2 // pending.cs: Pending method implementation
5 // Miguel de Icaza (miguel@gnu.org)
6 // Marek Safar (marek.safar@gmail.com)
8 // Dual licensed under the terms of the MIT X11 or GNU GPL
10 // Copyright 2001, 2002 Ximian, Inc (http://www.ximian.com)
11 // Copyright 2003-2008 Novell, Inc.
12 // Copyright 2011 Xamarin Inc
16 using System.Collections.Generic;
20 using IKVM.Reflection;
21 using IKVM.Reflection.Emit;
23 using System.Reflection;
24 using System.Reflection.Emit;
27 namespace Mono.CSharp {
29 struct TypeAndMethods {
31 public IList<MethodSpec> methods;
34 // Whether it is optional, this is used to allow the explicit/implicit
35 // implementation when a base class already implements an interface.
39 // class X : IA { } class Y : X, IA { IA.Explicit (); }
44 // This flag on the method says `We found a match, but
45 // because it was private, we could not use the match
47 public MethodData [] found;
49 // If a method is defined here, then we always need to
50 // create a proxy for it. This is used when implementing
51 // an interface's indexer with a different IndexerName.
52 public MethodSpec [] need_proxy;
55 struct ProxyMethodContext : IMemberContext
57 readonly TypeContainer container;
59 public ProxyMethodContext (TypeContainer container)
61 this.container = container;
64 public TypeSpec CurrentType {
66 throw new NotImplementedException ();
70 public TypeParameters CurrentTypeParameters {
72 throw new NotImplementedException ();
76 public MemberCore CurrentMemberDefinition {
78 throw new NotImplementedException ();
82 public bool IsObsolete {
88 public bool IsUnsafe {
90 throw new NotImplementedException ();
94 public bool IsStatic {
100 public ModuleContainer Module {
102 return container.Module;
106 public string GetSignatureForError ()
108 throw new NotImplementedException ();
111 public ExtensionMethodCandidates LookupExtensionMethod (string name, int arity)
113 throw new NotImplementedException ();
116 public FullNamedExpression LookupNamespaceOrType (string name, int arity, LookupMode mode, Location loc)
118 throw new NotImplementedException ();
121 public FullNamedExpression LookupNamespaceAlias (string name)
123 throw new NotImplementedException ();
127 public class PendingImplementation
130 /// The container for this PendingImplementation
132 readonly TypeDefinition container;
135 /// This is the array of TypeAndMethods that describes the pending implementations
136 /// (both interfaces and abstract methods in base class)
138 TypeAndMethods [] pending_implementations;
140 PendingImplementation (TypeDefinition container, MissingInterfacesInfo[] missing_ifaces, MethodSpec[] abstract_methods, int total)
142 var type_builder = container.Definition;
144 this.container = container;
145 pending_implementations = new TypeAndMethods [total];
148 if (abstract_methods != null) {
149 int count = abstract_methods.Length;
150 pending_implementations [i].methods = new MethodSpec [count];
151 pending_implementations [i].need_proxy = new MethodSpec [count];
153 pending_implementations [i].methods = abstract_methods;
154 pending_implementations [i].found = new MethodData [count];
155 pending_implementations [i].type = type_builder;
159 foreach (MissingInterfacesInfo missing in missing_ifaces) {
160 var iface = missing.Type;
161 var mi = MemberCache.GetInterfaceMethods (iface);
163 int count = mi.Count;
164 pending_implementations [i].type = iface;
165 pending_implementations [i].optional = missing.Optional;
166 pending_implementations [i].methods = mi;
167 pending_implementations [i].found = new MethodData [count];
168 pending_implementations [i].need_proxy = new MethodSpec [count];
175 return container.Module.Compiler.Report;
179 struct MissingInterfacesInfo {
180 public TypeSpec Type;
181 public bool Optional;
183 public MissingInterfacesInfo (TypeSpec t)
190 static readonly MissingInterfacesInfo [] EmptyMissingInterfacesInfo = new MissingInterfacesInfo [0];
192 static MissingInterfacesInfo [] GetMissingInterfaces (TypeDefinition container)
195 // Interfaces will return all interfaces that the container
196 // implements including any inherited interfaces
198 var impl = container.Definition.Interfaces;
200 if (impl == null || impl.Count == 0)
201 return EmptyMissingInterfacesInfo;
203 var ret = new MissingInterfacesInfo[impl.Count];
205 for (int i = 0; i < ret.Length; i++)
206 ret [i] = new MissingInterfacesInfo (impl [i]);
208 // we really should not get here because Object doesnt implement any
209 // interfaces. But it could implement something internal, so we have
210 // to handle that case.
211 if (container.BaseType == null)
214 var base_impls = container.BaseType.Interfaces;
215 if (base_impls != null) {
216 foreach (TypeSpec t in base_impls) {
217 for (int i = 0; i < ret.Length; i++) {
218 if (t == ret[i].Type) {
219 ret[i].Optional = true;
230 // Factory method: if there are pending implementation methods, we return a PendingImplementation
231 // object, otherwise we return null.
233 // Register method implementations are either abstract methods
234 // flagged as such on the base class or interface methods
236 static public PendingImplementation GetPendingImplementations (TypeDefinition container)
238 TypeSpec b = container.BaseType;
240 var missing_interfaces = GetMissingInterfaces (container);
243 // If we are implementing an abstract class, and we are not
244 // ourselves abstract, and there are abstract methods (C# allows
245 // abstract classes that have no abstract methods), then allocate
248 // We also pre-compute the methods.
250 bool implementing_abstract = ((b != null) && b.IsAbstract && (container.ModFlags & Modifiers.ABSTRACT) == 0);
251 MethodSpec[] abstract_methods = null;
253 if (implementing_abstract){
254 var am = MemberCache.GetNotImplementedAbstractMethods (b);
257 implementing_abstract = false;
259 abstract_methods = new MethodSpec[am.Count];
260 am.CopyTo (abstract_methods, 0);
264 int total = missing_interfaces.Length + (implementing_abstract ? 1 : 0);
268 var pending = new PendingImplementation (container, missing_interfaces, abstract_methods, total);
271 // check for inherited conflicting methods
273 foreach (var p in pending.pending_implementations) {
275 // It can happen for generic interfaces only
277 if (!p.type.IsGeneric)
281 // CLR does not distinguishes between ref and out
283 for (int i = 0; i < p.methods.Count; ++i) {
284 MethodSpec compared_method = p.methods[i];
285 if (compared_method.Parameters.IsEmpty)
288 for (int ii = i + 1; ii < p.methods.Count; ++ii) {
289 MethodSpec tested_method = p.methods[ii];
290 if (compared_method.Name != tested_method.Name)
293 if (p.type != tested_method.DeclaringType)
296 if (!TypeSpecComparer.Override.IsSame (compared_method.Parameters.Types, tested_method.Parameters.Types))
299 bool exact_match = true;
300 bool ref_only_difference = false;
301 var cp = compared_method.Parameters.FixedParameters;
302 var tp = tested_method.Parameters.FixedParameters;
304 for (int pi = 0; pi < cp.Length; ++pi) {
306 // First check exact modifiers match
308 if ((cp[pi].ModFlags & Parameter.Modifier.RefOutMask) == (tp[pi].ModFlags & Parameter.Modifier.RefOutMask))
311 if (((cp[pi].ModFlags | tp[pi].ModFlags) & Parameter.Modifier.RefOutMask) == Parameter.Modifier.RefOutMask) {
312 ref_only_difference = true;
320 if (!exact_match || !ref_only_difference)
323 pending.Report.SymbolRelatedToPreviousError (compared_method);
324 pending.Report.SymbolRelatedToPreviousError (tested_method);
325 pending.Report.Error (767, container.Location,
326 "Cannot implement interface `{0}' with the specified type parameters because it causes method `{1}' to differ on parameter modifiers only",
327 p.type.GetDefinition().GetSignatureForError (), compared_method.GetSignatureForError ());
337 public enum Operation {
339 // If you change this, review the whole InterfaceMethod routine as there
340 // are a couple of assumptions on these three states
342 Lookup, ClearOne, ClearAll
346 /// Whether the specified method is an interface method implementation
348 public MethodSpec IsInterfaceMethod (MemberName name, TypeSpec ifaceType, MethodData method, out MethodSpec ambiguousCandidate, ref bool optional)
350 return InterfaceMethod (name, ifaceType, method, Operation.Lookup, out ambiguousCandidate, ref optional);
353 public void ImplementMethod (MemberName name, TypeSpec ifaceType, MethodData method, bool clear_one, out MethodSpec ambiguousCandidate, ref bool optional)
355 InterfaceMethod (name, ifaceType, method, clear_one ? Operation.ClearOne : Operation.ClearAll, out ambiguousCandidate, ref optional);
359 /// If a method in Type `t' (or null to look in all interfaces
360 /// and the base abstract class) with name `Name', return type `ret_type' and
361 /// arguments `args' implements an interface, this method will
362 /// return the MethodInfo that this method implements.
364 /// If `name' is null, we operate solely on the method's signature. This is for
365 /// instance used when implementing indexers.
367 /// The `Operation op' controls whether to lookup, clear the pending bit, or clear
368 /// all the methods with the given signature.
370 /// The `MethodInfo need_proxy' is used when we're implementing an interface's
371 /// indexer in a class. If the new indexer's IndexerName does not match the one
372 /// that was used in the interface, then we always need to create a proxy for it.
375 public MethodSpec InterfaceMethod (MemberName name, TypeSpec iType, MethodData method, Operation op, out MethodSpec ambiguousCandidate, ref bool optional)
377 ambiguousCandidate = null;
379 if (pending_implementations == null)
382 TypeSpec ret_type = method.method.ReturnType;
383 ParametersCompiled args = method.method.ParameterInfo;
384 bool is_indexer = method.method is Indexer.SetIndexerMethod || method.method is Indexer.GetIndexerMethod;
387 foreach (TypeAndMethods tm in pending_implementations){
388 if (!(iType == null || tm.type == iType))
391 int method_count = tm.methods.Count;
392 for (int i = 0; i < method_count; i++){
399 if (!m.IsAccessor || m.Parameters.IsEmpty)
402 if (name.Name != m.Name)
405 if (m.Arity != name.Arity)
409 if (!TypeSpecComparer.Override.IsEqual (m.Parameters, args))
412 if (!TypeSpecComparer.Override.IsEqual (m.ReturnType, ret_type)) {
413 tm.found[i] = method;
418 // `need_proxy' is not null when we're implementing an
419 // interface indexer and this is Clear(One/All) operation.
421 // If `name' is null, then we do a match solely based on the
422 // signature and not on the name (this is done in the Lookup
423 // for an interface indexer).
425 if (op != Operation.Lookup) {
426 if (m.IsAccessor != method.method.IsAccessor)
429 // If `t != null', then this is an explicitly interface
430 // implementation and we can always clear the method.
431 // `need_proxy' is not null if we're implementing an
432 // interface indexer. In this case, we need to create
433 // a proxy if the implementation's IndexerName doesn't
434 // match the IndexerName in the interface.
435 if (m.DeclaringType.IsInterface && iType == null && name.Name != m.Name) { // TODO: This is very expensive comparison
436 tm.need_proxy[i] = method.method.Spec;
438 tm.methods[i] = null;
441 tm.found [i] = method;
442 optional = tm.optional;
445 if (op == Operation.Lookup && name.ExplicitInterface != null && ambiguousCandidate == null) {
446 ambiguousCandidate = m;
451 // Lookups and ClearOne return
453 if (op != Operation.ClearAll)
457 // If a specific type was requested, we can stop now.
458 if (tm.type == iType)
462 m = ambiguousCandidate;
463 ambiguousCandidate = null;
468 /// C# allows this kind of scenarios:
469 /// interface I { void M (); }
470 /// class X { public void M (); }
471 /// class Y : X, I { }
473 /// For that case, we create an explicit implementation function
476 void DefineProxy (TypeSpec iface, MethodSpec base_method, MethodSpec iface_method)
478 // TODO: Handle nested iface names
480 var ns = iface.MemberDefinition.Namespace;
481 if (string.IsNullOrEmpty (ns))
482 proxy_name = iface.MemberDefinition.Name + "." + iface_method.Name;
484 proxy_name = ns + "." + iface.MemberDefinition.Name + "." + iface_method.Name;
486 var param = iface_method.Parameters;
488 MethodBuilder proxy = container.TypeBuilder.DefineMethod (
490 MethodAttributes.Private |
491 MethodAttributes.HideBySig |
492 MethodAttributes.NewSlot |
493 MethodAttributes.CheckAccessOnOverride |
494 MethodAttributes.Virtual | MethodAttributes.Final,
495 CallingConventions.Standard | CallingConventions.HasThis,
496 base_method.ReturnType.GetMetaInfo (), param.GetMetaInfo ());
498 if (iface_method.IsGeneric) {
499 var gnames = iface_method.GenericDefinition.TypeParameters.Select (l => l.Name).ToArray ();
500 proxy.DefineGenericParameters (gnames);
503 for (int i = 0; i < param.Count; i++) {
504 string name = param.FixedParameters [i].Name;
505 ParameterAttributes attr = ParametersCompiled.GetParameterAttribute (param.FixedParameters [i].ModFlags);
506 proxy.DefineParameter (i + 1, attr, name);
509 int top = param.Count;
510 var ec = new EmitContext (new ProxyMethodContext (container), proxy.GetILGenerator (), null, null);
512 // TODO: GetAllParametersArguments
513 for (int i = 0; i < top; i++)
514 ec.EmitArgumentLoad (i);
516 ec.Emit (OpCodes.Call, base_method);
517 ec.Emit (OpCodes.Ret);
519 container.TypeBuilder.DefineMethodOverride (proxy, (MethodInfo) iface_method.GetMetaInfo ());
523 /// This function tells whether one of our base classes implements
524 /// the given method (which turns out, it is valid to have an interface
525 /// implementation in a base
527 bool BaseImplements (TypeSpec iface_type, MethodSpec mi, out MethodSpec base_method)
530 var base_type = container.BaseType;
533 // Setup filter with no return type to give better error message
534 // about mismatch at return type when the check bellow rejects them
536 var parameters = mi.Parameters;
537 MethodSpec close_match = null;
540 var candidates = MemberCache.FindMembers (base_type, mi.Name, false);
541 if (candidates == null) {
542 base_method = close_match;
546 MethodSpec similar_candidate = null;
547 foreach (var candidate in candidates) {
548 if (candidate.Kind != MemberKind.Method)
551 if (candidate.Arity != mi.Arity)
554 var candidate_param = ((MethodSpec) candidate).Parameters;
555 if (!TypeSpecComparer.Override.IsEqual (parameters.Types, candidate_param.Types))
558 bool modifiers_match = true;
559 for (int i = 0; i < parameters.Count; ++i) {
561 // First check exact ref/out match
563 if ((parameters.FixedParameters[i].ModFlags & Parameter.Modifier.RefOutMask) == (candidate_param.FixedParameters[i].ModFlags & Parameter.Modifier.RefOutMask))
566 modifiers_match = false;
569 // Different in ref/out only
571 if ((parameters.FixedParameters[i].ModFlags & Parameter.Modifier.RefOutMask) != (candidate_param.FixedParameters[i].ModFlags & Parameter.Modifier.RefOutMask)) {
572 if (similar_candidate == null) {
573 if (!candidate.IsPublic)
576 if (!TypeSpecComparer.Override.IsEqual (mi.ReturnType, ((MethodSpec) candidate).ReturnType))
579 // It's used for ref/out ambiguity overload check
580 similar_candidate = (MethodSpec) candidate;
586 similar_candidate = null;
590 if (!modifiers_match)
594 // From this point the candidate is used for detailed error reporting
595 // because it's very close match to what we are looking for
597 var m = (MethodSpec) candidate;
600 if (close_match == null)
606 if (!TypeSpecComparer.Override.IsEqual (mi.ReturnType, m.ReturnType)) {
607 if (close_match == null)
615 if (mi.IsGeneric && !Method.CheckImplementingMethodConstraints (container, m, mi)) {
620 if (base_method != null) {
621 if (similar_candidate != null) {
622 Report.SymbolRelatedToPreviousError (similar_candidate);
623 Report.SymbolRelatedToPreviousError (mi);
624 Report.SymbolRelatedToPreviousError (container);
625 Report.Warning (1956, 1, ((MemberCore) base_method.MemberDefinition).Location,
626 "The interface method `{0}' implementation is ambiguous between following methods: `{1}' and `{2}' in type `{3}'",
627 mi.GetSignatureForError (), base_method.GetSignatureForError (), similar_candidate.GetSignatureForError (), container.GetSignatureForError ());
633 base_type = candidates[0].DeclaringType.BaseType;
634 if (base_type == null) {
635 base_method = close_match;
640 if (!base_method.IsVirtual) {
642 var base_builder = base_method.GetMetaInfo () as MethodBuilder;
643 if (base_builder != null) {
645 // We can avoid creating a proxy if base_method can be marked 'final virtual'. This can
646 // be done for all methods from compiled assembly
648 base_builder.__SetAttributes (base_builder.Attributes | MethodAttributes.Virtual | MethodAttributes.Final | MethodAttributes.NewSlot);
652 DefineProxy (iface_type, base_method, mi);
659 /// Verifies that any pending abstract methods or interface methods
660 /// were implemented.
662 public bool VerifyPendingMethods ()
664 int top = pending_implementations.Length;
668 for (i = 0; i < top; i++){
669 TypeSpec type = pending_implementations [i].type;
671 bool base_implements_type = type.IsInterface &&
672 container.BaseType != null &&
673 container.BaseType.ImplementsInterface (type, false);
675 for (int j = 0; j < pending_implementations [i].methods.Count; ++j) {
676 var mi = pending_implementations[i].methods[j];
680 if (type.IsInterface){
682 pending_implementations [i].need_proxy [j];
684 if (need_proxy != null) {
685 DefineProxy (type, need_proxy, mi);
689 if (pending_implementations [i].optional)
692 MethodSpec candidate;
693 if (base_implements_type || BaseImplements (type, mi, out candidate))
696 if (candidate == null) {
697 MethodData md = pending_implementations [i].found [j];
699 candidate = md.method.Spec;
702 Report.SymbolRelatedToPreviousError (mi);
703 if (candidate != null) {
704 Report.SymbolRelatedToPreviousError (candidate);
705 if (candidate.IsStatic) {
706 Report.Error (736, container.Location,
707 "`{0}' does not implement interface member `{1}' and the best implementing candidate `{2}' is static",
708 container.GetSignatureForError (), mi.GetSignatureForError (), candidate.GetSignatureForError ());
709 } else if ((candidate.Modifiers & Modifiers.PUBLIC) == 0) {
710 Report.Error (737, container.Location,
711 "`{0}' does not implement interface member `{1}' and the best implementing candidate `{2}' is not public",
712 container.GetSignatureForError (), mi.GetSignatureForError (), candidate.GetSignatureForError ());
714 Report.Error (738, container.Location,
715 "`{0}' does not implement interface member `{1}' and the best implementing candidate `{2}' return type `{3}' does not match interface member return type `{4}'",
716 container.GetSignatureForError (), mi.GetSignatureForError (), candidate.GetSignatureForError (),
717 candidate.ReturnType.GetSignatureForError (), mi.ReturnType.GetSignatureForError ());
720 Report.Error (535, container.Location, "`{0}' does not implement interface member `{1}'",
721 container.GetSignatureForError (), mi.GetSignatureForError ());
724 Report.SymbolRelatedToPreviousError (mi);
725 Report.Error (534, container.Location, "`{0}' does not implement inherited abstract member `{1}'",
726 container.GetSignatureForError (), mi.GetSignatureForError ());