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                 protected readonly string alias_name;
  27                 protected Assembly [] referenced_assemblies;
  28
  29                 Hashtable all_namespaces;
  30
  31                 static RootNamespace ()
  32                 {
  33                         get_namespaces_method = typeof (Assembly).GetMethod ("GetNamespaces", BindingFlags.Instance | BindingFlags.NonPublic);
  34                 }
  35
  36                 public RootNamespace (string alias_name)
  37                         : base (null, String.Empty)
  38                 {
  39                         this.alias_name = alias_name;
  40                         referenced_assemblies = new Assembly [0];
  41
  42                         all_namespaces = new Hashtable ();
  43                         all_namespaces.Add ("", this);
  44                 }
  45
  46                 public void AddAssemblyReference (Assembly a)
  47                 {
  48                         foreach (Assembly assembly in referenced_assemblies) {
  49                                 if (a == assembly)
  50                                         return;
  51                         }
  52
  53                         int top = referenced_assemblies.Length;
  54                         Assembly [] n = new Assembly [top + 1];
  55                         referenced_assemblies.CopyTo (n, 0);
  56                         n [top] = a;
  57                         referenced_assemblies = n;
  58                 }
  59
  60                 public void ComputeNamespace (CompilerContext ctx, Type extensionType)
  61                 {
  62                         foreach (Assembly a in referenced_assemblies) {
  63                                 try {
  64                                         ComputeNamespaces (a, extensionType);
  65                                 } catch (TypeLoadException e) {
  66                                         ctx.Report.Error (11, Location.Null, e.Message);
  67                                 } catch (System.IO.FileNotFoundException) {
  68                                         ctx.Report.Error (12, Location.Null, "An assembly `{0}' is used without being referenced",
  69                                                 a.FullName);
  70                                 }
  71                         }
  72                 }
  73
  74                 public virtual Type LookupTypeReflection (CompilerContext ctx, string name, Location loc, bool must_be_unique)
  75                 {
  76                         // FIXME: Breaks dynamic
  77                         Assembly invocation_assembly = CodeGen.Assembly.Builder;
  78
  79                         Type found_type = null;
  80                         foreach (Assembly a in referenced_assemblies) {
  81                                 Type t = GetTypeInAssembly (invocation_assembly, a, name);
  82                                 if (t == null)
  83                                         continue;
  84
  85                                 if (!must_be_unique)
  86                                         return t;
  87
  88                                 if (found_type == null) {
  89                                         found_type = t;
  90                                         continue;
  91                                 }
  92
  93                                 // When type is forwarded
  94                                 if (t.Assembly == found_type.Assembly)
  95                                         continue;
  96
  97                                 ctx.Report.SymbolRelatedToPreviousError (found_type);
  98                                 ctx.Report.SymbolRelatedToPreviousError (t);
  99                                 if (loc.IsNull) {
 100                                         Error_AmbiguousPredefinedType (ctx, loc, name, found_type);
 101                                 } else {
 102                                         ctx.Report.Error (433, loc, "The imported type `{0}' is defined multiple times", name);
 103                                 }
 104
 105                                 return found_type;
 106                         }
 107
 108                         return found_type;
 109                 }
 110
 111                 //
 112                 // Returns the types starting with the given prefix
 113                 //
 114                 public ICollection CompletionGetTypesStartingWith (string prefix)
 115                 {
 116                         Hashtable result = null;
 117
 118                         foreach (Assembly a in referenced_assemblies){
 119                                 Type [] mtypes = a.GetTypes ();
 120
 121                                 foreach (Type t in mtypes){
 122                                         string f = t.FullName;
 123
 124                                         if (f.StartsWith (prefix) && (result == null || !result.Contains (f))){
 125                                                 if (result == null)
 126                                                         result = new Hashtable ();
 127
 128                                                 result [f] = f;
 129                                         }
 130                                 }
 131                         }
 132                         return result == null ? result : result.Keys;
 133                 }
 134
 135                 protected static void Error_AmbiguousPredefinedType (CompilerContext ctx, Location loc, string name, Type type)
 136                 {
 137                         ctx.Report.Warning (1685, 1, loc,
 138                                 "The predefined type `{0}' is ambiguous. Using definition from `{1}'",
 139                                 name, type.Assembly.FullName);
 140                 }
 141
 142                 public void RegisterNamespace (Namespace child)
 143                 {
 144                         if (child != this)
 145                                 all_namespaces.Add (child.Name, child);
 146                 }
 147
 148                 public bool IsNamespace (string name)
 149                 {
 150                         return all_namespaces.Contains (name);
 151                 }
 152
 153                 protected void RegisterNamespace (string dotted_name)
 154                 {
 155                         if (dotted_name != null && dotted_name.Length != 0 && ! IsNamespace (dotted_name))
 156                                 GetNamespace (dotted_name, true);
 157                 }
 158
 159                 void RegisterExtensionMethodClass (Type t)
 160                 {
 161                         string n = t.Namespace;
 162                         Namespace ns = n == null ? GlobalRootNamespace.Instance : (Namespace) all_namespaces[n];
 163                         if (ns == null)
 164                                 ns = GetNamespace (n, true);
 165
 166                         ns.RegisterExternalExtensionMethodClass (t);
 167                 }
 168
 169                 void ComputeNamespaces (Assembly assembly, Type extensionType)
 170                 {
 171                         bool contains_extension_methods = extensionType != null && assembly.IsDefined (extensionType, false);
 172
 173                         if (get_namespaces_method != null) {
 174                                 string [] namespaces = (string []) get_namespaces_method.Invoke (assembly, null);
 175                                 foreach (string ns in namespaces)
 176                                         RegisterNamespace (ns);
 177
 178                                 if (!contains_extension_methods)
 179                                         return;
 180                         }
 181
 182                         foreach (Type t in assembly.GetTypes ()) {
 183                                 if ((t.Attributes & Class.StaticClassAttribute) == Class.StaticClassAttribute &&
 184                                         contains_extension_methods && t.IsDefined (extensionType, false))
 185                                         RegisterExtensionMethodClass (t);
 186
 187                                 if (get_namespaces_method == null)
 188                                         RegisterNamespace (t.Namespace);
 189                         }
 190                 }
 191
 192                 protected static Type GetTypeInAssembly (Assembly invocation, Assembly assembly, string name)
 193                 {
 194                         if (assembly == null)
 195                                 throw new ArgumentNullException ("assembly");
 196                         if (name == null)
 197                                 throw new ArgumentNullException ("name");
 198                         Type t = assembly.GetType (name);
 199                         if (t == null)
 200                                 return null;
 201
 202                         if (t.IsPointer)
 203                                 throw new InternalErrorException ("Use GetPointerType() to get a pointer");
 204
 205                         TypeAttributes ta = t.Attributes & TypeAttributes.VisibilityMask;
 206                         if (ta == TypeAttributes.NestedPrivate)
 207                                 return null;
 208
 209                         if ((ta == TypeAttributes.NotPublic ||
 210                              ta == TypeAttributes.NestedAssembly ||
 211                              ta == TypeAttributes.NestedFamANDAssem) &&
 212                             !TypeManager.IsThisOrFriendAssembly (invocation, t.Assembly))
 213                                 return null;
 214
 215                         return t;
 216                 }
 217
 218                 public override string ToString ()
 219                 {
 220                         return String.Format ("RootNamespace ({0}::)", alias_name);
 221                 }
 222
 223                 public override string GetSignatureForError ()
 224                 {
 225                         return alias_name + "::";
 226                 }
 227         }
 228
 229         public class GlobalRootNamespace : RootNamespace {
 230                 Module [] modules;
 231                 ListDictionary root_namespaces;
 232
 233                 public static GlobalRootNamespace Instance = new GlobalRootNamespace ();
 234
 235                 GlobalRootNamespace ()
 236                         : base ("global")
 237                 {
 238                         root_namespaces = new ListDictionary ();
 239                         root_namespaces.Add (alias_name, this);
 240                 }
 241
 242                 public static void Reset ()
 243                 {
 244                         Instance = new GlobalRootNamespace ();
 245                 }
 246
 247                 public Assembly [] Assemblies {
 248                     get { return referenced_assemblies; }
 249                 }
 250
 251                 public Module [] Modules {
 252                         get { return modules; }
 253                 }
 254
 255                 public void AddModuleReference (Module m)
 256                 {
 257                         int top = modules != null ? modules.Length : 0;
 258                         Module [] n = new Module [top + 1];
 259                         if (modules != null)
 260                                 modules.CopyTo (n, 0);
 261                         n [top] = m;
 262                         modules = n;
 263
 264                         if (m == RootContext.ToplevelTypes.Builder)
 265                                 return;
 266
 267                         foreach (Type t in m.GetTypes ())
 268                                 RegisterNamespace (t.Namespace);
 269                 }
 270
 271                 public void ComputeNamespaces (CompilerContext ctx)
 272                 {
 273                         //
 274                         // Do very early lookup because type is required when we cache
 275                         // imported extension types in ComputeNamespaces
 276                         //
 277                         Type extension_attribute_type = TypeManager.CoreLookupType (ctx, "System.Runtime.CompilerServices", "ExtensionAttribute", Kind.Class, false);
 278
 279                         foreach (RootNamespace rn in root_namespaces.Values) {
 280                                 rn.ComputeNamespace (ctx, extension_attribute_type);
 281                         }
 282                 }
 283
 284                 public void DefineRootNamespace (string alias, Assembly assembly, CompilerContext ctx)
 285                 {
 286                         if (alias == alias_name) {
 287                                 NamespaceEntry.Error_GlobalNamespaceRedefined (Location.Null, ctx.Report);
 288                                 return;
 289                         }
 290
 291                         RootNamespace retval = GetRootNamespace (alias);
 292                         if (retval == null) {
 293                                 retval = new RootNamespace (alias);
 294                                 root_namespaces.Add (alias, retval);
 295                         }
 296
 297                         retval.AddAssemblyReference (assembly);
 298                 }
 299
 300                 public override void Error_NamespaceDoesNotExist (Location loc, string name, Report Report)
 301                 {
 302                         Report.Error (400, loc, "The type or namespace name `{0}' could not be found in the global namespace (are you missing an assembly reference?)",
 303                                 name);
 304                 }
 305
 306                 public RootNamespace GetRootNamespace (string name)
 307                 {
 308                         return (RootNamespace) root_namespaces[name];
 309                 }
 310
 311                 public override Type LookupTypeReflection (CompilerContext ctx, string name, Location loc, bool must_be_unique)
 312                 {
 313                         Type found_type = base.LookupTypeReflection (ctx, name, loc, must_be_unique);
 314
 315                         if (modules != null) {
 316                                 foreach (Module module in modules) {
 317                                         Type t = module.GetType (name);
 318                                         if (t == null)
 319                                                 continue;
 320
 321                                         if (found_type == null) {
 322                                                 found_type = t;
 323                                                 continue;
 324                                         }
 325
 326                                         ctx.Report.SymbolRelatedToPreviousError (found_type);
 327                                         if (loc.IsNull) {
 328                                                 DeclSpace ds = TypeManager.LookupDeclSpace (t);
 329                                                 Error_AmbiguousPredefinedType (ctx, ds.Location, name, found_type);
 330                                                 return found_type;
 331                                         }
 332                                         ctx.Report.SymbolRelatedToPreviousError (t);
 333                                         ctx.Report.Warning (436, 2, loc, "The type `{0}' conflicts with the imported type `{1}'. Ignoring the imported type definition",
 334                                                 TypeManager.CSharpName (t), TypeManager.CSharpName (found_type));
 335                                         return t;
 336                                 }
 337                         }
 338
 339                         return found_type;
 340                 }
 341         }
 342
 343         /// <summary>
 344         ///   Keeps track of the namespaces defined in the C# code.
 345         ///
 346         ///   This is an Expression to allow it to be referenced in the
 347         ///   compiler parse/intermediate tree during name resolution.
 348         /// </summary>
 349         public class Namespace : FullNamedExpression {
 350
 351                 Namespace parent;
 352                 string fullname;
 353                 IDictionary namespaces;
 354                 IDictionary declspaces;
 355                 Hashtable cached_types;
 356                 RootNamespace root;
 357                 ArrayList external_exmethod_classes;
 358
 359                 public readonly MemberName MemberName;
 360
 361                 /// <summary>
 362                 ///   Constructor Takes the current namespace and the
 363                 ///   name.  This is bootstrapped with parent == null
 364                 ///   and name = ""
 365                 /// </summary>
 366                 public Namespace (Namespace parent, string name)
 367                 {
 368                         // Expression members.
 369                         this.eclass = ExprClass.Namespace;
 370                         this.Type = typeof (Namespace);
 371                         this.loc = Location.Null;
 372
 373                         this.parent = parent;
 374
 375                         if (parent != null)
 376                                 this.root = parent.root;
 377                         else
 378                                 this.root = this as RootNamespace;
 379
 380                         if (this.root == null)
 381                                 throw new InternalErrorException ("Root namespaces must be created using RootNamespace");
 382
 383                         string pname = parent != null ? parent.fullname : "";
 384
 385                         if (pname == "")
 386                                 fullname = name;
 387                         else
 388                                 fullname = parent.fullname + "." + name;
 389
 390                         if (fullname == null)
 391                                 throw new InternalErrorException ("Namespace has a null fullname");
 392
 393                         if (parent != null && parent.MemberName != MemberName.Null)
 394                                 MemberName = new MemberName (parent.MemberName, name);
 395                         else if (name.Length == 0)
 396                                 MemberName = MemberName.Null;
 397                         else
 398                                 MemberName = new MemberName (name);
 399
 400                         namespaces = new HybridDictionary ();
 401                         cached_types = new Hashtable ();
 402
 403                         root.RegisterNamespace (this);
 404                 }
 405
 406                 public override Expression DoResolve (ResolveContext ec)
 407                 {
 408                         return this;
 409                 }
 410
 411                 public virtual void Error_NamespaceDoesNotExist (Location loc, string name, Report Report)
 412                 {
 413                         if (name.IndexOf ('`') > 0) {
 414                                 FullNamedExpression retval = Lookup (RootContext.ToplevelTypes.Compiler, SimpleName.RemoveGenericArity (name), loc);
 415                                 if (retval != null) {
 416                                         retval.Error_TypeArgumentsCannotBeUsed (Report, loc);
 417                                         return;
 418                                 }
 419                         } else {
 420                                 Type t = LookForAnyGenericType (name);
 421                                 if (t != null) {
 422                                         Error_InvalidNumberOfTypeArguments (t, loc);
 423                                         return;
 424                                 }
 425                         }
 426
 427                         Report.Error (234, loc, "The type or namespace name `{0}' does not exist in the namespace `{1}'. Are you missing an assembly reference?",
 428                                 name, GetSignatureForError ());
 429                 }
 430
 431                 public static void Error_InvalidNumberOfTypeArguments (Type t, Location loc)
 432                 {
 433                         RootContext.ToplevelTypes.Compiler.Report.SymbolRelatedToPreviousError (t);
 434                         RootContext.ToplevelTypes.Compiler.Report.Error (305, loc, "Using the generic type `{0}' requires `{1}' type argument(s)",
 435                                 TypeManager.CSharpName(t), TypeManager.GetNumberOfTypeArguments(t).ToString());
 436                 }
 437
 438                 public override string GetSignatureForError ()
 439                 {
 440                         return fullname;
 441                 }
 442
 443                 public Namespace GetNamespace (string name, bool create)
 444                 {
 445                         int pos = name.IndexOf ('.');
 446
 447                         Namespace ns;
 448                         string first;
 449                         if (pos >= 0)
 450                                 first = name.Substring (0, pos);
 451                         else
 452                                 first = name;
 453
 454                         ns = (Namespace) namespaces [first];
 455                         if (ns == null) {
 456                                 if (!create)
 457                                         return null;
 458
 459                                 ns = new Namespace (this, first);
 460                                 namespaces.Add (first, ns);
 461                         }
 462
 463                         if (pos >= 0)
 464                                 ns = ns.GetNamespace (name.Substring (pos + 1), create);
 465
 466                         return ns;
 467                 }
 468
 469                 public bool HasDefinition (string name)
 470                 {
 471                         return declspaces != null && declspaces [name] != null;
 472                 }
 473
 474                 TypeExpr LookupType (CompilerContext ctx, string name, Location loc)
 475                 {
 476                         if (cached_types.Contains (name))
 477                                 return cached_types [name] as TypeExpr;
 478
 479                         Type t = null;
 480                         if (declspaces != null) {
 481                                 DeclSpace tdecl = declspaces [name] as DeclSpace;
 482                                 if (tdecl != null) {
 483                                         //
 484                                         // Note that this is not:
 485                                         //
 486                                         //   t = tdecl.DefineType ()
 487                                         //
 488                                         // This is to make it somewhat more useful when a DefineType
 489                                         // fails due to problems in nested types (more useful in the sense
 490                                         // of fewer misleading error messages)
 491                                         //
 492                                         tdecl.DefineType ();
 493                                         t = tdecl.TypeBuilder;
 494
 495                                         if (RootContext.EvalMode){
 496                                                 // Replace the TypeBuilder with a System.Type, as
 497                                                 // Reflection.Emit fails otherwise (we end up pretty
 498                                                 // much with Random type definitions later on).
 499                                                 Type tt = t.Assembly.GetType (t.Name);
 500                                                 if (tt != null)
 501                                                         t = tt;
 502                                         }
 503                                 }
 504                         }
 505                         string lookup = t != null ? t.FullName : (fullname.Length == 0 ? name : fullname + "." + name);
 506                         Type rt = root.LookupTypeReflection (ctx, lookup, loc, t == null);
 507
 508                         // HACK: loc.IsNull when the type is core type
 509                         if (t == null || (rt != null && loc.IsNull))
 510                                 t = rt;
 511
 512                         TypeExpr te = t == null ? null : new TypeExpression (t, Location.Null);
 513                         cached_types [name] = te;
 514                         return te;
 515                 }
 516
 517                 ///
 518                 /// Used for better error reporting only
 519                 ///
 520                 public Type LookForAnyGenericType (string typeName)
 521                 {
 522                         if (declspaces == null)
 523                                 return null;
 524
 525                         typeName = SimpleName.RemoveGenericArity (typeName);
 526
 527                         foreach (DictionaryEntry de in declspaces) {
 528                                 string type_item = (string) de.Key;
 529                                 int pos = type_item.LastIndexOf ('`');
 530                                 if (pos == typeName.Length && String.Compare (typeName, 0, type_item, 0, pos) == 0)
 531                                         return ((DeclSpace) de.Value).TypeBuilder;
 532                         }
 533                         return null;
 534                 }
 535
 536                 public FullNamedExpression Lookup (CompilerContext ctx, string name, Location loc)
 537                 {
 538                         if (namespaces.Contains (name))
 539                                 return (Namespace) namespaces [name];
 540
 541                         return LookupType (ctx, name, loc);
 542                 }
 543
 544                 //
 545                 // Completes types with the given `prefix' and stores the results in `result'
 546                 //
 547                 public void CompletionGetTypesStartingWith (string prefix, Hashtable result)
 548                 {
 549                         int l = fullname.Length + 1;
 550                         ICollection res = root.CompletionGetTypesStartingWith (fullname + "." + prefix);
 551
 552                         if (res == null)
 553                                 return;
 554
 555                         foreach (string match in res){
 556                                 string x = match.Substring (l);
 557
 558                                 // Turn reflection nested classes foo+bar into foo.bar
 559                                 x = x.Replace ('+', '.');
 560
 561                                 // Only get the first name element, no point in adding anything beyond the first dot.
 562                                 int p = x.IndexOf ('.');
 563                                 if (p != -1)
 564                                         x = x.Substring (0, p);
 565
 566                                 // Turn Foo`N into Foo<
 567                                 p = x.IndexOf ('`');
 568                                 if (p != -1)
 569                                         x = x.Substring (0, p) + "<";
 570
 571                                 if (!result.Contains (x))
 572                                         result [x] = x;
 573                         }
 574                 }
 575
 576                 public void RegisterExternalExtensionMethodClass (Type type)
 577                 {
 578                         // Ignore, extension methods cannot be nested
 579                         if (type.DeclaringType != null)
 580                                 return;
 581
 582                         // TODO: CodeGen.Assembly.Builder is global
 583                         if (type.IsNotPublic && !TypeManager.IsThisOrFriendAssembly (CodeGen.Assembly.Builder, type.Assembly))
 584                                 return;
 585
 586                         if (external_exmethod_classes == null)
 587                                 external_exmethod_classes = new ArrayList ();
 588
 589                         external_exmethod_classes.Add (type);
 590                 }
 591
 592                 ///
 593                 /// Looks for extension method in this namespace
 594                 ///
 595                 public ArrayList LookupExtensionMethod (Type extensionType, ClassOrStruct currentClass, string name)
 596                 {
 597                         ArrayList found = null;
 598
 599                         // TODO: problematic
 600                         var invocation_assembly = CodeGen.Assembly.Builder;
 601
 602                         if (declspaces != null) {
 603                                 IEnumerator e = declspaces.Values.GetEnumerator ();
 604                                 e.Reset ();
 605                                 while (e.MoveNext ()) {
 606                                         Class c = e.Current as Class;
 607                                         if (c == null)
 608                                                 continue;
 609
 610                                         if ((c.ModFlags & Modifiers.METHOD_EXTENSION) == 0)
 611                                                 continue;
 612
 613                                         ArrayList res = c.MemberCache.FindExtensionMethods (invocation_assembly, extensionType, name, c != currentClass);
 614                                         if (res == null)
 615                                                 continue;
 616
 617                                         if (found == null)
 618                                                 found = res;
 619                                         else
 620                                                 found.AddRange (res);
 621                                 }
 622                         }
 623
 624                         if (external_exmethod_classes == null)
 625                                 return found;
 626
 627                         foreach (Type t in external_exmethod_classes) {
 628                                 MemberCache m = TypeHandle.GetMemberCache (t);
 629                                 ArrayList res = m.FindExtensionMethods (invocation_assembly, extensionType, name, true);
 630                                 if (res == null)
 631                                         continue;
 632
 633                                 if (found == null)
 634                                         found = res;
 635                                 else
 636                                         found.AddRange (res);
 637                         }
 638
 639                         return found;
 640                 }
 641
 642                 public void AddDeclSpace (string name, DeclSpace ds)
 643                 {
 644                         if (declspaces == null)
 645                                 declspaces = new HybridDictionary ();
 646                         declspaces.Add (name, ds);
 647                 }
 648
 649                 public void RemoveDeclSpace (string name)
 650                 {
 651                         declspaces.Remove (name);
 652                 }
 653
 654                 /// <summary>
 655                 ///   The qualified name of the current namespace
 656                 /// </summary>
 657                 public string Name {
 658                         get { return fullname; }
 659                 }
 660
 661                 /// <summary>
 662                 ///   The parent of this namespace, used by the parser to "Pop"
 663                 ///   the current namespace declaration
 664                 /// </summary>
 665                 public Namespace Parent {
 666                         get { return parent; }
 667                 }
 668         }
 669
 670         //
 671         // Namespace container as created by the parser
 672         //
 673         public class NamespaceEntry : IMemberContext {
 674
 675                 class UsingEntry {
 676                         readonly MemberName name;
 677                         Namespace resolved;
 678
 679                         public UsingEntry (MemberName name)
 680                         {
 681                                 this.name = name;
 682                         }
 683
 684                         public string GetSignatureForError ()
 685                         {
 686                                 return name.GetSignatureForError ();
 687                         }
 688
 689                         public Location Location {
 690                                 get { return name.Location; }
 691                         }
 692
 693                         public MemberName MemberName {
 694                                 get { return name; }
 695                         }
 696
 697                         public string Name {
 698                                 get { return GetSignatureForError (); }
 699                         }
 700
 701                         public Namespace Resolve (IMemberContext rc)
 702                         {
 703                                 if (resolved != null)
 704                                         return resolved;
 705
 706                                 FullNamedExpression fne = name.GetTypeExpression ().ResolveAsTypeStep (rc, false);
 707                                 if (fne == null)
 708                                         return null;
 709
 710                                 resolved = fne as Namespace;
 711                                 if (resolved == null) {
 712                                         rc.Compiler.Report.SymbolRelatedToPreviousError (fne.Type);
 713                                         rc.Compiler.Report.Error (138, Location,
 714                                                 "`{0}' is a type not a namespace. A using namespace directive can only be applied to namespaces",
 715                                                 GetSignatureForError ());
 716                                 }
 717                                 return resolved;
 718                         }
 719
 720                         public override string ToString ()
 721                         {
 722                                 return Name;
 723                         }
 724                 }
 725
 726                 class UsingAliasEntry {
 727                         public readonly string Alias;
 728                         public Location Location;
 729
 730                         public UsingAliasEntry (string alias, Location loc)
 731                         {
 732                                 this.Alias = alias;
 733                                 this.Location = loc;
 734                         }
 735
 736                         public virtual FullNamedExpression Resolve (IMemberContext rc)
 737                         {
 738                                 FullNamedExpression fne = GlobalRootNamespace.Instance.GetRootNamespace (Alias);
 739                                 if (fne == null) {
 740                                         rc.Compiler.Report.Error (430, Location,
 741                                                 "The extern alias `{0}' was not specified in -reference option",
 742                                                 Alias);
 743                                 }
 744
 745                                 return fne;
 746                         }
 747
 748                         public override string ToString ()
 749                         {
 750                                 return Alias;
 751                         }
 752
 753                 }
 754
 755                 class LocalUsingAliasEntry : UsingAliasEntry {
 756                         FullNamedExpression resolved;
 757                         MemberName value;
 758
 759                         public LocalUsingAliasEntry (string alias, MemberName name, Location loc)
 760                                 : base (alias, loc)
 761                         {
 762                                 this.value = name;
 763                         }
 764
 765                         public override FullNamedExpression Resolve (IMemberContext rc)
 766                         {
 767                                 if (resolved != null || value == null)
 768                                         return resolved;
 769
 770                                 if (rc == null)
 771                                         return null;
 772
 773                                 resolved = value.GetTypeExpression ().ResolveAsTypeStep (rc, false);
 774                                 if (resolved == null) {
 775                                         value = null;
 776                                         return null;
 777                                 }
 778
 779                                 if (resolved is TypeExpr)
 780                                         resolved = resolved.ResolveAsBaseTerminal (rc, false);
 781
 782                                 return resolved;
 783                         }
 784
 785                         public override string ToString ()
 786                         {
 787                                 return String.Format ("{0} = {1}", Alias, value.GetSignatureForError ());
 788                         }
 789                 }
 790
 791                 Namespace ns;
 792                 NamespaceEntry parent, implicit_parent;
 793                 CompilationUnit file;
 794                 int symfile_id;
 795
 796                 // Namespace using import block
 797                 ArrayList using_aliases;
 798                 ArrayList using_clauses;
 799                 public bool DeclarationFound = false;
 800                 // End
 801
 802                 public readonly bool IsImplicit;
 803                 public readonly DeclSpace SlaveDeclSpace;
 804                 static readonly Namespace [] empty_namespaces = new Namespace [0];
 805                 Namespace [] namespace_using_table;
 806
 807                 static ArrayList entries = new ArrayList ();
 808
 809                 public static void Reset ()
 810                 {
 811                         entries = new ArrayList ();
 812                 }
 813
 814                 public NamespaceEntry (NamespaceEntry parent, CompilationUnit file, string name)
 815                 {
 816                         this.parent = parent;
 817                         this.file = file;
 818                         entries.Add (this);
 819
 820                         if (parent != null)
 821                                 ns = parent.NS.GetNamespace (name, true);
 822                         else if (name != null)
 823                                 ns = GlobalRootNamespace.Instance.GetNamespace (name, true);
 824                         else
 825                                 ns = GlobalRootNamespace.Instance;
 826                         SlaveDeclSpace = new RootDeclSpace (this);
 827                 }
 828
 829                 private NamespaceEntry (NamespaceEntry parent, CompilationUnit file, Namespace ns, bool slave)
 830                 {
 831                         this.parent = parent;
 832                         this.file = file;
 833                         this.IsImplicit = true;
 834                         this.ns = ns;
 835                         this.SlaveDeclSpace = slave ? new RootDeclSpace (this) : null;
 836                 }
 837
 838                 //
 839                 // Populates the Namespace with some using declarations, used by the
 840                 // eval mode.
 841                 //
 842                 public void Populate (ArrayList source_using_aliases, ArrayList source_using_clauses)
 843                 {
 844                         foreach (UsingAliasEntry uae in source_using_aliases){
 845                                 if (using_aliases == null)
 846                                         using_aliases = new ArrayList ();
 847
 848                                 using_aliases.Add (uae);
 849                         }
 850
 851                         foreach (UsingEntry ue in source_using_clauses){
 852                                 if (using_clauses == null)
 853                                         using_clauses = new ArrayList ();
 854
 855                                 using_clauses.Add (ue);
 856                         }
 857                 }
 858
 859                 //
 860                 // Extracts the using alises and using clauses into a couple of
 861                 // arrays that might already have the same information;  Used by the
 862                 // C# Eval mode.
 863                 //
 864                 public void Extract (ArrayList out_using_aliases, ArrayList out_using_clauses)
 865                 {
 866                         if (using_aliases != null){
 867                                 foreach (UsingAliasEntry uae in using_aliases){
 868                                         bool replaced = false;
 869
 870                                         for (int i = 0; i < out_using_aliases.Count; i++){
 871                                                 UsingAliasEntry out_uea = (UsingAliasEntry) out_using_aliases [i];
 872
 873                                                 if (out_uea.Alias == uae.Alias){
 874                                                         out_using_aliases [i] = uae;
 875                                                         replaced = true;
 876                                                         break;
 877                                                 }
 878                                         }
 879                                         if (!replaced)
 880                                                 out_using_aliases.Add (uae);
 881                                 }
 882                         }
 883
 884                         if (using_clauses != null){
 885                                 foreach (UsingEntry ue in using_clauses){
 886                                         bool found = false;
 887
 888                                         foreach (UsingEntry out_ue in out_using_clauses)
 889                                                 if (out_ue.Name == ue.Name){
 890                                                         found = true;
 891                                                         break;
 892                                                 }
 893                                         if (!found)
 894                                                 out_using_clauses.Add (ue);
 895                                 }
 896                         }
 897                 }
 898
 899                 //
 900                 // According to section 16.3.1 (using-alias-directive), the namespace-or-type-name is
 901                 // resolved as if the immediately containing namespace body has no using-directives.
 902                 //
 903                 // Section 16.3.2 says that the same rule is applied when resolving the namespace-name
 904                 // in the using-namespace-directive.
 905                 //
 906                 // To implement these rules, the expressions in the using directives are resolved using
 907                 // the "doppelganger" (ghostly bodiless duplicate).
 908                 //
 909                 NamespaceEntry doppelganger;
 910                 NamespaceEntry Doppelganger {
 911                         get {
 912                                 if (!IsImplicit && doppelganger == null) {
 913                                         doppelganger = new NamespaceEntry (ImplicitParent, file, ns, true);
 914                                         doppelganger.using_aliases = using_aliases;
 915                                 }
 916                                 return doppelganger;
 917                         }
 918                 }
 919
 920                 public Namespace NS {
 921                         get { return ns; }
 922                 }
 923
 924                 public NamespaceEntry Parent {
 925                         get { return parent; }
 926                 }
 927
 928                 public NamespaceEntry ImplicitParent {
 929                         get {
 930                                 if (parent == null)
 931                                         return null;
 932                                 if (implicit_parent == null) {
 933                                         implicit_parent = (parent.NS == ns.Parent)
 934                                                 ? parent
 935                                                 : new NamespaceEntry (parent, file, ns.Parent, false);
 936                                 }
 937                                 return implicit_parent;
 938                         }
 939                 }
 940
 941                 /// <summary>
 942                 ///   Records a new namespace for resolving name references
 943                 /// </summary>
 944                 public void AddUsing (MemberName name, Location loc)
 945                 {
 946                         if (DeclarationFound){
 947                                 Compiler.Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
 948                         }
 949
 950                         if (using_clauses == null) {
 951                                 using_clauses = new ArrayList ();
 952                         } else {
 953                                 foreach (UsingEntry old_entry in using_clauses) {
 954                                         if (name.Equals (old_entry.MemberName)) {
 955                                                 Compiler.Report.SymbolRelatedToPreviousError (old_entry.Location, old_entry.GetSignatureForError ());
 956                                                 Compiler.Report.Warning (105, 3, loc, "The using directive for `{0}' appeared previously in this namespace", name.GetSignatureForError ());
 957                                                 return;
 958                                         }
 959                                 }
 960                         }
 961
 962                         using_clauses.Add (new UsingEntry (name));
 963                 }
 964
 965                 public void AddUsingAlias (string alias, MemberName name, Location loc)
 966                 {
 967                         // TODO: This is parser bussines
 968                         if (DeclarationFound){
 969                                 Compiler.Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
 970                         }
 971
 972                         if (RootContext.Version != LanguageVersion.ISO_1 && alias == "global")
 973                                 Compiler.Report.Warning (440, 2, loc, "An alias named `global' will not be used when resolving 'global::';" +
 974                                         " the global namespace will be used instead");
 975
 976                         AddUsingAlias (new LocalUsingAliasEntry (alias, name, loc));
 977                 }
 978
 979                 public void AddUsingExternalAlias (string alias, Location loc, Report Report)
 980                 {
 981                         // TODO: Do this in parser
 982                         bool not_first = using_clauses != null || DeclarationFound;
 983                         if (using_aliases != null && !not_first) {
 984                                 foreach (UsingAliasEntry uae in using_aliases) {
 985                                         if (uae is LocalUsingAliasEntry) {
 986                                                 not_first = true;
 987                                                 break;
 988                                         }
 989                                 }
 990                         }
 991
 992                         if (not_first)
 993                                 Report.Error (439, loc, "An extern alias declaration must precede all other elements");
 994
 995                         if (alias == "global") {
 996                                 Error_GlobalNamespaceRedefined (loc, Report);
 997                                 return;
 998                         }
 999
1000                         AddUsingAlias (new UsingAliasEntry (alias, loc));
1001                 }
1002
1003                 void AddUsingAlias (UsingAliasEntry uae)
1004                 {
1005                         if (using_aliases == null) {
1006                                 using_aliases = new ArrayList ();
1007                         } else {
1008                                 foreach (UsingAliasEntry entry in using_aliases) {
1009                                         if (uae.Alias == entry.Alias) {
1010                                                 Compiler.Report.SymbolRelatedToPreviousError (uae.Location, uae.Alias);
1011                                                 Compiler.Report.Error (1537, entry.Location, "The using alias `{0}' appeared previously in this namespace",
1012                                                         entry.Alias);
1013                                                 return;
1014                                         }
1015                                 }
1016                         }
1017
1018                         using_aliases.Add (uae);
1019                 }
1020
1021                 ///
1022                 /// Does extension methods look up to find a method which matches name and extensionType.
1023                 /// Search starts from this namespace and continues hierarchically up to top level.
1024                 ///
1025                 public ExtensionMethodGroupExpr LookupExtensionMethod (Type extensionType, string name, Location loc)
1026                 {
1027                         ArrayList candidates = null;
1028                         foreach (Namespace n in GetUsingTable ()) {
1029                                 ArrayList a = n.LookupExtensionMethod (extensionType, null, name);
1030                                 if (a == null)
1031                                         continue;
1032
1033                                 if (candidates == null)
1034                                         candidates = a;
1035                                 else
1036                                         candidates.AddRange (a);
1037                         }
1038
1039                         if (candidates != null)
1040                                 return new ExtensionMethodGroupExpr (candidates, parent, extensionType, loc);
1041
1042                         if (parent == null)
1043                                 return null;
1044
1045                         //
1046                         // Inspect parent namespaces in namespace expression
1047                         //
1048                         Namespace parent_ns = ns.Parent;
1049                         do {
1050                                 candidates = parent_ns.LookupExtensionMethod (extensionType, null, name);
1051                                 if (candidates != null)
1052                                         return new ExtensionMethodGroupExpr (candidates, parent, extensionType, loc);
1053
1054                                 parent_ns = parent_ns.Parent;
1055                         } while (parent_ns != null);
1056
1057                         //
1058                         // Continue in parent scope
1059                         //
1060                         return parent.LookupExtensionMethod (extensionType, name, loc);
1061                 }
1062
1063                 public FullNamedExpression LookupNamespaceOrType (string name, Location loc, bool ignore_cs0104)
1064                 {
1065                         // Precondition: Only simple names (no dots) will be looked up with this function.
1066                         FullNamedExpression resolved = null;
1067                         for (NamespaceEntry curr_ns = this; curr_ns != null; curr_ns = curr_ns.ImplicitParent) {
1068                                 if ((resolved = curr_ns.Lookup (name, loc, ignore_cs0104)) != null)
1069                                         break;
1070                         }
1071                         return resolved;
1072                 }
1073
1074                 public ICollection CompletionGetTypesStartingWith (string prefix)
1075                 {
1076                         Hashtable result = new Hashtable ();
1077
1078                         for (NamespaceEntry curr_ns = this; curr_ns != null; curr_ns = curr_ns.ImplicitParent){
1079                                 foreach (Namespace using_ns in GetUsingTable ()){
1080                                         if (prefix.StartsWith (using_ns.Name)){
1081                                                 int ld = prefix.LastIndexOf ('.');
1082                                                 if (ld != -1){
1083                                                         string rest = prefix.Substring (ld+1);
1084
1085                                                         using_ns.CompletionGetTypesStartingWith (rest, result);
1086                                                 }
1087                                         }
1088                                         using_ns.CompletionGetTypesStartingWith (prefix, result);
1089                                 }
1090                         }
1091
1092                         return result.Keys;
1093                 }
1094
1095                 void Error_AmbiguousTypeReference (Location loc, string name, FullNamedExpression t1, FullNamedExpression t2)
1096                 {
1097                         Compiler.Report.SymbolRelatedToPreviousError (t1.Type);
1098                         Compiler.Report.SymbolRelatedToPreviousError (t2.Type);
1099                         Compiler.Report.Error (104, loc, "`{0}' is an ambiguous reference between `{1}' and `{2}'",
1100                                 name, t1.GetSignatureForError (), t2.GetSignatureForError ());
1101                 }
1102
1103                 // Looks-up a alias named @name in this and surrounding namespace declarations
1104                 public FullNamedExpression LookupNamespaceAlias (string name)
1105                 {
1106                         for (NamespaceEntry n = this; n != null; n = n.ImplicitParent) {
1107                                 if (n.using_aliases == null)
1108                                         continue;
1109
1110                                 foreach (UsingAliasEntry ue in n.using_aliases) {
1111                                         if (ue.Alias == name)
1112                                                 return ue.Resolve (Doppelganger);
1113                                 }
1114                         }
1115
1116                         return null;
1117                 }
1118
1119                 private FullNamedExpression Lookup (string name, Location loc, bool ignore_cs0104)
1120                 {
1121                         //
1122                         // Check whether it's in the namespace.
1123                         //
1124                         FullNamedExpression fne = ns.Lookup (Compiler, name, loc);
1125
1126                         //
1127                         // Check aliases.
1128                         //
1129                         if (using_aliases != null) {
1130                                 foreach (UsingAliasEntry ue in using_aliases) {
1131                                         if (ue.Alias == name) {
1132                                                 if (fne != null) {
1133                                                         if (Doppelganger != null) {
1134                                                                 // TODO: Namespace has broken location
1135                                                                 //Report.SymbolRelatedToPreviousError (fne.Location, null);
1136                                                                 Compiler.Report.SymbolRelatedToPreviousError (ue.Location, null);
1137                                                                 Compiler.Report.Error (576, loc,
1138                                                                         "Namespace `{0}' contains a definition with same name as alias `{1}'",
1139                                                                         GetSignatureForError (), name);
1140                                                         } else {
1141                                                                 return fne;
1142                                                         }
1143                                                 }
1144
1145                                                 return ue.Resolve (Doppelganger);
1146                                         }
1147                                 }
1148                         }
1149
1150                         if (fne != null)
1151                                 return fne;
1152
1153                         if (IsImplicit)
1154                                 return null;
1155
1156                         //
1157                         // Check using entries.
1158                         //
1159                         FullNamedExpression match = null;
1160                         foreach (Namespace using_ns in GetUsingTable ()) {
1161                                 match = using_ns.Lookup (Compiler, name, loc);
1162                                 if (match == null || !(match is TypeExpr))
1163                                         continue;
1164                                 if (fne != null) {
1165                                         if (!ignore_cs0104)
1166                                                 Error_AmbiguousTypeReference (loc, name, fne, match);
1167                                         return null;
1168                                 }
1169                                 fne = match;
1170                         }
1171
1172                         return fne;
1173                 }
1174
1175                 Namespace [] GetUsingTable ()
1176                 {
1177                         if (namespace_using_table != null)
1178                                 return namespace_using_table;
1179
1180                         if (using_clauses == null) {
1181                                 namespace_using_table = empty_namespaces;
1182                                 return namespace_using_table;
1183                         }
1184
1185                         ArrayList list = new ArrayList (using_clauses.Count);
1186
1187                         foreach (UsingEntry ue in using_clauses) {
1188                                 Namespace using_ns = ue.Resolve (Doppelganger);
1189                                 if (using_ns == null)
1190                                         continue;
1191
1192                                 list.Add (using_ns);
1193                         }
1194
1195                         namespace_using_table = (Namespace[])list.ToArray (typeof (Namespace));
1196                         return namespace_using_table;
1197                 }
1198
1199                 static readonly string [] empty_using_list = new string [0];
1200
1201                 public int SymbolFileID {
1202                         get {
1203                                 if (symfile_id == 0 && file.SourceFileEntry != null) {
1204                                         int parent_id = parent == null ? 0 : parent.SymbolFileID;
1205
1206                                         string [] using_list = empty_using_list;
1207                                         if (using_clauses != null) {
1208                                                 using_list = new string [using_clauses.Count];
1209                                                 for (int i = 0; i < using_clauses.Count; i++)
1210                                                         using_list [i] = ((UsingEntry) using_clauses [i]).MemberName.GetName ();
1211                                         }
1212
1213                                         symfile_id = SymbolWriter.DefineNamespace (ns.Name, file.CompileUnitEntry, using_list, parent_id);
1214                                 }
1215                                 return symfile_id;
1216                         }
1217                 }
1218
1219                 static void MsgtryRef (string s)
1220                 {
1221                         Console.WriteLine ("    Try using -r:" + s);
1222                 }
1223
1224                 static void MsgtryPkg (string s)
1225                 {
1226                         Console.WriteLine ("    Try using -pkg:" + s);
1227                 }
1228
1229                 public static void Error_GlobalNamespaceRedefined (Location loc, Report Report)
1230                 {
1231                         Report.Error (1681, loc, "You cannot redefine the global extern alias");
1232                 }
1233
1234                 public static void Error_NamespaceNotFound (Location loc, string name, Report Report)
1235                 {
1236                         Report.Error (246, loc, "The type or namespace name `{0}' could not be found. Are you missing a using directive or an assembly reference?",
1237                                 name);
1238
1239                         switch (name) {
1240                         case "Gtk": case "GtkSharp":
1241                                 MsgtryPkg ("gtk-sharp");
1242                                 break;
1243
1244                         case "Gdk": case "GdkSharp":
1245                                 MsgtryPkg ("gdk-sharp");
1246                                 break;
1247
1248                         case "Glade": case "GladeSharp":
1249                                 MsgtryPkg ("glade-sharp");
1250                                 break;
1251
1252                         case "System.Drawing":
1253                         case "System.Web.Services":
1254                         case "System.Web":
1255                         case "System.Data":
1256                         case "System.Windows.Forms":
1257                                 MsgtryRef (name);
1258                                 break;
1259                         }
1260                 }
1261
1262                 /// <summary>
1263                 ///   Used to validate that all the using clauses are correct
1264                 ///   after we are finished parsing all the files.
1265                 /// </summary>
1266                 void VerifyUsing ()
1267                 {
1268                         if (using_aliases != null) {
1269                                 foreach (UsingAliasEntry ue in using_aliases)
1270                                         ue.Resolve (Doppelganger);
1271                         }
1272
1273                         if (using_clauses != null) {
1274                                 foreach (UsingEntry ue in using_clauses)
1275                                         ue.Resolve (Doppelganger);
1276                         }
1277                 }
1278
1279                 /// <summary>
1280                 ///   Used to validate that all the using clauses are correct
1281                 ///   after we are finished parsing all the files.
1282                 /// </summary>
1283                 static public void VerifyAllUsing ()
1284                 {
1285                         foreach (NamespaceEntry entry in entries)
1286                                 entry.VerifyUsing ();
1287                 }
1288
1289                 public string GetSignatureForError ()
1290                 {
1291                         return ns.GetSignatureForError ();
1292                 }
1293
1294                 public override string ToString ()
1295                 {
1296                         return ns.ToString ();
1297                 }
1298
1299                 #region IMemberContext Members
1300
1301                 public CompilerContext Compiler {
1302                         get { return RootContext.ToplevelTypes.Compiler; }
1303                 }
1304
1305                 public Type CurrentType {
1306                         get { return SlaveDeclSpace.CurrentType; }
1307                 }
1308
1309                 public TypeContainer CurrentTypeDefinition {
1310                         get { return SlaveDeclSpace.CurrentTypeDefinition; }
1311                 }
1312
1313                 public TypeParameter[] CurrentTypeParameters {
1314                         get { return SlaveDeclSpace.CurrentTypeParameters; }
1315                 }
1316
1317                 public bool IsObsolete {
1318                         get { return SlaveDeclSpace.IsObsolete; }
1319                 }
1320
1321                 public bool IsUnsafe {
1322                         get { return SlaveDeclSpace.IsUnsafe; }
1323                 }
1324
1325                 public bool IsStatic {
1326                         get { return SlaveDeclSpace.IsStatic; }
1327                 }
1328
1329                 #endregion
1330         }
1331 }