mcs/mcs/eval.cs

   1 //
   2 // eval.cs: Evaluation and Hosting API for the C# compiler
   3 //
   4 // Authors:
   5 //   Miguel de Icaza (miguel@gnome.org)
   6 //   Marek Safar (marek.safar@gmail.com)
   7 //
   8 // Dual licensed under the terms of the MIT X11 or GNU GPL
   9 //
  10 // Copyright 2001, 2002, 2003 Ximian, Inc (http://www.ximian.com)
  11 // Copyright 2004-2011 Novell, Inc
  12 // Copyright 2011 Xamarin Inc
  13 //
  14
  15 using System;
  16 using System.Threading;
  17 using System.Collections.Generic;
  18 using System.Reflection;
  19 using System.Reflection.Emit;
  20 using System.IO;
  21 using System.Text;
  22 using System.Linq;
  23
  24 namespace Mono.CSharp
  25 {
  26
  27         /// <summary>
  28         /// Experimental!
  29         /// </summary>
  30         public delegate void ValueModificationHandler (string variableName, int row, int column, object value);
  31
  32         /// <summary>
  33         ///   Evaluator: provides an API to evaluate C# statements and
  34         ///   expressions dynamically.
  35         /// </summary>
  36         /// <remarks>
  37         ///   This class exposes static methods to evaluate expressions in the
  38         ///   current program.
  39         ///
  40         ///   To initialize the evaluator with a number of compiler
  41         ///   options call the Init(string[]args) method with a set of
  42         ///   command line options that the compiler recognizes.
  43         ///
  44         ///   To interrupt execution of a statement, you can invoke the
  45         ///   Evaluator.Interrupt method.
  46         /// </remarks>
  47         public class Evaluator {
  48
  49                 enum ParseMode {
  50                         // Parse silently, do not output any error messages
  51                         Silent,
  52
  53                         // Report errors during parse
  54                         ReportErrors,
  55
  56                         // Auto-complete, means that the tokenizer will start producing
  57                         // GETCOMPLETIONS tokens when it reaches a certain point.
  58                         GetCompletions
  59                 }
  60
  61                 static object evaluator_lock = new object ();
  62                 static volatile bool invoking;
  63
  64 #if !STATIC
  65                 static int count;
  66 #endif
  67                 static Thread invoke_thread;
  68
  69                 readonly Dictionary<string, Tuple<FieldSpec, FieldInfo>> fields;
  70
  71                 Type base_class;
  72                 bool inited;
  73                 int startup_files;
  74
  75                 readonly CompilerContext ctx;
  76                 readonly ModuleContainer module;
  77                 readonly ReflectionImporter importer;
  78                 readonly CompilationSourceFile source_file;
  79
  80                 int? listener_id;
  81
  82                 public Evaluator (CompilerContext ctx)
  83                 {
  84                         this.ctx = ctx;
  85
  86                         module = new ModuleContainer (ctx);
  87                         module.Evaluator = this;
  88
  89                         source_file = new CompilationSourceFile (module, null);
  90                         module.AddTypeContainer (source_file);
  91
  92                         startup_files = ctx.SourceFiles.Count;
  93
  94                         // FIXME: Importer needs this assembly for internalsvisibleto
  95                         module.SetDeclaringAssembly (new AssemblyDefinitionDynamic (module, "evaluator"));
  96                         importer = new ReflectionImporter (module, ctx.BuiltinTypes);
  97
  98                         InteractiveBaseClass = typeof (InteractiveBase);
  99                         fields = new Dictionary<string, Tuple<FieldSpec, FieldInfo>> ();
 100                 }
 101
 102                 void Init ()
 103                 {
 104                         var loader = new DynamicLoader (importer, ctx);
 105
 106                         CompilerCallableEntryPoint.Reset ();
 107                         RootContext.ToplevelTypes = module;
 108
 109                         //var startup_files = new List<string> ();
 110                         //foreach (CompilationUnit file in Location.SourceFiles)
 111                         //    startup_files.Add (file.Path);
 112
 113                         loader.LoadReferences (module);
 114                         ctx.BuiltinTypes.CheckDefinitions (module);
 115                         module.InitializePredefinedTypes ();
 116
 117                         inited = true;
 118                 }
 119
 120                 void ParseStartupFiles ()
 121                 {
 122                         Driver d = new Driver (ctx);
 123
 124                         Location.Initialize (ctx.SourceFiles);
 125
 126                         var parser_session = new ParserSession ();
 127                         for (int i = 0; i < startup_files; ++i) {
 128                                 var sf = ctx.SourceFiles [i];
 129                                 d.Parse (sf, module, parser_session, ctx.Report);
 130                         }
 131                 }
 132
 133                 void Reset ()
 134                 {
 135                         CompilerCallableEntryPoint.PartialReset ();
 136
 137                         Location.Reset ();
 138                         Location.Initialize (ctx.SourceFiles);
 139                 }
 140
 141                 /// <summary>
 142                 /// When set evaluator will automatically wait on Task of async methods. When not
 143                 /// set it's called responsibility to handle Task execution
 144                 /// </summary>
 145                 public bool WaitOnTask { get; set; }
 146
 147                 /// <summary>
 148                 ///   If true, turns type expressions into valid expressions
 149                 ///   and calls the describe method on it
 150                 /// </summary>
 151                 public bool DescribeTypeExpressions;
 152
 153                 /// <summary>
 154                 ///   Whether the evaluator will use terse syntax, and the semicolons at the end are optional
 155                 /// </summary>
 156                 public bool Terse = true;
 157
 158                 /// <summary>
 159                 ///   The base class for the classes that host the user generated code
 160                 /// </summary>
 161                 /// <remarks>
 162                 ///
 163                 ///   This is the base class that will host the code
 164                 ///   executed by the Evaluator.  By default
 165                 ///   this is the Mono.CSharp.InteractiveBase class
 166                 ///   which is useful for interactive use.
 167                 ///
 168                 ///   By changing this property you can control the
 169                 ///   base class and the static members that are
 170                 ///   available to your evaluated code.
 171                 /// </remarks>
 172                 public Type InteractiveBaseClass {
 173                         get {
 174                                 return base_class;
 175                         }
 176                         set {
 177                                 base_class = value;
 178
 179                                 if (value != null && typeof (InteractiveBase).IsAssignableFrom (value))
 180                                         InteractiveBase.Evaluator = this;
 181                         }
 182                 }
 183
 184                 /// <summary>
 185                 ///   Interrupts the evaluation of an expression executing in Evaluate.
 186                 /// </summary>
 187                 /// <remarks>
 188                 ///   Use this method to interrupt long-running invocations.
 189                 /// </remarks>
 190                 public void Interrupt ()
 191                 {
 192                         if (!inited || !invoking)
 193                                 return;
 194
 195                         if (invoke_thread != null) {
 196 #if MONO_FEATURE_THREAD_ABORT
 197                                 invoke_thread.Abort ();
 198 #else
 199                                 invoke_thread.Interrupt ();
 200 #endif
 201                         }
 202                 }
 203
 204                 /// <summary>
 205                 ///   Compiles the input string and returns a delegate that represents the compiled code.
 206                 /// </summary>
 207                 /// <remarks>
 208                 ///
 209                 ///   Compiles the input string as a C# expression or
 210                 ///   statement, unlike the Evaluate method, the
 211                 ///   resulting delegate can be invoked multiple times
 212                 ///   without incurring in the compilation overhead.
 213                 ///
 214                 ///   If the return value of this function is null,
 215                 ///   this indicates that the parsing was complete.
 216                 ///   If the return value is a string it indicates
 217                 ///   that the input string was partial and that the
 218                 ///   invoking code should provide more code before
 219                 ///   the code can be successfully compiled.
 220                 ///
 221                 ///   If you know that you will always get full expressions or
 222                 ///   statements and do not care about partial input, you can use
 223                 ///   the other Compile overload.
 224                 ///
 225                 ///   On success, in addition to returning null, the
 226                 ///   compiled parameter will be set to the delegate
 227                 ///   that can be invoked to execute the code.
 228                 ///
 229                 /// </remarks>
 230                 public string Compile (string input, out CompiledMethod compiled)
 231                 {
 232                         if (input == null || input.Length == 0){
 233                                 compiled = null;
 234                                 return null;
 235                         }
 236
 237                         lock (evaluator_lock){
 238                                 if (!inited) {
 239                                         Init ();
 240                                         ParseStartupFiles ();
 241                                 } else {
 242                                         ctx.Report.Printer.Reset ();
 243                                 }
 244
 245                                 bool partial_input;
 246                                 CSharpParser parser = ParseString (ParseMode.Silent, input, out partial_input);
 247
 248                                 // Terse mode, try to provide the trailing semicolon automatically.
 249                                 if (parser == null && Terse && partial_input){
 250                                         bool ignore;
 251
 252                                         // check if the source would compile with a block, if so, we should not
 253                                         // add the semicolon.
 254                                         var needs_block = ParseString (ParseMode.Silent, input + "{}", out ignore) != null;
 255                                         if (!needs_block)
 256                                                 parser = ParseString (ParseMode.Silent, input + ";", out ignore);
 257                                 }
 258                                 if (parser == null){
 259                                         compiled = null;
 260                                         if (partial_input)
 261                                                 return input;
 262
 263                                         ParseString (ParseMode.ReportErrors, input, out partial_input);
 264                                         return null;
 265                                 }
 266
 267                                 Class parser_result = parser.InteractiveResult;
 268                                 compiled = CompileBlock (parser_result, parser.undo, ctx.Report);
 269                                 return null;
 270                         }
 271                 }
 272
 273                 /// <summary>
 274                 ///   Compiles the input string and returns a delegate that represents the compiled code.
 275                 /// </summary>
 276                 /// <remarks>
 277                 ///
 278                 ///   Compiles the input string as a C# expression or
 279                 ///   statement, unlike the Evaluate method, the
 280                 ///   resulting delegate can be invoked multiple times
 281                 ///   without incurring in the compilation overhead.
 282                 ///
 283                 ///   This method can only deal with fully formed input
 284                 ///   strings and does not provide a completion mechanism.
 285                 ///   If you must deal with partial input (for example for
 286                 ///   interactive use) use the other overload.
 287                 ///
 288                 ///   On success, a delegate is returned that can be used
 289                 ///   to invoke the method.
 290                 ///
 291                 /// </remarks>
 292                 public CompiledMethod Compile (string input)
 293                 {
 294                         CompiledMethod compiled;
 295
 296                         // Ignore partial inputs
 297                         if (Compile (input, out compiled) != null){
 298                                 // Error, the input was partial.
 299                                 return null;
 300                         }
 301
 302                         // Either null (on error) or the compiled method.
 303                         return compiled;
 304                 }
 305
 306                 static MethodInfo listener_proxy_value;
 307                 internal void EmitValueChangedCallback (EmitContext ec, string name, TypeSpec type, Location loc)
 308                 {
 309                         if (listener_id == null)
 310                                 listener_id = ListenerProxy.Register (ModificationListener);
 311
 312                         if (listener_proxy_value == null)
 313                                 listener_proxy_value = typeof (ListenerProxy).GetMethod ("ValueChanged");
 314
 315 #if STATIC
 316                         throw new NotSupportedException ();
 317 #else
 318                         // object value, int row, int col, string name, int listenerId
 319                         if (type.IsStructOrEnum)
 320                                 ec.Emit (OpCodes.Box, type);
 321
 322                         ec.EmitInt (loc.Row);
 323                         ec.EmitInt (loc.Column);
 324                         ec.Emit (OpCodes.Ldstr, name);
 325                         ec.EmitInt (listener_id.Value);
 326                         ec.Emit (OpCodes.Call, listener_proxy_value);
 327 #endif
 328                 }
 329
 330                 /// <summary>
 331                 ///   Evaluates and expression or statement and returns any result values.
 332                 /// </summary>
 333                 /// <remarks>
 334                 ///   Evaluates the input string as a C# expression or
 335                 ///   statement.  If the input string is an expression
 336                 ///   the result will be stored in the result variable
 337                 ///   and the result_set variable will be set to true.
 338                 ///
 339                 ///   It is necessary to use the result/result_set
 340                 ///   pair to identify when a result was set (for
 341                 ///   example, execution of user-provided input can be
 342                 ///   an expression, a statement or others, and
 343                 ///   result_set would only be set if the input was an
 344                 ///   expression.
 345                 ///
 346                 ///   If the return value of this function is null,
 347                 ///   this indicates that the parsing was complete.
 348                 ///   If the return value is a string, it indicates
 349                 ///   that the input is partial and that the user
 350                 ///   should provide an updated string.
 351                 /// </remarks>
 352                 public string Evaluate (string input, out object result, out bool result_set)
 353                 {
 354                         CompiledMethod compiled;
 355
 356                         result_set = false;
 357                         result = null;
 358
 359                         input = Compile (input, out compiled);
 360                         if (input != null)
 361                                 return input;
 362
 363                         if (compiled == null)
 364                                 return null;
 365
 366                         //
 367                         // The code execution does not need to keep the compiler lock
 368                         //
 369                         object retval = typeof (QuitValue);
 370
 371                         try {
 372                                 invoke_thread = System.Threading.Thread.CurrentThread;
 373                                 invoking = true;
 374                                 compiled (ref retval);
 375 #if MONO_FEATURE_THREAD_ABORT
 376                         } catch (ThreadAbortException e){
 377                                 Thread.ResetAbort ();
 378                                 Console.WriteLine ("Interrupted!\n{0}", e);
 379 #else
 380                         } catch (ThreadInterruptedException e) {
 381                                 Console.WriteLine ("Interrupted!\n{0}", e);
 382 #endif
 383                         } finally {
 384                                 invoking = false;
 385
 386                                 if (listener_id != null) {
 387                                         ListenerProxy.Unregister (listener_id.Value);
 388                                         listener_id = null;
 389                                 }
 390                         }
 391
 392                         //
 393                         // We use a reference to a compiler type, in this case
 394                         // Driver as a flag to indicate that this was a statement
 395                         //
 396                         if (!ReferenceEquals (retval, typeof (QuitValue))) {
 397                                 result_set = true;
 398                                 result = retval;
 399                         }
 400
 401                         return null;
 402                 }
 403
 404                 public string [] GetCompletions (string input, out string prefix)
 405                 {
 406                         prefix = "";
 407                         if (input == null || input.Length == 0)
 408                                 return null;
 409
 410                         lock (evaluator_lock){
 411                                 if (!inited)
 412                                         Init ();
 413
 414                                 bool partial_input;
 415                                 CSharpParser parser = ParseString (ParseMode.GetCompletions, input, out partial_input);
 416                                 if (parser == null){
 417                                         return null;
 418                                 }
 419
 420                                 Class host = parser.InteractiveResult;
 421
 422                                 var base_class_imported = importer.ImportType (base_class);
 423                                 var baseclass_list = new List<FullNamedExpression> (1) {
 424                                         new TypeExpression (base_class_imported, host.Location)
 425                                 };
 426                                 host.SetBaseTypes (baseclass_list);
 427
 428                                 var access = AssemblyBuilderAccess.RunAndCollect;
 429                                 var a = new AssemblyDefinitionDynamic (module, "completions");
 430                                 a.Create (AppDomain.CurrentDomain, access);
 431                                 module.SetDeclaringAssembly (a);
 432
 433                                 // Need to setup MemberCache
 434                                 host.CreateContainer ();
 435                                 // Need to setup base type
 436                                 host.DefineContainer ();
 437
 438                                 var method = host.Members[0] as Method;
 439                                 BlockContext bc = new BlockContext (method, method.Block, ctx.BuiltinTypes.Void);
 440
 441                                 try {
 442                                         method.Block.Resolve (bc, method);
 443                                 } catch (CompletionResult cr) {
 444                                         prefix = cr.BaseText;
 445                                         return cr.Result;
 446                                 }
 447                         }
 448                         return null;
 449                 }
 450
 451                 /// <summary>
 452                 ///   Executes the given expression or statement.
 453                 /// </summary>
 454                 /// <remarks>
 455                 ///    Executes the provided statement, returns true
 456                 ///    on success, false on parsing errors.  Exceptions
 457                 ///    might be thrown by the called code.
 458                 /// </remarks>
 459                 public bool Run (string statement)
 460                 {
 461                         object result;
 462                         bool result_set;
 463
 464                         return Evaluate (statement, out result, out result_set) == null;
 465                 }
 466
 467                 /// <summary>
 468                 ///   Evaluates and expression or statement and returns the result.
 469                 /// </summary>
 470                 /// <remarks>
 471                 ///   Evaluates the input string as a C# expression or
 472                 ///   statement and returns the value.
 473                 ///
 474                 ///   This method will throw an exception if there is a syntax error,
 475                 ///   of if the provided input is not an expression but a statement.
 476                 /// </remarks>
 477                 public object Evaluate (string input)
 478                 {
 479                         object result;
 480                         bool result_set;
 481
 482                         string r = Evaluate (input, out result, out result_set);
 483
 484                         if (r != null)
 485                                 throw new ArgumentException ("Syntax error on input: partial input");
 486
 487                         if (result_set == false)
 488                                 throw new ArgumentException ("The expression failed to resolve");
 489
 490                         return result;
 491                 }
 492
 493                 /// <summary>
 494                 /// Experimental!
 495                 /// </summary>
 496                 public ValueModificationHandler ModificationListener { get; set; }
 497
 498                 enum InputKind {
 499                         EOF,
 500                         StatementOrExpression,
 501                         CompilationUnit,
 502                         Error
 503                 }
 504
 505                 //
 506                 // Deambiguates the input string to determine if we
 507                 // want to process a statement or if we want to
 508                 // process a compilation unit.
 509                 //
 510                 // This is done using a top-down predictive parser,
 511                 // since the yacc/jay parser can not deambiguage this
 512                 // without more than one lookahead token.   There are very
 513                 // few ambiguities.
 514                 //
 515                 InputKind ToplevelOrStatement (SeekableStreamReader seekable)
 516                 {
 517                         Tokenizer tokenizer = new Tokenizer (seekable, source_file, new ParserSession (), ctx.Report);
 518
 519                         // Prefer contextual block keywords over identifiers
 520                         tokenizer.parsing_block++;
 521
 522                         int t = tokenizer.token ();
 523                         switch (t){
 524                         case Token.EOF:
 525                                 return InputKind.EOF;
 526
 527                         // These are toplevels
 528                         case Token.EXTERN:
 529                         case Token.OPEN_BRACKET:
 530                         case Token.OPEN_BRACKET_EXPR:
 531                         case Token.ABSTRACT:
 532                         case Token.CLASS:
 533                         case Token.ENUM:
 534                         case Token.INTERFACE:
 535                         case Token.INTERNAL:
 536                         case Token.NAMESPACE:
 537                         case Token.PRIVATE:
 538                         case Token.PROTECTED:
 539                         case Token.PUBLIC:
 540                         case Token.SEALED:
 541                         case Token.STATIC:
 542                         case Token.STRUCT:
 543                                 return InputKind.CompilationUnit;
 544
 545                         // Definitely expression
 546                         case Token.FIXED:
 547                         case Token.BOOL:
 548                         case Token.BYTE:
 549                         case Token.CHAR:
 550                         case Token.DECIMAL:
 551                         case Token.DOUBLE:
 552                         case Token.FLOAT:
 553                         case Token.INT:
 554                         case Token.LONG:
 555                         case Token.NEW:
 556                         case Token.OBJECT:
 557                         case Token.SBYTE:
 558                         case Token.SHORT:
 559                         case Token.STRING:
 560                         case Token.UINT:
 561                         case Token.ULONG:
 562                                 return InputKind.StatementOrExpression;
 563
 564                         // These need deambiguation help
 565                         case Token.USING:
 566                                 t = tokenizer.token ();
 567                                 if (t == Token.EOF)
 568                                         return InputKind.EOF;
 569
 570                                 if (t == Token.IDENTIFIER || t == Token.STATIC)
 571                                         return InputKind.CompilationUnit;
 572                                 return InputKind.StatementOrExpression;
 573
 574
 575                         // Distinguish between:
 576                         //    delegate opt_anonymous_method_signature block
 577                         //    delegate type
 578                         case Token.DELEGATE:
 579                                 t = tokenizer.token ();
 580                                 if (t == Token.EOF)
 581                                         return InputKind.EOF;
 582                                 if (t == Token.OPEN_PARENS || t == Token.OPEN_BRACE)
 583                                         return InputKind.StatementOrExpression;
 584                                 return InputKind.CompilationUnit;
 585
 586                         // Distinguih between:
 587                         //    unsafe block
 588                         //    unsafe as modifier of a type declaration
 589                         case Token.UNSAFE:
 590                                 t = tokenizer.token ();
 591                                 if (t == Token.EOF)
 592                                         return InputKind.EOF;
 593                                 if (t == Token.OPEN_PARENS)
 594                                         return InputKind.StatementOrExpression;
 595                                 return InputKind.CompilationUnit;
 596
 597                         // These are errors: we list explicitly what we had
 598                         // from the grammar, ERROR and then everything else
 599
 600                         case Token.READONLY:
 601                         case Token.OVERRIDE:
 602                         case Token.ERROR:
 603                                 return InputKind.Error;
 604
 605                         // This catches everything else allowed by
 606                         // expressions.  We could add one-by-one use cases
 607                         // if needed.
 608                         default:
 609                                 return InputKind.StatementOrExpression;
 610                         }
 611                 }
 612
 613                 //
 614                 // Parses the string @input and returns a CSharpParser if succeeful.
 615                 //
 616                 // if @silent is set to true then no errors are
 617                 // reported to the user.  This is used to do various calls to the
 618                 // parser and check if the expression is parsable.
 619                 //
 620                 // @partial_input: if @silent is true, then it returns whether the
 621                 // parsed expression was partial, and more data is needed
 622                 //
 623                 CSharpParser ParseString (ParseMode mode, string input, out bool partial_input)
 624                 {
 625                         partial_input = false;
 626                         Reset ();
 627
 628                         var enc = ctx.Settings.Encoding;
 629                         var s = new MemoryStream (enc.GetBytes (input));
 630                         SeekableStreamReader seekable = new SeekableStreamReader (s, enc);
 631
 632                         InputKind kind = ToplevelOrStatement (seekable);
 633                         if (kind == InputKind.Error){
 634                                 if (mode == ParseMode.ReportErrors)
 635                                         ctx.Report.Error (-25, "Detection Parsing Error");
 636                                 partial_input = false;
 637                                 return null;
 638                         }
 639
 640                         if (kind == InputKind.EOF){
 641                                 if (mode == ParseMode.ReportErrors)
 642                                         Console.Error.WriteLine ("Internal error: EOF condition should have been detected in a previous call with silent=true");
 643                                 partial_input = true;
 644                                 return null;
 645
 646                         }
 647                         seekable.Position = 0;
 648
 649                         source_file.DeclarationFound = false;
 650                         CSharpParser parser = new CSharpParser (seekable, source_file, new ParserSession ());
 651
 652                         if (kind == InputKind.StatementOrExpression){
 653                                 parser.Lexer.putback_char = Tokenizer.EvalStatementParserCharacter;
 654                                 parser.Lexer.parsing_block++;
 655                                 ctx.Settings.StatementMode = true;
 656                         } else {
 657                                 parser.Lexer.putback_char = Tokenizer.EvalCompilationUnitParserCharacter;
 658                                 ctx.Settings.StatementMode = false;
 659                         }
 660
 661                         if (mode == ParseMode.GetCompletions)
 662                                 parser.Lexer.CompleteOnEOF = true;
 663
 664                         ReportPrinter old_printer = null;
 665                         if ((mode == ParseMode.Silent || mode == ParseMode.GetCompletions))
 666                                 old_printer = ctx.Report.SetPrinter (new StreamReportPrinter (TextWriter.Null));
 667
 668                         try {
 669                                 parser.parse ();
 670                         } finally {
 671                                 if (ctx.Report.Errors != 0){
 672                                         if (mode != ParseMode.ReportErrors  && parser.UnexpectedEOF)
 673                                                 partial_input = true;
 674
 675                                         if (parser.undo != null)
 676                                                 parser.undo.ExecuteUndo ();
 677
 678                                         parser = null;
 679                                 }
 680
 681                                 if (old_printer != null)
 682                                         ctx.Report.SetPrinter (old_printer);
 683                         }
 684                         return parser;
 685                 }
 686
 687                 CompiledMethod CompileBlock (Class host, Undo undo, Report Report)
 688                 {
 689 #if STATIC
 690                         throw new NotSupportedException ();
 691 #else
 692                         string current_debug_name = "eval-" + count + ".dll";
 693                         ++count;
 694
 695                         AssemblyDefinitionDynamic assembly;
 696                         AssemblyBuilderAccess access;
 697
 698                         if (Environment.GetEnvironmentVariable ("SAVE") != null) {
 699                                 access = AssemblyBuilderAccess.RunAndSave;
 700                                 assembly = new AssemblyDefinitionDynamic (module, current_debug_name, current_debug_name);
 701                                 assembly.Importer = importer;
 702                         } else {
 703                                 access = AssemblyBuilderAccess.RunAndCollect;
 704                                 assembly = new AssemblyDefinitionDynamic (module, current_debug_name);
 705                         }
 706
 707                         assembly.Create (AppDomain.CurrentDomain, access);
 708
 709                         Method expression_method;
 710                         if (host != null) {
 711                                 var base_class_imported = importer.ImportType (base_class);
 712                                 var baseclass_list = new List<FullNamedExpression> (1) {
 713                                         new TypeExpression (base_class_imported, host.Location)
 714                                 };
 715
 716                                 host.SetBaseTypes (baseclass_list);
 717
 718                                 expression_method = (Method) host.Members[0];
 719
 720                                 if ((expression_method.ModFlags & Modifiers.ASYNC) != 0) {
 721                                         //
 722                                         // Host method is async. When WaitOnTask is set we wrap it with wait
 723                                         //
 724                                         // void AsyncWait (ref object $retval) {
 725                                         //      $retval = Host();
 726                                         //      ((Task)$retval).Wait();  // When WaitOnTask is set
 727                                         // }
 728                                         //
 729                                         var p = new ParametersCompiled (
 730                                                 new Parameter (new TypeExpression (module.Compiler.BuiltinTypes.Object, Location.Null), "$retval", Parameter.Modifier.REF, null, Location.Null)
 731                                         );
 732
 733                                         var method = new Method(host, new TypeExpression(module.Compiler.BuiltinTypes.Void, Location.Null),
 734                                                 Modifiers.PUBLIC | Modifiers.STATIC, new MemberName("AsyncWait"), p, null);
 735
 736                                         method.Block = new ToplevelBlock(method.Compiler, p, Location.Null);
 737                                         method.Block.AddStatement(new StatementExpression (new SimpleAssign(
 738                                                 new SimpleName(p [0].Name, Location.Null),
 739                                                 new Invocation(new SimpleName(expression_method.MemberName.Name, Location.Null), new Arguments(0)),
 740                                                 Location.Null), Location.Null));
 741
 742                                         if (WaitOnTask) {
 743                                                 var task = new Cast (expression_method.TypeExpression, new SimpleName (p [0].Name, Location.Null), Location.Null);
 744
 745                                                 method.Block.AddStatement (new StatementExpression (new Invocation (
 746                                                                 new MemberAccess (task, "Wait", Location.Null),
 747                                                         new Arguments (0)), Location.Null));
 748                                         }
 749
 750                                         host.AddMember(method);
 751
 752                                         expression_method = method;
 753                                 }
 754
 755                                 host.CreateContainer();
 756                                 host.DefineContainer();
 757                                 host.Define();
 758
 759                         } else {
 760                                 expression_method = null;
 761                         }
 762
 763                         module.CreateContainer ();
 764
 765                         // Disable module and source file re-definition checks
 766                         module.EnableRedefinition ();
 767                         source_file.EnableRedefinition ();
 768
 769                         module.Define ();
 770
 771                         if (Report.Errors != 0){
 772                                 if (undo != null)
 773                                         undo.ExecuteUndo ();
 774
 775                                 return null;
 776                         }
 777
 778                         if (host != null){
 779                                 host.PrepareEmit ();
 780                                 host.EmitContainer ();
 781                         }
 782
 783                         module.EmitContainer ();
 784
 785                         if (Report.Errors != 0){
 786                                 if (undo != null)
 787                                         undo.ExecuteUndo ();
 788                                 return null;
 789                         }
 790
 791                         module.CloseContainer ();
 792                         if (host != null)
 793                                 host.CloseContainer ();
 794
 795                         if (access == AssemblyBuilderAccess.RunAndSave)
 796                                 assembly.Save ();
 797
 798                         if (host == null)
 799                                 return null;
 800
 801                         //
 802                         // Unlike Mono, .NET requires that the MethodInfo is fetched, it cant
 803                         // work from MethodBuilders.   Retarded, I know.
 804                         //
 805                         var tt = assembly.Builder.GetType (host.TypeBuilder.Name);
 806                         var mi = tt.GetMethod (expression_method.MemberName.Name);
 807
 808                         //
 809                         // We need to then go from FieldBuilder to FieldInfo
 810                         // or reflection gets confused (it basically gets confused, and variables override each
 811                         // other).
 812                         //
 813                         foreach (var member in host.Members) {
 814                                 var field = member as Field;
 815                                 if (field == null)
 816                                         continue;
 817
 818                                 var fi = tt.GetField (field.Name);
 819
 820                                 Tuple<FieldSpec, FieldInfo> old;
 821
 822                                 // If a previous value was set, nullify it, so that we do
 823                                 // not leak memory
 824                                 if (fields.TryGetValue (field.Name, out old)) {
 825                                         if (old.Item1.MemberType.IsStruct) {
 826                                                 //
 827                                                 // TODO: Clear fields for structs
 828                                                 //
 829                                         } else {
 830                                                 try {
 831                                                         old.Item2.SetValue (null, null);
 832                                                 } catch {
 833                                                 }
 834                                         }
 835                                 }
 836
 837                                 fields[field.Name] = Tuple.Create (field.Spec, fi);
 838                         }
 839
 840                         return (CompiledMethod) System.Delegate.CreateDelegate (typeof (CompiledMethod), mi);
 841 #endif
 842                 }
 843
 844                 /// <summary>
 845                 ///   A sentinel value used to indicate that no value was
 846                 ///   was set by the compiled function.   This is used to
 847                 ///   differentiate between a function not returning a
 848                 ///   value and null.
 849                 /// </summary>
 850                 internal static class QuitValue { }
 851
 852                 internal Tuple<FieldSpec, FieldInfo> LookupField (string name)
 853                 {
 854                         Tuple<FieldSpec, FieldInfo> fi;
 855                         fields.TryGetValue (name, out fi);
 856                         return fi;
 857                 }
 858
 859                 static string Quote (string s)
 860                 {
 861                         if (s.IndexOf ('"') != -1)
 862                                 s = s.Replace ("\"", "\\\"");
 863
 864                         return "\"" + s + "\"";
 865                 }
 866
 867                 public string GetUsing ()
 868                 {
 869                         if (source_file == null || source_file.Usings == null)
 870                                 return string.Empty;
 871
 872                         StringBuilder sb = new StringBuilder ();
 873                         // TODO:
 874                         //foreach (object x in ns.using_alias_list)
 875                         //    sb.AppendFormat ("using {0};\n", x);
 876
 877                         foreach (var ue in source_file.Usings) {
 878                                 if (ue.Alias != null || ue.ResolvedExpression == null)
 879                                         continue;
 880
 881                                 sb.AppendFormat("using {0};", ue.ToString ());
 882                                 sb.Append (Environment.NewLine);
 883                         }
 884
 885                         return sb.ToString ();
 886                 }
 887
 888                 internal List<string> GetUsingList ()
 889                 {
 890                         var res = new List<string> ();
 891
 892                         if (source_file == null || source_file.Usings == null)
 893                                 return res;
 894
 895                         foreach (var ue in source_file.Usings)
 896                         {
 897                                 if (ue.Alias != null || ue.ResolvedExpression == null)
 898                                         continue;
 899
 900                                 res.Add (ue.NamespaceExpression.Name);
 901                         }
 902
 903                         return res;
 904                 }
 905
 906                 internal string [] GetVarNames ()
 907                 {
 908                         lock (evaluator_lock){
 909                                 return new List<string> (fields.Keys).ToArray ();
 910                         }
 911                 }
 912
 913                 public string GetVars ()
 914                 {
 915                         lock (evaluator_lock){
 916                                 StringBuilder sb = new StringBuilder ();
 917
 918                                 foreach (var de in fields){
 919                                         var fi = LookupField (de.Key);
 920                                         object value;
 921                                         try {
 922                                                 value = fi.Item2.GetValue (null);
 923                                                 if (value is string)
 924                                                         value = Quote ((string)value);
 925                                         } catch {
 926                                                 value = "<error reading value>";
 927                                         }
 928
 929                                         sb.AppendFormat ("{0} {1} = {2}", fi.Item1.MemberType.GetSignatureForError (), de.Key, value);
 930                                         sb.AppendLine ();
 931                                 }
 932
 933                                 return sb.ToString ();
 934                         }
 935                 }
 936
 937                 /// <summary>
 938                 ///    Loads the given assembly and exposes the API to the user.
 939                 /// </summary>
 940                 public void LoadAssembly (string file)
 941                 {
 942                         var loader = new DynamicLoader (importer, ctx);
 943                         var assembly = loader.LoadAssemblyFile (file, false);
 944                         if (assembly == null)
 945                                 return;
 946
 947                         lock (evaluator_lock){
 948                                 importer.ImportAssembly (assembly, module.GlobalRootNamespace);
 949                         }
 950                 }
 951
 952                 /// <summary>
 953                 ///    Exposes the API of the given assembly to the Evaluator
 954                 /// </summary>
 955                 public void ReferenceAssembly (Assembly a)
 956                 {
 957                         lock (evaluator_lock){
 958                                 importer.ImportAssembly (a, module.GlobalRootNamespace);
 959                         }
 960                 }
 961
 962                 public void ImportTypes (bool importExtensionTypes, params Type[] types) {
 963 #if !STATIC
 964                         importer.ImportTypes (types, module.GlobalRootNamespace, importExtensionTypes);
 965 #endif
 966                 }
 967         }
 968
 969
 970         /// <summary>
 971         ///   A delegate that can be used to invoke the
 972         ///   compiled expression or statement.
 973         /// </summary>
 974         /// <remarks>
 975         ///   Since the Compile methods will compile
 976         ///   statements and expressions into the same
 977         ///   delegate, you can tell if a value was returned
 978         ///   by checking whether the returned value is of type
 979         ///   NoValueSet.
 980         /// </remarks>
 981
 982         public delegate void CompiledMethod (ref object retvalue);
 983
 984         /// <summary>
 985         ///   The default base class for every interaction line
 986         /// </summary>
 987         /// <remarks>
 988         ///   The expressions and statements behave as if they were
 989         ///   a static method of this class.   The InteractiveBase class
 990         ///   contains a number of useful methods, but can be overwritten
 991         ///   by setting the InteractiveBaseType property in the Evaluator
 992         /// </remarks>
 993         public class InteractiveBase {
 994                 /// <summary>
 995                 ///   Determines where the standard output of methods in this class will go.
 996                 /// </summary>
 997                 public static TextWriter Output = Console.Out;
 998
 999                 /// <summary>
1000                 ///   Determines where the standard error of methods in this class will go.
1001                 /// </summary>
1002                 public static TextWriter Error = Console.Error;
1003
1004                 /// <summary>
1005                 ///   The primary prompt used for interactive use.
1006                 /// </summary>
1007                 public static string Prompt             = "csharp> ";
1008
1009                 /// <summary>
1010                 ///   The secondary prompt used for interactive use (used when
1011                 ///   an expression is incomplete).
1012                 /// </summary>
1013                 public static string ContinuationPrompt = "      > ";
1014
1015                 /// <summary>
1016                 ///   Used to signal that the user has invoked the  `quit' statement.
1017                 /// </summary>
1018                 public static bool QuitRequested;
1019
1020                 public static Evaluator Evaluator;
1021
1022                 /// <summary>
1023                 ///   Shows all the variables defined so far.
1024                 /// </summary>
1025                 static public void ShowVars ()
1026                 {
1027                         Output.Write (Evaluator.GetVars ());
1028                         Output.Flush ();
1029                 }
1030
1031                 /// <summary>
1032                 ///   Displays the using statements in effect at this point.
1033                 /// </summary>
1034                 static public void ShowUsing ()
1035                 {
1036                         Output.Write (Evaluator.GetUsing ());
1037                         Output.Flush ();
1038                 }
1039
1040                 /// <summary>
1041                 ///   Times the execution of the given delegate
1042                 /// </summary>
1043                 static public TimeSpan Time (Action a)
1044                 {
1045                         DateTime start = DateTime.Now;
1046                         a ();
1047                         return DateTime.Now - start;
1048                 }
1049
1050                 /// <summary>
1051                 ///   Loads the assemblies from a package
1052                 /// </summary>
1053                 /// <remarks>
1054                 ///   Loads the assemblies from a package.   This is equivalent
1055                 ///   to passing the -pkg: command line flag to the C# compiler
1056                 ///   on the command line.
1057                 /// </remarks>
1058                 static public void LoadPackage (string pkg)
1059                 {
1060                         if (pkg == null){
1061                                 Error.WriteLine ("Invalid package specified");
1062                                 return;
1063                         }
1064
1065                         string pkgout = Driver.GetPackageFlags (pkg, null);
1066
1067                         string [] xargs = pkgout.Trim (new Char [] {' ', '\n', '\r', '\t'}).
1068                                 Split (new Char [] { ' ', '\t'});
1069
1070                         foreach (string s in xargs){
1071                                 if (s.StartsWith ("-r:") || s.StartsWith ("/r:") || s.StartsWith ("/reference:")){
1072                                         string lib = s.Substring (s.IndexOf (':')+1);
1073
1074                                         Evaluator.LoadAssembly (lib);
1075                                         continue;
1076                                 }
1077                         }
1078                 }
1079
1080                 /// <summary>
1081                 ///   Loads the assembly
1082                 /// </summary>
1083                 /// <remarks>
1084                 ///   Loads the specified assembly and makes its types
1085                 ///   available to the evaluator.  This is equivalent
1086                 ///   to passing the -pkg: command line flag to the C#
1087                 ///   compiler on the command line.
1088                 /// </remarks>
1089                 static public void LoadAssembly (string assembly)
1090                 {
1091                         Evaluator.LoadAssembly (assembly);
1092                 }
1093
1094                 static public void print (object obj)
1095                 {
1096                         Output.WriteLine (obj);
1097                 }
1098
1099                 static public void print (string fmt, params object [] args)
1100                 {
1101                         Output.WriteLine (fmt, args);
1102                 }
1103
1104                 /// <summary>
1105                 ///   Returns a list of available static methods.
1106                 /// </summary>
1107                 static public string help {
1108                         get {
1109                                 return "Static methods:\n" +
1110                                         "  Describe (object);       - Describes the object's type\n" +
1111                                         "  LoadPackage (package);   - Loads the given Package (like -pkg:FILE)\n" +
1112                                         "  LoadAssembly (assembly); - Loads the given assembly (like -r:ASSEMBLY)\n" +
1113                                         "  ShowVars ();             - Shows defined local variables.\n" +
1114                                         "  ShowUsing ();            - Show active using declarations.\n" +
1115                                         "  Prompt                   - The prompt used by the C# shell\n" +
1116                                         "  ContinuationPrompt       - The prompt for partial input\n" +
1117                                         "  Time (() => { });        - Times the specified code\n" +
1118                                         "  print (obj);             - Shorthand for Console.WriteLine\n" +
1119                                         "  quit;                    - You'll never believe it - this quits the repl!\n" +
1120                                         "  help;                    - This help text\n";
1121                         }
1122                 }
1123
1124                 /// <summary>
1125                 ///   Indicates to the read-eval-print-loop that the interaction should be finished.
1126                 /// </summary>
1127                 static public object quit {
1128                         get {
1129                                 QuitRequested = true;
1130
1131                                 // To avoid print null at the exit
1132                                 return typeof (Evaluator.QuitValue);
1133                         }
1134                 }
1135
1136                 /// <summary>
1137                 ///   Same as quit - useful in script scenerios
1138                 /// </summary>
1139                 static public void Quit () {
1140                         QuitRequested = true;
1141                 }
1142
1143 #if !MOBILE
1144                 /// <summary>
1145                 ///   Describes an object or a type.
1146                 /// </summary>
1147                 /// <remarks>
1148                 ///   This method will show a textual representation
1149                 ///   of the object's type.  If the object is a
1150                 ///   System.Type it renders the type directly,
1151                 ///   otherwise it renders the type returned by
1152                 ///   invoking GetType on the object.
1153                 /// </remarks>
1154                 static public string Describe (object x)
1155                 {
1156                         if (x == null)
1157                                 return "<null>";
1158
1159                         var type = x as Type ?? x.GetType ();
1160
1161                         StringWriter sw = new StringWriter ();
1162                         new Outline (type, sw, true, false, false).OutlineType ();
1163                         return sw.ToString ();
1164                 }
1165 #endif
1166         }
1167
1168         class InteractiveMethod : Method
1169         {
1170                 public InteractiveMethod(TypeDefinition parent, FullNamedExpression returnType, Modifiers mod, ParametersCompiled parameters)
1171                         : base(parent, returnType, mod, new MemberName("Host"), parameters, null)
1172                 {
1173                 }
1174
1175                 public void ChangeToAsync ()
1176                 {
1177                         ModFlags |= Modifiers.ASYNC;
1178                         ModFlags &= ~Modifiers.UNSAFE;
1179                         type_expr = new TypeExpression(Module.PredefinedTypes.Task.TypeSpec, Location);
1180                         parameters = ParametersCompiled.EmptyReadOnlyParameters;
1181                 }
1182
1183                 public override string GetSignatureForError()
1184                 {
1185                         return "InteractiveHost";
1186                 }
1187         }
1188
1189         class HoistedEvaluatorVariable : HoistedVariable
1190         {
1191                 public HoistedEvaluatorVariable (Field field)
1192                         : base (null, field)
1193                 {
1194                 }
1195
1196                 protected override FieldExpr GetFieldExpression (EmitContext ec)
1197                 {
1198                         return new FieldExpr (field, field.Location);
1199                 }
1200         }
1201
1202         /// <summary>
1203         ///    A class used to assign values if the source expression is not void
1204         ///
1205         ///    Used by the interactive shell to allow it to call this code to set
1206         ///    the return value for an invocation.
1207         /// </summary>
1208         class OptionalAssign : SimpleAssign {
1209                 public OptionalAssign (Expression s, Location loc)
1210                         : base (null, s, loc)
1211                 {
1212                 }
1213
1214                 public override Location StartLocation {
1215                         get {
1216                                 return Location.Null;
1217                         }
1218                 }
1219
1220                 protected override Expression DoResolve (ResolveContext ec)
1221                 {
1222                         Expression clone = source.Clone (new CloneContext ());
1223
1224                         clone = clone.Resolve (ec);
1225                         if (clone == null)
1226                                 return null;
1227
1228                         //
1229                         // A useful feature for the REPL: if we can resolve the expression
1230                         // as a type, Describe the type;
1231                         //
1232                         if (ec.Module.Evaluator.DescribeTypeExpressions && !(ec.CurrentAnonymousMethod is AsyncInitializer)) {
1233                                 var old_printer = ec.Report.SetPrinter (new SessionReportPrinter ());
1234                                 Expression tclone;
1235                                 try {
1236                                         // Note: clone context cannot be shared otherwise block mapping would leak
1237                                         tclone = source.Clone (new CloneContext ());
1238                                         tclone = tclone.Resolve (ec, ResolveFlags.Type);
1239                                         if (ec.Report.Errors > 0)
1240                                                 tclone = null;
1241                                 } finally {
1242                                         ec.Report.SetPrinter (old_printer);
1243                                 }
1244
1245                                 if (tclone is TypeExpr) {
1246                                         Arguments args = new Arguments (1);
1247                                         args.Add (new Argument (new TypeOf ((TypeExpr) clone, Location)));
1248                                         return new Invocation (new SimpleName ("Describe", Location), args).Resolve (ec);
1249                                 }
1250                         }
1251
1252                         // This means its really a statement.
1253                         if (clone.Type.Kind == MemberKind.Void || clone is DynamicInvocation || clone is Assign) {
1254                                 return clone;
1255                         }
1256
1257                         source = clone;
1258
1259                         var host = (Method) ec.MemberContext.CurrentMemberDefinition;
1260
1261                         if (host.ParameterInfo.IsEmpty) {
1262                                 eclass = ExprClass.Value;
1263                                 type = InternalType.FakeInternalType;
1264                                 return this;
1265                         }
1266
1267                         target = new SimpleName (host.ParameterInfo[0].Name, Location);
1268
1269                         return base.DoResolve (ec);
1270                 }
1271
1272                 public override void EmitStatement(EmitContext ec)
1273                 {
1274                         if (target == null) {
1275                                 source.Emit (ec);
1276                                 return;
1277                         }
1278
1279                         base.EmitStatement(ec);
1280                 }
1281         }
1282
1283         public class Undo
1284         {
1285                 List<Action> undo_actions;
1286
1287                 public void AddTypeContainer (TypeContainer current_container, TypeDefinition tc)
1288                 {
1289                         if (current_container == tc){
1290                                 Console.Error.WriteLine ("Internal error: inserting container into itself");
1291                                 return;
1292                         }
1293
1294                         if (undo_actions == null)
1295                                 undo_actions = new List<Action> ();
1296
1297                         if (current_container.Containers != null)
1298                         {
1299                                 var existing = current_container.Containers.FirstOrDefault (l => l.MemberName.Basename == tc.MemberName.Basename);
1300                                 if (existing != null) {
1301                                         current_container.RemoveContainer (existing);
1302                                         undo_actions.Add (() => current_container.AddTypeContainer (existing));
1303                                 }
1304                         }
1305
1306                         undo_actions.Add (() => current_container.RemoveContainer (tc));
1307                 }
1308
1309                 public void ExecuteUndo ()
1310                 {
1311                         if (undo_actions == null)
1312                                 return;
1313
1314                         foreach (var p in undo_actions){
1315                                 p ();
1316                         }
1317
1318                         undo_actions = null;
1319                 }
1320         }
1321
1322         static class ListenerProxy
1323         {
1324                 static readonly Dictionary<int, ValueModificationHandler> listeners = new Dictionary<int, ValueModificationHandler> ();
1325
1326                 static int counter;
1327
1328                 public static int Register (ValueModificationHandler listener)
1329                 {
1330                         lock (listeners) {
1331                                 var id = counter++;
1332                                 listeners.Add (id, listener);
1333                                 return id;
1334                         }
1335                 }
1336
1337                 public static void Unregister (int listenerId)
1338                 {
1339                         lock (listeners) {
1340                                 listeners.Remove (listenerId);
1341                         }
1342                 }
1343
1344                 public static void ValueChanged (object value, int row, int col, string name, int listenerId)
1345                 {
1346                         ValueModificationHandler action;
1347                         lock (listeners) {
1348                                 if (!listeners.TryGetValue (listenerId, out action))
1349                                         return;
1350                         }
1351
1352                         action (name, row, col, value);
1353                 }
1354         }
1355 }