mcs/mcs/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                 public static int length;
 264                 public static int small;
 265
 266                 /// <summary>
 267                 ///   Introduce @name into this declaration space and
 268                 ///   associates it with the object @o.  Note that for
 269                 ///   methods this will just point to the first method. o
 270                 /// </summary>
 271                 protected void DefineName (string name, object o)
 272                 {
 273                         defined_names.Add (name, o);
 274
 275 #if DEBUGME
 276                         int p = name.LastIndexOf (".");
 277                         int l = name.Length;
 278                         length += l;
 279                         small += l -p;
 280 #endif
 281                 }
 282
 283                 /// <summary>
 284                 ///   Returns the object associated with a given name in the declaration
 285                 ///   space.  This is the inverse operation of `DefineName'
 286                 /// </summary>
 287                 public object GetDefinition (string name)
 288                 {
 289                         return defined_names [name];
 290                 }
 291
 292                 bool in_transit = false;
 293
 294                 /// <summary>
 295                 ///   This function is used to catch recursive definitions
 296                 ///   in declarations.
 297                 /// </summary>
 298                 public bool InTransit {
 299                         get {
 300                                 return in_transit;
 301                         }
 302
 303                         set {
 304                                 in_transit = value;
 305                         }
 306                 }
 307
 308                 public TypeContainer Parent {
 309                         get {
 310                                 return parent;
 311                         }
 312                 }
 313
 314                 /// <summary>
 315                 ///   Looks up the alias for the name
 316                 /// </summary>
 317                 public string LookupAlias (string name)
 318                 {
 319                         if (Namespace != null)
 320                                 return Namespace.LookupAlias (name);
 321                         else
 322                                 return null;
 323                 }
 324
 325                 //
 326                 // root_types contains all the types.  All TopLevel types
 327                 // hence have a parent that points to `root_types', that is
 328                 // why there is a non-obvious test down here.
 329                 //
 330                 public bool IsTopLevel {
 331                         get {
 332                                 if (parent != null){
 333                                         if (parent.parent == null)
 334                                                 return true;
 335                                 }
 336                                 return false;
 337                         }
 338                 }
 339
 340                 public virtual void CloseType ()
 341                 {
 342                         if (!Created){
 343                                 try {
 344                                         TypeBuilder.CreateType ();
 345                                 } catch {
 346                                         //
 347                                         // The try/catch is needed because
 348                                         // nested enumerations fail to load when they
 349                                         // are defined.
 350                                         //
 351                                         // Even if this is the right order (enumerations
 352                                         // declared after types).
 353                                         //
 354                                         // Note that this still creates the type and
 355                                         // it is possible to save it
 356                                 }
 357                                 Created = true;
 358                         }
 359                 }
 360
 361                 /// <remarks>
 362                 ///  Should be overriten by the appropriate declaration space
 363                 /// <remarks>
 364                 public abstract TypeBuilder DefineType ();
 365
 366                 /// <summary>
 367                 ///   Define all members, but don't apply any attributes or do anything which may
 368                 ///   access not-yet-defined classes.  This method also creates the MemberCache.
 369                 /// </summary>
 370                 public abstract bool DefineMembers (TypeContainer parent);
 371
 372                 //
 373                 // Whether this is an `unsafe context'
 374                 //
 375                 public bool UnsafeContext {
 376                         get {
 377                                 if ((ModFlags & Modifiers.UNSAFE) != 0)
 378                                         return true;
 379                                 if (parent != null)
 380                                         return parent.UnsafeContext;
 381                                 return false;
 382                         }
 383                 }
 384
 385                 public static string MakeFQN (string nsn, string name)
 386                 {
 387                         if (nsn == "")
 388                                 return name;
 389                         return String.Concat (nsn, ".", name);
 390                 }
 391
 392                 EmitContext type_resolve_ec;
 393                 EmitContext GetTypeResolveEmitContext (TypeContainer parent, Location loc)
 394                 {
 395                         type_resolve_ec = new EmitContext (parent, this, loc, null, null, ModFlags, false);
 396                         type_resolve_ec.ResolvingTypeTree = true;
 397
 398                         return type_resolve_ec;
 399                 }
 400
 401                 // <summary>
 402                 //    Looks up the type, as parsed into the expression `e'
 403                 // </summary>
 404                 public Type ResolveType (Expression e, bool silent, Location loc)
 405                 {
 406                         if (type_resolve_ec == null)
 407                                 type_resolve_ec = GetTypeResolveEmitContext (parent, loc);
 408                         type_resolve_ec.loc = loc;
 409
 410                         int errors = Report.Errors;
 411                         Expression d = e.Resolve (type_resolve_ec, ResolveFlags.Type);
 412
 413                         if (d == null || d.eclass != ExprClass.Type){
 414                                 if (!silent && errors == Report.Errors){
 415                                         Report.Error (246, loc, "Cannot find type `"+ e.ToString () +"'");
 416                                 }
 417                                 return null;
 418                         }
 419
 420                         return d.Type;
 421                 }
 422
 423                 // <summary>
 424                 //    Resolves the expression `e' for a type, and will recursively define
 425                 //    types.
 426                 // </summary>
 427                 public Expression ResolveTypeExpr (Expression e, bool silent, Location loc)
 428                 {
 429                         if (type_resolve_ec == null)
 430                                 type_resolve_ec = GetTypeResolveEmitContext (parent, loc);
 431
 432                         Expression d = e.Resolve (type_resolve_ec, ResolveFlags.Type);
 433
 434                         if (d == null || d.eclass != ExprClass.Type){
 435                                 if (!silent){
 436                                         Report.Error (246, loc, "Cannot find type `"+ e +"'");
 437                                 }
 438                                 return null;
 439                         }
 440
 441                         return d;
 442                 }
 443
 444                 Type LookupInterfaceOrClass (string ns, string name, out bool error)
 445                 {
 446                         DeclSpace parent;
 447                         Type t;
 448
 449                         error = false;
 450                         name = MakeFQN (ns, name);
 451
 452                         t  = TypeManager.LookupType (name);
 453                         if (t != null)
 454                                 return t;
 455
 456                         parent = (DeclSpace) RootContext.Tree.Decls [name];
 457                         if (parent == null)
 458                                 return null;
 459
 460                         t = parent.DefineType ();
 461                         if (t == null){
 462                                 Report.Error (146, Location, "Class definition is circular: `"+name+"'");
 463                                 error = true;
 464                                 return null;
 465                         }
 466                         return t;
 467                 }
 468
 469                 public static void Error_AmbiguousTypeReference (Location loc, string name, Type t1, Type t2)
 470                 {
 471                         Report.Error (104, loc,
 472                                       String.Format ("`{0}' is an ambiguous reference ({1} or {2}) ", name,
 473                                                      t1.FullName, t2.FullName));
 474                 }
 475
 476                 /// <summary>
 477                 ///   GetType is used to resolve type names at the DeclSpace level.
 478                 ///   Use this to lookup class/struct bases, interface bases or
 479                 ///   delegate type references
 480                 /// </summary>
 481                 ///
 482                 /// <remarks>
 483                 ///   Contrast this to LookupType which is used inside method bodies to
 484                 ///   lookup types that have already been defined.  GetType is used
 485                 ///   during the tree resolution process and potentially define
 486                 ///   recursively the type
 487                 /// </remarks>
 488                 public Type FindType (Location loc, string name)
 489                 {
 490                         Type t;
 491                         bool error;
 492
 493                         //
 494                         // For the case the type we are looking for is nested within this one
 495                         // or is in any base class
 496                         //
 497                         DeclSpace containing_ds = this;
 498
 499                         while (containing_ds != null){
 500                                 Type current_type = containing_ds.TypeBuilder;
 501
 502                                 while (current_type != null) {
 503                                         string pre = current_type.FullName;
 504
 505                                         t = LookupInterfaceOrClass (pre, name, out error);
 506                                         if (error)
 507                                                 return null;
 508
 509                                         if (t != null)
 510                                                 return t;
 511
 512                                         current_type = current_type.BaseType;
 513                                 }
 514                                 containing_ds = containing_ds.Parent;
 515                         }
 516
 517                         //
 518                         // Attempt to lookup the class on our namespace and all it's implicit parents
 519                         //
 520                         for (string ns = Namespace.Name; ns != null; ns = RootContext.ImplicitParent (ns)) {
 521
 522                                 t = LookupInterfaceOrClass (ns, name, out error);
 523                                 if (error)
 524                                         return null;
 525
 526                                 if (t != null)
 527                                         return t;
 528                         }
 529
 530                         //
 531                         // Attempt to do a direct unqualified lookup
 532                         //
 533                         t = LookupInterfaceOrClass ("", name, out error);
 534                         if (error)
 535                                 return null;
 536
 537                         if (t != null)
 538                                 return t;
 539
 540                         //
 541                         // Attempt to lookup the class on any of the `using'
 542                         // namespaces
 543                         //
 544
 545                         for (Namespace ns = Namespace; ns != null; ns = ns.Parent){
 546
 547                                 t = LookupInterfaceOrClass (ns.Name, name, out error);
 548                                 if (error)
 549                                         return null;
 550
 551                                 if (t != null)
 552                                         return t;
 553
 554                                 //
 555                                 // Now check the using clause list
 556                                 //
 557                                 ArrayList using_list = ns.UsingTable;
 558
 559                                 if (using_list == null)
 560                                         continue;
 561
 562                                 Type match = null;
 563                                 foreach (Namespace.UsingEntry ue in using_list){
 564                                         match = LookupInterfaceOrClass (ue.Name, name, out error);
 565                                         if (error)
 566                                                 return null;
 567
 568                                         if (match != null){
 569                                                 if (t != null){
 570                                                         Error_AmbiguousTypeReference (loc, name, t, match);
 571                                                         return null;
 572                                                 }
 573
 574                                                 t = match;
 575                                                 ue.Used = true;
 576                                         }
 577                                 }
 578                                 if (t != null)
 579                                         return t;
 580                         }
 581
 582                         //Report.Error (246, Location, "Can not find type `"+name+"'");
 583                         return null;
 584                 }
 585
 586                 /// <remarks>
 587                 ///   This function is broken and not what you're looking for.  It should only
 588                 ///   be used while the type is still being created since it doesn't use the cache
 589                 ///   and relies on the filter doing the member name check.
 590                 /// </remarks>
 591                 public abstract MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 592                                                         MemberFilter filter, object criteria);
 593
 594                 /// <remarks>
 595                 ///   If we have a MemberCache, return it.  This property may return null if the
 596                 ///   class doesn't have a member cache or while it's still being created.
 597                 /// </remarks>
 598                 public abstract MemberCache MemberCache {
 599                         get;
 600                 }
 601         }
 602
 603         /// <summary>
 604         ///   This is a readonly list of MemberInfo's.
 605         /// </summary>
 606         public class MemberList : IList {
 607                 public readonly IList List;
 608                 int count;
 609
 610                 /// <summary>
 611                 ///   Create a new MemberList from the given IList.
 612                 /// </summary>
 613                 public MemberList (IList list)
 614                 {
 615                         if (list != null)
 616                                 this.List = list;
 617                         else
 618                                 this.List = new ArrayList ();
 619                         count = List.Count;
 620                 }
 621
 622                 /// <summary>
 623                 ///   Concatenate the ILists `first' and `second' to a new MemberList.
 624                 /// </summary>
 625                 public MemberList (IList first, IList second)
 626                 {
 627                         ArrayList list = new ArrayList ();
 628                         list.AddRange (first);
 629                         list.AddRange (second);
 630                         count = list.Count;
 631                         List = list;
 632                 }
 633
 634                 public static readonly MemberList Empty = new MemberList (new ArrayList ());
 635
 636                 /// <summary>
 637                 ///   Cast the MemberList into a MemberInfo[] array.
 638                 /// </summary>
 639                 /// <remarks>
 640                 ///   This is an expensive operation, only use it if it's really necessary.
 641                 /// </remarks>
 642                 public static explicit operator MemberInfo [] (MemberList list)
 643                 {
 644                         Timer.StartTimer (TimerType.MiscTimer);
 645                         MemberInfo [] result = new MemberInfo [list.Count];
 646                         list.CopyTo (result, 0);
 647                         Timer.StopTimer (TimerType.MiscTimer);
 648                         return result;
 649                 }
 650
 651                 // ICollection
 652
 653                 public int Count {
 654                         get {
 655                                 return count;
 656                         }
 657                 }
 658
 659                 public bool IsSynchronized {
 660                         get {
 661                                 return List.IsSynchronized;
 662                         }
 663                 }
 664
 665                 public object SyncRoot {
 666                         get {
 667                                 return List.SyncRoot;
 668                         }
 669                 }
 670
 671                 public void CopyTo (Array array, int index)
 672                 {
 673                         List.CopyTo (array, index);
 674                 }
 675
 676                 // IEnumerable
 677
 678                 public IEnumerator GetEnumerator ()
 679                 {
 680                         return List.GetEnumerator ();
 681                 }
 682
 683                 // IList
 684
 685                 public bool IsFixedSize {
 686                         get {
 687                                 return true;
 688                         }
 689                 }
 690
 691                 public bool IsReadOnly {
 692                         get {
 693                                 return true;
 694                         }
 695                 }
 696
 697                 object IList.this [int index] {
 698                         get {
 699                                 return List [index];
 700                         }
 701
 702                         set {
 703                                 throw new NotSupportedException ();
 704                         }
 705                 }
 706
 707                 // FIXME: try to find out whether we can avoid the cast in this indexer.
 708                 public MemberInfo this [int index] {
 709                         get {
 710                                 return (MemberInfo) List [index];
 711                         }
 712                 }
 713
 714                 public int Add (object value)
 715                 {
 716                         throw new NotSupportedException ();
 717                 }
 718
 719                 public void Clear ()
 720                 {
 721                         throw new NotSupportedException ();
 722                 }
 723
 724                 public bool Contains (object value)
 725                 {
 726                         return List.Contains (value);
 727                 }
 728
 729                 public int IndexOf (object value)
 730                 {
 731                         return List.IndexOf (value);
 732                 }
 733
 734                 public void Insert (int index, object value)
 735                 {
 736                         throw new NotSupportedException ();
 737                 }
 738
 739                 public void Remove (object value)
 740                 {
 741                         throw new NotSupportedException ();
 742                 }
 743
 744                 public void RemoveAt (int index)
 745                 {
 746                         throw new NotSupportedException ();
 747                 }
 748         }
 749
 750         /// <summary>
 751         ///   This interface is used to get all members of a class when creating the
 752         ///   member cache.  It must be implemented by all DeclSpace derivatives which
 753         ///   want to support the member cache and by TypeHandle to get caching of
 754         ///   non-dynamic types.
 755         /// </summary>
 756         public interface IMemberContainer {
 757                 /// <summary>
 758                 ///   The name of the IMemberContainer.  This is only used for
 759                 ///   debugging purposes.
 760                 /// </summary>
 761                 string Name {
 762                         get;
 763                 }
 764
 765                 /// <summary>
 766                 ///   The type of this IMemberContainer.
 767                 /// </summary>
 768                 Type Type {
 769                         get;
 770                 }
 771
 772                 /// <summary>
 773                 ///   Returns the IMemberContainer of the parent class or null if this
 774                 ///   is an interface or TypeManger.object_type.
 775                 ///   This is used when creating the member cache for a class to get all
 776                 ///   members from the parent class.
 777                 /// </summary>
 778                 IMemberContainer Parent {
 779                         get;
 780                 }
 781
 782                 /// <summary>
 783                 ///   Whether this is an interface.
 784                 /// </summary>
 785                 bool IsInterface {
 786                         get;
 787                 }
 788
 789                 /// <summary>
 790                 ///   Returns all members of this class with the corresponding MemberTypes
 791                 ///   and BindingFlags.
 792                 /// </summary>
 793                 /// <remarks>
 794                 ///   When implementing this method, make sure not to return any inherited
 795                 ///   members and check the MemberTypes and BindingFlags properly.
 796                 ///   Unfortunately, System.Reflection is lame and doesn't provide a way to
 797                 ///   get the BindingFlags (static/non-static,public/non-public) in the
 798                 ///   MemberInfo class, but the cache needs this information.  That's why
 799                 ///   this method is called multiple times with different BindingFlags.
 800                 /// </remarks>
 801                 MemberList GetMembers (MemberTypes mt, BindingFlags bf);
 802
 803                 /// <summary>
 804                 ///   Return the container's member cache.
 805                 /// </summary>
 806                 MemberCache MemberCache {
 807                         get;
 808                 }
 809         }
 810
 811         /// <summary>
 812         ///   The MemberCache is used by dynamic and non-dynamic types to speed up
 813         ///   member lookups.  It has a member name based hash table; it maps each member
 814         ///   name to a list of CacheEntry objects.  Each CacheEntry contains a MemberInfo
 815         ///   and the BindingFlags that were initially used to get it.  The cache contains
 816         ///   all members of the current class and all inherited members.  If this cache is
 817         ///   for an interface types, it also contains all inherited members.
 818         ///
 819         ///   There are two ways to get a MemberCache:
 820         ///   * if this is a dynamic type, lookup the corresponding DeclSpace and then
 821         ///     use the DeclSpace.MemberCache property.
 822         ///   * if this not a dynamic type, call TypeHandle.GetTypeHandle() to get a
 823         ///     TypeHandle instance for the type and then use TypeHandle.MemberCache.
 824         /// </summary>
 825         public class MemberCache {
 826                 public readonly IMemberContainer Container;
 827                 protected Hashtable member_hash;
 828                 protected Hashtable method_hash;
 829                 protected Hashtable interface_hash;
 830
 831                 /// <summary>
 832                 ///   Create a new MemberCache for the given IMemberContainer `container'.
 833                 /// </summary>
 834                 public MemberCache (IMemberContainer container)
 835                 {
 836                         this.Container = container;
 837
 838                         Timer.IncrementCounter (CounterType.MemberCache);
 839                         Timer.StartTimer (TimerType.CacheInit);
 840
 841                         interface_hash = new Hashtable ();
 842
 843                         // If we have a parent class (we have a parent class unless we're
 844                         // TypeManager.object_type), we deep-copy its MemberCache here.
 845                         if (Container.Parent != null)
 846                                 member_hash = SetupCache (Container.Parent.MemberCache);
 847                         else if (Container.IsInterface)
 848                                 member_hash = SetupCacheForInterface ();
 849                         else
 850                                 member_hash = new Hashtable ();
 851
 852                         // If this is neither a dynamic type nor an interface, create a special
 853                         // method cache with all declared and inherited methods.
 854                         Type type = container.Type;
 855                         if (!(type is TypeBuilder) && !type.IsInterface) {
 856                                 method_hash = new Hashtable ();
 857                                 AddMethods (type);
 858                         }
 859
 860                         // Add all members from the current class.
 861                         AddMembers (Container);
 862
 863                         Timer.StopTimer (TimerType.CacheInit);
 864                 }
 865
 866                 /// <summary>
 867                 ///   Bootstrap this member cache by doing a deep-copy of our parent.
 868                 /// </summary>
 869                 Hashtable SetupCache (MemberCache parent)
 870                 {
 871                         Hashtable hash = new Hashtable ();
 872
 873                         IDictionaryEnumerator it = parent.member_hash.GetEnumerator ();
 874                         while (it.MoveNext ()) {
 875                                 hash [it.Key] = ((ArrayList) it.Value).Clone ();
 876                         }
 877
 878                         return hash;
 879                 }
 880
 881                 void AddInterfaces (MemberCache parent)
 882                 {
 883                         foreach (Type iface in parent.interface_hash.Keys) {
 884                                 if (!interface_hash.Contains (iface))
 885                                         interface_hash.Add (iface, true);
 886                         }
 887                 }
 888
 889                 /// <summary>
 890                 ///   Add the contents of `new_hash' to `hash'.
 891                 /// </summary>
 892                 void AddHashtable (Hashtable hash, Hashtable new_hash)
 893                 {
 894                         IDictionaryEnumerator it = new_hash.GetEnumerator ();
 895                         while (it.MoveNext ()) {
 896                                 ArrayList list = (ArrayList) hash [it.Key];
 897                                 if (list != null)
 898                                         list.AddRange ((ArrayList) it.Value);
 899                                 else
 900                                         hash [it.Key] = ((ArrayList) it.Value).Clone ();
 901                         }
 902                 }
 903
 904                 /// <summary>
 905                 ///   Bootstrap the member cache for an interface type.
 906                 ///   Type.GetMembers() won't return any inherited members for interface types,
 907                 ///   so we need to do this manually.  Interfaces also inherit from System.Object.
 908                 /// </summary>
 909                 Hashtable SetupCacheForInterface ()
 910                 {
 911                         Hashtable hash = SetupCache (TypeHandle.ObjectType.MemberCache);
 912                         Type [] ifaces = TypeManager.GetInterfaces (Container.Type);
 913
 914                         foreach (Type iface in ifaces) {
 915                                 if (interface_hash.Contains (iface))
 916                                         continue;
 917                                 interface_hash.Add (iface, true);
 918
 919                                 IMemberContainer iface_container =
 920                                         TypeManager.LookupMemberContainer (iface);
 921
 922                                 MemberCache iface_cache = iface_container.MemberCache;
 923                                 AddHashtable (hash, iface_cache.member_hash);
 924                                 AddInterfaces (iface_cache);
 925                         }
 926
 927                         return hash;
 928                 }
 929
 930                 /// <summary>
 931                 ///   Add all members from class `container' to the cache.
 932                 /// </summary>
 933                 void AddMembers (IMemberContainer container)
 934                 {
 935                         // We need to call AddMembers() with a single member type at a time
 936                         // to get the member type part of CacheEntry.EntryType right.
 937                         AddMembers (MemberTypes.Constructor, container);
 938                         AddMembers (MemberTypes.Field, container);
 939                         AddMembers (MemberTypes.Method, container);
 940                         AddMembers (MemberTypes.Property, container);
 941                         AddMembers (MemberTypes.Event, container);
 942                         // Nested types are returned by both Static and Instance searches.
 943                         AddMembers (MemberTypes.NestedType,
 944                                     BindingFlags.Static | BindingFlags.Public, container);
 945                         AddMembers (MemberTypes.NestedType,
 946                                     BindingFlags.Static | BindingFlags.NonPublic, container);
 947                 }
 948
 949                 void AddMembers (MemberTypes mt, IMemberContainer container)
 950                 {
 951                         AddMembers (mt, BindingFlags.Static | BindingFlags.Public, container);
 952                         AddMembers (mt, BindingFlags.Static | BindingFlags.NonPublic, container);
 953                         AddMembers (mt, BindingFlags.Instance | BindingFlags.Public, container);
 954                         AddMembers (mt, BindingFlags.Instance | BindingFlags.NonPublic, container);
 955                 }
 956
 957                 /// <summary>
 958                 ///   Add all members from class `container' with the requested MemberTypes and
 959                 ///   BindingFlags to the cache.  This method is called multiple times with different
 960                 ///   MemberTypes and BindingFlags.
 961                 /// </summary>
 962                 void AddMembers (MemberTypes mt, BindingFlags bf, IMemberContainer container)
 963                 {
 964                         MemberList members = container.GetMembers (mt, bf);
 965                         BindingFlags new_bf = (container == Container) ?
 966                                 bf | BindingFlags.DeclaredOnly : bf;
 967
 968                         foreach (MemberInfo member in members) {
 969                                 string name = member.Name;
 970
 971                                 // We use a name-based hash table of ArrayList's.
 972                                 ArrayList list = (ArrayList) member_hash [name];
 973                                 if (list == null) {
 974                                         list = new ArrayList ();
 975                                         member_hash.Add (name, list);
 976                                 }
 977
 978                                 // When this method is called for the current class, the list will
 979                                 // already contain all inherited members from our parent classes.
 980                                 // We cannot add new members in front of the list since this'd be an
 981                                 // expensive operation, that's why the list is sorted in reverse order
 982                                 // (ie. members from the current class are coming last).
 983                                 list.Add (new CacheEntry (container, member, mt, bf));
 984                         }
 985                 }
 986
 987                 /// <summary>
 988                 ///   Add all declared and inherited methods from class `type' to the method cache.
 989                 /// </summary>
 990                 void AddMethods (Type type)
 991                 {
 992                         AddMethods (BindingFlags.Static | BindingFlags.Public |
 993                                     BindingFlags.FlattenHierarchy, type);
 994                         AddMethods (BindingFlags.Static | BindingFlags.NonPublic |
 995                                     BindingFlags.FlattenHierarchy, type);
 996                         AddMethods (BindingFlags.Instance | BindingFlags.Public, type);
 997                         AddMethods (BindingFlags.Instance | BindingFlags.NonPublic, type);
 998                 }
 999
1000                 void AddMethods (BindingFlags bf, Type type)
1001                 {
1002                         MemberInfo [] members = type.GetMethods (bf);
1003
1004                         foreach (MethodBase member in members) {
1005                                 string name = member.Name;
1006
1007                                 // Varargs methods aren't allowed in C# code.
1008                                 if ((member.CallingConvention & CallingConventions.VarArgs) != 0)
1009                                         continue;
1010
1011                                 // We use a name-based hash table of ArrayList's.
1012                                 ArrayList list = (ArrayList) method_hash [name];
1013                                 if (list == null) {
1014                                         list = new ArrayList ();
1015                                         method_hash.Add (name, list);
1016                                 }
1017
1018                                 // Unfortunately, the elements returned by Type.GetMethods() aren't
1019                                 // sorted so we need to do this check for every member.
1020                                 BindingFlags new_bf = bf;
1021                                 if (member.DeclaringType == type)
1022                                         new_bf |= BindingFlags.DeclaredOnly;
1023
1024                                 list.Add (new CacheEntry (Container, member, MemberTypes.Method, new_bf));
1025                         }
1026                 }
1027
1028                 /// <summary>
1029                 ///   Compute and return a appropriate `EntryType' magic number for the given
1030                 ///   MemberTypes and BindingFlags.
1031                 /// </summary>
1032                 protected static EntryType GetEntryType (MemberTypes mt, BindingFlags bf)
1033                 {
1034                         EntryType type = EntryType.None;
1035
1036                         if ((mt & MemberTypes.Constructor) != 0)
1037                                 type |= EntryType.Constructor;
1038                         if ((mt & MemberTypes.Event) != 0)
1039                                 type |= EntryType.Event;
1040                         if ((mt & MemberTypes.Field) != 0)
1041                                 type |= EntryType.Field;
1042                         if ((mt & MemberTypes.Method) != 0)
1043                                 type |= EntryType.Method;
1044                         if ((mt & MemberTypes.Property) != 0)
1045                                 type |= EntryType.Property;
1046                         // Nested types are returned by static and instance searches.
1047                         if ((mt & MemberTypes.NestedType) != 0)
1048                                 type |= EntryType.NestedType | EntryType.Static | EntryType.Instance;
1049
1050                         if ((bf & BindingFlags.Instance) != 0)
1051                                 type |= EntryType.Instance;
1052                         if ((bf & BindingFlags.Static) != 0)
1053                                 type |= EntryType.Static;
1054                         if ((bf & BindingFlags.Public) != 0)
1055                                 type |= EntryType.Public;
1056                         if ((bf & BindingFlags.NonPublic) != 0)
1057                                 type |= EntryType.NonPublic;
1058                         if ((bf & BindingFlags.DeclaredOnly) != 0)
1059                                 type |= EntryType.Declared;
1060
1061                         return type;
1062                 }
1063
1064                 /// <summary>
1065                 ///   The `MemberTypes' enumeration type is a [Flags] type which means that it may
1066                 ///   denote multiple member types.  Returns true if the given flags value denotes a
1067                 ///   single member types.
1068                 /// </summary>
1069                 public static bool IsSingleMemberType (MemberTypes mt)
1070                 {
1071                         switch (mt) {
1072                         case MemberTypes.Constructor:
1073                         case MemberTypes.Event:
1074                         case MemberTypes.Field:
1075                         case MemberTypes.Method:
1076                         case MemberTypes.Property:
1077                         case MemberTypes.NestedType:
1078                                 return true;
1079
1080                         default:
1081                                 return false;
1082                         }
1083                 }
1084
1085                 /// <summary>
1086                 ///   We encode the MemberTypes and BindingFlags of each members in a "magic"
1087                 ///   number to speed up the searching process.
1088                 /// </summary>
1089                 [Flags]
1090                 protected enum EntryType {
1091                         None            = 0x000,
1092
1093                         Instance        = 0x001,
1094                         Static          = 0x002,
1095                         MaskStatic      = Instance|Static,
1096
1097                         Public          = 0x004,
1098                         NonPublic       = 0x008,
1099                         MaskProtection  = Public|NonPublic,
1100
1101                         Declared        = 0x010,
1102
1103                         Constructor     = 0x020,
1104                         Event           = 0x040,
1105                         Field           = 0x080,
1106                         Method          = 0x100,
1107                         Property        = 0x200,
1108                         NestedType      = 0x400,
1109
1110                         MaskType        = Constructor|Event|Field|Method|Property|NestedType
1111                 }
1112
1113                 protected struct CacheEntry {
1114                         public readonly IMemberContainer Container;
1115                         public readonly EntryType EntryType;
1116                         public readonly MemberInfo Member;
1117
1118                         public CacheEntry (IMemberContainer container, MemberInfo member,
1119                                            MemberTypes mt, BindingFlags bf)
1120                         {
1121                                 this.Container = container;
1122                                 this.Member = member;
1123                                 this.EntryType = GetEntryType (mt, bf);
1124                         }
1125                 }
1126
1127                 /// <summary>
1128                 ///   This is called each time we're walking up one level in the class hierarchy
1129                 ///   and checks whether we can abort the search since we've already found what
1130                 ///   we were looking for.
1131                 /// </summary>
1132                 protected bool DoneSearching (ArrayList list)
1133                 {
1134                         //
1135                         // We've found exactly one member in the current class and it's not
1136                         // a method or constructor.
1137                         //
1138                         if (list.Count == 1 && !(list [0] is MethodBase))
1139                                 return true;
1140
1141                         //
1142                         // Multiple properties: we query those just to find out the indexer
1143                         // name
1144                         //
1145                         if ((list.Count > 0) && (list [0] is PropertyInfo))
1146                                 return true;
1147
1148                         return false;
1149                 }
1150
1151                 /// <summary>
1152                 ///   Looks up members with name `name'.  If you provide an optional
1153                 ///   filter function, it'll only be called with members matching the
1154                 ///   requested member name.
1155                 ///
1156                 ///   This method will try to use the cache to do the lookup if possible.
1157                 ///
1158                 ///   Unlike other FindMembers implementations, this method will always
1159                 ///   check all inherited members - even when called on an interface type.
1160                 ///
1161                 ///   If you know that you're only looking for methods, you should use
1162                 ///   MemberTypes.Method alone since this speeds up the lookup a bit.
1163                 ///   When doing a method-only search, it'll try to use a special method
1164                 ///   cache (unless it's a dynamic type or an interface) and the returned
1165                 ///   MemberInfo's will have the correct ReflectedType for inherited methods.
1166                 ///   The lookup process will automatically restart itself in method-only
1167                 ///   search mode if it discovers that it's about to return methods.
1168                 /// </summary>
1169                 public MemberList FindMembers (MemberTypes mt, BindingFlags bf, string name,
1170                                                MemberFilter filter, object criteria)
1171                 {
1172                         bool declared_only = (bf & BindingFlags.DeclaredOnly) != 0;
1173                         bool method_search = mt == MemberTypes.Method;
1174                         // If we have a method cache and we aren't already doing a method-only search,
1175                         // then we restart a method search if the first match is a method.
1176                         bool do_method_search = !method_search && (method_hash != null);
1177
1178                         ArrayList applicable;
1179
1180                         // If this is a method-only search, we try to use the method cache if
1181                         // possible; a lookup in the method cache will return a MemberInfo with
1182                         // the correct ReflectedType for inherited methods.
1183                         if (method_search && (method_hash != null))
1184                                 applicable = (ArrayList) method_hash [name];
1185                         else
1186                                 applicable = (ArrayList) member_hash [name];
1187
1188                         if (applicable == null)
1189                                 return MemberList.Empty;
1190
1191                         ArrayList list = new ArrayList ();
1192
1193                         Timer.StartTimer (TimerType.CachedLookup);
1194
1195                         EntryType type = GetEntryType (mt, bf);
1196
1197                         IMemberContainer current = Container;
1198
1199                         // `applicable' is a list of all members with the given member name `name'
1200                         // in the current class and all its parent classes.  The list is sorted in
1201                         // reverse order due to the way how the cache is initialy created (to speed
1202                         // things up, we're doing a deep-copy of our parent).
1203
1204                         for (int i = applicable.Count-1; i >= 0; i--) {
1205                                 CacheEntry entry = (CacheEntry) applicable [i];
1206
1207                                 // This happens each time we're walking one level up in the class
1208                                 // hierarchy.  If we're doing a DeclaredOnly search, we must abort
1209                                 // the first time this happens (this may already happen in the first
1210                                 // iteration of this loop if there are no members with the name we're
1211                                 // looking for in the current class).
1212                                 if (entry.Container != current) {
1213                                         if (declared_only || DoneSearching (list))
1214                                                 break;
1215
1216                                         current = entry.Container;
1217                                 }
1218
1219                                 // Is the member of the correct type ?
1220                                 if ((entry.EntryType & type & EntryType.MaskType) == 0)
1221                                         continue;
1222
1223                                 // Is the member static/non-static ?
1224                                 if ((entry.EntryType & type & EntryType.MaskStatic) == 0)
1225                                         continue;
1226
1227                                 // Apply the filter to it.
1228                                 if (filter (entry.Member, criteria)) {
1229                                         if ((entry.EntryType & EntryType.MaskType) != EntryType.Method)
1230                                                 do_method_search = false;
1231                                         list.Add (entry.Member);
1232                                 }
1233                         }
1234
1235                         Timer.StopTimer (TimerType.CachedLookup);
1236
1237                         // If we have a method cache and we aren't already doing a method-only
1238                         // search, we restart in method-only search mode if the first match is
1239                         // a method.  This ensures that we return a MemberInfo with the correct
1240                         // ReflectedType for inherited methods.
1241                         if (do_method_search && (list.Count > 0))
1242                                 return FindMembers (MemberTypes.Method, bf, name, filter, criteria);
1243
1244                         return new MemberList (list);
1245                 }
1246         }
1247 }