/IronPython_Main/Languages/IronPython/IronPython/Runtime/Types/ReflectedIndexer.cs

/* ****************************************************************************

 *

 * Copyright (c) Microsoft Corporation. 

 *

 * This source code is subject to terms and conditions of the Apache License, Version 2.0. A 

 * copy of the license can be found in the License.html file at the root of this distribution. If 

 * you cannot locate the  Apache License, Version 2.0, please send an email to 

 * dlr@microsoft.com. By using this source code in any fashion, you are agreeing to be bound 

 * by the terms of the Apache License, Version 2.0.

 *

 * You must not remove this notice, or any other, from this software.

 *

 *

 * ***************************************************************************/



using System;

using System.Diagnostics;

using System.Reflection;

using System.Runtime.CompilerServices;

using IronPython.Runtime.Operations;

using Microsoft.Scripting;

using Microsoft.Scripting.Generation;

using Microsoft.Scripting.Runtime;

using Microsoft.Scripting.Utils;



namespace IronPython.Runtime.Types {

    /// <summary>

    /// Provides access to non-default .NET indexers (aka properties w/ parameters).

    /// 

    /// C# doesn't support these, but both COM and VB.NET do.  The types dictionary

    /// gets populated w/a ReflectedGetterSetter indexer which is a descriptor.  Getting

    /// the descriptor returns a bound indexer.  The bound indexer supports indexing.

    /// We support multiple indexer parameters via expandable tuples.

    /// </summary>

    [PythonType("indexer#")]

    public sealed class ReflectedIndexer : ReflectedGetterSetter {

        private readonly object _instance;

        private readonly PropertyInfo/*!*/ _info;



        public ReflectedIndexer(PropertyInfo/*!*/ info, NameType nt, bool privateBinding)

            : base(new MethodInfo[] { info.GetGetMethod(privateBinding) }, new MethodInfo[] { info.GetSetMethod(privateBinding) }, nt) {

            Debug.Assert(info != null);

            

            _info = info;

        }



        public ReflectedIndexer(ReflectedIndexer from, object instance)

            : base(from) {

            _instance = instance;

            _info = from._info;

        }



        internal override bool TryGetValue(CodeContext context, object instance, PythonType owner, out object value) {

            value = new ReflectedIndexer(this, instance);

            return true;

        }



        internal override bool GetAlwaysSucceeds {

            get {

                return true;

            }

        }



        internal override Type DeclaringType {

            get { return _info.DeclaringType; }

        }



        public override PythonType PropertyType {

            [PythonHidden]

            get {

                return DynamicHelpers.GetPythonTypeFromType(_info.PropertyType);

            }

        }



        public override string __name__ {

            get { return _info.Name; }

        }



        #region Public APIs



        public bool SetValue(CodeContext context, SiteLocalStorage<CallSite<Func<CallSite, CodeContext, object, object[], object>>> storage, object[] keys, object value) {

            return CallSetter(context, storage, _instance, keys, value);

        }



        public object GetValue(CodeContext context, SiteLocalStorage<CallSite<Func<CallSite, CodeContext, object, object[], object>>> storage, object[] keys) {

            return CallGetter(context, storage, _instance, keys);

        }



        public new object __get__(CodeContext context, object instance, object owner) {

            object val;

            TryGetValue(context, instance, owner as PythonType, out val);

            return val;

        }



        public object this[SiteLocalStorage<CallSite<Func<CallSite, CodeContext, object, object[], object>>> storage, params object[] key] {

            get {

                return GetValue(DefaultContext.Default, storage, key);

            }

            set {

                if (!SetValue(DefaultContext.Default, storage, key, value)) {

                    throw PythonOps.AttributeErrorForReadonlyAttribute(DeclaringType.Name, __name__);

                }

            }

        }



        #endregion

    }



}