mcs/mcs/namespace.cs

   1 //
   2 // namespace.cs: Tracks namespaces
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //   Marek Safar (marek.safar@seznam.cz)
   7 //
   8 // (C) 2001 Ximian, Inc.
   9 //
  10 using System;
  11 using System.Collections;
  12 using System.Collections.Specialized;
  13 using System.Reflection;
  14
  15 namespace Mono.CSharp {
  16
  17         public class RootNamespace : Namespace {
  18                 static MethodInfo get_namespaces_method;
  19
  20                 string alias_name;
  21                 Assembly referenced_assembly;
  22
  23                 Hashtable all_namespaces;
  24
  25                 static Hashtable root_namespaces;
  26                 public static GlobalRootNamespace Global;
  27
  28                 static RootNamespace ()
  29                 {
  30                         get_namespaces_method = typeof (Assembly).GetMethod ("GetNamespaces", BindingFlags.Instance | BindingFlags.NonPublic);
  31
  32                         Reset ();
  33                 }
  34
  35                 public static void Reset ()
  36                 {
  37                         root_namespaces = new Hashtable ();
  38                         Global = new GlobalRootNamespace ();
  39                         root_namespaces ["global"] = Global;
  40                 }
  41
  42                 protected RootNamespace (string alias_name, Assembly assembly)
  43                         : base (null, String.Empty)
  44                 {
  45                         this.alias_name = alias_name;
  46                         referenced_assembly = assembly;
  47
  48                         all_namespaces = new Hashtable ();
  49                         all_namespaces.Add ("", this);
  50
  51                         if (referenced_assembly != null)
  52                                 ComputeNamespaces (this.referenced_assembly);
  53                 }
  54
  55                 public static void DefineRootNamespace (string name, Assembly assembly)
  56                 {
  57                         if (name == "global") {
  58                                 NamespaceEntry.Error_GlobalNamespaceRedefined (Location.Null);
  59                                 return;
  60                         }
  61                         RootNamespace retval = GetRootNamespace (name);
  62                         if (retval == null || retval.referenced_assembly != assembly)
  63                                 root_namespaces [name] = new RootNamespace (name, assembly);
  64                 }
  65
  66                 public static RootNamespace GetRootNamespace (string name)
  67                 {
  68                         return (RootNamespace) root_namespaces [name];
  69                 }
  70
  71                 public virtual Type LookupTypeReflection (string name, Location loc)
  72                 {
  73                         return GetTypeInAssembly (referenced_assembly, name);
  74                 }
  75
  76                 public void RegisterNamespace (Namespace child)
  77                 {
  78                         if (child != this)
  79                                 all_namespaces.Add (child.Name, child);
  80                 }
  81
  82                 public bool IsNamespace (string name)
  83                 {
  84                         return all_namespaces.Contains (name);
  85                 }
  86
  87                 protected void RegisterNamespace (string dotted_name)
  88                 {
  89                         if (dotted_name != null && dotted_name.Length != 0 && ! IsNamespace (dotted_name))
  90                                 GetNamespace (dotted_name, true);
  91                 }
  92
  93                 void RegisterExtensionMethodClass (Type t)
  94                 {
  95                         string n = t.Namespace;
  96                         Namespace ns = n == null ? Global : (Namespace)all_namespaces [n];
  97                         if (ns == null)
  98                                 ns = GetNamespace (n, true);
  99
 100                         ns.RegisterExternalExtensionMethodClass (t);
 101                 }
 102
 103                 protected void ComputeNamespaces (Assembly assembly)
 104                 {
 105                         // How to test whether attribute exists without loading the assembly :-(
 106                         const string SystemCore = "System.Core, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089";
 107                         if (TypeManager.extension_attribute_type == null &&
 108                                 assembly.FullName == SystemCore) {
 109                                 TypeManager.extension_attribute_type = assembly.GetType("System.Runtime.CompilerServices.ExtensionAttribute");
 110                         }
 111
 112                         bool contains_extension_methods = TypeManager.extension_attribute_type != null &&
 113                                         assembly.IsDefined(TypeManager.extension_attribute_type, false);
 114
 115                         if (get_namespaces_method != null && !contains_extension_methods) {
 116                                 string [] namespaces = (string []) get_namespaces_method.Invoke (assembly, null);
 117                                 foreach (string ns in namespaces)
 118                                         RegisterNamespace (ns);
 119                                 return;
 120                         }
 121
 122                         foreach (Type t in assembly.GetExportedTypes ()) {
 123                                 if ((t.Attributes & Class.StaticClassAttribute) == Class.StaticClassAttribute &&
 124                                         contains_extension_methods && t.IsDefined (TypeManager.extension_attribute_type, false))
 125                                         RegisterExtensionMethodClass (t);
 126                                 else
 127                                         RegisterNamespace (t.Namespace);
 128                         }
 129                 }
 130
 131                 protected static Type GetTypeInAssembly (Assembly assembly, string name)
 132                 {
 133                         Type t = assembly.GetType (name);
 134                         if (t == null)
 135                                 return null;
 136
 137                         if (t.IsPointer)
 138                                 throw new InternalErrorException ("Use GetPointerType() to get a pointer");
 139
 140                         TypeAttributes ta = t.Attributes & TypeAttributes.VisibilityMask;
 141                         if (ta == TypeAttributes.NestedPrivate)
 142                                 return null;
 143
 144                         if ((ta == TypeAttributes.NotPublic ||
 145                              ta == TypeAttributes.NestedAssembly ||
 146                              ta == TypeAttributes.NestedFamANDAssem) &&
 147                             !TypeManager.IsFriendAssembly (t.Assembly))
 148                                 return null;
 149
 150                         return t;
 151                 }
 152
 153                 public override string ToString ()
 154                 {
 155                         return String.Format ("RootNamespace ({0}::)", alias_name);
 156                 }
 157
 158                 public override string GetSignatureForError ()
 159                 {
 160                         return alias_name + "::";
 161                 }
 162         }
 163
 164         public class GlobalRootNamespace : RootNamespace {
 165                 Assembly [] assemblies;
 166                 Module [] modules;
 167
 168                 public GlobalRootNamespace ()
 169                         : base ("global", null)
 170                 {
 171                         assemblies = new Assembly [0];
 172                 }
 173
 174                 public Assembly [] Assemblies {
 175                         get { return assemblies; }
 176                 }
 177
 178                 public Module [] Modules {
 179                         get { return modules; }
 180                 }
 181
 182                 public void AddAssemblyReference (Assembly a)
 183                 {
 184                         foreach (Assembly assembly in assemblies) {
 185                                 if (a == assembly)
 186                                         return;
 187                         }
 188
 189                         int top = assemblies.Length;
 190                         Assembly [] n = new Assembly [top + 1];
 191                         assemblies.CopyTo (n, 0);
 192                         n [top] = a;
 193                         assemblies = n;
 194
 195                         ComputeNamespaces (a);
 196                 }
 197
 198                 public void AddModuleReference (Module m)
 199                 {
 200                         int top = modules != null ? modules.Length : 0;
 201                         Module [] n = new Module [top + 1];
 202                         if (modules != null)
 203                                 modules.CopyTo (n, 0);
 204                         n [top] = m;
 205                         modules = n;
 206
 207                         if (m == CodeGen.Module.Builder)
 208                                 return;
 209
 210                         foreach (Type t in m.GetTypes ())
 211                                 RegisterNamespace (t.Namespace);
 212                 }
 213
 214                 public override void Error_NamespaceDoesNotExist(DeclSpace ds, Location loc, string name)
 215                 {
 216                         Report.Error (400, loc, "The type or namespace name `{0}' could not be found in the global namespace (are you missing an assembly reference?)",
 217                                 name);
 218                 }
 219
 220                 public override Type LookupTypeReflection (string name, Location loc)
 221                 {
 222                         Type found_type = null;
 223
 224                         foreach (Assembly a in assemblies) {
 225                                 Type t = GetTypeInAssembly (a, name);
 226                                 if (t == null)
 227                                         continue;
 228
 229                                 if (found_type == null) {
 230                                         found_type = t;
 231                                         continue;
 232                                 }
 233
 234                                 Report.SymbolRelatedToPreviousError (found_type);
 235                                 Report.SymbolRelatedToPreviousError (t);
 236                                 Report.Error (433, loc, "The imported type `{0}' is defined multiple times", name);
 237
 238                                 return found_type;
 239                         }
 240
 241                         if (modules != null) {
 242                                 foreach (Module module in modules) {
 243                                         Type t = module.GetType (name);
 244                                         if (t == null)
 245                                                 continue;
 246
 247                                         if (found_type == null) {
 248                                                 found_type = t;
 249                                                 continue;
 250                                         }
 251
 252                                         Report.SymbolRelatedToPreviousError (found_type);
 253                                         if (loc.IsNull) {
 254                                                 DeclSpace ds = TypeManager.LookupDeclSpace (t);
 255                                                 Report.Warning (1685, 1, ds.Location, "The type `{0}' conflicts with the predefined type `{1}' and will be ignored",
 256                                                         ds.GetSignatureForError (), TypeManager.CSharpName (found_type));
 257                                                 return found_type;
 258                                         }
 259                                         Report.SymbolRelatedToPreviousError (t);
 260                                         Report.Warning (436, 2, loc, "The type `{0}' conflicts with the imported type `{1}'. Ignoring the imported type definition",
 261                                                 TypeManager.CSharpName (t), TypeManager.CSharpName (found_type));
 262                                         return t;
 263                                 }
 264                         }
 265
 266                         return found_type;
 267                 }
 268         }
 269
 270         /// <summary>
 271         ///   Keeps track of the namespaces defined in the C# code.
 272         ///
 273         ///   This is an Expression to allow it to be referenced in the
 274         ///   compiler parse/intermediate tree during name resolution.
 275         /// </summary>
 276         public class Namespace : FullNamedExpression {
 277
 278                 Namespace parent;
 279                 string fullname;
 280                 IDictionary namespaces;
 281                 IDictionary declspaces;
 282                 Hashtable cached_types;
 283                 RootNamespace root;
 284                 ArrayList external_exmethod_classes;
 285
 286                 public readonly MemberName MemberName;
 287
 288                 /// <summary>
 289                 ///   Constructor Takes the current namespace and the
 290                 ///   name.  This is bootstrapped with parent == null
 291                 ///   and name = ""
 292                 /// </summary>
 293                 public Namespace (Namespace parent, string name)
 294                 {
 295                         // Expression members.
 296                         this.eclass = ExprClass.Namespace;
 297                         this.Type = typeof (Namespace);
 298                         this.loc = Location.Null;
 299
 300                         this.parent = parent;
 301
 302                         if (parent != null)
 303                                 this.root = parent.root;
 304                         else
 305                                 this.root = this as RootNamespace;
 306
 307                         if (this.root == null)
 308                                 throw new InternalErrorException ("Root namespaces must be created using RootNamespace");
 309
 310                         string pname = parent != null ? parent.Name : "";
 311
 312                         if (pname == "")
 313                                 fullname = name;
 314                         else
 315                                 fullname = parent.Name + "." + name;
 316
 317                         if (fullname == null)
 318                                 throw new InternalErrorException ("Namespace has a null fullname");
 319
 320                         if (parent != null && parent.MemberName != MemberName.Null)
 321                                 MemberName = new MemberName (parent.MemberName, name);
 322                         else if (name.Length == 0)
 323                                 MemberName = MemberName.Null;
 324                         else
 325                                 MemberName = new MemberName (name);
 326
 327                         namespaces = new HybridDictionary ();
 328                         cached_types = new Hashtable ();
 329
 330                         root.RegisterNamespace (this);
 331                 }
 332
 333                 public override Expression DoResolve (EmitContext ec)
 334                 {
 335                         return this;
 336                 }
 337
 338                 public virtual void Error_NamespaceDoesNotExist (DeclSpace ds, Location loc, string name)
 339                 {
 340                         if (name.IndexOf ('`') > 0) {
 341                                 FullNamedExpression retval = Lookup (ds, SimpleName.RemoveGenericArity (name), loc);
 342                                 if (retval != null) {
 343                                         Error_TypeArgumentsCannotBeUsed (retval.Type, loc, "type");
 344                                         return;
 345                                 }
 346                         } else {
 347                                 Type t = LookForAnyGenericType (name);
 348                                 if (t != null) {
 349                                         Error_InvalidNumberOfTypeArguments (t, loc);
 350                                         return;
 351                                 }
 352                         }
 353
 354                         Report.Error (234, loc, "The type or namespace name `{0}' does not exist in the namespace `{1}'. Are you missing an assembly reference?",
 355                                 name, FullName);
 356                 }
 357
 358                 public static void Error_InvalidNumberOfTypeArguments (Type t, Location loc)
 359                 {
 360                         Report.SymbolRelatedToPreviousError (t);
 361                         Report.Error (305, loc, "Using the generic type `{0}' requires `{1}' type argument(s)",
 362                                 TypeManager.CSharpName(t), TypeManager.GetNumberOfTypeArguments(t).ToString());
 363                 }
 364
 365                 public static void Error_TypeArgumentsCannotBeUsed(Type t, Location loc, string symbol)
 366                 {
 367                         Report.SymbolRelatedToPreviousError(t);
 368                         Report.Error(308, loc, "The non-generic {0} `{1}' cannot be used with the type argument(s)",
 369                                 symbol, TypeManager.CSharpName(t));
 370                 }
 371
 372                 public override void Emit (EmitContext ec)
 373                 {
 374                         throw new InternalErrorException ("Expression tree referenced namespace " + fullname + " during Emit ()");
 375                 }
 376
 377                 public override string GetSignatureForError ()
 378                 {
 379                         return Name;
 380                 }
 381
 382                 public Namespace GetNamespace (string name, bool create)
 383                 {
 384                         int pos = name.IndexOf ('.');
 385
 386                         Namespace ns;
 387                         string first;
 388                         if (pos >= 0)
 389                                 first = name.Substring (0, pos);
 390                         else
 391                                 first = name;
 392
 393                         ns = (Namespace) namespaces [first];
 394                         if (ns == null) {
 395                                 if (!create)
 396                                         return null;
 397
 398                                 ns = new Namespace (this, first);
 399                                 namespaces.Add (first, ns);
 400                         }
 401
 402                         if (pos >= 0)
 403                                 ns = ns.GetNamespace (name.Substring (pos + 1), create);
 404
 405                         return ns;
 406                 }
 407
 408                 TypeExpr LookupType (string name, Location loc)
 409                 {
 410                         if (cached_types.Contains (name))
 411                                 return cached_types [name] as TypeExpr;
 412
 413                         Type t = null;
 414                         if (declspaces != null) {
 415                                 DeclSpace tdecl = declspaces [name] as DeclSpace;
 416                                 if (tdecl != null) {
 417                                         //
 418                                         // Note that this is not:
 419                                         //
 420                                         //   t = tdecl.DefineType ()
 421                                         //
 422                                         // This is to make it somewhat more useful when a DefineType
 423                                         // fails due to problems in nested types (more useful in the sense
 424                                         // of fewer misleading error messages)
 425                                         //
 426                                         tdecl.DefineType ();
 427                                         t = tdecl.TypeBuilder;
 428                                 }
 429                         }
 430                         string lookup = t != null ? t.FullName : (fullname.Length == 0 ? name : fullname + "." + name);
 431                         Type rt = root.LookupTypeReflection (lookup, loc);
 432
 433                         // HACK: loc.IsNull when the type is core type
 434                         if (t == null || (rt != null && loc.IsNull))
 435                                 t = rt;
 436
 437                         TypeExpr te = t == null ? null : new TypeExpression (t, Location.Null);
 438                         cached_types [name] = te;
 439                         return te;
 440                 }
 441
 442                 ///
 443                 /// Used for better error reporting only
 444                 ///
 445                 public Type LookForAnyGenericType (string typeName)
 446                 {
 447                         if (declspaces == null)
 448                                 return null;
 449
 450                         typeName = SimpleName.RemoveGenericArity (typeName);
 451
 452                         foreach (DictionaryEntry de in declspaces) {
 453                                 string type_item = (string) de.Key;
 454                                 int pos = type_item.LastIndexOf ('`');
 455                                 if (pos == typeName.Length && String.Compare (typeName, 0, type_item, 0, pos) == 0)
 456                                         return ((DeclSpace) de.Value).TypeBuilder;
 457                         }
 458                         return null;
 459                 }
 460
 461                 public FullNamedExpression Lookup (DeclSpace ds, string name, Location loc)
 462                 {
 463                         if (namespaces.Contains (name))
 464                                 return (Namespace) namespaces [name];
 465
 466                         TypeExpr te = LookupType (name, loc);
 467                         if (te == null || !ds.CheckAccessLevel (te.Type))
 468                                 return null;
 469
 470                         return te;
 471                 }
 472
 473                 public void RegisterExternalExtensionMethodClass (Type type)
 474                 {
 475                         if (external_exmethod_classes == null)
 476                                 external_exmethod_classes = new ArrayList ();
 477
 478                         external_exmethod_classes.Add (type);
 479                 }
 480
 481                 ///
 482                 /// Looks for extension method in this namespace
 483                 ///
 484                 public ArrayList LookupExtensionMethod (Type extensionType, ClassOrStruct currentClass, string name, NamespaceEntry ns)
 485                 {
 486                         ArrayList found = null;
 487
 488                         if (declspaces != null) {
 489                                 IEnumerator e = declspaces.Values.GetEnumerator ();
 490                                 e.Reset ();
 491                                 while (e.MoveNext ()) {
 492                                         Class c = e.Current as Class;
 493                                         if (c == null)
 494                                                 continue;
 495
 496                                         if (!c.IsStaticClass)
 497                                                 continue;
 498
 499                                         ArrayList res = c.MemberCache.FindExtensionMethods (extensionType, name, c != currentClass);
 500                                         if (res == null)
 501                                                 continue;
 502
 503                                         if (found == null)
 504                                                 found = res;
 505                                         else
 506                                                 found.AddRange (res);
 507                                 }
 508                         }
 509
 510                         if (external_exmethod_classes == null)
 511                                 return found;
 512
 513                         foreach (Type t in external_exmethod_classes) {
 514                                 MemberCache m = TypeHandle.GetMemberCache (t);
 515                                 ArrayList res = m.FindExtensionMethods (extensionType, name, true);
 516                                 if (res == null)
 517                                         continue;
 518
 519                                 if (found == null)
 520                                         found = res;
 521                                 else
 522                                         found.AddRange (res);
 523                         }
 524
 525                         return found;
 526                 }
 527
 528                 public void AddDeclSpace (string name, DeclSpace ds)
 529                 {
 530                         if (declspaces == null)
 531                                 declspaces = new HybridDictionary ();
 532                         declspaces.Add (name, ds);
 533                 }
 534
 535                 /// <summary>
 536                 ///   The qualified name of the current namespace
 537                 /// </summary>
 538                 public string Name {
 539                         get { return fullname; }
 540                 }
 541
 542                 public override string FullName {
 543                         get { return fullname; }
 544                 }
 545
 546                 /// <summary>
 547                 ///   The parent of this namespace, used by the parser to "Pop"
 548                 ///   the current namespace declaration
 549                 /// </summary>
 550                 public Namespace Parent {
 551                         get { return parent; }
 552                 }
 553
 554                 public override string ToString ()
 555                 {
 556                         return String.Format ("Namespace ({0})", Name);
 557                 }
 558         }
 559
 560         public class NamespaceEntry {
 561                 Namespace ns;
 562                 NamespaceEntry parent, implicit_parent;
 563                 SourceFile file;
 564                 int symfile_id;
 565                 Hashtable aliases;
 566                 ArrayList using_clauses;
 567                 public bool DeclarationFound = false;
 568                 bool UsingFound;
 569
 570                 public readonly DeclSpace SlaveDeclSpace;
 571
 572                 ListDictionary extern_aliases;
 573
 574                 static ArrayList entries = new ArrayList ();
 575
 576                 public static void Reset ()
 577                 {
 578                         entries = new ArrayList ();
 579                 }
 580
 581                 //
 582                 // This class holds the location where a using definition is
 583                 // done, and whether it has been used by the program or not.
 584                 //
 585                 // We use this to flag using clauses for namespaces that do not
 586                 // exist.
 587                 //
 588                 public class UsingEntry : IResolveContext {
 589                         public readonly MemberName Name;
 590                         readonly NamespaceEntry NamespaceEntry;
 591                         readonly Location Location;
 592
 593                         public UsingEntry (NamespaceEntry entry, MemberName name, Location loc)
 594                         {
 595                                 Name = name;
 596                                 NamespaceEntry = entry;
 597                                 Location = loc;
 598                         }
 599
 600                         internal Namespace resolved;
 601
 602                         public Namespace Resolve ()
 603                         {
 604                                 if (resolved != null)
 605                                         return resolved;
 606
 607                                 FullNamedExpression fne = Name.GetTypeExpression ().ResolveAsTypeStep (this, false);
 608                                 if (fne == null) {
 609                                         Error_NamespaceNotFound (Location, Name.ToString ());
 610                                         return null;
 611                                 }
 612
 613                                 resolved = fne as Namespace;
 614                                 if (resolved == null) {
 615                                         Report.SymbolRelatedToPreviousError (fne.Type);
 616                                         Report.Error (138, Location,
 617                                                 "`{0}' is a type not a namespace. A using namespace directive can only be applied to namespaces", Name.ToString ());
 618                                 }
 619                                 return resolved;
 620                         }
 621
 622                         DeclSpace IResolveContext.DeclContainer {
 623                                 get { return NamespaceEntry.SlaveDeclSpace; }
 624                         }
 625
 626                         DeclSpace IResolveContext.GenericDeclContainer {
 627                                 get { return NamespaceEntry.SlaveDeclSpace; }
 628                         }
 629
 630                         bool IResolveContext.IsInObsoleteScope {
 631                                 get { return false; }
 632                         }
 633                         bool IResolveContext.IsInUnsafeScope {
 634                                 get { return false; }
 635                         }
 636                 }
 637
 638                 public abstract class AliasEntry {
 639                         public readonly string Name;
 640                         public readonly NamespaceEntry NamespaceEntry;
 641                         public readonly Location Location;
 642
 643                         protected AliasEntry (NamespaceEntry entry, string name, Location loc)
 644                         {
 645                                 Name = name;
 646                                 NamespaceEntry = entry;
 647                                 Location = loc;
 648                         }
 649
 650                         protected FullNamedExpression resolved;
 651                         bool error;
 652
 653                         public FullNamedExpression Resolve ()
 654                         {
 655                                 if (resolved != null || error)
 656                                         return resolved;
 657                                 resolved = DoResolve ();
 658                                 if (resolved == null)
 659                                         error = true;
 660                                 return resolved;
 661                         }
 662
 663                         protected abstract FullNamedExpression DoResolve ();
 664                 }
 665
 666                 public class LocalAliasEntry : AliasEntry, IResolveContext {
 667                         public readonly Expression Alias;
 668
 669                         public LocalAliasEntry (NamespaceEntry entry, string name, MemberName alias, Location loc) :
 670                                 base (entry, name, loc)
 671                         {
 672                                 Alias = alias.GetTypeExpression ();
 673                         }
 674
 675                         protected override FullNamedExpression DoResolve ()
 676                         {
 677                                 resolved = Alias.ResolveAsTypeStep (this, false);
 678                                 if (resolved == null)
 679                                         return null;
 680
 681                                 if (resolved.Type != null) {
 682                                         TypeAttributes attr = resolved.Type.Attributes & TypeAttributes.VisibilityMask;
 683                                         if (attr == TypeAttributes.NestedPrivate || attr == TypeAttributes.NestedFamily ||
 684                                                 ((attr == TypeAttributes.NestedFamORAssem || attr == TypeAttributes.NestedAssembly) &&
 685                                                 TypeManager.LookupDeclSpace (resolved.Type) == null)) {
 686                                                 Expression.ErrorIsInaccesible (Alias.Location, Alias.ToString ());
 687                                                 return null;
 688                                         }
 689                                 }
 690
 691                                 return resolved;
 692                         }
 693
 694                         DeclSpace IResolveContext.DeclContainer {
 695                                 get { return NamespaceEntry.SlaveDeclSpace; }
 696                         }
 697
 698                         DeclSpace IResolveContext.GenericDeclContainer {
 699                                 get { return NamespaceEntry.SlaveDeclSpace; }
 700                         }
 701
 702                         bool IResolveContext.IsInObsoleteScope {
 703                                 get { return false; }
 704                         }
 705                         bool IResolveContext.IsInUnsafeScope {
 706                                 get { return false; }
 707                         }
 708                 }
 709
 710                 public class ExternAliasEntry : AliasEntry {
 711                         public ExternAliasEntry (NamespaceEntry entry, string name, Location loc) :
 712                                 base (entry, name, loc)
 713                         {
 714                         }
 715
 716                         protected override FullNamedExpression DoResolve ()
 717                         {
 718                                 resolved = RootNamespace.GetRootNamespace (Name);
 719                                 if (resolved == null)
 720                                         Report.Error (430, Location, "The extern alias '" + Name +
 721                                                                         "' was not specified in a /reference option");
 722
 723                                 return resolved;
 724                         }
 725                 }
 726
 727                 public NamespaceEntry (NamespaceEntry parent, SourceFile file, string name)
 728                 {
 729                         this.parent = parent;
 730                         this.file = file;
 731                         entries.Add (this);
 732                         this.ID = entries.Count;
 733
 734                         if (parent != null)
 735                                 ns = parent.NS.GetNamespace (name, true);
 736                         else if (name != null)
 737                                 ns = RootNamespace.Global.GetNamespace (name, true);
 738                         else
 739                                 ns = RootNamespace.Global;
 740                         SlaveDeclSpace = new RootDeclSpace (this);
 741                 }
 742
 743                 private NamespaceEntry (NamespaceEntry parent, SourceFile file, Namespace ns, bool slave)
 744                 {
 745                         this.parent = parent;
 746                         this.file = file;
 747                         // no need to add self to 'entries', since we don't have any aliases or using entries.
 748                         this.ID = -1;
 749                         this.IsImplicit = true;
 750                         this.ns = ns;
 751                         this.SlaveDeclSpace = slave ? new RootDeclSpace (this) : null;
 752                 }
 753
 754                 //
 755                 // According to section 16.3.1 (using-alias-directive), the namespace-or-type-name is
 756                 // resolved as if the immediately containing namespace body has no using-directives.
 757                 //
 758                 // Section 16.3.2 says that the same rule is applied when resolving the namespace-name
 759                 // in the using-namespace-directive.
 760                 //
 761                 // To implement these rules, the expressions in the using directives are resolved using
 762                 // the "doppelganger" (ghostly bodiless duplicate).
 763                 //
 764                 NamespaceEntry doppelganger;
 765                 NamespaceEntry Doppelganger {
 766                         get {
 767                                 if (!IsImplicit && doppelganger == null)
 768                                         doppelganger = new NamespaceEntry (ImplicitParent, file, ns, true);
 769                                 return doppelganger;
 770                         }
 771                 }
 772
 773                 public readonly int ID;
 774                 public readonly bool IsImplicit;
 775
 776                 public Namespace NS {
 777                         get { return ns; }
 778                 }
 779
 780                 public NamespaceEntry Parent {
 781                         get { return parent; }
 782                 }
 783
 784                 public NamespaceEntry ImplicitParent {
 785                         get {
 786                                 if (parent == null)
 787                                         return null;
 788                                 if (implicit_parent == null) {
 789                                         implicit_parent = (parent.NS == ns.Parent)
 790                                                 ? parent
 791                                                 : new NamespaceEntry (parent, file, ns.Parent, false);
 792                                 }
 793                                 return implicit_parent;
 794                         }
 795                 }
 796
 797                 /// <summary>
 798                 ///   Records a new namespace for resolving name references
 799                 /// </summary>
 800                 public void Using (MemberName name, Location loc)
 801                 {
 802                         if (DeclarationFound){
 803                                 Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
 804                                 return;
 805                         }
 806
 807                         UsingFound = true;
 808
 809                         if (name.Equals (ns.MemberName))
 810                                 return;
 811
 812                         if (using_clauses == null)
 813                                 using_clauses = new ArrayList ();
 814
 815                         foreach (UsingEntry old_entry in using_clauses) {
 816                                 if (name.Equals (old_entry.Name)) {
 817                                         Report.Warning (105, 3, loc, "The using directive for `{0}' appeared previously in this namespace", name.GetName ());
 818                                         return;
 819                                 }
 820                         }
 821
 822                         UsingEntry ue = new UsingEntry (Doppelganger, name, loc);
 823                         using_clauses.Add (ue);
 824                 }
 825
 826                 public void UsingAlias (string name, MemberName alias, Location loc)
 827                 {
 828                         if (DeclarationFound){
 829                                 Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
 830                                 return;
 831                         }
 832
 833                         UsingFound = true;
 834
 835                         if (aliases == null)
 836                                 aliases = new Hashtable ();
 837
 838                         if (aliases.Contains (name)) {
 839                                 AliasEntry ae = (AliasEntry) aliases [name];
 840                                 Report.SymbolRelatedToPreviousError (ae.Location, ae.Name);
 841                                 Report.Error (1537, loc, "The using alias `{0}' appeared previously in this namespace", name);
 842                                 return;
 843                         }
 844
 845                         if (RootContext.Version == LanguageVersion.Default &&
 846                             name == "global" && RootContext.WarningLevel >= 2)
 847                                 Report.Warning (440, 2, loc, "An alias named `global' will not be used when resolving 'global::';" +
 848                                         " the global namespace will be used instead");
 849
 850                         // FIXME: get correct error number.  See if the above check can be merged
 851                         if (extern_aliases != null && extern_aliases.Contains (name)) {
 852                                 AliasEntry ae = (AliasEntry) extern_aliases [name];
 853                                 Report.SymbolRelatedToPreviousError (ae.Location, ae.Name);
 854                                 Report.Error (1537, loc, "The using alias `{0}' appeared previously in this namespace", name);
 855                                 return;
 856                         }
 857
 858                         aliases [name] = new LocalAliasEntry (Doppelganger, name, alias, loc);
 859                 }
 860
 861                 public void UsingExternalAlias (string name, Location loc)
 862                 {
 863                         if (UsingFound || DeclarationFound) {
 864                                 Report.Error (439, loc, "An extern alias declaration must precede all other elements");
 865                                 return;
 866                         }
 867
 868                         // Share the extern_aliases field with the Doppelganger
 869                         if (extern_aliases == null) {
 870                                 extern_aliases = new ListDictionary ();
 871                                 Doppelganger.extern_aliases = extern_aliases;
 872                         }
 873
 874                         if (extern_aliases.Contains (name)) {
 875                                 AliasEntry ae = (AliasEntry) extern_aliases [name];
 876                                 Report.SymbolRelatedToPreviousError (ae.Location, ae.Name);
 877                                 Report.Error (1537, loc, "The using alias `{0}' appeared previously in this namespace", name);
 878                                 return;
 879                         }
 880
 881                         if (name == "global") {
 882                                 Error_GlobalNamespaceRedefined (loc);
 883                                 return;
 884                         }
 885
 886                         // Register the alias in aliases and extern_aliases, since we need both of them
 887                         // to keep things simple (different resolution scenarios)
 888                         ExternAliasEntry alias = new ExternAliasEntry (Doppelganger, name, loc);
 889                         extern_aliases [name] = alias;
 890                 }
 891
 892                 ///
 893                 /// Does extension methods look up to find a method which matches name and extensionType.
 894                 /// Search starts from this namespace and continues hierarchically up to top level.
 895                 ///
 896                 public ExtensionMethodGroupExpr LookupExtensionMethod (Type extensionType, ClassOrStruct currentClass, string name)
 897                 {
 898                         ArrayList candidates = null;
 899                         if (currentClass != null) {
 900                                 candidates = ns.LookupExtensionMethod (extensionType, currentClass, name, this);
 901                                 if (candidates != null)
 902                                         return new ExtensionMethodGroupExpr (candidates, this, extensionType, Location.Null);
 903                         }
 904
 905                         foreach (Namespace n in GetUsingTable ()) {
 906                                 ArrayList a = n.LookupExtensionMethod (extensionType, null, name, this);
 907                                 if (a == null)
 908                                         continue;
 909
 910                                 if (candidates == null)
 911                                         candidates = a;
 912                                 else
 913                                         candidates.AddRange (a);
 914                         }
 915
 916                         if (candidates != null)
 917                                 return new ExtensionMethodGroupExpr (candidates, parent, extensionType, Location.Null);
 918
 919                         if (parent == null)
 920                                 return null;
 921
 922                         return parent.LookupExtensionMethod (extensionType, currentClass, name);
 923                 }
 924
 925                 public FullNamedExpression LookupNamespaceOrType (DeclSpace ds, string name, Location loc, bool ignore_cs0104)
 926                 {
 927                         // Precondition: Only simple names (no dots) will be looked up with this function.
 928                         FullNamedExpression resolved = null;
 929                         for (NamespaceEntry curr_ns = this; curr_ns != null; curr_ns = curr_ns.ImplicitParent) {
 930                                 if ((resolved = curr_ns.Lookup (ds, name, loc, ignore_cs0104)) != null)
 931                                         break;
 932                         }
 933                         return resolved;
 934                 }
 935
 936                 static void Error_AmbiguousTypeReference (Location loc, string name, FullNamedExpression t1, FullNamedExpression t2)
 937                 {
 938                         Report.Error (104, loc, "`{0}' is an ambiguous reference between `{1}' and `{2}'",
 939                                 name, t1.FullName, t2.FullName);
 940                 }
 941
 942                 // Looks-up a alias named @name in this and surrounding namespace declarations
 943                 public FullNamedExpression LookupAlias (string name)
 944                 {
 945                         AliasEntry entry = null;
 946                         for (NamespaceEntry n = this; n != null; n = n.ImplicitParent) {
 947                                 if (n.extern_aliases != null && (entry = n.extern_aliases [name] as AliasEntry) != null)
 948                                         break;
 949                                 if (n.aliases != null && (entry = n.aliases [name] as AliasEntry) != null)
 950                                         break;
 951                         }
 952                         return entry == null ? null : entry.Resolve ();
 953                 }
 954
 955                 private FullNamedExpression Lookup (DeclSpace ds, string name, Location loc, bool ignore_cs0104)
 956                 {
 957                         //
 958                         // Check whether it's in the namespace.
 959                         //
 960                         FullNamedExpression fne = ns.Lookup (ds, name, loc);
 961                         if (fne != null)
 962                                 return fne;
 963
 964                         if (extern_aliases != null) {
 965                                 AliasEntry entry = extern_aliases [name] as AliasEntry;
 966                                 if (entry != null)
 967                                         return entry.Resolve ();
 968                         }
 969
 970                         if (IsImplicit)
 971                                 return null;
 972
 973                         //
 974                         // Check aliases.
 975                         //
 976                         if (aliases != null) {
 977                                 AliasEntry entry = aliases [name] as AliasEntry;
 978                                 if (entry != null)
 979                                         return entry.Resolve ();
 980                         }
 981
 982                         //
 983                         // Check using entries.
 984                         //
 985                         FullNamedExpression match = null;
 986                         foreach (Namespace using_ns in GetUsingTable ()) {
 987                                 match = using_ns.Lookup (ds, name, loc);
 988                                 if (match == null || !(match is TypeExpr))
 989                                         continue;
 990                                 if (fne != null) {
 991                                         if (!ignore_cs0104)
 992                                                 Error_AmbiguousTypeReference (loc, name, fne, match);
 993                                         return null;
 994                                 }
 995                                 fne = match;
 996                         }
 997
 998                         return fne;
 999                 }
1000
1001                 // Our cached computation.
1002                 static readonly Namespace [] empty_namespaces = new Namespace [0];
1003                 Namespace [] namespace_using_table;
1004                 Namespace [] GetUsingTable ()
1005                 {
1006                         if (namespace_using_table != null)
1007                                 return namespace_using_table;
1008
1009                         if (using_clauses == null) {
1010                                 namespace_using_table = empty_namespaces;
1011                                 return namespace_using_table;
1012                         }
1013
1014                         ArrayList list = new ArrayList (using_clauses.Count);
1015
1016                         foreach (UsingEntry ue in using_clauses) {
1017                                 Namespace using_ns = ue.Resolve ();
1018                                 if (using_ns == null)
1019                                         continue;
1020
1021                                 list.Add (using_ns);
1022                         }
1023
1024                         namespace_using_table = new Namespace [list.Count];
1025                         list.CopyTo (namespace_using_table, 0);
1026                         return namespace_using_table;
1027                 }
1028
1029                 static readonly string [] empty_using_list = new string [0];
1030
1031                 public int SymbolFileID {
1032                         get {
1033                                 if (symfile_id == 0 && file.SourceFileEntry != null) {
1034                                         int parent_id = parent == null ? 0 : parent.SymbolFileID;
1035
1036                                         string [] using_list = empty_using_list;
1037                                         if (using_clauses != null) {
1038                                                 using_list = new string [using_clauses.Count];
1039                                                 for (int i = 0; i < using_clauses.Count; i++)
1040                                                         using_list [i] = ((UsingEntry) using_clauses [i]).Name.ToString ();
1041                                         }
1042
1043                                         symfile_id = CodeGen.SymbolWriter.DefineNamespace (ns.Name, file.SourceFileEntry, using_list, parent_id);
1044                                 }
1045                                 return symfile_id;
1046                         }
1047                 }
1048
1049                 static void MsgtryRef (string s)
1050                 {
1051                         Console.WriteLine ("    Try using -r:" + s);
1052                 }
1053
1054                 static void MsgtryPkg (string s)
1055                 {
1056                         Console.WriteLine ("    Try using -pkg:" + s);
1057                 }
1058
1059                 public static void Error_GlobalNamespaceRedefined (Location loc)
1060                 {
1061                         Report.Error (1681, loc, "You cannot redefine the global extern alias");
1062                 }
1063
1064                 public static void Error_NamespaceNotFound (Location loc, string name)
1065                 {
1066                         Report.Error (246, loc, "The type or namespace name `{0}' could not be found. Are you missing a using directive or an assembly reference?",
1067                                 name);
1068
1069                         switch (name) {
1070                         case "Gtk": case "GtkSharp":
1071                                 MsgtryPkg ("gtk-sharp");
1072                                 break;
1073
1074                         case "Gdk": case "GdkSharp":
1075                                 MsgtryPkg ("gdk-sharp");
1076                                 break;
1077
1078                         case "Glade": case "GladeSharp":
1079                                 MsgtryPkg ("glade-sharp");
1080                                 break;
1081
1082                         case "System.Drawing":
1083                         case "System.Web.Services":
1084                         case "System.Web":
1085                         case "System.Data":
1086                         case "System.Windows.Forms":
1087                                 MsgtryRef (name);
1088                                 break;
1089                         }
1090                 }
1091
1092                 /// <summary>
1093                 ///   Used to validate that all the using clauses are correct
1094                 ///   after we are finished parsing all the files.
1095                 /// </summary>
1096                 void VerifyUsing ()
1097                 {
1098                         if (extern_aliases != null) {
1099                                 foreach (DictionaryEntry de in extern_aliases)
1100                                         ((AliasEntry) de.Value).Resolve ();
1101                         }
1102
1103                         if (using_clauses != null) {
1104                                 foreach (UsingEntry ue in using_clauses)
1105                                         ue.Resolve ();
1106                         }
1107
1108                         if (aliases != null) {
1109                                 foreach (DictionaryEntry de in aliases)
1110                                         ((AliasEntry) de.Value).Resolve ();
1111                         }
1112                 }
1113
1114                 /// <summary>
1115                 ///   Used to validate that all the using clauses are correct
1116                 ///   after we are finished parsing all the files.
1117                 /// </summary>
1118                 static public void VerifyAllUsing ()
1119                 {
1120                         foreach (NamespaceEntry entry in entries)
1121                                 entry.VerifyUsing ();
1122                 }
1123
1124                 public string GetSignatureForError ()
1125                 {
1126                         return ns.GetSignatureForError ();
1127                 }
1128
1129                 public override string ToString ()
1130                 {
1131                         return ns.ToString ();
1132                 }
1133         }
1134 }