mcs/mcs/namespace.cs

   1 //
   2 // namespace.cs: Tracks namespaces
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //
   7 // (C) 2001 Ximian, Inc.
   8 //
   9 using System;
  10 using System.Collections;
  11
  12 namespace Mono.CSharp {
  13
  14         /// <summary>
  15         ///   Keeps track of the namespaces defined in the C# code.
  16         ///
  17         ///   This is an Expression to allow it to be referenced in the
  18         ///   compiler parse/intermediate tree during name resolution.
  19         /// </summary>
  20         public class Namespace : FullNamedExpression, IAlias {
  21                 static ArrayList all_namespaces = new ArrayList ();
  22                 static Hashtable namespaces_map = new Hashtable ();
  23
  24                 Namespace parent;
  25                 string fullname;
  26                 ArrayList entries;
  27                 Hashtable namespaces;
  28                 Hashtable defined_names;
  29
  30                 /// <summary>
  31                 ///   Constructor Takes the current namespace and the
  32                 ///   name.  This is bootstrapped with parent == null
  33                 ///   and name = ""
  34                 /// </summary>
  35                 public Namespace (Namespace parent, string name)
  36                 {
  37                         // Expression members.
  38                         this.eclass = ExprClass.Namespace;
  39                         this.Type = null;
  40                         this.loc = Location.Null;
  41
  42                         this.parent = parent;
  43
  44                         string pname = parent != null ? parent.Name : "";
  45
  46                         if (pname == "")
  47                                 fullname = name;
  48                         else
  49                                 fullname = parent.Name + "." + name;
  50
  51                         entries = new ArrayList ();
  52                         namespaces = new Hashtable ();
  53                         defined_names = new Hashtable ();
  54
  55                         all_namespaces.Add (this);
  56                         if (namespaces_map.Contains (fullname))
  57                                 return;
  58                         namespaces_map [fullname] = true;
  59                 }
  60
  61                 public override Expression DoResolve (EmitContext ec)
  62                 {
  63                         return this;
  64                 }
  65
  66                 public override void Emit (EmitContext ec)
  67                 {
  68                         throw new InternalErrorException ("Expression tree referenced namespace " + fullname + " during Emit ()");
  69                 }
  70
  71                 public static bool IsNamespace (string name)
  72                 {
  73                         return namespaces_map [name] != null;
  74                 }
  75
  76                 public static Namespace Root = new Namespace (null, "");
  77
  78                 public Namespace GetNamespace (string name, bool create)
  79                 {
  80                         int pos = name.IndexOf ('.');
  81
  82                         Namespace ns;
  83                         string first;
  84                         if (pos >= 0)
  85                                 first = name.Substring (0, pos);
  86                         else
  87                                 first = name;
  88
  89                         ns = (Namespace) namespaces [first];
  90                         if (ns == null) {
  91                                 if (!create)
  92                                         return null;
  93
  94                                 ns = new Namespace (this, first);
  95                                 namespaces.Add (first, ns);
  96                         }
  97
  98                         if (pos >= 0)
  99                                 ns = ns.GetNamespace (name.Substring (pos + 1), create);
 100
 101                         return ns;
 102                 }
 103
 104                 public static Namespace LookupNamespace (string name, bool create)
 105                 {
 106                         return Root.GetNamespace (name, create);
 107                 }
 108
 109                 public FullNamedExpression Lookup (DeclSpace ds, string name, Location loc)
 110                 {
 111                         IAlias o = (IAlias) defined_names [name];
 112
 113                         Type t;
 114                         DeclSpace tdecl = o as DeclSpace;
 115                         if (tdecl != null) {
 116                                 t = tdecl.DefineType ();
 117
 118                                 if ((ds == null) || ds.CheckAccessLevel (t))
 119                                         return new TypeExpression (t, Location.Null);
 120                         }
 121
 122                         Namespace ns = GetNamespace (name, false);
 123                         if (ns != null)
 124                                 return ns;
 125
 126                         t = TypeManager.LookupType (DeclSpace.MakeFQN (fullname, name));
 127                         if ((t == null) || ((ds != null) && !ds.CheckAccessLevel (t)))
 128                                 return null;
 129
 130                         return new TypeExpression (t, Location.Null);
 131                 }
 132
 133                 public void AddNamespaceEntry (NamespaceEntry entry)
 134                 {
 135                         entries.Add (entry);
 136                 }
 137
 138                 public void DefineName (string name, IAlias o)
 139                 {
 140                         defined_names.Add (name, o);
 141                 }
 142
 143                 static public ArrayList UserDefinedNamespaces {
 144                         get {
 145                                 return all_namespaces;
 146                         }
 147                 }
 148
 149                 /// <summary>
 150                 ///   The qualified name of the current namespace
 151                 /// </summary>
 152                 public string Name {
 153                         get {
 154                                 return fullname;
 155                         }
 156                 }
 157
 158                 public override string FullName {
 159                         get {
 160                                 return fullname;
 161                         }
 162                 }
 163
 164                 /// <summary>
 165                 ///   The parent of this namespace, used by the parser to "Pop"
 166                 ///   the current namespace declaration
 167                 /// </summary>
 168                 public Namespace Parent {
 169                         get {
 170                                 return parent;
 171                         }
 172                 }
 173
 174                 public static void DefineNamespaces (SymbolWriter symwriter)
 175                 {
 176                         foreach (Namespace ns in all_namespaces) {
 177                                 foreach (NamespaceEntry entry in ns.entries)
 178                                         entry.DefineNamespace (symwriter);
 179                         }
 180                 }
 181
 182                 /// <summary>
 183                 ///   Used to validate that all the using clauses are correct
 184                 ///   after we are finished parsing all the files.
 185                 /// </summary>
 186                 public static void VerifyUsing ()
 187                 {
 188                         foreach (Namespace ns in all_namespaces) {
 189                                 foreach (NamespaceEntry entry in ns.entries)
 190                                         entry.VerifyUsing ();
 191                         }
 192                 }
 193
 194                 public override string ToString ()
 195                 {
 196                         if (this == Root)
 197                                 return "Namespace (<root>)";
 198                         else
 199                                 return String.Format ("Namespace ({0})", Name);
 200                 }
 201
 202                 bool IAlias.IsType {
 203                         get { return false; }
 204                 }
 205
 206                 TypeExpr IAlias.ResolveAsType (EmitContext ec)
 207                 {
 208                         throw new InvalidOperationException ();
 209                 }
 210         }
 211
 212         public class NamespaceEntry
 213         {
 214                 Namespace ns;
 215                 NamespaceEntry parent, implicit_parent;
 216                 SourceFile file;
 217                 int symfile_id;
 218                 Hashtable aliases;
 219                 ArrayList using_clauses;
 220                 public bool DeclarationFound = false;
 221
 222                 //
 223                 // This class holds the location where a using definition is
 224                 // done, and whether it has been used by the program or not.
 225                 //
 226                 // We use this to flag using clauses for namespaces that do not
 227                 // exist.
 228                 //
 229                 public class UsingEntry {
 230                         public Expression Name;
 231                         public readonly NamespaceEntry NamespaceEntry;
 232                         public readonly Location Location;
 233
 234                         public UsingEntry (NamespaceEntry entry, Expression name, Location loc)
 235                         {
 236                                 Name = name;
 237                                 NamespaceEntry = entry;
 238                                 Location = loc;
 239                         }
 240
 241                         internal FullNamedExpression resolved;
 242
 243                         public Namespace Resolve ()
 244                         {
 245                                 if (resolved != null)
 246                                         return resolved as Namespace;
 247
 248                                 DeclSpace root = RootContext.Tree.Types;
 249                                 root.NamespaceEntry = NamespaceEntry;
 250                                 resolved = Name.ResolveAsTypeStep (root.EmitContext);
 251                                 root.NamespaceEntry = null;
 252
 253                                 return resolved as Namespace;
 254                         }
 255                 }
 256
 257                 public class AliasEntry {
 258                         public readonly string Name;
 259                         public readonly Expression Alias;
 260                         public readonly NamespaceEntry NamespaceEntry;
 261                         public readonly Location Location;
 262
 263                         public AliasEntry (NamespaceEntry entry, string name, Expression alias, Location loc)
 264                         {
 265                                 Name = name;
 266                                 Alias = alias;
 267                                 NamespaceEntry = entry;
 268                                 Location = loc;
 269                         }
 270
 271                         FullNamedExpression resolved;
 272
 273                         public FullNamedExpression Resolve ()
 274                         {
 275                                 if (resolved != null)
 276                                         return resolved;
 277
 278                                 DeclSpace root = RootContext.Tree.Types;
 279                                 root.NamespaceEntry = NamespaceEntry;
 280                                 resolved = Alias.ResolveAsTypeStep (root.EmitContext);
 281                                 root.NamespaceEntry = null;
 282
 283                                 return resolved;
 284                         }
 285                 }
 286
 287                 public NamespaceEntry (NamespaceEntry parent, SourceFile file, string name, Location loc)
 288                 {
 289                         this.parent = parent;
 290                         this.file = file;
 291                         this.IsImplicit = false;
 292                         this.ID = ++next_id;
 293
 294                         if (parent != null)
 295                                 ns = parent.NS.GetNamespace (name, true);
 296                         else if (name != null)
 297                                 ns = Namespace.LookupNamespace (name, true);
 298                         else
 299                                 ns = Namespace.Root;
 300                         ns.AddNamespaceEntry (this);
 301                         this.FullName = ns.Name;
 302                 }
 303
 304
 305                 private NamespaceEntry (NamespaceEntry parent, SourceFile file, Namespace ns)
 306                 {
 307                         this.parent = parent;
 308                         this.file = file;
 309                         this.IsImplicit = true;
 310                         this.ID = ++next_id;
 311                         this.ns = ns;
 312                         this.FullName = ns.Name;
 313                 }
 314
 315                 //
 316                 // According to section 16.3.1 (using-alias-directive), the namespace-or-type-name is
 317                 // resolved as if the immediately containing namespace body has no using-directives.
 318                 //
 319                 // Section 16.3.2 says that the same rule is applied when resolving the namespace-name
 320                 // in the using-namespace-directive.
 321                 //
 322                 // To implement these rules, the expressions in the using directives are resolved using
 323                 // the "doppelganger" (ghostly bodiless duplicate).
 324                 //
 325                 NamespaceEntry doppelganger;
 326                 NamespaceEntry Doppelganger {
 327                         get {
 328                                 if (!IsImplicit && doppelganger == null)
 329                                         doppelganger = new NamespaceEntry (ImplicitParent, file, ns);
 330                                 return doppelganger;
 331                         }
 332                 }
 333
 334                 static int next_id = 0;
 335                 public readonly string FullName;
 336                 public readonly int ID;
 337                 public readonly bool IsImplicit;
 338
 339                 public Namespace NS {
 340                         get {
 341                                 return ns;
 342                         }
 343                 }
 344
 345                 public NamespaceEntry Parent {
 346                         get {
 347                                 return parent;
 348                         }
 349                 }
 350
 351                 public NamespaceEntry ImplicitParent {
 352                         get {
 353                                 if (parent == null)
 354                                         return null;
 355                                 if (implicit_parent == null) {
 356                                         implicit_parent = (parent.NS == ns.Parent)
 357                                                 ? parent
 358                                                 : new NamespaceEntry (parent, file, ns.Parent);
 359                                 }
 360                                 return implicit_parent;
 361                         }
 362                 }
 363
 364                 public void DefineName (string name, IAlias o)
 365                 {
 366                         ns.DefineName (name, o);
 367                 }
 368
 369                 /// <summary>
 370                 ///   Records a new namespace for resolving name references
 371                 /// </summary>
 372                 public void Using (Expression ns, Location loc)
 373                 {
 374                         string name = ns.ToString ();
 375                         if (DeclarationFound){
 376                                 Report.Error (1529, loc, "A using clause must precede all other namespace elements");
 377                                 return;
 378                         }
 379
 380                         if (name == FullName)
 381                                 return;
 382
 383                         if (using_clauses == null)
 384                                 using_clauses = new ArrayList ();
 385
 386                         foreach (UsingEntry old_entry in using_clauses) {
 387                                 if (old_entry.Name.ToString () == name) {
 388                                         if (RootContext.WarningLevel >= 3)
 389                                                 Report.Warning (105, loc, "The using directive for '{0}' appeared previously in this namespace", name);
 390                                         return;
 391                                 }
 392                         }
 393
 394
 395                         UsingEntry ue = new UsingEntry (Doppelganger, ns, loc);
 396                         using_clauses.Add (ue);
 397                 }
 398
 399                 public void UsingAlias (string name, Expression alias, Location loc)
 400                 {
 401                         if (DeclarationFound){
 402                                 Report.Error (1529, loc, "A using clause must precede all other namespace elements");
 403                                 return;
 404                         }
 405
 406                         if (aliases == null)
 407                                 aliases = new Hashtable ();
 408
 409                         if (aliases.Contains (name)){
 410                                 Report.Error (1537, loc, "The using alias `" + name +
 411                                               "' appeared previously in this namespace");
 412                                 return;
 413                         }
 414
 415                         aliases [name] = new AliasEntry (Doppelganger, name, alias, loc);
 416                 }
 417
 418                 public FullNamedExpression LookupAlias (string alias)
 419                 {
 420                         AliasEntry entry = null;
 421                         if (aliases != null)
 422                                 entry = (AliasEntry) aliases [alias];
 423
 424                         return entry == null ? null : entry.Resolve ();
 425                 }
 426
 427                 public FullNamedExpression LookupNamespaceOrType (DeclSpace ds, string name, Location loc)
 428                 {
 429                         FullNamedExpression resolved = null;
 430                         string rest = null;
 431
 432                         // If name is of the form `N.I', first lookup `N', then search a member `I' in it.
 433                         int pos = name.IndexOf ('.');
 434                         if (pos >= 0) {
 435                                 rest = name.Substring (pos + 1);
 436                                 name = name.Substring (0, pos);
 437                         }
 438
 439                         for (NamespaceEntry curr_ns = this; curr_ns != null; curr_ns = curr_ns.ImplicitParent) {
 440                                 if ((resolved = curr_ns.Lookup (ds, name, loc)) != null)
 441                                         break;
 442                         }
 443
 444                         if (resolved == null || rest == null)
 445                                 return resolved;
 446
 447                         Namespace ns = resolved as Namespace;
 448                         if (ns != null)
 449                                 return ns.Lookup (ds, rest, loc);
 450
 451                         Type nested = TypeManager.LookupType (resolved.FullName + "." + rest);
 452                         if ((nested == null) || ((ds != null) && !ds.CheckAccessLevel (nested)))
 453                                 return null;
 454
 455                         return new TypeExpression (nested, Location.Null);
 456                 }
 457
 458                 private FullNamedExpression Lookup (DeclSpace ds, string name, Location loc)
 459                 {
 460                         // Precondition: Only simple names (no dots) will be looked up with this function.
 461
 462                         //
 463                         // Check whether it's in the namespace.
 464                         //
 465                         FullNamedExpression o = NS.Lookup (ds, name, loc);
 466                         if (o != null)
 467                                 return o;
 468
 469                         if (IsImplicit)
 470                                 return null;
 471
 472                         //
 473                         // Check aliases.
 474                         //
 475                         o = LookupAlias (name);
 476                         if (o != null)
 477                                 return o;
 478
 479                         //
 480                         // Check using entries.
 481                         //
 482                         FullNamedExpression t = null, match = null;
 483                         foreach (Namespace using_ns in GetUsingTable ()) {
 484                                 match = using_ns.Lookup (ds, name, loc);
 485                                 if ((match != null) && (match is TypeExpr)) {
 486                                         if (t != null) {
 487                                                 DeclSpace.Error_AmbiguousTypeReference (loc, name, t.FullName, match.FullName);
 488                                                 return null;
 489                                         } else {
 490                                                 t = match;
 491                                         }
 492                                 }
 493                         }
 494
 495                         return t;
 496                 }
 497
 498                 // Our cached computation.
 499                 Namespace [] namespace_using_table;
 500                 public Namespace[] GetUsingTable ()
 501                 {
 502                         if (namespace_using_table != null)
 503                                 return namespace_using_table;
 504
 505                         if (using_clauses == null) {
 506                                 namespace_using_table = new Namespace [0];
 507                                 return namespace_using_table;
 508                         }
 509
 510                         ArrayList list = new ArrayList (using_clauses.Count);
 511
 512                         foreach (UsingEntry ue in using_clauses) {
 513                                 Namespace using_ns = ue.Resolve ();
 514                                 if (using_ns == null)
 515                                         continue;
 516
 517                                 list.Add (using_ns);
 518                         }
 519
 520                         namespace_using_table = new Namespace [list.Count];
 521                         list.CopyTo (namespace_using_table, 0);
 522                         return namespace_using_table;
 523                 }
 524
 525                 public void DefineNamespace (SymbolWriter symwriter)
 526                 {
 527                         if (symfile_id != 0)
 528                                 return;
 529                         if (parent != null)
 530                                 parent.DefineNamespace (symwriter);
 531
 532                         string[] using_list;
 533                         if (using_clauses != null) {
 534                                 using_list = new string [using_clauses.Count];
 535                                 for (int i = 0; i < using_clauses.Count; i++)
 536                                         using_list [i] = ((UsingEntry) using_clauses [i]).Name.ToString ();
 537                         } else {
 538                                 using_list = new string [0];
 539                         }
 540
 541                         int parent_id = parent != null ? parent.symfile_id : 0;
 542                         if (file.SourceFileEntry == null)
 543                                 return;
 544
 545                         symfile_id = symwriter.DefineNamespace (
 546                                 ns.Name, file.SourceFileEntry, using_list, parent_id);
 547                 }
 548
 549                 public int SymbolFileID {
 550                         get {
 551                                 return symfile_id;
 552                         }
 553                 }
 554
 555                 static void MsgtryRef (string s)
 556                 {
 557                         Console.WriteLine ("    Try using -r:" + s);
 558                 }
 559
 560                 static void MsgtryPkg (string s)
 561                 {
 562                         Console.WriteLine ("    Try using -pkg:" + s);
 563                 }
 564
 565                 protected void error246 (Location loc, string name)
 566                 {
 567                         Report.Error (246, loc, "The namespace `" + name +
 568                                       "' can not be found (missing assembly reference?)");
 569
 570                         switch (name) {
 571                         case "Gtk": case "GtkSharp":
 572                                 MsgtryPkg ("gtk-sharp");
 573                                 break;
 574
 575                         case "Gdk": case "GdkSharp":
 576                                 MsgtryPkg ("gdk-sharp");
 577                                 break;
 578
 579                         case "Glade": case "GladeSharp":
 580                                 MsgtryPkg ("glade-sharp");
 581                                 break;
 582
 583                         case "System.Drawing":
 584                         case "System.Web.Services":
 585                         case "System.Web":
 586                         case "System.Data":
 587                         case "System.Windows.Forms":
 588                                 MsgtryRef (name);
 589                                 break;
 590                         }
 591                 }
 592
 593                 /// <summary>
 594                 ///   Used to validate that all the using clauses are correct
 595                 ///   after we are finished parsing all the files.
 596                 /// </summary>
 597                 public void VerifyUsing ()
 598                 {
 599                         if (using_clauses != null){
 600                                 foreach (UsingEntry ue in using_clauses){
 601                                         if (ue.Resolve () != null)
 602                                                 continue;
 603
 604                                         if (ue.resolved == null)
 605                                                 error246 (ue.Location, ue.Name.ToString ());
 606                                         else
 607                                                 Report.Error (138, ue.Location, "The using keyword only lets you specify a namespace, " +
 608                                                               "`" + ue.Name + "' is a class not a namespace.");
 609
 610                                 }
 611                         }
 612
 613                         if (aliases != null){
 614                                 foreach (DictionaryEntry de in aliases){
 615                                         AliasEntry alias = (AliasEntry) de.Value;
 616
 617                                         if (alias.Resolve () != null)
 618                                                 continue;
 619
 620                                         error246 (alias.Location, alias.Alias.ToString ());
 621                                 }
 622                         }
 623                 }
 624
 625                 public override string ToString ()
 626                 {
 627                         if (NS == Namespace.Root)
 628                                 return "NamespaceEntry (<root>)";
 629                         else
 630                                 return String.Format ("NamespaceEntry ({0},{1},{2})", FullName, IsImplicit, ID);
 631                 }
 632         }
 633 }