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 // Copyright 2001 Ximian, Inc.
   9 // Copyright 2003-2008 Novell, Inc.
  10 //
  11 using System;
  12 using System.Collections;
  13 using System.Collections.Specialized;
  14 using System.Reflection;
  15
  16 namespace Mono.CSharp {
  17
  18         public class RootNamespace : Namespace {
  19                 //
  20                 // Points to Mono's GetNamespaces method, an
  21                 // optimization when running on Mono to fetch all the
  22                 // namespaces in an assembly
  23                 //
  24                 static MethodInfo get_namespaces_method;
  25
  26                 string alias_name;
  27                 protected Assembly [] referenced_assemblies;
  28
  29                 Hashtable all_namespaces;
  30
  31                 static ListDictionary root_namespaces;
  32                 public static GlobalRootNamespace Global;
  33
  34                 static RootNamespace ()
  35                 {
  36                         get_namespaces_method = typeof (Assembly).GetMethod ("GetNamespaces", BindingFlags.Instance | BindingFlags.NonPublic);
  37
  38                         Reset ();
  39                 }
  40
  41                 public static void Reset ()
  42                 {
  43                         root_namespaces = new ListDictionary ();
  44                         Global = new GlobalRootNamespace ();
  45                         root_namespaces ["global"] = Global;
  46                 }
  47
  48                 protected RootNamespace (string alias_name)
  49                         : base (null, String.Empty)
  50                 {
  51                         this.alias_name = alias_name;
  52                         referenced_assemblies = new Assembly [0];
  53
  54                         all_namespaces = new Hashtable ();
  55                         all_namespaces.Add ("", this);
  56                 }
  57
  58                 public void AddAssemblyReference (Assembly a)
  59                 {
  60                         foreach (Assembly assembly in referenced_assemblies) {
  61                                 if (a == assembly)
  62                                         return;
  63                         }
  64
  65                         // How to test whether attribute exists without loading the assembly :-(
  66 #if NET_2_1
  67                         const string SystemCore = "System.Core, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e";
  68 #else
  69                         const string SystemCore = "System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089";
  70 #endif
  71                         if (TypeManager.extension_attribute_type == null &&
  72                                 a.FullName == SystemCore) {
  73                                 TypeManager.extension_attribute_type = a.GetType("System.Runtime.CompilerServices.ExtensionAttribute");
  74                         }
  75
  76                         int top = referenced_assemblies.Length;
  77                         Assembly [] n = new Assembly [top + 1];
  78                         referenced_assemblies.CopyTo (n, 0);
  79                         n [top] = a;
  80                         referenced_assemblies = n;
  81                 }
  82
  83                 public static void DefineRootNamespace (string alias, Assembly assembly)
  84                 {
  85                         if (alias == "global") {
  86                                 NamespaceEntry.Error_GlobalNamespaceRedefined (Location.Null);
  87                                 return;
  88                         }
  89
  90                         RootNamespace retval = GetRootNamespace (alias);
  91                         if (retval == null) {
  92                                 retval = new RootNamespace (alias);
  93                                 root_namespaces.Add (alias, retval);
  94                         }
  95
  96                         retval.AddAssemblyReference (assembly);
  97                 }
  98
  99                 public static RootNamespace GetRootNamespace (string name)
 100                 {
 101                         return (RootNamespace) root_namespaces [name];
 102                 }
 103
 104                 public static void ComputeNamespaces ()
 105                 {
 106                         foreach (RootNamespace rn in root_namespaces.Values) {
 107                                 foreach (Assembly a in rn.referenced_assemblies) {
 108                                         try {
 109                                                 rn.ComputeNamespaces (a);
 110                                         } catch (TypeLoadException e) {
 111                                                 Report.Error (11, Location.Null, e.Message);
 112                                         } catch (System.IO.FileNotFoundException) {
 113                                                 Report.Error (12, Location.Null, "An assembly `{0}' is used without being referenced",
 114                                                         a.FullName);
 115                                         }
 116                                 }
 117                         }
 118                 }
 119
 120                 public virtual Type LookupTypeReflection (string name, Location loc)
 121                 {
 122                         Type found_type = null;
 123
 124                         foreach (Assembly a in referenced_assemblies) {
 125                                 Type t = GetTypeInAssembly (a, name);
 126                                 if (t == null)
 127                                         continue;
 128
 129                                 if (found_type == null) {
 130                                         found_type = t;
 131                                         continue;
 132                                 }
 133
 134                                 Report.SymbolRelatedToPreviousError (found_type);
 135                                 Report.SymbolRelatedToPreviousError (t);
 136                                 Report.Error (433, loc, "The imported type `{0}' is defined multiple times", name);
 137
 138                                 return found_type;
 139                         }
 140
 141                         return found_type;
 142                 }
 143
 144                 public void RegisterNamespace (Namespace child)
 145                 {
 146                         if (child != this)
 147                                 all_namespaces.Add (child.Name, child);
 148                 }
 149
 150                 public bool IsNamespace (string name)
 151                 {
 152                         return all_namespaces.Contains (name);
 153                 }
 154
 155                 protected void RegisterNamespace (string dotted_name)
 156                 {
 157                         if (dotted_name != null && dotted_name.Length != 0 && ! IsNamespace (dotted_name))
 158                                 GetNamespace (dotted_name, true);
 159                 }
 160
 161                 void RegisterExtensionMethodClass (Type t)
 162                 {
 163                         string n = t.Namespace;
 164                         Namespace ns = n == null ? Global : (Namespace)all_namespaces [n];
 165                         if (ns == null)
 166                                 ns = GetNamespace (n, true);
 167
 168                         ns.RegisterExternalExtensionMethodClass (t);
 169                 }
 170
 171                 protected void ComputeNamespaces (Assembly assembly)
 172                 {
 173                         bool contains_extension_methods = TypeManager.extension_attribute_type != null &&
 174                                         assembly.IsDefined(TypeManager.extension_attribute_type, false);
 175
 176                         if (get_namespaces_method != null && !contains_extension_methods) {
 177                                 string [] namespaces = (string []) get_namespaces_method.Invoke (assembly, null);
 178                                 foreach (string ns in namespaces)
 179                                         RegisterNamespace (ns);
 180                                 return;
 181                         }
 182
 183                         foreach (Type t in assembly.GetExportedTypes ()) {
 184                                 if ((t.Attributes & Class.StaticClassAttribute) == Class.StaticClassAttribute &&
 185                                         contains_extension_methods && t.IsDefined (TypeManager.extension_attribute_type, false))
 186                                         RegisterExtensionMethodClass (t);
 187                                 else
 188                                         RegisterNamespace (t.Namespace);
 189                         }
 190                 }
 191
 192                 protected static Type GetTypeInAssembly (Assembly assembly, string name)
 193                 {
 194                         Type t = assembly.GetType (name);
 195                         if (t == null)
 196                                 return null;
 197
 198                         if (t.IsPointer)
 199                                 throw new InternalErrorException ("Use GetPointerType() to get a pointer");
 200
 201                         TypeAttributes ta = t.Attributes & TypeAttributes.VisibilityMask;
 202                         if (ta == TypeAttributes.NestedPrivate)
 203                                 return null;
 204
 205                         if ((ta == TypeAttributes.NotPublic ||
 206                              ta == TypeAttributes.NestedAssembly ||
 207                              ta == TypeAttributes.NestedFamANDAssem) &&
 208                             !TypeManager.IsThisOrFriendAssembly (t.Assembly))
 209                                 return null;
 210
 211                         return t;
 212                 }
 213
 214                 public override string ToString ()
 215                 {
 216                         return String.Format ("RootNamespace ({0}::)", alias_name);
 217                 }
 218
 219                 public override string GetSignatureForError ()
 220                 {
 221                         return alias_name + "::";
 222                 }
 223         }
 224
 225         public class GlobalRootNamespace : RootNamespace {
 226                 Module [] modules;
 227
 228                 public GlobalRootNamespace ()
 229                         : base ("global")
 230                 {
 231                 }
 232
 233                 public Assembly [] Assemblies {
 234                     get { return referenced_assemblies; }
 235                 }
 236
 237                 public Module [] Modules {
 238                         get { return modules; }
 239                 }
 240
 241                 public void AddModuleReference (Module m)
 242                 {
 243                         int top = modules != null ? modules.Length : 0;
 244                         Module [] n = new Module [top + 1];
 245                         if (modules != null)
 246                                 modules.CopyTo (n, 0);
 247                         n [top] = m;
 248                         modules = n;
 249
 250                         if (m == CodeGen.Module.Builder)
 251                                 return;
 252
 253                         foreach (Type t in m.GetTypes ())
 254                                 RegisterNamespace (t.Namespace);
 255                 }
 256
 257                 public override void Error_NamespaceDoesNotExist(DeclSpace ds, Location loc, string name)
 258                 {
 259                         Report.Error (400, loc, "The type or namespace name `{0}' could not be found in the global namespace (are you missing an assembly reference?)",
 260                                 name);
 261                 }
 262
 263                 public override Type LookupTypeReflection (string name, Location loc)
 264                 {
 265                         Type found_type = base.LookupTypeReflection (name, loc);
 266
 267                         if (modules != null) {
 268                                 foreach (Module module in modules) {
 269                                         Type t = module.GetType (name);
 270                                         if (t == null)
 271                                                 continue;
 272
 273                                         if (found_type == null) {
 274                                                 found_type = t;
 275                                                 continue;
 276                                         }
 277
 278                                         Report.SymbolRelatedToPreviousError (found_type);
 279                                         if (loc.IsNull) {
 280                                                 DeclSpace ds = TypeManager.LookupDeclSpace (t);
 281                                                 Report.Warning (1685, 1, ds.Location, "The type `{0}' conflicts with the predefined type `{1}' and will be ignored",
 282                                                         ds.GetSignatureForError (), TypeManager.CSharpName (found_type));
 283                                                 return found_type;
 284                                         }
 285                                         Report.SymbolRelatedToPreviousError (t);
 286                                         Report.Warning (436, 2, loc, "The type `{0}' conflicts with the imported type `{1}'. Ignoring the imported type definition",
 287                                                 TypeManager.CSharpName (t), TypeManager.CSharpName (found_type));
 288                                         return t;
 289                                 }
 290                         }
 291
 292                         return found_type;
 293                 }
 294         }
 295
 296         /// <summary>
 297         ///   Keeps track of the namespaces defined in the C# code.
 298         ///
 299         ///   This is an Expression to allow it to be referenced in the
 300         ///   compiler parse/intermediate tree during name resolution.
 301         /// </summary>
 302         public class Namespace : FullNamedExpression {
 303
 304                 Namespace parent;
 305                 string fullname;
 306                 IDictionary namespaces;
 307                 IDictionary declspaces;
 308                 Hashtable cached_types;
 309                 RootNamespace root;
 310                 ArrayList external_exmethod_classes;
 311
 312                 public readonly MemberName MemberName;
 313
 314                 /// <summary>
 315                 ///   Constructor Takes the current namespace and the
 316                 ///   name.  This is bootstrapped with parent == null
 317                 ///   and name = ""
 318                 /// </summary>
 319                 public Namespace (Namespace parent, string name)
 320                 {
 321                         // Expression members.
 322                         this.eclass = ExprClass.Namespace;
 323                         this.Type = typeof (Namespace);
 324                         this.loc = Location.Null;
 325
 326                         this.parent = parent;
 327
 328                         if (parent != null)
 329                                 this.root = parent.root;
 330                         else
 331                                 this.root = this as RootNamespace;
 332
 333                         if (this.root == null)
 334                                 throw new InternalErrorException ("Root namespaces must be created using RootNamespace");
 335
 336                         string pname = parent != null ? parent.fullname : "";
 337
 338                         if (pname == "")
 339                                 fullname = name;
 340                         else
 341                                 fullname = parent.fullname + "." + name;
 342
 343                         if (fullname == null)
 344                                 throw new InternalErrorException ("Namespace has a null fullname");
 345
 346                         if (parent != null && parent.MemberName != MemberName.Null)
 347                                 MemberName = new MemberName (parent.MemberName, name);
 348                         else if (name.Length == 0)
 349                                 MemberName = MemberName.Null;
 350                         else
 351                                 MemberName = new MemberName (name);
 352
 353                         namespaces = new HybridDictionary ();
 354                         cached_types = new Hashtable ();
 355
 356                         root.RegisterNamespace (this);
 357                 }
 358
 359                 public override Expression DoResolve (EmitContext ec)
 360                 {
 361                         return this;
 362                 }
 363
 364                 public virtual void Error_NamespaceDoesNotExist (DeclSpace ds, Location loc, string name)
 365                 {
 366                         if (name.IndexOf ('`') > 0) {
 367                                 FullNamedExpression retval = Lookup (ds, SimpleName.RemoveGenericArity (name), loc);
 368                                 if (retval != null) {
 369                                         Error_TypeArgumentsCannotBeUsed (retval.Type, loc);
 370                                         return;
 371                                 }
 372                         } else {
 373                                 Type t = LookForAnyGenericType (name);
 374                                 if (t != null) {
 375                                         Error_InvalidNumberOfTypeArguments (t, loc);
 376                                         return;
 377                                 }
 378                         }
 379
 380                         Report.Error (234, loc, "The type or namespace name `{0}' does not exist in the namespace `{1}'. Are you missing an assembly reference?",
 381                                 name, GetSignatureForError ());
 382                 }
 383
 384                 public static void Error_InvalidNumberOfTypeArguments (Type t, Location loc)
 385                 {
 386                         Report.SymbolRelatedToPreviousError (t);
 387                         Report.Error (305, loc, "Using the generic type `{0}' requires `{1}' type argument(s)",
 388                                 TypeManager.CSharpName(t), TypeManager.GetNumberOfTypeArguments(t).ToString());
 389                 }
 390
 391                 public static void Error_TypeArgumentsCannotBeUsed (Type t, Location loc)
 392                 {
 393                         Report.SymbolRelatedToPreviousError (t);
 394                         Error_TypeArgumentsCannotBeUsed (loc, "type", TypeManager.CSharpName (t));
 395                 }
 396
 397                 public static void Error_TypeArgumentsCannotBeUsed (MethodBase mi, Location loc)
 398                 {
 399                         Report.SymbolRelatedToPreviousError (mi);
 400                         Error_TypeArgumentsCannotBeUsed (loc, "method", TypeManager.CSharpSignature (mi));
 401                 }
 402
 403                 static void Error_TypeArgumentsCannotBeUsed (Location loc, string type, string name)
 404                 {
 405                         Report.Error(308, loc, "The non-generic {0} `{1}' cannot be used with the type arguments",
 406                                 type, name);
 407                 }
 408
 409                 public override string GetSignatureForError ()
 410                 {
 411                         return fullname;
 412                 }
 413
 414                 public Namespace GetNamespace (string name, bool create)
 415                 {
 416                         int pos = name.IndexOf ('.');
 417
 418                         Namespace ns;
 419                         string first;
 420                         if (pos >= 0)
 421                                 first = name.Substring (0, pos);
 422                         else
 423                                 first = name;
 424
 425                         ns = (Namespace) namespaces [first];
 426                         if (ns == null) {
 427                                 if (!create)
 428                                         return null;
 429
 430                                 ns = new Namespace (this, first);
 431                                 namespaces.Add (first, ns);
 432                         }
 433
 434                         if (pos >= 0)
 435                                 ns = ns.GetNamespace (name.Substring (pos + 1), create);
 436
 437                         return ns;
 438                 }
 439
 440                 public bool HasDefinition (string name)
 441                 {
 442                         return declspaces != null && declspaces [name] != null;
 443                 }
 444
 445                 TypeExpr LookupType (string name, Location loc)
 446                 {
 447                         if (cached_types.Contains (name))
 448                                 return cached_types [name] as TypeExpr;
 449
 450                         Type t = null;
 451                         if (declspaces != null) {
 452                                 DeclSpace tdecl = declspaces [name] as DeclSpace;
 453                                 if (tdecl != null) {
 454                                         //
 455                                         // Note that this is not:
 456                                         //
 457                                         //   t = tdecl.DefineType ()
 458                                         //
 459                                         // This is to make it somewhat more useful when a DefineType
 460                                         // fails due to problems in nested types (more useful in the sense
 461                                         // of fewer misleading error messages)
 462                                         //
 463                                         tdecl.DefineType ();
 464                                         t = tdecl.TypeBuilder;
 465
 466                                         if (RootContext.EvalMode){
 467                                                 // Replace the TypeBuilder with a System.Type, as
 468                                                 // Reflection.Emit fails otherwise (we end up pretty
 469                                                 // much with Random type definitions later on).
 470                                                 Type tt = t.Assembly.GetType (t.Name);
 471                                                 if (tt != null)
 472                                                         t = tt;
 473                                         }
 474                                 }
 475                         }
 476                         string lookup = t != null ? t.FullName : (fullname.Length == 0 ? name : fullname + "." + name);
 477                         Type rt = root.LookupTypeReflection (lookup, loc);
 478
 479                         // HACK: loc.IsNull when the type is core type
 480                         if (t == null || (rt != null && loc.IsNull))
 481                                 t = rt;
 482
 483                         TypeExpr te = t == null ? null : new TypeExpression (t, Location.Null);
 484                         cached_types [name] = te;
 485                         return te;
 486                 }
 487
 488                 ///
 489                 /// Used for better error reporting only
 490                 ///
 491                 public Type LookForAnyGenericType (string typeName)
 492                 {
 493                         if (declspaces == null)
 494                                 return null;
 495
 496                         typeName = SimpleName.RemoveGenericArity (typeName);
 497
 498                         foreach (DictionaryEntry de in declspaces) {
 499                                 string type_item = (string) de.Key;
 500                                 int pos = type_item.LastIndexOf ('`');
 501                                 if (pos == typeName.Length && String.Compare (typeName, 0, type_item, 0, pos) == 0)
 502                                         return ((DeclSpace) de.Value).TypeBuilder;
 503                         }
 504                         return null;
 505                 }
 506
 507                 public FullNamedExpression Lookup (DeclSpace ds, string name, Location loc)
 508                 {
 509                         if (namespaces.Contains (name))
 510                                 return (Namespace) namespaces [name];
 511
 512                         return LookupType (name, loc);
 513                 }
 514
 515                 public void RegisterExternalExtensionMethodClass (Type type)
 516                 {
 517                         if (external_exmethod_classes == null)
 518                                 external_exmethod_classes = new ArrayList ();
 519
 520                         external_exmethod_classes.Add (type);
 521                 }
 522
 523                 ///
 524                 /// Looks for extension method in this namespace
 525                 ///
 526                 public ArrayList LookupExtensionMethod (Type extensionType, ClassOrStruct currentClass, string name)
 527                 {
 528                         ArrayList found = null;
 529
 530                         if (declspaces != null) {
 531                                 IEnumerator e = declspaces.Values.GetEnumerator ();
 532                                 e.Reset ();
 533                                 while (e.MoveNext ()) {
 534                                         Class c = e.Current as Class;
 535                                         if (c == null)
 536                                                 continue;
 537
 538                                         if (!c.IsStaticClass)
 539                                                 continue;
 540
 541                                         ArrayList res = c.MemberCache.FindExtensionMethods (extensionType, name, c != currentClass);
 542                                         if (res == null)
 543                                                 continue;
 544
 545                                         if (found == null)
 546                                                 found = res;
 547                                         else
 548                                                 found.AddRange (res);
 549                                 }
 550                         }
 551
 552                         if (external_exmethod_classes == null)
 553                                 return found;
 554
 555                         foreach (Type t in external_exmethod_classes) {
 556                                 MemberCache m = TypeHandle.GetMemberCache (t);
 557                                 ArrayList res = m.FindExtensionMethods (extensionType, name, true);
 558                                 if (res == null)
 559                                         continue;
 560
 561                                 if (found == null)
 562                                         found = res;
 563                                 else
 564                                         found.AddRange (res);
 565                         }
 566
 567                         return found;
 568                 }
 569
 570                 public void AddDeclSpace (string name, DeclSpace ds)
 571                 {
 572                         if (declspaces == null)
 573                                 declspaces = new HybridDictionary ();
 574                         declspaces.Add (name, ds);
 575                 }
 576
 577                 public void RemoveDeclSpace (string name)
 578                 {
 579                         declspaces.Remove (name);
 580                 }
 581
 582                 /// <summary>
 583                 ///   The qualified name of the current namespace
 584                 /// </summary>
 585                 public string Name {
 586                         get { return fullname; }
 587                 }
 588
 589                 /// <summary>
 590                 ///   The parent of this namespace, used by the parser to "Pop"
 591                 ///   the current namespace declaration
 592                 /// </summary>
 593                 public Namespace Parent {
 594                         get { return parent; }
 595                 }
 596         }
 597
 598         //
 599         // Namespace container as created by the parser
 600         //
 601         public class NamespaceEntry : IResolveContext {
 602
 603                 class UsingEntry {
 604                         readonly MemberName name;
 605                         Namespace resolved;
 606
 607                         public UsingEntry (MemberName name)
 608                         {
 609                                 this.name = name;
 610                         }
 611
 612                         public string GetSignatureForError ()
 613                         {
 614                                 return name.GetSignatureForError ();
 615                         }
 616
 617                         public Location Location {
 618                                 get { return name.Location; }
 619                         }
 620
 621                         public MemberName MemberName {
 622                                 get { return name; }
 623                         }
 624
 625                         public string Name {
 626                                 get { return GetSignatureForError (); }
 627                         }
 628
 629                         public Namespace Resolve (IResolveContext rc)
 630                         {
 631                                 if (resolved != null)
 632                                         return resolved;
 633
 634                                 FullNamedExpression fne = name.GetTypeExpression ().ResolveAsTypeStep (rc, false);
 635                                 if (fne == null)
 636                                         return null;
 637
 638                                 resolved = fne as Namespace;
 639                                 if (resolved == null) {
 640                                         Report.SymbolRelatedToPreviousError (fne.Type);
 641                                         Report.Error (138, Location,
 642                                                 "`{0}' is a type not a namespace. A using namespace directive can only be applied to namespaces",
 643                                                 GetSignatureForError ());
 644                                 }
 645                                 return resolved;
 646                         }
 647
 648                         public override string ToString ()
 649                         {
 650                                 return Name;
 651                         }
 652                 }
 653
 654                 class UsingAliasEntry {
 655                         public readonly string Alias;
 656                         public Location Location;
 657
 658                         public UsingAliasEntry (string alias, Location loc)
 659                         {
 660                                 this.Alias = alias;
 661                                 this.Location = loc;
 662                         }
 663
 664                         public virtual FullNamedExpression Resolve (IResolveContext rc)
 665                         {
 666                                 FullNamedExpression fne = RootNamespace.GetRootNamespace (Alias);
 667                                 if (fne == null) {
 668                                         Report.Error (430, Location,
 669                                                 "The extern alias `{0}' was not specified in -reference option",
 670                                                 Alias);
 671                                 }
 672
 673                                 return fne;
 674                         }
 675
 676                         public override string ToString ()
 677                         {
 678                                 return Alias;
 679                         }
 680
 681                 }
 682
 683                 class LocalUsingAliasEntry : UsingAliasEntry {
 684                         Expression resolved;
 685                         MemberName value;
 686
 687                         public LocalUsingAliasEntry (string alias, MemberName name, Location loc)
 688                                 : base (alias, loc)
 689                         {
 690                                 this.value = name;
 691                         }
 692
 693                         public override FullNamedExpression Resolve (IResolveContext rc)
 694                         {
 695                                 if (resolved != null)
 696                                         return (FullNamedExpression)resolved;
 697
 698                                 resolved = value.GetTypeExpression ().ResolveAsTypeStep (rc, false);
 699                                 if (resolved == null)
 700                                         return null;
 701
 702                                 // FIXME: This is quite wrong, the accessibility is not global
 703                                 if (resolved.Type != null) {
 704                                         TypeAttributes attr = resolved.Type.Attributes & TypeAttributes.VisibilityMask;
 705                                         if (attr == TypeAttributes.NestedPrivate || attr == TypeAttributes.NestedFamily ||
 706                                                 ((attr == TypeAttributes.NestedFamORAssem || attr == TypeAttributes.NestedAssembly) &&
 707                                                 TypeManager.LookupDeclSpace (resolved.Type) == null)) {
 708                                                 Expression.ErrorIsInaccesible (resolved.Location, resolved.GetSignatureForError ());
 709                                                 return null;
 710                                         }
 711                                 }
 712
 713                                 return (FullNamedExpression)resolved;
 714                         }
 715
 716                         public override string ToString ()
 717                         {
 718                                 return String.Format ("{0} = {1}", Alias, value.GetSignatureForError ());
 719                         }
 720                 }
 721
 722                 Namespace ns;
 723                 NamespaceEntry parent, implicit_parent;
 724                 CompilationUnit file;
 725                 int symfile_id;
 726
 727                 // Namespace using import block
 728                 ArrayList using_aliases;
 729                 ArrayList using_clauses;
 730                 public bool DeclarationFound = false;
 731                 // End
 732
 733                 public readonly bool IsImplicit;
 734                 public readonly DeclSpace SlaveDeclSpace;
 735                 static readonly Namespace [] empty_namespaces = new Namespace [0];
 736                 Namespace [] namespace_using_table;
 737
 738                 static ArrayList entries = new ArrayList ();
 739
 740                 public static void Reset ()
 741                 {
 742                         entries = new ArrayList ();
 743                 }
 744
 745                 public NamespaceEntry (NamespaceEntry parent, CompilationUnit file, string name)
 746                 {
 747                         this.parent = parent;
 748                         this.file = file;
 749                         entries.Add (this);
 750
 751                         if (parent != null)
 752                                 ns = parent.NS.GetNamespace (name, true);
 753                         else if (name != null)
 754                                 ns = RootNamespace.Global.GetNamespace (name, true);
 755                         else
 756                                 ns = RootNamespace.Global;
 757                         SlaveDeclSpace = new RootDeclSpace (this);
 758                 }
 759
 760                 private NamespaceEntry (NamespaceEntry parent, CompilationUnit file, Namespace ns, bool slave)
 761                 {
 762                         this.parent = parent;
 763                         this.file = file;
 764                         this.IsImplicit = true;
 765                         this.ns = ns;
 766                         this.SlaveDeclSpace = slave ? new RootDeclSpace (this) : null;
 767                 }
 768
 769                 //
 770                 // Populates the Namespace with some using declarations, used by the
 771                 // eval mode.
 772                 //
 773                 public void Populate (ArrayList source_using_aliases, ArrayList source_using_clauses)
 774                 {
 775                         foreach (UsingAliasEntry uae in source_using_aliases){
 776                                 if (using_aliases == null)
 777                                         using_aliases = new ArrayList ();
 778
 779                                 using_aliases.Add (uae);
 780                         }
 781
 782                         foreach (UsingEntry ue in source_using_clauses){
 783                                 if (using_clauses == null)
 784                                         using_clauses = new ArrayList ();
 785
 786                                 using_clauses.Add (ue);
 787                         }
 788                 }
 789
 790                 //
 791                 // Extracts the using alises and using clauses into a couple of
 792                 // arrays that might already have the same information;  Used by the
 793                 // C# Eval mode.
 794                 //
 795                 public void Extract (ArrayList out_using_aliases, ArrayList out_using_clauses)
 796                 {
 797                         if (using_aliases != null){
 798                                 foreach (UsingAliasEntry uae in using_aliases){
 799                                         bool replaced = false;
 800
 801                                         for (int i = 0; i < out_using_aliases.Count; i++){
 802                                                 UsingAliasEntry out_uea = (UsingAliasEntry) out_using_aliases [i];
 803
 804                                                 if (out_uea.Alias == uae.Alias){
 805                                                         out_using_aliases [i] = uae;
 806                                                         replaced = true;
 807                                                         break;
 808                                                 }
 809                                         }
 810                                         if (!replaced)
 811                                                 out_using_aliases.Add (uae);
 812                                 }
 813                         }
 814
 815                         if (using_clauses != null){
 816                                 foreach (UsingEntry ue in using_clauses){
 817                                         bool found = false;
 818
 819                                         foreach (UsingEntry out_ue in out_using_clauses)
 820                                                 if (out_ue.Name == ue.Name){
 821                                                         found = true;
 822                                                         break;
 823                                                 }
 824                                         if (!found)
 825                                                 out_using_clauses.Add (ue);
 826                                 }
 827                         }
 828                 }
 829
 830                 //
 831                 // According to section 16.3.1 (using-alias-directive), the namespace-or-type-name is
 832                 // resolved as if the immediately containing namespace body has no using-directives.
 833                 //
 834                 // Section 16.3.2 says that the same rule is applied when resolving the namespace-name
 835                 // in the using-namespace-directive.
 836                 //
 837                 // To implement these rules, the expressions in the using directives are resolved using
 838                 // the "doppelganger" (ghostly bodiless duplicate).
 839                 //
 840                 NamespaceEntry doppelganger;
 841                 NamespaceEntry Doppelganger {
 842                         get {
 843                                 if (!IsImplicit && doppelganger == null) {
 844                                         doppelganger = new NamespaceEntry (ImplicitParent, file, ns, true);
 845                                         doppelganger.using_aliases = using_aliases;
 846                                 }
 847                                 return doppelganger;
 848                         }
 849                 }
 850
 851                 public Namespace NS {
 852                         get { return ns; }
 853                 }
 854
 855                 public NamespaceEntry Parent {
 856                         get { return parent; }
 857                 }
 858
 859                 public NamespaceEntry ImplicitParent {
 860                         get {
 861                                 if (parent == null)
 862                                         return null;
 863                                 if (implicit_parent == null) {
 864                                         implicit_parent = (parent.NS == ns.Parent)
 865                                                 ? parent
 866                                                 : new NamespaceEntry (parent, file, ns.Parent, false);
 867                                 }
 868                                 return implicit_parent;
 869                         }
 870                 }
 871
 872                 /// <summary>
 873                 ///   Records a new namespace for resolving name references
 874                 /// </summary>
 875                 public void AddUsing (MemberName name, Location loc)
 876                 {
 877                         if (DeclarationFound){
 878                                 Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
 879                         }
 880
 881                         if (using_clauses == null) {
 882                                 using_clauses = new ArrayList ();
 883                         } else {
 884                                 foreach (UsingEntry old_entry in using_clauses) {
 885                                         if (name.Equals (old_entry.MemberName)) {
 886                                                 Report.SymbolRelatedToPreviousError (old_entry.Location, old_entry.GetSignatureForError ());
 887                                                 Report.Warning (105, 3, loc, "The using directive for `{0}' appeared previously in this namespace", name.GetSignatureForError ());
 888                                                 return;
 889                                         }
 890                                 }
 891                         }
 892
 893                         using_clauses.Add (new UsingEntry (name));
 894                 }
 895
 896                 public void AddUsingAlias (string alias, MemberName name, Location loc)
 897                 {
 898                         // TODO: This is parser bussines
 899                         if (DeclarationFound){
 900                                 Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
 901                         }
 902
 903                         if (RootContext.Version != LanguageVersion.ISO_1 && alias == "global")
 904                                 Report.Warning (440, 2, loc, "An alias named `global' will not be used when resolving 'global::';" +
 905                                         " the global namespace will be used instead");
 906
 907                         AddUsingAlias (new LocalUsingAliasEntry (alias, name, loc));
 908                 }
 909
 910                 public void AddUsingExternalAlias (string alias, Location loc)
 911                 {
 912                         // TODO: Do this in parser
 913                         bool not_first = using_clauses != null || DeclarationFound;
 914                         if (using_aliases != null && !not_first) {
 915                                 foreach (UsingAliasEntry uae in using_aliases) {
 916                                         if (uae is LocalUsingAliasEntry) {
 917                                                 not_first = true;
 918                                                 break;
 919                                         }
 920                                 }
 921                         }
 922
 923                         if (not_first)
 924                                 Report.Error (439, loc, "An extern alias declaration must precede all other elements");
 925
 926                         if (alias == "global") {
 927                                 Error_GlobalNamespaceRedefined (loc);
 928                                 return;
 929                         }
 930
 931                         AddUsingAlias (new UsingAliasEntry (alias, loc));
 932                 }
 933
 934                 void AddUsingAlias (UsingAliasEntry uae)
 935                 {
 936                         if (using_aliases == null) {
 937                                 using_aliases = new ArrayList ();
 938                         } else {
 939                                 foreach (UsingAliasEntry entry in using_aliases) {
 940                                         if (uae.Alias == entry.Alias) {
 941                                                 Report.SymbolRelatedToPreviousError (uae.Location, uae.Alias);
 942                                                 Report.Error (1537, entry.Location, "The using alias `{0}' appeared previously in this namespace",
 943                                                         entry.Alias);
 944                                                 return;
 945                                         }
 946                                 }
 947                         }
 948
 949                         using_aliases.Add (uae);
 950                 }
 951
 952                 ///
 953                 /// Does extension methods look up to find a method which matches name and extensionType.
 954                 /// Search starts from this namespace and continues hierarchically up to top level.
 955                 ///
 956                 public ExtensionMethodGroupExpr LookupExtensionMethod (Type extensionType, ClassOrStruct currentClass, string name, Location loc)
 957                 {
 958                         ArrayList candidates = null;
 959                         if (currentClass != null) {
 960                                 candidates = ns.LookupExtensionMethod (extensionType, currentClass, name);
 961                                 if (candidates != null)
 962                                         return new ExtensionMethodGroupExpr (candidates, this, extensionType, loc);
 963                         }
 964
 965                         foreach (Namespace n in GetUsingTable ()) {
 966                                 ArrayList a = n.LookupExtensionMethod (extensionType, null, name);
 967                                 if (a == null)
 968                                         continue;
 969
 970                                 if (candidates == null)
 971                                         candidates = a;
 972                                 else
 973                                         candidates.AddRange (a);
 974                         }
 975
 976                         if (candidates != null)
 977                                 return new ExtensionMethodGroupExpr (candidates, parent, extensionType, loc);
 978
 979                         if (parent == null)
 980                                 return null;
 981
 982                         //
 983                         // Inspect parent namespaces in namespace expression
 984                         //
 985                         Namespace parent_ns = ns.Parent;
 986                         do {
 987                                 candidates = parent_ns.LookupExtensionMethod (extensionType, null, name);
 988                                 if (candidates != null)
 989                                         return new ExtensionMethodGroupExpr (candidates, parent, extensionType, loc);
 990
 991                                 parent_ns = parent_ns.Parent;
 992                         } while (parent_ns != null);
 993
 994                         //
 995                         // Continue in parent scope
 996                         //
 997                         return parent.LookupExtensionMethod (extensionType, currentClass, name, loc);
 998                 }
 999
1000                 public FullNamedExpression LookupNamespaceOrType (DeclSpace ds, string name, Location loc, bool ignore_cs0104)
1001                 {
1002                         // Precondition: Only simple names (no dots) will be looked up with this function.
1003                         FullNamedExpression resolved = null;
1004                         for (NamespaceEntry curr_ns = this; curr_ns != null; curr_ns = curr_ns.ImplicitParent) {
1005                                 if ((resolved = curr_ns.Lookup (ds, name, loc, ignore_cs0104)) != null)
1006                                         break;
1007                         }
1008                         return resolved;
1009                 }
1010
1011                 static void Error_AmbiguousTypeReference (Location loc, string name, FullNamedExpression t1, FullNamedExpression t2)
1012                 {
1013                         Report.SymbolRelatedToPreviousError (t1.Type);
1014                         Report.SymbolRelatedToPreviousError (t2.Type);
1015                         Report.Error (104, loc, "`{0}' is an ambiguous reference between `{1}' and `{2}'",
1016                                 name, t1.GetSignatureForError (), t2.GetSignatureForError ());
1017                 }
1018
1019                 // Looks-up a alias named @name in this and surrounding namespace declarations
1020                 public FullNamedExpression LookupAlias (string name)
1021                 {
1022                         for (NamespaceEntry n = this; n != null; n = n.ImplicitParent) {
1023                                 if (n.using_aliases == null)
1024                                         continue;
1025
1026                                 foreach (UsingAliasEntry ue in n.using_aliases) {
1027                                         if (ue.Alias == name)
1028                                                 return ue.Resolve (Doppelganger);
1029                                 }
1030                         }
1031
1032                         return null;
1033                 }
1034
1035                 private FullNamedExpression Lookup (DeclSpace ds, string name, Location loc, bool ignore_cs0104)
1036                 {
1037                         //
1038                         // Check whether it's in the namespace.
1039                         //
1040                         FullNamedExpression fne = ns.Lookup (ds, name, loc);
1041
1042                         //
1043                         // Check aliases.
1044                         //
1045                         if (using_aliases != null) {
1046                                 foreach (UsingAliasEntry ue in using_aliases) {
1047                                         if (ue.Alias == name) {
1048                                                 if (fne != null) {
1049                                                         if (Doppelganger != null) {
1050                                                                 // TODO: Namespace has broken location
1051                                                                 //Report.SymbolRelatedToPreviousError (fne.Location, null);
1052                                                                 Report.SymbolRelatedToPreviousError (ue.Location, null);
1053                                                                 Report.Error (576, loc,
1054                                                                         "Namespace `{0}' contains a definition with same name as alias `{1}'",
1055                                                                         GetSignatureForError (), name);
1056                                                         } else {
1057                                                                 return fne;
1058                                                         }
1059                                                 }
1060
1061                                                 return ue.Resolve (Doppelganger);
1062                                         }
1063                                 }
1064                         }
1065
1066                         if (fne != null)
1067                                 return fne;
1068
1069                         if (IsImplicit)
1070                                 return null;
1071
1072                         //
1073                         // Check using entries.
1074                         //
1075                         FullNamedExpression match = null;
1076                         foreach (Namespace using_ns in GetUsingTable ()) {
1077                                 match = using_ns.Lookup (ds, name, loc);
1078                                 if (match == null || !(match is TypeExpr))
1079                                         continue;
1080                                 if (fne != null) {
1081                                         if (!ignore_cs0104)
1082                                                 Error_AmbiguousTypeReference (loc, name, fne, match);
1083                                         return null;
1084                                 }
1085                                 fne = match;
1086                         }
1087
1088                         return fne;
1089                 }
1090
1091                 Namespace [] GetUsingTable ()
1092                 {
1093                         if (namespace_using_table != null)
1094                                 return namespace_using_table;
1095
1096                         if (using_clauses == null) {
1097                                 namespace_using_table = empty_namespaces;
1098                                 return namespace_using_table;
1099                         }
1100
1101                         ArrayList list = new ArrayList (using_clauses.Count);
1102
1103                         foreach (UsingEntry ue in using_clauses) {
1104                                 Namespace using_ns = ue.Resolve (Doppelganger);
1105                                 if (using_ns == null)
1106                                         continue;
1107
1108                                 list.Add (using_ns);
1109                         }
1110
1111                         namespace_using_table = (Namespace[])list.ToArray (typeof (Namespace));
1112                         return namespace_using_table;
1113                 }
1114
1115                 static readonly string [] empty_using_list = new string [0];
1116
1117                 public int SymbolFileID {
1118                         get {
1119                                 if (symfile_id == 0 && file.SourceFileEntry != null) {
1120                                         int parent_id = parent == null ? 0 : parent.SymbolFileID;
1121
1122                                         string [] using_list = empty_using_list;
1123                                         if (using_clauses != null) {
1124                                                 using_list = new string [using_clauses.Count];
1125                                                 for (int i = 0; i < using_clauses.Count; i++)
1126                                                         using_list [i] = ((UsingEntry) using_clauses [i]).MemberName.GetTypeName ();
1127                                         }
1128
1129                                         symfile_id = SymbolWriter.DefineNamespace (ns.Name, file.CompileUnitEntry, using_list, parent_id);
1130                                 }
1131                                 return symfile_id;
1132                         }
1133                 }
1134
1135                 static void MsgtryRef (string s)
1136                 {
1137                         Console.WriteLine ("    Try using -r:" + s);
1138                 }
1139
1140                 static void MsgtryPkg (string s)
1141                 {
1142                         Console.WriteLine ("    Try using -pkg:" + s);
1143                 }
1144
1145                 public static void Error_GlobalNamespaceRedefined (Location loc)
1146                 {
1147                         Report.Error (1681, loc, "You cannot redefine the global extern alias");
1148                 }
1149
1150                 public static void Error_NamespaceNotFound (Location loc, string name)
1151                 {
1152                         if (RootContext.EvalMode){
1153                                 // Do not report this, it might be an error on the eval side, and we are lax there.
1154                                 return;
1155                         }
1156
1157                         Report.Error (246, loc, "The type or namespace name `{0}' could not be found. Are you missing a using directive or an assembly reference?",
1158                                 name);
1159
1160                         switch (name) {
1161                         case "Gtk": case "GtkSharp":
1162                                 MsgtryPkg ("gtk-sharp");
1163                                 break;
1164
1165                         case "Gdk": case "GdkSharp":
1166                                 MsgtryPkg ("gdk-sharp");
1167                                 break;
1168
1169                         case "Glade": case "GladeSharp":
1170                                 MsgtryPkg ("glade-sharp");
1171                                 break;
1172
1173                         case "System.Drawing":
1174                         case "System.Web.Services":
1175                         case "System.Web":
1176                         case "System.Data":
1177                         case "System.Windows.Forms":
1178                                 MsgtryRef (name);
1179                                 break;
1180                         }
1181                 }
1182
1183                 /// <summary>
1184                 ///   Used to validate that all the using clauses are correct
1185                 ///   after we are finished parsing all the files.
1186                 /// </summary>
1187                 void VerifyUsing ()
1188                 {
1189                         if (using_aliases != null) {
1190                                 foreach (UsingAliasEntry ue in using_aliases)
1191                                         ue.Resolve (Doppelganger);
1192                         }
1193
1194                         if (using_clauses != null) {
1195                                 foreach (UsingEntry ue in using_clauses)
1196                                         ue.Resolve (Doppelganger);
1197                         }
1198                 }
1199
1200                 /// <summary>
1201                 ///   Used to validate that all the using clauses are correct
1202                 ///   after we are finished parsing all the files.
1203                 /// </summary>
1204                 static public void VerifyAllUsing ()
1205                 {
1206                         foreach (NamespaceEntry entry in entries)
1207                                 entry.VerifyUsing ();
1208                 }
1209
1210                 public string GetSignatureForError ()
1211                 {
1212                         return ns.GetSignatureForError ();
1213                 }
1214
1215                 public override string ToString ()
1216                 {
1217                         return ns.ToString ();
1218                 }
1219
1220                 #region IResolveContext Members
1221
1222                 public DeclSpace DeclContainer {
1223                         get { return SlaveDeclSpace; }
1224                 }
1225
1226                 public bool IsInObsoleteScope {
1227                         get { return SlaveDeclSpace.IsInObsoleteScope; }
1228                 }
1229
1230                 public bool IsInUnsafeScope {
1231                         get { return SlaveDeclSpace.IsInUnsafeScope; }
1232                 }
1233
1234                 public DeclSpace GenericDeclContainer {
1235                         get { return SlaveDeclSpace; }
1236                 }
1237
1238                 #endregion
1239         }
1240 }