/src/Boo.Lang/Runtime/MethodDispatcherFactory.cs

#region license
// Copyright (c) 2004, 2007 Rodrigo B. de Oliveira (rbo@acm.org)
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
//	 * Redistributions of source code must retain the above copyright notice,
//	 this list of conditions and the following disclaimer.
//	 * Redistributions in binary form must reproduce the above copyright notice,
//	 this list of conditions and the following disclaimer in the documentation
//	 and/or other materials provided with the distribution.
//	 * Neither the name of Rodrigo B. de Oliveira nor the names of its
//	 contributors may be used to endorse or promote products derived from this
//	 software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
// THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#endregion

using System;
using System.Reflection;
using System.Collections.Generic;

namespace Boo.Lang.Runtime
{
	public class MethodDispatcherFactory : AbstractDispatcherFactory
	{
		public MethodDispatcherFactory(ExtensionRegistry extensions, object target, Type type, string methodName, params object[] arguments) : base(extensions, target, type, methodName, arguments)
		{
		}

		public Dispatcher Create()
		{
			Type[] types = GetArgumentTypes();
			CandidateMethod found = ResolveMethod(types);
			if (null != found) return EmitMethodDispatcher(found, types);
			return ProduceExtensionDispatcher();
		}

		private Dispatcher ProduceExtensionDispatcher()
		{
			CandidateMethod found = ResolveExtensionMethod();
			if (found == null) throw new System.MissingMethodException(_type.FullName, _name);
			return EmitExtensionDispatcher(found);
		}

		private CandidateMethod ResolveExtensionMethod()
		{
			return ResolveExtension(GetExtensionMethods());
		}

		private CandidateMethod ResolveMethod(Type[] argumentTypes)
		{
			return ResolveMethod(argumentTypes, GetCandidates());
		}

		private IEnumerable<MethodInfo> GetCandidates()
		{
			foreach (MethodInfo method in _type.GetMethods(RuntimeServices.DefaultBindingFlags))
			{
				if (_name != method.Name) continue;
				yield return method;
			}
		}

		private Dispatcher EmitMethodDispatcher(CandidateMethod found, Type[] argumentTypes)
		{
			return new MethodDispatcherEmitter(_type, found, argumentTypes).Emit();
		}
	}
}