anonymous.cs

C#编译器源代码。Micorsoft开放源代码

//
// anonymous.cs: Support for anonymous methods
//
// Author:
//   Miguel de Icaza ([e-mail])
//
// (C) 2003, 2004 Novell, Inc.
//
// TODO: Ideally, we should have the helper classes emited as a hierarchy to map
// their nesting, and have the visibility set to private, instead of NestedAssembly
//
//
//

using System;
using System.Text;
using System.Collections;
using System.Reflection;
using System.Reflection.Emit;

namespace Mono.CSharp {

	public abstract class AnonymousContainer : Expression
	{
		// Used to generate unique method names.
		protected static int anonymous_method_count;
		    
		// An array list of AnonymousMethodParameter or null
		public Parameters Parameters;

		//
		// The block that makes up the body for the anonymous mehtod
		//
		public ToplevelBlock Block;

		//
		// The container block for this anonymous method.
		//
		public Block ContainingBlock;

		//
		// The implicit method we create
		//
		public Method method;

		protected MethodInfo invoke_mb;
		
		// The emit context for the anonymous method
		public EmitContext aec;
		public InternalParameters amp;
		protected bool unreachable;

		//
		// The modifiers applied to the method, we aggregate them
		//
		protected int method_modifiers = Modifiers.PRIVATE;
		
		//
		// During the resolve stage of the anonymous method body,
		// we discover the actual scope where we are hosted, or
		// null to host the method in the same class
		//
		public ScopeInfo Scope;

		//
		// Points to our container anonymous method if its present
		//
		public AnonymousContainer ContainerAnonymousMethod;	

		protected AnonymousContainer (Parameters parameters, ToplevelBlock container,
					      ToplevelBlock block, Location l)
		{
			Parameters = parameters;
			Block = block;
			loc = l;

			//
			// The order is important: this setups the CaptureContext tree hierarchy.
			//
			if (container == null) {
				Report.Error (1706, l, "Anonymous methods are not allowed in attribute declaration");
				return;
			}
			container.SetHaveAnonymousMethods (l, this);
			block.SetHaveAnonymousMethods (l, this);
		}

		protected AnonymousContainer (Parameters parameters, ToplevelBlock container,
					      Location l):
			this (parameters, container, new ToplevelBlock (container, parameters, l), l)
		{
		}

		public override Expression DoResolve (EmitContext ec)
		{
			//
			// Set class type, set type
			//

			eclass = ExprClass.Value;
			
			//
			// This hack means `The type is not accessible
			// anywhere', we depend on special conversion
			// rules.
			// 
			type = TypeManager.anonymous_method_type;

			return this;
		}

		protected abstract bool CreateMethodHost (EmitContext ec);

		public abstract void CreateScopeType (EmitContext ec, ScopeInfo scope);

		public abstract bool IsIterator {
			get;
		}
	}

	public class AnonymousMethod : AnonymousContainer
	{
		public AnonymousMethod (Parameters parameters, ToplevelBlock container,
					ToplevelBlock block, Location l)
			: base (parameters, container, block, l)
		{
		}

		public override bool IsIterator {
			get { return false; }
		}

		public override void Emit (EmitContext ec)
		{
			// nothing, as we only exist to not do anything.
		}

		//
		// Creates the host for the anonymous method
		//
		protected override bool CreateMethodHost (EmitContext ec)
		{
			//
			// Crude hack follows: we replace the TypeBuilder during the
			// definition to get the method hosted in the right class
			//
			
			TypeBuilder current_type = ec.TypeContainer.TypeBuilder;
			TypeBuilder type_host = (Scope == null ) // || Scope.ScopeTypeBuilder == null)
				? current_type : Scope.ScopeTypeBuilder;

			if (current_type == null)
				throw new Exception ("The current_type is null");
			
			if (type_host == null)
				throw new Exception (String.Format ("Type host is null, Scope is {0}", Scope == null ? "null" : "Not null"));

			if (current_type != type_host)
				method_modifiers = Modifiers.INTERNAL;

			if (current_type == type_host && ec.IsStatic){
				method_modifiers |= Modifiers.STATIC;
				current_type = null;
			} 

			method = new Method (
				(TypeContainer) ec.TypeContainer,
				new TypeExpression (invoke_mb.ReturnType, loc),
				method_modifiers, false, new MemberName ("<#AnonymousMethod>" + anonymous_method_count++, loc),
				Parameters, null);
			method.Block = Block;
			
			//
			// Swap the TypeBuilder while we define the method, then restore
			//
			if (current_type != null)
				ec.TypeContainer.TypeBuilder = type_host;
			bool res = method.Define ();
			if (current_type != null)
				ec.TypeContainer.TypeBuilder = current_type;
			return res;
		}
		
		void Error_ParameterMismatch (Type t)
		{
			Report.Error (1661, loc, "Anonymous method could not be converted to delegate `" +
				      "{0}' since there is a parameter mismatch", t);
		}

		//
		// Returns true if this anonymous method can be implicitly
		// converted to the delegate type `delegate_type'
		//
		public Expression Compatible (EmitContext ec, Type delegate_type, bool probe)
		{
			//
			// At this point its the first time we know the return type that is 
			// needed for the anonymous method.  We create the method here.
			//

			invoke_mb = (MethodInfo) Delegate.GetInvokeMethod (ec, delegate_type, loc);
			ParameterData invoke_pd = TypeManager.GetParameterData (invoke_mb);

			if (Parameters == null){
				int i, j;
				
				//
				// We provide a set of inaccessible parameters
				//
				int params_idx = -1;
				for (i = 0; i < invoke_pd.Count; i++){
					if (invoke_pd.ParameterModifier (i) == Parameter.Modifier.PARAMS)
						params_idx = i;
				}
				int n = invoke_pd.Count - (params_idx != -1 ? 1 : 0);
				Parameter [] fixedpars = new Parameter [n];
				
				for (i =  j = 0; i < invoke_pd.Count; i++){
					if (invoke_pd.ParameterModifier (i) == Parameter.Modifier.PARAMS)
						continue;
					fixedpars [j] = new Parameter (
						new TypeExpression (invoke_pd.ParameterType (i), loc),
						"+" + j, invoke_pd.ParameterModifier (i), null, loc);
					j++;
				}
				
				Parameter variable = null;
				if (params_idx != -1){
					variable = new Parameter (
						new TypeExpression (invoke_pd.ParameterType (params_idx), loc),
						"+" + params_idx, invoke_pd.ParameterModifier (params_idx), null, loc);
				}

				Parameters = new Parameters (fixedpars, variable);
			}
			
			//
			// First, parameter types of `delegate_type' must be compatible
			// with the anonymous method.
			//
			amp = new InternalParameters (Parameters.GetParameterInfo (ec), Parameters);
			
			if (amp.Count != invoke_pd.Count){
				if (!probe){
					Report.Error (1593, loc, "Delegate `{0}' does not take `{1}' arguments",
						TypeManager.CSharpName (delegate_type), amp.Count);
					Error_ParameterMismatch (delegate_type);
				}
				return null;
			}
			
			for (int i = 0; i < amp.Count; i++){
				Parameter.Modifier amp_mod = amp.ParameterModifier (i);

				if (!probe) {
					if ((amp_mod & (Parameter.Modifier.OUT | Parameter.Modifier.REF)) != 0){
						Report.Error (1677, loc, "Parameter `{0}' should not be declared with the `{1}' keyword", 
							i+1, amp.ModifierDesc (i));
						Error_ParameterMismatch (delegate_type);
						return null;
					}

					if (amp_mod != invoke_pd.ParameterModifier (i)){
						Report.Error (1676, loc, "Parameter `{0}' must be declared with the `{1}' keyword",
							i+1, Parameter.GetModifierSignature (invoke_pd.ParameterModifier (i)));
						Error_ParameterMismatch (delegate_type);
						return null;
					}
				
					if (amp.ParameterType (i) != invoke_pd.ParameterType (i)){
						Report.Error (1678, loc, "Parameter `{0}' is declared as type `{1}' but should be `{2}'",
							i+1,
							TypeManager.CSharpName (amp.ParameterType (i)),
							TypeManager.CSharpName (invoke_pd.ParameterType (i)));
						Error_ParameterMismatch (delegate_type);
						return null;
					}
				}
			}

			//
			// If we are only probing, return ourselves
			//
			if (probe)
				return this;
			
			//
			// Second: the return type of the delegate must be compatible with 
			// the anonymous type.   Instead of doing a pass to examine the block
			// we satisfy the rule by setting the return type on the EmitContext
			// to be the delegate type return type.
			//

			//MethodBuilder builder = method_data.MethodBuilder;
			//ILGenerator ig = builder.GetILGenerator ();

			
			aec = new EmitContext (
				ec.TypeContainer, ec.DeclSpace, loc, null,
				invoke_mb.ReturnType,
				/* REVIEW */ (ec.InIterator ? Modifiers.METHOD_YIELDS : 0) |
				(ec.InUnsafe ? Modifiers.UNSAFE : 0) |
				(ec.IsStatic ? Modifiers.STATIC : 0),
				/* No constructor */ false);

			aec.CurrentAnonymousMethod = this;
			ContainerAnonymousMethod = ec.CurrentAnonymousMethod;
			ContainingBlock = ec.CurrentBlock;

			if (aec.ResolveTopBlock (ec, Block, amp, null, out unreachable))
				return new AnonymousDelegate (this, delegate_type, loc).Resolve (ec);

			return null;
		}

		public override string ExprClassName {
			get {
				return "anonymous method";
			}
		}

		public MethodBuilder GetMethodBuilder ()
		{
			return method.MethodData.MethodBuilder;
		}

		public override string GetSignatureForError ()
		{
			string s = TypeManager.CSharpSignature (invoke_mb);
			return s.Substring (0, s.IndexOf (".Invoke("));
		}
		
		public bool EmitMethod (EmitContext ec)
		{
			if (!CreateMethodHost (ec))
				return false;

			MethodBuilder builder = GetMethodBuilder ();
			ILGenerator ig = builder.GetILGenerator ();
			aec.ig = ig;
			
			Parameters.LabelParameters (aec, builder);

			//
			// Adjust based on the computed state of the
			// method from CreateMethodHost
			
			aec.MethodIsStatic = (method_modifiers & Modifiers.STATIC) != 0;
			
			aec.EmitMeta (Block, amp);
			aec.EmitResolvedTopBlock (Block, unreachable);
			return true;
		}

		public override void CreateScopeType (EmitContext ec, ScopeInfo scope)
		{
			TypeBuilder container = ec.TypeContainer.TypeBuilder;
			string name = String.Format ("<>AnonHelp<{0}>", scope.id);

			scope.ScopeTypeBuilder = container.DefineNestedType (
				name, TypeAttributes.AutoLayout | TypeAttributes.Class |
				TypeAttributes.NestedAssembly, TypeManager.object_type, null);

			Type [] constructor_types = TypeManager.NoTypes;
			Parameters constructor_parameters = Parameters.EmptyReadOnlyParameters;
			scope.ScopeConstructor = scope.ScopeTypeBuilder.DefineConstructor (
				MethodAttributes.Public | MethodAttributes.HideBySig |
				MethodAttributes.SpecialName | MethodAttributes.RTSpecialName,
				CallingConventions.HasThis, constructor_types);
			InternalParameters parameter_info = new InternalParameters (constructor_types, constructor_parameters);
			TypeManager.RegisterMethod (scope.ScopeConstructor, parameter_info, constructor_types);

			ILGenerator cig = scope.ScopeConstructor.GetILGenerator ();
			cig.Emit (OpCodes.Ldarg_0);
			cig.Emit (OpCodes.Call, TypeManager.object_ctor);
			cig.Emit (OpCodes.Ret);
		}

		public static void Error_AddressOfCapturedVar (string name, Location loc)
		{
			Report.Error (1686, loc,
				"Local variable `{0}' or its members cannot have their address taken and be used inside an anonymous method block",
				name);
		}
	}

	//
	// This will emit the code for the delegate, as well delegate creation on the host
	//
	public class AnonymousDelegate : DelegateCreation {
		AnonymousMethod am;

		public AnonymousDelegate (AnonymousMethod am, Type target_type, Location l)
		{
			type = target_type;
			loc = l;
			this.am = am;
		}

		public override Expression DoResolve (EmitContext ec)
		{
			eclass = ExprClass.Value;

			return this;
		}
		
		public override void Emit (EmitContext ec)
		{
			if (!am.EmitMethod (ec))
				return;

			//
			// Now emit the delegate creation.
			//
			if ((am.method.ModFlags & Modifiers.STATIC) == 0)
				delegate_instance_expression = new AnonymousInstance (am);
			
			Expression ml = Expression.MemberLookup (ec, type, ".ctor", loc);
			constructor_method = ((MethodGroupExpr) ml).Methods [0];
			delegate_method = am.GetMethodBuilder ();
			base.Emit (ec);
		}

		class AnonymousInstance : Expression {
			AnonymousMethod am;
			
			public AnonymousInstance (AnonymousMethod am)
			{
				this.am = am;
				eclass = ExprClass.Value;
			}

			public override Expression DoResolve (EmitContext ec)
			{
				return this;