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2006-12-16 Chris Toshok <toshok@ximian.com>
[mcs.git] / mcs / pending.cs
blob79c0fb5e24f3469ef33c96939545ae16571cee89
1 //
2 // pending.cs: Pending method implementation
3 //
4 // Author:
5 // Miguel de Icaza (miguel@gnu.org)
6 //
7 // Licensed under the terms of the GNU GPL
8 //
9 // (C) 2001, 2002 Ximian, Inc (http://www.ximian.com)
10 //
11 //
12
13 using System;
14 using System.Collections;
15 using System.Reflection;
16 using System.Reflection.Emit;
17
18 namespace Mono.CSharp {
19
20 struct TypeAndMethods {
21 public Type type;
22 public MethodInfo [] methods;
23
24 //
25 // Whether it is optional, this is used to allow the explicit/implicit
26 // implementation when a base class already implements an interface.
27 //
28 // For example:
29 //
30 // class X : IA { } class Y : X, IA { IA.Explicit (); }
31 //
32 public bool optional;
33
34 // Far from ideal, but we want to avoid creating a copy
35 // of methods above.
36 public Type [][] args;
37
38 //This is used to store the modifiers of arguments
39 public Parameter.Modifier [][] mods;
40
41 //
42 // This flag on the method says `We found a match, but
43 // because it was private, we could not use the match
44 //
45 public bool [] found;
46
47 // If a method is defined here, then we always need to
48 // create a proxy for it. This is used when implementing
49 // an interface's indexer with a different IndexerName.
50 public MethodInfo [] need_proxy;
51
52 //
53 // The name of the indexer (if it exists), precompute set/get, because
54 // they would be recomputed many times inside a loop later on.
55 //
56 public string set_indexer_name;
57 public string get_indexer_name;
58 }
59
60 public class PendingImplementation {
61 /// <summary>
62 /// The container for this PendingImplementation
63 /// </summary>
64 TypeContainer container;
65
66 /// <summary>
67 /// This filter is used by FindMembers, and it is used to
68 /// extract only virtual/abstract fields
69 /// </summary>
70 static MemberFilter virtual_method_filter;
71
72 /// <summary>
73 /// This is the array of TypeAndMethods that describes the pending implementations
74 /// (both interfaces and abstract methods in base class)
75 /// </summary>
76 TypeAndMethods [] pending_implementations;
77
78 static bool IsVirtualFilter (MemberInfo m, object filterCriteria)
79 {
80 MethodInfo mi = m as MethodInfo;
81 return (mi == null) ? false : mi.IsVirtual;
82 }
83
84 /// <summary>
85 /// Inits the virtual_method_filter
86 /// </summary>
87 static PendingImplementation ()
88 {
89 virtual_method_filter = new MemberFilter (IsVirtualFilter);
90 }
91
92 // <remarks>
93 // Returns a list of the abstract methods that are exposed by all of our
94 // bases that we must implement. Notice that this `flattens' the
95 // method search space, and takes into account overrides.
96 // </remarks>
97 static ArrayList GetAbstractMethods (Type t)
98 {
99 ArrayList list = null;
100 bool searching = true;
101 Type current_type = t;
102
103 do {
104 MemberList mi;
105
106 mi = TypeContainer.FindMembers (
107 current_type, MemberTypes.Method,
108 BindingFlags.Public | BindingFlags.NonPublic |
109 BindingFlags.Instance | BindingFlags.DeclaredOnly,
110 virtual_method_filter, null);
111
112 if (current_type == TypeManager.object_type)
113 searching = false;
114 else {
115 current_type = current_type.BaseType;
116 if (!current_type.IsAbstract)
117 searching = false;
118 }
119
120 if (mi.Count == 0)
121 continue;
122
123 if (mi.Count == 1 && !(mi [0] is MethodBase))
124 searching = false;
125 else
126 list = TypeManager.CopyNewMethods (list, mi);
127 } while (searching);
128
129 if (list == null)
130 return null;
131
132 for (int i = 0; i < list.Count; i++){
133 while (list.Count > i && !((MethodInfo) list [i]).IsAbstract)
134 list.RemoveAt (i);
135 }
136
137 if (list.Count == 0)
138 return null;
139
140 return list;
141 }
142
143 PendingImplementation (TypeContainer container, MissingInterfacesInfo [] missing_ifaces, ArrayList abstract_methods, int total)
144 {
145 TypeBuilder type_builder = container.TypeBuilder;
146
147 this.container = container;
148 pending_implementations = new TypeAndMethods [total];
149
150 int i = 0;
151 foreach (MissingInterfacesInfo missing in missing_ifaces){
152 MethodInfo [] mi;
153 Type t = missing.Type;
154
155 if (!t.IsInterface)
156 continue;
157
158 if (t is TypeBuilder){
159 TypeContainer iface;
160
161 iface = TypeManager.LookupInterface (t);
162
163 mi = iface.GetMethods ();
164 } else
165 mi = t.GetMethods ();
166
167 int count = mi.Length;
168 pending_implementations [i].type = t;
169 pending_implementations [i].optional = missing.Optional;
170 pending_implementations [i].methods = mi;
171 pending_implementations [i].args = new Type [count][];
172 pending_implementations [i].mods = new Parameter.Modifier [count][];
173 pending_implementations [i].found = new bool [count];
174 pending_implementations [i].need_proxy = new MethodInfo [count];
175 string indexer_name = TypeManager.IndexerPropertyName (t);
176
177 pending_implementations [i].set_indexer_name = "set_" + indexer_name;
178 pending_implementations [i].get_indexer_name = "get_" + indexer_name;
179
180 int j = 0;
181 foreach (MethodInfo m in mi){
182 pending_implementations [i].args [j] = Type.EmptyTypes;
183 pending_implementations [i].mods [j] = null;
184
185 // If there is a previous error, just ignore
186 if (m == null)
187 continue;
188
189 ParameterData pd = TypeManager.GetParameterData (m);
190 pending_implementations [i].args [j] = pd.Types;
191
192 if (pd.Count > 0){
193 Parameter.Modifier [] pm = new Parameter.Modifier [pd.Count];
194 for (int k = 0; k < pd.Count; k++)
195 pm [k] = pd.ParameterModifier (k);
196 pending_implementations [i].mods [j] = pm;
197 }
198
199 j++;
200 }
201 i++;
202 }
203
204 if (abstract_methods != null){
205 int count = abstract_methods.Count;
206 pending_implementations [i].methods = new MethodInfo [count];
207 pending_implementations [i].need_proxy = new MethodInfo [count];
208
209 abstract_methods.CopyTo (pending_implementations [i].methods, 0);
210 pending_implementations [i].found = new bool [count];
211 pending_implementations [i].args = new Type [count][];
212 pending_implementations [i].mods = new Parameter.Modifier [count][];
213 pending_implementations [i].type = type_builder;
214
215 string indexer_name = TypeManager.IndexerPropertyName (type_builder);
216 pending_implementations [i].set_indexer_name = "set_" + indexer_name;
217 pending_implementations [i].get_indexer_name = "get_" + indexer_name;
218
219 int j = 0;
220 foreach (MemberInfo m in abstract_methods){
221 MethodInfo mi = (MethodInfo) m;
222
223 ParameterData pd = TypeManager.GetParameterData (mi);
224 Type [] types = pd.Types;
225
226 pending_implementations [i].args [j] = types;
227 pending_implementations [i].mods [j] = null;
228 if (pd.Count > 0){
229 Parameter.Modifier [] pm = new Parameter.Modifier [pd.Count];
230 for (int k = 0; k < pd.Count; k++)
231 pm [k] = pd.ParameterModifier (k);
232 pending_implementations [i].mods [j] = pm;
233 }
234
235 j++;
236 }
237 }
238 }
239
240 struct MissingInterfacesInfo {
241 public Type Type;
242 public bool Optional;
243
244 public MissingInterfacesInfo (Type t)
245 {
246 Type = t;
247 Optional = false;
248 }
249 }
250
251 static MissingInterfacesInfo [] EmptyMissingInterfacesInfo = new MissingInterfacesInfo [0];
252
253 static MissingInterfacesInfo [] GetMissingInterfaces (TypeBuilder type_builder)
254 {
255 //
256 // Notice that TypeBuilders will only return the interfaces that the Type
257 // is supposed to implement, not all the interfaces that the type implements.
258 //
259 // Even better -- on MS it returns an empty array, no matter what.
260 //
261 // Completely broken. So we do it ourselves!
262 //
263 Type [] impl = TypeManager.GetExplicitInterfaces (type_builder);
264
265 if (impl == null || impl.Length == 0)
266 return EmptyMissingInterfacesInfo;
267
268 MissingInterfacesInfo [] ret = new MissingInterfacesInfo [impl.Length];
269
270 for (int i = 0; i < impl.Length; i++)
271 ret [i] = new MissingInterfacesInfo (impl [i]);
272
273 // we really should not get here because Object doesnt implement any
274 // interfaces. But it could implement something internal, so we have
275 // to handle that case.
276 if (type_builder.BaseType == null)
277 return ret;
278
279 Type [] base_impls = TypeManager.GetInterfaces (type_builder.BaseType);
280
281 foreach (Type t in base_impls) {
282 for (int i = 0; i < ret.Length; i ++) {
283 if (t == ret [i].Type) {
284 ret [i].Optional = true;
285 break;
286 }
287 }
288 }
289 return ret;
290 }
291
292 //
293 // Factory method: if there are pending implementation methods, we return a PendingImplementation
294 // object, otherwise we return null.
295 //
296 // Register method implementations are either abstract methods
297 // flagged as such on the base class or interface methods
298 //
299 static public PendingImplementation GetPendingImplementations (TypeContainer container)
300 {
301 TypeBuilder type_builder = container.TypeBuilder;
302 MissingInterfacesInfo [] missing_interfaces;
303 Type b = type_builder.BaseType;
304
305 missing_interfaces = GetMissingInterfaces (type_builder);
306
307 //
308 // If we are implementing an abstract class, and we are not
309 // ourselves abstract, and there are abstract methods (C# allows
310 // abstract classes that have no abstract methods), then allocate
311 // one slot.
312 //
313 // We also pre-compute the methods.
314 //
315 bool implementing_abstract = ((b != null) && b.IsAbstract && !type_builder.IsAbstract);
316 ArrayList abstract_methods = null;
317
318 if (implementing_abstract){
319 abstract_methods = GetAbstractMethods (b);
320
321 if (abstract_methods == null)
322 implementing_abstract = false;
323 }
324
325 int total = missing_interfaces.Length + (implementing_abstract ? 1 : 0);
326 if (total == 0)
327 return null;
328
329 return new PendingImplementation (container, missing_interfaces, abstract_methods, total);
330 }
331
332 public enum Operation {
333 //
334 // If you change this, review the whole InterfaceMethod routine as there
335 // are a couple of assumptions on these three states
336 //
337 Lookup, ClearOne, ClearAll
338 }
339
340 /// <summary>
341 /// Whether the specified method is an interface method implementation
342 /// </summary>
343 public MethodInfo IsInterfaceMethod (Type t, string name, Type ret_type, ParameterData args)
344 {
345 return InterfaceMethod (t, name, ret_type, args, Operation.Lookup, null);
346 }
347
348 public MethodInfo IsInterfaceIndexer (Type t, Type ret_type, ParameterData args)
349 {
350 return InterfaceMethod (t, null, ret_type, args, Operation.Lookup, null);
351 }
352
353 public void ImplementMethod (Type t, string name, Type ret_type, ParameterData args, bool clear_one)
354 {
355 InterfaceMethod (t, name, ret_type, args,
356 clear_one ? Operation.ClearOne : Operation.ClearAll, null);
357 }
358
359 public void ImplementIndexer (Type t, MethodInfo mi, Type ret_type, ParameterData args, bool clear_one)
360 {
361 InterfaceMethod (t, null, ret_type, args,
362 clear_one ? Operation.ClearOne : Operation.ClearAll, mi);
363 }
364
365 /// <remarks>
366 /// If a method in Type `t' (or null to look in all interfaces
367 /// and the base abstract class) with name `Name', return type `ret_type' and
368 /// arguments `args' implements an interface, this method will
369 /// return the MethodInfo that this method implements.
370 ///
371 /// If `name' is null, we operate solely on the method's signature. This is for
372 /// instance used when implementing indexers.
373 ///
374 /// The `Operation op' controls whether to lookup, clear the pending bit, or clear
375 /// all the methods with the given signature.
376 ///
377 /// The `MethodInfo need_proxy' is used when we're implementing an interface's
378 /// indexer in a class. If the new indexer's IndexerName does not match the one
379 /// that was used in the interface, then we always need to create a proxy for it.
380 ///
381 /// </remarks>
382 public MethodInfo InterfaceMethod (Type t, string name, Type ret_type, ParameterData args,
383 Operation op, MethodInfo need_proxy)
384 {
385 int arg_len = args.Count;
386
387 if (pending_implementations == null)
388 return null;
389
390 foreach (TypeAndMethods tm in pending_implementations){
391 if (!(t == null || tm.type == t))
392 continue;
393
394 int method_count = tm.methods.Length;
395 MethodInfo m;
396 for (int i = 0; i < method_count; i++){
397 m = tm.methods [i];
398
399 if (m == null)
400 continue;
401
402 string mname = TypeManager.GetMethodName (m);
403
404 //
405 // `need_proxy' is not null when we're implementing an
406 // interface indexer and this is Clear(One/All) operation.
407 //
408 // If `name' is null, then we do a match solely based on the
409 // signature and not on the name (this is done in the Lookup
410 // for an interface indexer).
411 //
412 if (name == null){
413 if (mname != tm.get_indexer_name && mname != tm.set_indexer_name)
414 continue;
415 } else if ((need_proxy == null) && (name != mname))
416 continue;
417
418 if (!TypeManager.IsEqual (ret_type, m.ReturnType) &&
419 !(ret_type == null && m.ReturnType == TypeManager.void_type) &&
420 !(m.ReturnType == null && ret_type == TypeManager.void_type))
421 continue;
422
423 //
424 // Check if we have the same parameters
425 //
426
427 if (tm.args [i] == null && arg_len != 0)
428 continue;
429 if (tm.args [i] != null && tm.args [i].Length != arg_len)
430 continue;
431
432 int j;
433
434 for (j = 0; j < arg_len; j++) {
435 if (!TypeManager.IsEqual (tm.args [i][j], args.ParameterType (j)))
436 break;
437 if (tm.mods [i][j] == args.ParameterModifier (j))
438 continue;
439 // The modifiers are different, but if one of them
440 // is a PARAMS modifier, and the other isn't, ignore
441 // the difference.
442 if (tm.mods [i][j] != Parameter.Modifier.PARAMS &&
443 args.ParameterModifier (j) != Parameter.Modifier.PARAMS)
444 break;
445 }
446 if (j != arg_len)
447 continue;
448
449 if (op != Operation.Lookup){
450 // If `t != null', then this is an explicitly interface
451 // implementation and we can always clear the method.
452 // `need_proxy' is not null if we're implementing an
453 // interface indexer. In this case, we need to create
454 // a proxy if the implementation's IndexerName doesn't
455 // match the IndexerName in the interface.
456 bool name_matches = false;
457 if (name == mname || mname == tm.get_indexer_name || mname == tm.set_indexer_name)
458 name_matches = true;
459
460 if ((t == null) && (need_proxy != null) && !name_matches)
461 tm.need_proxy [i] = need_proxy;
462 else
463 tm.methods [i] = null;
464 }
465 tm.found [i] = true;
466
467 //
468 // Lookups and ClearOne return
469 //
470 if (op != Operation.ClearAll)
471 return m;
472 }
473
474 // If a specific type was requested, we can stop now.
475 if (tm.type == t)
476 return null;
477 }
478 return null;
479 }
480
481 /// <summary>
482 /// C# allows this kind of scenarios:
483 /// interface I { void M (); }
484 /// class X { public void M (); }
485 /// class Y : X, I { }
486 ///
487 /// For that case, we create an explicit implementation function
488 /// I.M in Y.
489 /// </summary>
490 void DefineProxy (Type iface, MethodInfo base_method, MethodInfo iface_method,
491 Type [] args)
492 {
493 MethodBuilder proxy;
494
495 string proxy_name = SimpleName.RemoveGenericArity (iface.Name) + '.' + iface_method.Name;
496
497 proxy = container.TypeBuilder.DefineMethod (
498 proxy_name,
499 MethodAttributes.HideBySig |
500 MethodAttributes.NewSlot |
501 MethodAttributes.Virtual,
502 CallingConventions.Standard | CallingConventions.HasThis,
503 base_method.ReturnType, args);
504
505 ParameterData pd = TypeManager.GetParameterData (iface_method);
506 proxy.DefineParameter (0, ParameterAttributes.None, "");
507 for (int i = 0; i < pd.Count; i++) {
508 string name = pd.ParameterName (i);
509 ParameterAttributes attr = Parameter.GetParameterAttributes (pd.ParameterModifier (i));
510 proxy.DefineParameter (i + 1, attr, name);
511 }
512
513 int top = args.Length;
514 ILGenerator ig = proxy.GetILGenerator ();
515
516 for (int i = 0; i <= top; i++)
517 ParameterReference.EmitLdArg (ig, i);
518
519 ig.Emit (OpCodes.Call, base_method);
520 ig.Emit (OpCodes.Ret);
521
522 container.TypeBuilder.DefineMethodOverride (proxy, iface_method);
523 }
524
525 /// <summary>
526 /// This function tells whether one of our base classes implements
527 /// the given method (which turns out, it is valid to have an interface
528 /// implementation in a base
529 /// </summary>
530 bool BaseImplements (Type iface_type, MethodInfo mi)
531 {
532 MethodSignature ms;
533
534 Type [] args = TypeManager.GetParameterData (mi).Types;
535 ms = new MethodSignature (mi.Name, mi.ReturnType, args);
536 MemberList list = TypeContainer.FindMembers (
537 container.TypeBuilder.BaseType, MemberTypes.Method | MemberTypes.Property,
538 BindingFlags.Public | BindingFlags.Instance,
539 MethodSignature.method_signature_filter, ms);
540
541 if (list.Count == 0)
542 return false;
543
544 if (TypeManager.ImplementsInterface (container.TypeBuilder.BaseType, iface_type))
545 return true;
546
547 //
548 // FIXME: We should be creating fewer proxies. The runtime can handle most cases.
549 // At worst, if we can't avoid creating the proxy, we may need to make the
550 // proxy use Callvirt.
551 //
552 MethodInfo base_method = (MethodInfo) list [0];
553
554 if (base_method.DeclaringType.IsInterface)
555 return false;
556
557 if (!base_method.IsAbstract && !base_method.IsVirtual)
558 DefineProxy (iface_type, base_method, mi, args);
559
560 return true;
561 }
562
563 /// <summary>
564 /// Verifies that any pending abstract methods or interface methods
565 /// were implemented.
566 /// </summary>
567 public bool VerifyPendingMethods ()
568 {
569 int top = pending_implementations.Length;
570 bool errors = false;
571 int i;
572
573 for (i = 0; i < top; i++){
574 Type type = pending_implementations [i].type;
575 int j = 0;
576
577 bool base_implements_type = type.IsInterface &&
578 container.TypeBuilder.BaseType != null &&
579 TypeManager.ImplementsInterface (container.TypeBuilder.BaseType, type);
580
581 foreach (MethodInfo mi in pending_implementations [i].methods){
582 if (mi == null)
583 continue;
584
585 if (type.IsInterface){
586 MethodInfo need_proxy =
587 pending_implementations [i].need_proxy [j];
588
589 if (need_proxy != null) {
590 Type [] args = TypeManager.GetParameterData (mi).Types;
591 DefineProxy (type, need_proxy, mi, args);
592 continue;
593 }
594
595 if (base_implements_type || BaseImplements (type, mi))
596 continue;
597
598 if (pending_implementations [i].optional)
599 continue;
600
601 Report.SymbolRelatedToPreviousError (mi);
602 if (pending_implementations [i].found [j]) {
603 if (mi.IsSpecialName) {
604 string name = TypeManager.CSharpName (mi.DeclaringType) + '.' + mi.Name.Substring (4);
605 Report.Error (551, container.Location, "Explicit interface implementation `{0}.{1}' is missing accessor `{2}'",
606 container.GetSignatureForError (), name, TypeManager.CSharpSignature (mi, true));
607 } else {
608 string[] methodLabel = TypeManager.CSharpSignature (mi).Split ('.');
609 Report.Error (536, container.Location,
610 "`{0}' does not implement interface member `{1}'. `{2}.{3}' " +
611 "is either static, not public, or has the wrong return type",
612 container.Name, TypeManager.CSharpSignature (mi),
613 container.Name, methodLabel[methodLabel.Length - 1]);
614 }
615 }
616 else {
617 Report.Error (535, container.Location, "`{0}' does not implement interface member `{1}'",
618 container.GetSignatureForError (), TypeManager.CSharpSignature (mi));
619 }
620 } else {
621 Report.Error (534, container.Location, "`{0}' does not implement inherited abstract member `{1}'",
622 container.GetSignatureForError (), TypeManager.CSharpSignature (mi, true));
623 }
624 errors = true;
625 j++;
626 }
627 }
628 return errors;
629 }
630 } /* end of class */
631 }
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