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                                 // 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                                 //
 104                                 // special case for "protected internal"
 105                                 //
 106
 107                                 if ((parentp & MethodAttributes.FamORAssem) == MethodAttributes.FamORAssem){
 108                                         //
 109                                         // when overriding protected internal, the method can be declared
 110                                         // protected internal only within the same assembly
 111                                         //
 112
 113                                         if ((thisp & MethodAttributes.FamORAssem) == MethodAttributes.FamORAssem){
 114                                                 if (parent.TypeBuilder.Assembly != mb.DeclaringType.Assembly){
 115                                                         //
 116                                                         // assemblies differ - report an error
 117                                                         //
 118
 119                                                         Error_CannotChangeAccessModifiers (parent, mb, name);
 120                                                     ok = false;
 121                                                 } else if (thisp != parentp) {
 122                                                         //
 123                                                         // same assembly, but other attributes differ - report an error
 124                                                         //
 125
 126                                                         Error_CannotChangeAccessModifiers (parent, mb, name);
 127                                                         ok = false;
 128                                                 };
 129                                         } else if ((thisp & MethodAttributes.Family) != MethodAttributes.Family) {
 130                                                 //
 131                                                 // if it's not "protected internal", it must be "protected"
 132                                                 //
 133
 134                                                 Error_CannotChangeAccessModifiers (parent, mb, name);
 135                                                 ok = false;
 136                                         } else if (parent.TypeBuilder.Assembly == mb.DeclaringType.Assembly) {
 137                                                 //
 138                                                 // protected within the same assembly - an error
 139                                                 //
 140                                                 Error_CannotChangeAccessModifiers (parent, mb, name);
 141                                                 ok = false;
 142                                         } else if ((thisp & ~(MethodAttributes.Family | MethodAttributes.FamORAssem)) !=
 143                                                    (parentp & ~(MethodAttributes.Family | MethodAttributes.FamORAssem))) {
 144                                                 //
 145                                                 // protected ok, but other attributes differ - report an error
 146                                                 //
 147                                                 Error_CannotChangeAccessModifiers (parent, mb, name);
 148                                                 ok = false;
 149                                         }
 150                                 } else {
 151                                         if (thisp != parentp){
 152                                                 Error_CannotChangeAccessModifiers (parent, mb, name);
 153                                                 ok = false;
 154                                         }
 155                                 }
 156                         }
 157
 158                         if (mb.IsVirtual || mb.IsAbstract){
 159                                 if ((ModFlags & (Modifiers.NEW | Modifiers.OVERRIDE)) == 0){
 160                                         if (Name != "Finalize"){
 161                                                 Report.Warning (
 162                                                         114, 2, Location, parent.MakeName (Name) +
 163                                                         " hides inherited member `" + name +
 164                                                         "'.  To make the current member override that " +
 165                                                         "implementation, add the override keyword, " +
 166                                                         "otherwise use the new keyword");
 167                                                 ModFlags |= Modifiers.NEW;
 168                                         }
 169                                 }
 170                         } else {
 171                                 if ((ModFlags & (Modifiers.NEW | Modifiers.OVERRIDE)) == 0){
 172                                         if (Name != "Finalize"){
 173                                                 Report.Warning (
 174                                                         108, 1, Location, "The keyword new is required on " +
 175                                                         parent.MakeName (Name) + " because it hides " +
 176                                                         "inherited member `" + name + "'");
 177                                                 ModFlags |= Modifiers.NEW;
 178                                         }
 179                                 }
 180                         }
 181
 182                         return ok;
 183                 }
 184
 185                 public abstract bool Define (TypeContainer parent);
 186
 187                 //
 188                 // Whehter is it ok to use an unsafe pointer in this type container
 189                 //
 190                 public bool UnsafeOK (DeclSpace parent)
 191                 {
 192                         //
 193                         // First check if this MemberCore modifier flags has unsafe set
 194                         //
 195                         if ((ModFlags & Modifiers.UNSAFE) != 0)
 196                                 return true;
 197
 198                         if (parent.UnsafeContext)
 199                                 return true;
 200
 201                         Expression.UnsafeError (Location);
 202                         return false;
 203                 }
 204         }
 205
 206         //
 207         // FIXME: This is temporary outside DeclSpace, because I have to fix a bug
 208         // in MCS that makes it fail the lookup for the enum
 209         //
 210
 211                 /// <summary>
 212                 ///   The result value from adding an declaration into
 213                 ///   a struct or a class
 214                 /// </summary>
 215                 public enum AdditionResult {
 216                         /// <summary>
 217                         /// The declaration has been successfully
 218                         /// added to the declation space.
 219                         /// </summary>
 220                         Success,
 221
 222                         /// <summary>
 223                         ///   The symbol has already been defined.
 224                         /// </summary>
 225                         NameExists,
 226
 227                         /// <summary>
 228                         ///   Returned if the declation being added to the
 229                         ///   name space clashes with its container name.
 230                         ///
 231                         ///   The only exceptions for this are constructors
 232                         ///   and static constructors
 233                         /// </summary>
 234                         EnclosingClash,
 235
 236                         /// <summary>
 237                         ///   Returned if a constructor was created (because syntactically
 238                         ///   it looked like a constructor) but was not (because the name
 239                         ///   of the method is not the same as the container class
 240                         /// </summary>
 241                         NotAConstructor,
 242
 243                         /// <summary>
 244                         ///   This is only used by static constructors to emit the
 245                         ///   error 111, but this error for other things really
 246                         ///   happens at another level for other functions.
 247                         /// </summary>
 248                         MethodExists
 249                 }
 250
 251         /// <summary>
 252         ///   Base class for structs, classes, enumerations and interfaces.
 253         /// </summary>
 254         /// <remarks>
 255         ///   They all create new declaration spaces.  This
 256         ///   provides the common foundation for managing those name
 257         ///   spaces.
 258         /// </remarks>
 259         public abstract class DeclSpace : MemberCore {
 260                 /// <summary>
 261                 ///   this points to the actual definition that is being
 262                 ///   created with System.Reflection.Emit
 263                 /// </summary>
 264                 public TypeBuilder TypeBuilder;
 265
 266                 /// <summary>
 267                 ///   This variable tracks whether we have Closed the type
 268                 /// </summary>
 269                 public bool Created = false;
 270
 271                 //
 272                 // This is the namespace in which this typecontainer
 273                 // was declared.  We use this to resolve names.
 274                 //
 275                 public Namespace Namespace;
 276
 277                 public Hashtable Cache = new Hashtable ();
 278
 279                 public string Basename;
 280
 281                 /// <summary>
 282                 ///   defined_names is used for toplevel objects
 283                 /// </summary>
 284                 protected Hashtable defined_names;
 285
 286                 TypeContainer parent;
 287
 288                 public DeclSpace (TypeContainer parent, string name, Location l)
 289                         : base (name, l)
 290                 {
 291                         Basename = name.Substring (1 + name.LastIndexOf ('.'));
 292                         defined_names = new Hashtable ();
 293                         this.parent = parent;
 294                 }
 295
 296                 /// <summary>
 297                 ///   Returns a status code based purely on the name
 298                 ///   of the member being added
 299                 /// </summary>
 300                 protected AdditionResult IsValid (string basename, string name)
 301                 {
 302                         if (basename == Basename)
 303                                 return AdditionResult.EnclosingClash;
 304
 305                         if (defined_names.Contains (name))
 306                                 return AdditionResult.NameExists;
 307
 308                         return AdditionResult.Success;
 309                 }
 310
 311                 public static int length;
 312                 public static int small;
 313
 314                 /// <summary>
 315                 ///   Introduce @name into this declaration space and
 316                 ///   associates it with the object @o.  Note that for
 317                 ///   methods this will just point to the first method. o
 318                 /// </summary>
 319                 protected void DefineName (string name, object o)
 320                 {
 321                         defined_names.Add (name, o);
 322
 323 #if DEBUGME
 324                         int p = name.LastIndexOf (".");
 325                         int l = name.Length;
 326                         length += l;
 327                         small += l -p;
 328 #endif
 329                 }
 330
 331                 /// <summary>
 332                 ///   Returns the object associated with a given name in the declaration
 333                 ///   space.  This is the inverse operation of `DefineName'
 334                 /// </summary>
 335                 public object GetDefinition (string name)
 336                 {
 337                         return defined_names [name];
 338                 }
 339
 340                 bool in_transit = false;
 341
 342                 /// <summary>
 343                 ///   This function is used to catch recursive definitions
 344                 ///   in declarations.
 345                 /// </summary>
 346                 public bool InTransit {
 347                         get {
 348                                 return in_transit;
 349                         }
 350
 351                         set {
 352                                 in_transit = value;
 353                         }
 354                 }
 355
 356                 public TypeContainer Parent {
 357                         get {
 358                                 return parent;
 359                         }
 360                 }
 361
 362                 /// <summary>
 363                 ///   Looks up the alias for the name
 364                 /// </summary>
 365                 public string LookupAlias (string name)
 366                 {
 367                         if (Namespace != null)
 368                                 return Namespace.LookupAlias (name);
 369                         else
 370                                 return null;
 371                 }
 372
 373                 //
 374                 // root_types contains all the types.  All TopLevel types
 375                 // hence have a parent that points to `root_types', that is
 376                 // why there is a non-obvious test down here.
 377                 //
 378                 public bool IsTopLevel {
 379                         get {
 380                                 if (parent != null){
 381                                         if (parent.parent == null)
 382                                                 return true;
 383                                 }
 384                                 return false;
 385                         }
 386                 }
 387
 388                 public virtual void CloseType ()
 389                 {
 390                         if (!Created){
 391                                 try {
 392                                         TypeBuilder.CreateType ();
 393                                 } catch {
 394                                         //
 395                                         // The try/catch is needed because
 396                                         // nested enumerations fail to load when they
 397                                         // are defined.
 398                                         //
 399                                         // Even if this is the right order (enumerations
 400                                         // declared after types).
 401                                         //
 402                                         // Note that this still creates the type and
 403                                         // it is possible to save it
 404                                 }
 405                                 Created = true;
 406                         }
 407                 }
 408
 409                 /// <remarks>
 410                 ///  Should be overriten by the appropriate declaration space
 411                 /// <remarks>
 412                 public abstract TypeBuilder DefineType ();
 413
 414                 /// <summary>
 415                 ///   Define all members, but don't apply any attributes or do anything which may
 416                 ///   access not-yet-defined classes.  This method also creates the MemberCache.
 417                 /// </summary>
 418                 public abstract bool DefineMembers (TypeContainer parent);
 419
 420                 //
 421                 // Whether this is an `unsafe context'
 422                 //
 423                 public bool UnsafeContext {
 424                         get {
 425                                 if ((ModFlags & Modifiers.UNSAFE) != 0)
 426                                         return true;
 427                                 if (parent != null)
 428                                         return parent.UnsafeContext;
 429                                 return false;
 430                         }
 431                 }
 432
 433                 public static string MakeFQN (string nsn, string name)
 434                 {
 435                         if (nsn == "")
 436                                 return name;
 437                         return String.Concat (nsn, ".", name);
 438                 }
 439
 440                 EmitContext type_resolve_ec;
 441                 EmitContext GetTypeResolveEmitContext (TypeContainer parent, Location loc)
 442                 {
 443                         type_resolve_ec = new EmitContext (parent, this, loc, null, null, ModFlags, false);
 444                         type_resolve_ec.ResolvingTypeTree = true;
 445
 446                         return type_resolve_ec;
 447                 }
 448
 449                 // <summary>
 450                 //    Looks up the type, as parsed into the expression `e'
 451                 // </summary>
 452                 public Type ResolveType (Expression e, bool silent, Location loc)
 453                 {
 454                         if (type_resolve_ec == null)
 455                                 type_resolve_ec = GetTypeResolveEmitContext (parent, loc);
 456                         type_resolve_ec.loc = loc;
 457                         type_resolve_ec.ContainerType = TypeBuilder;
 458
 459                         int errors = Report.Errors;
 460                         Expression d = e.ResolveAsTypeTerminal (type_resolve_ec);
 461
 462                         if (d == null || d.eclass != ExprClass.Type){
 463                                 if (!silent && errors == Report.Errors){
 464                                         Report.Error (246, loc, "Cannot find type `"+ e.ToString () +"'");
 465                                 }
 466                                 return null;
 467                         }
 468
 469                         if (!CheckAccessLevel (d.Type)) {
 470                                 Report. Error (122, loc,  "`" + d.Type + "' " +
 471                                        "is inaccessible because of its protection level");
 472                                 return null;
 473                         }
 474
 475                         return d.Type;
 476                 }
 477
 478                 // <summary>
 479                 //    Resolves the expression `e' for a type, and will recursively define
 480                 //    types.
 481                 // </summary>
 482                 public Expression ResolveTypeExpr (Expression e, bool silent, Location loc)
 483                 {
 484                         if (type_resolve_ec == null)
 485                                 type_resolve_ec = GetTypeResolveEmitContext (parent, loc);
 486                         type_resolve_ec.loc = loc;
 487                         type_resolve_ec.ContainerType = TypeBuilder;
 488
 489                         Expression d = e.ResolveAsTypeTerminal (type_resolve_ec);
 490
 491                         if (d == null || d.eclass != ExprClass.Type){
 492                                 if (!silent){
 493                                         Report.Error (246, loc, "Cannot find type `"+ e +"'");
 494                                 }
 495                                 return null;
 496                         }
 497
 498                         return d;
 499                 }
 500
 501                 public bool CheckAccessLevel (Type check_type)
 502                 {
 503                         if (check_type == TypeBuilder)
 504                                 return true;
 505
 506                         TypeAttributes check_attr = check_type.Attributes & TypeAttributes.VisibilityMask;
 507
 508                         //
 509                         // Broken Microsoft runtime, return public for arrays, no matter what
 510                         // the accessibility is for their underlying class, and they return
 511                         // NonPublic visibility for pointers
 512                         //
 513                         if (check_type.IsArray || check_type.IsPointer)
 514                                 return CheckAccessLevel (check_type.GetElementType ());
 515
 516                         switch (check_attr){
 517                         case TypeAttributes.Public:
 518                                 return true;
 519
 520                         case TypeAttributes.NotPublic:
 521                                 //
 522                                 // This test should probably use the declaringtype.
 523                                 //
 524                                 if (check_type.Assembly == TypeBuilder.Assembly){
 525                                         return true;
 526                                 }
 527                                 return false;
 528
 529                         case TypeAttributes.NestedPublic:
 530                                 return true;
 531
 532                         case TypeAttributes.NestedPrivate:
 533                                 string check_type_name = check_type.FullName;
 534                                 string type_name = TypeBuilder.FullName;
 535
 536                                 int cio = check_type_name.LastIndexOf ("+");
 537                                 string container = check_type_name.Substring (0, cio);
 538
 539                                 //
 540                                 // Check if the check_type is a nested class of the current type
 541                                 //
 542                                 if (check_type_name.StartsWith (type_name + "+")){
 543                                         return true;
 544                                 }
 545
 546                                 if (type_name.StartsWith (container)){
 547                                         return true;
 548                                 }
 549
 550                                 return false;
 551
 552                         case TypeAttributes.NestedFamily:
 553                                 //
 554                                 // Only accessible to methods in current type or any subtypes
 555                                 //
 556                                 return FamilyAccessible (check_type);
 557
 558                         case TypeAttributes.NestedFamANDAssem:
 559                                 return (check_type.Assembly == TypeBuilder.Assembly) &&
 560                                         FamilyAccessible (check_type);
 561
 562                         case TypeAttributes.NestedFamORAssem:
 563                                 return (check_type.Assembly == TypeBuilder.Assembly) ||
 564                                         FamilyAccessible (check_type);
 565
 566                         case TypeAttributes.NestedAssembly:
 567                                 return check_type.Assembly == TypeBuilder.Assembly;
 568                         }
 569
 570                         Console.WriteLine ("HERE: " + check_attr);
 571                         return false;
 572
 573                 }
 574
 575                 protected bool FamilyAccessible (Type check_type)
 576                 {
 577                         Type declaring = check_type.DeclaringType;
 578                         if (TypeBuilder.IsSubclassOf (declaring))
 579                                 return true;
 580
 581                         string check_type_name = check_type.FullName;
 582                         string type_name = TypeBuilder.FullName;
 583
 584                         int cio = check_type_name.LastIndexOf ("+");
 585                         string container = check_type_name.Substring (0, cio);
 586
 587                         //
 588                         // Check if the check_type is a nested class of the current type
 589                         //
 590                         if (check_type_name.StartsWith (container + "+"))
 591                                 return true;
 592
 593                         return false;
 594                 }
 595
 596
 597                 Type LookupInterfaceOrClass (string ns, string name, out bool error)
 598                 {
 599                         DeclSpace parent;
 600                         Type t;
 601
 602                         error = false;
 603
 604                         name = MakeFQN (ns, name);
 605
 606                         t  = TypeManager.LookupType (name);
 607                         if (t != null)
 608                                 return t;
 609
 610                         parent = (DeclSpace) RootContext.Tree.Decls [name];
 611                         if (parent == null)
 612                                 return null;
 613
 614                         t = parent.DefineType ();
 615                         if (t == null){
 616                                 Report.Error (146, Location, "Class definition is circular: `"+name+"'");
 617                                 error = true;
 618                                 return null;
 619                         }
 620                         return t;
 621                 }
 622
 623                 public static void Error_AmbiguousTypeReference (Location loc, string name, Type t1, Type t2)
 624                 {
 625                         Report.Error (104, loc,
 626                                       String.Format ("`{0}' is an ambiguous reference ({1} or {2}) ", name,
 627                                                      t1.FullName, t2.FullName));
 628                 }
 629
 630                 /// <summary>
 631                 ///   GetType is used to resolve type names at the DeclSpace level.
 632                 ///   Use this to lookup class/struct bases, interface bases or
 633                 ///   delegate type references
 634                 /// </summary>
 635                 ///
 636                 /// <remarks>
 637                 ///   Contrast this to LookupType which is used inside method bodies to
 638                 ///   lookup types that have already been defined.  GetType is used
 639                 ///   during the tree resolution process and potentially define
 640                 ///   recursively the type
 641                 /// </remarks>
 642                 public Type FindType (Location loc, string name)
 643                 {
 644                         Type t;
 645                         bool error;
 646
 647                         //
 648                         // For the case the type we are looking for is nested within this one
 649                         // or is in any base class
 650                         //
 651                         DeclSpace containing_ds = this;
 652
 653                         while (containing_ds != null){
 654                                 Type current_type = containing_ds.TypeBuilder;
 655
 656                                 while (current_type != null) {
 657                                         string pre = current_type.FullName;
 658
 659                                         t = LookupInterfaceOrClass (pre, name, out error);
 660                                         if (error)
 661                                                 return null;
 662
 663                                         if (t != null)
 664                                                 return t;
 665
 666                                         current_type = current_type.BaseType;
 667                                 }
 668                                 containing_ds = containing_ds.Parent;
 669                         }
 670
 671                         //
 672                         // Attempt to lookup the class on our namespace and all it's implicit parents
 673                         //
 674                         for (string ns = Namespace.Name; ns != null; ns = RootContext.ImplicitParent (ns)) {
 675                                 t = LookupInterfaceOrClass (ns, name, out error);
 676                                 if (error)
 677                                         return null;
 678
 679                                 if (t != null)
 680                                         return t;
 681                         }
 682
 683                         //
 684                         // Attempt to do a direct unqualified lookup
 685                         //
 686                         t = LookupInterfaceOrClass ("", name, out error);
 687                         if (error)
 688                                 return null;
 689
 690                         if (t != null)
 691                                 return t;
 692
 693                         //
 694                         // Attempt to lookup the class on any of the `using'
 695                         // namespaces
 696                         //
 697
 698                         for (Namespace ns = Namespace; ns != null; ns = ns.Parent){
 699
 700                                 t = LookupInterfaceOrClass (ns.Name, name, out error);
 701                                 if (error)
 702                                         return null;
 703
 704                                 if (t != null)
 705                                         return t;
 706
 707                                 //
 708                                 // Now check the using clause list
 709                                 //
 710                                 ArrayList using_list = ns.UsingTable;
 711
 712                                 if (using_list == null)
 713                                         continue;
 714
 715                                 Type match = null;
 716                                 foreach (Namespace.UsingEntry ue in using_list){
 717                                         match = LookupInterfaceOrClass (ue.Name, name, out error);
 718                                         if (error)
 719                                                 return null;
 720
 721                                         if (match != null){
 722                                                 if (t != null){
 723                                                         Error_AmbiguousTypeReference (loc, name, t, match);
 724                                                         return null;
 725                                                 }
 726
 727                                                 t = match;
 728                                         }
 729                                 }
 730                                 if (t != null)
 731                                         return t;
 732                         }
 733
 734                         //Report.Error (246, Location, "Can not find type `"+name+"'");
 735                         return null;
 736                 }
 737
 738                 /// <remarks>
 739                 ///   This function is broken and not what you're looking for.  It should only
 740                 ///   be used while the type is still being created since it doesn't use the cache
 741                 ///   and relies on the filter doing the member name check.
 742                 /// </remarks>
 743                 public abstract MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 744                                                         MemberFilter filter, object criteria);
 745
 746                 /// <remarks>
 747                 ///   If we have a MemberCache, return it.  This property may return null if the
 748                 ///   class doesn't have a member cache or while it's still being created.
 749                 /// </remarks>
 750                 public abstract MemberCache MemberCache {
 751                         get;
 752                 }
 753         }
 754
 755         /// <summary>
 756         ///   This is a readonly list of MemberInfo's.
 757         /// </summary>
 758         public class MemberList : IList {
 759                 public readonly IList List;
 760                 int count;
 761
 762                 /// <summary>
 763                 ///   Create a new MemberList from the given IList.
 764                 /// </summary>
 765                 public MemberList (IList list)
 766                 {
 767                         if (list != null)
 768                                 this.List = list;
 769                         else
 770                                 this.List = new ArrayList ();
 771                         count = List.Count;
 772                 }
 773
 774                 /// <summary>
 775                 ///   Concatenate the ILists `first' and `second' to a new MemberList.
 776                 /// </summary>
 777                 public MemberList (IList first, IList second)
 778                 {
 779                         ArrayList list = new ArrayList ();
 780                         list.AddRange (first);
 781                         list.AddRange (second);
 782                         count = list.Count;
 783                         List = list;
 784                 }
 785
 786                 public static readonly MemberList Empty = new MemberList (new ArrayList ());
 787
 788                 /// <summary>
 789                 ///   Cast the MemberList into a MemberInfo[] array.
 790                 /// </summary>
 791                 /// <remarks>
 792                 ///   This is an expensive operation, only use it if it's really necessary.
 793                 /// </remarks>
 794                 public static explicit operator MemberInfo [] (MemberList list)
 795                 {
 796                         Timer.StartTimer (TimerType.MiscTimer);
 797                         MemberInfo [] result = new MemberInfo [list.Count];
 798                         list.CopyTo (result, 0);
 799                         Timer.StopTimer (TimerType.MiscTimer);
 800                         return result;
 801                 }
 802
 803                 // ICollection
 804
 805                 public int Count {
 806                         get {
 807                                 return count;
 808                         }
 809                 }
 810
 811                 public bool IsSynchronized {
 812                         get {
 813                                 return List.IsSynchronized;
 814                         }
 815                 }
 816
 817                 public object SyncRoot {
 818                         get {
 819                                 return List.SyncRoot;
 820                         }
 821                 }
 822
 823                 public void CopyTo (Array array, int index)
 824                 {
 825                         List.CopyTo (array, index);
 826                 }
 827
 828                 // IEnumerable
 829
 830                 public IEnumerator GetEnumerator ()
 831                 {
 832                         return List.GetEnumerator ();
 833                 }
 834
 835                 // IList
 836
 837                 public bool IsFixedSize {
 838                         get {
 839                                 return true;
 840                         }
 841                 }
 842
 843                 public bool IsReadOnly {
 844                         get {
 845                                 return true;
 846                         }
 847                 }
 848
 849                 object IList.this [int index] {
 850                         get {
 851                                 return List [index];
 852                         }
 853
 854                         set {
 855                                 throw new NotSupportedException ();
 856                         }
 857                 }
 858
 859                 // FIXME: try to find out whether we can avoid the cast in this indexer.
 860                 public MemberInfo this [int index] {
 861                         get {
 862                                 return (MemberInfo) List [index];
 863                         }
 864                 }
 865
 866                 public int Add (object value)
 867                 {
 868                         throw new NotSupportedException ();
 869                 }
 870
 871                 public void Clear ()
 872                 {
 873                         throw new NotSupportedException ();
 874                 }
 875
 876                 public bool Contains (object value)
 877                 {
 878                         return List.Contains (value);
 879                 }
 880
 881                 public int IndexOf (object value)
 882                 {
 883                         return List.IndexOf (value);
 884                 }
 885
 886                 public void Insert (int index, object value)
 887                 {
 888                         throw new NotSupportedException ();
 889                 }
 890
 891                 public void Remove (object value)
 892                 {
 893                         throw new NotSupportedException ();
 894                 }
 895
 896                 public void RemoveAt (int index)
 897                 {
 898                         throw new NotSupportedException ();
 899                 }
 900         }
 901
 902         /// <summary>
 903         ///   This interface is used to get all members of a class when creating the
 904         ///   member cache.  It must be implemented by all DeclSpace derivatives which
 905         ///   want to support the member cache and by TypeHandle to get caching of
 906         ///   non-dynamic types.
 907         /// </summary>
 908         public interface IMemberContainer {
 909                 /// <summary>
 910                 ///   The name of the IMemberContainer.  This is only used for
 911                 ///   debugging purposes.
 912                 /// </summary>
 913                 string Name {
 914                         get;
 915                 }
 916
 917                 /// <summary>
 918                 ///   The type of this IMemberContainer.
 919                 /// </summary>
 920                 Type Type {
 921                         get;
 922                 }
 923
 924                 /// <summary>
 925                 ///   Returns the IMemberContainer of the parent class or null if this
 926                 ///   is an interface or TypeManger.object_type.
 927                 ///   This is used when creating the member cache for a class to get all
 928                 ///   members from the parent class.
 929                 /// </summary>
 930                 IMemberContainer Parent {
 931                         get;
 932                 }
 933
 934                 /// <summary>
 935                 ///   Whether this is an interface.
 936                 /// </summary>
 937                 bool IsInterface {
 938                         get;
 939                 }
 940
 941                 /// <summary>
 942                 ///   Returns all members of this class with the corresponding MemberTypes
 943                 ///   and BindingFlags.
 944                 /// </summary>
 945                 /// <remarks>
 946                 ///   When implementing this method, make sure not to return any inherited
 947                 ///   members and check the MemberTypes and BindingFlags properly.
 948                 ///   Unfortunately, System.Reflection is lame and doesn't provide a way to
 949                 ///   get the BindingFlags (static/non-static,public/non-public) in the
 950                 ///   MemberInfo class, but the cache needs this information.  That's why
 951                 ///   this method is called multiple times with different BindingFlags.
 952                 /// </remarks>
 953                 MemberList GetMembers (MemberTypes mt, BindingFlags bf);
 954
 955                 /// <summary>
 956                 ///   Return the container's member cache.
 957                 /// </summary>
 958                 MemberCache MemberCache {
 959                         get;
 960                 }
 961         }
 962
 963         /// <summary>
 964         ///   The MemberCache is used by dynamic and non-dynamic types to speed up
 965         ///   member lookups.  It has a member name based hash table; it maps each member
 966         ///   name to a list of CacheEntry objects.  Each CacheEntry contains a MemberInfo
 967         ///   and the BindingFlags that were initially used to get it.  The cache contains
 968         ///   all members of the current class and all inherited members.  If this cache is
 969         ///   for an interface types, it also contains all inherited members.
 970         ///
 971         ///   There are two ways to get a MemberCache:
 972         ///   * if this is a dynamic type, lookup the corresponding DeclSpace and then
 973         ///     use the DeclSpace.MemberCache property.
 974         ///   * if this not a dynamic type, call TypeHandle.GetTypeHandle() to get a
 975         ///     TypeHandle instance for the type and then use TypeHandle.MemberCache.
 976         /// </summary>
 977         public class MemberCache {
 978                 public readonly IMemberContainer Container;
 979                 protected Hashtable member_hash;
 980                 protected Hashtable method_hash;
 981                 protected Hashtable interface_hash;
 982
 983                 /// <summary>
 984                 ///   Create a new MemberCache for the given IMemberContainer `container'.
 985                 /// </summary>
 986                 public MemberCache (IMemberContainer container)
 987                 {
 988                         this.Container = container;
 989
 990                         Timer.IncrementCounter (CounterType.MemberCache);
 991                         Timer.StartTimer (TimerType.CacheInit);
 992
 993                         interface_hash = new Hashtable ();
 994
 995                         // If we have a parent class (we have a parent class unless we're
 996                         // TypeManager.object_type), we deep-copy its MemberCache here.
 997                         if (Container.Parent != null)
 998                                 member_hash = SetupCache (Container.Parent.MemberCache);
 999                         else if (Container.IsInterface)
1000                                 member_hash = SetupCacheForInterface ();
1001                         else
1002                                 member_hash = new Hashtable ();
1003
1004                         // If this is neither a dynamic type nor an interface, create a special
1005                         // method cache with all declared and inherited methods.
1006                         Type type = container.Type;
1007                         if (!(type is TypeBuilder) && !type.IsInterface) {
1008                                 method_hash = new Hashtable ();
1009                                 AddMethods (type);
1010                         }
1011
1012                         // Add all members from the current class.
1013                         AddMembers (Container);
1014
1015                         Timer.StopTimer (TimerType.CacheInit);
1016                 }
1017
1018                 /// <summary>
1019                 ///   Bootstrap this member cache by doing a deep-copy of our parent.
1020                 /// </summary>
1021                 Hashtable SetupCache (MemberCache parent)
1022                 {
1023                         Hashtable hash = new Hashtable ();
1024
1025                         IDictionaryEnumerator it = parent.member_hash.GetEnumerator ();
1026                         while (it.MoveNext ()) {
1027                                 hash [it.Key] = ((ArrayList) it.Value).Clone ();
1028                         }
1029
1030                         return hash;
1031                 }
1032
1033                 void AddInterfaces (MemberCache parent)
1034                 {
1035                         foreach (Type iface in parent.interface_hash.Keys) {
1036                                 if (!interface_hash.Contains (iface))
1037                                         interface_hash.Add (iface, true);
1038                         }
1039                 }
1040
1041                 /// <summary>
1042                 ///   Add the contents of `new_hash' to `hash'.
1043                 /// </summary>
1044                 void AddHashtable (Hashtable hash, Hashtable new_hash)
1045                 {
1046                         IDictionaryEnumerator it = new_hash.GetEnumerator ();
1047                         while (it.MoveNext ()) {
1048                                 ArrayList list = (ArrayList) hash [it.Key];
1049                                 if (list != null)
1050                                         list.AddRange ((ArrayList) it.Value);
1051                                 else
1052                                         hash [it.Key] = ((ArrayList) it.Value).Clone ();
1053                         }
1054                 }
1055
1056                 /// <summary>
1057                 ///   Bootstrap the member cache for an interface type.
1058                 ///   Type.GetMembers() won't return any inherited members for interface types,
1059                 ///   so we need to do this manually.  Interfaces also inherit from System.Object.
1060                 /// </summary>
1061                 Hashtable SetupCacheForInterface ()
1062                 {
1063                         Hashtable hash = SetupCache (TypeHandle.ObjectType.MemberCache);
1064                         Type [] ifaces = TypeManager.GetInterfaces (Container.Type);
1065
1066                         foreach (Type iface in ifaces) {
1067                                 if (interface_hash.Contains (iface))
1068                                         continue;
1069                                 interface_hash.Add (iface, true);
1070
1071                                 IMemberContainer iface_container =
1072                                         TypeManager.LookupMemberContainer (iface);
1073
1074                                 MemberCache iface_cache = iface_container.MemberCache;
1075                                 AddHashtable (hash, iface_cache.member_hash);
1076                                 AddInterfaces (iface_cache);
1077                         }
1078
1079                         return hash;
1080                 }
1081
1082                 /// <summary>
1083                 ///   Add all members from class `container' to the cache.
1084                 /// </summary>
1085                 void AddMembers (IMemberContainer container)
1086                 {
1087                         // We need to call AddMembers() with a single member type at a time
1088                         // to get the member type part of CacheEntry.EntryType right.
1089                         AddMembers (MemberTypes.Constructor, container);
1090                         AddMembers (MemberTypes.Field, container);
1091                         AddMembers (MemberTypes.Method, container);
1092                         AddMembers (MemberTypes.Property, container);
1093                         AddMembers (MemberTypes.Event, container);
1094                         // Nested types are returned by both Static and Instance searches.
1095                         AddMembers (MemberTypes.NestedType,
1096                                     BindingFlags.Static | BindingFlags.Public, container);
1097                         AddMembers (MemberTypes.NestedType,
1098                                     BindingFlags.Static | BindingFlags.NonPublic, container);
1099                 }
1100
1101                 void AddMembers (MemberTypes mt, IMemberContainer container)
1102                 {
1103                         AddMembers (mt, BindingFlags.Static | BindingFlags.Public, container);
1104                         AddMembers (mt, BindingFlags.Static | BindingFlags.NonPublic, container);
1105                         AddMembers (mt, BindingFlags.Instance | BindingFlags.Public, container);
1106                         AddMembers (mt, BindingFlags.Instance | BindingFlags.NonPublic, container);
1107                 }
1108
1109                 /// <summary>
1110                 ///   Add all members from class `container' with the requested MemberTypes and
1111                 ///   BindingFlags to the cache.  This method is called multiple times with different
1112                 ///   MemberTypes and BindingFlags.
1113                 /// </summary>
1114                 void AddMembers (MemberTypes mt, BindingFlags bf, IMemberContainer container)
1115                 {
1116                         MemberList members = container.GetMembers (mt, bf);
1117                         BindingFlags new_bf = (container == Container) ?
1118                                 bf | BindingFlags.DeclaredOnly : bf;
1119
1120                         foreach (MemberInfo member in members) {
1121                                 string name = member.Name;
1122
1123                                 // We use a name-based hash table of ArrayList's.
1124                                 ArrayList list = (ArrayList) member_hash [name];
1125                                 if (list == null) {
1126                                         list = new ArrayList ();
1127                                         member_hash.Add (name, list);
1128                                 }
1129
1130                                 // When this method is called for the current class, the list will
1131                                 // already contain all inherited members from our parent classes.
1132                                 // We cannot add new members in front of the list since this'd be an
1133                                 // expensive operation, that's why the list is sorted in reverse order
1134                                 // (ie. members from the current class are coming last).
1135                                 list.Add (new CacheEntry (container, member, mt, bf));
1136                         }
1137                 }
1138
1139                 /// <summary>
1140                 ///   Add all declared and inherited methods from class `type' to the method cache.
1141                 /// </summary>
1142                 void AddMethods (Type type)
1143                 {
1144                         AddMethods (BindingFlags.Static | BindingFlags.Public |
1145                                     BindingFlags.FlattenHierarchy, type);
1146                         AddMethods (BindingFlags.Static | BindingFlags.NonPublic |
1147                                     BindingFlags.FlattenHierarchy, type);
1148                         AddMethods (BindingFlags.Instance | BindingFlags.Public, type);
1149                         AddMethods (BindingFlags.Instance | BindingFlags.NonPublic, type);
1150                 }
1151
1152                 void AddMethods (BindingFlags bf, Type type)
1153                 {
1154                         MemberInfo [] members = type.GetMethods (bf);
1155
1156                         foreach (MethodBase member in members) {
1157                                 string name = member.Name;
1158
1159                                 // Varargs methods aren't allowed in C# code.
1160                                 if ((member.CallingConvention & CallingConventions.VarArgs) != 0)
1161                                         continue;
1162
1163                                 // We use a name-based hash table of ArrayList's.
1164                                 ArrayList list = (ArrayList) method_hash [name];
1165                                 if (list == null) {
1166                                         list = new ArrayList ();
1167                                         method_hash.Add (name, list);
1168                                 }
1169
1170                                 // Unfortunately, the elements returned by Type.GetMethods() aren't
1171                                 // sorted so we need to do this check for every member.
1172                                 BindingFlags new_bf = bf;
1173                                 if (member.DeclaringType == type)
1174                                         new_bf |= BindingFlags.DeclaredOnly;
1175
1176                                 list.Add (new CacheEntry (Container, member, MemberTypes.Method, new_bf));
1177                         }
1178                 }
1179
1180                 /// <summary>
1181                 ///   Compute and return a appropriate `EntryType' magic number for the given
1182                 ///   MemberTypes and BindingFlags.
1183                 /// </summary>
1184                 protected static EntryType GetEntryType (MemberTypes mt, BindingFlags bf)
1185                 {
1186                         EntryType type = EntryType.None;
1187
1188                         if ((mt & MemberTypes.Constructor) != 0)
1189                                 type |= EntryType.Constructor;
1190                         if ((mt & MemberTypes.Event) != 0)
1191                                 type |= EntryType.Event;
1192                         if ((mt & MemberTypes.Field) != 0)
1193                                 type |= EntryType.Field;
1194                         if ((mt & MemberTypes.Method) != 0)
1195                                 type |= EntryType.Method;
1196                         if ((mt & MemberTypes.Property) != 0)
1197                                 type |= EntryType.Property;
1198                         // Nested types are returned by static and instance searches.
1199                         if ((mt & MemberTypes.NestedType) != 0)
1200                                 type |= EntryType.NestedType | EntryType.Static | EntryType.Instance;
1201
1202                         if ((bf & BindingFlags.Instance) != 0)
1203                                 type |= EntryType.Instance;
1204                         if ((bf & BindingFlags.Static) != 0)
1205                                 type |= EntryType.Static;
1206                         if ((bf & BindingFlags.Public) != 0)
1207                                 type |= EntryType.Public;
1208                         if ((bf & BindingFlags.NonPublic) != 0)
1209                                 type |= EntryType.NonPublic;
1210                         if ((bf & BindingFlags.DeclaredOnly) != 0)
1211                                 type |= EntryType.Declared;
1212
1213                         return type;
1214                 }
1215
1216                 /// <summary>
1217                 ///   The `MemberTypes' enumeration type is a [Flags] type which means that it may
1218                 ///   denote multiple member types.  Returns true if the given flags value denotes a
1219                 ///   single member types.
1220                 /// </summary>
1221                 public static bool IsSingleMemberType (MemberTypes mt)
1222                 {
1223                         switch (mt) {
1224                         case MemberTypes.Constructor:
1225                         case MemberTypes.Event:
1226                         case MemberTypes.Field:
1227                         case MemberTypes.Method:
1228                         case MemberTypes.Property:
1229                         case MemberTypes.NestedType:
1230                                 return true;
1231
1232                         default:
1233                                 return false;
1234                         }
1235                 }
1236
1237                 /// <summary>
1238                 ///   We encode the MemberTypes and BindingFlags of each members in a "magic"
1239                 ///   number to speed up the searching process.
1240                 /// </summary>
1241                 [Flags]
1242                 protected enum EntryType {
1243                         None            = 0x000,
1244
1245                         Instance        = 0x001,
1246                         Static          = 0x002,
1247                         MaskStatic      = Instance|Static,
1248
1249                         Public          = 0x004,
1250                         NonPublic       = 0x008,
1251                         MaskProtection  = Public|NonPublic,
1252
1253                         Declared        = 0x010,
1254
1255                         Constructor     = 0x020,
1256                         Event           = 0x040,
1257                         Field           = 0x080,
1258                         Method          = 0x100,
1259                         Property        = 0x200,
1260                         NestedType      = 0x400,
1261
1262                         MaskType        = Constructor|Event|Field|Method|Property|NestedType
1263                 }
1264
1265                 protected struct CacheEntry {
1266                         public readonly IMemberContainer Container;
1267                         public readonly EntryType EntryType;
1268                         public readonly MemberInfo Member;
1269
1270                         public CacheEntry (IMemberContainer container, MemberInfo member,
1271                                            MemberTypes mt, BindingFlags bf)
1272                         {
1273                                 this.Container = container;
1274                                 this.Member = member;
1275                                 this.EntryType = GetEntryType (mt, bf);
1276                         }
1277                 }
1278
1279                 /// <summary>
1280                 ///   This is called each time we're walking up one level in the class hierarchy
1281                 ///   and checks whether we can abort the search since we've already found what
1282                 ///   we were looking for.
1283                 /// </summary>
1284                 protected bool DoneSearching (ArrayList list)
1285                 {
1286                         //
1287                         // We've found exactly one member in the current class and it's not
1288                         // a method or constructor.
1289                         //
1290                         if (list.Count == 1 && !(list [0] is MethodBase))
1291                                 return true;
1292
1293                         //
1294                         // Multiple properties: we query those just to find out the indexer
1295                         // name
1296                         //
1297                         if ((list.Count > 0) && (list [0] is PropertyInfo))
1298                                 return true;
1299
1300                         return false;
1301                 }
1302
1303                 /// <summary>
1304                 ///   Looks up members with name `name'.  If you provide an optional
1305                 ///   filter function, it'll only be called with members matching the
1306                 ///   requested member name.
1307                 ///
1308                 ///   This method will try to use the cache to do the lookup if possible.
1309                 ///
1310                 ///   Unlike other FindMembers implementations, this method will always
1311                 ///   check all inherited members - even when called on an interface type.
1312                 ///
1313                 ///   If you know that you're only looking for methods, you should use
1314                 ///   MemberTypes.Method alone since this speeds up the lookup a bit.
1315                 ///   When doing a method-only search, it'll try to use a special method
1316                 ///   cache (unless it's a dynamic type or an interface) and the returned
1317                 ///   MemberInfo's will have the correct ReflectedType for inherited methods.
1318                 ///   The lookup process will automatically restart itself in method-only
1319                 ///   search mode if it discovers that it's about to return methods.
1320                 /// </summary>
1321                 public MemberList FindMembers (MemberTypes mt, BindingFlags bf, string name,
1322                                                MemberFilter filter, object criteria)
1323                 {
1324                         bool declared_only = (bf & BindingFlags.DeclaredOnly) != 0;
1325                         bool method_search = mt == MemberTypes.Method;
1326                         // If we have a method cache and we aren't already doing a method-only search,
1327                         // then we restart a method search if the first match is a method.
1328                         bool do_method_search = !method_search && (method_hash != null);
1329
1330                         ArrayList applicable;
1331
1332                         // If this is a method-only search, we try to use the method cache if
1333                         // possible; a lookup in the method cache will return a MemberInfo with
1334                         // the correct ReflectedType for inherited methods.
1335
1336                         if (method_search && (method_hash != null))
1337                                 applicable = (ArrayList) method_hash [name];
1338                         else
1339                                 applicable = (ArrayList) member_hash [name];
1340
1341                         if (applicable == null)
1342                                 return MemberList.Empty;
1343
1344                         ArrayList list = new ArrayList ();
1345
1346                         Timer.StartTimer (TimerType.CachedLookup);
1347
1348                         EntryType type = GetEntryType (mt, bf);
1349
1350                         IMemberContainer current = Container;
1351
1352                         // `applicable' is a list of all members with the given member name `name'
1353                         // in the current class and all its parent classes.  The list is sorted in
1354                         // reverse order due to the way how the cache is initialy created (to speed
1355                         // things up, we're doing a deep-copy of our parent).
1356
1357                         for (int i = applicable.Count-1; i >= 0; i--) {
1358                                 CacheEntry entry = (CacheEntry) applicable [i];
1359
1360                                 // This happens each time we're walking one level up in the class
1361                                 // hierarchy.  If we're doing a DeclaredOnly search, we must abort
1362                                 // the first time this happens (this may already happen in the first
1363                                 // iteration of this loop if there are no members with the name we're
1364                                 // looking for in the current class).
1365                                 if (entry.Container != current) {
1366                                         if (declared_only || DoneSearching (list))
1367                                                 break;
1368
1369                                         current = entry.Container;
1370                                 }
1371
1372                                 // Is the member of the correct type ?
1373                                 if ((entry.EntryType & type & EntryType.MaskType) == 0)
1374                                         continue;
1375
1376                                 // Is the member static/non-static ?
1377                                 if ((entry.EntryType & type & EntryType.MaskStatic) == 0)
1378                                         continue;
1379
1380                                 // Apply the filter to it.
1381                                 if (filter (entry.Member, criteria)) {
1382                                         if ((entry.EntryType & EntryType.MaskType) != EntryType.Method)
1383                                                 do_method_search = false;
1384                                         list.Add (entry.Member);
1385                                 }
1386                         }
1387
1388                         Timer.StopTimer (TimerType.CachedLookup);
1389
1390                         // If we have a method cache and we aren't already doing a method-only
1391                         // search, we restart in method-only search mode if the first match is
1392                         // a method.  This ensures that we return a MemberInfo with the correct
1393                         // ReflectedType for inherited methods.
1394                         if (do_method_search && (list.Count > 0)){
1395                                 return FindMembers (MemberTypes.Method, bf, name, filter, criteria);
1396                         }
1397
1398                         return new MemberList (list);
1399                 }
1400         }
1401 }