//
// pending.cs: Pending method implementation
//
// Author:
// Miguel de Icaza (miguel@gnu.org)
//
// Licensed under the terms of the GNU GPL
//
// (C) 2001, 2002 Ximian, Inc (http://www.ximian.com)
//
//
using System;
using System.Collections;
using System.Reflection;
using System.Reflection.Emit;
namespace Mono.CSharp {
struct TypeAndMethods {
public Type type;
public MethodInfo [] methods;
//
// Whether it is optional, this is used to allow the explicit/implicit
// implementation when a parent class already implements an interface.
//
// For example:
//
// class X : IA { } class Y : X, IA { IA.Explicit (); }
//
public bool optional;
// Far from ideal, but we want to avoid creating a copy
// of methods above.
public Type [][] args;
//
// This flag on the method says `We found a match, but
// because it was private, we could not use the match
//
public bool [] found;
// If a method is defined here, then we always need to
// create a proxy for it. This is used when implementing
// an interface's indexer with a different IndexerName.
public MethodInfo [] need_proxy;
//
// The name of the indexer (if it exists), precompute set/get, because
// they would be recomputed many times inside a loop later on.
//
public string set_indexer_name;
public string get_indexer_name;
}
public class PendingImplementation {
///
/// The container for this PendingImplementation
///
TypeContainer container;
///
/// This filter is used by FindMembers, and it is used to
/// extract only virtual/abstract fields
///
static MemberFilter virtual_method_filter;
///
/// This is the array of TypeAndMethods that describes the pending implementations
/// (both interfaces and abstract methods in parent class)
///
TypeAndMethods [] pending_implementations;
static bool IsVirtualFilter (MemberInfo m, object filterCriteria)
{
MethodInfo mi = m as MethodInfo;
return (mi == null) ? false : mi.IsVirtual;
}
///
/// Inits the virtual_method_filter
///
static PendingImplementation ()
{
virtual_method_filter = new MemberFilter (IsVirtualFilter);
}
//
// Returns a list of the abstract methods that are exposed by all of our
// parents that we must implement. Notice that this `flattens' the
// method search space, and takes into account overrides.
//
static ArrayList GetAbstractMethods (Type t)
{
ArrayList list = null;
bool searching = true;
Type current_type = t;
do {
MemberList mi;
mi = TypeContainer.FindMembers (
current_type, MemberTypes.Method,
BindingFlags.Public | BindingFlags.Instance |
BindingFlags.DeclaredOnly,
virtual_method_filter, null);
if (current_type == TypeManager.object_type)
searching = false;
else {
current_type = current_type.BaseType;
if (!current_type.IsAbstract)
searching = false;
}
if (mi.Count == 0)
continue;
if (mi.Count == 1 && !(mi [0] is MethodBase))
searching = false;
else
list = TypeManager.CopyNewMethods (list, mi);
} while (searching);
if (list == null)
return null;
for (int i = 0; i < list.Count; i++){
while (list.Count > i && !((MethodInfo) list [i]).IsAbstract)
list.RemoveAt (i);
}
if (list.Count == 0)
return null;
return list;
}
PendingImplementation (TypeContainer container, MissingInterfacesInfo [] missing_ifaces, ArrayList abstract_methods, int total)
{
TypeBuilder type_builder = container.TypeBuilder;
this.container = container;
pending_implementations = new TypeAndMethods [total];
int i = 0;
foreach (MissingInterfacesInfo missing in missing_ifaces){
MethodInfo [] mi;
Type t = missing.Type;
if (t is TypeBuilder){
Interface iface;
iface = TypeManager.LookupInterface (t);
mi = iface.GetMethods ();
} else
mi = t.GetMethods ();
int count = mi.Length;
pending_implementations [i].type = t;
pending_implementations [i].optional = missing.Optional;
pending_implementations [i].methods = mi;
pending_implementations [i].args = new Type [count][];
pending_implementations [i].found = new bool [count];
pending_implementations [i].need_proxy = new MethodInfo [count];
string indexer_name = TypeManager.IndexerPropertyName (t);
pending_implementations [i].set_indexer_name = "set_" + indexer_name;
pending_implementations [i].get_indexer_name = "get_" + indexer_name;
int j = 0;
foreach (MethodInfo m in mi){
Type [] types = TypeManager.GetArgumentTypes (m);
pending_implementations [i].args [j] = types;
j++;
}
i++;
}
if (abstract_methods != null){
int count = abstract_methods.Count;
pending_implementations [i].methods = new MethodInfo [count];
pending_implementations [i].need_proxy = new MethodInfo [count];
abstract_methods.CopyTo (pending_implementations [i].methods, 0);
pending_implementations [i].found = new bool [count];
pending_implementations [i].args = new Type [count][];
pending_implementations [i].type = type_builder;
string indexer_name = TypeManager.IndexerPropertyName (type_builder);
pending_implementations [i].set_indexer_name = "set_" + indexer_name;
pending_implementations [i].get_indexer_name = "get_" + indexer_name;
int j = 0;
foreach (MemberInfo m in abstract_methods){
MethodInfo mi = (MethodInfo) m;
Type [] types = TypeManager.GetArgumentTypes (mi);
pending_implementations [i].args [j] = types;
j++;
}
}
}
struct MissingInterfacesInfo {
public Type Type;
public bool Optional;
public MissingInterfacesInfo (Type t)
{
Type = t;
Optional = false;
}
}
static MissingInterfacesInfo [] EmptyMissingInterfacesInfo = new MissingInterfacesInfo [0];
static MissingInterfacesInfo [] GetMissingInterfaces (TypeBuilder type_builder)
{
//
// Notice that TypeBuilders will only return the interfaces that the Type
// is supposed to implement, not all the interfaces that the type implements.
//
// Even better -- on MS it returns an empty array, no matter what.
//
// Completely broken. So we do it ourselves!
//
TypeExpr [] impl = TypeManager.GetExplicitInterfaces (type_builder);
if (impl == null || impl.Length == 0)
return EmptyMissingInterfacesInfo;
MissingInterfacesInfo [] ret = new MissingInterfacesInfo [impl.Length];
for (int i = 0; i < impl.Length; i++)
ret [i] = new MissingInterfacesInfo (impl [i].Type);
// we really should not get here because Object doesnt implement any
// interfaces. But it could implement something internal, so we have
// to handle that case.
if (type_builder.BaseType == null)
return ret;
TypeExpr [] parent_impls = TypeManager.GetInterfaces (type_builder.BaseType);
foreach (TypeExpr te in parent_impls) {
Type t = te.Type;
for (int i = 0; i < ret.Length; i ++) {
if (t == ret [i].Type) {
ret [i].Optional = true;
break;
}
}
}
return ret;
}
//
// Factory method: if there are pending implementation methods, we return a PendingImplementation
// object, otherwise we return null.
//
// Register method implementations are either abstract methods
// flagged as such on the base class or interface methods
//
static public PendingImplementation GetPendingImplementations (TypeContainer container)
{
TypeBuilder type_builder = container.TypeBuilder;
MissingInterfacesInfo [] missing_interfaces;
Type b = type_builder.BaseType;
missing_interfaces = GetMissingInterfaces (type_builder);
//
// If we are implementing an abstract class, and we are not
// ourselves abstract, and there are abstract methods (C# allows
// abstract classes that have no abstract methods), then allocate
// one slot.
//
// We also pre-compute the methods.
//
bool implementing_abstract = ((b != null) && b.IsAbstract && !type_builder.IsAbstract);
ArrayList abstract_methods = null;
if (implementing_abstract){
abstract_methods = GetAbstractMethods (b);
if (abstract_methods == null)
implementing_abstract = false;
}
int total = missing_interfaces.Length + (implementing_abstract ? 1 : 0);
if (total == 0)
return null;
return new PendingImplementation (container, missing_interfaces, abstract_methods, total);
}
public enum Operation {
//
// If you change this, review the whole InterfaceMethod routine as there
// are a couple of assumptions on these three states
//
Lookup, ClearOne, ClearAll
}
///
/// Whether the specified method is an interface method implementation
///
public MethodInfo IsInterfaceMethod (Type t, string name, Type ret_type, Type [] args)
{
return InterfaceMethod (t, name, ret_type, args, Operation.Lookup, null);
}
public MethodInfo IsInterfaceIndexer (Type t, Type ret_type, Type [] args)
{
return InterfaceMethod (t, null, ret_type, args, Operation.Lookup, null);
}
public void ImplementMethod (Type t, string name, Type ret_type, Type [] args, bool clear_one)
{
InterfaceMethod (t, name, ret_type, args,
clear_one ? Operation.ClearOne : Operation.ClearAll, null);
}
public void ImplementIndexer (Type t, MethodInfo mi, Type ret_type, Type [] args, bool clear_one)
{
InterfaceMethod (t, null, ret_type, args,
clear_one ? Operation.ClearOne : Operation.ClearAll, mi);
}
///
/// If a method in Type `t' (or null to look in all interfaces
/// and the base abstract class) with name `Name', return type `ret_type' and
/// arguments `args' implements an interface, this method will
/// return the MethodInfo that this method implements.
///
/// If `name' is null, we operate solely on the method's signature. This is for
/// instance used when implementing indexers.
///
/// The `Operation op' controls whether to lookup, clear the pending bit, or clear
/// all the methods with the given signature.
///
/// The `MethodInfo need_proxy' is used when we're implementing an interface's
/// indexer in a class. If the new indexer's IndexerName does not match the one
/// that was used in the interface, then we always need to create a proxy for it.
///
///
public MethodInfo InterfaceMethod (Type t, string name, Type ret_type, Type [] args,
Operation op, MethodInfo need_proxy)
{
int arg_len = args.Length;
if (pending_implementations == null)
return null;
foreach (TypeAndMethods tm in pending_implementations){
if (!(t == null || tm.type == t))
continue;
int method_count = tm.methods.Length;
MethodInfo m;
for (int i = 0; i < method_count; i++){
m = tm.methods [i];
if (m == null)
continue;
//
// `need_proxy' is not null when we're implementing an
// interface indexer and this is Clear(One/All) operation.
//
// If `name' is null, then we do a match solely based on the
// signature and not on the name (this is done in the Lookup
// for an interface indexer).
//
if (name == null){
if (m.Name != tm.get_indexer_name && m.Name != tm.set_indexer_name)
continue;
} else if ((need_proxy == null) && (name != m.Name))
continue;
if (!TypeManager.IsEqual (ret_type, m.ReturnType)){
if (!((ret_type == null && m.ReturnType == TypeManager.void_type) ||
(m.ReturnType == null && ret_type == TypeManager.void_type)))
continue;
}
//
// Check if we have the same parameters
//
if (tm.args [i].Length != arg_len)
continue;
int j, top = args.Length;
bool fail = false;
for (j = 0; j < top; j++){
if (!TypeManager.IsEqual (tm.args [i][j], args[j])){
fail = true;
break;
}
}
if (fail)
continue;
if (op != Operation.Lookup){
// If `t != null', then this is an explicitly interface
// implementation and we can always clear the method.
// `need_proxy' is not null if we're implementing an
// interface indexer. In this case, we need to create
// a proxy if the implementation's IndexerName doesn't
// match the IndexerName in the interface.
bool name_matches = false;
if (name == m.Name || m.Name == tm.get_indexer_name || m.Name == tm.set_indexer_name)
name_matches = true;
if ((t == null) && (need_proxy != null) && !name_matches)
tm.need_proxy [i] = need_proxy;
else
tm.methods [i] = null;
}
tm.found [i] = true;
//
// Lookups and ClearOne return
//
if (op != Operation.ClearAll)
return m;
}
// If a specific type was requested, we can stop now.
if (tm.type == t)
return null;
}
return null;
}
///
/// C# allows this kind of scenarios:
/// interface I { void M (); }
/// class X { public void M (); }
/// class Y : X, I { }
///
/// For that case, we create an explicit implementation function
/// I.M in Y.
///
void DefineProxy (Type iface, MethodInfo parent_method, MethodInfo iface_method,
Type [] args)
{
MethodBuilder proxy;
string proxy_name = iface.Name + "." + iface_method.Name;
proxy = container.TypeBuilder.DefineMethod (
proxy_name,
MethodAttributes.HideBySig |
MethodAttributes.NewSlot |
MethodAttributes.Virtual,
CallingConventions.Standard | CallingConventions.HasThis,
parent_method.ReturnType, args);
int top = args.Length;
ILGenerator ig = proxy.GetILGenerator ();
ig.Emit (OpCodes.Ldarg_0);
for (int i = 0; i < top; i++){
switch (i){
case 0:
ig.Emit (OpCodes.Ldarg_1); break;
case 1:
ig.Emit (OpCodes.Ldarg_2); break;
case 2:
ig.Emit (OpCodes.Ldarg_3); break;
default:
ig.Emit (OpCodes.Ldarg, i - 1); break;
}
}
ig.Emit (OpCodes.Call, parent_method);
ig.Emit (OpCodes.Ret);
container.TypeBuilder.DefineMethodOverride (proxy, iface_method);
}
///
/// This function tells whether one of our parent classes implements
/// the given method (which turns out, it is valid to have an interface
/// implementation in a parent
///
bool ParentImplements (Type iface_type, MethodInfo mi)
{
MethodSignature ms;
Type [] args = TypeManager.GetArgumentTypes (mi);
ms = new MethodSignature (mi.Name, mi.ReturnType, args);
MemberList list = TypeContainer.FindMembers (
container.TypeBuilder.BaseType, MemberTypes.Method | MemberTypes.Property,
BindingFlags.Public | BindingFlags.Instance,
MethodSignature.method_signature_filter, ms);
if (list.Count == 0)
return false;
MethodInfo parent = (MethodInfo) list [0];
if (!parent.IsAbstract)
DefineProxy (iface_type, parent, mi, args);
return true;
}
///
/// Verifies that any pending abstract methods or interface methods
/// were implemented.
///
public bool VerifyPendingMethods ()
{
int top = pending_implementations.Length;
bool errors = false;
int i;
for (i = 0; i < top; i++){
Type type = pending_implementations [i].type;
int j = 0;
foreach (MethodInfo mi in pending_implementations [i].methods){
if (mi == null)
continue;
if (type.IsInterface){
MethodInfo need_proxy =
pending_implementations [i].need_proxy [j];
if (need_proxy != null) {
Type [] args = TypeManager.GetArgumentTypes (mi);
DefineProxy (type, need_proxy, mi, args);
continue;
}
if (ParentImplements (type, mi))
continue;
if (pending_implementations [i].optional)
continue;
if (pending_implementations [i].found [j]) {
string[] methodLabel = TypeManager.CSharpSignature (mi).Split ('.');
Report.Error (536, container.Location, "'{0}' does not implement interface member '{1}'. '{2}.{3}' is either static, not public, or has the wrong return type",
container.Name, TypeManager.CSharpSignature (mi), container.Name, methodLabel[methodLabel.Length - 1]);
}
else {
Report.Error (535, container.Location, "'{0}' does not implement interface member '{1}'",
container.Name, TypeManager.CSharpSignature (mi));
}
} else {
Report.Error (534, container.Location, "'{0}' does not implement inherited abstract member '{1}'",
container.Name, TypeManager.CSharpSignature (mi));
}
errors = true;
j++;
}
}
return errors;
}
} /* end of class */
}