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                 public abstract bool Define (TypeContainer parent);
  47
  48                 //
  49                 // Whehter is it ok to use an unsafe pointer in this type container
  50                 //
  51                 public bool UnsafeOK (DeclSpace parent)
  52                 {
  53                         //
  54                         // First check if this MemberCore modifier flags has unsafe set
  55                         //
  56                         if ((ModFlags & Modifiers.UNSAFE) != 0)
  57                                 return true;
  58
  59                         if (parent.UnsafeContext)
  60                                 return true;
  61
  62                         Expression.UnsafeError (Location);
  63                         return false;
  64                 }
  65         }
  66
  67         /// <summary>
  68         ///   Base class for structs, classes, enumerations and interfaces.
  69         /// </summary>
  70         /// <remarks>
  71         ///   They all create new declaration spaces.  This
  72         ///   provides the common foundation for managing those name
  73         ///   spaces.
  74         /// </remarks>
  75         public abstract class DeclSpace : MemberCore {
  76                 /// <summary>
  77                 ///   this points to the actual definition that is being
  78                 ///   created with System.Reflection.Emit
  79                 /// </summary>
  80                 public TypeBuilder TypeBuilder;
  81
  82                 /// <summary>
  83                 ///   This variable tracks whether we have Closed the type
  84                 /// </summary>
  85                 public bool Created = false;
  86
  87                 //
  88                 // This is the namespace in which this typecontainer
  89                 // was declared.  We use this to resolve names.
  90                 //
  91                 public NamespaceEntry NamespaceEntry;
  92
  93                 public Hashtable Cache = new Hashtable ();
  94
  95                 public string Basename;
  96
  97                 /// <summary>
  98                 ///   defined_names is used for toplevel objects
  99                 /// </summary>
 100                 protected Hashtable defined_names;
 101
 102                 TypeContainer parent;
 103
 104                 public DeclSpace (NamespaceEntry ns, TypeContainer parent, string name, Location l)
 105                         : base (name, l)
 106                 {
 107                         NamespaceEntry = ns;
 108                         Basename = name.Substring (1 + name.LastIndexOf ('.'));
 109                         defined_names = new Hashtable ();
 110                         this.parent = parent;
 111                 }
 112
 113                 public void RecordDecl ()
 114                 {
 115                         if ((NamespaceEntry != null) && (parent == RootContext.Tree.Types))
 116                                 NamespaceEntry.DefineName (Basename, this);
 117                 }
 118
 119                 /// <summary>
 120                 ///   The result value from adding an declaration into
 121                 ///   a struct or a class
 122                 /// </summary>
 123                 public enum AdditionResult {
 124                         /// <summary>
 125                         /// The declaration has been successfully
 126                         /// added to the declation space.
 127                         /// </summary>
 128                         Success,
 129
 130                         /// <summary>
 131                         ///   The symbol has already been defined.
 132                         /// </summary>
 133                         NameExists,
 134
 135                         /// <summary>
 136                         ///   Returned if the declation being added to the
 137                         ///   name space clashes with its container name.
 138                         ///
 139                         ///   The only exceptions for this are constructors
 140                         ///   and static constructors
 141                         /// </summary>
 142                         EnclosingClash,
 143
 144                         /// <summary>
 145                         ///   Returned if a constructor was created (because syntactically
 146                         ///   it looked like a constructor) but was not (because the name
 147                         ///   of the method is not the same as the container class
 148                         /// </summary>
 149                         NotAConstructor,
 150
 151                         /// <summary>
 152                         ///   This is only used by static constructors to emit the
 153                         ///   error 111, but this error for other things really
 154                         ///   happens at another level for other functions.
 155                         /// </summary>
 156                         MethodExists,
 157
 158                         /// <summary>
 159                         ///   Some other error.
 160                         /// </summary>
 161                         Error
 162                 }
 163
 164                 /// <summary>
 165                 ///   Returns a status code based purely on the name
 166                 ///   of the member being added
 167                 /// </summary>
 168                 protected AdditionResult IsValid (string basename, string name)
 169                 {
 170                         if (basename == Basename)
 171                                 return AdditionResult.EnclosingClash;
 172
 173                         if (defined_names.Contains (name))
 174                                 return AdditionResult.NameExists;
 175
 176                         return AdditionResult.Success;
 177                 }
 178
 179                 public static int length;
 180                 public static int small;
 181
 182                 /// <summary>
 183                 ///   Introduce @name into this declaration space and
 184                 ///   associates it with the object @o.  Note that for
 185                 ///   methods this will just point to the first method. o
 186                 /// </summary>
 187                 protected void DefineName (string name, object o)
 188                 {
 189                         defined_names.Add (name, o);
 190
 191 #if DEBUGME
 192                         int p = name.LastIndexOf ('.');
 193                         int l = name.Length;
 194                         length += l;
 195                         small += l -p;
 196 #endif
 197                 }
 198
 199                 /// <summary>
 200                 ///   Returns the object associated with a given name in the declaration
 201                 ///   space.  This is the inverse operation of `DefineName'
 202                 /// </summary>
 203                 public object GetDefinition (string name)
 204                 {
 205                         return defined_names [name];
 206                 }
 207
 208                 bool in_transit = false;
 209
 210                 /// <summary>
 211                 ///   This function is used to catch recursive definitions
 212                 ///   in declarations.
 213                 /// </summary>
 214                 public bool InTransit {
 215                         get {
 216                                 return in_transit;
 217                         }
 218
 219                         set {
 220                                 in_transit = value;
 221                         }
 222                 }
 223
 224                 public TypeContainer Parent {
 225                         get {
 226                                 return parent;
 227                         }
 228                 }
 229
 230                 /// <summary>
 231                 ///   Looks up the alias for the name
 232                 /// </summary>
 233                 public string LookupAlias (string name)
 234                 {
 235                         if (NamespaceEntry != null)
 236                                 return NamespaceEntry.LookupAlias (name);
 237                         else
 238                                 return null;
 239                 }
 240
 241                 //
 242                 // root_types contains all the types.  All TopLevel types
 243                 // hence have a parent that points to `root_types', that is
 244                 // why there is a non-obvious test down here.
 245                 //
 246                 public bool IsTopLevel {
 247                         get {
 248                                 if (parent != null){
 249                                         if (parent.parent == null)
 250                                                 return true;
 251                                 }
 252                                 return false;
 253                         }
 254                 }
 255
 256                 public virtual void CloseType ()
 257                 {
 258                         if (!Created){
 259                                 try {
 260                                         TypeBuilder.CreateType ();
 261                                 } catch {
 262                                         //
 263                                         // The try/catch is needed because
 264                                         // nested enumerations fail to load when they
 265                                         // are defined.
 266                                         //
 267                                         // Even if this is the right order (enumerations
 268                                         // declared after types).
 269                                         //
 270                                         // Note that this still creates the type and
 271                                         // it is possible to save it
 272                                 }
 273                                 Created = true;
 274                         }
 275                 }
 276
 277                 /// <remarks>
 278                 ///  Should be overriten by the appropriate declaration space
 279                 /// </remarks>
 280                 public abstract TypeBuilder DefineType ();
 281
 282                 /// <summary>
 283                 ///   Define all members, but don't apply any attributes or do anything which may
 284                 ///   access not-yet-defined classes.  This method also creates the MemberCache.
 285                 /// </summary>
 286                 public abstract bool DefineMembers (TypeContainer parent);
 287
 288                 //
 289                 // Whether this is an `unsafe context'
 290                 //
 291                 public bool UnsafeContext {
 292                         get {
 293                                 if ((ModFlags & Modifiers.UNSAFE) != 0)
 294                                         return true;
 295                                 if (parent != null)
 296                                         return parent.UnsafeContext;
 297                                 return false;
 298                         }
 299                 }
 300
 301                 public static string MakeFQN (string nsn, string name)
 302                 {
 303                         if (nsn == "")
 304                                 return name;
 305                         return String.Concat (nsn, ".", name);
 306                 }
 307
 308                 EmitContext type_resolve_ec;
 309                 EmitContext GetTypeResolveEmitContext (TypeContainer parent, Location loc)
 310                 {
 311                         type_resolve_ec = new EmitContext (parent, this, loc, null, null, ModFlags, false);
 312                         type_resolve_ec.ResolvingTypeTree = true;
 313
 314                         return type_resolve_ec;
 315                 }
 316
 317                 // <summary>
 318                 //    Looks up the type, as parsed into the expression `e'
 319                 // </summary>
 320                 public Type ResolveType (Expression e, bool silent, Location loc)
 321                 {
 322                         if (type_resolve_ec == null)
 323                                 type_resolve_ec = GetTypeResolveEmitContext (parent, loc);
 324                         type_resolve_ec.loc = loc;
 325                         type_resolve_ec.ContainerType = TypeBuilder;
 326
 327                         int errors = Report.Errors;
 328                         TypeExpr d = e.ResolveAsTypeTerminal (type_resolve_ec);
 329
 330                         if (d == null || d.eclass != ExprClass.Type){
 331                                 if (!silent && errors == Report.Errors){
 332                                         Report.Error (246, loc, "Cannot find type `"+ e.ToString () +"'");
 333                                 }
 334                                 return null;
 335                         }
 336
 337                         if (!d.CheckAccessLevel (this)) {
 338                                 Report. Error (122, loc,  "`" + d.Name + "' " +
 339                                        "is inaccessible because of its protection level");
 340                                 return null;
 341                         }
 342
 343                         return d.Type;
 344                 }
 345
 346                 // <summary>
 347                 //    Resolves the expression `e' for a type, and will recursively define
 348                 //    types.
 349                 // </summary>
 350                 public TypeExpr ResolveTypeExpr (Expression e, bool silent, Location loc)
 351                 {
 352                         if (type_resolve_ec == null)
 353                                 type_resolve_ec = GetTypeResolveEmitContext (parent, loc);
 354                         type_resolve_ec.loc = loc;
 355                         type_resolve_ec.ContainerType = TypeBuilder;
 356
 357                         TypeExpr d = e.ResolveAsTypeTerminal (type_resolve_ec);
 358
 359                         if (d == null || d.eclass != ExprClass.Type){
 360                                 if (!silent){
 361                                         Report.Error (246, loc, "Cannot find type `"+ e +"'");
 362                                 }
 363                                 return null;
 364                         }
 365
 366                         return d;
 367                 }
 368
 369                 public bool CheckAccessLevel (Type check_type)
 370                 {
 371                         if (check_type == TypeBuilder)
 372                                 return true;
 373
 374                         TypeAttributes check_attr = check_type.Attributes & TypeAttributes.VisibilityMask;
 375
 376                         //
 377                         // Broken Microsoft runtime, return public for arrays, no matter what
 378                         // the accessibility is for their underlying class, and they return
 379                         // NonPublic visibility for pointers
 380                         //
 381                         if (check_type.IsArray || check_type.IsPointer)
 382                                 return CheckAccessLevel (TypeManager.GetElementType (check_type));
 383
 384                         switch (check_attr){
 385                         case TypeAttributes.Public:
 386                                 return true;
 387
 388                         case TypeAttributes.NotPublic:
 389                                 //
 390                                 // This test should probably use the declaringtype.
 391                                 //
 392                                 if (check_type.Assembly == TypeBuilder.Assembly){
 393                                         return true;
 394                                 }
 395                                 return false;
 396
 397                         case TypeAttributes.NestedPublic:
 398                                 return true;
 399
 400                         case TypeAttributes.NestedPrivate:
 401                                 string check_type_name = check_type.FullName;
 402                                 string type_name = TypeBuilder.FullName;
 403
 404                                 int cio = check_type_name.LastIndexOf ('+');
 405                                 string container = check_type_name.Substring (0, cio);
 406
 407                                 //
 408                                 // Check if the check_type is a nested class of the current type
 409                                 //
 410                                 if (check_type_name.StartsWith (type_name + "+")){
 411                                         return true;
 412                                 }
 413
 414                                 if (type_name.StartsWith (container)){
 415                                         return true;
 416                                 }
 417
 418                                 return false;
 419
 420                         case TypeAttributes.NestedFamily:
 421                                 //
 422                                 // Only accessible to methods in current type or any subtypes
 423                                 //
 424                                 return FamilyAccessible (check_type);
 425
 426                         case TypeAttributes.NestedFamANDAssem:
 427                                 return (check_type.Assembly == TypeBuilder.Assembly) &&
 428                                         FamilyAccessible (check_type);
 429
 430                         case TypeAttributes.NestedFamORAssem:
 431                                 return (check_type.Assembly == TypeBuilder.Assembly) ||
 432                                         FamilyAccessible (check_type);
 433
 434                         case TypeAttributes.NestedAssembly:
 435                                 return check_type.Assembly == TypeBuilder.Assembly;
 436                         }
 437
 438                         Console.WriteLine ("HERE: " + check_attr);
 439                         return false;
 440
 441                 }
 442
 443                 protected bool FamilyAccessible (Type check_type)
 444                 {
 445                         Type declaring = check_type.DeclaringType;
 446                         if (TypeBuilder.IsSubclassOf (declaring))
 447                                 return true;
 448
 449                         string check_type_name = check_type.FullName;
 450
 451                         int cio = check_type_name.LastIndexOf ('+');
 452                         string container = check_type_name.Substring (0, cio);
 453
 454                         //
 455                         // Check if the check_type is a nested class of the current type
 456                         //
 457                         if (check_type_name.StartsWith (container + "+"))
 458                                 return true;
 459
 460                         return false;
 461                 }
 462
 463                 // Access level of a type.
 464                 const int X = 1;
 465                 enum AccessLevel { // Each column represents `is this scope larger or equal to Blah scope'
 466                                             // Public    Assembly   Protected
 467                         Protected           = (0 << 0) | (0 << 1) | (X << 2),
 468                         Public              = (X << 0) | (X << 1) | (X << 2),
 469                         Private             = (0 << 0) | (0 << 1) | (0 << 2),
 470                         Internal            = (0 << 0) | (X << 1) | (0 << 2),
 471                         ProtectedOrInternal = (0 << 0) | (X << 1) | (X << 2),
 472                 }
 473
 474                 static AccessLevel GetAccessLevelFromModifiers (int flags)
 475                 {
 476                         if ((flags & Modifiers.INTERNAL) != 0) {
 477
 478                                 if ((flags & Modifiers.PROTECTED) != 0)
 479                                         return AccessLevel.ProtectedOrInternal;
 480                                 else
 481                                         return AccessLevel.Internal;
 482
 483                         } else if ((flags & Modifiers.PROTECTED) != 0)
 484                                 return AccessLevel.Protected;
 485
 486                         else if ((flags & Modifiers.PRIVATE) != 0)
 487                                 return AccessLevel.Private;
 488
 489                         else
 490                                 return AccessLevel.Public;
 491                 }
 492
 493                 // What is the effective access level of this?
 494                 // TODO: Cache this?
 495                 AccessLevel EffectiveAccessLevel {
 496                         get {
 497                                 AccessLevel myAccess = GetAccessLevelFromModifiers (ModFlags);
 498                                 if (!IsTopLevel && (Parent != null))
 499                                         return myAccess & Parent.EffectiveAccessLevel;
 500                                 else
 501                                         return myAccess;
 502                         }
 503                 }
 504
 505                 // Return the access level for type `t'
 506                 static AccessLevel TypeEffectiveAccessLevel (Type t)
 507                 {
 508                         if (t.IsPublic)
 509                                 return AccessLevel.Public;
 510                         if (t.IsNestedPrivate)
 511                                 return AccessLevel.Private;
 512                         if (t.IsNotPublic)
 513                                 return AccessLevel.Internal;
 514
 515                         // By now, it must be nested
 516                         AccessLevel parentLevel = TypeEffectiveAccessLevel (t.DeclaringType);
 517
 518                         if (t.IsNestedPublic)
 519                                 return parentLevel;
 520                         if (t.IsNestedAssembly)
 521                                 return parentLevel & AccessLevel.Internal;
 522                         if (t.IsNestedFamily)
 523                                 return parentLevel & AccessLevel.Protected;
 524                         if (t.IsNestedFamORAssem)
 525                                 return parentLevel & AccessLevel.ProtectedOrInternal;
 526                         if (t.IsNestedFamANDAssem)
 527                                 throw new NotImplementedException ("NestedFamANDAssem not implemented, cant make this kind of type from c# anyways");
 528
 529                         // nested private is taken care of
 530
 531                         throw new Exception ("I give up, what are you?");
 532                 }
 533
 534                 //
 535                 // This answers `is the type P, as accessible as a member M which has the
 536                 // accessability @flags which is declared as a nested member of the type T, this declspace'
 537                 //
 538                 public bool AsAccessible (Type p, int flags)
 539                 {
 540                         //
 541                         // 1) if M is private, its accessability is the same as this declspace.
 542                         // we already know that P is accessible to T before this method, so we
 543                         // may return true.
 544                         //
 545
 546                         if ((flags & Modifiers.PRIVATE) != 0)
 547                                 return true;
 548
 549                         while (p.IsArray || p.IsPointer || p.IsByRef)
 550                                 p = TypeManager.GetElementType (p);
 551
 552                         AccessLevel pAccess = TypeEffectiveAccessLevel (p);
 553                         AccessLevel mAccess = this.EffectiveAccessLevel &
 554                                 GetAccessLevelFromModifiers (flags);
 555
 556                         // for every place from which we can access M, we must
 557                         // be able to access P as well. So, we want
 558                         // For every bit in M and P, M_i -> P_1 == true
 559                         // or, ~ (M -> P) == 0 <-> ~ ( ~M | P) == 0
 560
 561                         return ~ (~ mAccess | pAccess) == 0;
 562                 }
 563
 564                 static DoubleHash dh = new DoubleHash (1000);
 565
 566                 Type LookupInterfaceOrClass (string ns, string name, out bool error)
 567                 {
 568                         DeclSpace parent;
 569                         Type t;
 570                         object r;
 571
 572                         error = false;
 573
 574                         if (dh.Lookup (ns, name, out r))
 575                                 return (Type) r;
 576                         else {
 577                                 if (ns != ""){
 578                                         if (Namespace.IsNamespace (ns)){
 579                                                 string fullname = (ns != "") ? ns + "." + name : name;
 580                                                 t = TypeManager.LookupType (fullname);
 581                                         } else
 582                                                 t = null;
 583                                 } else
 584                                         t = TypeManager.LookupType (name);
 585                         }
 586
 587                         if (t != null) {
 588                                 dh.Insert (ns, name, t);
 589                                 return t;
 590                         }
 591
 592                         //
 593                         // In case we are fed a composite name, normalize it.
 594                         //
 595                         int p = name.LastIndexOf ('.');
 596                         if (p != -1){
 597                                 ns = MakeFQN (ns, name.Substring (0, p));
 598                                 name = name.Substring (p+1);
 599                         }
 600
 601                         parent = RootContext.Tree.LookupByNamespace (ns, name);
 602                         if (parent == null) {
 603                                 dh.Insert (ns, name, null);
 604                                 return null;
 605                         }
 606
 607                         t = parent.DefineType ();
 608                         if (t == null){
 609                                 error = true;
 610                                 return null;
 611                         }
 612
 613                         dh.Insert (ns, name, t);
 614                         return t;
 615                 }
 616
 617                 public static void Error_AmbiguousTypeReference (Location loc, string name, Type t1, Type t2)
 618                 {
 619                         Report.Error (104, loc,
 620                                       String.Format ("`{0}' is an ambiguous reference ({1} or {2}) ", name,
 621                                                      t1.FullName, t2.FullName));
 622                 }
 623
 624                 /// <summary>
 625                 ///   GetType is used to resolve type names at the DeclSpace level.
 626                 ///   Use this to lookup class/struct bases, interface bases or
 627                 ///   delegate type references
 628                 /// </summary>
 629                 ///
 630                 /// <remarks>
 631                 ///   Contrast this to LookupType which is used inside method bodies to
 632                 ///   lookup types that have already been defined.  GetType is used
 633                 ///   during the tree resolution process and potentially define
 634                 ///   recursively the type
 635                 /// </remarks>
 636                 public Type FindType (Location loc, string name)
 637                 {
 638                         Type t;
 639                         bool error;
 640
 641                         //
 642                         // For the case the type we are looking for is nested within this one
 643                         // or is in any base class
 644                         //
 645                         DeclSpace containing_ds = this;
 646
 647                         while (containing_ds != null){
 648                                 Type container_type = containing_ds.TypeBuilder;
 649                                 Type current_type = container_type;
 650
 651                                 while (current_type != null && current_type != TypeManager.object_type) {
 652                                         string pre = current_type.FullName;
 653
 654                                         t = LookupInterfaceOrClass (pre, name, out error);
 655                                         if (error)
 656                                                 return null;
 657
 658                                         if ((t != null) && containing_ds.CheckAccessLevel (t))
 659                                                 return t;
 660
 661                                         current_type = current_type.BaseType;
 662                                 }
 663                                 containing_ds = containing_ds.Parent;
 664                         }
 665
 666                         //
 667                         // Attempt to lookup the class on our namespace and all it's implicit parents
 668                         //
 669                         for (NamespaceEntry ns = NamespaceEntry; ns != null; ns = ns.ImplicitParent) {
 670                                 t = LookupInterfaceOrClass (ns.FullName, name, out error);
 671                                 if (error)
 672                                         return null;
 673
 674                                 if (t != null)
 675                                         return t;
 676                         }
 677
 678                         //
 679                         // Attempt to do a direct unqualified lookup
 680                         //
 681                         t = LookupInterfaceOrClass ("", name, out error);
 682                         if (error)
 683                                 return null;
 684
 685                         if (t != null)
 686                                 return t;
 687
 688                         //
 689                         // Attempt to lookup the class on any of the `using'
 690                         // namespaces
 691                         //
 692
 693                         for (NamespaceEntry ns = NamespaceEntry; ns != null; ns = ns.Parent){
 694
 695                                 t = LookupInterfaceOrClass (ns.FullName, name, out error);
 696                                 if (error)
 697                                         return null;
 698
 699                                 if (t != null)
 700                                         return t;
 701
 702                                 //
 703                                 // Now check the using clause list
 704                                 //
 705                                 Type match = null;
 706                                 foreach (Namespace using_ns in ns.GetUsingTable ()) {
 707                                         match = LookupInterfaceOrClass (using_ns.Name, name, out error);
 708                                         if (error)
 709                                                 return null;
 710
 711                                         if (match != null){
 712                                                 if (t != null){
 713                                                         if (CheckAccessLevel (match)) {
 714                                                                 Error_AmbiguousTypeReference (loc, name, t, match);
 715                                                                 return null;
 716                                                         }
 717                                                         continue;
 718                                                 }
 719
 720                                                 t = match;
 721                                         }
 722                                 }
 723                                 if (t != null)
 724                                         return t;
 725                         }
 726
 727                         //Report.Error (246, Location, "Can not find type `"+name+"'");
 728                         return null;
 729                 }
 730
 731                 /// <remarks>
 732                 ///   This function is broken and not what you're looking for.  It should only
 733                 ///   be used while the type is still being created since it doesn't use the cache
 734                 ///   and relies on the filter doing the member name check.
 735                 /// </remarks>
 736                 public abstract MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 737                                                         MemberFilter filter, object criteria);
 738
 739                 /// <remarks>
 740                 ///   If we have a MemberCache, return it.  This property may return null if the
 741                 ///   class doesn't have a member cache or while it's still being created.
 742                 /// </remarks>
 743                 public abstract MemberCache MemberCache {
 744                         get;
 745                 }
 746         }
 747
 748         /// <summary>
 749         ///   This is a readonly list of MemberInfo's.
 750         /// </summary>
 751         public class MemberList : IList {
 752                 public readonly IList List;
 753                 int count;
 754
 755                 /// <summary>
 756                 ///   Create a new MemberList from the given IList.
 757                 /// </summary>
 758                 public MemberList (IList list)
 759                 {
 760                         if (list != null)
 761                                 this.List = list;
 762                         else
 763                                 this.List = new ArrayList ();
 764                         count = List.Count;
 765                 }
 766
 767                 /// <summary>
 768                 ///   Concatenate the ILists `first' and `second' to a new MemberList.
 769                 /// </summary>
 770                 public MemberList (IList first, IList second)
 771                 {
 772                         ArrayList list = new ArrayList ();
 773                         list.AddRange (first);
 774                         list.AddRange (second);
 775                         count = list.Count;
 776                         List = list;
 777                 }
 778
 779                 public static readonly MemberList Empty = new MemberList (new ArrayList ());
 780
 781                 /// <summary>
 782                 ///   Cast the MemberList into a MemberInfo[] array.
 783                 /// </summary>
 784                 /// <remarks>
 785                 ///   This is an expensive operation, only use it if it's really necessary.
 786                 /// </remarks>
 787                 public static explicit operator MemberInfo [] (MemberList list)
 788                 {
 789                         Timer.StartTimer (TimerType.MiscTimer);
 790                         MemberInfo [] result = new MemberInfo [list.Count];
 791                         list.CopyTo (result, 0);
 792                         Timer.StopTimer (TimerType.MiscTimer);
 793                         return result;
 794                 }
 795
 796                 // ICollection
 797
 798                 public int Count {
 799                         get {
 800                                 return count;
 801                         }
 802                 }
 803
 804                 public bool IsSynchronized {
 805                         get {
 806                                 return List.IsSynchronized;
 807                         }
 808                 }
 809
 810                 public object SyncRoot {
 811                         get {
 812                                 return List.SyncRoot;
 813                         }
 814                 }
 815
 816                 public void CopyTo (Array array, int index)
 817                 {
 818                         List.CopyTo (array, index);
 819                 }
 820
 821                 // IEnumerable
 822
 823                 public IEnumerator GetEnumerator ()
 824                 {
 825                         return List.GetEnumerator ();
 826                 }
 827
 828                 // IList
 829
 830                 public bool IsFixedSize {
 831                         get {
 832                                 return true;
 833                         }
 834                 }
 835
 836                 public bool IsReadOnly {
 837                         get {
 838                                 return true;
 839                         }
 840                 }
 841
 842                 object IList.this [int index] {
 843                         get {
 844                                 return List [index];
 845                         }
 846
 847                         set {
 848                                 throw new NotSupportedException ();
 849                         }
 850                 }
 851
 852                 // FIXME: try to find out whether we can avoid the cast in this indexer.
 853                 public MemberInfo this [int index] {
 854                         get {
 855                                 return (MemberInfo) List [index];
 856                         }
 857                 }
 858
 859                 public int Add (object value)
 860                 {
 861                         throw new NotSupportedException ();
 862                 }
 863
 864                 public void Clear ()
 865                 {
 866                         throw new NotSupportedException ();
 867                 }
 868
 869                 public bool Contains (object value)
 870                 {
 871                         return List.Contains (value);
 872                 }
 873
 874                 public int IndexOf (object value)
 875                 {
 876                         return List.IndexOf (value);
 877                 }
 878
 879                 public void Insert (int index, object value)
 880                 {
 881                         throw new NotSupportedException ();
 882                 }
 883
 884                 public void Remove (object value)
 885                 {
 886                         throw new NotSupportedException ();
 887                 }
 888
 889                 public void RemoveAt (int index)
 890                 {
 891                         throw new NotSupportedException ();
 892                 }
 893         }
 894
 895         /// <summary>
 896         ///   This interface is used to get all members of a class when creating the
 897         ///   member cache.  It must be implemented by all DeclSpace derivatives which
 898         ///   want to support the member cache and by TypeHandle to get caching of
 899         ///   non-dynamic types.
 900         /// </summary>
 901         public interface IMemberContainer {
 902                 /// <summary>
 903                 ///   The name of the IMemberContainer.  This is only used for
 904                 ///   debugging purposes.
 905                 /// </summary>
 906                 string Name {
 907                         get;
 908                 }
 909
 910                 /// <summary>
 911                 ///   The type of this IMemberContainer.
 912                 /// </summary>
 913                 Type Type {
 914                         get;
 915                 }
 916
 917                 /// <summary>
 918                 ///   Returns the IMemberContainer of the parent class or null if this
 919                 ///   is an interface or TypeManger.object_type.
 920                 ///   This is used when creating the member cache for a class to get all
 921                 ///   members from the parent class.
 922                 /// </summary>
 923                 IMemberContainer Parent {
 924                         get;
 925                 }
 926
 927                 /// <summary>
 928                 ///   Whether this is an interface.
 929                 /// </summary>
 930                 bool IsInterface {
 931                         get;
 932                 }
 933
 934                 /// <summary>
 935                 ///   Returns all members of this class with the corresponding MemberTypes
 936                 ///   and BindingFlags.
 937                 /// </summary>
 938                 /// <remarks>
 939                 ///   When implementing this method, make sure not to return any inherited
 940                 ///   members and check the MemberTypes and BindingFlags properly.
 941                 ///   Unfortunately, System.Reflection is lame and doesn't provide a way to
 942                 ///   get the BindingFlags (static/non-static,public/non-public) in the
 943                 ///   MemberInfo class, but the cache needs this information.  That's why
 944                 ///   this method is called multiple times with different BindingFlags.
 945                 /// </remarks>
 946                 MemberList GetMembers (MemberTypes mt, BindingFlags bf);
 947
 948                 /// <summary>
 949                 ///   Return the container's member cache.
 950                 /// </summary>
 951                 MemberCache MemberCache {
 952                         get;
 953                 }
 954         }
 955
 956         /// <summary>
 957         ///   The MemberCache is used by dynamic and non-dynamic types to speed up
 958         ///   member lookups.  It has a member name based hash table; it maps each member
 959         ///   name to a list of CacheEntry objects.  Each CacheEntry contains a MemberInfo
 960         ///   and the BindingFlags that were initially used to get it.  The cache contains
 961         ///   all members of the current class and all inherited members.  If this cache is
 962         ///   for an interface types, it also contains all inherited members.
 963         ///
 964         ///   There are two ways to get a MemberCache:
 965         ///   * if this is a dynamic type, lookup the corresponding DeclSpace and then
 966         ///     use the DeclSpace.MemberCache property.
 967         ///   * if this not a dynamic type, call TypeHandle.GetTypeHandle() to get a
 968         ///     TypeHandle instance for the type and then use TypeHandle.MemberCache.
 969         /// </summary>
 970         public class MemberCache {
 971                 public readonly IMemberContainer Container;
 972                 protected Hashtable member_hash;
 973                 protected Hashtable method_hash;
 974
 975                 Hashtable interface_hash;
 976
 977                 /// <summary>
 978                 ///   Create a new MemberCache for the given IMemberContainer `container'.
 979                 /// </summary>
 980                 public MemberCache (IMemberContainer container)
 981                 {
 982                         this.Container = container;
 983
 984                         Timer.IncrementCounter (CounterType.MemberCache);
 985                         Timer.StartTimer (TimerType.CacheInit);
 986
 987
 988
 989                         // If we have a parent class (we have a parent class unless we're
 990                         // TypeManager.object_type), we deep-copy its MemberCache here.
 991                         if (Container.IsInterface) {
 992                                 MemberCache parent;
 993                                 interface_hash = new Hashtable ();
 994
 995                                 if (Container.Parent != null)
 996                                         parent = Container.Parent.MemberCache;
 997                                 else
 998                                         parent = TypeHandle.ObjectType.MemberCache;
 999                                 member_hash = SetupCacheForInterface (parent);
1000                         } else if (Container.Parent != null)
1001                                 member_hash = SetupCache (Container.Parent.MemberCache);
1002                         else
1003                                 member_hash = new Hashtable ();
1004
1005                         // If this is neither a dynamic type nor an interface, create a special
1006                         // method cache with all declared and inherited methods.
1007                         Type type = container.Type;
1008                         if (!(type is TypeBuilder) && !type.IsInterface) {
1009                                 method_hash = new Hashtable ();
1010                                 AddMethods (type);
1011                         }
1012
1013                         // Add all members from the current class.
1014                         AddMembers (Container);
1015
1016                         Timer.StopTimer (TimerType.CacheInit);
1017                 }
1018
1019                 /// <summary>
1020                 ///   Bootstrap this member cache by doing a deep-copy of our parent.
1021                 /// </summary>
1022                 Hashtable SetupCache (MemberCache parent)
1023                 {
1024                         Hashtable hash = new Hashtable ();
1025
1026                         IDictionaryEnumerator it = parent.member_hash.GetEnumerator ();
1027                         while (it.MoveNext ()) {
1028                                 hash [it.Key] = ((ArrayList) it.Value).Clone ();
1029                         }
1030
1031                         return hash;
1032                 }
1033
1034
1035                 /// <summary>
1036                 ///   Add the contents of `new_hash' to `hash'.
1037                 /// </summary>
1038                 void AddHashtable (Hashtable hash, Hashtable new_hash)
1039                 {
1040                         IDictionaryEnumerator it = new_hash.GetEnumerator ();
1041                         while (it.MoveNext ()) {
1042                                 ArrayList list = (ArrayList) hash [it.Key];
1043                                 if (list != null)
1044                                         list.AddRange ((ArrayList) it.Value);
1045                                 else
1046                                         hash [it.Key] = ((ArrayList) it.Value).Clone ();
1047                         }
1048                 }
1049
1050                 /// <summary>
1051                 ///   Bootstrap the member cache for an interface type.
1052                 ///   Type.GetMembers() won't return any inherited members for interface types,
1053                 ///   so we need to do this manually.  Interfaces also inherit from System.Object.
1054                 /// </summary>
1055                 Hashtable SetupCacheForInterface (MemberCache parent)
1056                 {
1057                         Hashtable hash = SetupCache (parent);
1058                         TypeExpr [] ifaces = TypeManager.GetInterfaces (Container.Type);
1059
1060                         foreach (TypeExpr iface in ifaces) {
1061                                 Type itype = iface.Type;
1062
1063                                 if (interface_hash.Contains (itype))
1064                                         continue;
1065
1066                                 interface_hash [itype] = null;
1067
1068                                 IMemberContainer iface_container =
1069                                         TypeManager.LookupMemberContainer (itype);
1070
1071                                 MemberCache iface_cache = iface_container.MemberCache;
1072
1073                                 AddHashtable (hash, iface_cache.member_hash);
1074
1075                                 if (iface_cache.interface_hash == null)
1076                                         continue;
1077
1078                                 foreach (Type parent_contains in iface_cache.interface_hash.Keys)
1079                                         interface_hash [parent_contains] = null;
1080                         }
1081
1082                         return hash;
1083                 }
1084
1085                 /// <summary>
1086                 ///   Add all members from class `container' to the cache.
1087                 /// </summary>
1088                 void AddMembers (IMemberContainer container)
1089                 {
1090                         // We need to call AddMembers() with a single member type at a time
1091                         // to get the member type part of CacheEntry.EntryType right.
1092                         AddMembers (MemberTypes.Constructor, container);
1093                         AddMembers (MemberTypes.Field, container);
1094                         AddMembers (MemberTypes.Method, container);
1095                         AddMembers (MemberTypes.Property, container);
1096                         AddMembers (MemberTypes.Event, container);
1097                         // Nested types are returned by both Static and Instance searches.
1098                         AddMembers (MemberTypes.NestedType,
1099                                     BindingFlags.Static | BindingFlags.Public, container);
1100                         AddMembers (MemberTypes.NestedType,
1101                                     BindingFlags.Static | BindingFlags.NonPublic, container);
1102                 }
1103
1104                 void AddMembers (MemberTypes mt, IMemberContainer container)
1105                 {
1106                         AddMembers (mt, BindingFlags.Static | BindingFlags.Public, container);
1107                         AddMembers (mt, BindingFlags.Static | BindingFlags.NonPublic, container);
1108                         AddMembers (mt, BindingFlags.Instance | BindingFlags.Public, container);
1109                         AddMembers (mt, BindingFlags.Instance | BindingFlags.NonPublic, container);
1110                 }
1111
1112                 /// <summary>
1113                 ///   Add all members from class `container' with the requested MemberTypes and
1114                 ///   BindingFlags to the cache.  This method is called multiple times with different
1115                 ///   MemberTypes and BindingFlags.
1116                 /// </summary>
1117                 void AddMembers (MemberTypes mt, BindingFlags bf, IMemberContainer container)
1118                 {
1119                         MemberList members = container.GetMembers (mt, bf);
1120
1121                         foreach (MemberInfo member in members) {
1122                                 string name = member.Name;
1123
1124                                 // We use a name-based hash table of ArrayList's.
1125                                 ArrayList list = (ArrayList) member_hash [name];
1126                                 if (list == null) {
1127                                         list = new ArrayList ();
1128                                         member_hash.Add (name, list);
1129                                 }
1130
1131                                 // When this method is called for the current class, the list will
1132                                 // already contain all inherited members from our parent classes.
1133                                 // We cannot add new members in front of the list since this'd be an
1134                                 // expensive operation, that's why the list is sorted in reverse order
1135                                 // (ie. members from the current class are coming last).
1136                                 list.Add (new CacheEntry (container, member, mt, bf));
1137                         }
1138                 }
1139
1140                 /// <summary>
1141                 ///   Add all declared and inherited methods from class `type' to the method cache.
1142                 /// </summary>
1143                 void AddMethods (Type type)
1144                 {
1145                         AddMethods (BindingFlags.Static | BindingFlags.Public |
1146                                     BindingFlags.FlattenHierarchy, type);
1147                         AddMethods (BindingFlags.Static | BindingFlags.NonPublic |
1148                                     BindingFlags.FlattenHierarchy, type);
1149                         AddMethods (BindingFlags.Instance | BindingFlags.Public, type);
1150                         AddMethods (BindingFlags.Instance | BindingFlags.NonPublic, type);
1151                 }
1152
1153                 void AddMethods (BindingFlags bf, Type type)
1154                 {
1155                         MemberInfo [] members = type.GetMethods (bf);
1156
1157                         Array.Reverse (members);
1158
1159                         foreach (MethodBase member in members) {
1160                                 string name = member.Name;
1161
1162                                 // Varargs methods aren't allowed in C# code.
1163                                 if ((member.CallingConvention & CallingConventions.VarArgs) != 0)
1164                                         continue;
1165
1166                                 // We use a name-based hash table of ArrayList's.
1167                                 ArrayList list = (ArrayList) method_hash [name];
1168                                 if (list == null) {
1169                                         list = new ArrayList ();
1170                                         method_hash.Add (name, list);
1171                                 }
1172
1173                                 // Unfortunately, the elements returned by Type.GetMethods() aren't
1174                                 // sorted so we need to do this check for every member.
1175                                 BindingFlags new_bf = bf;
1176                                 if (member.DeclaringType == type)
1177                                         new_bf |= BindingFlags.DeclaredOnly;
1178
1179                                 list.Add (new CacheEntry (Container, member, MemberTypes.Method, new_bf));
1180                         }
1181
1182
1183                 }
1184
1185                 /// <summary>
1186                 ///   Compute and return a appropriate `EntryType' magic number for the given
1187                 ///   MemberTypes and BindingFlags.
1188                 /// </summary>
1189                 protected static EntryType GetEntryType (MemberTypes mt, BindingFlags bf)
1190                 {
1191                         EntryType type = EntryType.None;
1192
1193                         if ((mt & MemberTypes.Constructor) != 0)
1194                                 type |= EntryType.Constructor;
1195                         if ((mt & MemberTypes.Event) != 0)
1196                                 type |= EntryType.Event;
1197                         if ((mt & MemberTypes.Field) != 0)
1198                                 type |= EntryType.Field;
1199                         if ((mt & MemberTypes.Method) != 0)
1200                                 type |= EntryType.Method;
1201                         if ((mt & MemberTypes.Property) != 0)
1202                                 type |= EntryType.Property;
1203                         // Nested types are returned by static and instance searches.
1204                         if ((mt & MemberTypes.NestedType) != 0)
1205                                 type |= EntryType.NestedType | EntryType.Static | EntryType.Instance;
1206
1207                         if ((bf & BindingFlags.Instance) != 0)
1208                                 type |= EntryType.Instance;
1209                         if ((bf & BindingFlags.Static) != 0)
1210                                 type |= EntryType.Static;
1211                         if ((bf & BindingFlags.Public) != 0)
1212                                 type |= EntryType.Public;
1213                         if ((bf & BindingFlags.NonPublic) != 0)
1214                                 type |= EntryType.NonPublic;
1215                         if ((bf & BindingFlags.DeclaredOnly) != 0)
1216                                 type |= EntryType.Declared;
1217
1218                         return type;
1219                 }
1220
1221                 /// <summary>
1222                 ///   The `MemberTypes' enumeration type is a [Flags] type which means that it may
1223                 ///   denote multiple member types.  Returns true if the given flags value denotes a
1224                 ///   single member types.
1225                 /// </summary>
1226                 public static bool IsSingleMemberType (MemberTypes mt)
1227                 {
1228                         switch (mt) {
1229                         case MemberTypes.Constructor:
1230                         case MemberTypes.Event:
1231                         case MemberTypes.Field:
1232                         case MemberTypes.Method:
1233                         case MemberTypes.Property:
1234                         case MemberTypes.NestedType:
1235                                 return true;
1236
1237                         default:
1238                                 return false;
1239                         }
1240                 }
1241
1242                 /// <summary>
1243                 ///   We encode the MemberTypes and BindingFlags of each members in a "magic"
1244                 ///   number to speed up the searching process.
1245                 /// </summary>
1246                 [Flags]
1247                 protected enum EntryType {
1248                         None            = 0x000,
1249
1250                         Instance        = 0x001,
1251                         Static          = 0x002,
1252                         MaskStatic      = Instance|Static,
1253
1254                         Public          = 0x004,
1255                         NonPublic       = 0x008,
1256                         MaskProtection  = Public|NonPublic,
1257
1258                         Declared        = 0x010,
1259
1260                         Constructor     = 0x020,
1261                         Event           = 0x040,
1262                         Field           = 0x080,
1263                         Method          = 0x100,
1264                         Property        = 0x200,
1265                         NestedType      = 0x400,
1266
1267                         MaskType        = Constructor|Event|Field|Method|Property|NestedType
1268                 }
1269
1270                 protected struct CacheEntry {
1271                         public readonly IMemberContainer Container;
1272                         public readonly EntryType EntryType;
1273                         public readonly MemberInfo Member;
1274
1275                         public CacheEntry (IMemberContainer container, MemberInfo member,
1276                                            MemberTypes mt, BindingFlags bf)
1277                         {
1278                                 this.Container = container;
1279                                 this.Member = member;
1280                                 this.EntryType = GetEntryType (mt, bf);
1281                         }
1282                 }
1283
1284                 /// <summary>
1285                 ///   This is called each time we're walking up one level in the class hierarchy
1286                 ///   and checks whether we can abort the search since we've already found what
1287                 ///   we were looking for.
1288                 /// </summary>
1289                 protected bool DoneSearching (ArrayList list)
1290                 {
1291                         //
1292                         // We've found exactly one member in the current class and it's not
1293                         // a method or constructor.
1294                         //
1295                         if (list.Count == 1 && !(list [0] is MethodBase))
1296                                 return true;
1297
1298                         //
1299                         // Multiple properties: we query those just to find out the indexer
1300                         // name
1301                         //
1302                         if ((list.Count > 0) && (list [0] is PropertyInfo))
1303                                 return true;
1304
1305                         return false;
1306                 }
1307
1308                 /// <summary>
1309                 ///   Looks up members with name `name'.  If you provide an optional
1310                 ///   filter function, it'll only be called with members matching the
1311                 ///   requested member name.
1312                 ///
1313                 ///   This method will try to use the cache to do the lookup if possible.
1314                 ///
1315                 ///   Unlike other FindMembers implementations, this method will always
1316                 ///   check all inherited members - even when called on an interface type.
1317                 ///
1318                 ///   If you know that you're only looking for methods, you should use
1319                 ///   MemberTypes.Method alone since this speeds up the lookup a bit.
1320                 ///   When doing a method-only search, it'll try to use a special method
1321                 ///   cache (unless it's a dynamic type or an interface) and the returned
1322                 ///   MemberInfo's will have the correct ReflectedType for inherited methods.
1323                 ///   The lookup process will automatically restart itself in method-only
1324                 ///   search mode if it discovers that it's about to return methods.
1325                 /// </summary>
1326                 ArrayList global = new ArrayList ();
1327                 bool using_global = false;
1328
1329                 public MemberList FindMembers (MemberTypes mt, BindingFlags bf, string name,
1330                                                MemberFilter filter, object criteria)
1331                 {
1332                         if (using_global)
1333                                 throw new Exception ();
1334
1335                         bool declared_only = (bf & BindingFlags.DeclaredOnly) != 0;
1336                         bool method_search = mt == MemberTypes.Method;
1337                         // If we have a method cache and we aren't already doing a method-only search,
1338                         // then we restart a method search if the first match is a method.
1339                         bool do_method_search = !method_search && (method_hash != null);
1340
1341                         ArrayList applicable;
1342
1343                         // If this is a method-only search, we try to use the method cache if
1344                         // possible; a lookup in the method cache will return a MemberInfo with
1345                         // the correct ReflectedType for inherited methods.
1346
1347                         if (method_search && (method_hash != null))
1348                                 applicable = (ArrayList) method_hash [name];
1349                         else
1350                                 applicable = (ArrayList) member_hash [name];
1351
1352                         if (applicable == null)
1353                                 return MemberList.Empty;
1354
1355                         //
1356                         // 32  slots gives 53 rss/54 size
1357                         // 2/4 slots gives 55 rss
1358                         //
1359                         // Strange: from 25,000 calls, only 1,800
1360                         // are above 2.  Why does this impact it?
1361                         //
1362                         global.Clear ();
1363                         using_global = true;
1364
1365                         Timer.StartTimer (TimerType.CachedLookup);
1366
1367                         EntryType type = GetEntryType (mt, bf);
1368
1369                         IMemberContainer current = Container;
1370
1371                         // `applicable' is a list of all members with the given member name `name'
1372                         // in the current class and all its parent classes.  The list is sorted in
1373                         // reverse order due to the way how the cache is initialy created (to speed
1374                         // things up, we're doing a deep-copy of our parent).
1375
1376                         for (int i = applicable.Count-1; i >= 0; i--) {
1377                                 CacheEntry entry = (CacheEntry) applicable [i];
1378
1379                                 // This happens each time we're walking one level up in the class
1380                                 // hierarchy.  If we're doing a DeclaredOnly search, we must abort
1381                                 // the first time this happens (this may already happen in the first
1382                                 // iteration of this loop if there are no members with the name we're
1383                                 // looking for in the current class).
1384                                 if (entry.Container != current) {
1385                                         if (declared_only || DoneSearching (global))
1386                                                 break;
1387
1388                                         current = entry.Container;
1389                                 }
1390
1391                                 // Is the member of the correct type ?
1392                                 if ((entry.EntryType & type & EntryType.MaskType) == 0)
1393                                         continue;
1394
1395                                 // Is the member static/non-static ?
1396                                 if ((entry.EntryType & type & EntryType.MaskStatic) == 0)
1397                                         continue;
1398
1399                                 // Apply the filter to it.
1400                                 if (filter (entry.Member, criteria)) {
1401                                         if ((entry.EntryType & EntryType.MaskType) != EntryType.Method)
1402                                                 do_method_search = false;
1403                                         global.Add (entry.Member);
1404                                 }
1405                         }
1406
1407                         Timer.StopTimer (TimerType.CachedLookup);
1408
1409                         // If we have a method cache and we aren't already doing a method-only
1410                         // search, we restart in method-only search mode if the first match is
1411                         // a method.  This ensures that we return a MemberInfo with the correct
1412                         // ReflectedType for inherited methods.
1413                         if (do_method_search && (global.Count > 0)){
1414                                 using_global = false;
1415
1416                                 return FindMembers (MemberTypes.Method, bf, name, filter, criteria);
1417                         }
1418
1419                         using_global = false;
1420                         MemberInfo [] copy = new MemberInfo [global.Count];
1421                         global.CopyTo (copy);
1422                         return new MemberList (copy);
1423                 }
1424         }
1425 }