// </summary>
 387                 public abstract bool DefineMembers (TypeContainer parent);
 388
 389                 //
 390                 // Whether this is an `unsafe context'
 391                 //
 392                 public bool UnsafeContext {
 393                         get {
 394                                 if ((ModFlags & Modifiers.UNSAFE) != 0)
 395                                         return true;
 396                                 if (parent != null)
 397                                         return parent.UnsafeContext;
 398                                 return false;
 399                         }
 400                 }
 401
 402                 public static string MakeFQN (string nsn, string name)
 403                 {
 404                         string prefix = (nsn == "" ? "" : nsn + ".");
 405
 406                         return prefix + name;
 407                 }
 408
 409                 EmitContext type_resolve_ec;
 410                 EmitContext GetTypeResolveEmitContext (TypeContainer parent, Location loc)
 411                 {
 412                         type_resolve_ec = new EmitContext (parent, this, loc, null, null, ModFlags, false);
 413                         type_resolve_ec.ResolvingTypeTree = true;
 414
 415                         return type_resolve_ec;
 416                 }
 417
 418                 // <summary>
 419                 //    Looks up the type, as parsed into the expression `e'
 420                 // </summary>
 421                 public Type ResolveType (Expression e, bool silent, Location loc)
 422                 {
 423                         if (type_resolve_ec == null)
 424                                 type_resolve_ec = GetTypeResolveEmitContext (parent, loc);
 425                         type_resolve_ec.loc = loc;
 426
 427                         int errors = Report.Errors;
 428                         Expression d = e.Resolve (type_resolve_ec, ResolveFlags.Type);
 429                         if (d == null || d.eclass != ExprClass.Type){
 430                                 if (!silent && errors == Report.Errors){
 431                                         Report.Error (30002, loc, "Cannot find type `"+ e.ToString () +"'");
 432                                 }
 433                                 return null;
 434                         }
 435
 436                         return d.Type;
 437                 }
 438
 439                 // <summary>
 440                 //    Resolves the expression `e' for a type, and will recursively define
 441                 //    types.
 442                 // </summary>
 443                 public Expression ResolveTypeExpr (Expression e, bool silent, Location loc)
 444                 {
 445                         if (type_resolve_ec == null)
 446                                 type_resolve_ec = GetTypeResolveEmitContext (parent, loc);
 447
 448                         Expression d = e.Resolve (type_resolve_ec, ResolveFlags.Type);
 449                         if (d == null || d.eclass != ExprClass.Type){
 450                                 if (!silent){
 451                                         Report.Error (30002, loc, "Cannot find type `"+ e +"'");
 452                                 }
 453                                 return null;
 454                         }
 455
 456                         return d;
 457                 }
 458
 459                 Type LookupInterfaceOrClass (string ns, string name, out bool error)
 460                 {
 461                         DeclSpace parent;
 462                         Type t;
 463
 464                         error = false;
 465                         name = MakeFQN (ns, name);
 466
 467                         t  = TypeManager.LookupType (name);
 468                         if (t != null)
 469                                 return t;
 470
 471                         parent = (DeclSpace) RootContext.Tree.Decls [name];
 472                         if (parent == null)
 473                                 return null;
 474
 475                         t = parent.DefineType ();
 476                         if (t == null){
 477                                 Report.Error (30256, Location, "Class definition is circular: `"+name+"'");
 478                                 error = true;
 479                                 return null;
 480                         }
 481                         return t;
 482                 }
 483
 484                 public static void Error_AmbiguousTypeReference (Location loc, string name, Type t1, Type t2)
 485                 {
 486                         Report.Error (104, loc,
 487                                       String.Format ("`{0}' is an ambiguous reference ({1} or {2}) ", name,
 488                                                      t1.FullName, t2.FullName));
 489                 }
 490
 491                 /// <summary>
 492                 ///   GetType is used to resolve type names at the DeclSpace level.
 493                 ///   Use this to lookup class/struct bases, interface bases or
 494                 ///   delegate type references
 495                 /// </summary>
 496                 ///
 497                 /// <remarks>
 498                 ///   Contrast this to LookupType which is used inside method bodies to
 499                 ///   lookup types that have already been defined.  GetType is used
 500                 ///   during the tree resolution process and potentially define
 501                 ///   recursively the type
 502                 /// </remarks>
 503                 public Type FindType (Location loc, string name)
 504                 {
 505                         Type t;
 506                         bool error;
 507
 508                         //
 509                         // For the case the type we are looking for is nested within this one
 510                         // or is in any base class
 511                         //
 512                         DeclSpace containing_ds = this;
 513
 514                         while (containing_ds != null){
 515                                 Type current_type = containing_ds.TypeBuilder;
 516
 517                                 while (current_type != null) {
 518                                         string pre = current_type.FullName;
 519
 520                                         t = LookupInterfaceOrClass (pre, name, out error);
 521                                         if (error)
 522                                                 return null;
 523
 524                                         if (t != null)
 525                                                 return t;
 526
 527                                         current_type = current_type.BaseType;
 528                                 }
 529                                 containing_ds = containing_ds.Parent;
 530                         }
 531
 532                         //
 533                         // Attempt to lookup the class on our namespace and all it's implicit parents
 534                         //
 535                         for (string ns = Namespace.Name; ns != null; ns = RootContext.ImplicitParent (ns)) {
 536
 537                                 t = LookupInterfaceOrClass (ns, name, out error);
 538                                 if (error)
 539                                         return null;
 540
 541                                 if (t != null)
 542                                         return t;
 543                         }
 544
 545                         //
 546                         // Attempt to do a direct unqualified lookup
 547                         //
 548                         t = LookupInterfaceOrClass ("", name, out error);
 549                         if (error)
 550                                 return null;
 551
 552                         if (t != null)
 553                                 return t;
 554
 555                         //
 556                         // Attempt to lookup the class on any of the `using'
 557                         // namespaces
 558                         //
 559
 560                         for (Namespace ns = Namespace; ns != null; ns = ns.Parent){
 561
 562                                 t = LookupInterfaceOrClass (ns.Name, name, out error);
 563                                 if (error)
 564                                         return null;
 565
 566                                 if (t != null)
 567                                         return t;
 568
 569                                 //
 570                                 // Now check the using clause list
 571                                 //
 572                                 ICollection imports_list = RootContext.SourceBeingCompiled.ImportsTable;
 573
 574                                 if (imports_list == null)
 575                                         continue;
 576
 577                                 Type match = null;
 578                                 foreach (SourceBeingCompiled.ImportsEntry ue in imports_list){
 579                                         match = LookupInterfaceOrClass (ue.Name, name, out error);
 580                                         if (error)
 581                                                 return null;
 582
 583                                         if (match != null){
 584                                                 if (t != null){
 585                                                         Error_AmbiguousTypeReference (loc, name, t, match);
 586                                                         return null;
 587                                                 }
 588
 589                                                 t = match;
 590                                                 ue.Used = true;
 591                                         }
 592                                 }
 593                                 if (t != null)
 594                                         return t;
 595                         }
 596
 597                         //Report.Error (246, Location, "Can not find type `"+name+"'");
 598                         return null;
 599                 }
 600
 601                 /// <remarks>
 602                 ///   This function is broken and not what you're looking for.  It should only
 603                 ///   be used while the type is still being created since it doesn't use the cache
 604                 ///   and relies on the filter doing the member name check.
 605                 /// </remarks>
 606                 public abstract MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 607                                                         MemberFilter filter, object criteria);
 608
 609                 /// <remarks>
 610                 ///   If we have a MemberCache, return it.  This property may return null if the
 611                 ///   class doesn't have a member cache or while it's still being created.
 612                 /// </remarks>
 613                 public abstract MemberCache MemberCache {
 614                         get;
 615                 }
 616         }
 617
 618         /// <summary>
 619         ///   This is a readonly list of MemberInfo's.
 620         /// </summary>
 621         public class MemberList : IList {
 622                 public readonly IList List;
 623                 int count;
 624
 625                 /// <summary>
 626                 ///   Create a new MemberList from the given IList.
 627                 /// </summary>
 628                 public MemberList (IList list)
 629                 {
 630                         if (list != null)
 631                                 this.List = list;
 632                         else
 633                                 this.List = new ArrayList ();
 634                         count = List.Count;
 635                 }
 636
 637                 /// <summary>
 638                 ///   Concatenate the ILists `first' and `second' to a new MemberList.
 639                 /// </summary>
 640                 public MemberList (IList first, IList second)
 641                 {
 642                         ArrayList list = new ArrayList ();
 643                         list.AddRange (first);
 644                         list.AddRange (second);
 645                         count = list.Count;
 646                         List = list;
 647                 }
 648
 649                 public static readonly MemberList Empty = new MemberList (new ArrayList ());
 650
 651                 /// <summary>
 652                 ///   Cast the MemberList into a MemberInfo[] array.
 653                 /// </summary>
 654                 /// <remarks>
 655                 ///   This is an expensive operation, only use it if it's really necessary.
 656                 /// </remarks>
 657                 public static explicit operator MemberInfo [] (MemberList list)
 658                 {
 659                         Timer.StartTimer (TimerType.MiscTimer);
 660                         MemberInfo [] result = new MemberInfo [list.Count];
 661                         list.CopyTo (result, 0);
 662                         Timer.StopTimer (TimerType.MiscTimer);
 663                         return result;
 664                 }
 665
 666                 // ICollection
 667
 668                 public int Count {
 669                         get {
 670                                 return count;
 671                         }
 672                 }
 673
 674                 public bool IsSynchronized {
 675                         get {
 676                                 return List.IsSynchronized;
 677                         }
 678                 }
 679
 680                 public object SyncRoot {
 681                         get {
 682                                 return List.SyncRoot;
 683                         }
 684                 }
 685
 686                 public void CopyTo (Array array, int index)
 687                 {
 688                         List.CopyTo (array, index);
 689                 }
 690
 691                 // IEnumerable
 692
 693                 public IEnumerator GetEnumerator ()
 694                 {
 695                         return List.GetEnumerator ();
 696                 }
 697
 698                 // IList
 699
 700                 public bool IsFixedSize {
 701                         get {
 702                                 return true;
 703                         }
 704                 }
 705
 706                 public bool IsReadOnly {
 707                         get {
 708                                 return true;
 709                         }
 710                 }
 711
 712                 object IList.this [int index] {
 713                         get {
 714                                 return List [index];
 715                         }
 716
 717                         set {
 718                                 throw new NotSupportedException ();
 719                         }
 720                 }
 721
 722                 // FIXME: try to find out whether we can avoid the cast in this indexer.
 723                 public MemberInfo this [int index] {
 724                         get {
 725                                 return (MemberInfo) List [index];
 726                         }
 727                 }
 728
 729                 public int Add (object value)
 730                 {
 731                         throw new NotSupportedException ();
 732                 }
 733
 734                 public void Clear ()
 735                 {
 736                         throw new NotSupportedException ();
 737                 }
 738
 739                 public bool Contains (object value)
 740                 {
 741                         return List.Contains (value);
 742                 }
 743
 744                 public int IndexOf (object value)
 745                 {
 746                         return List.IndexOf (value);
 747                 }
 748
 749                 public void Insert (int index, object value)
 750                 {
 751                         throw new NotSupportedException ();
 752                 }
 753
 754                 public void Remove (object value)
 755                 {
 756                         throw new NotSupportedException ();
 757                 }
 758
 759                 public void RemoveAt (int index)
 760                 {
 761                         throw new NotSupportedException ();
 762                 }
 763         }
 764
 765         /// <summary>
 766         ///   This interface is used to get all members of a class when creating the
 767         ///   member cache.  It must be implemented by all DeclSpace derivatives which
 768         ///   want to support the member cache and by TypeHandle to get caching of
 769         ///   non-dynamic types.
 770         /// </summary>
 771         public interface IMemberContainer {
 772                 /// <summary>
 773                 ///   The name of the IMemberContainer.  This is only used for
 774                 ///   debugging purposes.
 775                 /// </summary>
 776                 string Name {
 777                         get;
 778                 }
 779
 780                 /// <summary>
 781                 ///   The type of this IMemberContainer.
 782                 /// </summary>
 783                 Type Type {
 784                         get;
 785                 }
 786
 787                 /// <summary>
 788                 ///   Returns the IMemberContainer of the parent class or null if this
 789                 ///   is an interface or TypeManger.object_type.
 790                 ///   This is used when creating the member cache for a class to get all
 791                 ///   members from the parent class.
 792                 /// </summary>
 793                 IMemberContainer Parent {
 794                         get;
 795                 }
 796
 797                 /// <summary>
 798                 ///   Whether this is an interface.
 799                 /// </summary>
 800                 bool IsInterface {
 801                         get;
 802                 }
 803
 804                 /// <summary>
 805                 ///   Returns all members of this class with the corresponding MemberTypes
 806                 ///   and BindingFlags.
 807                 /// </summary>
 808                 /// <remarks>
 809                 ///   When implementing this method, make sure not to return any inherited
 810                 ///   members and check the MemberTypes and BindingFlags properly.
 811                 ///   Unfortunately, System.Reflection is lame and doesn't provide a way to
 812                 ///   get the BindingFlags (static/non-static,public/non-public) in the
 813                 ///   MemberInfo class, but the cache needs this information.  That's why
 814                 ///   this method is called multiple times with different BindingFlags.
 815                 /// </remarks>
 816                 MemberList GetMembers (MemberTypes mt, BindingFlags bf);
 817
 818                 /// <summary>
 819                 ///   Return the container's member cache.
 820                 /// </summary>
 821                 MemberCache MemberCache {
 822                         get;
 823                 }
 824         }
 825
 826         /// <summary>
 827         ///   The MemberCache is used by dynamic and non-dynamic types to speed up
 828         ///   member lookups.  It has a member name based hash table; it maps each member
 829         ///   name to a list of CacheEntry objects.  Each CacheEntry contains a MemberInfo
 830         ///   and the BindingFlags that were initially used to get it.  The cache contains
 831         ///   all members of the current class and all inherited members.  If this cache is
 832         ///   for an interface types, it also contains all inherited members.
 833         ///
 834         ///   There are two ways to get a MemberCache:
 835         ///   * if this is a dynamic type, lookup the corresponding DeclSpace and then
 836         ///     use the DeclSpace.MemberCache property.
 837         ///   * if this not a dynamic type, call TypeHandle.GetTypeHandle() to get a
 838         ///     TypeHandle instance for the type and then use TypeHandle.MemberCache.
 839         /// </summary>
 840         public class MemberCache {
 841                 public readonly IMemberContainer Container;
 842                 protected CaseInsensitiveHashtable member_hash;
 843                 protected CaseInsensitiveHashtable method_hash;
 844                 protected CaseInsensitiveHashtable interface_hash;
 845
 846                 /// <summary>
 847                 ///   Create a new MemberCache for the given IMemberContainer `container'.
 848                 /// </summary>
 849                 public MemberCache (IMemberContainer container)
 850                 {
 851                         this.Container = container;
 852
 853                         Timer.IncrementCounter (CounterType.MemberCache);
 854                         Timer.StartTimer (TimerType.CacheInit);
 855
 856                         interface_hash = new CaseInsensitiveHashtable ();
 857
 858                         // If we have a parent class (we have a parent class unless we're
 859                         // TypeManager.object_type), we deep-copy its MemberCache here.
 860                         if (Container.Parent != null)
 861                                 member_hash = SetupCache (Container.Parent.MemberCache);
 862                         else if (Container.IsInterface)
 863                                 member_hash = SetupCacheForInterface ();
 864                         else
 865                                 member_hash = new CaseInsensitiveHashtable ();
 866
 867                         // If this is neither a dynamic type nor an interface, create a special
 868                         // method cache with all declared and inherited methods.
 869                         Type type = container.Type;
 870                         if (!(type is TypeBuilder) && !type.IsInterface) {
 871                                 method_hash = new CaseInsensitiveHashtable ();
 872                                 AddMethods (type);
 873                         }
 874
 875                         // Add all members from the current class.
 876                         AddMembers (Container);
 877
 878                         Timer.StopTimer (TimerType.CacheInit);
 879                 }
 880
 881                 /// <summary>
 882                 ///   Bootstrap this member cache by doing a deep-copy of our parent.
 883                 /// </summary>
 884                 CaseInsensitiveHashtable SetupCache (MemberCache parent)
 885                 {
 886                         CaseInsensitiveHashtable hash = new CaseInsensitiveHashtable ();
 887
 888                         IDictionaryEnumerator it = parent.member_hash.GetEnumerator ();
 889                         while (it.MoveNext ()) {
 890                                 ArrayList al = (ArrayList) it.Value;
 891                                 // Constructors are never inherited and all have the same key
 892                                 if ((((CacheEntry)al [0]).EntryType & EntryType.Constructor) == 0)
 893                                         hash [it.Key] = ((ArrayList) it.Value).Clone ();
 894                         }
 895
 896                         return hash;
 897                 }
 898
 899                 void AddInterfaces (MemberCache parent)
 900                 {
 901                         foreach (Type iface in parent.interface_hash.Keys) {
 902                                 if (!interface_hash.Contains (iface))
 903                                         interface_hash.Add (iface, true);
 904                         }
 905                 }
 906
 907                 /// <summary>
 908                 ///   Add the contents of `new_hash' to `hash'.
 909                 /// </summary>
 910                 void AddHashtable (Hashtable hash, Hashtable new_hash)
 911                 {
 912                         IDictionaryEnumerator it = new_hash.GetEnumerator ();
 913                         while (it.MoveNext ()) {
 914                                 ArrayList list = (ArrayList) hash [it.Key];
 915                                 if (list != null)
 916                                         list.AddRange ((ArrayList) it.Value);
 917                                 else
 918                                         hash [it.Key] = ((ArrayList) it.Value).Clone ();
 919                         }
 920                 }
 921
 922                 /// <summary>
 923                 ///   Bootstrap the member cache for an interface type.
 924                 ///   Type.GetMembers() won't return any inherited members for interface types,
 925                 ///   so we need to do this manually.  Interfaces also inherit from System.Object.
 926                 /// </summary>
 927                 CaseInsensitiveHashtable SetupCacheForInterface ()
 928                 {
 929                         CaseInsensitiveHashtable hash = SetupCache (TypeHandle.ObjectType.MemberCache);
 930                         Type [] ifaces = TypeManager.GetInterfaces (Container.Type);
 931
 932                         foreach (Type iface in ifaces) {
 933                                 if (interface_hash.Contains (iface))
 934                                         continue;
 935                                 interface_hash.Add (iface, true);
 936
 937                                 IMemberContainer iface_container =
 938                                         TypeManager.LookupMemberContainer (iface);
 939
 940                                 MemberCache iface_cache = iface_container.MemberCache;
 941                                 AddHashtable (hash, iface_cache.member_hash);
 942                                 AddInterfaces (iface_cache);
 943                         }
 944
 945                         return hash;
 946                 }
 947
 948                 /// <summary>
 949                 ///   Add all members from class `container' to the cache.
 950                 /// </summary>
 951                 void AddMembers (IMemberContainer container)
 952                 {
 953                         // We need to call AddMembers() with a single member type at a time
 954                         // to get the member type part of CacheEntry.EntryType right.
 955                         AddMembers (MemberTypes.Constructor, container);
 956                         AddMembers (MemberTypes.Field, container);
 957                         AddMembers (MemberTypes.Method, container);
 958                         AddMembers (MemberTypes.Property, container);
 959                         AddMembers (MemberTypes.Event, container);
 960                         // Nested types are returned by both Static and Instance searches.
 961                         AddMembers (MemberTypes.NestedType,
 962                                     BindingFlags.Static | BindingFlags.Public, container);
 963                         AddMembers (MemberTypes.NestedType,
 964                                     BindingFlags.Static | BindingFlags.NonPublic, container);
 965                 }
 966
 967                 void AddMembers (MemberTypes mt, IMemberContainer container)
 968                 {
 969                         AddMembers (mt, BindingFlags.Static | BindingFlags.Public, container);
 970                         AddMembers (mt, BindingFlags.Static | BindingFlags.NonPublic, container);
 971                         AddMembers (mt, BindingFlags.Instance | BindingFlags.Public, container);
 972                         AddMembers (mt, BindingFlags.Instance | BindingFlags.NonPublic, container);
 973                 }
 974
 975                 /// <summary>
 976                 ///   Add all members from class `container' with the requested MemberTypes and
 977                 ///   BindingFlags to the cache.  This method is called multiple times with different
 978                 ///   MemberTypes and BindingFlags.
 979                 /// </summary>
 980                 void AddMembers (MemberTypes mt, BindingFlags bf, IMemberContainer container)
 981                 {
 982                         MemberList members = container.GetMembers (mt, bf);
 983                         BindingFlags new_bf = (container == Container) ?
 984                                 bf | BindingFlags.DeclaredOnly : bf;
 985
 986                         foreach (MemberInfo member in members) {
 987                                 string name = member.Name;
 988
 989                                 // We use a name-based hash table of ArrayList's.
 990                                 ArrayList list = (ArrayList) member_hash [name];
 991                                 if (list == null) {
 992                                         list = new ArrayList ();
 993                                         member_hash.Add (name, list);
 994                                 }
 995
 996                                 // When this method is called for the current class, the list will
 997                                 // already contain all inherited members from our parent classes.
 998                                 // We cannot add new members in front of the list since this'd be an
 999                                 // expensive operation, that's why the list is sorted in reverse order
1000                                 // (ie. members from the current class are coming last).
1001                                 list.Add (new CacheEntry (container, member, mt, bf));
1002                         }
1003                 }
1004
1005                 /// <summary>
1006                 ///   Add all declared and inherited methods from class `type' to the method cache.
1007                 /// </summary>
1008                 void AddMethods (Type type)
1009                 {
1010                         AddMethods (BindingFlags.Static | BindingFlags.Public, type);
1011                         AddMethods (BindingFlags.Static | BindingFlags.NonPublic, type);
1012                         AddMethods (BindingFlags.Instance | BindingFlags.Public, type);
1013                         AddMethods (BindingFlags.Instance | BindingFlags.NonPublic, type);
1014                 }
1015
1016                 void AddMethods (BindingFlags bf, Type type)
1017                 {
1018                         MemberInfo [] members = type.GetMethods (bf);
1019
1020                         foreach (MethodBase member in members) {
1021                                 string name = member.Name;
1022
1023                                 // Varargs methods aren't allowed in C# code.
1024                                 if ((member.CallingConvention & CallingConventions.VarArgs) != 0)
1025                                         continue;
1026
1027                                 // We use a name-based hash table of ArrayList's.
1028                                 ArrayList list = (ArrayList) method_hash [name];
1029                                 if (list == null) {
1030                                         list = new ArrayList ();
1031                                         method_hash.Add (name, list);
1032                                 }
1033
1034                                 // Unfortunately, the elements returned by Type.GetMethods() aren't
1035                                 // sorted so we need to do this check for every member.
1036                                 BindingFlags new_bf = bf;
1037                                 if (member.DeclaringType == type)
1038                                         new_bf |= BindingFlags.DeclaredOnly;
1039
1040                                 list.Add (new CacheEntry (Container, member, MemberTypes.Method, new_bf));
1041                         }
1042                 }
1043
1044                 /// <summary>
1045                 ///   Compute and return a appropriate `EntryType' magic number for the given
1046                 ///   MemberTypes and BindingFlags.
1047                 /// </summary>
1048                 protected static EntryType GetEntryType (MemberTypes mt, BindingFlags bf)
1049                 {
1050                         EntryType type = EntryType.None;
1051
1052                         if ((mt & MemberTypes.Constructor) != 0)
1053                                 type |= EntryType.Constructor;
1054                         if ((mt & MemberTypes.Event) != 0)
1055                                 type |= EntryType.Event;
1056                         if ((mt & MemberTypes.Field) != 0)
1057                                 type |= EntryType.Field;
1058                         if ((mt & MemberTypes.Method) != 0)
1059                                 type |= EntryType.Method;
1060                         if ((mt & MemberTypes.Property) != 0)
1061                                 type |= EntryType.Property;
1062                         // Nested types are returned by static and instance searches.
1063                         if ((mt & MemberTypes.NestedType) != 0)
1064                                 type |= EntryType.NestedType | EntryType.Static | EntryType.Instance;
1065
1066                         if ((bf & BindingFlags.Instance) != 0)
1067                                 type |= EntryType.Instance;
1068                         if ((bf & BindingFlags.Static) != 0)
1069                                 type |= EntryType.Static;
1070                         if ((bf & BindingFlags.Public) != 0)
1071                                 type |= EntryType.Public;
1072                         if ((bf & BindingFlags.NonPublic) != 0)
1073                                 type |= EntryType.NonPublic;
1074                         if ((bf & BindingFlags.DeclaredOnly) != 0)
1075                                 type |= EntryType.Declared;
1076
1077                         return type;
1078                 }
1079
1080                 /// <summary>
1081                 ///   The `MemberTypes' enumeration type is a [Flags] type which means that it may
1082                 ///   denote multiple member types.  Returns true if the given flags value denotes a
1083                 ///   single member types.
1084                 /// </summary>
1085                 public static bool IsSingleMemberType (MemberTypes mt)
1086                 {
1087                         switch (mt) {
1088                         case MemberTypes.Constructor:
1089                         case MemberTypes.Event:
1090                         case MemberTypes.Field:
1091                         case MemberTypes.Method:
1092                         case MemberTypes.Property:
1093                         case MemberTypes.NestedType:
1094                                 return true;
1095
1096                         default:
1097                                 return false;
1098                         }
1099                 }
1100
1101                 /// <summary>
1102                 ///   We encode the MemberTypes and BindingFlags of each members in a "magic"
1103                 ///   number to speed up the searching process.
1104                 /// </summary>
1105                 [Flags]
1106                 protected enum EntryType {
1107                         None            = 0x000,
1108
1109                         Instance        = 0x001,
1110                         Static          = 0x002,
1111                         MaskStatic      = Instance|Static,
1112
1113                         Public          = 0x004,
1114                         NonPublic       = 0x008,
1115                         MaskProtection  = Public|NonPublic,
1116
1117                         Declared        = 0x010,
1118
1119                         Constructor     = 0x020,
1120                         Event           = 0x040,
1121                         Field           = 0x080,
1122                         Method          = 0x100,
1123                         Property        = 0x200,
1124                         NestedType      = 0x400,
1125
1126                         MaskType        = Constructor|Event|Field|Method|Property|NestedType
1127                 }
1128
1129                 protected struct CacheEntry {
1130                         public readonly IMemberContainer Container;
1131                         public readonly EntryType EntryType;
1132                         public readonly MemberInfo Member;
1133
1134                         public CacheEntry (IMemberContainer container, MemberInfo member,
1135                                            MemberTypes mt, BindingFlags bf)
1136                         {
1137                                 this.Container = container;
1138                                 this.Member = member;
1139                                 this.EntryType = GetEntryType (mt, bf);
1140                         }
1141                 }
1142
1143                 /// <summary>
1144                 ///   This is called each time we're walking up one level in the class hierarchy
1145                 ///   and checks whether we can abort the search since we've already found what
1146                 ///   we were looking for.
1147                 /// </summary>
1148                 protected bool DoneSearching (ArrayList list)
1149                 {
1150                         //
1151                         // We've found exactly one member in the current class and it's not
1152                         // a method or constructor.
1153                         //
1154                         if (list.Count == 1 && !(list [0] is MethodBase))
1155                                 return true;
1156
1157                         //
1158                         // Multiple properties: we query those just to find out the indexer
1159                         // name
1160                         //
1161                         if ((list.Count > 0) && (list [0] is PropertyInfo))
1162                                 return true;
1163
1164                         return false;
1165                 }
1166
1167                 /// <summary>
1168                 ///   Looks up members with name `name'.  If you provide an optional
1169                 ///   filter function, it'll only be called with members matching the
1170                 ///   requested member name.
1171                 ///
1172                 ///   This method will try to use the cache to do the lookup if possible.
1173                 ///
1174                 ///   Unlike other FindMembers implementations, this method will always
1175                 ///   check all inherited members - even when called on an interface type.
1176                 ///
1177                 ///   If you know that you're only looking for methods, you should use
1178                 ///   MemberTypes.Method alone since this speeds up the lookup a bit.
1179                 ///   When doing a method-only search, it'll try to use a special method
1180                 ///   cache (unless it's a dynamic type or an interface) and the returned
1181                 ///   MemberInfo's will have the correct ReflectedType for inherited methods.
1182                 ///   The lookup process will automatically restart itself in method-only
1183                 ///   search mode if it discovers that it's about to return methods.
1184                 /// </summary>
1185                 public MemberList FindMembers (MemberTypes mt, BindingFlags bf, string name,
1186                                                MemberFilter filter, object criteria)
1187                 {
1188                         bool declared_only = (bf & BindingFlags.DeclaredOnly) != 0;
1189                         bool method_search = mt == MemberTypes.Method;
1190                         // If we have a method cache and we aren't already doing a method-only search,
1191                         // then we restart a method search if the first match is a method.
1192                         bool do_method_search = !method_search && (method_hash != null);
1193 bf |= BindingFlags.IgnoreCase;
1194                         ArrayList applicable;
1195
1196                         // If this is a method-only search, we try to use the method cache if
1197                         // possible; a lookup in the method cache will return a MemberInfo with
1198                         // the correct ReflectedType for inherited methods.
1199                         if (method_search && (method_hash != null))
1200                                 applicable = (ArrayList) method_hash [name];
1201                         else
1202                                 applicable = (ArrayList) member_hash [name];
1203
1204                         if (applicable == null)
1205                                 return MemberList.Empty;
1206
1207                         ArrayList list = new ArrayList ();
1208
1209                         Timer.StartTimer (TimerType.CachedLookup);
1210
1211                         EntryType type = GetEntryType (mt, bf);
1212
1213                         IMemberContainer current = Container;
1214
1215                         // `applicable' is a list of all members with the given member name `name'
1216                         // in the current class and all its parent classes.  The list is sorted in
1217                         // reverse order due to the way how the cache is initialy created (to speed
1218                         // things up, we're doing a deep-copy of our parent).
1219
1220                         for (int i = applicable.Count-1; i >= 0; i--) {
1221                                 CacheEntry entry = (CacheEntry) applicable [i];
1222
1223                                 // This happens each time we're walking one level up in the class
1224                                 // hierarchy.  If we're doing a DeclaredOnly search, we must abort
1225                                 // the first time this happens (this may already happen in the first
1226                                 // iteration of this loop if there are no members with the name we're
1227                                 // looking for in the current class).
1228                                 if (entry.Container != current) {
1229                                         if (declared_only || DoneSearching (list))
1230                                                 break;
1231
1232                                         current = entry.Container;
1233                                 }
1234
1235                                 // Is the member of the correct type ?
1236                                 if ((entry.EntryType & type & EntryType.MaskType) == 0)
1237                                         continue;
1238
1239                                 // Is the member static/non-static ?
1240                                 if ((entry.EntryType & type & EntryType.MaskStatic) == 0)
1241                                         continue;
1242
1243                                 // Apply the filter to it.
1244                                 if (filter (entry.Member, criteria)) {
1245                                         if ((entry.EntryType & EntryType.MaskType) != EntryType.Method)
1246                                                 do_method_search = false;
1247                                         list.Add (entry.Member);
1248                                 }
1249                         }
1250
1251                         Timer.StopTimer (TimerType.CachedLookup);
1252
1253                         // If we have a method cache and we aren't already doing a method-only
1254                         // search, we restart in method-only search mode if the first match is
1255                         // a method.  This ensures that we return a MemberInfo with the correct
1256                         // ReflectedType for inherited methods.
1257                         if (do_method_search && (list.Count > 0))
1258                                 return FindMembers (MemberTypes.Method, bf, name, filter, criteria);
1259
1260                         return new MemberList (list);
1261                 }
1262         }
1263 }