mcs/mcs/namespace.cs

   1 //
   2 // namespace.cs: Tracks namespaces
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //   Marek Safar (marek.safar@seznam.cz)
   7 //
   8 // (C) 2001 Ximian, Inc.
   9 //
  10 using System;
  11 using System.Collections;
  12 using System.Collections.Specialized;
  13 using System.Reflection;
  14
  15 namespace Mono.CSharp {
  16
  17         public class RootNamespace : Namespace {
  18                 static MethodInfo get_namespaces_method;
  19
  20                 string alias_name;
  21                 Assembly referenced_assembly;
  22
  23                 Hashtable all_namespaces;
  24
  25                 static Hashtable root_namespaces;
  26                 public static GlobalRootNamespace Global;
  27
  28                 static RootNamespace ()
  29                 {
  30                         get_namespaces_method = typeof (Assembly).GetMethod ("GetNamespaces", BindingFlags.Instance | BindingFlags.NonPublic);
  31
  32                         Reset ();
  33                 }
  34
  35                 public static void Reset ()
  36                 {
  37                         root_namespaces = new Hashtable ();
  38                         Global = new GlobalRootNamespace ();
  39                         root_namespaces ["global"] = Global;
  40                 }
  41
  42                 protected RootNamespace (string alias_name, Assembly assembly)
  43                         : base (null, String.Empty)
  44                 {
  45                         this.alias_name = alias_name;
  46                         referenced_assembly = assembly;
  47
  48                         all_namespaces = new Hashtable ();
  49                         all_namespaces.Add ("", this);
  50
  51                         if (referenced_assembly != null)
  52                                 ComputeNamespaces (this.referenced_assembly);
  53                 }
  54
  55                 public static void DefineRootNamespace (string name, Assembly assembly)
  56                 {
  57                         if (name == "global") {
  58                                 NamespaceEntry.Error_GlobalNamespaceRedefined (Location.Null);
  59                                 return;
  60                         }
  61                         RootNamespace retval = GetRootNamespace (name);
  62                         if (retval == null || retval.referenced_assembly != assembly)
  63                                 root_namespaces [name] = new RootNamespace (name, assembly);
  64                 }
  65
  66                 public static RootNamespace GetRootNamespace (string name)
  67                 {
  68                         return (RootNamespace) root_namespaces [name];
  69                 }
  70
  71                 public virtual Type LookupTypeReflection (string name, Location loc)
  72                 {
  73                         return GetTypeInAssembly (referenced_assembly, name);
  74                 }
  75
  76                 public void RegisterNamespace (Namespace child)
  77                 {
  78                         if (child != this)
  79                                 all_namespaces.Add (child.Name, child);
  80                 }
  81
  82                 public bool IsNamespace (string name)
  83                 {
  84                         return all_namespaces.Contains (name);
  85                 }
  86
  87                 protected void RegisterNamespace (string dotted_name)
  88                 {
  89                         if (dotted_name != null && dotted_name.Length != 0 && ! IsNamespace (dotted_name))
  90                                 GetNamespace (dotted_name, true);
  91                 }
  92
  93                 void RegisterExtensionMethodClass (Type t)
  94                 {
  95                         string n = t.Namespace;
  96                         Namespace ns = n == null ? Global : (Namespace)all_namespaces [n];
  97                         if (ns == null)
  98                                 ns = GetNamespace (n, true);
  99
 100                         ns.RegisterExternalExtensionMethodClass (t);
 101                 }
 102
 103                 protected void ComputeNamespaces (Assembly assembly)
 104                 {
 105                         // How to test whether attribute exists without loading the assembly :-(
 106 #if NET_2_1
 107                         const string SystemCore = "System.Core, Version=2.1.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089";
 108 #else
 109                         const string SystemCore = "System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089";
 110 #endif
 111                         if (TypeManager.extension_attribute_type == null &&
 112                                 assembly.FullName == SystemCore) {
 113                                 TypeManager.extension_attribute_type = assembly.GetType("System.Runtime.CompilerServices.ExtensionAttribute");
 114                         }
 115
 116                         bool contains_extension_methods = TypeManager.extension_attribute_type != null &&
 117                                         assembly.IsDefined(TypeManager.extension_attribute_type, false);
 118
 119                         if (get_namespaces_method != null && !contains_extension_methods) {
 120                                 string [] namespaces = (string []) get_namespaces_method.Invoke (assembly, null);
 121                                 foreach (string ns in namespaces)
 122                                         RegisterNamespace (ns);
 123                                 return;
 124                         }
 125
 126                         foreach (Type t in assembly.GetExportedTypes ()) {
 127                                 if ((t.Attributes & Class.StaticClassAttribute) == Class.StaticClassAttribute &&
 128                                         contains_extension_methods && t.IsDefined (TypeManager.extension_attribute_type, false))
 129                                         RegisterExtensionMethodClass (t);
 130                                 else
 131                                         RegisterNamespace (t.Namespace);
 132                         }
 133                 }
 134
 135                 protected static Type GetTypeInAssembly (Assembly assembly, string name)
 136                 {
 137                         Type t = assembly.GetType (name);
 138                         if (t == null)
 139                                 return null;
 140
 141                         if (t.IsPointer)
 142                                 throw new InternalErrorException ("Use GetPointerType() to get a pointer");
 143
 144                         TypeAttributes ta = t.Attributes & TypeAttributes.VisibilityMask;
 145                         if (ta == TypeAttributes.NestedPrivate)
 146                                 return null;
 147
 148                         if ((ta == TypeAttributes.NotPublic ||
 149                              ta == TypeAttributes.NestedAssembly ||
 150                              ta == TypeAttributes.NestedFamANDAssem) &&
 151                             !TypeManager.IsFriendAssembly (t.Assembly))
 152                                 return null;
 153
 154                         return t;
 155                 }
 156
 157                 public override string ToString ()
 158                 {
 159                         return String.Format ("RootNamespace ({0}::)", alias_name);
 160                 }
 161
 162                 public override string GetSignatureForError ()
 163                 {
 164                         return alias_name + "::";
 165                 }
 166         }
 167
 168         public class GlobalRootNamespace : RootNamespace {
 169                 Assembly [] assemblies;
 170                 Module [] modules;
 171
 172                 public GlobalRootNamespace ()
 173                         : base ("global", null)
 174                 {
 175                         assemblies = new Assembly [0];
 176                 }
 177
 178                 public Assembly [] Assemblies {
 179                         get { return assemblies; }
 180                 }
 181
 182                 public Module [] Modules {
 183                         get { return modules; }
 184                 }
 185
 186                 public void AddAssemblyReference (Assembly a)
 187                 {
 188                         foreach (Assembly assembly in assemblies) {
 189                                 if (a == assembly)
 190                                         return;
 191                         }
 192
 193                         int top = assemblies.Length;
 194                         Assembly [] n = new Assembly [top + 1];
 195                         assemblies.CopyTo (n, 0);
 196                         n [top] = a;
 197                         assemblies = n;
 198
 199                         ComputeNamespaces (a);
 200                 }
 201
 202                 public void AddModuleReference (Module m)
 203                 {
 204                         int top = modules != null ? modules.Length : 0;
 205                         Module [] n = new Module [top + 1];
 206                         if (modules != null)
 207                                 modules.CopyTo (n, 0);
 208                         n [top] = m;
 209                         modules = n;
 210
 211                         if (m == CodeGen.Module.Builder)
 212                                 return;
 213
 214                         foreach (Type t in m.GetTypes ())
 215                                 RegisterNamespace (t.Namespace);
 216                 }
 217
 218                 public override void Error_NamespaceDoesNotExist(DeclSpace ds, Location loc, string name)
 219                 {
 220                         Report.Error (400, loc, "The type or namespace name `{0}' could not be found in the global namespace (are you missing an assembly reference?)",
 221                                 name);
 222                 }
 223
 224                 public override Type LookupTypeReflection (string name, Location loc)
 225                 {
 226                         Type found_type = null;
 227
 228                         foreach (Assembly a in assemblies) {
 229                                 Type t = GetTypeInAssembly (a, name);
 230                                 if (t == null)
 231                                         continue;
 232
 233                                 if (found_type == null) {
 234                                         found_type = t;
 235                                         continue;
 236                                 }
 237
 238                                 Report.SymbolRelatedToPreviousError (found_type);
 239                                 Report.SymbolRelatedToPreviousError (t);
 240                                 Report.Error (433, loc, "The imported type `{0}' is defined multiple times", name);
 241
 242                                 return found_type;
 243                         }
 244
 245                         if (modules != null) {
 246                                 foreach (Module module in modules) {
 247                                         Type t = module.GetType (name);
 248                                         if (t == null)
 249                                                 continue;
 250
 251                                         if (found_type == null) {
 252                                                 found_type = t;
 253                                                 continue;
 254                                         }
 255
 256                                         Report.SymbolRelatedToPreviousError (found_type);
 257                                         if (loc.IsNull) {
 258                                                 DeclSpace ds = TypeManager.LookupDeclSpace (t);
 259                                                 Report.Warning (1685, 1, ds.Location, "The type `{0}' conflicts with the predefined type `{1}' and will be ignored",
 260                                                         ds.GetSignatureForError (), TypeManager.CSharpName (found_type));
 261                                                 return found_type;
 262                                         }
 263                                         Report.SymbolRelatedToPreviousError (t);
 264                                         Report.Warning (436, 2, loc, "The type `{0}' conflicts with the imported type `{1}'. Ignoring the imported type definition",
 265                                                 TypeManager.CSharpName (t), TypeManager.CSharpName (found_type));
 266                                         return t;
 267                                 }
 268                         }
 269
 270                         return found_type;
 271                 }
 272         }
 273
 274         /// <summary>
 275         ///   Keeps track of the namespaces defined in the C# code.
 276         ///
 277         ///   This is an Expression to allow it to be referenced in the
 278         ///   compiler parse/intermediate tree during name resolution.
 279         /// </summary>
 280         public class Namespace : FullNamedExpression {
 281
 282                 Namespace parent;
 283                 string fullname;
 284                 IDictionary namespaces;
 285                 IDictionary declspaces;
 286                 Hashtable cached_types;
 287                 RootNamespace root;
 288                 ArrayList external_exmethod_classes;
 289
 290                 public readonly MemberName MemberName;
 291
 292                 /// <summary>
 293                 ///   Constructor Takes the current namespace and the
 294                 ///   name.  This is bootstrapped with parent == null
 295                 ///   and name = ""
 296                 /// </summary>
 297                 public Namespace (Namespace parent, string name)
 298                 {
 299                         // Expression members.
 300                         this.eclass = ExprClass.Namespace;
 301                         this.Type = typeof (Namespace);
 302                         this.loc = Location.Null;
 303
 304                         this.parent = parent;
 305
 306                         if (parent != null)
 307                                 this.root = parent.root;
 308                         else
 309                                 this.root = this as RootNamespace;
 310
 311                         if (this.root == null)
 312                                 throw new InternalErrorException ("Root namespaces must be created using RootNamespace");
 313
 314                         string pname = parent != null ? parent.Name : "";
 315
 316                         if (pname == "")
 317                                 fullname = name;
 318                         else
 319                                 fullname = parent.Name + "." + name;
 320
 321                         if (fullname == null)
 322                                 throw new InternalErrorException ("Namespace has a null fullname");
 323
 324                         if (parent != null && parent.MemberName != MemberName.Null)
 325                                 MemberName = new MemberName (parent.MemberName, name);
 326                         else if (name.Length == 0)
 327                                 MemberName = MemberName.Null;
 328                         else
 329                                 MemberName = new MemberName (name);
 330
 331                         namespaces = new HybridDictionary ();
 332                         cached_types = new Hashtable ();
 333
 334                         root.RegisterNamespace (this);
 335                 }
 336
 337                 public override Expression DoResolve (EmitContext ec)
 338                 {
 339                         return this;
 340                 }
 341
 342                 public virtual void Error_NamespaceDoesNotExist (DeclSpace ds, Location loc, string name)
 343                 {
 344                         if (name.IndexOf ('`') > 0) {
 345                                 FullNamedExpression retval = Lookup (ds, SimpleName.RemoveGenericArity (name), loc);
 346                                 if (retval != null) {
 347                                         Error_TypeArgumentsCannotBeUsed (retval.Type, loc);
 348                                         return;
 349                                 }
 350                         } else {
 351                                 Type t = LookForAnyGenericType (name);
 352                                 if (t != null) {
 353                                         Error_InvalidNumberOfTypeArguments (t, loc);
 354                                         return;
 355                                 }
 356                         }
 357
 358                         Report.Error (234, loc, "The type or namespace name `{0}' does not exist in the namespace `{1}'. Are you missing an assembly reference?",
 359                                 name, FullName);
 360                 }
 361
 362                 public static void Error_InvalidNumberOfTypeArguments (Type t, Location loc)
 363                 {
 364                         Report.SymbolRelatedToPreviousError (t);
 365                         Report.Error (305, loc, "Using the generic type `{0}' requires `{1}' type argument(s)",
 366                                 TypeManager.CSharpName(t), TypeManager.GetNumberOfTypeArguments(t).ToString());
 367                 }
 368
 369                 public static void Error_TypeArgumentsCannotBeUsed (Type t, Location loc)
 370                 {
 371                         Report.SymbolRelatedToPreviousError (t);
 372                         Error_TypeArgumentsCannotBeUsed (loc, "type", TypeManager.CSharpName (t));
 373                 }
 374
 375                 public static void Error_TypeArgumentsCannotBeUsed (MethodBase mi, Location loc)
 376                 {
 377                         Report.SymbolRelatedToPreviousError (mi);
 378                         Error_TypeArgumentsCannotBeUsed (loc, "method", TypeManager.CSharpSignature (mi));
 379                 }
 380
 381                 static void Error_TypeArgumentsCannotBeUsed (Location loc, string type, string name)
 382                 {
 383                         Report.Error(308, loc, "The non-generic {0} `{1}' cannot be used with the type arguments",
 384                                 type, name);
 385                 }
 386
 387                 public override void Emit (EmitContext ec)
 388                 {
 389                         throw new InternalErrorException ("Expression tree referenced namespace " + fullname + " during Emit ()");
 390                 }
 391
 392                 public override string GetSignatureForError ()
 393                 {
 394                         return Name;
 395                 }
 396
 397                 public Namespace GetNamespace (string name, bool create)
 398                 {
 399                         int pos = name.IndexOf ('.');
 400
 401                         Namespace ns;
 402                         string first;
 403                         if (pos >= 0)
 404                                 first = name.Substring (0, pos);
 405                         else
 406                                 first = name;
 407
 408                         ns = (Namespace) namespaces [first];
 409                         if (ns == null) {
 410                                 if (!create)
 411                                         return null;
 412
 413                                 ns = new Namespace (this, first);
 414                                 namespaces.Add (first, ns);
 415                         }
 416
 417                         if (pos >= 0)
 418                                 ns = ns.GetNamespace (name.Substring (pos + 1), create);
 419
 420                         return ns;
 421                 }
 422
 423                 TypeExpr LookupType (string name, Location loc)
 424                 {
 425                         if (cached_types.Contains (name))
 426                                 return cached_types [name] as TypeExpr;
 427
 428                         Type t = null;
 429                         if (declspaces != null) {
 430                                 DeclSpace tdecl = declspaces [name] as DeclSpace;
 431                                 if (tdecl != null) {
 432                                         //
 433                                         // Note that this is not:
 434                                         //
 435                                         //   t = tdecl.DefineType ()
 436                                         //
 437                                         // This is to make it somewhat more useful when a DefineType
 438                                         // fails due to problems in nested types (more useful in the sense
 439                                         // of fewer misleading error messages)
 440                                         //
 441                                         tdecl.DefineType ();
 442                                         t = tdecl.TypeBuilder;
 443                                 }
 444                         }
 445                         string lookup = t != null ? t.FullName : (fullname.Length == 0 ? name : fullname + "." + name);
 446                         Type rt = root.LookupTypeReflection (lookup, loc);
 447
 448                         // HACK: loc.IsNull when the type is core type
 449                         if (t == null || (rt != null && loc.IsNull))
 450                                 t = rt;
 451
 452                         TypeExpr te = t == null ? null : new TypeExpression (t, Location.Null);
 453                         cached_types [name] = te;
 454                         return te;
 455                 }
 456
 457                 ///
 458                 /// Used for better error reporting only
 459                 ///
 460                 public Type LookForAnyGenericType (string typeName)
 461                 {
 462                         if (declspaces == null)
 463                                 return null;
 464
 465                         typeName = SimpleName.RemoveGenericArity (typeName);
 466
 467                         foreach (DictionaryEntry de in declspaces) {
 468                                 string type_item = (string) de.Key;
 469                                 int pos = type_item.LastIndexOf ('`');
 470                                 if (pos == typeName.Length && String.Compare (typeName, 0, type_item, 0, pos) == 0)
 471                                         return ((DeclSpace) de.Value).TypeBuilder;
 472                         }
 473                         return null;
 474                 }
 475
 476                 public FullNamedExpression Lookup (DeclSpace ds, string name, Location loc)
 477                 {
 478                         if (namespaces.Contains (name))
 479                                 return (Namespace) namespaces [name];
 480
 481                         return LookupType (name, loc);
 482                 }
 483
 484                 public void RegisterExternalExtensionMethodClass (Type type)
 485                 {
 486                         if (external_exmethod_classes == null)
 487                                 external_exmethod_classes = new ArrayList ();
 488
 489                         external_exmethod_classes.Add (type);
 490                 }
 491
 492                 ///
 493                 /// Looks for extension method in this namespace
 494                 ///
 495                 public ArrayList LookupExtensionMethod (Type extensionType, ClassOrStruct currentClass, string name, NamespaceEntry ns)
 496                 {
 497                         ArrayList found = null;
 498
 499                         if (declspaces != null) {
 500                                 IEnumerator e = declspaces.Values.GetEnumerator ();
 501                                 e.Reset ();
 502                                 while (e.MoveNext ()) {
 503                                         Class c = e.Current as Class;
 504                                         if (c == null)
 505                                                 continue;
 506
 507                                         if (!c.IsStaticClass)
 508                                                 continue;
 509
 510                                         ArrayList res = c.MemberCache.FindExtensionMethods (extensionType, name, c != currentClass);
 511                                         if (res == null)
 512                                                 continue;
 513
 514                                         if (found == null)
 515                                                 found = res;
 516                                         else
 517                                                 found.AddRange (res);
 518                                 }
 519                         }
 520
 521                         if (external_exmethod_classes == null)
 522                                 return found;
 523
 524                         foreach (Type t in external_exmethod_classes) {
 525                                 MemberCache m = TypeHandle.GetMemberCache (t);
 526                                 ArrayList res = m.FindExtensionMethods (extensionType, name, true);
 527                                 if (res == null)
 528                                         continue;
 529
 530                                 if (found == null)
 531                                         found = res;
 532                                 else
 533                                         found.AddRange (res);
 534                         }
 535
 536                         return found;
 537                 }
 538
 539                 public void AddDeclSpace (string name, DeclSpace ds)
 540                 {
 541                         if (declspaces == null)
 542                                 declspaces = new HybridDictionary ();
 543                         declspaces.Add (name, ds);
 544                 }
 545
 546                 /// <summary>
 547                 ///   The qualified name of the current namespace
 548                 /// </summary>
 549                 public string Name {
 550                         get { return fullname; }
 551                 }
 552
 553                 public override string FullName {
 554                         get { return fullname; }
 555                 }
 556
 557                 /// <summary>
 558                 ///   The parent of this namespace, used by the parser to "Pop"
 559                 ///   the current namespace declaration
 560                 /// </summary>
 561                 public Namespace Parent {
 562                         get { return parent; }
 563                 }
 564
 565                 public override string ToString ()
 566                 {
 567                         return String.Format ("Namespace ({0})", Name);
 568                 }
 569         }
 570
 571         public class NamespaceEntry {
 572                 Namespace ns;
 573                 NamespaceEntry parent, implicit_parent;
 574                 SourceFile file;
 575                 int symfile_id;
 576                 Hashtable aliases;
 577                 ArrayList using_clauses;
 578                 public bool DeclarationFound = false;
 579                 bool UsingFound;
 580
 581                 public readonly DeclSpace SlaveDeclSpace;
 582
 583                 ListDictionary extern_aliases;
 584
 585                 static ArrayList entries = new ArrayList ();
 586
 587                 public static void Reset ()
 588                 {
 589                         entries = new ArrayList ();
 590                 }
 591
 592                 //
 593                 // This class holds the location where a using definition is
 594                 // done, and whether it has been used by the program or not.
 595                 //
 596                 // We use this to flag using clauses for namespaces that do not
 597                 // exist.
 598                 //
 599                 public class UsingEntry : IResolveContext {
 600                         public readonly MemberName Name;
 601                         readonly NamespaceEntry NamespaceEntry;
 602                         readonly Location Location;
 603
 604                         public UsingEntry (NamespaceEntry entry, MemberName name, Location loc)
 605                         {
 606                                 Name = name;
 607                                 NamespaceEntry = entry;
 608                                 Location = loc;
 609                         }
 610
 611                         internal Namespace resolved;
 612
 613                         public Namespace Resolve ()
 614                         {
 615                                 if (resolved != null)
 616                                         return resolved;
 617
 618                                 FullNamedExpression fne = Name.GetTypeExpression ().ResolveAsTypeStep (this, false);
 619                                 if (fne == null) {
 620                                         Error_NamespaceNotFound (Location, Name.ToString ());
 621                                         return null;
 622                                 }
 623
 624                                 resolved = fne as Namespace;
 625                                 if (resolved == null) {
 626                                         Report.SymbolRelatedToPreviousError (fne.Type);
 627                                         Report.Error (138, Location,
 628                                                 "`{0}' is a type not a namespace. A using namespace directive can only be applied to namespaces", Name.ToString ());
 629                                 }
 630                                 return resolved;
 631                         }
 632
 633                         DeclSpace IResolveContext.DeclContainer {
 634                                 get { return NamespaceEntry.SlaveDeclSpace; }
 635                         }
 636
 637                         DeclSpace IResolveContext.GenericDeclContainer {
 638                                 get { return NamespaceEntry.SlaveDeclSpace; }
 639                         }
 640
 641                         bool IResolveContext.IsInObsoleteScope {
 642                                 get { return false; }
 643                         }
 644                         bool IResolveContext.IsInUnsafeScope {
 645                                 get { return false; }
 646                         }
 647                 }
 648
 649                 public abstract class AliasEntry {
 650                         public readonly string Name;
 651                         public readonly NamespaceEntry NamespaceEntry;
 652                         public readonly Location Location;
 653
 654                         protected AliasEntry (NamespaceEntry entry, string name, Location loc)
 655                         {
 656                                 Name = name;
 657                                 NamespaceEntry = entry;
 658                                 Location = loc;
 659                         }
 660
 661                         protected FullNamedExpression resolved;
 662                         bool error;
 663
 664                         public FullNamedExpression Resolve ()
 665                         {
 666                                 if (resolved != null || error)
 667                                         return resolved;
 668                                 resolved = DoResolve ();
 669                                 if (resolved == null)
 670                                         error = true;
 671                                 return resolved;
 672                         }
 673
 674                         protected abstract FullNamedExpression DoResolve ();
 675                 }
 676
 677                 public class LocalAliasEntry : AliasEntry, IResolveContext {
 678                         public readonly Expression Alias;
 679
 680                         public LocalAliasEntry (NamespaceEntry entry, string name, MemberName alias, Location loc) :
 681                                 base (entry, name, loc)
 682                         {
 683                                 Alias = alias.GetTypeExpression ();
 684                         }
 685
 686                         protected override FullNamedExpression DoResolve ()
 687                         {
 688                                 resolved = Alias.ResolveAsTypeStep (this, false);
 689                                 if (resolved == null)
 690                                         return null;
 691
 692                                 if (resolved.Type != null) {
 693                                         TypeAttributes attr = resolved.Type.Attributes & TypeAttributes.VisibilityMask;
 694                                         if (attr == TypeAttributes.NestedPrivate || attr == TypeAttributes.NestedFamily ||
 695                                                 ((attr == TypeAttributes.NestedFamORAssem || attr == TypeAttributes.NestedAssembly) &&
 696                                                 TypeManager.LookupDeclSpace (resolved.Type) == null)) {
 697                                                 Expression.ErrorIsInaccesible (Alias.Location, Alias.ToString ());
 698                                                 return null;
 699                                         }
 700                                 }
 701
 702                                 return resolved;
 703                         }
 704
 705                         DeclSpace IResolveContext.DeclContainer {
 706                                 get { return NamespaceEntry.SlaveDeclSpace; }
 707                         }
 708
 709                         DeclSpace IResolveContext.GenericDeclContainer {
 710                                 get { return NamespaceEntry.SlaveDeclSpace; }
 711                         }
 712
 713                         bool IResolveContext.IsInObsoleteScope {
 714                                 get { return false; }
 715                         }
 716                         bool IResolveContext.IsInUnsafeScope {
 717                                 get { return false; }
 718                         }
 719                 }
 720
 721                 public class ExternAliasEntry : AliasEntry {
 722                         public ExternAliasEntry (NamespaceEntry entry, string name, Location loc) :
 723                                 base (entry, name, loc)
 724                         {
 725                         }
 726
 727                         protected override FullNamedExpression DoResolve ()
 728                         {
 729                                 resolved = RootNamespace.GetRootNamespace (Name);
 730                                 if (resolved == null)
 731                                         Report.Error (430, Location, "The extern alias '" + Name +
 732                                                                         "' was not specified in a /reference option");
 733
 734                                 return resolved;
 735                         }
 736                 }
 737
 738                 public NamespaceEntry (NamespaceEntry parent, SourceFile file, string name)
 739                 {
 740                         this.parent = parent;
 741                         this.file = file;
 742                         entries.Add (this);
 743                         this.ID = entries.Count;
 744
 745                         if (parent != null)
 746                                 ns = parent.NS.GetNamespace (name, true);
 747                         else if (name != null)
 748                                 ns = RootNamespace.Global.GetNamespace (name, true);
 749                         else
 750                                 ns = RootNamespace.Global;
 751                         SlaveDeclSpace = new RootDeclSpace (this);
 752                 }
 753
 754                 private NamespaceEntry (NamespaceEntry parent, SourceFile file, Namespace ns, bool slave)
 755                 {
 756                         this.parent = parent;
 757                         this.file = file;
 758                         // no need to add self to 'entries', since we don't have any aliases or using entries.
 759                         this.ID = -1;
 760                         this.IsImplicit = true;
 761                         this.ns = ns;
 762                         this.SlaveDeclSpace = slave ? new RootDeclSpace (this) : null;
 763                 }
 764
 765                 //
 766                 // According to section 16.3.1 (using-alias-directive), the namespace-or-type-name is
 767                 // resolved as if the immediately containing namespace body has no using-directives.
 768                 //
 769                 // Section 16.3.2 says that the same rule is applied when resolving the namespace-name
 770                 // in the using-namespace-directive.
 771                 //
 772                 // To implement these rules, the expressions in the using directives are resolved using
 773                 // the "doppelganger" (ghostly bodiless duplicate).
 774                 //
 775                 NamespaceEntry doppelganger;
 776                 NamespaceEntry Doppelganger {
 777                         get {
 778                                 if (!IsImplicit && doppelganger == null)
 779                                         doppelganger = new NamespaceEntry (ImplicitParent, file, ns, true);
 780                                 return doppelganger;
 781                         }
 782                 }
 783
 784                 public readonly int ID;
 785                 public readonly bool IsImplicit;
 786
 787                 public Namespace NS {
 788                         get { return ns; }
 789                 }
 790
 791                 public NamespaceEntry Parent {
 792                         get { return parent; }
 793                 }
 794
 795                 public NamespaceEntry ImplicitParent {
 796                         get {
 797                                 if (parent == null)
 798                                         return null;
 799                                 if (implicit_parent == null) {
 800                                         implicit_parent = (parent.NS == ns.Parent)
 801                                                 ? parent
 802                                                 : new NamespaceEntry (parent, file, ns.Parent, false);
 803                                 }
 804                                 return implicit_parent;
 805                         }
 806                 }
 807
 808                 /// <summary>
 809                 ///   Records a new namespace for resolving name references
 810                 /// </summary>
 811                 public void Using (MemberName name, Location loc)
 812                 {
 813                         if (DeclarationFound){
 814                                 Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
 815                                 return;
 816                         }
 817
 818                         UsingFound = true;
 819
 820                         if (name.Equals (ns.MemberName))
 821                                 return;
 822
 823                         if (using_clauses == null)
 824                                 using_clauses = new ArrayList ();
 825
 826                         foreach (UsingEntry old_entry in using_clauses) {
 827                                 if (name.Equals (old_entry.Name)) {
 828                                         Report.Warning (105, 3, loc, "The using directive for `{0}' appeared previously in this namespace", name.GetName ());
 829                                         return;
 830                                 }
 831                         }
 832
 833                         UsingEntry ue = new UsingEntry (Doppelganger, name, loc);
 834                         using_clauses.Add (ue);
 835                 }
 836
 837                 public void UsingAlias (string name, MemberName alias, Location loc)
 838                 {
 839                         if (DeclarationFound){
 840                                 Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
 841                                 return;
 842                         }
 843
 844                         UsingFound = true;
 845
 846                         if (aliases == null)
 847                                 aliases = new Hashtable ();
 848
 849                         if (aliases.Contains (name)) {
 850                                 AliasEntry ae = (AliasEntry) aliases [name];
 851                                 Report.SymbolRelatedToPreviousError (ae.Location, ae.Name);
 852                                 Report.Error (1537, loc, "The using alias `{0}' appeared previously in this namespace", name);
 853                                 return;
 854                         }
 855
 856                         if (RootContext.Version != LanguageVersion.ISO_1 && name == "global")
 857                                 Report.Warning (440, 2, loc, "An alias named `global' will not be used when resolving 'global::';" +
 858                                         " the global namespace will be used instead");
 859
 860                         // FIXME: get correct error number.  See if the above check can be merged
 861                         if (extern_aliases != null && extern_aliases.Contains (name)) {
 862                                 AliasEntry ae = (AliasEntry) extern_aliases [name];
 863                                 Report.SymbolRelatedToPreviousError (ae.Location, ae.Name);
 864                                 Report.Error (1537, loc, "The using alias `{0}' appeared previously in this namespace", name);
 865                                 return;
 866                         }
 867
 868                         aliases [name] = new LocalAliasEntry (Doppelganger, name, alias, loc);
 869                 }
 870
 871                 public void UsingExternalAlias (string name, Location loc)
 872                 {
 873                         if (UsingFound || DeclarationFound) {
 874                                 Report.Error (439, loc, "An extern alias declaration must precede all other elements");
 875                                 return;
 876                         }
 877
 878                         // Share the extern_aliases field with the Doppelganger
 879                         if (extern_aliases == null) {
 880                                 extern_aliases = new ListDictionary ();
 881                                 Doppelganger.extern_aliases = extern_aliases;
 882                         }
 883
 884                         if (extern_aliases.Contains (name)) {
 885                                 AliasEntry ae = (AliasEntry) extern_aliases [name];
 886                                 Report.SymbolRelatedToPreviousError (ae.Location, ae.Name);
 887                                 Report.Error (1537, loc, "The using alias `{0}' appeared previously in this namespace", name);
 888                                 return;
 889                         }
 890
 891                         if (name == "global") {
 892                                 Error_GlobalNamespaceRedefined (loc);
 893                                 return;
 894                         }
 895
 896                         // Register the alias in aliases and extern_aliases, since we need both of them
 897                         // to keep things simple (different resolution scenarios)
 898                         ExternAliasEntry alias = new ExternAliasEntry (Doppelganger, name, loc);
 899                         extern_aliases [name] = alias;
 900                 }
 901
 902                 ///
 903                 /// Does extension methods look up to find a method which matches name and extensionType.
 904                 /// Search starts from this namespace and continues hierarchically up to top level.
 905                 ///
 906                 public ExtensionMethodGroupExpr LookupExtensionMethod (Type extensionType, ClassOrStruct currentClass, string name)
 907                 {
 908                         ArrayList candidates = null;
 909                         if (currentClass != null) {
 910                                 candidates = ns.LookupExtensionMethod (extensionType, currentClass, name, this);
 911                                 if (candidates != null)
 912                                         return new ExtensionMethodGroupExpr (candidates, this, extensionType, Location.Null);
 913                         }
 914
 915                         foreach (Namespace n in GetUsingTable ()) {
 916                                 ArrayList a = n.LookupExtensionMethod (extensionType, null, name, this);
 917                                 if (a == null)
 918                                         continue;
 919
 920                                 if (candidates == null)
 921                                         candidates = a;
 922                                 else
 923                                         candidates.AddRange (a);
 924                         }
 925
 926                         if (candidates != null)
 927                                 return new ExtensionMethodGroupExpr (candidates, parent, extensionType, Location.Null);
 928
 929                         if (parent == null)
 930                                 return null;
 931
 932                         return parent.LookupExtensionMethod (extensionType, currentClass, name);
 933                 }
 934
 935                 public FullNamedExpression LookupNamespaceOrType (DeclSpace ds, string name, Location loc, bool ignore_cs0104)
 936                 {
 937                         // Precondition: Only simple names (no dots) will be looked up with this function.
 938                         FullNamedExpression resolved = null;
 939                         for (NamespaceEntry curr_ns = this; curr_ns != null; curr_ns = curr_ns.ImplicitParent) {
 940                                 if ((resolved = curr_ns.Lookup (ds, name, loc, ignore_cs0104)) != null)
 941                                         break;
 942                         }
 943                         return resolved;
 944                 }
 945
 946                 static void Error_AmbiguousTypeReference (Location loc, string name, FullNamedExpression t1, FullNamedExpression t2)
 947                 {
 948                         Report.SymbolRelatedToPreviousError (t1.Type);
 949                         Report.SymbolRelatedToPreviousError (t2.Type);
 950                         Report.Error (104, loc, "`{0}' is an ambiguous reference between `{1}' and `{2}'",
 951                                 name, t1.FullName, t2.FullName);
 952                 }
 953
 954                 // Looks-up a alias named @name in this and surrounding namespace declarations
 955                 public FullNamedExpression LookupAlias (string name)
 956                 {
 957                         AliasEntry entry = null;
 958                         for (NamespaceEntry n = this; n != null; n = n.ImplicitParent) {
 959                                 if (n.extern_aliases != null && (entry = n.extern_aliases [name] as AliasEntry) != null)
 960                                         break;
 961                                 if (n.aliases != null && (entry = n.aliases [name] as AliasEntry) != null)
 962                                         break;
 963                         }
 964                         return entry == null ? null : entry.Resolve ();
 965                 }
 966
 967                 private FullNamedExpression Lookup (DeclSpace ds, string name, Location loc, bool ignore_cs0104)
 968                 {
 969                         //
 970                         // Check whether it's in the namespace.
 971                         //
 972                         FullNamedExpression fne = ns.Lookup (ds, name, loc);
 973                         if (fne != null)
 974                                 return fne;
 975
 976                         if (extern_aliases != null) {
 977                                 AliasEntry entry = extern_aliases [name] as AliasEntry;
 978                                 if (entry != null)
 979                                         return entry.Resolve ();
 980                         }
 981
 982                         if (IsImplicit)
 983                                 return null;
 984
 985                         //
 986                         // Check aliases.
 987                         //
 988                         if (aliases != null) {
 989                                 AliasEntry entry = aliases [name] as AliasEntry;
 990                                 if (entry != null)
 991                                         return entry.Resolve ();
 992                         }
 993
 994                         //
 995                         // Check using entries.
 996                         //
 997                         FullNamedExpression match = null;
 998                         foreach (Namespace using_ns in GetUsingTable ()) {
 999                                 match = using_ns.Lookup (ds, name, loc);
1000                                 if (match == null || !(match is TypeExpr))
1001                                         continue;
1002                                 if (fne != null) {
1003                                         if (!ignore_cs0104)
1004                                                 Error_AmbiguousTypeReference (loc, name, fne, match);
1005                                         return null;
1006                                 }
1007                                 fne = match;
1008                         }
1009
1010                         return fne;
1011                 }
1012
1013                 // Our cached computation.
1014                 static readonly Namespace [] empty_namespaces = new Namespace [0];
1015                 Namespace [] namespace_using_table;
1016                 Namespace [] GetUsingTable ()
1017                 {
1018                         if (namespace_using_table != null)
1019                                 return namespace_using_table;
1020
1021                         if (using_clauses == null) {
1022                                 namespace_using_table = empty_namespaces;
1023                                 return namespace_using_table;
1024                         }
1025
1026                         ArrayList list = new ArrayList (using_clauses.Count);
1027
1028                         foreach (UsingEntry ue in using_clauses) {
1029                                 Namespace using_ns = ue.Resolve ();
1030                                 if (using_ns == null)
1031                                         continue;
1032
1033                                 list.Add (using_ns);
1034                         }
1035
1036                         namespace_using_table = new Namespace [list.Count];
1037                         list.CopyTo (namespace_using_table, 0);
1038                         return namespace_using_table;
1039                 }
1040
1041                 static readonly string [] empty_using_list = new string [0];
1042
1043                 public int SymbolFileID {
1044                         get {
1045                                 if (symfile_id == 0 && file.SourceFileEntry != null) {
1046                                         int parent_id = parent == null ? 0 : parent.SymbolFileID;
1047
1048                                         string [] using_list = empty_using_list;
1049                                         if (using_clauses != null) {
1050                                                 using_list = new string [using_clauses.Count];
1051                                                 for (int i = 0; i < using_clauses.Count; i++)
1052                                                         using_list [i] = ((UsingEntry) using_clauses [i]).Name.ToString ();
1053                                         }
1054
1055                                         symfile_id = CodeGen.SymbolWriter.DefineNamespace (ns.Name, file.SourceFileEntry, using_list, parent_id);
1056                                 }
1057                                 return symfile_id;
1058                         }
1059                 }
1060
1061                 static void MsgtryRef (string s)
1062                 {
1063                         Console.WriteLine ("    Try using -r:" + s);
1064                 }
1065
1066                 static void MsgtryPkg (string s)
1067                 {
1068                         Console.WriteLine ("    Try using -pkg:" + s);
1069                 }
1070
1071                 public static void Error_GlobalNamespaceRedefined (Location loc)
1072                 {
1073                         Report.Error (1681, loc, "You cannot redefine the global extern alias");
1074                 }
1075
1076                 public static void Error_NamespaceNotFound (Location loc, string name)
1077                 {
1078                         Report.Error (246, loc, "The type or namespace name `{0}' could not be found. Are you missing a using directive or an assembly reference?",
1079                                 name);
1080
1081                         switch (name) {
1082                         case "Gtk": case "GtkSharp":
1083                                 MsgtryPkg ("gtk-sharp");
1084                                 break;
1085
1086                         case "Gdk": case "GdkSharp":
1087                                 MsgtryPkg ("gdk-sharp");
1088                                 break;
1089
1090                         case "Glade": case "GladeSharp":
1091                                 MsgtryPkg ("glade-sharp");
1092                                 break;
1093
1094                         case "System.Drawing":
1095                         case "System.Web.Services":
1096                         case "System.Web":
1097                         case "System.Data":
1098                         case "System.Windows.Forms":
1099                                 MsgtryRef (name);
1100                                 break;
1101                         }
1102                 }
1103
1104                 /// <summary>
1105                 ///   Used to validate that all the using clauses are correct
1106                 ///   after we are finished parsing all the files.
1107                 /// </summary>
1108                 void VerifyUsing ()
1109                 {
1110                         if (extern_aliases != null) {
1111                                 foreach (DictionaryEntry de in extern_aliases)
1112                                         ((AliasEntry) de.Value).Resolve ();
1113                         }
1114
1115                         if (using_clauses != null) {
1116                                 foreach (UsingEntry ue in using_clauses)
1117                                         ue.Resolve ();
1118                         }
1119
1120                         if (aliases != null) {
1121                                 foreach (DictionaryEntry de in aliases)
1122                                         ((AliasEntry) de.Value).Resolve ();
1123                         }
1124                 }
1125
1126                 /// <summary>
1127                 ///   Used to validate that all the using clauses are correct
1128                 ///   after we are finished parsing all the files.
1129                 /// </summary>
1130                 static public void VerifyAllUsing ()
1131                 {
1132                         foreach (NamespaceEntry entry in entries)
1133                                 entry.VerifyUsing ();
1134                 }
1135
1136                 public string GetSignatureForError ()
1137                 {
1138                         return ns.GetSignatureForError ();
1139                 }
1140
1141                 public override string ToString ()
1142                 {
1143                         return ns.ToString ();
1144                 }
1145         }
1146 }