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 name)
 301                 {
 302                         if (name == 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.Resolve (type_resolve_ec, ResolveFlags.Type);
 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, "`" + 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
 487                         Expression d = e.Resolve (type_resolve_ec, ResolveFlags.Type);
 488
 489                         if (d == null || d.eclass != ExprClass.Type){
 490                                 if (!silent){
 491                                         Report.Error (246, loc, "Cannot find type `"+ e +"'");
 492                                 }
 493                                 return null;
 494                         }
 495
 496                         return d;
 497                 }
 498
 499                 bool CheckAccessLevel (Type check_type)
 500                 {
 501                         //
 502                         // Broken Microsoft runtime, return public for arrays, no matter what
 503                         // the accessibility is for their underlying class
 504                         //
 505                         if (check_type.IsPublic){
 506                                 if (check_type.IsArray)
 507                                         return CheckAccessLevel (check_type.GetElementType ());
 508
 509                                 return true;
 510                         }
 511
 512                         if (check_type.IsNestedPublic)
 513                                 return true;
 514
 515                         if (check_type.Assembly == TypeBuilder.Assembly)
 516                                 return true;
 517
 518                         //
 519                         // Broken Microsoft runtime: They set the accessibility of
 520                         // pointers to NonPublic, even if their ElementType is accessible
 521                         // in some form.
 522                         //
 523                         if (check_type.IsPointer)
 524                                 return CheckAccessLevel (check_type.GetElementType ());
 525
 526                         return false;
 527
 528                 }
 529
 530
 531                 Type LookupInterfaceOrClass (string ns, string name, out bool error)
 532                 {
 533                         DeclSpace parent;
 534                         Type t;
 535
 536                         error = false;
 537                         name = MakeFQN (ns, name);
 538
 539                         t  = TypeManager.LookupType (name);
 540                         if (t != null)
 541                                 return t;
 542
 543                         parent = (DeclSpace) RootContext.Tree.Decls [name];
 544                         if (parent == null)
 545                                 return null;
 546
 547                         t = parent.DefineType ();
 548                         if (t == null){
 549                                 Report.Error (146, Location, "Class definition is circular: `"+name+"'");
 550                                 error = true;
 551                                 return null;
 552                         }
 553                         return t;
 554                 }
 555
 556                 public static void Error_AmbiguousTypeReference (Location loc, string name, Type t1, Type t2)
 557                 {
 558                         Report.Error (104, loc,
 559                                       String.Format ("`{0}' is an ambiguous reference ({1} or {2}) ", name,
 560                                                      t1.FullName, t2.FullName));
 561                 }
 562
 563                 /// <summary>
 564                 ///   GetType is used to resolve type names at the DeclSpace level.
 565                 ///   Use this to lookup class/struct bases, interface bases or
 566                 ///   delegate type references
 567                 /// </summary>
 568                 ///
 569                 /// <remarks>
 570                 ///   Contrast this to LookupType which is used inside method bodies to
 571                 ///   lookup types that have already been defined.  GetType is used
 572                 ///   during the tree resolution process and potentially define
 573                 ///   recursively the type
 574                 /// </remarks>
 575                 public Type FindType (Location loc, string name)
 576                 {
 577                         Type t;
 578                         bool error;
 579
 580                         //
 581                         // For the case the type we are looking for is nested within this one
 582                         // or is in any base class
 583                         //
 584                         DeclSpace containing_ds = this;
 585
 586                         while (containing_ds != null){
 587                                 Type current_type = containing_ds.TypeBuilder;
 588
 589                                 while (current_type != null) {
 590                                         string pre = current_type.FullName;
 591
 592                                         t = LookupInterfaceOrClass (pre, name, out error);
 593                                         if (error)
 594                                                 return null;
 595
 596                                         if (t != null)
 597                                                 return t;
 598
 599                                         current_type = current_type.BaseType;
 600                                 }
 601                                 containing_ds = containing_ds.Parent;
 602                         }
 603
 604                         //
 605                         // Attempt to lookup the class on our namespace and all it's implicit parents
 606                         //
 607                         for (string ns = Namespace.Name; ns != null; ns = RootContext.ImplicitParent (ns)) {
 608
 609                                 t = LookupInterfaceOrClass (ns, name, out error);
 610                                 if (error)
 611                                         return null;
 612
 613                                 if (t != null)
 614                                         return t;
 615                         }
 616
 617                         //
 618                         // Attempt to do a direct unqualified lookup
 619                         //
 620                         t = LookupInterfaceOrClass ("", name, out error);
 621                         if (error)
 622                                 return null;
 623
 624                         if (t != null)
 625                                 return t;
 626
 627                         //
 628                         // Attempt to lookup the class on any of the `using'
 629                         // namespaces
 630                         //
 631
 632                         for (Namespace ns = Namespace; ns != null; ns = ns.Parent){
 633
 634                                 t = LookupInterfaceOrClass (ns.Name, name, out error);
 635                                 if (error)
 636                                         return null;
 637
 638                                 if (t != null)
 639                                         return t;
 640
 641                                 //
 642                                 // Now check the using clause list
 643                                 //
 644                                 ArrayList using_list = ns.UsingTable;
 645
 646                                 if (using_list == null)
 647                                         continue;
 648
 649                                 Type match = null;
 650                                 foreach (Namespace.UsingEntry ue in using_list){
 651                                         match = LookupInterfaceOrClass (ue.Name, name, out error);
 652                                         if (error)
 653                                                 return null;
 654
 655                                         if (match != null){
 656                                                 if (t != null){
 657                                                         Error_AmbiguousTypeReference (loc, name, t, match);
 658                                                         return null;
 659                                                 }
 660
 661                                                 t = match;
 662                                                 ue.Used = true;
 663                                         }
 664                                 }
 665                                 if (t != null)
 666                                         return t;
 667                         }
 668
 669                         //Report.Error (246, Location, "Can not find type `"+name+"'");
 670                         return null;
 671                 }
 672
 673                 /// <remarks>
 674                 ///   This function is broken and not what you're looking for.  It should only
 675                 ///   be used while the type is still being created since it doesn't use the cache
 676                 ///   and relies on the filter doing the member name check.
 677                 /// </remarks>
 678                 public abstract MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 679                                                         MemberFilter filter, object criteria);
 680
 681                 /// <remarks>
 682                 ///   If we have a MemberCache, return it.  This property may return null if the
 683                 ///   class doesn't have a member cache or while it's still being created.
 684                 /// </remarks>
 685                 public abstract MemberCache MemberCache {
 686                         get;
 687                 }
 688         }
 689
 690         /// <summary>
 691         ///   This is a readonly list of MemberInfo's.
 692         /// </summary>
 693         public class MemberList : IList {
 694                 public readonly IList List;
 695                 int count;
 696
 697                 /// <summary>
 698                 ///   Create a new MemberList from the given IList.
 699                 /// </summary>
 700                 public MemberList (IList list)
 701                 {
 702                         if (list != null)
 703                                 this.List = list;
 704                         else
 705                                 this.List = new ArrayList ();
 706                         count = List.Count;
 707                 }
 708
 709                 /// <summary>
 710                 ///   Concatenate the ILists `first' and `second' to a new MemberList.
 711                 /// </summary>
 712                 public MemberList (IList first, IList second)
 713                 {
 714                         ArrayList list = new ArrayList ();
 715                         list.AddRange (first);
 716                         list.AddRange (second);
 717                         count = list.Count;
 718                         List = list;
 719                 }
 720
 721                 public static readonly MemberList Empty = new MemberList (new ArrayList ());
 722
 723                 /// <summary>
 724                 ///   Cast the MemberList into a MemberInfo[] array.
 725                 /// </summary>
 726                 /// <remarks>
 727                 ///   This is an expensive operation, only use it if it's really necessary.
 728                 /// </remarks>
 729                 public static explicit operator MemberInfo [] (MemberList list)
 730                 {
 731                         Timer.StartTimer (TimerType.MiscTimer);
 732                         MemberInfo [] result = new MemberInfo [list.Count];
 733                         list.CopyTo (result, 0);
 734                         Timer.StopTimer (TimerType.MiscTimer);
 735                         return result;
 736                 }
 737
 738                 // ICollection
 739
 740                 public int Count {
 741                         get {
 742                                 return count;
 743                         }
 744                 }
 745
 746                 public bool IsSynchronized {
 747                         get {
 748                                 return List.IsSynchronized;
 749                         }
 750                 }
 751
 752                 public object SyncRoot {
 753                         get {
 754                                 return List.SyncRoot;
 755                         }
 756                 }
 757
 758                 public void CopyTo (Array array, int index)
 759                 {
 760                         List.CopyTo (array, index);
 761                 }
 762
 763                 // IEnumerable
 764
 765                 public IEnumerator GetEnumerator ()
 766                 {
 767                         return List.GetEnumerator ();
 768                 }
 769
 770                 // IList
 771
 772                 public bool IsFixedSize {
 773                         get {
 774                                 return true;
 775                         }
 776                 }
 777
 778                 public bool IsReadOnly {
 779                         get {
 780                                 return true;
 781                         }
 782                 }
 783
 784                 object IList.this [int index] {
 785                         get {
 786                                 return List [index];
 787                         }
 788
 789                         set {
 790                                 throw new NotSupportedException ();
 791                         }
 792                 }
 793
 794                 // FIXME: try to find out whether we can avoid the cast in this indexer.
 795                 public MemberInfo this [int index] {
 796                         get {
 797                                 return (MemberInfo) List [index];
 798                         }
 799                 }
 800
 801                 public int Add (object value)
 802                 {
 803                         throw new NotSupportedException ();
 804                 }
 805
 806                 public void Clear ()
 807                 {
 808                         throw new NotSupportedException ();
 809                 }
 810
 811                 public bool Contains (object value)
 812                 {
 813                         return List.Contains (value);
 814                 }
 815
 816                 public int IndexOf (object value)
 817                 {
 818                         return List.IndexOf (value);
 819                 }
 820
 821                 public void Insert (int index, object value)
 822                 {
 823                         throw new NotSupportedException ();
 824                 }
 825
 826                 public void Remove (object value)
 827                 {
 828                         throw new NotSupportedException ();
 829                 }
 830
 831                 public void RemoveAt (int index)
 832                 {
 833                         throw new NotSupportedException ();
 834                 }
 835         }
 836
 837         /// <summary>
 838         ///   This interface is used to get all members of a class when creating the
 839         ///   member cache.  It must be implemented by all DeclSpace derivatives which
 840         ///   want to support the member cache and by TypeHandle to get caching of
 841         ///   non-dynamic types.
 842         /// </summary>
 843         public interface IMemberContainer {
 844                 /// <summary>
 845                 ///   The name of the IMemberContainer.  This is only used for
 846                 ///   debugging purposes.
 847                 /// </summary>
 848                 string Name {
 849                         get;
 850                 }
 851
 852                 /// <summary>
 853                 ///   The type of this IMemberContainer.
 854                 /// </summary>
 855                 Type Type {
 856                         get;
 857                 }
 858
 859                 /// <summary>
 860                 ///   Returns the IMemberContainer of the parent class or null if this
 861                 ///   is an interface or TypeManger.object_type.
 862                 ///   This is used when creating the member cache for a class to get all
 863                 ///   members from the parent class.
 864                 /// </summary>
 865                 IMemberContainer Parent {
 866                         get;
 867                 }
 868
 869                 /// <summary>
 870                 ///   Whether this is an interface.
 871                 /// </summary>
 872                 bool IsInterface {
 873                         get;
 874                 }
 875
 876                 /// <summary>
 877                 ///   Returns all members of this class with the corresponding MemberTypes
 878                 ///   and BindingFlags.
 879                 /// </summary>
 880                 /// <remarks>
 881                 ///   When implementing this method, make sure not to return any inherited
 882                 ///   members and check the MemberTypes and BindingFlags properly.
 883                 ///   Unfortunately, System.Reflection is lame and doesn't provide a way to
 884                 ///   get the BindingFlags (static/non-static,public/non-public) in the
 885                 ///   MemberInfo class, but the cache needs this information.  That's why
 886                 ///   this method is called multiple times with different BindingFlags.
 887                 /// </remarks>
 888                 MemberList GetMembers (MemberTypes mt, BindingFlags bf);
 889
 890                 /// <summary>
 891                 ///   Return the container's member cache.
 892                 /// </summary>
 893                 MemberCache MemberCache {
 894                         get;
 895                 }
 896         }
 897
 898         /// <summary>
 899         ///   The MemberCache is used by dynamic and non-dynamic types to speed up
 900         ///   member lookups.  It has a member name based hash table; it maps each member
 901         ///   name to a list of CacheEntry objects.  Each CacheEntry contains a MemberInfo
 902         ///   and the BindingFlags that were initially used to get it.  The cache contains
 903         ///   all members of the current class and all inherited members.  If this cache is
 904         ///   for an interface types, it also contains all inherited members.
 905         ///
 906         ///   There are two ways to get a MemberCache:
 907         ///   * if this is a dynamic type, lookup the corresponding DeclSpace and then
 908         ///     use the DeclSpace.MemberCache property.
 909         ///   * if this not a dynamic type, call TypeHandle.GetTypeHandle() to get a
 910         ///     TypeHandle instance for the type and then use TypeHandle.MemberCache.
 911         /// </summary>
 912         public class MemberCache {
 913                 public readonly IMemberContainer Container;
 914                 protected Hashtable member_hash;
 915                 protected Hashtable method_hash;
 916                 protected Hashtable interface_hash;
 917
 918                 /// <summary>
 919                 ///   Create a new MemberCache for the given IMemberContainer `container'.
 920                 /// </summary>
 921                 public MemberCache (IMemberContainer container)
 922                 {
 923                         this.Container = container;
 924
 925                         Timer.IncrementCounter (CounterType.MemberCache);
 926                         Timer.StartTimer (TimerType.CacheInit);
 927
 928                         interface_hash = new Hashtable ();
 929
 930                         // If we have a parent class (we have a parent class unless we're
 931                         // TypeManager.object_type), we deep-copy its MemberCache here.
 932                         if (Container.Parent != null)
 933                                 member_hash = SetupCache (Container.Parent.MemberCache);
 934                         else if (Container.IsInterface)
 935                                 member_hash = SetupCacheForInterface ();
 936                         else
 937                                 member_hash = new Hashtable ();
 938
 939                         // If this is neither a dynamic type nor an interface, create a special
 940                         // method cache with all declared and inherited methods.
 941                         Type type = container.Type;
 942                         if (!(type is TypeBuilder) && !type.IsInterface) {
 943                                 method_hash = new Hashtable ();
 944                                 AddMethods (type);
 945                         }
 946
 947                         // Add all members from the current class.
 948                         AddMembers (Container);
 949
 950                         Timer.StopTimer (TimerType.CacheInit);
 951                 }
 952
 953                 /// <summary>
 954                 ///   Bootstrap this member cache by doing a deep-copy of our parent.
 955                 /// </summary>
 956                 Hashtable SetupCache (MemberCache parent)
 957                 {
 958                         Hashtable hash = new Hashtable ();
 959
 960                         IDictionaryEnumerator it = parent.member_hash.GetEnumerator ();
 961                         while (it.MoveNext ()) {
 962                                 hash [it.Key] = ((ArrayList) it.Value).Clone ();
 963                         }
 964
 965                         return hash;
 966                 }
 967
 968                 void AddInterfaces (MemberCache parent)
 969                 {
 970                         foreach (Type iface in parent.interface_hash.Keys) {
 971                                 if (!interface_hash.Contains (iface))
 972                                         interface_hash.Add (iface, true);
 973                         }
 974                 }
 975
 976                 /// <summary>
 977                 ///   Add the contents of `new_hash' to `hash'.
 978                 /// </summary>
 979                 void AddHashtable (Hashtable hash, Hashtable new_hash)
 980                 {
 981                         IDictionaryEnumerator it = new_hash.GetEnumerator ();
 982                         while (it.MoveNext ()) {
 983                                 ArrayList list = (ArrayList) hash [it.Key];
 984                                 if (list != null)
 985                                         list.AddRange ((ArrayList) it.Value);
 986                                 else
 987                                         hash [it.Key] = ((ArrayList) it.Value).Clone ();
 988                         }
 989                 }
 990
 991                 /// <summary>
 992                 ///   Bootstrap the member cache for an interface type.
 993                 ///   Type.GetMembers() won't return any inherited members for interface types,
 994                 ///   so we need to do this manually.  Interfaces also inherit from System.Object.
 995                 /// </summary>
 996                 Hashtable SetupCacheForInterface ()
 997                 {
 998                         Hashtable hash = SetupCache (TypeHandle.ObjectType.MemberCache);
 999                         Type [] ifaces = TypeManager.GetInterfaces (Container.Type);
1000
1001                         foreach (Type iface in ifaces) {
1002                                 if (interface_hash.Contains (iface))
1003                                         continue;
1004                                 interface_hash.Add (iface, true);
1005
1006                                 IMemberContainer iface_container =
1007                                         TypeManager.LookupMemberContainer (iface);
1008
1009                                 MemberCache iface_cache = iface_container.MemberCache;
1010                                 AddHashtable (hash, iface_cache.member_hash);
1011                                 AddInterfaces (iface_cache);
1012                         }
1013
1014                         return hash;
1015                 }
1016
1017                 /// <summary>
1018                 ///   Add all members from class `container' to the cache.
1019                 /// </summary>
1020                 void AddMembers (IMemberContainer container)
1021                 {
1022                         // We need to call AddMembers() with a single member type at a time
1023                         // to get the member type part of CacheEntry.EntryType right.
1024                         AddMembers (MemberTypes.Constructor, container);
1025                         AddMembers (MemberTypes.Field, container);
1026                         AddMembers (MemberTypes.Method, container);
1027                         AddMembers (MemberTypes.Property, container);
1028                         AddMembers (MemberTypes.Event, container);
1029                         // Nested types are returned by both Static and Instance searches.
1030                         AddMembers (MemberTypes.NestedType,
1031                                     BindingFlags.Static | BindingFlags.Public, container);
1032                         AddMembers (MemberTypes.NestedType,
1033                                     BindingFlags.Static | BindingFlags.NonPublic, container);
1034                 }
1035
1036                 void AddMembers (MemberTypes mt, IMemberContainer container)
1037                 {
1038                         AddMembers (mt, BindingFlags.Static | BindingFlags.Public, container);
1039                         AddMembers (mt, BindingFlags.Static | BindingFlags.NonPublic, container);
1040                         AddMembers (mt, BindingFlags.Instance | BindingFlags.Public, container);
1041                         AddMembers (mt, BindingFlags.Instance | BindingFlags.NonPublic, container);
1042                 }
1043
1044                 /// <summary>
1045                 ///   Add all members from class `container' with the requested MemberTypes and
1046                 ///   BindingFlags to the cache.  This method is called multiple times with different
1047                 ///   MemberTypes and BindingFlags.
1048                 /// </summary>
1049                 void AddMembers (MemberTypes mt, BindingFlags bf, IMemberContainer container)
1050                 {
1051                         MemberList members = container.GetMembers (mt, bf);
1052                         BindingFlags new_bf = (container == Container) ?
1053                                 bf | BindingFlags.DeclaredOnly : bf;
1054
1055                         foreach (MemberInfo member in members) {
1056                                 string name = member.Name;
1057
1058                                 // We use a name-based hash table of ArrayList's.
1059                                 ArrayList list = (ArrayList) member_hash [name];
1060                                 if (list == null) {
1061                                         list = new ArrayList ();
1062                                         member_hash.Add (name, list);
1063                                 }
1064
1065                                 // When this method is called for the current class, the list will
1066                                 // already contain all inherited members from our parent classes.
1067                                 // We cannot add new members in front of the list since this'd be an
1068                                 // expensive operation, that's why the list is sorted in reverse order
1069                                 // (ie. members from the current class are coming last).
1070                                 list.Add (new CacheEntry (container, member, mt, bf));
1071                         }
1072                 }
1073
1074                 /// <summary>
1075                 ///   Add all declared and inherited methods from class `type' to the method cache.
1076                 /// </summary>
1077                 void AddMethods (Type type)
1078                 {
1079                         AddMethods (BindingFlags.Static | BindingFlags.Public |
1080                                     BindingFlags.FlattenHierarchy, type);
1081                         AddMethods (BindingFlags.Static | BindingFlags.NonPublic |
1082                                     BindingFlags.FlattenHierarchy, type);
1083                         AddMethods (BindingFlags.Instance | BindingFlags.Public, type);
1084                         AddMethods (BindingFlags.Instance | BindingFlags.NonPublic, type);
1085                 }
1086
1087                 void AddMethods (BindingFlags bf, Type type)
1088                 {
1089                         MemberInfo [] members = type.GetMethods (bf);
1090
1091                         foreach (MethodBase member in members) {
1092                                 string name = member.Name;
1093
1094                                 // Varargs methods aren't allowed in C# code.
1095                                 if ((member.CallingConvention & CallingConventions.VarArgs) != 0)
1096                                         continue;
1097
1098                                 // We use a name-based hash table of ArrayList's.
1099                                 ArrayList list = (ArrayList) method_hash [name];
1100                                 if (list == null) {
1101                                         list = new ArrayList ();
1102                                         method_hash.Add (name, list);
1103                                 }
1104
1105                                 // Unfortunately, the elements returned by Type.GetMethods() aren't
1106                                 // sorted so we need to do this check for every member.
1107                                 BindingFlags new_bf = bf;
1108                                 if (member.DeclaringType == type)
1109                                         new_bf |= BindingFlags.DeclaredOnly;
1110
1111                                 list.Add (new CacheEntry (Container, member, MemberTypes.Method, new_bf));
1112                         }
1113                 }
1114
1115                 /// <summary>
1116                 ///   Compute and return a appropriate `EntryType' magic number for the given
1117                 ///   MemberTypes and BindingFlags.
1118                 /// </summary>
1119                 protected static EntryType GetEntryType (MemberTypes mt, BindingFlags bf)
1120                 {
1121                         EntryType type = EntryType.None;
1122
1123                         if ((mt & MemberTypes.Constructor) != 0)
1124                                 type |= EntryType.Constructor;
1125                         if ((mt & MemberTypes.Event) != 0)
1126                                 type |= EntryType.Event;
1127                         if ((mt & MemberTypes.Field) != 0)
1128                                 type |= EntryType.Field;
1129                         if ((mt & MemberTypes.Method) != 0)
1130                                 type |= EntryType.Method;
1131                         if ((mt & MemberTypes.Property) != 0)
1132                                 type |= EntryType.Property;
1133                         // Nested types are returned by static and instance searches.
1134                         if ((mt & MemberTypes.NestedType) != 0)
1135                                 type |= EntryType.NestedType | EntryType.Static | EntryType.Instance;
1136
1137                         if ((bf & BindingFlags.Instance) != 0)
1138                                 type |= EntryType.Instance;
1139                         if ((bf & BindingFlags.Static) != 0)
1140                                 type |= EntryType.Static;
1141                         if ((bf & BindingFlags.Public) != 0)
1142                                 type |= EntryType.Public;
1143                         if ((bf & BindingFlags.NonPublic) != 0)
1144                                 type |= EntryType.NonPublic;
1145                         if ((bf & BindingFlags.DeclaredOnly) != 0)
1146                                 type |= EntryType.Declared;
1147
1148                         return type;
1149                 }
1150
1151                 /// <summary>
1152                 ///   The `MemberTypes' enumeration type is a [Flags] type which means that it may
1153                 ///   denote multiple member types.  Returns true if the given flags value denotes a
1154                 ///   single member types.
1155                 /// </summary>
1156                 public static bool IsSingleMemberType (MemberTypes mt)
1157                 {
1158                         switch (mt) {
1159                         case MemberTypes.Constructor:
1160                         case MemberTypes.Event:
1161                         case MemberTypes.Field:
1162                         case MemberTypes.Method:
1163                         case MemberTypes.Property:
1164                         case MemberTypes.NestedType:
1165                                 return true;
1166
1167                         default:
1168                                 return false;
1169                         }
1170                 }
1171
1172                 /// <summary>
1173                 ///   We encode the MemberTypes and BindingFlags of each members in a "magic"
1174                 ///   number to speed up the searching process.
1175                 /// </summary>
1176                 [Flags]
1177                 protected enum EntryType {
1178                         None            = 0x000,
1179
1180                         Instance        = 0x001,
1181                         Static          = 0x002,
1182                         MaskStatic      = Instance|Static,
1183
1184                         Public          = 0x004,
1185                         NonPublic       = 0x008,
1186                         MaskProtection  = Public|NonPublic,
1187
1188                         Declared        = 0x010,
1189
1190                         Constructor     = 0x020,
1191                         Event           = 0x040,
1192                         Field           = 0x080,
1193                         Method          = 0x100,
1194                         Property        = 0x200,
1195                         NestedType      = 0x400,
1196
1197                         MaskType        = Constructor|Event|Field|Method|Property|NestedType
1198                 }
1199
1200                 protected struct CacheEntry {
1201                         public readonly IMemberContainer Container;
1202                         public readonly EntryType EntryType;
1203                         public readonly MemberInfo Member;
1204
1205                         public CacheEntry (IMemberContainer container, MemberInfo member,
1206                                            MemberTypes mt, BindingFlags bf)
1207                         {
1208                                 this.Container = container;
1209                                 this.Member = member;
1210                                 this.EntryType = GetEntryType (mt, bf);
1211                         }
1212                 }
1213
1214                 /// <summary>
1215                 ///   This is called each time we're walking up one level in the class hierarchy
1216                 ///   and checks whether we can abort the search since we've already found what
1217                 ///   we were looking for.
1218                 /// </summary>
1219                 protected bool DoneSearching (ArrayList list)
1220                 {
1221                         //
1222                         // We've found exactly one member in the current class and it's not
1223                         // a method or constructor.
1224                         //
1225                         if (list.Count == 1 && !(list [0] is MethodBase))
1226                                 return true;
1227
1228                         //
1229                         // Multiple properties: we query those just to find out the indexer
1230                         // name
1231                         //
1232                         if ((list.Count > 0) && (list [0] is PropertyInfo))
1233                                 return true;
1234
1235                         return false;
1236                 }
1237
1238                 /// <summary>
1239                 ///   Looks up members with name `name'.  If you provide an optional
1240                 ///   filter function, it'll only be called with members matching the
1241                 ///   requested member name.
1242                 ///
1243                 ///   This method will try to use the cache to do the lookup if possible.
1244                 ///
1245                 ///   Unlike other FindMembers implementations, this method will always
1246                 ///   check all inherited members - even when called on an interface type.
1247                 ///
1248                 ///   If you know that you're only looking for methods, you should use
1249                 ///   MemberTypes.Method alone since this speeds up the lookup a bit.
1250                 ///   When doing a method-only search, it'll try to use a special method
1251                 ///   cache (unless it's a dynamic type or an interface) and the returned
1252                 ///   MemberInfo's will have the correct ReflectedType for inherited methods.
1253                 ///   The lookup process will automatically restart itself in method-only
1254                 ///   search mode if it discovers that it's about to return methods.
1255                 /// </summary>
1256                 public MemberList FindMembers (MemberTypes mt, BindingFlags bf, string name,
1257                                                MemberFilter filter, object criteria)
1258                 {
1259                         bool declared_only = (bf & BindingFlags.DeclaredOnly) != 0;
1260                         bool method_search = mt == MemberTypes.Method;
1261                         // If we have a method cache and we aren't already doing a method-only search,
1262                         // then we restart a method search if the first match is a method.
1263                         bool do_method_search = !method_search && (method_hash != null);
1264
1265                         ArrayList applicable;
1266
1267                         // If this is a method-only search, we try to use the method cache if
1268                         // possible; a lookup in the method cache will return a MemberInfo with
1269                         // the correct ReflectedType for inherited methods.
1270
1271                         if (method_search && (method_hash != null))
1272                                 applicable = (ArrayList) method_hash [name];
1273                         else
1274                                 applicable = (ArrayList) member_hash [name];
1275
1276                         if (applicable == null)
1277                                 return MemberList.Empty;
1278
1279                         ArrayList list = new ArrayList ();
1280
1281                         Timer.StartTimer (TimerType.CachedLookup);
1282
1283                         EntryType type = GetEntryType (mt, bf);
1284
1285                         IMemberContainer current = Container;
1286
1287                         // `applicable' is a list of all members with the given member name `name'
1288                         // in the current class and all its parent classes.  The list is sorted in
1289                         // reverse order due to the way how the cache is initialy created (to speed
1290                         // things up, we're doing a deep-copy of our parent).
1291
1292                         for (int i = applicable.Count-1; i >= 0; i--) {
1293                                 CacheEntry entry = (CacheEntry) applicable [i];
1294
1295                                 // This happens each time we're walking one level up in the class
1296                                 // hierarchy.  If we're doing a DeclaredOnly search, we must abort
1297                                 // the first time this happens (this may already happen in the first
1298                                 // iteration of this loop if there are no members with the name we're
1299                                 // looking for in the current class).
1300                                 if (entry.Container != current) {
1301                                         if (declared_only || DoneSearching (list))
1302                                                 break;
1303
1304                                         current = entry.Container;
1305                                 }
1306
1307                                 // Is the member of the correct type ?
1308                                 if ((entry.EntryType & type & EntryType.MaskType) == 0)
1309                                         continue;
1310
1311                                 // Is the member static/non-static ?
1312                                 if ((entry.EntryType & type & EntryType.MaskStatic) == 0)
1313                                         continue;
1314
1315                                 // Apply the filter to it.
1316                                 if (filter (entry.Member, criteria)) {
1317                                         if ((entry.EntryType & EntryType.MaskType) != EntryType.Method)
1318                                                 do_method_search = false;
1319                                         list.Add (entry.Member);
1320                                 }
1321                         }
1322
1323                         Timer.StopTimer (TimerType.CachedLookup);
1324
1325                         // If we have a method cache and we aren't already doing a method-only
1326                         // search, we restart in method-only search mode if the first match is
1327                         // a method.  This ensures that we return a MemberInfo with the correct
1328                         // ReflectedType for inherited methods.
1329                         if (do_method_search && (list.Count > 0)){
1330                                 return FindMembers (MemberTypes.Method, bf, name, filter, criteria);
1331                         }
1332
1333                         return new MemberList (list);
1334                 }
1335         }
1336 }