/Python/Product/IronPython/Interpreter/IronPythonParameterInfo.cs

// Python Tools for Visual Studio
// Copyright(c) Microsoft Corporation
// All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the License); you may not use
// this file except in compliance with the License. You may obtain a copy of the
// License at http://www.apache.org/licenses/LICENSE-2.0
//
// THIS CODE IS PROVIDED ON AN  *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS
// OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY
// IMPLIED WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
// MERCHANTABLITY OR NON-INFRINGEMENT.
//
// See the Apache Version 2.0 License for specific language governing
// permissions and limitations under the License.

using System;
using System.Collections.Generic;
using System.Reflection;
using IronPython.Runtime;
using IronPython.Runtime.Operations;
using Microsoft.PythonTools.Interpreter;
using Microsoft.Scripting;
using Microsoft.Scripting.Generation;

namespace Microsoft.IronPythonTools.Interpreter {
    class IronPythonParameterInfo : IParameterInfo {
        private readonly IronPythonInterpreter _interpreter;
        private RemoteInterpreterProxy _remote;
        private readonly ObjectIdentityHandle _parameterInfo;
        private string _name;
        private ParameterKind _paramKind;
        private IPythonType[] _paramType;
        private string _defaultValue;
        private static readonly string _noDefaultValue = "<No Default Value>";  // sentinel value to mark when an object doesn't have a default value

        public IronPythonParameterInfo(IronPythonInterpreter interpreter, ObjectIdentityHandle parameterInfo) {
            _interpreter = interpreter;
            _interpreter.UnloadingDomain += Interpreter_UnloadingDomain;
            _remote = _interpreter.Remote;
            _parameterInfo = parameterInfo;
        }

        private void Interpreter_UnloadingDomain(object sender, EventArgs e) {
            _remote = null;
            _interpreter.UnloadingDomain -= Interpreter_UnloadingDomain;
        }

        #region IParameterInfo Members

        public IList<IPythonType> ParameterTypes {
            get {
                if (_paramType == null) {
                    var ri = _remote;
                    if (ri != null) {
                        _paramType = new[] { _interpreter.GetTypeFromType(ri.GetParameterPythonType(_parameterInfo)) };
                    }
                }
                return _paramType;
            }
        }

        // FIXME
        public string Documentation {
            get { return ""; }
        }

        public string Name {
            get {
                if (_name == null) {
                    var ri = _remote;
                    _name = ri != null ? ri.GetParameterName(_parameterInfo) : string.Empty;
                }
                return _name;
            }
        }

        public bool IsParamArray {
            get {
                if (_paramKind == ParameterKind.Unknown) {
                    var ri = _remote;
                    _paramKind = ri != null ? ri.GetParameterKind(_parameterInfo) : ParameterKind.Unknown;
                }
                return _paramKind == ParameterKind.List;
            }
        }

        public bool IsKeywordDict {
            get {
                if (_paramKind == ParameterKind.Unknown) {
                    var ri = _remote;
                    _paramKind = ri != null ? ri.GetParameterKind(_parameterInfo) : ParameterKind.Unknown;
                }
                return _paramKind == ParameterKind.Dictionary;
            }
        }

        public string DefaultValue {
            get {
                if (_defaultValue == null) {
                    var ri = _remote;
                    _defaultValue = (ri != null ? ri.GetParameterDefaultValue(_parameterInfo) : null) ?? _noDefaultValue;
                }

                if (Object.ReferenceEquals(_defaultValue, _noDefaultValue)) {
                    return null;
                }

                return _noDefaultValue;
            }
        }


        #endregion
    }
}