linux-packaging-mono/mcs/class/Microsoft.CSharp/Microsoft.CSharp.RuntimeBinder/CSharpBinder.cs

//
// CSharpBinder.cs
//
// Authors:
//	Marek Safar  <marek.safar@gmail.com>
//
// Copyright (C) 2009 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

using System;
using System.Dynamic;
using System.Linq.Expressions;
using Compiler = Mono.CSharp;
using System.Reflection;
using System.Collections.Generic;

namespace Microsoft.CSharp.RuntimeBinder
{
	class CSharpBinder
	{
		static ConstructorInfo binder_exception_ctor;
		static object resolver = new object ();

		DynamicMetaObjectBinder binder;
		Compiler.Expression expr;
		BindingRestrictions restrictions;
		DynamicMetaObject errorSuggestion;

		public CSharpBinder (DynamicMetaObjectBinder binder, Compiler.Expression expr, DynamicMetaObject errorSuggestion)
		{
			this.binder = binder;
			this.expr = expr;
			this.restrictions = BindingRestrictions.Empty;
			this.errorSuggestion = errorSuggestion;
		}

		public Compiler.ResolveContext.Options ResolveOptions { get; set; }

		public void AddRestrictions (DynamicMetaObject arg)
		{
			restrictions = restrictions.Merge (CreateRestrictionsOnTarget (arg));
		}

		public void AddRestrictions (DynamicMetaObject[] args)
		{
			restrictions = restrictions.Merge (CreateRestrictionsOnTarget (args));
		}

		public DynamicMetaObject Bind (DynamicContext ctx, Type callingType)
		{
			Expression res;
			try {
				var rc = new Compiler.ResolveContext (new RuntimeBinderContext (ctx, callingType), ResolveOptions);

				// Static typemanager and internal caches are not thread-safe
				lock (resolver) {
					expr = expr.Resolve (rc, Compiler.ResolveFlags.VariableOrValue);
				}

				if (expr == null)
					throw new RuntimeBinderInternalCompilerException ("Expression resolved to null");

				res = expr.MakeExpression (new Compiler.BuilderContext ());
			} catch (RuntimeBinderException e) {
				if (errorSuggestion != null)
					return errorSuggestion;

				res = CreateBinderException (e.Message);
			} catch (Exception) {
				if (errorSuggestion != null)
					return errorSuggestion;

				throw;
			}

			return new DynamicMetaObject (res, restrictions);
		}

		Expression CreateBinderException (string message)
		{
			if (binder_exception_ctor == null)
				binder_exception_ctor = typeof (RuntimeBinderException).GetConstructor (new[] { typeof (string) });

			//
			// Uses target type to keep expressions composition working
			//
			return Expression.Throw (Expression.New (binder_exception_ctor, Expression.Constant (message)), binder.ReturnType);
		}

		static BindingRestrictions CreateRestrictionsOnTarget (DynamicMetaObject arg)
		{
			return arg.HasValue && arg.Value == null ?
				BindingRestrictions.GetInstanceRestriction (arg.Expression, null) :
				BindingRestrictions.GetTypeRestriction (arg.Expression, arg.LimitType);
		}

		public static BindingRestrictions CreateRestrictionsOnTarget (DynamicMetaObject[] args)
		{
			if (args.Length == 0)
				return BindingRestrictions.Empty;

			var res = CreateRestrictionsOnTarget (args[0]);
			for (int i = 1; i < args.Length; ++i)
				res = res.Merge (CreateRestrictionsOnTarget (args[i]));

			return res;
		}
	}
}