/IronPython_Main/Languages/IronPython/IronPython/Runtime/Types/ReflectedProperty.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.

 *

 *

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



#if !CLR2

using System.Linq.Expressions;

#else

using Microsoft.Scripting.Ast;

#endif



using System;

using System.Diagnostics;

using System.Dynamic;

using System.Reflection;

using System.Runtime.CompilerServices;



using Microsoft.Scripting;

using Microsoft.Scripting.Actions;

using Microsoft.Scripting.Generation;

using Microsoft.Scripting.Utils;



using IronPython.Runtime.Binding;

using IronPython.Runtime.Operations;



using AstUtils = Microsoft.Scripting.Ast.Utils;



namespace IronPython.Runtime.Types {

    [PythonType("getset_descriptor")]

    public class ReflectedProperty : ReflectedGetterSetter, ICodeFormattable {

        private readonly PropertyInfo/*!*/ _info;



        public ReflectedProperty(PropertyInfo info, MethodInfo getter, MethodInfo setter, NameType nt)

            : base(new MethodInfo[] { getter }, new MethodInfo[] { setter }, nt) {

            Debug.Assert(info != null);



            _info = info;

        }



        /// <summary>

        /// True if generating code for gets can result in more optimal accesses.

        /// </summary>

        internal override bool CanOptimizeGets {

            get {

                return true;

            }

        }



        public ReflectedProperty(PropertyInfo info, MethodInfo[] getters, MethodInfo[] setters, NameType nt)

            : base(getters, setters, nt) {

            Debug.Assert(info != null);



            _info = info;

        }



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

            if (Setter.Length == 0) {

                return false;

            }



            if (instance == null) {

                foreach (MethodInfo mi in Setter) {

                    if(mi.IsStatic && DeclaringType != owner.UnderlyingSystemType) {

                        return false;

                    } else if (mi.IsProtected()) {

                        throw PythonOps.TypeErrorForProtectedMember(owner.UnderlyingSystemType, _info.Name);

                    }

                }

            } else if (instance != null) {

                foreach (MethodInfo mi in Setter) {

                    if (mi.IsStatic) {

                        return false;

                    }

                }

            }



            return CallSetter(context, PythonContext.GetContext(context).GetGenericCallSiteStorage(), instance, ArrayUtils.EmptyObjects, value);

        }



        internal override Type DeclaringType {

            get { return _info.DeclaringType; }

        }



        public override string __name__ {

            get { return _info.Name; }

        }



        public PropertyInfo Info {

            [PythonHidden]

            get {

                return _info;

            }

        }



        public override PythonType PropertyType {

            [PythonHidden]

            get {

                return DynamicHelpers.GetPythonTypeFromType(_info.PropertyType);

            }

        }



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

            PerfTrack.NoteEvent(PerfTrack.Categories.Properties, this);



            value = CallGetter(context, owner, PythonContext.GetContext(context).GetGenericCallSiteStorage0(), instance);

            return true;

        }



        private object CallGetter(CodeContext context, PythonType owner, SiteLocalStorage<CallSite<Func<CallSite, CodeContext, object, object>>> storage, object instance) {

            if (NeedToReturnProperty(instance, Getter)) {

                return this;

            }



            if (Getter.Length == 0) {

                throw new MissingMemberException("unreadable property");

            }



            if (owner == null) {

                owner = DynamicHelpers.GetPythonType(instance);

            }



            // this matches the logic in the default binder when it does a property get.  We 

            // need to duplicate it here to be consistent for all gets.

            MethodInfo[] members = Getter;



            Type type = owner.UnderlyingSystemType;

            if (Getter.Length > 1) {

                // if we were given multiple members pick the member closest to the type...                

                Type bestMemberDeclaringType = Getter[0].DeclaringType;

                MethodInfo bestMember = Getter[0];



                for (int i = 1; i < Getter.Length; i++) {

                    MethodInfo mt = Getter[i];

                    if (!IsApplicableForType(type, mt)) {

                        continue;

                    }



                    if (Getter[i].DeclaringType.IsSubclassOf(bestMemberDeclaringType) ||

                        !IsApplicableForType(type, bestMember)) {

                        bestMember = Getter[i];

                        bestMemberDeclaringType = Getter[i].DeclaringType;

                    }

                }

                members = new MethodInfo[] { bestMember };

            }



            BuiltinFunction target = PythonTypeOps.GetBuiltinFunction(type, __name__, members);



            return target.Call0(context, storage, instance);

        }



        private static bool IsApplicableForType(Type type, MethodInfo mt) {

            return mt.DeclaringType == type || type.IsSubclassOf(mt.DeclaringType);

        }



        internal override bool GetAlwaysSucceeds {

            get {

                return true;

            }

        }



        internal override bool TryDeleteValue(CodeContext context, object instance, PythonType owner) {

            __delete__(instance);

            return true;

        }



        internal override void MakeGetExpression(PythonBinder/*!*/ binder, Expression/*!*/ codeContext, DynamicMetaObject instance, DynamicMetaObject/*!*/ owner, ConditionalBuilder/*!*/ builder) {

            if (Getter.Length != 0 && !Getter[0].IsPublic) {

                // fallback to runtime call

                base.MakeGetExpression(binder, codeContext, instance, owner, builder);

            } else if (NeedToReturnProperty(instance, Getter)) {

                builder.FinishCondition(AstUtils.Constant(this));

            } else if (Getter[0].ContainsGenericParameters) {

                builder.FinishCondition(

                    DefaultBinder.MakeError(

                        binder.MakeContainsGenericParametersError(

                            MemberTracker.FromMemberInfo(_info)

                        ),

                        typeof(object)

                    ).Expression

                );

            } else if (instance != null) {

                builder.FinishCondition(

                    AstUtils.Convert(

                        binder.MakeCallExpression(

                            new PythonOverloadResolverFactory(binder, codeContext),

                            Getter[0],

                            instance

                        ).Expression,

                        typeof(object)

                    )

                );

            } else {

                builder.FinishCondition(

                    AstUtils.Convert(

                        binder.MakeCallExpression(

                            new PythonOverloadResolverFactory(binder, codeContext),

                            Getter[0]

                        ).Expression,

                        typeof(object)

                    )

                );                

            }

        }



        internal override bool IsAlwaysVisible {

            get {

                return NameType == NameType.PythonProperty;

            }

        }



        internal override bool IsSetDescriptor(CodeContext context, PythonType owner) {

            return Setter.Length != 0;

        }



        #region Public Python APIs



        /// <summary>

        /// Convenience function for users to call directly

        /// </summary>

        [PythonHidden]

        public object GetValue(CodeContext context, object instance) {

            object value;

            if (TryGetValue(context, instance, DynamicHelpers.GetPythonType(instance), out value)) {

                return value;

            }

            throw new InvalidOperationException("cannot get property");

        }



        /// <summary>

        /// Convenience function for users to call directly

        /// </summary>

        [PythonHidden]

        public void SetValue(CodeContext context, object instance, object value) {

            if (!TrySetValue(context, instance, DynamicHelpers.GetPythonType(instance), value)) {

                throw new InvalidOperationException("cannot set property");

            }

        }



        public void __set__(CodeContext context, object instance, object value) {

            // TODO: Throw?  currently we have a test that verifies we never throw when this is called directly.

            TrySetValue(context, instance, DynamicHelpers.GetPythonType(instance), value);

        }



        public void __delete__(object instance) {

            if (Setter.Length != 0)

                throw PythonOps.AttributeErrorForReadonlyAttribute(

                    DynamicHelpers.GetPythonTypeFromType(DeclaringType).Name,

                    __name__);

            else

                throw PythonOps.AttributeErrorForBuiltinAttributeDeletion(

                    DynamicHelpers.GetPythonTypeFromType(DeclaringType).Name,

                    __name__);

        }



        public string __doc__ {

            get {

                return DocBuilder.DocOneInfo(Info);

            }

        }



        #endregion



        #region ICodeFormattable Members



        public string/*!*/ __repr__(CodeContext/*!*/ context) {

            return string.Format("<property# {0} on {1}>",

                __name__,

                DynamicHelpers.GetPythonTypeFromType(DeclaringType).Name);

        }



        #endregion

    }

}