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                         const string SystemCore = "System.Core, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089";
 107                         if (TypeManager.extension_attribute_type == null &&
 108                                 assembly.FullName == SystemCore) {
 109                                 TypeManager.extension_attribute_type = assembly.GetType("System.Runtime.CompilerServices.ExtensionAttribute");
 110                         }
 111
 112                         bool contains_extension_methods = TypeManager.extension_attribute_type != null &&
 113                                         assembly.IsDefined(TypeManager.extension_attribute_type, false);
 114
 115                         if (get_namespaces_method != null && !contains_extension_methods) {
 116                                 string [] namespaces = (string []) get_namespaces_method.Invoke (assembly, null);
 117                                 foreach (string ns in namespaces)
 118                                         RegisterNamespace (ns);
 119                                 return;
 120                         }
 121
 122                         foreach (Type t in assembly.GetExportedTypes ()) {
 123                                 if ((t.Attributes & Class.StaticClassAttribute) == Class.StaticClassAttribute &&
 124                                         contains_extension_methods && t.IsDefined (TypeManager.extension_attribute_type, false))
 125                                         RegisterExtensionMethodClass (t);
 126                                 else
 127                                         RegisterNamespace (t.Namespace);
 128                         }
 129                 }
 130
 131                 protected static Type GetTypeInAssembly (Assembly assembly, string name)
 132                 {
 133                         Type t = assembly.GetType (name);
 134                         if (t == null)
 135                                 return null;
 136
 137                         if (t.IsPointer)
 138                                 throw new InternalErrorException ("Use GetPointerType() to get a pointer");
 139
 140                         TypeAttributes ta = t.Attributes & TypeAttributes.VisibilityMask;
 141                         if (ta == TypeAttributes.NestedPrivate)
 142                                 return null;
 143
 144                         if ((ta == TypeAttributes.NotPublic ||
 145                              ta == TypeAttributes.NestedAssembly ||
 146                              ta == TypeAttributes.NestedFamANDAssem) &&
 147                             !TypeManager.IsFriendAssembly (t.Assembly))
 148                                 return null;
 149
 150                         return t;
 151                 }
 152
 153                 public override string ToString ()
 154                 {
 155                         return String.Format ("RootNamespace ({0}::)", alias_name);
 156                 }
 157
 158                 public override string GetSignatureForError ()
 159                 {
 160                         return alias_name + "::";
 161                 }
 162         }
 163
 164         public class GlobalRootNamespace : RootNamespace {
 165                 Assembly [] assemblies;
 166                 Module [] modules;
 167
 168                 public GlobalRootNamespace ()
 169                         : base ("global", null)
 170                 {
 171                         assemblies = new Assembly [0];
 172                 }
 173
 174                 public Assembly [] Assemblies {
 175                         get { return assemblies; }
 176                 }
 177
 178                 public Module [] Modules {
 179                         get { return modules; }
 180                 }
 181
 182                 public void AddAssemblyReference (Assembly a)
 183                 {
 184                         foreach (Assembly assembly in assemblies) {
 185                                 if (a == assembly)
 186                                         return;
 187                         }
 188
 189                         int top = assemblies.Length;
 190                         Assembly [] n = new Assembly [top + 1];
 191                         assemblies.CopyTo (n, 0);
 192                         n [top] = a;
 193                         assemblies = n;
 194
 195                         ComputeNamespaces (a);
 196                 }
 197
 198                 public void AddModuleReference (Module m)
 199                 {
 200                         int top = modules != null ? modules.Length : 0;
 201                         Module [] n = new Module [top + 1];
 202                         if (modules != null)
 203                                 modules.CopyTo (n, 0);
 204                         n [top] = m;
 205                         modules = n;
 206
 207                         if (m == CodeGen.Module.Builder)
 208                                 return;
 209
 210                         foreach (Type t in m.GetTypes ())
 211                                 RegisterNamespace (t.Namespace);
 212                 }
 213
 214                 public override void Error_NamespaceDoesNotExist(DeclSpace ds, Location loc, string name)
 215                 {
 216                         Report.Error (400, loc, "The type or namespace name `{0}' could not be found in the global namespace (are you missing an assembly reference?)",
 217                                 name);
 218                 }
 219
 220                 public override Type LookupTypeReflection (string name, Location loc)
 221                 {
 222                         Type found_type = null;
 223
 224                         foreach (Assembly a in assemblies) {
 225                                 Type t = GetTypeInAssembly (a, name);
 226                                 if (t == null)
 227                                         continue;
 228
 229                                 if (found_type == null) {
 230                                         found_type = t;
 231                                         continue;
 232                                 }
 233
 234                                 Report.SymbolRelatedToPreviousError (found_type);
 235                                 Report.SymbolRelatedToPreviousError (t);
 236                                 Report.Error (433, loc, "The imported type `{0}' is defined multiple times", name);
 237
 238                                 return found_type;
 239                         }
 240
 241                         if (modules != null) {
 242                                 foreach (Module module in modules) {
 243                                         Type t = module.GetType (name);
 244                                         if (t == null)
 245                                                 continue;
 246
 247                                         if (found_type == null) {
 248                                                 found_type = t;
 249                                                 continue;
 250                                         }
 251
 252                                         Report.SymbolRelatedToPreviousError (found_type);
 253                                         if (loc.IsNull) {
 254                                                 DeclSpace ds = TypeManager.LookupDeclSpace (t);
 255                                                 Report.Warning (1685, 1, ds.Location, "The type `{0}' conflicts with the predefined type `{1}' and will be ignored",
 256                                                         ds.GetSignatureForError (), TypeManager.CSharpName (found_type));
 257                                                 return found_type;
 258                                         }
 259                                         Report.SymbolRelatedToPreviousError (t);
 260                                         Report.Warning (436, 2, loc, "The type `{0}' conflicts with the imported type `{1}'. Ignoring the imported type definition",
 261                                                 TypeManager.CSharpName (t), TypeManager.CSharpName (found_type));
 262                                         return t;
 263                                 }
 264                         }
 265
 266                         return found_type;
 267                 }
 268         }
 269
 270         /// <summary>
 271         ///   Keeps track of the namespaces defined in the C# code.
 272         ///
 273         ///   This is an Expression to allow it to be referenced in the
 274         ///   compiler parse/intermediate tree during name resolution.
 275         /// </summary>
 276         public class Namespace : FullNamedExpression {
 277
 278                 Namespace parent;
 279                 string fullname;
 280                 IDictionary namespaces;
 281                 IDictionary declspaces;
 282                 Hashtable cached_types;
 283                 RootNamespace root;
 284                 ArrayList external_exmethod_classes;
 285
 286                 public readonly MemberName MemberName;
 287
 288                 /// <summary>
 289                 ///   Constructor Takes the current namespace and the
 290                 ///   name.  This is bootstrapped with parent == null
 291                 ///   and name = ""
 292                 /// </summary>
 293                 public Namespace (Namespace parent, string name)
 294                 {
 295                         // Expression members.
 296                         this.eclass = ExprClass.Namespace;
 297                         this.Type = typeof (Namespace);
 298                         this.loc = Location.Null;
 299
 300                         this.parent = parent;
 301
 302                         if (parent != null)
 303                                 this.root = parent.root;
 304                         else
 305                                 this.root = this as RootNamespace;
 306
 307                         if (this.root == null)
 308                                 throw new InternalErrorException ("Root namespaces must be created using RootNamespace");
 309
 310                         string pname = parent != null ? parent.Name : "";
 311
 312                         if (pname == "")
 313                                 fullname = name;
 314                         else
 315                                 fullname = parent.Name + "." + name;
 316
 317                         if (fullname == null)
 318                                 throw new InternalErrorException ("Namespace has a null fullname");
 319
 320                         if (parent != null && parent.MemberName != MemberName.Null)
 321                                 MemberName = new MemberName (parent.MemberName, name);
 322                         else if (name.Length == 0)
 323                                 MemberName = MemberName.Null;
 324                         else
 325                                 MemberName = new MemberName (name);
 326
 327                         namespaces = new HybridDictionary ();
 328                         cached_types = new Hashtable ();
 329
 330                         root.RegisterNamespace (this);
 331                 }
 332
 333                 public override Expression DoResolve (EmitContext ec)
 334                 {
 335                         return this;
 336                 }
 337
 338                 public virtual void Error_NamespaceDoesNotExist (DeclSpace ds, Location loc, string name)
 339                 {
 340                         if (name.IndexOf ('`') > 0) {
 341                                 FullNamedExpression retval = Lookup (ds, SimpleName.RemoveGenericArity (name), loc);
 342                                 if (retval != null) {
 343                                         Error_TypeArgumentsCannotBeUsed (retval.Type, loc, "type");
 344                                         return;
 345                                 }
 346                         } else {
 347                                 Type t = LookForAnyGenericType (name);
 348                                 if (t != null) {
 349                                         Error_InvalidNumberOfTypeArguments (t, loc);
 350                                         return;
 351                                 }
 352                         }
 353
 354                         Report.Error (234, loc, "The type or namespace name `{0}' does not exist in the namespace `{1}'. Are you missing an assembly reference?",
 355                                 name, FullName);
 356                 }
 357
 358                 public static void Error_InvalidNumberOfTypeArguments (Type t, Location loc)
 359                 {
 360                         Report.SymbolRelatedToPreviousError (t);
 361                         Report.Error (305, loc, "Using the generic type `{0}' requires `{1}' type argument(s)",
 362                                 TypeManager.CSharpName(t), TypeManager.GetNumberOfTypeArguments(t).ToString());
 363                 }
 364
 365                 public static void Error_TypeArgumentsCannotBeUsed(Type t, Location loc, string symbol)
 366                 {
 367                         Report.SymbolRelatedToPreviousError(t);
 368                         Report.Error(308, loc, "The non-generic {0} `{1}' cannot be used with the type arguments",
 369                                 symbol, TypeManager.CSharpName(t));
 370                 }
 371
 372                 public override void Emit (EmitContext ec)
 373                 {
 374                         throw new InternalErrorException ("Expression tree referenced namespace " + fullname + " during Emit ()");
 375                 }
 376
 377                 public override string GetSignatureForError ()
 378                 {
 379                         return Name;
 380                 }
 381
 382                 public Namespace GetNamespace (string name, bool create)
 383                 {
 384                         int pos = name.IndexOf ('.');
 385
 386                         Namespace ns;
 387                         string first;
 388                         if (pos >= 0)
 389                                 first = name.Substring (0, pos);
 390                         else
 391                                 first = name;
 392
 393                         ns = (Namespace) namespaces [first];
 394                         if (ns == null) {
 395                                 if (!create)
 396                                         return null;
 397
 398                                 ns = new Namespace (this, first);
 399                                 namespaces.Add (first, ns);
 400                         }
 401
 402                         if (pos >= 0)
 403                                 ns = ns.GetNamespace (name.Substring (pos + 1), create);
 404
 405                         return ns;
 406                 }
 407
 408                 TypeExpr LookupType (string name, Location loc)
 409                 {
 410                         if (cached_types.Contains (name))
 411                                 return cached_types [name] as TypeExpr;
 412
 413                         Type t = null;
 414                         if (declspaces != null) {
 415                                 DeclSpace tdecl = declspaces [name] as DeclSpace;
 416                                 if (tdecl != null) {
 417                                         //
 418                                         // Note that this is not:
 419                                         //
 420                                         //   t = tdecl.DefineType ()
 421                                         //
 422                                         // This is to make it somewhat more useful when a DefineType
 423                                         // fails due to problems in nested types (more useful in the sense
 424                                         // of fewer misleading error messages)
 425                                         //
 426                                         tdecl.DefineType ();
 427                                         t = tdecl.TypeBuilder;
 428                                 }
 429                         }
 430                         string lookup = t != null ? t.FullName : (fullname.Length == 0 ? name : fullname + "." + name);
 431                         Type rt = root.LookupTypeReflection (lookup, loc);
 432
 433                         // HACK: loc.IsNull when the type is core type
 434                         if (t == null || (rt != null && loc.IsNull))
 435                                 t = rt;
 436
 437                         TypeExpr te = t == null ? null : new TypeExpression (t, Location.Null);
 438                         cached_types [name] = te;
 439                         return te;
 440                 }
 441
 442                 ///
 443                 /// Used for better error reporting only
 444                 ///
 445                 public Type LookForAnyGenericType (string typeName)
 446                 {
 447                         if (declspaces == null)
 448                                 return null;
 449
 450                         typeName = SimpleName.RemoveGenericArity (typeName);
 451
 452                         foreach (DictionaryEntry de in declspaces) {
 453                                 string type_item = (string) de.Key;
 454                                 int pos = type_item.LastIndexOf ('`');
 455                                 if (pos == typeName.Length && String.Compare (typeName, 0, type_item, 0, pos) == 0)
 456                                         return ((DeclSpace) de.Value).TypeBuilder;
 457                         }
 458                         return null;
 459                 }
 460
 461                 public FullNamedExpression Lookup (DeclSpace ds, string name, Location loc)
 462                 {
 463                         if (namespaces.Contains (name))
 464                                 return (Namespace) namespaces [name];
 465
 466                         return LookupType (name, loc);
 467                 }
 468
 469                 public void RegisterExternalExtensionMethodClass (Type type)
 470                 {
 471                         if (external_exmethod_classes == null)
 472                                 external_exmethod_classes = new ArrayList ();
 473
 474                         external_exmethod_classes.Add (type);
 475                 }
 476
 477                 ///
 478                 /// Looks for extension method in this namespace
 479                 ///
 480                 public ArrayList LookupExtensionMethod (Type extensionType, ClassOrStruct currentClass, string name, NamespaceEntry ns)
 481                 {
 482                         ArrayList found = null;
 483
 484                         if (declspaces != null) {
 485                                 IEnumerator e = declspaces.Values.GetEnumerator ();
 486                                 e.Reset ();
 487                                 while (e.MoveNext ()) {
 488                                         Class c = e.Current as Class;
 489                                         if (c == null)
 490                                                 continue;
 491
 492                                         if (!c.IsStaticClass)
 493                                                 continue;
 494
 495                                         ArrayList res = c.MemberCache.FindExtensionMethods (extensionType, name, c != currentClass);
 496                                         if (res == null)
 497                                                 continue;
 498
 499                                         if (found == null)
 500                                                 found = res;
 501                                         else
 502                                                 found.AddRange (res);
 503                                 }
 504                         }
 505
 506                         if (external_exmethod_classes == null)
 507                                 return found;
 508
 509                         foreach (Type t in external_exmethod_classes) {
 510                                 MemberCache m = TypeHandle.GetMemberCache (t);
 511                                 ArrayList res = m.FindExtensionMethods (extensionType, name, true);
 512                                 if (res == null)
 513                                         continue;
 514
 515                                 if (found == null)
 516                                         found = res;
 517                                 else
 518                                         found.AddRange (res);
 519                         }
 520
 521                         return found;
 522                 }
 523
 524                 public void AddDeclSpace (string name, DeclSpace ds)
 525                 {
 526                         if (declspaces == null)
 527                                 declspaces = new HybridDictionary ();
 528                         declspaces.Add (name, ds);
 529                 }
 530
 531                 /// <summary>
 532                 ///   The qualified name of the current namespace
 533                 /// </summary>
 534                 public string Name {
 535                         get { return fullname; }
 536                 }
 537
 538                 public override string FullName {
 539                         get { return fullname; }
 540                 }
 541
 542                 /// <summary>
 543                 ///   The parent of this namespace, used by the parser to "Pop"
 544                 ///   the current namespace declaration
 545                 /// </summary>
 546                 public Namespace Parent {
 547                         get { return parent; }
 548                 }
 549
 550                 public override string ToString ()
 551                 {
 552                         return String.Format ("Namespace ({0})", Name);
 553                 }
 554         }
 555
 556         public class NamespaceEntry {
 557                 Namespace ns;
 558                 NamespaceEntry parent, implicit_parent;
 559                 SourceFile file;
 560                 int symfile_id;
 561                 Hashtable aliases;
 562                 ArrayList using_clauses;
 563                 public bool DeclarationFound = false;
 564                 bool UsingFound;
 565
 566                 public readonly DeclSpace SlaveDeclSpace;
 567
 568                 ListDictionary extern_aliases;
 569
 570                 static ArrayList entries = new ArrayList ();
 571
 572                 public static void Reset ()
 573                 {
 574                         entries = new ArrayList ();
 575                 }
 576
 577                 //
 578                 // This class holds the location where a using definition is
 579                 // done, and whether it has been used by the program or not.
 580                 //
 581                 // We use this to flag using clauses for namespaces that do not
 582                 // exist.
 583                 //
 584                 public class UsingEntry : IResolveContext {
 585                         public readonly MemberName Name;
 586                         readonly NamespaceEntry NamespaceEntry;
 587                         readonly Location Location;
 588
 589                         public UsingEntry (NamespaceEntry entry, MemberName name, Location loc)
 590                         {
 591                                 Name = name;
 592                                 NamespaceEntry = entry;
 593                                 Location = loc;
 594                         }
 595
 596                         internal Namespace resolved;
 597
 598                         public Namespace Resolve ()
 599                         {
 600                                 if (resolved != null)
 601                                         return resolved;
 602
 603                                 FullNamedExpression fne = Name.GetTypeExpression ().ResolveAsTypeStep (this, false);
 604                                 if (fne == null) {
 605                                         Error_NamespaceNotFound (Location, Name.ToString ());
 606                                         return null;
 607                                 }
 608
 609                                 resolved = fne as Namespace;
 610                                 if (resolved == null) {
 611                                         Report.SymbolRelatedToPreviousError (fne.Type);
 612                                         Report.Error (138, Location,
 613                                                 "`{0}' is a type not a namespace. A using namespace directive can only be applied to namespaces", Name.ToString ());
 614                                 }
 615                                 return resolved;
 616                         }
 617
 618                         DeclSpace IResolveContext.DeclContainer {
 619                                 get { return NamespaceEntry.SlaveDeclSpace; }
 620                         }
 621
 622                         DeclSpace IResolveContext.GenericDeclContainer {
 623                                 get { return NamespaceEntry.SlaveDeclSpace; }
 624                         }
 625
 626                         bool IResolveContext.IsInObsoleteScope {
 627                                 get { return false; }
 628                         }
 629                         bool IResolveContext.IsInUnsafeScope {
 630                                 get { return false; }
 631                         }
 632                 }
 633
 634                 public abstract class AliasEntry {
 635                         public readonly string Name;
 636                         public readonly NamespaceEntry NamespaceEntry;
 637                         public readonly Location Location;
 638
 639                         protected AliasEntry (NamespaceEntry entry, string name, Location loc)
 640                         {
 641                                 Name = name;
 642                                 NamespaceEntry = entry;
 643                                 Location = loc;
 644                         }
 645
 646                         protected FullNamedExpression resolved;
 647                         bool error;
 648
 649                         public FullNamedExpression Resolve ()
 650                         {
 651                                 if (resolved != null || error)
 652                                         return resolved;
 653                                 resolved = DoResolve ();
 654                                 if (resolved == null)
 655                                         error = true;
 656                                 return resolved;
 657                         }
 658
 659                         protected abstract FullNamedExpression DoResolve ();
 660                 }
 661
 662                 public class LocalAliasEntry : AliasEntry, IResolveContext {
 663                         public readonly Expression Alias;
 664
 665                         public LocalAliasEntry (NamespaceEntry entry, string name, MemberName alias, Location loc) :
 666                                 base (entry, name, loc)
 667                         {
 668                                 Alias = alias.GetTypeExpression ();
 669                         }
 670
 671                         protected override FullNamedExpression DoResolve ()
 672                         {
 673                                 resolved = Alias.ResolveAsTypeStep (this, false);
 674                                 if (resolved == null)
 675                                         return null;
 676
 677                                 if (resolved.Type != null) {
 678                                         TypeAttributes attr = resolved.Type.Attributes & TypeAttributes.VisibilityMask;
 679                                         if (attr == TypeAttributes.NestedPrivate || attr == TypeAttributes.NestedFamily ||
 680                                                 ((attr == TypeAttributes.NestedFamORAssem || attr == TypeAttributes.NestedAssembly) &&
 681                                                 TypeManager.LookupDeclSpace (resolved.Type) == null)) {
 682                                                 Expression.ErrorIsInaccesible (Alias.Location, Alias.ToString ());
 683                                                 return null;
 684                                         }
 685                                 }
 686
 687                                 return resolved;
 688                         }
 689
 690                         DeclSpace IResolveContext.DeclContainer {
 691                                 get { return NamespaceEntry.SlaveDeclSpace; }
 692                         }
 693
 694                         DeclSpace IResolveContext.GenericDeclContainer {
 695                                 get { return NamespaceEntry.SlaveDeclSpace; }
 696                         }
 697
 698                         bool IResolveContext.IsInObsoleteScope {
 699                                 get { return false; }
 700                         }
 701                         bool IResolveContext.IsInUnsafeScope {
 702                                 get { return false; }
 703                         }
 704                 }
 705
 706                 public class ExternAliasEntry : AliasEntry {
 707                         public ExternAliasEntry (NamespaceEntry entry, string name, Location loc) :
 708                                 base (entry, name, loc)
 709                         {
 710                         }
 711
 712                         protected override FullNamedExpression DoResolve ()
 713                         {
 714                                 resolved = RootNamespace.GetRootNamespace (Name);
 715                                 if (resolved == null)
 716                                         Report.Error (430, Location, "The extern alias '" + Name +
 717                                                                         "' was not specified in a /reference option");
 718
 719                                 return resolved;
 720                         }
 721                 }
 722
 723                 public NamespaceEntry (NamespaceEntry parent, SourceFile file, string name)
 724                 {
 725                         this.parent = parent;
 726                         this.file = file;
 727                         entries.Add (this);
 728                         this.ID = entries.Count;
 729
 730                         if (parent != null)
 731                                 ns = parent.NS.GetNamespace (name, true);
 732                         else if (name != null)
 733                                 ns = RootNamespace.Global.GetNamespace (name, true);
 734                         else
 735                                 ns = RootNamespace.Global;
 736                         SlaveDeclSpace = new RootDeclSpace (this);
 737                 }
 738
 739                 private NamespaceEntry (NamespaceEntry parent, SourceFile file, Namespace ns, bool slave)
 740                 {
 741                         this.parent = parent;
 742                         this.file = file;
 743                         // no need to add self to 'entries', since we don't have any aliases or using entries.
 744                         this.ID = -1;
 745                         this.IsImplicit = true;
 746                         this.ns = ns;
 747                         this.SlaveDeclSpace = slave ? new RootDeclSpace (this) : null;
 748                 }
 749
 750                 //
 751                 // According to section 16.3.1 (using-alias-directive), the namespace-or-type-name is
 752                 // resolved as if the immediately containing namespace body has no using-directives.
 753                 //
 754                 // Section 16.3.2 says that the same rule is applied when resolving the namespace-name
 755                 // in the using-namespace-directive.
 756                 //
 757                 // To implement these rules, the expressions in the using directives are resolved using
 758                 // the "doppelganger" (ghostly bodiless duplicate).
 759                 //
 760                 NamespaceEntry doppelganger;
 761                 NamespaceEntry Doppelganger {
 762                         get {
 763                                 if (!IsImplicit && doppelganger == null)
 764                                         doppelganger = new NamespaceEntry (ImplicitParent, file, ns, true);
 765                                 return doppelganger;
 766                         }
 767                 }
 768
 769                 public readonly int ID;
 770                 public readonly bool IsImplicit;
 771
 772                 public Namespace NS {
 773                         get { return ns; }
 774                 }
 775
 776                 public NamespaceEntry Parent {
 777                         get { return parent; }
 778                 }
 779
 780                 public NamespaceEntry ImplicitParent {
 781                         get {
 782                                 if (parent == null)
 783                                         return null;
 784                                 if (implicit_parent == null) {
 785                                         implicit_parent = (parent.NS == ns.Parent)
 786                                                 ? parent
 787                                                 : new NamespaceEntry (parent, file, ns.Parent, false);
 788                                 }
 789                                 return implicit_parent;
 790                         }
 791                 }
 792
 793                 /// <summary>
 794                 ///   Records a new namespace for resolving name references
 795                 /// </summary>
 796                 public void Using (MemberName name, Location loc)
 797                 {
 798                         if (DeclarationFound){
 799                                 Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
 800                                 return;
 801                         }
 802
 803                         UsingFound = true;
 804
 805                         if (name.Equals (ns.MemberName))
 806                                 return;
 807
 808                         if (using_clauses == null)
 809                                 using_clauses = new ArrayList ();
 810
 811                         foreach (UsingEntry old_entry in using_clauses) {
 812                                 if (name.Equals (old_entry.Name)) {
 813                                         Report.Warning (105, 3, loc, "The using directive for `{0}' appeared previously in this namespace", name.GetName ());
 814                                         return;
 815                                 }
 816                         }
 817
 818                         UsingEntry ue = new UsingEntry (Doppelganger, name, loc);
 819                         using_clauses.Add (ue);
 820                 }
 821
 822                 public void UsingAlias (string name, MemberName alias, Location loc)
 823                 {
 824                         if (DeclarationFound){
 825                                 Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
 826                                 return;
 827                         }
 828
 829                         UsingFound = true;
 830
 831                         if (aliases == null)
 832                                 aliases = new Hashtable ();
 833
 834                         if (aliases.Contains (name)) {
 835                                 AliasEntry ae = (AliasEntry) aliases [name];
 836                                 Report.SymbolRelatedToPreviousError (ae.Location, ae.Name);
 837                                 Report.Error (1537, loc, "The using alias `{0}' appeared previously in this namespace", name);
 838                                 return;
 839                         }
 840
 841                         if (RootContext.Version == LanguageVersion.Default &&
 842                             name == "global")
 843                                 Report.Warning (440, 2, loc, "An alias named `global' will not be used when resolving 'global::';" +
 844                                         " the global namespace will be used instead");
 845
 846                         // FIXME: get correct error number.  See if the above check can be merged
 847                         if (extern_aliases != null && extern_aliases.Contains (name)) {
 848                                 AliasEntry ae = (AliasEntry) extern_aliases [name];
 849                                 Report.SymbolRelatedToPreviousError (ae.Location, ae.Name);
 850                                 Report.Error (1537, loc, "The using alias `{0}' appeared previously in this namespace", name);
 851                                 return;
 852                         }
 853
 854                         aliases [name] = new LocalAliasEntry (Doppelganger, name, alias, loc);
 855                 }
 856
 857                 public void UsingExternalAlias (string name, Location loc)
 858                 {
 859                         if (UsingFound || DeclarationFound) {
 860                                 Report.Error (439, loc, "An extern alias declaration must precede all other elements");
 861                                 return;
 862                         }
 863
 864                         // Share the extern_aliases field with the Doppelganger
 865                         if (extern_aliases == null) {
 866                                 extern_aliases = new ListDictionary ();
 867                                 Doppelganger.extern_aliases = extern_aliases;
 868                         }
 869
 870                         if (extern_aliases.Contains (name)) {
 871                                 AliasEntry ae = (AliasEntry) extern_aliases [name];
 872                                 Report.SymbolRelatedToPreviousError (ae.Location, ae.Name);
 873                                 Report.Error (1537, loc, "The using alias `{0}' appeared previously in this namespace", name);
 874                                 return;
 875                         }
 876
 877                         if (name == "global") {
 878                                 Error_GlobalNamespaceRedefined (loc);
 879                                 return;
 880                         }
 881
 882                         // Register the alias in aliases and extern_aliases, since we need both of them
 883                         // to keep things simple (different resolution scenarios)
 884                         ExternAliasEntry alias = new ExternAliasEntry (Doppelganger, name, loc);
 885                         extern_aliases [name] = alias;
 886                 }
 887
 888                 ///
 889                 /// Does extension methods look up to find a method which matches name and extensionType.
 890                 /// Search starts from this namespace and continues hierarchically up to top level.
 891                 ///
 892                 public ExtensionMethodGroupExpr LookupExtensionMethod (Type extensionType, ClassOrStruct currentClass, string name)
 893                 {
 894                         ArrayList candidates = null;
 895                         if (currentClass != null) {
 896                                 candidates = ns.LookupExtensionMethod (extensionType, currentClass, name, this);
 897                                 if (candidates != null)
 898                                         return new ExtensionMethodGroupExpr (candidates, this, extensionType, Location.Null);
 899                         }
 900
 901                         foreach (Namespace n in GetUsingTable ()) {
 902                                 ArrayList a = n.LookupExtensionMethod (extensionType, null, name, this);
 903                                 if (a == null)
 904                                         continue;
 905
 906                                 if (candidates == null)
 907                                         candidates = a;
 908                                 else
 909                                         candidates.AddRange (a);
 910                         }
 911
 912                         if (candidates != null)
 913                                 return new ExtensionMethodGroupExpr (candidates, parent, extensionType, Location.Null);
 914
 915                         if (parent == null)
 916                                 return null;
 917
 918                         return parent.LookupExtensionMethod (extensionType, currentClass, name);
 919                 }
 920
 921                 public FullNamedExpression LookupNamespaceOrType (DeclSpace ds, string name, Location loc, bool ignore_cs0104)
 922                 {
 923                         // Precondition: Only simple names (no dots) will be looked up with this function.
 924                         FullNamedExpression resolved = null;
 925                         for (NamespaceEntry curr_ns = this; curr_ns != null; curr_ns = curr_ns.ImplicitParent) {
 926                                 if ((resolved = curr_ns.Lookup (ds, name, loc, ignore_cs0104)) != null)
 927                                         break;
 928                         }
 929                         return resolved;
 930                 }
 931
 932                 static void Error_AmbiguousTypeReference (Location loc, string name, FullNamedExpression t1, FullNamedExpression t2)
 933                 {
 934                         Report.SymbolRelatedToPreviousError (t1.Type);
 935                         Report.SymbolRelatedToPreviousError (t2.Type);
 936                         Report.Error (104, loc, "`{0}' is an ambiguous reference between `{1}' and `{2}'",
 937                                 name, t1.FullName, t2.FullName);
 938                 }
 939
 940                 // Looks-up a alias named @name in this and surrounding namespace declarations
 941                 public FullNamedExpression LookupAlias (string name)
 942                 {
 943                         AliasEntry entry = null;
 944                         for (NamespaceEntry n = this; n != null; n = n.ImplicitParent) {
 945                                 if (n.extern_aliases != null && (entry = n.extern_aliases [name] as AliasEntry) != null)
 946                                         break;
 947                                 if (n.aliases != null && (entry = n.aliases [name] as AliasEntry) != null)
 948                                         break;
 949                         }
 950                         return entry == null ? null : entry.Resolve ();
 951                 }
 952
 953                 private FullNamedExpression Lookup (DeclSpace ds, string name, Location loc, bool ignore_cs0104)
 954                 {
 955                         //
 956                         // Check whether it's in the namespace.
 957                         //
 958                         FullNamedExpression fne = ns.Lookup (ds, name, loc);
 959                         if (fne != null)
 960                                 return fne;
 961
 962                         if (extern_aliases != null) {
 963                                 AliasEntry entry = extern_aliases [name] as AliasEntry;
 964                                 if (entry != null)
 965                                         return entry.Resolve ();
 966                         }
 967
 968                         if (IsImplicit)
 969                                 return null;
 970
 971                         //
 972                         // Check aliases.
 973                         //
 974                         if (aliases != null) {
 975                                 AliasEntry entry = aliases [name] as AliasEntry;
 976                                 if (entry != null)
 977                                         return entry.Resolve ();
 978                         }
 979
 980                         //
 981                         // Check using entries.
 982                         //
 983                         FullNamedExpression match = null;
 984                         foreach (Namespace using_ns in GetUsingTable ()) {
 985                                 match = using_ns.Lookup (ds, name, loc);
 986                                 if (match == null || !(match is TypeExpr))
 987                                         continue;
 988                                 if (fne != null) {
 989                                         if (!ignore_cs0104)
 990                                                 Error_AmbiguousTypeReference (loc, name, fne, match);
 991                                         return null;
 992                                 }
 993                                 fne = match;
 994                         }
 995
 996                         return fne;
 997                 }
 998
 999                 // Our cached computation.
1000                 static readonly Namespace [] empty_namespaces = new Namespace [0];
1001                 Namespace [] namespace_using_table;
1002                 Namespace [] GetUsingTable ()
1003                 {
1004                         if (namespace_using_table != null)
1005                                 return namespace_using_table;
1006
1007                         if (using_clauses == null) {
1008                                 namespace_using_table = empty_namespaces;
1009                                 return namespace_using_table;
1010                         }
1011
1012                         ArrayList list = new ArrayList (using_clauses.Count);
1013
1014                         foreach (UsingEntry ue in using_clauses) {
1015                                 Namespace using_ns = ue.Resolve ();
1016                                 if (using_ns == null)
1017                                         continue;
1018
1019                                 list.Add (using_ns);
1020                         }
1021
1022                         namespace_using_table = new Namespace [list.Count];
1023                         list.CopyTo (namespace_using_table, 0);
1024                         return namespace_using_table;
1025                 }
1026
1027                 static readonly string [] empty_using_list = new string [0];
1028
1029                 public int SymbolFileID {
1030                         get {
1031                                 if (symfile_id == 0 && file.SourceFileEntry != null) {
1032                                         int parent_id = parent == null ? 0 : parent.SymbolFileID;
1033
1034                                         string [] using_list = empty_using_list;
1035                                         if (using_clauses != null) {
1036                                                 using_list = new string [using_clauses.Count];
1037                                                 for (int i = 0; i < using_clauses.Count; i++)
1038                                                         using_list [i] = ((UsingEntry) using_clauses [i]).Name.ToString ();
1039                                         }
1040
1041                                         symfile_id = CodeGen.SymbolWriter.DefineNamespace (ns.Name, file.SourceFileEntry, using_list, parent_id);
1042                                 }
1043                                 return symfile_id;
1044                         }
1045                 }
1046
1047                 static void MsgtryRef (string s)
1048                 {
1049                         Console.WriteLine ("    Try using -r:" + s);
1050                 }
1051
1052                 static void MsgtryPkg (string s)
1053                 {
1054                         Console.WriteLine ("    Try using -pkg:" + s);
1055                 }
1056
1057                 public static void Error_GlobalNamespaceRedefined (Location loc)
1058                 {
1059                         Report.Error (1681, loc, "You cannot redefine the global extern alias");
1060                 }
1061
1062                 public static void Error_NamespaceNotFound (Location loc, string name)
1063                 {
1064                         Report.Error (246, loc, "The type or namespace name `{0}' could not be found. Are you missing a using directive or an assembly reference?",
1065                                 name);
1066
1067                         switch (name) {
1068                         case "Gtk": case "GtkSharp":
1069                                 MsgtryPkg ("gtk-sharp");
1070                                 break;
1071
1072                         case "Gdk": case "GdkSharp":
1073                                 MsgtryPkg ("gdk-sharp");
1074                                 break;
1075
1076                         case "Glade": case "GladeSharp":
1077                                 MsgtryPkg ("glade-sharp");
1078                                 break;
1079
1080                         case "System.Drawing":
1081                         case "System.Web.Services":
1082                         case "System.Web":
1083                         case "System.Data":
1084                         case "System.Windows.Forms":
1085                                 MsgtryRef (name);
1086                                 break;
1087                         }
1088                 }
1089
1090                 /// <summary>
1091                 ///   Used to validate that all the using clauses are correct
1092                 ///   after we are finished parsing all the files.
1093                 /// </summary>
1094                 void VerifyUsing ()
1095                 {
1096                         if (extern_aliases != null) {
1097                                 foreach (DictionaryEntry de in extern_aliases)
1098                                         ((AliasEntry) de.Value).Resolve ();
1099                         }
1100
1101                         if (using_clauses != null) {
1102                                 foreach (UsingEntry ue in using_clauses)
1103                                         ue.Resolve ();
1104                         }
1105
1106                         if (aliases != null) {
1107                                 foreach (DictionaryEntry de in aliases)
1108                                         ((AliasEntry) de.Value).Resolve ();
1109                         }
1110                 }
1111
1112                 /// <summary>
1113                 ///   Used to validate that all the using clauses are correct
1114                 ///   after we are finished parsing all the files.
1115                 /// </summary>
1116                 static public void VerifyAllUsing ()
1117                 {
1118                         foreach (NamespaceEntry entry in entries)
1119                                 entry.VerifyUsing ();
1120                 }
1121
1122                 public string GetSignatureForError ()
1123                 {
1124                         return ns.GetSignatureForError ();
1125                 }
1126
1127                 public override string ToString ()
1128                 {
1129                         return ns.ToString ();
1130                 }
1131         }
1132 }