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.Generic;
  13 using System.Reflection;
  14 using System.Linq;
  15
  16 namespace Mono.CSharp {
  17
  18         public class RootNamespace : Namespace {
  19
  20                 protected readonly string alias_name;
  21                 protected Assembly [] referenced_assemblies;
  22
  23                 Dictionary<string, Namespace> all_namespaces;
  24
  25                 public RootNamespace (string alias_name)
  26                         : base (null, String.Empty)
  27                 {
  28                         this.alias_name = alias_name;
  29                         referenced_assemblies = new Assembly [0];
  30
  31                         all_namespaces = new Dictionary<string, Namespace> ();
  32                         all_namespaces.Add ("", this);
  33                 }
  34
  35                 public void AddAssemblyReference (Assembly a)
  36                 {
  37                         foreach (Assembly assembly in referenced_assemblies) {
  38                                 if (a == assembly)
  39                                         return;
  40                         }
  41
  42                         int top = referenced_assemblies.Length;
  43                         Assembly [] n = new Assembly [top + 1];
  44                         referenced_assemblies.CopyTo (n, 0);
  45                         n [top] = a;
  46                         referenced_assemblies = n;
  47                 }
  48
  49                 public void ImportTypes (CompilerContext ctx)
  50                 {
  51                         foreach (Assembly a in referenced_assemblies) {
  52                                 try {
  53                                         ImportAssembly (a);
  54                                 } catch (TypeLoadException e) {
  55                                         ctx.Report.Error (11, Location.Null, e.Message);
  56                                 } catch (System.IO.FileNotFoundException) {
  57                                         ctx.Report.Error (12, Location.Null, "An assembly `{0}' is used without being referenced",
  58                                                 a.FullName);
  59                                 }
  60                         }
  61                 }
  62
  63                 public void RegisterNamespace (Namespace child)
  64                 {
  65                         if (child != this)
  66                                 all_namespaces.Add (child.Name, child);
  67                 }
  68
  69                 public bool IsNamespace (string name)
  70                 {
  71                         return all_namespaces.ContainsKey (name);
  72                 }
  73
  74                 protected void RegisterNamespace (string dotted_name)
  75                 {
  76                         if (dotted_name != null && dotted_name.Length != 0 && ! IsNamespace (dotted_name))
  77                                 GetNamespace (dotted_name, true);
  78                 }
  79
  80                 public void ImportAssembly (Assembly assembly)
  81                 {
  82                         Type extension_type = null;
  83                         var all_attributes = CustomAttributeData.GetCustomAttributes (assembly);
  84                         foreach (var attr in all_attributes) {
  85                                 var dt = attr.Constructor.DeclaringType;
  86                                 if (dt.Name == "ExtensionAttribute" && dt.Namespace == "System.Runtime.CompilerServices") {
  87                                         extension_type = dt;
  88                                         break;
  89                                 }
  90                         }
  91
  92                         //
  93                         // This part tries to simulate loading of top-level
  94                         // types only, any missing dependencies are ignores here.
  95                         // Full error report is reported later when the type is
  96                         // actually used
  97                         //
  98                         Type[] all_types;
  99                         try {
 100                                 all_types = assembly.GetTypes ();
 101                         } catch (ReflectionTypeLoadException e) {
 102                                 all_types = e.Types;
 103                         }
 104
 105                         Namespace ns = this;
 106                         string prev_namespace = null;
 107                         foreach (var t in all_types) {
 108                                 if (t == null || t.IsNested)
 109                                         continue;
 110
 111                                 if (t.Name[0] == '<')
 112                                         continue;
 113
 114                                 var it = Import.CreateType (t);
 115                                 if (it == null)
 116                                         continue;
 117
 118                                 if (prev_namespace != t.Namespace) {
 119                                         ns = t.Namespace == null ? this : GetNamespace (t.Namespace, true);
 120                                         prev_namespace = t.Namespace;
 121                                 }
 122
 123                                 ns.AddType (it);
 124
 125                                 if (it.IsStatic && extension_type != null && t.IsDefined (extension_type, false)) {
 126                                         it.SetExtensionMethodContainer ();
 127                                 }
 128                         }
 129                 }
 130
 131                 public override string GetSignatureForError ()
 132                 {
 133                         return alias_name + "::";
 134                 }
 135         }
 136
 137         public class GlobalRootNamespace : RootNamespace {
 138                 Module [] modules;
 139                 Dictionary<string, RootNamespace> root_namespaces;
 140
 141                 public static GlobalRootNamespace Instance = new GlobalRootNamespace ();
 142
 143                 GlobalRootNamespace ()
 144                         : base ("global")
 145                 {
 146                         root_namespaces = new Dictionary<string, RootNamespace> ();
 147                         root_namespaces.Add (alias_name, this);
 148                 }
 149
 150                 public static void Reset ()
 151                 {
 152                         Instance = new GlobalRootNamespace ();
 153                 }
 154
 155                 public Assembly [] Assemblies {
 156                     get { return referenced_assemblies; }
 157                 }
 158
 159                 public Module [] Modules {
 160                         get { return modules; }
 161                 }
 162
 163                 public void AddModuleReference (Module m)
 164                 {
 165                         int top = modules != null ? modules.Length : 0;
 166                         Module [] n = new Module [top + 1];
 167                         if (modules != null)
 168                                 modules.CopyTo (n, 0);
 169                         n [top] = m;
 170                         modules = n;
 171
 172                         if (m == RootContext.ToplevelTypes.Builder)
 173                                 return;
 174
 175                         foreach (var t in m.GetTypes ())
 176                                 RegisterNamespace (t.Namespace);
 177                 }
 178
 179                 public void ComputeNamespaces (CompilerContext ctx)
 180                 {
 181                         foreach (RootNamespace rn in root_namespaces.Values) {
 182                                 rn.ImportTypes (ctx);
 183                         }
 184                 }
 185
 186                 public void DefineRootNamespace (string alias, Assembly assembly, CompilerContext ctx)
 187                 {
 188                         if (alias == alias_name) {
 189                                 NamespaceEntry.Error_GlobalNamespaceRedefined (Location.Null, ctx.Report);
 190                                 return;
 191                         }
 192
 193                         RootNamespace retval = GetRootNamespace (alias);
 194                         if (retval == null) {
 195                                 retval = new RootNamespace (alias);
 196                                 root_namespaces.Add (alias, retval);
 197                         }
 198
 199                         retval.AddAssemblyReference (assembly);
 200                 }
 201
 202                 public override void Error_NamespaceDoesNotExist (Location loc, string name, int arity, IMemberContext ctx)
 203                 {
 204                         ctx.Compiler.Report.Error (400, loc,
 205                                 "The type or namespace name `{0}' could not be found in the global namespace (are you missing an assembly reference?)",
 206                                 name);
 207                 }
 208
 209                 public RootNamespace GetRootNamespace (string name)
 210                 {
 211                         RootNamespace rn;
 212                         if (!root_namespaces.TryGetValue (name, out rn))
 213                                 return null;
 214
 215                         return rn;
 216                 }
 217         }
 218
 219         /// <summary>
 220         ///   Keeps track of the namespaces defined in the C# code.
 221         ///
 222         ///   This is an Expression to allow it to be referenced in the
 223         ///   compiler parse/intermediate tree during name resolution.
 224         /// </summary>
 225         public class Namespace : FullNamedExpression {
 226
 227                 Namespace parent;
 228                 string fullname;
 229                 protected Dictionary<string, Namespace> namespaces;
 230                 protected Dictionary<string, IList<TypeSpec>> types;
 231                 Dictionary<string, TypeExpr> cached_types;
 232                 RootNamespace root;
 233                 bool cls_checked;
 234
 235                 public readonly MemberName MemberName;
 236
 237                 /// <summary>
 238                 ///   Constructor Takes the current namespace and the
 239                 ///   name.  This is bootstrapped with parent == null
 240                 ///   and name = ""
 241                 /// </summary>
 242                 public Namespace (Namespace parent, string name)
 243                 {
 244                         // Expression members.
 245                         this.eclass = ExprClass.Namespace;
 246                         this.Type = InternalType.FakeInternalType;
 247                         this.loc = Location.Null;
 248
 249                         this.parent = parent;
 250
 251                         if (parent != null)
 252                                 this.root = parent.root;
 253                         else
 254                                 this.root = this as RootNamespace;
 255
 256                         if (this.root == null)
 257                                 throw new InternalErrorException ("Root namespaces must be created using RootNamespace");
 258
 259                         string pname = parent != null ? parent.fullname : "";
 260
 261                         if (pname == "")
 262                                 fullname = name;
 263                         else
 264                                 fullname = parent.fullname + "." + name;
 265
 266                         if (fullname == null)
 267                                 throw new InternalErrorException ("Namespace has a null fullname");
 268
 269                         if (parent != null && parent.MemberName != MemberName.Null)
 270                                 MemberName = new MemberName (parent.MemberName, name);
 271                         else if (name.Length == 0)
 272                                 MemberName = MemberName.Null;
 273                         else
 274                                 MemberName = new MemberName (name);
 275
 276                         namespaces = new Dictionary<string, Namespace> ();
 277                         cached_types = new Dictionary<string, TypeExpr> ();
 278
 279                         root.RegisterNamespace (this);
 280                 }
 281
 282                 #region Properties
 283
 284                 /// <summary>
 285                 ///   The qualified name of the current namespace
 286                 /// </summary>
 287                 public string Name {
 288                         get { return fullname; }
 289                 }
 290
 291                 /// <summary>
 292                 ///   The parent of this namespace, used by the parser to "Pop"
 293                 ///   the current namespace declaration
 294                 /// </summary>
 295                 public Namespace Parent {
 296                         get { return parent; }
 297                 }
 298
 299                 #endregion
 300
 301                 protected override Expression DoResolve (ResolveContext ec)
 302                 {
 303                         return this;
 304                 }
 305
 306                 public virtual void Error_NamespaceDoesNotExist (Location loc, string name, int arity, IMemberContext ctx)
 307                 {
 308                         FullNamedExpression retval = Lookup (ctx.Compiler, name, -System.Math.Max (1, arity), loc);
 309                         if (retval != null) {
 310                                 Error_TypeArgumentsCannotBeUsed (ctx.Compiler.Report, loc, retval.Type, arity);
 311                                 return;
 312                         }
 313
 314                         Namespace ns;
 315                         if (arity > 0 && namespaces.TryGetValue (name, out ns)) {
 316                                 ns.Error_TypeArgumentsCannotBeUsed (ctx.Compiler.Report, loc, null, arity);
 317                                 return;
 318                         }
 319
 320                         ctx.Compiler.Report.Error (234, loc,
 321                                 "The type or namespace name `{0}' does not exist in the namespace `{1}'. Are you missing an assembly reference?",
 322                                 name, GetSignatureForError ());
 323                 }
 324
 325                 public override string GetSignatureForError ()
 326                 {
 327                         return fullname;
 328                 }
 329
 330                 public Namespace GetNamespace (string name, bool create)
 331                 {
 332                         int pos = name.IndexOf ('.');
 333
 334                         Namespace ns;
 335                         string first;
 336                         if (pos >= 0)
 337                                 first = name.Substring (0, pos);
 338                         else
 339                                 first = name;
 340
 341                         if (!namespaces.TryGetValue (first, out ns)) {
 342                                 if (!create)
 343                                         return null;
 344
 345                                 ns = new Namespace (this, first);
 346                                 namespaces.Add (first, ns);
 347                         }
 348
 349                         if (pos >= 0)
 350                                 ns = ns.GetNamespace (name.Substring (pos + 1), create);
 351
 352                         return ns;
 353                 }
 354
 355                 public TypeExpr LookupType (CompilerContext ctx, string name, int arity, Location loc)
 356                 {
 357                         if (types == null)
 358                                 return null;
 359
 360                         TypeExpr te;
 361                         if (arity == 0 && cached_types.TryGetValue (name, out te))
 362                                 return te;
 363
 364                         IList<TypeSpec> found;
 365                         if (!types.TryGetValue (name, out found))
 366                                 return null;
 367
 368                         TypeSpec best = null;
 369                         foreach (var ts in found) {
 370                                 if (ts.Arity == arity) {
 371                                         if (best == null) {
 372                                                 best = ts;
 373                                                 continue;
 374                                         }
 375
 376                                         if (best.MemberDefinition.IsImported && ts.MemberDefinition.IsImported) {
 377                                                 ctx.Report.SymbolRelatedToPreviousError (best);
 378                                                 ctx.Report.SymbolRelatedToPreviousError (ts);
 379                                                 ctx.Report.Error (433, loc, "The imported type `{0}' is defined multiple times", ts.GetSignatureForError ());
 380                                                 break;
 381                                         }
 382
 383                                         var pts = best as PredefinedTypeSpec;
 384                                         if (pts == null)
 385                                                 pts = ts as PredefinedTypeSpec;
 386
 387                                         if (pts != null) {
 388                                                 ctx.Report.SymbolRelatedToPreviousError (best);
 389                                                 ctx.Report.SymbolRelatedToPreviousError (ts);
 390                                                 ctx.Report.Warning (1685, 1, loc,
 391                                                         "The predefined type `{0}.{1}' is redefined in the source code. Ignoring the local type definition",
 392                                                         pts.Namespace, pts.Name);
 393                                                 best = pts;
 394                                                 continue;
 395                                         }
 396
 397                                         if (best.MemberDefinition.IsImported)
 398                                                 best = ts;
 399
 400                                         if ((best.Modifiers & Modifiers.INTERNAL) != 0 && !TypeManager.IsThisOrFriendAssembly (CodeGen.Assembly.Builder, best.MemberDefinition.Assembly))
 401                                                 continue;
 402
 403                                         if (ts.MemberDefinition.IsImported)
 404                                                 ctx.Report.SymbolRelatedToPreviousError (ts);
 405
 406                                         ctx.Report.Warning (436, 2, loc,
 407                                                 "The type `{0}' conflicts with the imported type of same name'. Ignoring the imported type definition",
 408                                                 best.GetSignatureForError ());
 409                                 }
 410
 411                                 //
 412                                 // Lookup for the best candidate with closest arity match
 413                                 //
 414                                 if (arity < 0) {
 415                                         if (best == null) {
 416                                                 best = ts;
 417                                         } else if (System.Math.Abs (ts.Arity + arity) < System.Math.Abs (best.Arity + arity)) {
 418                                                 best = ts;
 419                                         }
 420                                 }
 421                         }
 422
 423                         if (best == null)
 424                                 return null;
 425
 426                         te = new TypeExpression (best, Location.Null);
 427
 428                         // TODO MemberCache: Cache more
 429                         if (arity == 0)
 430                                 cached_types.Add (name, te);
 431
 432                         return te;
 433                 }
 434
 435                 TypeSpec LookupType (string name, int arity)
 436                 {
 437                         if (types == null)
 438                                 return null;
 439
 440                         IList<TypeSpec> found;
 441                         if (types.TryGetValue (name, out found)) {
 442                                 TypeSpec best = null;
 443
 444                                 foreach (var ts in found) {
 445                                         if (ts.Arity == arity)
 446                                                 return ts;
 447
 448                                         //
 449                                         // Lookup for the best candidate with closest arity match
 450                                         //
 451                                         if (arity < 0) {
 452                                                 if (best == null) {
 453                                                         best = ts;
 454                                                 } else if (System.Math.Abs (ts.Arity + arity) < System.Math.Abs (best.Arity + arity)) {
 455                                                         best = ts;
 456                                                 }
 457                                         }
 458                                 }
 459
 460                                 return best;
 461                         }
 462
 463                         return null;
 464                 }
 465
 466                 public FullNamedExpression Lookup (CompilerContext ctx, string name, int arity, Location loc)
 467                 {
 468                         if (arity == 0 && namespaces.ContainsKey (name))
 469                                 return namespaces [name];
 470
 471                         return LookupType (ctx, name, arity, loc);
 472                 }
 473
 474                 //
 475                 // Completes types with the given `prefix'
 476                 //
 477                 public IEnumerable<string> CompletionGetTypesStartingWith (string prefix)
 478                 {
 479                         if (types == null)
 480                                 return Enumerable.Empty<string> ();
 481
 482                         var res = from item in types
 483                                           where item.Key.StartsWith (prefix) && item.Value.Any (l => (l.Modifiers & Modifiers.PUBLIC) != 0)
 484                                           select item.Key;
 485
 486                         if (namespaces != null)
 487                                 res = res.Concat (from item in namespaces where item.Key.StartsWith (prefix) select item.Key);
 488
 489                         return res;
 490                 }
 491
 492                 ///
 493                 /// Looks for extension method in this namespace
 494                 ///
 495                 public List<MethodSpec> LookupExtensionMethod (TypeSpec extensionType, ClassOrStruct currentClass, string name, int arity)
 496                 {
 497                         if (types == null)
 498                                 return null;
 499
 500                         List<MethodSpec> found = null;
 501
 502                         var invocation_type = currentClass == null ? InternalType.FakeInternalType : currentClass.CurrentType;
 503
 504                         // TODO: Add per namespace flag when at least 1 type has extension
 505
 506                         foreach (var tgroup in types.Values) {
 507                                 foreach (var ts in tgroup) {
 508                                         if ((ts.Modifiers & Modifiers.METHOD_EXTENSION) == 0)
 509                                                 continue;
 510
 511                                         var res = ts.MemberCache.FindExtensionMethods (invocation_type, extensionType, name, arity);
 512                                         if (res == null)
 513                                                 continue;
 514
 515                                         if (found == null) {
 516                                                 found = res;
 517                                         } else {
 518                                                 found.AddRange (res);
 519                                         }
 520                                 }
 521                         }
 522
 523                         return found;
 524                 }
 525
 526                 public void AddType (TypeSpec ts)
 527                 {
 528                         if (types == null) {
 529                                 types = new Dictionary<string, IList<TypeSpec>> (64);
 530                         }
 531
 532                         var name = ts.Name;
 533                         IList<TypeSpec> existing;
 534                         if (types.TryGetValue (name, out existing)) {
 535                                 TypeSpec better_type;
 536                                 TypeSpec found;
 537                                 if (existing.Count == 1) {
 538                                         found = existing[0];
 539                                         if (ts.Arity == found.Arity) {
 540                                                 better_type = IsImportedTypeOverride (ts, found);
 541                                                 if (better_type == found)
 542                                                         return;
 543
 544                                                 if (better_type != null) {
 545                                                         existing [0] = better_type;
 546                                                         return;
 547                                                 }
 548                                         }
 549
 550                                         existing = new List<TypeSpec> ();
 551                                         existing.Add (found);
 552                                         types[name] = existing;
 553                                 } else {
 554                                         for (int i = 0; i < existing.Count; ++i) {
 555                                                 found = existing[i];
 556                                                 if (ts.Arity != found.Arity)
 557                                                         continue;
 558
 559                                                 better_type = IsImportedTypeOverride (ts, found);
 560                                                 if (better_type == found)
 561                                                         return;
 562
 563                                                 if (better_type != null) {
 564                                                         existing.RemoveAt (i);
 565                                                         --i;
 566                                                         continue;
 567                                                 }
 568                                         }
 569                                 }
 570
 571                                 existing.Add (ts);
 572                         } else {
 573                                 types.Add (name, new TypeSpec[] { ts });
 574                         }
 575                 }
 576
 577                 //
 578                 // We import any types but in the situation there are same types
 579                 // but one has better visibility (either public or internal with friend)
 580                 // the less visible type is removed from the namespace cache
 581                 //
 582                 public static TypeSpec IsImportedTypeOverride (TypeSpec ts, TypeSpec found)
 583                 {
 584                         var ts_accessible = (ts.Modifiers & Modifiers.PUBLIC) != 0 || TypeManager.IsThisOrFriendAssembly (CodeGen.Assembly.Builder, ts.MemberDefinition.Assembly);
 585                         var found_accessible = (found.Modifiers & Modifiers.PUBLIC) != 0 || TypeManager.IsThisOrFriendAssembly (CodeGen.Assembly.Builder, found.MemberDefinition.Assembly);
 586
 587                         if (ts_accessible && !found_accessible)
 588                                 return ts;
 589
 590                         // found is better always better for accessible or inaccessible ts
 591                         if (!ts_accessible)
 592                                 return found;
 593
 594                         return null;
 595                 }
 596
 597                 public void RemoveDeclSpace (string name)
 598                 {
 599                         types.Remove (name);
 600                 }
 601
 602                 public void ReplaceTypeWithPredefined (TypeSpec ts, PredefinedTypeSpec pts)
 603                 {
 604                         var found = types [ts.Name];
 605                         cached_types.Remove (ts.Name);
 606                         if (found.Count == 1) {
 607                                 types[ts.Name][0] = pts;
 608                         } else {
 609                                 throw new NotImplementedException ();
 610                         }
 611                 }
 612
 613                 public void VerifyClsCompliance ()
 614                 {
 615                         if (types == null || cls_checked)
 616                                 return;
 617
 618                         cls_checked = true;
 619
 620                         // TODO: This is quite ugly way to check for CLS compliance at namespace level
 621
 622                         var locase_types = new Dictionary<string, List<TypeSpec>> (StringComparer.OrdinalIgnoreCase);
 623                         foreach (var tgroup in types.Values) {
 624                                 foreach (var tm in tgroup) {
 625                                         if ((tm.Modifiers & Modifiers.PUBLIC) == 0 || !tm.IsCLSCompliant ())
 626                                                 continue;
 627
 628                                         List<TypeSpec> found;
 629                                         if (!locase_types.TryGetValue (tm.Name, out found)) {
 630                                                 found = new List<TypeSpec> ();
 631                                                 locase_types.Add (tm.Name, found);
 632                                         }
 633
 634                                         found.Add (tm);
 635                                 }
 636                         }
 637
 638                         foreach (var locase in locase_types.Values) {
 639                                 if (locase.Count < 2)
 640                                         continue;
 641
 642                                 bool all_same = true;
 643                                 foreach (var notcompliant in locase) {
 644                                         all_same = notcompliant.Name == locase[0].Name;
 645                                         if (!all_same)
 646                                                 break;
 647                                 }
 648
 649                                 if (all_same)
 650                                         continue;
 651
 652                                 TypeContainer compiled = null;
 653                                 foreach (var notcompliant in locase) {
 654                                         if (!notcompliant.MemberDefinition.IsImported) {
 655                                                 if (compiled != null)
 656                                                         compiled.Compiler.Report.SymbolRelatedToPreviousError (compiled);
 657
 658                                                 compiled = notcompliant.MemberDefinition as TypeContainer;
 659                                         } else {
 660                                                 compiled.Compiler.Report.SymbolRelatedToPreviousError (notcompliant);
 661                                         }
 662                                 }
 663
 664                                 compiled.Compiler.Report.Warning (3005, 1, compiled.Location,
 665                                         "Identifier `{0}' differing only in case is not CLS-compliant", compiled.GetSignatureForError ());
 666                         }
 667                 }
 668         }
 669
 670         //
 671         // Namespace container as created by the parser
 672         //
 673         public class NamespaceEntry : IMemberContext {
 674
 675                 public class UsingEntry {
 676                         readonly MemberName name;
 677                         Namespace resolved;
 678
 679                         public UsingEntry (MemberName name)
 680                         {
 681                                 this.name = name;
 682                         }
 683
 684                         public string GetSignatureForError ()
 685                         {
 686                                 return name.GetSignatureForError ();
 687                         }
 688
 689                         public Location Location {
 690                                 get { return name.Location; }
 691                         }
 692
 693                         public MemberName MemberName {
 694                                 get { return name; }
 695                         }
 696
 697                         public string Name {
 698                                 get { return GetSignatureForError (); }
 699                         }
 700
 701                         public Namespace Resolve (IMemberContext rc)
 702                         {
 703                                 if (resolved != null)
 704                                         return resolved;
 705
 706                                 FullNamedExpression fne = name.GetTypeExpression ().ResolveAsTypeStep (rc, false);
 707                                 if (fne == null)
 708                                         return null;
 709
 710                                 resolved = fne as Namespace;
 711                                 if (resolved == null) {
 712                                         rc.Compiler.Report.SymbolRelatedToPreviousError (fne.Type);
 713                                         rc.Compiler.Report.Error (138, Location,
 714                                                 "`{0}' is a type not a namespace. A using namespace directive can only be applied to namespaces",
 715                                                 GetSignatureForError ());
 716                                 }
 717                                 return resolved;
 718                         }
 719
 720                         public override string ToString ()
 721                         {
 722                                 return Name;
 723                         }
 724                 }
 725
 726                 public class UsingAliasEntry {
 727                         public readonly string Alias;
 728                         public Location Location;
 729
 730                         public UsingAliasEntry (string alias, Location loc)
 731                         {
 732                                 this.Alias = alias;
 733                                 this.Location = loc;
 734                         }
 735
 736                         public virtual FullNamedExpression Resolve (IMemberContext rc)
 737                         {
 738                                 FullNamedExpression fne = GlobalRootNamespace.Instance.GetRootNamespace (Alias);
 739                                 if (fne == null) {
 740                                         rc.Compiler.Report.Error (430, Location,
 741                                                 "The extern alias `{0}' was not specified in -reference option",
 742                                                 Alias);
 743                                 }
 744
 745                                 return fne;
 746                         }
 747
 748                         public override string ToString ()
 749                         {
 750                                 return Alias;
 751                         }
 752
 753                 }
 754
 755                 class LocalUsingAliasEntry : UsingAliasEntry {
 756                         FullNamedExpression resolved;
 757                         MemberName value;
 758
 759                         public LocalUsingAliasEntry (string alias, MemberName name, Location loc)
 760                                 : base (alias, loc)
 761                         {
 762                                 this.value = name;
 763                         }
 764
 765                         public override FullNamedExpression Resolve (IMemberContext rc)
 766                         {
 767                                 if (resolved != null || value == null)
 768                                         return resolved;
 769
 770                                 if (rc == null)
 771                                         return null;
 772
 773                                 resolved = value.GetTypeExpression ().ResolveAsTypeStep (rc, false);
 774                                 if (resolved == null) {
 775                                         value = null;
 776                                         return null;
 777                                 }
 778
 779                                 if (resolved is TypeExpr)
 780                                         resolved = resolved.ResolveAsTypeTerminal (rc, false);
 781
 782                                 return resolved;
 783                         }
 784
 785                         public override string ToString ()
 786                         {
 787                                 return String.Format ("{0} = {1}", Alias, value.GetSignatureForError ());
 788                         }
 789                 }
 790
 791                 Namespace ns;
 792                 NamespaceEntry parent, implicit_parent;
 793                 CompilationUnit file;
 794                 int symfile_id;
 795
 796                 // Namespace using import block
 797                 List<UsingAliasEntry> using_aliases;
 798                 List<UsingEntry> using_clauses;
 799                 public bool DeclarationFound;
 800                 // End
 801
 802                 public readonly bool IsImplicit;
 803                 public readonly DeclSpace SlaveDeclSpace;
 804                 static readonly Namespace [] empty_namespaces = new Namespace [0];
 805                 Namespace [] namespace_using_table;
 806
 807                 static List<NamespaceEntry> entries = new List<NamespaceEntry> ();
 808
 809                 public static void Reset ()
 810                 {
 811                         entries = new List<NamespaceEntry> ();
 812                 }
 813
 814                 public NamespaceEntry (NamespaceEntry parent, CompilationUnit file, string name)
 815                 {
 816                         this.parent = parent;
 817                         this.file = file;
 818                         entries.Add (this);
 819
 820                         if (parent != null)
 821                                 ns = parent.NS.GetNamespace (name, true);
 822                         else if (name != null)
 823                                 ns = GlobalRootNamespace.Instance.GetNamespace (name, true);
 824                         else
 825                                 ns = GlobalRootNamespace.Instance;
 826                         SlaveDeclSpace = new RootDeclSpace (this);
 827                 }
 828
 829                 private NamespaceEntry (NamespaceEntry parent, CompilationUnit file, Namespace ns, bool slave)
 830                 {
 831                         this.parent = parent;
 832                         this.file = file;
 833                         this.IsImplicit = true;
 834                         this.ns = ns;
 835                         this.SlaveDeclSpace = slave ? new RootDeclSpace (this) : null;
 836                 }
 837
 838                 //
 839                 // Populates the Namespace with some using declarations, used by the
 840                 // eval mode.
 841                 //
 842                 public void Populate (List<UsingAliasEntry> source_using_aliases, List<UsingEntry> source_using_clauses)
 843                 {
 844                         foreach (UsingAliasEntry uae in source_using_aliases){
 845                                 if (using_aliases == null)
 846                                         using_aliases = new List<UsingAliasEntry> ();
 847
 848                                 using_aliases.Add (uae);
 849                         }
 850
 851                         foreach (UsingEntry ue in source_using_clauses){
 852                                 if (using_clauses == null)
 853                                         using_clauses = new List<UsingEntry> ();
 854
 855                                 using_clauses.Add (ue);
 856                         }
 857                 }
 858
 859                 //
 860                 // Extracts the using alises and using clauses into a couple of
 861                 // arrays that might already have the same information;  Used by the
 862                 // C# Eval mode.
 863                 //
 864                 public void Extract (List<UsingAliasEntry> out_using_aliases, List<UsingEntry> out_using_clauses)
 865                 {
 866                         if (using_aliases != null){
 867                                 foreach (UsingAliasEntry uae in using_aliases){
 868                                         bool replaced = false;
 869
 870                                         for (int i = 0; i < out_using_aliases.Count; i++){
 871                                                 UsingAliasEntry out_uea = (UsingAliasEntry) out_using_aliases [i];
 872
 873                                                 if (out_uea.Alias == uae.Alias){
 874                                                         out_using_aliases [i] = uae;
 875                                                         replaced = true;
 876                                                         break;
 877                                                 }
 878                                         }
 879                                         if (!replaced)
 880                                                 out_using_aliases.Add (uae);
 881                                 }
 882                         }
 883
 884                         if (using_clauses != null){
 885                                 foreach (UsingEntry ue in using_clauses){
 886                                         bool found = false;
 887
 888                                         foreach (UsingEntry out_ue in out_using_clauses)
 889                                                 if (out_ue.Name == ue.Name){
 890                                                         found = true;
 891                                                         break;
 892                                                 }
 893                                         if (!found)
 894                                                 out_using_clauses.Add (ue);
 895                                 }
 896                         }
 897                 }
 898
 899                 //
 900                 // According to section 16.3.1 (using-alias-directive), the namespace-or-type-name is
 901                 // resolved as if the immediately containing namespace body has no using-directives.
 902                 //
 903                 // Section 16.3.2 says that the same rule is applied when resolving the namespace-name
 904                 // in the using-namespace-directive.
 905                 //
 906                 // To implement these rules, the expressions in the using directives are resolved using
 907                 // the "doppelganger" (ghostly bodiless duplicate).
 908                 //
 909                 NamespaceEntry doppelganger;
 910                 NamespaceEntry Doppelganger {
 911                         get {
 912                                 if (!IsImplicit && doppelganger == null) {
 913                                         doppelganger = new NamespaceEntry (ImplicitParent, file, ns, true);
 914                                         doppelganger.using_aliases = using_aliases;
 915                                 }
 916                                 return doppelganger;
 917                         }
 918                 }
 919
 920                 public Namespace NS {
 921                         get { return ns; }
 922                 }
 923
 924                 public NamespaceEntry Parent {
 925                         get { return parent; }
 926                 }
 927
 928                 public NamespaceEntry ImplicitParent {
 929                         get {
 930                                 if (parent == null)
 931                                         return null;
 932                                 if (implicit_parent == null) {
 933                                         implicit_parent = (parent.NS == ns.Parent)
 934                                                 ? parent
 935                                                 : new NamespaceEntry (parent, file, ns.Parent, false);
 936                                 }
 937                                 return implicit_parent;
 938                         }
 939                 }
 940
 941                 /// <summary>
 942                 ///   Records a new namespace for resolving name references
 943                 /// </summary>
 944                 public void AddUsing (MemberName name, Location loc)
 945                 {
 946                         if (DeclarationFound){
 947                                 Compiler.Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
 948                         }
 949
 950                         if (using_clauses == null) {
 951                                 using_clauses = new List<UsingEntry> ();
 952                         } else {
 953                                 foreach (UsingEntry old_entry in using_clauses) {
 954                                         if (name.Equals (old_entry.MemberName)) {
 955                                                 Compiler.Report.SymbolRelatedToPreviousError (old_entry.Location, old_entry.GetSignatureForError ());
 956                                                 Compiler.Report.Warning (105, 3, loc, "The using directive for `{0}' appeared previously in this namespace", name.GetSignatureForError ());
 957                                                 return;
 958                                         }
 959                                 }
 960                         }
 961
 962                         using_clauses.Add (new UsingEntry (name));
 963                 }
 964
 965                 public void AddUsingAlias (string alias, MemberName name, Location loc)
 966                 {
 967                         // TODO: This is parser bussines
 968                         if (DeclarationFound){
 969                                 Compiler.Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
 970                         }
 971
 972                         if (RootContext.Version != LanguageVersion.ISO_1 && alias == "global")
 973                                 Compiler.Report.Warning (440, 2, loc, "An alias named `global' will not be used when resolving 'global::';" +
 974                                         " the global namespace will be used instead");
 975
 976                         AddUsingAlias (new LocalUsingAliasEntry (alias, name, loc));
 977                 }
 978
 979                 public void AddUsingExternalAlias (string alias, Location loc, Report Report)
 980                 {
 981                         // TODO: Do this in parser
 982                         bool not_first = using_clauses != null || DeclarationFound;
 983                         if (using_aliases != null && !not_first) {
 984                                 foreach (UsingAliasEntry uae in using_aliases) {
 985                                         if (uae is LocalUsingAliasEntry) {
 986                                                 not_first = true;
 987                                                 break;
 988                                         }
 989                                 }
 990                         }
 991
 992                         if (not_first)
 993                                 Report.Error (439, loc, "An extern alias declaration must precede all other elements");
 994
 995                         if (alias == "global") {
 996                                 Error_GlobalNamespaceRedefined (loc, Report);
 997                                 return;
 998                         }
 999
1000                         AddUsingAlias (new UsingAliasEntry (alias, loc));
1001                 }
1002
1003                 void AddUsingAlias (UsingAliasEntry uae)
1004                 {
1005                         if (using_aliases == null) {
1006                                 using_aliases = new List<UsingAliasEntry> ();
1007                         } else {
1008                                 foreach (UsingAliasEntry entry in using_aliases) {
1009                                         if (uae.Alias == entry.Alias) {
1010                                                 Compiler.Report.SymbolRelatedToPreviousError (uae.Location, uae.Alias);
1011                                                 Compiler.Report.Error (1537, entry.Location, "The using alias `{0}' appeared previously in this namespace",
1012                                                         entry.Alias);
1013                                                 return;
1014                                         }
1015                                 }
1016                         }
1017
1018                         using_aliases.Add (uae);
1019                 }
1020
1021                 ///
1022                 /// Does extension methods look up to find a method which matches name and extensionType.
1023                 /// Search starts from this namespace and continues hierarchically up to top level.
1024                 ///
1025                 public ExtensionMethodGroupExpr LookupExtensionMethod (TypeSpec extensionType, string name, int arity, Location loc)
1026                 {
1027                         List<MethodSpec> candidates = null;
1028                         foreach (Namespace n in GetUsingTable ()) {
1029                                 var a = n.LookupExtensionMethod (extensionType, null, name, arity);
1030                                 if (a == null)
1031                                         continue;
1032
1033                                 if (candidates == null)
1034                                         candidates = a;
1035                                 else
1036                                         candidates.AddRange (a);
1037                         }
1038
1039                         if (candidates != null)
1040                                 return new ExtensionMethodGroupExpr (candidates, parent, extensionType, loc);
1041
1042                         if (parent == null)
1043                                 return null;
1044
1045                         //
1046                         // Inspect parent namespaces in namespace expression
1047                         //
1048                         Namespace parent_ns = ns.Parent;
1049                         do {
1050                                 candidates = parent_ns.LookupExtensionMethod (extensionType, null, name, arity);
1051                                 if (candidates != null)
1052                                         return new ExtensionMethodGroupExpr (candidates, parent, extensionType, loc);
1053
1054                                 parent_ns = parent_ns.Parent;
1055                         } while (parent_ns != null);
1056
1057                         //
1058                         // Continue in parent scope
1059                         //
1060                         return parent.LookupExtensionMethod (extensionType, name, arity, loc);
1061                 }
1062
1063                 public FullNamedExpression LookupNamespaceOrType (string name, int arity, Location loc, bool ignore_cs0104)
1064                 {
1065                         // Precondition: Only simple names (no dots) will be looked up with this function.
1066                         FullNamedExpression resolved = null;
1067                         for (NamespaceEntry curr_ns = this; curr_ns != null; curr_ns = curr_ns.ImplicitParent) {
1068                                 if ((resolved = curr_ns.Lookup (name, arity, loc, ignore_cs0104)) != null)
1069                                         break;
1070                         }
1071
1072                         return resolved;
1073                 }
1074
1075                 public IList<string> CompletionGetTypesStartingWith (string prefix)
1076                 {
1077                         IEnumerable<string> all = Enumerable.Empty<string> ();
1078
1079                         for (NamespaceEntry curr_ns = this; curr_ns != null; curr_ns = curr_ns.ImplicitParent){
1080                                 foreach (Namespace using_ns in GetUsingTable ()){
1081                                         if (prefix.StartsWith (using_ns.Name)){
1082                                                 int ld = prefix.LastIndexOf ('.');
1083                                                 if (ld != -1){
1084                                                         string rest = prefix.Substring (ld+1);
1085
1086                                                         all = all.Concat (using_ns.CompletionGetTypesStartingWith (rest));
1087                                                 }
1088                                         }
1089                                         all = all.Concat (using_ns.CompletionGetTypesStartingWith (prefix));
1090                                 }
1091                         }
1092
1093                         return all.Distinct ().ToList ();
1094                 }
1095
1096                 // Looks-up a alias named @name in this and surrounding namespace declarations
1097                 public FullNamedExpression LookupNamespaceAlias (string name)
1098                 {
1099                         for (NamespaceEntry n = this; n != null; n = n.ImplicitParent) {
1100                                 if (n.using_aliases == null)
1101                                         continue;
1102
1103                                 foreach (UsingAliasEntry ue in n.using_aliases) {
1104                                         if (ue.Alias == name)
1105                                                 return ue.Resolve (Doppelganger);
1106                                 }
1107                         }
1108
1109                         return null;
1110                 }
1111
1112                 private FullNamedExpression Lookup (string name, int arity, Location loc, bool ignore_cs0104)
1113                 {
1114                         //
1115                         // Check whether it's in the namespace.
1116                         //
1117                         FullNamedExpression fne = ns.Lookup (Compiler, name, arity, loc);
1118
1119                         //
1120                         // Check aliases.
1121                         //
1122                         if (using_aliases != null && arity == 0) {
1123                                 foreach (UsingAliasEntry ue in using_aliases) {
1124                                         if (ue.Alias == name) {
1125                                                 if (fne != null) {
1126                                                         if (Doppelganger != null) {
1127                                                                 // TODO: Namespace has broken location
1128                                                                 //Report.SymbolRelatedToPreviousError (fne.Location, null);
1129                                                                 Compiler.Report.SymbolRelatedToPreviousError (ue.Location, null);
1130                                                                 Compiler.Report.Error (576, loc,
1131                                                                         "Namespace `{0}' contains a definition with same name as alias `{1}'",
1132                                                                         GetSignatureForError (), name);
1133                                                         } else {
1134                                                                 return fne;
1135                                                         }
1136                                                 }
1137
1138                                                 return ue.Resolve (Doppelganger);
1139                                         }
1140                                 }
1141                         }
1142
1143                         if (fne != null) {
1144                                 if (!((fne.Type.Modifiers & Modifiers.INTERNAL) != 0 && !TypeManager.IsThisOrFriendAssembly (CodeGen.Assembly.Builder, fne.Type.Assembly)))
1145                                         return fne;
1146                         }
1147
1148                         if (IsImplicit)
1149                                 return null;
1150
1151                         //
1152                         // Check using entries.
1153                         //
1154                         FullNamedExpression match = null;
1155                         foreach (Namespace using_ns in GetUsingTable ()) {
1156                                 // A using directive imports only types contained in the namespace, it
1157                                 // does not import any nested namespaces
1158                                 fne = using_ns.LookupType (Compiler, name, arity, loc);
1159                                 if (fne == null)
1160                                         continue;
1161
1162                                 if (match == null) {
1163                                         match = fne;
1164                                         continue;
1165                                 }
1166
1167                                 // Prefer types over namespaces
1168                                 var texpr_fne = fne as TypeExpr;
1169                                 var texpr_match = match as TypeExpr;
1170                                 if (texpr_fne != null && texpr_match == null) {
1171                                         match = fne;
1172                                         continue;
1173                                 } else if (texpr_fne == null) {
1174                                         continue;
1175                                 }
1176
1177                                 if (ignore_cs0104)
1178                                         return match;
1179
1180                                 // It can be top level accessibility only
1181                                 var better = Namespace.IsImportedTypeOverride (texpr_match.Type, texpr_fne.Type);
1182                                 if (better == null) {
1183                                         Compiler.Report.SymbolRelatedToPreviousError (texpr_match.Type);
1184                                         Compiler.Report.SymbolRelatedToPreviousError (texpr_fne.Type);
1185                                         Compiler.Report.Error (104, loc, "`{0}' is an ambiguous reference between `{1}' and `{2}'",
1186                                                 name, texpr_match.GetSignatureForError (), texpr_fne.GetSignatureForError ());
1187                                         return match;
1188                                 }
1189
1190                                 if (better == texpr_fne.Type)
1191                                         match = texpr_fne;
1192                         }
1193
1194                         return match;
1195                 }
1196
1197                 Namespace [] GetUsingTable ()
1198                 {
1199                         if (namespace_using_table != null)
1200                                 return namespace_using_table;
1201
1202                         if (using_clauses == null) {
1203                                 namespace_using_table = empty_namespaces;
1204                                 return namespace_using_table;
1205                         }
1206
1207                         var list = new List<Namespace> (using_clauses.Count);
1208
1209                         foreach (UsingEntry ue in using_clauses) {
1210                                 Namespace using_ns = ue.Resolve (Doppelganger);
1211                                 if (using_ns == null)
1212                                         continue;
1213
1214                                 list.Add (using_ns);
1215                         }
1216
1217                         namespace_using_table = list.ToArray ();
1218                         return namespace_using_table;
1219                 }
1220
1221                 static readonly string [] empty_using_list = new string [0];
1222
1223                 public int SymbolFileID {
1224                         get {
1225                                 if (symfile_id == 0 && file.SourceFileEntry != null) {
1226                                         int parent_id = parent == null ? 0 : parent.SymbolFileID;
1227
1228                                         string [] using_list = empty_using_list;
1229                                         if (using_clauses != null) {
1230                                                 using_list = new string [using_clauses.Count];
1231                                                 for (int i = 0; i < using_clauses.Count; i++)
1232                                                         using_list [i] = ((UsingEntry) using_clauses [i]).MemberName.GetName ();
1233                                         }
1234
1235                                         symfile_id = SymbolWriter.DefineNamespace (ns.Name, file.CompileUnitEntry, using_list, parent_id);
1236                                 }
1237                                 return symfile_id;
1238                         }
1239                 }
1240
1241                 static void MsgtryRef (string s)
1242                 {
1243                         Console.WriteLine ("    Try using -r:" + s);
1244                 }
1245
1246                 static void MsgtryPkg (string s)
1247                 {
1248                         Console.WriteLine ("    Try using -pkg:" + s);
1249                 }
1250
1251                 public static void Error_GlobalNamespaceRedefined (Location loc, Report Report)
1252                 {
1253                         Report.Error (1681, loc, "You cannot redefine the global extern alias");
1254                 }
1255
1256                 public static void Error_NamespaceNotFound (Location loc, string name, Report Report)
1257                 {
1258                         Report.Error (246, loc, "The type or namespace name `{0}' could not be found. Are you missing a using directive or an assembly reference?",
1259                                 name);
1260
1261                         switch (name) {
1262                         case "Gtk": case "GtkSharp":
1263                                 MsgtryPkg ("gtk-sharp");
1264                                 break;
1265
1266                         case "Gdk": case "GdkSharp":
1267                                 MsgtryPkg ("gdk-sharp");
1268                                 break;
1269
1270                         case "Glade": case "GladeSharp":
1271                                 MsgtryPkg ("glade-sharp");
1272                                 break;
1273
1274                         case "System.Drawing":
1275                         case "System.Web.Services":
1276                         case "System.Web":
1277                         case "System.Data":
1278                         case "System.Windows.Forms":
1279                                 MsgtryRef (name);
1280                                 break;
1281                         }
1282                 }
1283
1284                 /// <summary>
1285                 ///   Used to validate that all the using clauses are correct
1286                 ///   after we are finished parsing all the files.
1287                 /// </summary>
1288                 void VerifyUsing ()
1289                 {
1290                         if (using_aliases != null) {
1291                                 foreach (UsingAliasEntry ue in using_aliases)
1292                                         ue.Resolve (Doppelganger);
1293                         }
1294
1295                         if (using_clauses != null) {
1296                                 foreach (UsingEntry ue in using_clauses)
1297                                         ue.Resolve (Doppelganger);
1298                         }
1299                 }
1300
1301                 /// <summary>
1302                 ///   Used to validate that all the using clauses are correct
1303                 ///   after we are finished parsing all the files.
1304                 /// </summary>
1305                 static public void VerifyAllUsing ()
1306                 {
1307                         foreach (NamespaceEntry entry in entries)
1308                                 entry.VerifyUsing ();
1309                 }
1310
1311                 public string GetSignatureForError ()
1312                 {
1313                         return ns.GetSignatureForError ();
1314                 }
1315
1316                 public override string ToString ()
1317                 {
1318                         return ns.ToString ();
1319                 }
1320
1321                 #region IMemberContext Members
1322
1323                 public CompilerContext Compiler {
1324                         get { return RootContext.ToplevelTypes.Compiler; }
1325                 }
1326
1327                 public TypeSpec CurrentType {
1328                         get { return SlaveDeclSpace.CurrentType; }
1329                 }
1330
1331                 public MemberCore CurrentMemberDefinition {
1332                         get { return SlaveDeclSpace.CurrentMemberDefinition; }
1333                 }
1334
1335                 public TypeParameter[] CurrentTypeParameters {
1336                         get { return SlaveDeclSpace.CurrentTypeParameters; }
1337                 }
1338
1339                 // FIXME: It's false for expression types
1340                 public bool HasUnresolvedConstraints {
1341                         get { return true; }
1342                 }
1343
1344                 public bool IsObsolete {
1345                         get { return SlaveDeclSpace.IsObsolete; }
1346                 }
1347
1348                 public bool IsUnsafe {
1349                         get { return SlaveDeclSpace.IsUnsafe; }
1350                 }
1351
1352                 public bool IsStatic {
1353                         get { return SlaveDeclSpace.IsStatic; }
1354                 }
1355
1356                 #endregion
1357         }
1358 }