mcs/mbas/decl.cs

   1 //
   2 // decl.cs: Declaration base class for structs, classes, enums and interfaces.
   3 //
   4 // Author: Miguel de Icaza (miguel@gnu.org)
   5 //
   6 // Licensed under the terms of the GNU GPL
   7 //
   8 // (C) 2001 Ximian, Inc (http://www.ximian.com)
   9 //
  10 // TODO: Move the method verification stuff from the class.cs and interface.cs here
  11 //
  12
  13 using System;
  14 using System.Collections;
  15 using System.Reflection.Emit;
  16 using System.Reflection;
  17
  18 namespace Mono.MonoBASIC {
  19
  20         /// <summary>
  21         ///   Base representation for members.  This is only used to keep track
  22         ///   of Name, Location and Modifier flags.
  23         /// </summary>
  24         public abstract class MemberCore {
  25                 /// <summary>
  26                 ///   Public name
  27                 /// </summary>
  28                 public string Name;
  29
  30                 /// <summary>
  31                 ///   Modifier flags that the user specified in the source code
  32                 /// </summary>
  33                 public int ModFlags;
  34
  35                 /// <summary>
  36                 ///   Location where this declaration happens
  37                 /// </summary>
  38                 public readonly Location Location;
  39
  40                 public MemberCore (string name, Location loc)
  41                 {
  42                         Name = name;
  43                         Location = loc;
  44                 }
  45
  46                 protected void WarningNotHiding (TypeContainer parent)
  47                 {
  48                         /*Report.Warning (
  49                                 109, Location,
  50                                 "The member " + parent.MakeName (Name) + " does not hide an " +
  51                                 "inherited member.  The keyword new is not required");
  52                         */
  53                 }
  54
  55                 void Error_CannotChangeAccessModifiers (TypeContainer parent, MethodInfo parent_method,
  56                                                         string name)
  57                 {
  58                         //
  59                         // FIXME: report the old/new permissions?
  60                         //
  61                         Report.Error (
  62                                 507, Location, parent.MakeName (Name) +
  63                                 ": can't change the access modifiers when overriding inherited " +
  64                                 "member `" + name + "'");
  65                 }
  66
  67                 //
  68                 // Performs various checks on the MethodInfo `mb' regarding the modifier flags
  69                 // that have been defined.
  70                 //
  71                 // `name' is the user visible name for reporting errors (this is used to
  72                 // provide the right name regarding method names and properties)
  73                 //
  74                 protected bool CheckMethodAgainstBase (TypeContainer parent, MethodAttributes my_attrs,
  75                                                        MethodInfo mb, string name)
  76                 {
  77                         bool ok = true;
  78
  79                         if ((ModFlags & Modifiers.OVERRIDE) != 0){
  80                                 // Now we check that the overriden method is not final
  81                                 if (mb.IsFinal) \r
  82                                 {
  83                                         Report.Error (30267, Location, parent.MakeName (Name) + " : cannot " +
  84                                                 "override inherited member `" + name +
  85                                                 "' because it is NotOverridable.");
  86                                         ok = false;
  87                                 }
  88                                 else if (!(mb.IsAbstract || mb.IsVirtual)){
  89                                         Report.Error (
  90                                                 31086, Location, parent.MakeName (Name) +
  91                                                 ": Cannot override inherited member `" +
  92                                                 name + "' because it is not " +
  93                                                 "declared as Overridable");
  94                                         ok = false;
  95                                 }
  96
  97                                 //
  98                                 // Check that the permissions are not being changed
  99                                 //
 100                                 MethodAttributes thisp = my_attrs & MethodAttributes.MemberAccessMask;
 101                                 MethodAttributes parentp = mb.Attributes & MethodAttributes.MemberAccessMask;
 102
 103                                 if (thisp != parentp){
 104                                         Error_CannotChangeAccessModifiers (parent, mb, name);
 105                                         ok = false;
 106                                 }
 107                         }
 108
 109                         if ((ModFlags & ( Modifiers.NEW | Modifiers.SHADOWS | Modifiers.OVERRIDE )) == 0) {
 110                                 if ((ModFlags & Modifiers.NONVIRTUAL) != 0)     {
 111                                         Report.Error (31088, Location,
 112                                                 parent.MakeName (Name) + " cannot " +
 113                                                 "be declared NotOverridable since this method is " +
 114                                                 "not marked as Overrides");
 115                                 }
 116                         }
 117
 118                         if (mb.IsAbstract) {
 119                                 if ((ModFlags & (Modifiers.OVERRIDE)) == 0)     {
 120                                         if (Name != "Finalize") {
 121                                                 Report.Error (
 122                                                         31404, Location,
 123                                                         name + " cannot Shadows the method " +
 124                                                         parent.MakeName (Name) + " since it is declared " +
 125                                                         "'MustOverride' in base class");
 126                                         }
 127                                 }
 128                         }
 129                         else if (mb.IsVirtual){
 130                                 if ((ModFlags & (Modifiers.NEW | Modifiers.OVERRIDE | Modifiers.SHADOWS)) == 0){
 131                                         if (Name != "Finalize"){
 132                                                 Report.Warning (
 133                                                         40005, 2, Location, parent.MakeName (Name) +
 134                                                         " shadows overridable member `" + name +
 135                                                         "'.  To make the current member override that " +
 136                                                         "implementation, add the overrides keyword." );
 137                                                 ModFlags |= Modifiers.SHADOWS;
 138                                         }
 139                                 }
 140                         }
 141                         else {
 142                                 if ((ModFlags & (Modifiers.NEW | Modifiers.OVERRIDE |
 143                                         Modifiers.SHADOWS)) == 0){
 144                                         if (Name != "Finalize"){
 145                                                 Report.Warning (
 146                                                         40004, 1, Location, "The keyword Shadows is required on " +
 147                                                         parent.MakeName (Name) + " because it hides " +
 148                                                         "inherited member `" + name + "'");
 149                                                 ModFlags |= Modifiers.SHADOWS;
 150                                         }
 151                                 }
 152                         }
 153
 154                         return ok;
 155                 }
 156
 157                 public abstract bool Define (TypeContainer parent);
 158
 159                 //
 160                 // Whehter is it ok to use an unsafe pointer in this type container
 161                 //
 162                 public bool UnsafeOK (DeclSpace parent)
 163                 {
 164                         //
 165                         // First check if this MemberCore modifier flags has unsafe set
 166                         //
 167                         if ((ModFlags & Modifiers.UNSAFE) != 0)
 168                                 return true;
 169
 170                         if (parent.UnsafeContext)
 171                                 return true;
 172
 173                         Expression.UnsafeError (Location);
 174                         return false;
 175                 }
 176         }
 177
 178         //
 179         // FIXME: This is temporary outside DeclSpace, because I have to fix a bug
 180         // in MCS that makes it fail the lookup for the enum
 181         //
 182
 183                 /// <summary>
 184                 ///   The result value from adding an declaration into
 185                 ///   a struct or a class
 186                 /// </summary>
 187                 public enum AdditionResult {
 188                         /// <summary>
 189                         /// The declaration has been successfully
 190                         /// added to the declation space.
 191                         /// </summary>
 192                         Success,
 193
 194                         /// <summary>
 195                         ///   The symbol has already been defined.
 196                         /// </summary>
 197                         NameExists,
 198
 199                         /// <summary>
 200                         ///   Returned if the declation being added to the
 201                         ///   name space clashes with its container name.
 202                         ///
 203                         ///   The only exceptions for this are constructors
 204                         ///   and static constructors
 205                         /// </summary>
 206                         EnclosingClash,
 207
 208                         /// <summary>
 209                         ///   Returned if a constructor was created (because syntactically
 210                         ///   it looked like a constructor) but was not (because the name
 211                         ///   of the method is not the same as the container class
 212                         /// </summary>
 213                         NotAConstructor,
 214
 215                         /// <summary>
 216                         ///   This is only used by static constructors to emit the
 217                         ///   error 111, but this error for other things really
 218                         ///   happens at another level for other functions.
 219                         /// </summary>
 220                         MethodExists
 221                 }
 222
 223         /// <summary>
 224         ///   Base class for structs, classes, enumerations and interfaces.
 225         /// </summary>
 226         /// <remarks>
 227         ///   They all create new declaration spaces.  This
 228         ///   provides the common foundation for managing those name
 229         ///   spaces.
 230         /// </remarks>
 231         public abstract class DeclSpace : MemberCore {
 232                 /// <summary>
 233                 ///   this points to the actual definition that is being
 234                 ///   created with System.Reflection.Emit
 235                 /// </summary>
 236                 public TypeBuilder TypeBuilder;
 237
 238                 /// <summary>
 239                 ///   This variable tracks whether we have Closed the type
 240                 /// </summary>
 241                 public bool Created = false;
 242
 243                 //
 244                 // This is the namespace in which this typecontainer
 245                 // was declared.  We use this to resolve names.
 246                 //
 247                 public Namespace Namespace;
 248
 249                 public Hashtable Cache = new Hashtable ();
 250
 251                 public string Basename;
 252
 253                 /// <summary>
 254                 ///   defined_names is used for toplevel objects
 255                 /// </summary>
 256                 protected Hashtable defined_names;
 257
 258                 TypeContainer parent;
 259
 260                 public DeclSpace (TypeContainer parent, string name, Location l)
 261                         : base (name, l)
 262                 {
 263                         Basename = name.Substring (1 + name.LastIndexOf ('.'));
 264                         defined_names = new Hashtable ();
 265                         this.parent = parent;
 266                 }
 267
 268                 /// <summary>
 269                 ///   Returns a status code based purely on the name
 270                 ///   of the member being added
 271                 /// </summary>
 272                 protected AdditionResult IsValid (string name)
 273                 {
 274                         if (name == Basename)
 275                                 return AdditionResult.EnclosingClash;
 276
 277                         if (defined_names.Contains (name))
 278                                 return AdditionResult.NameExists;
 279
 280                         return AdditionResult.Success;
 281                 }
 282
 283                 /// <summary>
 284                 ///   Introduce @name into this declaration space and
 285                 ///   associates it with the object @o.  Note that for
 286                 ///   methods this will just point to the first method. o
 287                 /// </summary>
 288                 protected void DefineName (string name, object o)
 289                 {
 290                         try {
 291                                 defined_names.Add (name, o);
 292                         }
 293                         catch (ArgumentException exp) {
 294                                 Report.Error (30260, /*Location,*/
 295                                         "More than one defination with same name '" + name +
 296                                         "' is found in the container '" + Name + "'");
 297                     }
 298
 299                 }
 300
 301                 /// <summary>
 302                 ///   Returns the object associated with a given name in the declaration
 303                 ///   space.  This is the inverse operation of `DefineName'
 304                 /// </summary>
 305                 public object GetDefinition (string name)
 306                 {
 307                         return defined_names [name];
 308                 }
 309
 310                 bool in_transit = false;
 311
 312                 /// <summary>
 313                 ///   This function is used to catch recursive definitions
 314                 ///   in declarations.
 315                 /// </summary>
 316                 public bool InTransit {
 317                         get {
 318                                 return in_transit;
 319                         }
 320
 321                         set {
 322                                 in_transit = value;
 323                         }
 324                 }
 325
 326                 public TypeContainer Parent {
 327                         get {
 328                                 return parent;
 329                         }
 330                 }
 331
 332                 /// <summary>
 333                 ///   Looks up the alias for the name
 334                 /// </summary>
 335                 public string LookupAlias (string name)
 336                 {
 337                         return RootContext.SourceBeingCompiled.LookupAlias (name);
 338                 }
 339
 340                 //
 341                 // root_types contains all the types.  All TopLevel types
 342                 // hence have a parent that points to `root_types', that is
 343                 // why there is a non-obvious test down here.
 344                 //
 345                 public bool IsTopLevel {
 346                         get {
 347                                 if (parent != null){
 348                                         if (parent.parent == null)
 349                                                 return true;
 350                                 }
 351                                 return false;
 352                         }
 353                 }
 354
 355                 public virtual void CloseType ()
 356                 {
 357                         if (!Created){
 358                                 try {
 359                                         TypeBuilder.CreateType ();
 360                                 } catch {
 361                                         //
 362                                         // The try/catch is needed because
 363                                         // nested enumerations fail to load when they
 364                                         // are defined.
 365                                         //
 366                                         // Even if this is the right order (enumerations
 367                                         // declared after types).
 368                                         //
 369                                         // Note that this still creates the type and
 370                                         // it is possible to save it
 371                                 }
 372                                 Created = true;
 373                         }
 374                 }
 375
 376                 /// <remarks>
 377                 ///  Should be overriten by the appropriate declaration space
 378                 /// <remarks>
 379                 public abstract TypeBuilder DefineType ();
 380
 381                 /// <summary>
 382                 ///   Define all members, but don't apply any attributes or do anything which may
 383                 ///   access not-yet-defined classes.  This method also creates the MemberCache.
 384                 /// </summary>
 385                 public abstract bool DefineMembers (TypeContainer parent);
 386
 387                 //
 388                 // Whether this is an `unsafe context'
 389                 //
 390                 public bool UnsafeContext {
 391                         get {
 392                                 if ((ModFlags & Modifiers.UNSAFE) != 0)
 393                                         return true;
 394                                 if (parent != null)
 395                                         return parent.UnsafeContext;
 396                                 return false;
 397                         }
 398                 }
 399
 400                 public static string MakeFQN (string nsn, string name)
 401                 {
 402                         string prefix = (nsn == "" ? "" : nsn + ".");
 403
 404                         return prefix + name;
 405                 }
 406
 407                 EmitContext type_resolve_ec;
 408                 EmitContext GetTypeResolveEmitContext (TypeContainer parent, Location loc)
 409                 {
 410                         type_resolve_ec = new EmitContext (parent, this, loc, null, null, ModFlags, false);
 411                         type_resolve_ec.ResolvingTypeTree = true;
 412
 413                         return type_resolve_ec;
 414                 }
 415
 416                 // <summary>
 417                 //    Looks up the type, as parsed into the expression `e'
 418                 // </summary>
 419                 public Type ResolveType (Expression e, bool silent, Location loc)
 420                 {
 421                         if (type_resolve_ec == null)
 422                                 type_resolve_ec = GetTypeResolveEmitContext (parent, loc);
 423                         type_resolve_ec.loc = loc;
 424
 425                         int errors = Report.Errors;
 426                         Expression d = e.Resolve (type_resolve_ec, ResolveFlags.Type);
 427                         if (d == null || d.eclass != ExprClass.Type){
 428                                 if (!silent && errors == Report.Errors){
 429                                         Report.Error (246, loc, "Cannot find type `"+ e.ToString () +"'");
 430                                 }
 431                                 return null;
 432                         }
 433
 434                         return d.Type;
 435                 }
 436
 437                 // <summary>
 438                 //    Resolves the expression `e' for a type, and will recursively define
 439                 //    types.
 440                 // </summary>
 441                 public Expression ResolveTypeExpr (Expression e, bool silent, Location loc)
 442                 {
 443                         if (type_resolve_ec == null)
 444                                 type_resolve_ec = GetTypeResolveEmitContext (parent, loc);
 445
 446                         Expression d = e.Resolve (type_resolve_ec, ResolveFlags.Type);
 447                         if (d == null || d.eclass != ExprClass.Type){
 448                                 if (!silent){
 449                                         Report.Error (246, loc, "Cannot find type `"+ e +"'");
 450                                 }
 451                                 return null;
 452                         }
 453
 454                         return d;
 455                 }
 456
 457                 Type LookupInterfaceOrClass (string ns, string name, out bool error)
 458                 {
 459                         DeclSpace parent;
 460                         Type t;
 461
 462                         error = false;
 463                         name = MakeFQN (ns, name);
 464
 465                         t  = TypeManager.LookupType (name);
 466                         if (t != null)
 467                                 return t;
 468
 469                         parent = (DeclSpace) RootContext.Tree.Decls [name];
 470                         if (parent == null)
 471                                 return null;
 472
 473                         t = parent.DefineType ();
 474                         if (t == null){
 475                                 Report.Error (30256, Location, "Class definition is circular: `"+name+"'");
 476                                 error = true;
 477                                 return null;
 478                         }
 479                         return t;
 480                 }
 481
 482                 public static void Error_AmbiguousTypeReference (Location loc, string name, Type t1, Type t2)
 483                 {
 484                         Report.Error (104, loc,
 485                                       String.Format ("`{0}' is an ambiguous reference ({1} or {2}) ", name,
 486                                                      t1.FullName, t2.FullName));
 487                 }
 488
 489                 /// <summary>
 490                 ///   GetType is used to resolve type names at the DeclSpace level.
 491                 ///   Use this to lookup class/struct bases, interface bases or
 492                 ///   delegate type references
 493                 /// </summary>
 494                 ///
 495                 /// <remarks>
 496                 ///   Contrast this to LookupType which is used inside method bodies to
 497                 ///   lookup types that have already been defined.  GetType is used
 498                 ///   during the tree resolution process and potentially define
 499                 ///   recursively the type
 500                 /// </remarks>
 501                 public Type FindType (Location loc, string name)
 502                 {
 503                         Type t;
 504                         bool error;
 505
 506                         //
 507                         // For the case the type we are looking for is nested within this one
 508                         // or is in any base class
 509                         //
 510                         DeclSpace containing_ds = this;
 511
 512                         while (containing_ds != null){
 513                                 Type current_type = containing_ds.TypeBuilder;
 514
 515                                 while (current_type != null) {
 516                                         string pre = current_type.FullName;
 517
 518                                         t = LookupInterfaceOrClass (pre, name, out error);
 519                                         if (error)
 520                                                 return null;
 521
 522                                         if (t != null)
 523                                                 return t;
 524
 525                                         current_type = current_type.BaseType;
 526                                 }
 527                                 containing_ds = containing_ds.Parent;
 528                         }
 529
 530                         //
 531                         // Attempt to lookup the class on our namespace and all it's implicit parents
 532                         //
 533                         for (string ns = Namespace.Name; ns != null; ns = RootContext.ImplicitParent (ns)) {
 534
 535                                 t = LookupInterfaceOrClass (ns, name, out error);
 536                                 if (error)
 537                                         return null;
 538
 539                                 if (t != null)
 540                                         return t;
 541                         }
 542
 543                         //
 544                         // Attempt to do a direct unqualified lookup
 545                         //
 546                         t = LookupInterfaceOrClass ("", name, out error);
 547                         if (error)
 548                                 return null;
 549
 550                         if (t != null)
 551                                 return t;
 552
 553                         //
 554                         // Attempt to lookup the class on any of the `using'
 555                         // namespaces
 556                         //
 557
 558                         for (Namespace ns = Namespace; ns != null; ns = ns.Parent){
 559
 560                                 t = LookupInterfaceOrClass (ns.Name, name, out error);
 561                                 if (error)
 562                                         return null;
 563
 564                                 if (t != null)
 565                                         return t;
 566
 567                                 //
 568                                 // Now check the using clause list
 569                                 //
 570                                 ICollection imports_list = RootContext.SourceBeingCompiled.ImportsTable;\r
 571 \r
 572                                 if (imports_list == null)\r
 573                                         continue;\r
 574
 575                                 Type match = null;
 576                                 foreach (SourceBeingCompiled.ImportsEntry ue in imports_list){
 577                                         match = LookupInterfaceOrClass (ue.Name, name, out error);
 578                                         if (error)
 579                                                 return null;
 580
 581                                         if (match != null){
 582                                                 if (t != null){
 583                                                         Error_AmbiguousTypeReference (loc, name, t, match);
 584                                                         return null;
 585                                                 }
 586
 587                                                 t = match;
 588                                                 ue.Used = true;
 589                                         }
 590                                 }
 591                                 if (t != null)
 592                                         return t;
 593                         }
 594
 595                         //Report.Error (246, Location, "Can not find type `"+name+"'");
 596                         return null;
 597                 }
 598
 599                 /// <remarks>
 600                 ///   This function is broken and not what you're looking for.  It should only
 601                 ///   be used while the type is still being created since it doesn't use the cache
 602                 ///   and relies on the filter doing the member name check.
 603                 /// </remarks>
 604                 public abstract MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 605                                                         MemberFilter filter, object criteria);
 606
 607                 /// <remarks>
 608                 ///   If we have a MemberCache, return it.  This property may return null if the
 609                 ///   class doesn't have a member cache or while it's still being created.
 610                 /// </remarks>
 611                 public abstract MemberCache MemberCache {
 612                         get;
 613                 }
 614         }
 615
 616         /// <summary>
 617         ///   This is a readonly list of MemberInfo's.
 618         /// </summary>
 619         public class MemberList : IList {
 620                 public readonly IList List;
 621                 int count;
 622
 623                 /// <summary>
 624                 ///   Create a new MemberList from the given IList.
 625                 /// </summary>
 626                 public MemberList (IList list)
 627                 {
 628                         if (list != null)
 629                                 this.List = list;
 630                         else
 631                                 this.List = new ArrayList ();
 632                         count = List.Count;
 633                 }
 634
 635                 /// <summary>
 636                 ///   Concatenate the ILists `first' and `second' to a new MemberList.
 637                 /// </summary>
 638                 public MemberList (IList first, IList second)
 639                 {
 640                         ArrayList list = new ArrayList ();
 641                         list.AddRange (first);
 642                         list.AddRange (second);
 643                         count = list.Count;
 644                         List = list;
 645                 }
 646
 647                 public static readonly MemberList Empty = new MemberList (new ArrayList ());
 648
 649                 /// <summary>
 650                 ///   Cast the MemberList into a MemberInfo[] array.
 651                 /// </summary>
 652                 /// <remarks>
 653                 ///   This is an expensive operation, only use it if it's really necessary.
 654                 /// </remarks>
 655                 public static explicit operator MemberInfo [] (MemberList list)
 656                 {
 657                         Timer.StartTimer (TimerType.MiscTimer);
 658                         MemberInfo [] result = new MemberInfo [list.Count];
 659                         list.CopyTo (result, 0);
 660                         Timer.StopTimer (TimerType.MiscTimer);
 661                         return result;
 662                 }
 663
 664                 // ICollection
 665
 666                 public int Count {
 667                         get {
 668                                 return count;
 669                         }
 670                 }
 671
 672                 public bool IsSynchronized {
 673                         get {
 674                                 return List.IsSynchronized;
 675                         }
 676                 }
 677
 678                 public object SyncRoot {
 679                         get {
 680                                 return List.SyncRoot;
 681                         }
 682                 }
 683
 684                 public void CopyTo (Array array, int index)
 685                 {
 686                         List.CopyTo (array, index);
 687                 }
 688
 689                 // IEnumerable
 690
 691                 public IEnumerator GetEnumerator ()
 692                 {
 693                         return List.GetEnumerator ();
 694                 }
 695
 696                 // IList
 697
 698                 public bool IsFixedSize {
 699                         get {
 700                                 return true;
 701                         }
 702                 }
 703
 704                 public bool IsReadOnly {
 705                         get {
 706                                 return true;
 707                         }
 708                 }
 709
 710                 object IList.this [int index] {
 711                         get {
 712                                 return List [index];
 713                         }
 714
 715                         set {
 716                                 throw new NotSupportedException ();
 717                         }
 718                 }
 719
 720                 // FIXME: try to find out whether we can avoid the cast in this indexer.
 721                 public MemberInfo this [int index] {
 722                         get {
 723                                 return (MemberInfo) List [index];
 724                         }
 725                 }
 726
 727                 public int Add (object value)
 728                 {
 729                         throw new NotSupportedException ();
 730                 }
 731
 732                 public void Clear ()
 733                 {
 734                         throw new NotSupportedException ();
 735                 }
 736
 737                 public bool Contains (object value)
 738                 {
 739                         return List.Contains (value);
 740                 }
 741
 742                 public int IndexOf (object value)
 743                 {
 744                         return List.IndexOf (value);
 745                 }
 746
 747                 public void Insert (int index, object value)
 748                 {
 749                         throw new NotSupportedException ();
 750                 }
 751
 752                 public void Remove (object value)
 753                 {
 754                         throw new NotSupportedException ();
 755                 }
 756
 757                 public void RemoveAt (int index)
 758                 {
 759                         throw new NotSupportedException ();
 760                 }
 761         }
 762
 763         /// <summary>
 764         ///   This interface is used to get all members of a class when creating the
 765         ///   member cache.  It must be implemented by all DeclSpace derivatives which
 766         ///   want to support the member cache and by TypeHandle to get caching of
 767         ///   non-dynamic types.
 768         /// </summary>
 769         public interface IMemberContainer {
 770                 /// <summary>
 771                 ///   The name of the IMemberContainer.  This is only used for
 772                 ///   debugging purposes.
 773                 /// </summary>
 774                 string Name {
 775                         get;
 776                 }
 777
 778                 /// <summary>
 779                 ///   The type of this IMemberContainer.
 780                 /// </summary>
 781                 Type Type {
 782                         get;
 783                 }
 784
 785                 /// <summary>
 786                 ///   Returns the IMemberContainer of the parent class or null if this
 787                 ///   is an interface or TypeManger.object_type.
 788                 ///   This is used when creating the member cache for a class to get all
 789                 ///   members from the parent class.
 790                 /// </summary>
 791                 IMemberContainer Parent {
 792                         get;
 793                 }
 794
 795                 /// <summary>
 796                 ///   Whether this is an interface.
 797                 /// </summary>
 798                 bool IsInterface {
 799                         get;
 800                 }
 801
 802                 /// <summary>
 803                 ///   Returns all members of this class with the corresponding MemberTypes
 804                 ///   and BindingFlags.
 805                 /// </summary>
 806                 /// <remarks>
 807                 ///   When implementing this method, make sure not to return any inherited
 808                 ///   members and check the MemberTypes and BindingFlags properly.
 809                 ///   Unfortunately, System.Reflection is lame and doesn't provide a way to
 810                 ///   get the BindingFlags (static/non-static,public/non-public) in the
 811                 ///   MemberInfo class, but the cache needs this information.  That's why
 812                 ///   this method is called multiple times with different BindingFlags.
 813                 /// </remarks>
 814                 MemberList GetMembers (MemberTypes mt, BindingFlags bf);
 815
 816                 /// <summary>
 817                 ///   Return the container's member cache.
 818                 /// </summary>
 819                 MemberCache MemberCache {
 820                         get;
 821                 }
 822         }
 823
 824         /// <summary>
 825         ///   The MemberCache is used by dynamic and non-dynamic types to speed up
 826         ///   member lookups.  It has a member name based hash table; it maps each member
 827         ///   name to a list of CacheEntry objects.  Each CacheEntry contains a MemberInfo
 828         ///   and the BindingFlags that were initially used to get it.  The cache contains
 829         ///   all members of the current class and all inherited members.  If this cache is
 830         ///   for an interface types, it also contains all inherited members.
 831         ///
 832         ///   There are two ways to get a MemberCache:
 833         ///   * if this is a dynamic type, lookup the corresponding DeclSpace and then
 834         ///     use the DeclSpace.MemberCache property.
 835         ///   * if this not a dynamic type, call TypeHandle.GetTypeHandle() to get a
 836         ///     TypeHandle instance for the type and then use TypeHandle.MemberCache.
 837         /// </summary>
 838         public class MemberCache {
 839                 public readonly IMemberContainer Container;
 840                 protected CaseInsensitiveHashtable member_hash;
 841                 protected CaseInsensitiveHashtable method_hash;
 842                 protected CaseInsensitiveHashtable interface_hash;
 843
 844                 /// <summary>
 845                 ///   Create a new MemberCache for the given IMemberContainer `container'.
 846                 /// </summary>
 847                 public MemberCache (IMemberContainer container)
 848                 {
 849                         this.Container = container;
 850
 851                         Timer.IncrementCounter (CounterType.MemberCache);
 852                         Timer.StartTimer (TimerType.CacheInit);
 853
 854                         interface_hash = new CaseInsensitiveHashtable ();
 855
 856                         // If we have a parent class (we have a parent class unless we're
 857                         // TypeManager.object_type), we deep-copy its MemberCache here.
 858                         if (Container.Parent != null)
 859                                 member_hash = SetupCache (Container.Parent.MemberCache);
 860                         else if (Container.IsInterface)
 861                                 member_hash = SetupCacheForInterface ();
 862                         else
 863                                 member_hash = new CaseInsensitiveHashtable ();
 864
 865                         // If this is neither a dynamic type nor an interface, create a special
 866                         // method cache with all declared and inherited methods.
 867                         Type type = container.Type;
 868                         if (!(type is TypeBuilder) && !type.IsInterface) {
 869                                 method_hash = new CaseInsensitiveHashtable ();
 870                                 AddMethods (type);
 871                         }
 872
 873                         // Add all members from the current class.
 874                         AddMembers (Container);
 875
 876                         Timer.StopTimer (TimerType.CacheInit);
 877                 }
 878
 879                 /// <summary>
 880                 ///   Bootstrap this member cache by doing a deep-copy of our parent.
 881                 /// </summary>
 882                 CaseInsensitiveHashtable SetupCache (MemberCache parent)
 883                 {
 884                         CaseInsensitiveHashtable hash = new CaseInsensitiveHashtable ();
 885
 886                         IDictionaryEnumerator it = parent.member_hash.GetEnumerator ();
 887                         while (it.MoveNext ()) {
 888                                 hash [it.Key] = ((ArrayList) it.Value).Clone ();
 889                         }
 890
 891                         return hash;
 892                 }
 893
 894                 void AddInterfaces (MemberCache parent)
 895                 {
 896                         foreach (Type iface in parent.interface_hash.Keys) {
 897                                 if (!interface_hash.Contains (iface))
 898                                         interface_hash.Add (iface, true);
 899                         }
 900                 }
 901
 902                 /// <summary>
 903                 ///   Add the contents of `new_hash' to `hash'.
 904                 /// </summary>
 905                 void AddHashtable (Hashtable hash, Hashtable new_hash)
 906                 {
 907                         IDictionaryEnumerator it = new_hash.GetEnumerator ();
 908                         while (it.MoveNext ()) {
 909                                 ArrayList list = (ArrayList) hash [it.Key];
 910                                 if (list != null)
 911                                         list.AddRange ((ArrayList) it.Value);
 912                                 else
 913                                         hash [it.Key] = ((ArrayList) it.Value).Clone ();
 914                         }
 915                 }
 916
 917                 /// <summary>
 918                 ///   Bootstrap the member cache for an interface type.
 919                 ///   Type.GetMembers() won't return any inherited members for interface types,
 920                 ///   so we need to do this manually.  Interfaces also inherit from System.Object.
 921                 /// </summary>
 922                 CaseInsensitiveHashtable SetupCacheForInterface ()
 923                 {
 924                         CaseInsensitiveHashtable hash = SetupCache (TypeHandle.ObjectType.MemberCache);
 925                         Type [] ifaces = TypeManager.GetInterfaces (Container.Type);
 926
 927                         foreach (Type iface in ifaces) {
 928                                 if (interface_hash.Contains (iface))
 929                                         continue;
 930                                 interface_hash.Add (iface, true);
 931
 932                                 IMemberContainer iface_container =
 933                                         TypeManager.LookupMemberContainer (iface);
 934
 935                                 MemberCache iface_cache = iface_container.MemberCache;
 936                                 AddHashtable (hash, iface_cache.member_hash);
 937                                 AddInterfaces (iface_cache);
 938                         }
 939
 940                         return hash;
 941                 }
 942
 943                 /// <summary>
 944                 ///   Add all members from class `container' to the cache.
 945                 /// </summary>
 946                 void AddMembers (IMemberContainer container)
 947                 {
 948                         // We need to call AddMembers() with a single member type at a time
 949                         // to get the member type part of CacheEntry.EntryType right.
 950                         AddMembers (MemberTypes.Constructor, container);
 951                         AddMembers (MemberTypes.Field, container);
 952                         AddMembers (MemberTypes.Method, container);
 953                         AddMembers (MemberTypes.Property, container);
 954                         AddMembers (MemberTypes.Event, container);
 955                         // Nested types are returned by both Static and Instance searches.
 956                         AddMembers (MemberTypes.NestedType,
 957                                     BindingFlags.Static | BindingFlags.Public, container);
 958                         AddMembers (MemberTypes.NestedType,
 959                                     BindingFlags.Static | BindingFlags.NonPublic, container);
 960                 }
 961
 962                 void AddMembers (MemberTypes mt, IMemberContainer container)
 963                 {
 964                         AddMembers (mt, BindingFlags.Static | BindingFlags.Public, container);
 965                         AddMembers (mt, BindingFlags.Static | BindingFlags.NonPublic, container);
 966                         AddMembers (mt, BindingFlags.Instance | BindingFlags.Public, container);
 967                         AddMembers (mt, BindingFlags.Instance | BindingFlags.NonPublic, container);
 968                 }
 969
 970                 /// <summary>
 971                 ///   Add all members from class `container' with the requested MemberTypes and
 972                 ///   BindingFlags to the cache.  This method is called multiple times with different
 973                 ///   MemberTypes and BindingFlags.
 974                 /// </summary>
 975                 void AddMembers (MemberTypes mt, BindingFlags bf, IMemberContainer container)
 976                 {
 977                         MemberList members = container.GetMembers (mt, bf);
 978                         BindingFlags new_bf = (container == Container) ?
 979                                 bf | BindingFlags.DeclaredOnly : bf;
 980
 981                         foreach (MemberInfo member in members) {
 982                                 string name = member.Name;
 983
 984                                 // We use a name-based hash table of ArrayList's.
 985                                 ArrayList list = (ArrayList) member_hash [name];
 986                                 if (list == null) {
 987                                         list = new ArrayList ();
 988                                         member_hash.Add (name, list);
 989                                 }
 990
 991                                 // When this method is called for the current class, the list will
 992                                 // already contain all inherited members from our parent classes.
 993                                 // We cannot add new members in front of the list since this'd be an
 994                                 // expensive operation, that's why the list is sorted in reverse order
 995                                 // (ie. members from the current class are coming last).
 996                                 list.Add (new CacheEntry (container, member, mt, bf));
 997                         }
 998                 }
 999
1000                 /// <summary>
1001                 ///   Add all declared and inherited methods from class `type' to the method cache.
1002                 /// </summary>
1003                 void AddMethods (Type type)
1004                 {
1005                         AddMethods (BindingFlags.Static | BindingFlags.Public, type);
1006                         AddMethods (BindingFlags.Static | BindingFlags.NonPublic, type);
1007                         AddMethods (BindingFlags.Instance | BindingFlags.Public, type);
1008                         AddMethods (BindingFlags.Instance | BindingFlags.NonPublic, type);
1009                 }
1010
1011                 void AddMethods (BindingFlags bf, Type type)
1012                 {
1013                         MemberInfo [] members = type.GetMethods (bf);
1014
1015                         foreach (MethodBase member in members) {
1016                                 string name = member.Name;
1017
1018                                 // Varargs methods aren't allowed in C# code.
1019                                 if ((member.CallingConvention & CallingConventions.VarArgs) != 0)
1020                                         continue;
1021
1022                                 // We use a name-based hash table of ArrayList's.
1023                                 ArrayList list = (ArrayList) method_hash [name];
1024                                 if (list == null) {
1025                                         list = new ArrayList ();
1026                                         method_hash.Add (name, list);
1027                                 }
1028
1029                                 // Unfortunately, the elements returned by Type.GetMethods() aren't
1030                                 // sorted so we need to do this check for every member.
1031                                 BindingFlags new_bf = bf;
1032                                 if (member.DeclaringType == type)
1033                                         new_bf |= BindingFlags.DeclaredOnly;
1034
1035                                 list.Add (new CacheEntry (Container, member, MemberTypes.Method, new_bf));
1036                         }
1037                 }
1038
1039                 /// <summary>
1040                 ///   Compute and return a appropriate `EntryType' magic number for the given
1041                 ///   MemberTypes and BindingFlags.
1042                 /// </summary>
1043                 protected static EntryType GetEntryType (MemberTypes mt, BindingFlags bf)
1044                 {
1045                         EntryType type = EntryType.None;
1046
1047                         if ((mt & MemberTypes.Constructor) != 0)
1048                                 type |= EntryType.Constructor;
1049                         if ((mt & MemberTypes.Event) != 0)
1050                                 type |= EntryType.Event;
1051                         if ((mt & MemberTypes.Field) != 0)
1052                                 type |= EntryType.Field;
1053                         if ((mt & MemberTypes.Method) != 0)
1054                                 type |= EntryType.Method;
1055                         if ((mt & MemberTypes.Property) != 0)
1056                                 type |= EntryType.Property;
1057                         // Nested types are returned by static and instance searches.
1058                         if ((mt & MemberTypes.NestedType) != 0)
1059                                 type |= EntryType.NestedType | EntryType.Static | EntryType.Instance;
1060
1061                         if ((bf & BindingFlags.Instance) != 0)
1062                                 type |= EntryType.Instance;
1063                         if ((bf & BindingFlags.Static) != 0)
1064                                 type |= EntryType.Static;
1065                         if ((bf & BindingFlags.Public) != 0)
1066                                 type |= EntryType.Public;
1067                         if ((bf & BindingFlags.NonPublic) != 0)
1068                                 type |= EntryType.NonPublic;
1069                         if ((bf & BindingFlags.DeclaredOnly) != 0)
1070                                 type |= EntryType.Declared;
1071
1072                         return type;
1073                 }
1074
1075                 /// <summary>
1076                 ///   The `MemberTypes' enumeration type is a [Flags] type which means that it may
1077                 ///   denote multiple member types.  Returns true if the given flags value denotes a
1078                 ///   single member types.
1079                 /// </summary>
1080                 public static bool IsSingleMemberType (MemberTypes mt)
1081                 {
1082                         switch (mt) {
1083                         case MemberTypes.Constructor:
1084                         case MemberTypes.Event:
1085                         case MemberTypes.Field:
1086                         case MemberTypes.Method:
1087                         case MemberTypes.Property:
1088                         case MemberTypes.NestedType:
1089                                 return true;
1090
1091                         default:
1092                                 return false;
1093                         }
1094                 }
1095
1096                 /// <summary>
1097                 ///   We encode the MemberTypes and BindingFlags of each members in a "magic"
1098                 ///   number to speed up the searching process.
1099                 /// </summary>
1100                 [Flags]
1101                 protected enum EntryType {
1102                         None            = 0x000,
1103
1104                         Instance        = 0x001,
1105                         Static          = 0x002,
1106                         MaskStatic      = Instance|Static,
1107
1108                         Public          = 0x004,
1109                         NonPublic       = 0x008,
1110                         MaskProtection  = Public|NonPublic,
1111
1112                         Declared        = 0x010,
1113
1114                         Constructor     = 0x020,
1115                         Event           = 0x040,
1116                         Field           = 0x080,
1117                         Method          = 0x100,
1118                         Property        = 0x200,
1119                         NestedType      = 0x400,
1120
1121                         MaskType        = Constructor|Event|Field|Method|Property|NestedType
1122                 }
1123
1124                 protected struct CacheEntry {
1125                         public readonly IMemberContainer Container;
1126                         public readonly EntryType EntryType;
1127                         public readonly MemberInfo Member;
1128
1129                         public CacheEntry (IMemberContainer container, MemberInfo member,
1130                                            MemberTypes mt, BindingFlags bf)
1131                         {
1132                                 this.Container = container;
1133                                 this.Member = member;
1134                                 this.EntryType = GetEntryType (mt, bf);
1135                         }
1136                 }
1137
1138                 /// <summary>
1139                 ///   This is called each time we're walking up one level in the class hierarchy
1140                 ///   and checks whether we can abort the search since we've already found what
1141                 ///   we were looking for.
1142                 /// </summary>
1143                 protected bool DoneSearching (ArrayList list)
1144                 {
1145                         //
1146                         // We've found exactly one member in the current class and it's not
1147                         // a method or constructor.
1148                         //
1149                         if (list.Count == 1 && !(list [0] is MethodBase))
1150                                 return true;
1151
1152                         //
1153                         // Multiple properties: we query those just to find out the indexer
1154                         // name
1155                         //
1156                         if ((list.Count > 0) && (list [0] is PropertyInfo))
1157                                 return true;
1158
1159                         return false;
1160                 }
1161
1162                 /// <summary>
1163                 ///   Looks up members with name `name'.  If you provide an optional
1164                 ///   filter function, it'll only be called with members matching the
1165                 ///   requested member name.
1166                 ///
1167                 ///   This method will try to use the cache to do the lookup if possible.
1168                 ///
1169                 ///   Unlike other FindMembers implementations, this method will always
1170                 ///   check all inherited members - even when called on an interface type.
1171                 ///
1172                 ///   If you know that you're only looking for methods, you should use
1173                 ///   MemberTypes.Method alone since this speeds up the lookup a bit.
1174                 ///   When doing a method-only search, it'll try to use a special method
1175                 ///   cache (unless it's a dynamic type or an interface) and the returned
1176                 ///   MemberInfo's will have the correct ReflectedType for inherited methods.
1177                 ///   The lookup process will automatically restart itself in method-only
1178                 ///   search mode if it discovers that it's about to return methods.
1179                 /// </summary>
1180                 public MemberList FindMembers (MemberTypes mt, BindingFlags bf, string name,
1181                                                MemberFilter filter, object criteria)
1182                 {
1183                         bool declared_only = (bf & BindingFlags.DeclaredOnly) != 0;
1184                         bool method_search = mt == MemberTypes.Method;
1185                         // If we have a method cache and we aren't already doing a method-only search,
1186                         // then we restart a method search if the first match is a method.
1187                         bool do_method_search = !method_search && (method_hash != null);
1188 bf |= BindingFlags.IgnoreCase;
1189                         ArrayList applicable;
1190
1191                         // If this is a method-only search, we try to use the method cache if
1192                         // possible; a lookup in the method cache will return a MemberInfo with
1193                         // the correct ReflectedType for inherited methods.
1194                         if (method_search && (method_hash != null))
1195                                 applicable = (ArrayList) method_hash [name];
1196                         else
1197                                 applicable = (ArrayList) member_hash [name];
1198
1199                         if (applicable == null)
1200                                 return MemberList.Empty;
1201
1202                         ArrayList list = new ArrayList ();
1203
1204                         Timer.StartTimer (TimerType.CachedLookup);
1205
1206                         EntryType type = GetEntryType (mt, bf);
1207
1208                         IMemberContainer current = Container;
1209
1210                         // `applicable' is a list of all members with the given member name `name'
1211                         // in the current class and all its parent classes.  The list is sorted in
1212                         // reverse order due to the way how the cache is initialy created (to speed
1213                         // things up, we're doing a deep-copy of our parent).
1214
1215                         for (int i = applicable.Count-1; i >= 0; i--) {
1216                                 CacheEntry entry = (CacheEntry) applicable [i];
1217
1218                                 // This happens each time we're walking one level up in the class
1219                                 // hierarchy.  If we're doing a DeclaredOnly search, we must abort
1220                                 // the first time this happens (this may already happen in the first
1221                                 // iteration of this loop if there are no members with the name we're
1222                                 // looking for in the current class).
1223                                 if (entry.Container != current) {
1224                                         if (declared_only || DoneSearching (list))
1225                                                 break;
1226
1227                                         current = entry.Container;
1228                                 }
1229
1230                                 // Is the member of the correct type ?
1231                                 if ((entry.EntryType & type & EntryType.MaskType) == 0)
1232                                         continue;
1233
1234                                 // Is the member static/non-static ?
1235                                 if ((entry.EntryType & type & EntryType.MaskStatic) == 0)
1236                                         continue;
1237
1238                                 // Apply the filter to it.
1239                                 if (filter (entry.Member, criteria)) {
1240                                         if ((entry.EntryType & EntryType.MaskType) != EntryType.Method)
1241                                                 do_method_search = false;
1242                                         list.Add (entry.Member);
1243                                 }
1244                         }
1245
1246                         Timer.StopTimer (TimerType.CachedLookup);
1247
1248                         // If we have a method cache and we aren't already doing a method-only
1249                         // search, we restart in method-only search mode if the first match is
1250                         // a method.  This ensures that we return a MemberInfo with the correct
1251                         // ReflectedType for inherited methods.
1252                         if (do_method_search && (list.Count > 0))
1253                                 return FindMembers (MemberTypes.Method, bf, name, filter, criteria);
1254
1255                         return new MemberList (list);
1256                 }
1257         }
1258 }