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         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 (Type extensionType)
  61                 {
  62                         foreach (Assembly a in referenced_assemblies) {
  63                                 try {
  64                                         ComputeNamespaces (a, extensionType);
  65                                 } catch (TypeLoadException e) {
  66                                         Report.Error (11, Location.Null, e.Message);
  67                                 } catch (System.IO.FileNotFoundException) {
  68                                         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 (string name, Location loc, bool must_be_unique)
  75                 {
  76                         Type found_type = null;
  77
  78                         foreach (Assembly a in referenced_assemblies) {
  79                                 Type t = GetTypeInAssembly (a, name);
  80                                 if (t == null)
  81                                         continue;
  82
  83                                 if (!must_be_unique)
  84                                         return t;
  85
  86                                 if (found_type == null) {
  87                                         found_type = t;
  88                                         continue;
  89                                 }
  90
  91                                 // When type is forwarded
  92                                 if (t.Assembly == found_type.Assembly)
  93                                         continue;
  94
  95                                 Report.SymbolRelatedToPreviousError (found_type);
  96                                 Report.SymbolRelatedToPreviousError (t);
  97                                 if (loc.IsNull) {
  98                                         Error_AmbiguousPredefinedType (loc, name, found_type);
  99                                 } else {
 100                                         Report.Error (433, loc, "The imported type `{0}' is defined multiple times", name);
 101                                 }
 102
 103                                 return found_type;
 104                         }
 105
 106                         return found_type;
 107                 }
 108
 109                 //
 110                 // Returns the types starting with the given prefix
 111                 //
 112                 public ICollection CompletionGetTypesStartingWith (string prefix)
 113                 {
 114                         Hashtable result = null;
 115
 116                         foreach (Assembly a in referenced_assemblies){
 117                                 Type [] mtypes = a.GetTypes ();
 118
 119                                 foreach (Type t in mtypes){
 120                                         string f = t.FullName;
 121
 122                                         if (f.StartsWith (prefix) && (result == null || !result.Contains (f))){
 123                                                 if (result == null)
 124                                                         result = new Hashtable ();
 125
 126                                                 result [f] = f;
 127                                         }
 128                                 }
 129                         }
 130                         return result == null ? result : result.Keys;
 131                 }
 132
 133                 protected void Error_AmbiguousPredefinedType (Location loc, string name, Type type)
 134                 {
 135                         Report.Warning (1685, 1, loc,
 136                                 "The predefined type `{0}' is ambiguous. Using definition from `{1}'",
 137                                 name, type.Assembly.FullName);
 138                 }
 139
 140                 public void RegisterNamespace (Namespace child)
 141                 {
 142                         if (child != this)
 143                                 all_namespaces.Add (child.Name, child);
 144                 }
 145
 146                 public bool IsNamespace (string name)
 147                 {
 148                         return all_namespaces.Contains (name);
 149                 }
 150
 151                 protected void RegisterNamespace (string dotted_name)
 152                 {
 153                         if (dotted_name != null && dotted_name.Length != 0 && ! IsNamespace (dotted_name))
 154                                 GetNamespace (dotted_name, true);
 155                 }
 156
 157                 void RegisterExtensionMethodClass (Type t)
 158                 {
 159                         string n = t.Namespace;
 160                         Namespace ns = n == null ? GlobalRootNamespace.Instance : (Namespace) all_namespaces[n];
 161                         if (ns == null)
 162                                 ns = GetNamespace (n, true);
 163
 164                         ns.RegisterExternalExtensionMethodClass (t);
 165                 }
 166
 167                 void ComputeNamespaces (Assembly assembly, Type extensionType)
 168                 {
 169                         bool contains_extension_methods = extensionType != null && assembly.IsDefined (extensionType, false);
 170
 171                         if (get_namespaces_method != null) {
 172                                 string [] namespaces = (string []) get_namespaces_method.Invoke (assembly, null);
 173                                 foreach (string ns in namespaces)
 174                                         RegisterNamespace (ns);
 175
 176                                 if (!contains_extension_methods)
 177                                         return;
 178                         }
 179
 180                         foreach (Type t in assembly.GetTypes ()) {
 181                                 if ((t.Attributes & Class.StaticClassAttribute) == Class.StaticClassAttribute &&
 182                                         contains_extension_methods && t.IsDefined (extensionType, false))
 183                                         RegisterExtensionMethodClass (t);
 184
 185                                 if (get_namespaces_method == null)
 186                                         RegisterNamespace (t.Namespace);
 187                         }
 188                 }
 189
 190                 protected static Type GetTypeInAssembly (Assembly assembly, string name)
 191                 {
 192                         if (assembly == null)
 193                                 throw new ArgumentNullException ("assembly");
 194                         if (name == null)
 195                                 throw new ArgumentNullException ("name");
 196                         Type t = assembly.GetType (name);
 197                         if (t == null)
 198                                 return null;
 199
 200                         if (t.IsPointer)
 201                                 throw new InternalErrorException ("Use GetPointerType() to get a pointer");
 202
 203                         TypeAttributes ta = t.Attributes & TypeAttributes.VisibilityMask;
 204                         if (ta == TypeAttributes.NestedPrivate)
 205                                 return null;
 206
 207                         if ((ta == TypeAttributes.NotPublic ||
 208                              ta == TypeAttributes.NestedAssembly ||
 209                              ta == TypeAttributes.NestedFamANDAssem) &&
 210                             !TypeManager.IsThisOrFriendAssembly (t.Assembly))
 211                                 return null;
 212
 213                         return t;
 214                 }
 215
 216                 public override string ToString ()
 217                 {
 218                         return String.Format ("RootNamespace ({0}::)", alias_name);
 219                 }
 220
 221                 public override string GetSignatureForError ()
 222                 {
 223                         return alias_name + "::";
 224                 }
 225         }
 226
 227         class GlobalRootNamespace : RootNamespace {
 228                 Module [] modules;
 229                 ListDictionary root_namespaces;
 230
 231                 public static GlobalRootNamespace Instance = new GlobalRootNamespace ();
 232
 233                 GlobalRootNamespace ()
 234                         : base ("global")
 235                 {
 236                         root_namespaces = new ListDictionary ();
 237                         root_namespaces.Add (alias_name, this);
 238                 }
 239
 240                 public static void Reset ()
 241                 {
 242                         Instance = new GlobalRootNamespace ();
 243                 }
 244
 245                 public Assembly [] Assemblies {
 246                     get { return referenced_assemblies; }
 247                 }
 248
 249                 public Module [] Modules {
 250                         get { return modules; }
 251                 }
 252
 253                 public void AddModuleReference (Module m)
 254                 {
 255                         int top = modules != null ? modules.Length : 0;
 256                         Module [] n = new Module [top + 1];
 257                         if (modules != null)
 258                                 modules.CopyTo (n, 0);
 259                         n [top] = m;
 260                         modules = n;
 261
 262                         if (m == RootContext.ToplevelTypes.Builder)
 263                                 return;
 264
 265                         foreach (Type t in m.GetTypes ())
 266                                 RegisterNamespace (t.Namespace);
 267                 }
 268
 269                 public void ComputeNamespaces ()
 270                 {
 271                         //
 272                         // Do very early lookup because type is required when we cache
 273                         // imported extension types in ComputeNamespaces
 274                         //
 275                         Type extension_attribute_type = TypeManager.CoreLookupType ("System.Runtime.CompilerServices", "ExtensionAttribute", Kind.Class, false);
 276
 277                         foreach (RootNamespace rn in root_namespaces.Values) {
 278                                 rn.ComputeNamespace (extension_attribute_type);
 279                         }
 280                 }
 281
 282                 public void DefineRootNamespace (string alias, Assembly assembly)
 283                 {
 284                         if (alias == alias_name) {
 285                                 NamespaceEntry.Error_GlobalNamespaceRedefined (Location.Null);
 286                                 return;
 287                         }
 288
 289                         RootNamespace retval = GetRootNamespace (alias);
 290                         if (retval == null) {
 291                                 retval = new RootNamespace (alias);
 292                                 root_namespaces.Add (alias, retval);
 293                         }
 294
 295                         retval.AddAssemblyReference (assembly);
 296                 }
 297
 298                 public override void Error_NamespaceDoesNotExist(Location loc, string name)
 299                 {
 300                         Report.Error (400, loc, "The type or namespace name `{0}' could not be found in the global namespace (are you missing an assembly reference?)",
 301                                 name);
 302                 }
 303
 304                 public RootNamespace GetRootNamespace (string name)
 305                 {
 306                         return (RootNamespace) root_namespaces[name];
 307                 }
 308
 309                 public override Type LookupTypeReflection (string name, Location loc, bool must_be_unique)
 310                 {
 311                         Type found_type = base.LookupTypeReflection (name, loc, must_be_unique);
 312
 313                         if (modules != null) {
 314                                 foreach (Module module in modules) {
 315                                         Type t = module.GetType (name);
 316                                         if (t == null)
 317                                                 continue;
 318
 319                                         if (found_type == null) {
 320                                                 found_type = t;
 321                                                 continue;
 322                                         }
 323
 324                                         Report.SymbolRelatedToPreviousError (found_type);
 325                                         if (loc.IsNull) {
 326                                                 DeclSpace ds = TypeManager.LookupDeclSpace (t);
 327                                                 Error_AmbiguousPredefinedType (ds.Location, name, found_type);
 328                                                 return found_type;
 329                                         }
 330                                         Report.SymbolRelatedToPreviousError (t);
 331                                         Report.Warning (436, 2, loc, "The type `{0}' conflicts with the imported type `{1}'. Ignoring the imported type definition",
 332                                                 TypeManager.CSharpName (t), TypeManager.CSharpName (found_type));
 333                                         return t;
 334                                 }
 335                         }
 336
 337                         return found_type;
 338                 }
 339         }
 340
 341         /// <summary>
 342         ///   Keeps track of the namespaces defined in the C# code.
 343         ///
 344         ///   This is an Expression to allow it to be referenced in the
 345         ///   compiler parse/intermediate tree during name resolution.
 346         /// </summary>
 347         public class Namespace : FullNamedExpression {
 348
 349                 Namespace parent;
 350                 string fullname;
 351                 IDictionary namespaces;
 352                 IDictionary declspaces;
 353                 Hashtable cached_types;
 354                 RootNamespace root;
 355                 ArrayList external_exmethod_classes;
 356
 357                 public readonly MemberName MemberName;
 358
 359                 /// <summary>
 360                 ///   Constructor Takes the current namespace and the
 361                 ///   name.  This is bootstrapped with parent == null
 362                 ///   and name = ""
 363                 /// </summary>
 364                 public Namespace (Namespace parent, string name)
 365                 {
 366                         // Expression members.
 367                         this.eclass = ExprClass.Namespace;
 368                         this.Type = typeof (Namespace);
 369                         this.loc = Location.Null;
 370
 371                         this.parent = parent;
 372
 373                         if (parent != null)
 374                                 this.root = parent.root;
 375                         else
 376                                 this.root = this as RootNamespace;
 377
 378                         if (this.root == null)
 379                                 throw new InternalErrorException ("Root namespaces must be created using RootNamespace");
 380
 381                         string pname = parent != null ? parent.fullname : "";
 382
 383                         if (pname == "")
 384                                 fullname = name;
 385                         else
 386                                 fullname = parent.fullname + "." + name;
 387
 388                         if (fullname == null)
 389                                 throw new InternalErrorException ("Namespace has a null fullname");
 390
 391                         if (parent != null && parent.MemberName != MemberName.Null)
 392                                 MemberName = new MemberName (parent.MemberName, name);
 393                         else if (name.Length == 0)
 394                                 MemberName = MemberName.Null;
 395                         else
 396                                 MemberName = new MemberName (name);
 397
 398                         namespaces = new HybridDictionary ();
 399                         cached_types = new Hashtable ();
 400
 401                         root.RegisterNamespace (this);
 402                 }
 403
 404                 public override Expression DoResolve (EmitContext ec)
 405                 {
 406                         return this;
 407                 }
 408
 409                 public virtual void Error_NamespaceDoesNotExist (Location loc, string name)
 410                 {
 411                         if (name.IndexOf ('`') > 0) {
 412                                 FullNamedExpression retval = Lookup (SimpleName.RemoveGenericArity (name), loc);
 413                                 if (retval != null) {
 414                                         Error_TypeArgumentsCannotBeUsed (retval, loc);
 415                                         return;
 416                                 }
 417                         } else {
 418                                 Type t = LookForAnyGenericType (name);
 419                                 if (t != null) {
 420                                         Error_InvalidNumberOfTypeArguments (t, loc);
 421                                         return;
 422                                 }
 423                         }
 424
 425                         Report.Error (234, loc, "The type or namespace name `{0}' does not exist in the namespace `{1}'. Are you missing an assembly reference?",
 426                                 name, GetSignatureForError ());
 427                 }
 428
 429                 public static void Error_InvalidNumberOfTypeArguments (Type t, Location loc)
 430                 {
 431                         Report.SymbolRelatedToPreviousError (t);
 432                         Report.Error (305, loc, "Using the generic type `{0}' requires `{1}' type argument(s)",
 433                                 TypeManager.CSharpName(t), TypeManager.GetNumberOfTypeArguments(t).ToString());
 434                 }
 435
 436                 public static void Error_TypeArgumentsCannotBeUsed (FullNamedExpression expr, Location loc)
 437                 {
 438                         if (expr is TypeExpr) {
 439                                 Report.SymbolRelatedToPreviousError (expr.Type);
 440                                 Error_TypeArgumentsCannotBeUsed (loc, "type", expr.GetSignatureForError ());
 441                         } else {
 442                                 expr.Error_ExpressionCannotBeGeneric (loc);
 443                         }
 444                 }
 445
 446                 public static void Error_TypeArgumentsCannotBeUsed (MethodBase mi, Location loc)
 447                 {
 448                         Report.SymbolRelatedToPreviousError (mi);
 449                         Error_TypeArgumentsCannotBeUsed (loc, "method", TypeManager.CSharpSignature (mi));
 450                 }
 451
 452                 static void Error_TypeArgumentsCannotBeUsed (Location loc, string type, string name)
 453                 {
 454                         Report.Error(308, loc, "The non-generic {0} `{1}' cannot be used with the type arguments",
 455                                 type, name);
 456                 }
 457
 458                 public override string GetSignatureForError ()
 459                 {
 460                         return fullname;
 461                 }
 462
 463                 public Namespace GetNamespace (string name, bool create)
 464                 {
 465                         int pos = name.IndexOf ('.');
 466
 467                         Namespace ns;
 468                         string first;
 469                         if (pos >= 0)
 470                                 first = name.Substring (0, pos);
 471                         else
 472                                 first = name;
 473
 474                         ns = (Namespace) namespaces [first];
 475                         if (ns == null) {
 476                                 if (!create)
 477                                         return null;
 478
 479                                 ns = new Namespace (this, first);
 480                                 namespaces.Add (first, ns);
 481                         }
 482
 483                         if (pos >= 0)
 484                                 ns = ns.GetNamespace (name.Substring (pos + 1), create);
 485
 486                         return ns;
 487                 }
 488
 489                 public bool HasDefinition (string name)
 490                 {
 491                         return declspaces != null && declspaces [name] != null;
 492                 }
 493
 494                 TypeExpr LookupType (string name, Location loc)
 495                 {
 496                         if (cached_types.Contains (name))
 497                                 return cached_types [name] as TypeExpr;
 498
 499                         Type t = null;
 500                         if (declspaces != null) {
 501                                 DeclSpace tdecl = declspaces [name] as DeclSpace;
 502                                 if (tdecl != null) {
 503                                         //
 504                                         // Note that this is not:
 505                                         //
 506                                         //   t = tdecl.DefineType ()
 507                                         //
 508                                         // This is to make it somewhat more useful when a DefineType
 509                                         // fails due to problems in nested types (more useful in the sense
 510                                         // of fewer misleading error messages)
 511                                         //
 512                                         tdecl.DefineType ();
 513                                         t = tdecl.TypeBuilder;
 514
 515                                         if (RootContext.EvalMode){
 516                                                 // Replace the TypeBuilder with a System.Type, as
 517                                                 // Reflection.Emit fails otherwise (we end up pretty
 518                                                 // much with Random type definitions later on).
 519                                                 Type tt = t.Assembly.GetType (t.Name);
 520                                                 if (tt != null)
 521                                                         t = tt;
 522                                         }
 523                                 }
 524                         }
 525                         string lookup = t != null ? t.FullName : (fullname.Length == 0 ? name : fullname + "." + name);
 526                         Type rt = root.LookupTypeReflection (lookup, loc, t == null);
 527
 528                         // HACK: loc.IsNull when the type is core type
 529                         if (t == null || (rt != null && loc.IsNull))
 530                                 t = rt;
 531
 532                         TypeExpr te = t == null ? null : new TypeExpression (t, Location.Null);
 533                         cached_types [name] = te;
 534                         return te;
 535                 }
 536
 537                 ///
 538                 /// Used for better error reporting only
 539                 ///
 540                 public Type LookForAnyGenericType (string typeName)
 541                 {
 542                         if (declspaces == null)
 543                                 return null;
 544
 545                         typeName = SimpleName.RemoveGenericArity (typeName);
 546
 547                         foreach (DictionaryEntry de in declspaces) {
 548                                 string type_item = (string) de.Key;
 549                                 int pos = type_item.LastIndexOf ('`');
 550                                 if (pos == typeName.Length && String.Compare (typeName, 0, type_item, 0, pos) == 0)
 551                                         return ((DeclSpace) de.Value).TypeBuilder;
 552                         }
 553                         return null;
 554                 }
 555
 556                 public FullNamedExpression Lookup (string name, Location loc)
 557                 {
 558                         if (namespaces.Contains (name))
 559                                 return (Namespace) namespaces [name];
 560
 561                         return LookupType (name, loc);
 562                 }
 563
 564                 //
 565                 // Completes types with the given `prefix' and stores the results in `result'
 566                 //
 567                 public void CompletionGetTypesStartingWith (DeclSpace ds, string prefix, Hashtable result)
 568                 {
 569                         int l = fullname.Length + 1;
 570                         ICollection res = root.CompletionGetTypesStartingWith (fullname + "." + prefix);
 571
 572                         if (res == null)
 573                                 return;
 574
 575                         foreach (string match in res){
 576                                 string x = match.Substring (l);
 577
 578                                 // Turn reflection nested classes foo+bar into foo.bar
 579                                 x = x.Replace ('+', '.');
 580
 581                                 // Only get the first name element, no point in adding anything beyond the first dot.
 582                                 int p = x.IndexOf ('.');
 583                                 if (p != -1)
 584                                         x = x.Substring (0, p);
 585
 586                                 // Turn Foo`N into Foo<
 587                                 p = x.IndexOf ('`');
 588                                 if (p != -1)
 589                                         x = x.Substring (0, p) + "<";
 590
 591                                 if (!result.Contains (x))
 592                                         result [x] = x;
 593                         }
 594                 }
 595
 596                 public void RegisterExternalExtensionMethodClass (Type type)
 597                 {
 598                         // Ignore, extension methods cannot be nested
 599                         if (type.DeclaringType != null)
 600                                 return;
 601
 602                         if (type.IsNotPublic && !TypeManager.IsThisOrFriendAssembly (type.Assembly))
 603                                 return;
 604
 605                         if (external_exmethod_classes == null)
 606                                 external_exmethod_classes = new ArrayList ();
 607
 608                         external_exmethod_classes.Add (type);
 609                 }
 610
 611                 ///
 612                 /// Looks for extension method in this namespace
 613                 ///
 614                 public ArrayList LookupExtensionMethod (Type extensionType, ClassOrStruct currentClass, string name)
 615                 {
 616                         ArrayList found = null;
 617
 618                         if (declspaces != null) {
 619                                 IEnumerator e = declspaces.Values.GetEnumerator ();
 620                                 e.Reset ();
 621                                 while (e.MoveNext ()) {
 622                                         Class c = e.Current as Class;
 623                                         if (c == null)
 624                                                 continue;
 625
 626                                         if ((c.ModFlags & Modifiers.METHOD_EXTENSION) == 0)
 627                                                 continue;
 628
 629                                         ArrayList res = c.MemberCache.FindExtensionMethods (extensionType, name, c != currentClass);
 630                                         if (res == null)
 631                                                 continue;
 632
 633                                         if (found == null)
 634                                                 found = res;
 635                                         else
 636                                                 found.AddRange (res);
 637                                 }
 638                         }
 639
 640                         if (external_exmethod_classes == null)
 641                                 return found;
 642
 643                         foreach (Type t in external_exmethod_classes) {
 644                                 MemberCache m = TypeHandle.GetMemberCache (t);
 645                                 ArrayList res = m.FindExtensionMethods (extensionType, name, true);
 646                                 if (res == null)
 647                                         continue;
 648
 649                                 if (found == null)
 650                                         found = res;
 651                                 else
 652                                         found.AddRange (res);
 653                         }
 654
 655                         return found;
 656                 }
 657
 658                 public void AddDeclSpace (string name, DeclSpace ds)
 659                 {
 660                         if (declspaces == null)
 661                                 declspaces = new HybridDictionary ();
 662                         declspaces.Add (name, ds);
 663                 }
 664
 665                 public void RemoveDeclSpace (string name)
 666                 {
 667                         declspaces.Remove (name);
 668                 }
 669
 670                 /// <summary>
 671                 ///   The qualified name of the current namespace
 672                 /// </summary>
 673                 public string Name {
 674                         get { return fullname; }
 675                 }
 676
 677                 /// <summary>
 678                 ///   The parent of this namespace, used by the parser to "Pop"
 679                 ///   the current namespace declaration
 680                 /// </summary>
 681                 public Namespace Parent {
 682                         get { return parent; }
 683                 }
 684         }
 685
 686         //
 687         // Namespace container as created by the parser
 688         //
 689         public class NamespaceEntry : IResolveContext {
 690
 691                 class UsingEntry {
 692                         readonly MemberName name;
 693                         Namespace resolved;
 694
 695                         public UsingEntry (MemberName name)
 696                         {
 697                                 this.name = name;
 698                         }
 699
 700                         public string GetSignatureForError ()
 701                         {
 702                                 return name.GetSignatureForError ();
 703                         }
 704
 705                         public Location Location {
 706                                 get { return name.Location; }
 707                         }
 708
 709                         public MemberName MemberName {
 710                                 get { return name; }
 711                         }
 712
 713                         public string Name {
 714                                 get { return GetSignatureForError (); }
 715                         }
 716
 717                         public Namespace Resolve (IResolveContext rc)
 718                         {
 719                                 if (resolved != null)
 720                                         return resolved;
 721
 722                                 FullNamedExpression fne = name.GetTypeExpression ().ResolveAsTypeStep (rc, false);
 723                                 if (fne == null)
 724                                         return null;
 725
 726                                 resolved = fne as Namespace;
 727                                 if (resolved == null) {
 728                                         Report.SymbolRelatedToPreviousError (fne.Type);
 729                                         Report.Error (138, Location,
 730                                                 "`{0}' is a type not a namespace. A using namespace directive can only be applied to namespaces",
 731                                                 GetSignatureForError ());
 732                                 }
 733                                 return resolved;
 734                         }
 735
 736                         public override string ToString ()
 737                         {
 738                                 return Name;
 739                         }
 740                 }
 741
 742                 class UsingAliasEntry {
 743                         public readonly string Alias;
 744                         public Location Location;
 745
 746                         public UsingAliasEntry (string alias, Location loc)
 747                         {
 748                                 this.Alias = alias;
 749                                 this.Location = loc;
 750                         }
 751
 752                         public virtual FullNamedExpression Resolve (IResolveContext rc)
 753                         {
 754                                 FullNamedExpression fne = GlobalRootNamespace.Instance.GetRootNamespace (Alias);
 755                                 if (fne == null) {
 756                                         Report.Error (430, Location,
 757                                                 "The extern alias `{0}' was not specified in -reference option",
 758                                                 Alias);
 759                                 }
 760
 761                                 return fne;
 762                         }
 763
 764                         public override string ToString ()
 765                         {
 766                                 return Alias;
 767                         }
 768
 769                 }
 770
 771                 class LocalUsingAliasEntry : UsingAliasEntry {
 772                         FullNamedExpression resolved;
 773                         MemberName value;
 774
 775                         public LocalUsingAliasEntry (string alias, MemberName name, Location loc)
 776                                 : base (alias, loc)
 777                         {
 778                                 this.value = name;
 779                         }
 780
 781                         public override FullNamedExpression Resolve (IResolveContext rc)
 782                         {
 783                                 if (resolved != null || value == null)
 784                                         return resolved;
 785
 786                                 resolved = value.GetTypeExpression ().ResolveAsTypeStep (rc, false);
 787                                 if (resolved == null) {
 788                                         value = null;
 789                                         return null;
 790                                 }
 791
 792                                 if (resolved is TypeExpr)
 793                                         resolved = resolved.ResolveAsBaseTerminal (rc, false);
 794
 795                                 return resolved;
 796                         }
 797
 798                         public override string ToString ()
 799                         {
 800                                 return String.Format ("{0} = {1}", Alias, value.GetSignatureForError ());
 801                         }
 802                 }
 803
 804                 Namespace ns;
 805                 NamespaceEntry parent, implicit_parent;
 806                 CompilationUnit file;
 807                 int symfile_id;
 808
 809                 // Namespace using import block
 810                 ArrayList using_aliases;
 811                 ArrayList using_clauses;
 812                 public bool DeclarationFound = false;
 813                 // End
 814
 815                 public readonly bool IsImplicit;
 816                 public readonly DeclSpace SlaveDeclSpace;
 817                 static readonly Namespace [] empty_namespaces = new Namespace [0];
 818                 Namespace [] namespace_using_table;
 819
 820                 static ArrayList entries = new ArrayList ();
 821
 822                 public static void Reset ()
 823                 {
 824                         entries = new ArrayList ();
 825                 }
 826
 827                 public NamespaceEntry (NamespaceEntry parent, CompilationUnit file, string name)
 828                 {
 829                         this.parent = parent;
 830                         this.file = file;
 831                         entries.Add (this);
 832
 833                         if (parent != null)
 834                                 ns = parent.NS.GetNamespace (name, true);
 835                         else if (name != null)
 836                                 ns = GlobalRootNamespace.Instance.GetNamespace (name, true);
 837                         else
 838                                 ns = GlobalRootNamespace.Instance;
 839                         SlaveDeclSpace = new RootDeclSpace (this);
 840                 }
 841
 842                 private NamespaceEntry (NamespaceEntry parent, CompilationUnit file, Namespace ns, bool slave)
 843                 {
 844                         this.parent = parent;
 845                         this.file = file;
 846                         this.IsImplicit = true;
 847                         this.ns = ns;
 848                         this.SlaveDeclSpace = slave ? new RootDeclSpace (this) : null;
 849                 }
 850
 851                 //
 852                 // Populates the Namespace with some using declarations, used by the
 853                 // eval mode.
 854                 //
 855                 public void Populate (ArrayList source_using_aliases, ArrayList source_using_clauses)
 856                 {
 857                         foreach (UsingAliasEntry uae in source_using_aliases){
 858                                 if (using_aliases == null)
 859                                         using_aliases = new ArrayList ();
 860
 861                                 using_aliases.Add (uae);
 862                         }
 863
 864                         foreach (UsingEntry ue in source_using_clauses){
 865                                 if (using_clauses == null)
 866                                         using_clauses = new ArrayList ();
 867
 868                                 using_clauses.Add (ue);
 869                         }
 870                 }
 871
 872                 //
 873                 // Extracts the using alises and using clauses into a couple of
 874                 // arrays that might already have the same information;  Used by the
 875                 // C# Eval mode.
 876                 //
 877                 public void Extract (ArrayList out_using_aliases, ArrayList out_using_clauses)
 878                 {
 879                         if (using_aliases != null){
 880                                 foreach (UsingAliasEntry uae in using_aliases){
 881                                         bool replaced = false;
 882
 883                                         for (int i = 0; i < out_using_aliases.Count; i++){
 884                                                 UsingAliasEntry out_uea = (UsingAliasEntry) out_using_aliases [i];
 885
 886                                                 if (out_uea.Alias == uae.Alias){
 887                                                         out_using_aliases [i] = uae;
 888                                                         replaced = true;
 889                                                         break;
 890                                                 }
 891                                         }
 892                                         if (!replaced)
 893                                                 out_using_aliases.Add (uae);
 894                                 }
 895                         }
 896
 897                         if (using_clauses != null){
 898                                 foreach (UsingEntry ue in using_clauses){
 899                                         bool found = false;
 900
 901                                         foreach (UsingEntry out_ue in out_using_clauses)
 902                                                 if (out_ue.Name == ue.Name){
 903                                                         found = true;
 904                                                         break;
 905                                                 }
 906                                         if (!found)
 907                                                 out_using_clauses.Add (ue);
 908                                 }
 909                         }
 910                 }
 911
 912                 //
 913                 // According to section 16.3.1 (using-alias-directive), the namespace-or-type-name is
 914                 // resolved as if the immediately containing namespace body has no using-directives.
 915                 //
 916                 // Section 16.3.2 says that the same rule is applied when resolving the namespace-name
 917                 // in the using-namespace-directive.
 918                 //
 919                 // To implement these rules, the expressions in the using directives are resolved using
 920                 // the "doppelganger" (ghostly bodiless duplicate).
 921                 //
 922                 NamespaceEntry doppelganger;
 923                 NamespaceEntry Doppelganger {
 924                         get {
 925                                 if (!IsImplicit && doppelganger == null) {
 926                                         doppelganger = new NamespaceEntry (ImplicitParent, file, ns, true);
 927                                         doppelganger.using_aliases = using_aliases;
 928                                 }
 929                                 return doppelganger;
 930                         }
 931                 }
 932
 933                 public Namespace NS {
 934                         get { return ns; }
 935                 }
 936
 937                 public NamespaceEntry Parent {
 938                         get { return parent; }
 939                 }
 940
 941                 public NamespaceEntry ImplicitParent {
 942                         get {
 943                                 if (parent == null)
 944                                         return null;
 945                                 if (implicit_parent == null) {
 946                                         implicit_parent = (parent.NS == ns.Parent)
 947                                                 ? parent
 948                                                 : new NamespaceEntry (parent, file, ns.Parent, false);
 949                                 }
 950                                 return implicit_parent;
 951                         }
 952                 }
 953
 954                 /// <summary>
 955                 ///   Records a new namespace for resolving name references
 956                 /// </summary>
 957                 public void AddUsing (MemberName name, Location loc)
 958                 {
 959                         if (DeclarationFound){
 960                                 Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
 961                         }
 962
 963                         if (using_clauses == null) {
 964                                 using_clauses = new ArrayList ();
 965                         } else {
 966                                 foreach (UsingEntry old_entry in using_clauses) {
 967                                         if (name.Equals (old_entry.MemberName)) {
 968                                                 Report.SymbolRelatedToPreviousError (old_entry.Location, old_entry.GetSignatureForError ());
 969                                                 Report.Warning (105, 3, loc, "The using directive for `{0}' appeared previously in this namespace", name.GetSignatureForError ());
 970                                                 return;
 971                                         }
 972                                 }
 973                         }
 974
 975                         using_clauses.Add (new UsingEntry (name));
 976                 }
 977
 978                 public void AddUsingAlias (string alias, MemberName name, Location loc)
 979                 {
 980                         // TODO: This is parser bussines
 981                         if (DeclarationFound){
 982                                 Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
 983                         }
 984
 985                         if (RootContext.Version != LanguageVersion.ISO_1 && alias == "global")
 986                                 Report.Warning (440, 2, loc, "An alias named `global' will not be used when resolving 'global::';" +
 987                                         " the global namespace will be used instead");
 988
 989                         AddUsingAlias (new LocalUsingAliasEntry (alias, name, loc));
 990                 }
 991
 992                 public void AddUsingExternalAlias (string alias, Location loc)
 993                 {
 994                         // TODO: Do this in parser
 995                         bool not_first = using_clauses != null || DeclarationFound;
 996                         if (using_aliases != null && !not_first) {
 997                                 foreach (UsingAliasEntry uae in using_aliases) {
 998                                         if (uae is LocalUsingAliasEntry) {
 999                                                 not_first = true;
1000                                                 break;
1001                                         }
1002                                 }
1003                         }
1004
1005                         if (not_first)
1006                                 Report.Error (439, loc, "An extern alias declaration must precede all other elements");
1007
1008                         if (alias == "global") {
1009                                 Error_GlobalNamespaceRedefined (loc);
1010                                 return;
1011                         }
1012
1013                         AddUsingAlias (new UsingAliasEntry (alias, loc));
1014                 }
1015
1016                 void AddUsingAlias (UsingAliasEntry uae)
1017                 {
1018                         if (using_aliases == null) {
1019                                 using_aliases = new ArrayList ();
1020                         } else {
1021                                 foreach (UsingAliasEntry entry in using_aliases) {
1022                                         if (uae.Alias == entry.Alias) {
1023                                                 Report.SymbolRelatedToPreviousError (uae.Location, uae.Alias);
1024                                                 Report.Error (1537, entry.Location, "The using alias `{0}' appeared previously in this namespace",
1025                                                         entry.Alias);
1026                                                 return;
1027                                         }
1028                                 }
1029                         }
1030
1031                         using_aliases.Add (uae);
1032                 }
1033
1034                 ///
1035                 /// Does extension methods look up to find a method which matches name and extensionType.
1036                 /// Search starts from this namespace and continues hierarchically up to top level.
1037                 ///
1038                 public ExtensionMethodGroupExpr LookupExtensionMethod (Type extensionType, string name, Location loc)
1039                 {
1040                         ArrayList candidates = null;
1041                         foreach (Namespace n in GetUsingTable ()) {
1042                                 ArrayList a = n.LookupExtensionMethod (extensionType, null, name);
1043                                 if (a == null)
1044                                         continue;
1045
1046                                 if (candidates == null)
1047                                         candidates = a;
1048                                 else
1049                                         candidates.AddRange (a);
1050                         }
1051
1052                         if (candidates != null)
1053                                 return new ExtensionMethodGroupExpr (candidates, parent, extensionType, loc);
1054
1055                         if (parent == null)
1056                                 return null;
1057
1058                         //
1059                         // Inspect parent namespaces in namespace expression
1060                         //
1061                         Namespace parent_ns = ns.Parent;
1062                         do {
1063                                 candidates = parent_ns.LookupExtensionMethod (extensionType, null, name);
1064                                 if (candidates != null)
1065                                         return new ExtensionMethodGroupExpr (candidates, parent, extensionType, loc);
1066
1067                                 parent_ns = parent_ns.Parent;
1068                         } while (parent_ns != null);
1069
1070                         //
1071                         // Continue in parent scope
1072                         //
1073                         return parent.LookupExtensionMethod (extensionType, name, loc);
1074                 }
1075
1076                 public FullNamedExpression LookupNamespaceOrType (string name, Location loc, bool ignore_cs0104)
1077                 {
1078                         // Precondition: Only simple names (no dots) will be looked up with this function.
1079                         FullNamedExpression resolved = null;
1080                         for (NamespaceEntry curr_ns = this; curr_ns != null; curr_ns = curr_ns.ImplicitParent) {
1081                                 if ((resolved = curr_ns.Lookup (name, loc, ignore_cs0104)) != null)
1082                                         break;
1083                         }
1084                         return resolved;
1085                 }
1086
1087                 public Type LookupTypeParameter (string name)
1088                 {
1089                         return null;
1090                 }
1091
1092                 public ICollection CompletionGetTypesStartingWith (DeclSpace ds, string prefix)
1093                 {
1094                         Hashtable result = new Hashtable ();
1095
1096                         for (NamespaceEntry curr_ns = this; curr_ns != null; curr_ns = curr_ns.ImplicitParent){
1097                                 foreach (Namespace using_ns in GetUsingTable ()){
1098                                         if (prefix.StartsWith (using_ns.Name)){
1099                                                 int ld = prefix.LastIndexOf ('.');
1100                                                 if (ld != -1){
1101                                                         string rest = prefix.Substring (ld+1);
1102
1103                                                         using_ns.CompletionGetTypesStartingWith (ds, rest, result);
1104                                                 }
1105                                         }
1106                                         using_ns.CompletionGetTypesStartingWith (ds, prefix, result);
1107                                 }
1108                         }
1109
1110                         return result.Keys;
1111                 }
1112
1113                 static void Error_AmbiguousTypeReference (Location loc, string name, FullNamedExpression t1, FullNamedExpression t2)
1114                 {
1115                         Report.SymbolRelatedToPreviousError (t1.Type);
1116                         Report.SymbolRelatedToPreviousError (t2.Type);
1117                         Report.Error (104, loc, "`{0}' is an ambiguous reference between `{1}' and `{2}'",
1118                                 name, t1.GetSignatureForError (), t2.GetSignatureForError ());
1119                 }
1120
1121                 // Looks-up a alias named @name in this and surrounding namespace declarations
1122                 public FullNamedExpression LookupAlias (string name)
1123                 {
1124                         for (NamespaceEntry n = this; n != null; n = n.ImplicitParent) {
1125                                 if (n.using_aliases == null)
1126                                         continue;
1127
1128                                 foreach (UsingAliasEntry ue in n.using_aliases) {
1129                                         if (ue.Alias == name)
1130                                                 return ue.Resolve (Doppelganger);
1131                                 }
1132                         }
1133
1134                         return null;
1135                 }
1136
1137                 private FullNamedExpression Lookup (string name, Location loc, bool ignore_cs0104)
1138                 {
1139                         //
1140                         // Check whether it's in the namespace.
1141                         //
1142                         FullNamedExpression fne = ns.Lookup (name, loc);
1143
1144                         //
1145                         // Check aliases.
1146                         //
1147                         if (using_aliases != null) {
1148                                 foreach (UsingAliasEntry ue in using_aliases) {
1149                                         if (ue.Alias == name) {
1150                                                 if (fne != null) {
1151                                                         if (Doppelganger != null) {
1152                                                                 // TODO: Namespace has broken location
1153                                                                 //Report.SymbolRelatedToPreviousError (fne.Location, null);
1154                                                                 Report.SymbolRelatedToPreviousError (ue.Location, null);
1155                                                                 Report.Error (576, loc,
1156                                                                         "Namespace `{0}' contains a definition with same name as alias `{1}'",
1157                                                                         GetSignatureForError (), name);
1158                                                         } else {
1159                                                                 return fne;
1160                                                         }
1161                                                 }
1162
1163                                                 return ue.Resolve (Doppelganger);
1164                                         }
1165                                 }
1166                         }
1167
1168                         if (fne != null)
1169                                 return fne;
1170
1171                         if (IsImplicit)
1172                                 return null;
1173
1174                         //
1175                         // Check using entries.
1176                         //
1177                         FullNamedExpression match = null;
1178                         foreach (Namespace using_ns in GetUsingTable ()) {
1179                                 match = using_ns.Lookup (name, loc);
1180                                 if (match == null || !(match is TypeExpr))
1181                                         continue;
1182                                 if (fne != null) {
1183                                         if (!ignore_cs0104)
1184                                                 Error_AmbiguousTypeReference (loc, name, fne, match);
1185                                         return null;
1186                                 }
1187                                 fne = match;
1188                         }
1189
1190                         return fne;
1191                 }
1192
1193                 Namespace [] GetUsingTable ()
1194                 {
1195                         if (namespace_using_table != null)
1196                                 return namespace_using_table;
1197
1198                         if (using_clauses == null) {
1199                                 namespace_using_table = empty_namespaces;
1200                                 return namespace_using_table;
1201                         }
1202
1203                         ArrayList list = new ArrayList (using_clauses.Count);
1204
1205                         foreach (UsingEntry ue in using_clauses) {
1206                                 Namespace using_ns = ue.Resolve (Doppelganger);
1207                                 if (using_ns == null)
1208                                         continue;
1209
1210                                 list.Add (using_ns);
1211                         }
1212
1213                         namespace_using_table = (Namespace[])list.ToArray (typeof (Namespace));
1214                         return namespace_using_table;
1215                 }
1216
1217                 static readonly string [] empty_using_list = new string [0];
1218
1219                 public int SymbolFileID {
1220                         get {
1221                                 if (symfile_id == 0 && file.SourceFileEntry != null) {
1222                                         int parent_id = parent == null ? 0 : parent.SymbolFileID;
1223
1224                                         string [] using_list = empty_using_list;
1225                                         if (using_clauses != null) {
1226                                                 using_list = new string [using_clauses.Count];
1227                                                 for (int i = 0; i < using_clauses.Count; i++)
1228                                                         using_list [i] = ((UsingEntry) using_clauses [i]).MemberName.GetName ();
1229                                         }
1230
1231                                         symfile_id = SymbolWriter.DefineNamespace (ns.Name, file.CompileUnitEntry, using_list, parent_id);
1232                                 }
1233                                 return symfile_id;
1234                         }
1235                 }
1236
1237                 static void MsgtryRef (string s)
1238                 {
1239                         Console.WriteLine ("    Try using -r:" + s);
1240                 }
1241
1242                 static void MsgtryPkg (string s)
1243                 {
1244                         Console.WriteLine ("    Try using -pkg:" + s);
1245                 }
1246
1247                 public static void Error_GlobalNamespaceRedefined (Location loc)
1248                 {
1249                         Report.Error (1681, loc, "You cannot redefine the global extern alias");
1250                 }
1251
1252                 public static void Error_NamespaceNotFound (Location loc, string name)
1253                 {
1254                         Report.Error (246, loc, "The type or namespace name `{0}' could not be found. Are you missing a using directive or an assembly reference?",
1255                                 name);
1256
1257                         switch (name) {
1258                         case "Gtk": case "GtkSharp":
1259                                 MsgtryPkg ("gtk-sharp");
1260                                 break;
1261
1262                         case "Gdk": case "GdkSharp":
1263                                 MsgtryPkg ("gdk-sharp");
1264                                 break;
1265
1266                         case "Glade": case "GladeSharp":
1267                                 MsgtryPkg ("glade-sharp");
1268                                 break;
1269
1270                         case "System.Drawing":
1271                         case "System.Web.Services":
1272                         case "System.Web":
1273                         case "System.Data":
1274                         case "System.Windows.Forms":
1275                                 MsgtryRef (name);
1276                                 break;
1277                         }
1278                 }
1279
1280                 /// <summary>
1281                 ///   Used to validate that all the using clauses are correct
1282                 ///   after we are finished parsing all the files.
1283                 /// </summary>
1284                 void VerifyUsing ()
1285                 {
1286                         if (using_aliases != null) {
1287                                 foreach (UsingAliasEntry ue in using_aliases)
1288                                         ue.Resolve (Doppelganger);
1289                         }
1290
1291                         if (using_clauses != null) {
1292                                 foreach (UsingEntry ue in using_clauses)
1293                                         ue.Resolve (Doppelganger);
1294                         }
1295                 }
1296
1297                 /// <summary>
1298                 ///   Used to validate that all the using clauses are correct
1299                 ///   after we are finished parsing all the files.
1300                 /// </summary>
1301                 static public void VerifyAllUsing ()
1302                 {
1303                         foreach (NamespaceEntry entry in entries)
1304                                 entry.VerifyUsing ();
1305                 }
1306
1307                 public string GetSignatureForError ()
1308                 {
1309                         return ns.GetSignatureForError ();
1310                 }
1311
1312                 public override string ToString ()
1313                 {
1314                         return ns.ToString ();
1315                 }
1316
1317                 #region IResolveContext Members
1318
1319                 public DeclSpace DeclContainer {
1320                         get { return SlaveDeclSpace; }
1321                 }
1322
1323                 public bool IsInObsoleteScope {
1324                         get { return SlaveDeclSpace.IsInObsoleteScope; }
1325                 }
1326
1327                 public bool IsInUnsafeScope {
1328                         get { return SlaveDeclSpace.IsInUnsafeScope; }
1329                 }
1330
1331                 public DeclSpace GenericDeclContainer {
1332                         get { return SlaveDeclSpace; }
1333                 }
1334
1335                 #endregion
1336         }
1337 }