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=2.0.5.0, 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.IsThisOrFriendAssembly (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         //
 572         // Namespace container as created by the parser
 573         //
 574         public class NamespaceEntry : IResolveContext {
 575
 576                 class UsingEntry {
 577                         readonly MemberName name;
 578                         Namespace resolved;
 579
 580                         public UsingEntry (MemberName name)
 581                         {
 582                                 this.name = name;
 583                         }
 584
 585                         public string GetSignatureForError ()
 586                         {
 587                                 return name.GetSignatureForError ();
 588                         }
 589
 590                         public Location Location {
 591                                 get { return name.Location; }
 592                         }
 593
 594                         public MemberName MemberName {
 595                                 get { return name; }
 596                         }
 597
 598                         public string Name {
 599                                 get { return GetSignatureForError (); }
 600                         }
 601
 602                         public Namespace Resolve (IResolveContext rc)
 603                         {
 604                                 if (resolved != null)
 605                                         return resolved;
 606
 607                                 FullNamedExpression fne = name.GetTypeExpression ().ResolveAsTypeStep (rc, false);
 608                                 if (fne == null)
 609                                         return null;
 610
 611                                 resolved = fne as Namespace;
 612                                 if (resolved == null) {
 613                                         Report.SymbolRelatedToPreviousError (fne.Type);
 614                                         Report.Error (138, Location,
 615                                                 "`{0}' is a type not a namespace. A using namespace directive can only be applied to namespaces",
 616                                                 GetSignatureForError ());
 617                                 }
 618                                 return resolved;
 619                         }
 620                 }
 621
 622                 class UsingAliasEntry {
 623                         public readonly string Alias;
 624                         public Location Location;
 625
 626                         public UsingAliasEntry (string alias, Location loc)
 627                         {
 628                                 this.Alias = alias;
 629                                 this.Location = loc;
 630                         }
 631
 632                         public virtual FullNamedExpression Resolve (IResolveContext rc)
 633                         {
 634                                 FullNamedExpression fne = RootNamespace.GetRootNamespace (Alias);
 635                                 if (fne == null) {
 636                                         Report.Error (430, Location,
 637                                                 "The extern alias `{0}' was not specified in -reference option",
 638                                                 Alias);
 639                                 }
 640
 641                                 return fne;
 642                         }
 643                 }
 644
 645                 class LocalUsingAliasEntry : UsingAliasEntry {
 646                         Expression resolved;
 647                         MemberName value;
 648
 649                         public LocalUsingAliasEntry (string alias, MemberName name, Location loc)
 650                                 : base (alias, loc)
 651                         {
 652                                 this.value = name;
 653                         }
 654
 655                         public override FullNamedExpression Resolve (IResolveContext rc)
 656                         {
 657                                 if (resolved != null)
 658                                         return (FullNamedExpression)resolved;
 659
 660                                 resolved = value.GetTypeExpression ().ResolveAsTypeStep (rc, false);
 661                                 if (resolved == null)
 662                                         return null;
 663
 664                                 // FIXME: This is quite wrong, the accessibility is not global
 665                                 if (resolved.Type != null) {
 666                                         TypeAttributes attr = resolved.Type.Attributes & TypeAttributes.VisibilityMask;
 667                                         if (attr == TypeAttributes.NestedPrivate || attr == TypeAttributes.NestedFamily ||
 668                                                 ((attr == TypeAttributes.NestedFamORAssem || attr == TypeAttributes.NestedAssembly) &&
 669                                                 TypeManager.LookupDeclSpace (resolved.Type) == null)) {
 670                                                 Expression.ErrorIsInaccesible (resolved.Location, resolved.GetSignatureForError ());
 671                                                 return null;
 672                                         }
 673                                 }
 674
 675                                 return (FullNamedExpression)resolved;
 676                         }
 677                 }
 678
 679                 Namespace ns;
 680                 NamespaceEntry parent, implicit_parent;
 681                 SourceFile file;
 682                 int symfile_id;
 683
 684                 // Namespace using import block
 685                 ArrayList using_aliases;
 686                 ArrayList using_clauses;
 687                 public bool DeclarationFound = false;
 688                 // End
 689
 690                 public readonly bool IsImplicit;
 691                 public readonly DeclSpace SlaveDeclSpace;
 692                 static readonly Namespace [] empty_namespaces = new Namespace [0];
 693                 Namespace [] namespace_using_table;
 694
 695                 static ArrayList entries = new ArrayList ();
 696
 697                 public static void Reset ()
 698                 {
 699                         entries = new ArrayList ();
 700                 }
 701
 702                 public NamespaceEntry (NamespaceEntry parent, SourceFile file, string name)
 703                 {
 704                         this.parent = parent;
 705                         this.file = file;
 706                         entries.Add (this);
 707
 708                         if (parent != null)
 709                                 ns = parent.NS.GetNamespace (name, true);
 710                         else if (name != null)
 711                                 ns = RootNamespace.Global.GetNamespace (name, true);
 712                         else
 713                                 ns = RootNamespace.Global;
 714                         SlaveDeclSpace = new RootDeclSpace (this);
 715                 }
 716
 717                 private NamespaceEntry (NamespaceEntry parent, SourceFile file, Namespace ns, bool slave)
 718                 {
 719                         this.parent = parent;
 720                         this.file = file;
 721                         this.IsImplicit = true;
 722                         this.ns = ns;
 723                         this.SlaveDeclSpace = slave ? new RootDeclSpace (this) : null;
 724                 }
 725
 726                 //
 727                 // According to section 16.3.1 (using-alias-directive), the namespace-or-type-name is
 728                 // resolved as if the immediately containing namespace body has no using-directives.
 729                 //
 730                 // Section 16.3.2 says that the same rule is applied when resolving the namespace-name
 731                 // in the using-namespace-directive.
 732                 //
 733                 // To implement these rules, the expressions in the using directives are resolved using
 734                 // the "doppelganger" (ghostly bodiless duplicate).
 735                 //
 736                 NamespaceEntry doppelganger;
 737                 NamespaceEntry Doppelganger {
 738                         get {
 739                                 if (!IsImplicit && doppelganger == null) {
 740                                         doppelganger = new NamespaceEntry (ImplicitParent, file, ns, true);
 741                                         doppelganger.using_aliases = using_aliases;
 742                                 }
 743                                 return doppelganger;
 744                         }
 745                 }
 746
 747                 public Namespace NS {
 748                         get { return ns; }
 749                 }
 750
 751                 public NamespaceEntry Parent {
 752                         get { return parent; }
 753                 }
 754
 755                 public NamespaceEntry ImplicitParent {
 756                         get {
 757                                 if (parent == null)
 758                                         return null;
 759                                 if (implicit_parent == null) {
 760                                         implicit_parent = (parent.NS == ns.Parent)
 761                                                 ? parent
 762                                                 : new NamespaceEntry (parent, file, ns.Parent, false);
 763                                 }
 764                                 return implicit_parent;
 765                         }
 766                 }
 767
 768                 /// <summary>
 769                 ///   Records a new namespace for resolving name references
 770                 /// </summary>
 771                 public void AddUsing (MemberName name, Location loc)
 772                 {
 773                         if (DeclarationFound){
 774                                 Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
 775                         }
 776
 777                         if (using_clauses == null) {
 778                                 using_clauses = new ArrayList ();
 779                         } else {
 780                                 foreach (UsingEntry old_entry in using_clauses) {
 781                                         if (name.Equals (old_entry.MemberName)) {
 782                                                 Report.SymbolRelatedToPreviousError (old_entry.Location, old_entry.GetSignatureForError ());
 783                                                 Report.Warning (105, 3, loc, "The using directive for `{0}' appeared previously in this namespace", name.GetSignatureForError ());
 784                                                 return;
 785                                         }
 786                                 }
 787                         }
 788
 789                         using_clauses.Add (new UsingEntry (name));
 790                 }
 791
 792                 public void AddUsingAlias (string alias, MemberName name, Location loc)
 793                 {
 794                         // TODO: This is parser bussines
 795                         if (DeclarationFound){
 796                                 Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
 797                         }
 798
 799                         if (RootContext.Version != LanguageVersion.ISO_1 && alias == "global")
 800                                 Report.Warning (440, 2, loc, "An alias named `global' will not be used when resolving 'global::';" +
 801                                         " the global namespace will be used instead");
 802
 803                         AddUsingAlias (new LocalUsingAliasEntry (alias, name, loc));
 804                 }
 805
 806                 public void AddUsingExternalAlias (string alias, Location loc)
 807                 {
 808                         // TODO: Do this in parser
 809                         bool not_first = using_clauses != null || DeclarationFound;
 810                         if (using_aliases != null && !not_first) {
 811                                 foreach (UsingAliasEntry uae in using_aliases) {
 812                                         if (uae is LocalUsingAliasEntry) {
 813                                                 not_first = true;
 814                                                 break;
 815                                         }
 816                                 }
 817                         }
 818
 819                         if (not_first)
 820                                 Report.Error (439, loc, "An extern alias declaration must precede all other elements");
 821
 822                         if (alias == "global") {
 823                                 Error_GlobalNamespaceRedefined (loc);
 824                                 return;
 825                         }
 826
 827                         AddUsingAlias (new UsingAliasEntry (alias, loc));
 828                 }
 829
 830                 void AddUsingAlias (UsingAliasEntry uae)
 831                 {
 832                         if (using_aliases == null) {
 833                                 using_aliases = new ArrayList ();
 834                         } else {
 835                                 foreach (UsingAliasEntry entry in using_aliases) {
 836                                         if (uae.Alias == entry.Alias) {
 837                                                 Report.SymbolRelatedToPreviousError (uae.Location, uae.Alias);
 838                                                 Report.Error (1537, entry.Location, "The using alias `{0}' appeared previously in this namespace",
 839                                                         entry.Alias);
 840                                                 return;
 841                                         }
 842                                 }
 843                         }
 844
 845                         using_aliases.Add (uae);
 846                 }
 847
 848                 ///
 849                 /// Does extension methods look up to find a method which matches name and extensionType.
 850                 /// Search starts from this namespace and continues hierarchically up to top level.
 851                 ///
 852                 public ExtensionMethodGroupExpr LookupExtensionMethod (Type extensionType, ClassOrStruct currentClass, string name, Location loc)
 853                 {
 854                         ArrayList candidates = null;
 855                         if (currentClass != null) {
 856                                 candidates = ns.LookupExtensionMethod (extensionType, currentClass, name, this);
 857                                 if (candidates != null)
 858                                         return new ExtensionMethodGroupExpr (candidates, this, extensionType, loc);
 859                         }
 860
 861                         foreach (Namespace n in GetUsingTable ()) {
 862                                 ArrayList a = n.LookupExtensionMethod (extensionType, null, name, this);
 863                                 if (a == null)
 864                                         continue;
 865
 866                                 if (candidates == null)
 867                                         candidates = a;
 868                                 else
 869                                         candidates.AddRange (a);
 870                         }
 871
 872                         if (candidates != null)
 873                                 return new ExtensionMethodGroupExpr (candidates, parent, extensionType, loc);
 874
 875                         if (parent == null)
 876                                 return null;
 877
 878                         return parent.LookupExtensionMethod (extensionType, currentClass, name, loc);
 879                 }
 880
 881                 public FullNamedExpression LookupNamespaceOrType (DeclSpace ds, string name, Location loc, bool ignore_cs0104)
 882                 {
 883                         // Precondition: Only simple names (no dots) will be looked up with this function.
 884                         FullNamedExpression resolved = null;
 885                         for (NamespaceEntry curr_ns = this; curr_ns != null; curr_ns = curr_ns.ImplicitParent) {
 886                                 if ((resolved = curr_ns.Lookup (ds, name, loc, ignore_cs0104)) != null)
 887                                         break;
 888                         }
 889                         return resolved;
 890                 }
 891
 892                 static void Error_AmbiguousTypeReference (Location loc, string name, FullNamedExpression t1, FullNamedExpression t2)
 893                 {
 894                         Report.SymbolRelatedToPreviousError (t1.Type);
 895                         Report.SymbolRelatedToPreviousError (t2.Type);
 896                         Report.Error (104, loc, "`{0}' is an ambiguous reference between `{1}' and `{2}'",
 897                                 name, t1.FullName, t2.FullName);
 898                 }
 899
 900                 // Looks-up a alias named @name in this and surrounding namespace declarations
 901                 public FullNamedExpression LookupAlias (string name)
 902                 {
 903                         for (NamespaceEntry n = this; n != null; n = n.ImplicitParent) {
 904                                 if (n.using_aliases == null)
 905                                         continue;
 906
 907                                 foreach (UsingAliasEntry ue in n.using_aliases) {
 908                                         if (ue.Alias == name)
 909                                                 return ue.Resolve (Doppelganger);
 910                                 }
 911                         }
 912
 913                         return null;
 914                 }
 915
 916                 private FullNamedExpression Lookup (DeclSpace ds, string name, Location loc, bool ignore_cs0104)
 917                 {
 918                         //
 919                         // Check whether it's in the namespace.
 920                         //
 921                         FullNamedExpression fne = ns.Lookup (ds, name, loc);
 922                         if (fne != null)
 923                                 return fne;
 924
 925                         //
 926                         // Check aliases.
 927                         //
 928                         if (using_aliases != null) {
 929                                 foreach (UsingAliasEntry ue in using_aliases) {
 930                                         if (ue.Alias == name)
 931                                                 return ue.Resolve (Doppelganger);
 932                                 }
 933                         }
 934
 935                         if (IsImplicit)
 936                                 return null;
 937
 938                         //
 939                         // Check using entries.
 940                         //
 941                         FullNamedExpression match = null;
 942                         foreach (Namespace using_ns in GetUsingTable ()) {
 943                                 match = using_ns.Lookup (ds, name, loc);
 944                                 if (match == null || !(match is TypeExpr))
 945                                         continue;
 946                                 if (fne != null) {
 947                                         if (!ignore_cs0104)
 948                                                 Error_AmbiguousTypeReference (loc, name, fne, match);
 949                                         return null;
 950                                 }
 951                                 fne = match;
 952                         }
 953
 954                         return fne;
 955                 }
 956
 957                 Namespace [] GetUsingTable ()
 958                 {
 959                         if (namespace_using_table != null)
 960                                 return namespace_using_table;
 961
 962                         if (using_clauses == null) {
 963                                 namespace_using_table = empty_namespaces;
 964                                 return namespace_using_table;
 965                         }
 966
 967                         ArrayList list = new ArrayList (using_clauses.Count);
 968
 969                         foreach (UsingEntry ue in using_clauses) {
 970                                 Namespace using_ns = ue.Resolve (Doppelganger);
 971                                 if (using_ns == null)
 972                                         continue;
 973
 974                                 list.Add (using_ns);
 975                         }
 976
 977                         namespace_using_table = (Namespace[])list.ToArray (typeof (Namespace));
 978                         return namespace_using_table;
 979                 }
 980
 981                 static readonly string [] empty_using_list = new string [0];
 982
 983                 public int SymbolFileID {
 984                         get {
 985                                 if (symfile_id == 0 && file.SourceFileEntry != null) {
 986                                         int parent_id = parent == null ? 0 : parent.SymbolFileID;
 987
 988                                         string [] using_list = empty_using_list;
 989                                         if (using_clauses != null) {
 990                                                 using_list = new string [using_clauses.Count];
 991                                                 for (int i = 0; i < using_clauses.Count; i++)
 992                                                         using_list [i] = ((UsingEntry) using_clauses [i]).MemberName.GetTypeName ();
 993                                         }
 994
 995                                         symfile_id = SymbolWriter.DefineNamespace (ns.Name, file.SourceFileEntry, using_list, parent_id);
 996                                 }
 997                                 return symfile_id;
 998                         }
 999                 }
1000
1001                 static void MsgtryRef (string s)
1002                 {
1003                         Console.WriteLine ("    Try using -r:" + s);
1004                 }
1005
1006                 static void MsgtryPkg (string s)
1007                 {
1008                         Console.WriteLine ("    Try using -pkg:" + s);
1009                 }
1010
1011                 public static void Error_GlobalNamespaceRedefined (Location loc)
1012                 {
1013                         Report.Error (1681, loc, "You cannot redefine the global extern alias");
1014                 }
1015
1016                 public static void Error_NamespaceNotFound (Location loc, string name)
1017                 {
1018                         Report.Error (246, loc, "The type or namespace name `{0}' could not be found. Are you missing a using directive or an assembly reference?",
1019                                 name);
1020
1021                         switch (name) {
1022                         case "Gtk": case "GtkSharp":
1023                                 MsgtryPkg ("gtk-sharp");
1024                                 break;
1025
1026                         case "Gdk": case "GdkSharp":
1027                                 MsgtryPkg ("gdk-sharp");
1028                                 break;
1029
1030                         case "Glade": case "GladeSharp":
1031                                 MsgtryPkg ("glade-sharp");
1032                                 break;
1033
1034                         case "System.Drawing":
1035                         case "System.Web.Services":
1036                         case "System.Web":
1037                         case "System.Data":
1038                         case "System.Windows.Forms":
1039                                 MsgtryRef (name);
1040                                 break;
1041                         }
1042                 }
1043
1044                 /// <summary>
1045                 ///   Used to validate that all the using clauses are correct
1046                 ///   after we are finished parsing all the files.
1047                 /// </summary>
1048                 void VerifyUsing ()
1049                 {
1050                         if (using_aliases != null) {
1051                                 foreach (UsingAliasEntry ue in using_aliases)
1052                                         ue.Resolve (Doppelganger);
1053                         }
1054
1055                         if (using_clauses != null) {
1056                                 foreach (UsingEntry ue in using_clauses)
1057                                         ue.Resolve (Doppelganger);
1058                         }
1059                 }
1060
1061                 /// <summary>
1062                 ///   Used to validate that all the using clauses are correct
1063                 ///   after we are finished parsing all the files.
1064                 /// </summary>
1065                 static public void VerifyAllUsing ()
1066                 {
1067                         foreach (NamespaceEntry entry in entries)
1068                                 entry.VerifyUsing ();
1069                 }
1070
1071                 public string GetSignatureForError ()
1072                 {
1073                         return ns.GetSignatureForError ();
1074                 }
1075
1076                 public override string ToString ()
1077                 {
1078                         return ns.ToString ();
1079                 }
1080
1081                 #region IResolveContext Members
1082
1083                 public DeclSpace DeclContainer {
1084                         get { return SlaveDeclSpace; }
1085                 }
1086
1087                 public bool IsInObsoleteScope {
1088                         get { return SlaveDeclSpace.IsInObsoleteScope; }
1089                 }
1090
1091                 public bool IsInUnsafeScope {
1092                         get { return SlaveDeclSpace.IsInUnsafeScope; }
1093                 }
1094
1095                 public DeclSpace GenericDeclContainer {
1096                         get { return SlaveDeclSpace; }
1097                 }
1098
1099                 #endregion
1100         }
1101 }