ExpandoClass.cs :  » Script » IronRuby » System » Dynamic » C# / CSharp Open Source

Home
C# / CSharp Open Source
1.2.6.4 mono .net core
2.2.6.4 mono core
3.Aspect Oriented Frameworks
4.Bloggers
5.Build Systems
6.Business Application
7.Charting Reporting Tools
8.Chat Servers
9.Code Coverage Tools
10.Content Management Systems CMS
11.CRM ERP
12.Database
13.Development
14.Email
15.Forum
16.Game
17.GIS
18.GUI
19.IDEs
20.Installers Generators
21.Inversion of Control Dependency Injection
22.Issue Tracking
23.Logging Tools
24.Message
25.Mobile
26.Network Clients
27.Network Servers
28.Office
29.PDF
30.Persistence Frameworks
31.Portals
32.Profilers
33.Project Management
34.RSS RDF
35.Rule Engines
36.Script
37.Search Engines
38.Sound Audio
39.Source Control
40.SQL Clients
41.Template Engines
42.Testing
43.UML
44.Web Frameworks
45.Web Service
46.Web Testing
47.Wiki Engines
48.Windows Presentation Foundation
49.Workflows
50.XML Parsers
C# / C Sharp
C# / C Sharp by API
C# / CSharp Tutorial
C# / CSharp Open Source » Script » IronRuby 
IronRuby » System » Dynamic » ExpandoClass.cs
/* ****************************************************************************
 *
 * Copyright (c) Microsoft Corporation. 
 *
 * This source code is subject to terms and conditions of the Microsoft Public License. A 
 * copy of the license can be found in the License.html file at the root of this distribution. If 
 * you cannot locate the  Microsoft Public License, 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 Microsoft Public License.
 *
 * You must not remove this notice, or any other, from this software.
 *
 *
 * ***************************************************************************/

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Dynamic.Utils;
using System.Text;

namespace System.Dynamic{
    /// <summary>
    /// Represents a dynamically assigned class.  Expando objects which share the same 
    /// members will share the same class.  Classes are dynamically assigned as the
    /// expando object gains members.
    /// </summary>
    internal class ExpandoClass {
        private readonly string[] _keys;                            // list of names associated with each element in the data array, sorted
        private readonly int _hashCode;                             // pre-calculated hash code of all the keys the class contains
        private Dictionary<int, List<WeakReference>> _transitions;  // cached transitions

        private const int EmptyHashCode = 6551;                     // hash code of the empty ExpandoClass.

        internal static ExpandoClass Empty = new ExpandoClass();    // The empty Expando class - all Expando objects start off w/ this class.
        
        /// <summary>
        /// Constructs the empty ExpandoClass.  This is the class used when an
        /// empty Expando object is initially constructed.
        /// </summary>
        internal ExpandoClass() {
            _hashCode = EmptyHashCode;
            _keys = new string[0];
        }

        /// <summary>
        /// Constructs a new ExpandoClass that can hold onto the specified keys.  The
        /// keys must be sorted ordinally.  The hash code must be precalculated for 
        /// the keys.
        /// </summary>
        internal ExpandoClass(string[] keys, int hashCode) {
            _hashCode = hashCode;
            _keys = keys;
        }

        /// <summary>
        /// Finds or creates a new ExpandoClass given the existing set of keys
        /// in this ExpandoClass plus the new key to be added. Members in an
        /// ExpandoClass are always stored case sensitively.
        /// </summary>
        internal ExpandoClass FindNewClass(string newKey) {
            // just XOR the newKey hash code 
            int hashCode = _hashCode ^ newKey.GetHashCode();

            lock (this) {
                List<WeakReference> infos = GetTransitionList(hashCode);

                for (int i = 0; i < infos.Count; i++) {
                    ExpandoClass klass = infos[i].Target as ExpandoClass;
                    if (klass == null) {
                        infos.RemoveAt(i);
                        i--;
                        continue;
                    }

                    if (string.Equals(klass._keys[klass._keys.Length - 1], newKey, StringComparison.Ordinal)) {
                        // the new key is the key we added in this transition
                        return klass;
                    }
                }

                // no applicable transition, create a new one
                string[] keys = new string[_keys.Length + 1];
                Array.Copy(_keys, keys, _keys.Length);
                keys[_keys.Length] = newKey;
                ExpandoClass ec = new ExpandoClass(keys, hashCode);

                infos.Add(new WeakReference(ec));
                return ec;
            }
        }

        /// <summary>
        /// Gets the lists of transitions that are valid from this ExpandoClass
        /// to an ExpandoClass whos keys hash to the apporopriate hash code.
        /// </summary>
        private List<WeakReference> GetTransitionList(int hashCode) {
            if (_transitions == null) {
                _transitions = new Dictionary<int, List<WeakReference>>();
            }

            List<WeakReference> infos;
            if (!_transitions.TryGetValue(hashCode, out infos)) {
                _transitions[hashCode] = infos = new List<WeakReference>();
            }

            return infos;
        }

        /// <summary>
        /// Gets the index at which the value should be stored for the specified name.
        /// </summary>
        internal int GetValueIndex(string name, bool caseInsensitive, ExpandoObject obj) {
            if (caseInsensitive) {
                return GetValueIndexCaseInsensitive(name, obj);
            } else {
                return GetValueIndexCaseSensitive(name);
            }
        }

        /// <summary>
        /// Gets the index at which the value should be stored for the specified name
        /// case sensitively. Returns the index even if the member is marked as deleted.
        /// </summary>
        internal int GetValueIndexCaseSensitive(string name) {
            for (int i = 0; i < _keys.Length; i++) {
                if (string.Equals(
                    _keys[i],
                    name,
                    StringComparison.Ordinal)) {
                    return i;
                }
            }
            return ExpandoObject.NoMatch;
        }

        /// <summary>
        /// Gets the index at which the value should be stored for the specified name,
        /// the method is only used in the case-insensitive case.
        /// </summary>
        /// <param name="name">the name of the member</param>
        /// <param name="obj">The ExpandoObject associated with the class
        /// that is used to check if a member has been deleted.</param>
        /// <returns>
        /// the exact match if there is one
        /// if there is exactly one member with case insensitive match, return it
        /// otherwise we throw AmbiguousMatchException.
        /// </returns>
        private int GetValueIndexCaseInsensitive(string name, ExpandoObject obj) {
            int caseInsensitiveMatch = ExpandoObject.NoMatch; //the location of the case-insensitive matching member
            lock (obj.LockObject) {
                for (int i = _keys.Length - 1; i >= 0; i--) {
                    if (string.Equals(
                        _keys[i],
                        name,
                        StringComparison.OrdinalIgnoreCase)) {
                        //if the matching member is deleted, continue searching
                        if (!obj.IsDeletedMember(i)) {
                            if (caseInsensitiveMatch == ExpandoObject.NoMatch) {
                                caseInsensitiveMatch = i;
                            } else {
                                //Ambigous match, stop searching
                                return ExpandoObject.AmbiguousMatchFound;
                            }
                        }
                    }
                }
            }
            //There is exactly one member with case insensitive match.
            return caseInsensitiveMatch;
        }

        /// <summary>
        /// Gets the names of the keys that can be stored in the Expando class.  The
        /// list is sorted ordinally.
        /// </summary>
        internal string[] Keys {
            get {
                return _keys;
            }
        }
    }
}
www.java2v.com | Contact Us
Copyright 2009 - 12 Demo Source and Support. All rights reserved.
All other trademarks are property of their respective owners.