SurrogateSelector.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / clr / src / BCL / System / Runtime / Serialization / SurrogateSelector.cs / 1305376 / SurrogateSelector.cs
                        
                        
                            using System.Diagnostics.Contracts; 
// ==++==
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// ==--==
/*============================================================ 
** 
** Class: SurrogateSelector
** 
**
** Purpose: A user-supplied class for doing the type to surrogate
**          mapping.
** 
**
===========================================================*/ 
namespace System.Runtime.Serialization { 

    using System.Runtime.Remoting; 
    using System;
    using System.Collections;
    using System.Security.Permissions;
[System.Runtime.InteropServices.ComVisible(true)] 
    public class SurrogateSelector : ISurrogateSelector {
 
        internal SurrogateHashtable m_surrogates; 
        internal ISurrogateSelector m_nextSelector;
 
        public SurrogateSelector() {
            m_surrogates = new SurrogateHashtable(32);
        }
 
        // Adds a surrogate to the list of surrogates checked.
        public virtual void AddSurrogate(Type type, StreamingContext context, ISerializationSurrogate surrogate) { 
            if (type==null) { 
                throw new ArgumentNullException("type");
            } 
            if (surrogate==null) {
                throw new ArgumentNullException("surrogate");
            }
            Contract.EndContractBlock(); 

            SurrogateKey key = new SurrogateKey(type, context); 
            m_surrogates.Add(key, surrogate);  // Hashtable does duplicate checking. 
        }
 
        [System.Security.SecurityCritical]  // auto-generated
        private static bool HasCycle(ISurrogateSelector selector) {
            ISurrogateSelector head;
            ISurrogateSelector tail; 

            Contract.Assert(selector!=null, "[HasCycle]selector!=null"); 
 

            head = selector; 
            tail = selector;

            while (head!=null) {
                head = head.GetNextSelector(); 
                if (head==null) {
                    return true; 
                } 
                if (head==tail) {
                    return false; 
                }
                head = head.GetNextSelector();
                tail = tail.GetNextSelector();
 
                if (head==tail) {
                    return false; 
                } 
            }
 
            return true;

        }
 
        // Adds another selector to check if we don't have  match within this selector.
        // The logic is:"Add this onto the list as the first thing that you check after yourself." 
        [System.Security.SecurityCritical]  // auto-generated_required 
        public virtual void ChainSelector(ISurrogateSelector selector) {
            ISurrogateSelector temp; 
            ISurrogateSelector tempCurr;
            ISurrogateSelector tempPrev;
            ISurrogateSelector tempEnd;
 
            if (selector==null) {
                throw new ArgumentNullException("selector"); 
            } 
            Contract.EndContractBlock();
 
            //
            // Verify that we don't try and add ourself twice.
            //
            if (selector==this) { 
                throw new SerializationException(Environment.GetResourceString("Serialization_DuplicateSelector"));
            } 
 
            //
            // Verify that the argument doesn't contain a cycle. 
            //
            if (!HasCycle(selector)) {
                throw new ArgumentException(Environment.GetResourceString("Serialization_SurrogateCycleInArgument"), "selector");
            } 

            // 
            // Check for a cycle that would lead back to this.  We find the end of the list that we're being asked to 
            // insert for use later.
            // 
            tempCurr = selector.GetNextSelector();
            tempEnd = selector;
            while (tempCurr!=null && tempCurr!=this) {
                tempEnd = tempCurr; 
                tempCurr = tempCurr.GetNextSelector();
            } 
            if (tempCurr==this) { 
                throw new ArgumentException(Environment.GetResourceString("Serialization_SurrogateCycle"), "selector");
            } 

            //
            // Check for a cycle later in the list which would be introduced by this insertion.
            // 
            tempCurr = selector;
            tempPrev = selector; 
            while(tempCurr!=null) { 
                if (tempCurr==tempEnd) {
                    tempCurr = this.GetNextSelector(); 
                } else {
                    tempCurr = tempCurr.GetNextSelector();
                }
                if (tempCurr==null) { 
                    break;
                } 
                if (tempCurr==tempPrev) { 
                    throw new ArgumentException(Environment.GetResourceString("Serialization_SurrogateCycle"), "selector");
                } 

                if (tempCurr==tempEnd) {
                    tempCurr = this.GetNextSelector();
                } else { 
                    tempCurr = tempCurr.GetNextSelector();
                } 
 

                if (tempPrev==tempEnd) { 
                    tempPrev = this.GetNextSelector();
                } else {
                    tempPrev = tempPrev.GetNextSelector();
                } 
                if (tempCurr==tempPrev) {
                    throw new ArgumentException(Environment.GetResourceString("Serialization_SurrogateCycle"), "selector"); 
                } 
            }
 
            //
            // Add the new selector and it's entire chain of selectors as the next thing that
            // we check.
            // 
            temp = m_nextSelector;
            m_nextSelector = selector; 
            if (temp!=null) { 
                tempEnd.ChainSelector(temp);
            } 
        }

        // Get the next selector on the chain of selectors.
        [System.Security.SecurityCritical]  // auto-generated_required 
        public virtual ISurrogateSelector GetNextSelector() {
            return m_nextSelector; 
        } 

        // Gets the surrogate for a particular type.  If this selector can't 
        // provide a surrogate, it checks with all of it's children before returning null.
        [System.Security.SecurityCritical]  // auto-generated_required
        public virtual ISerializationSurrogate GetSurrogate(Type type, StreamingContext context, out ISurrogateSelector selector) {
            if (type==null) { 
                throw new ArgumentNullException("type");
            } 
            Contract.EndContractBlock(); 

            selector = this; 

            SurrogateKey key = new SurrogateKey(type, context);
            ISerializationSurrogate temp = (ISerializationSurrogate)m_surrogates[key];
            if (temp!=null) { 
                return temp;
            } 
            if (m_nextSelector!=null) { 
                return m_nextSelector.GetSurrogate(type, context, out selector);
            } 
            return null;
        }

        // Removes the surrogate associated with a given type.  Does not 
        // check chained surrogates.
        public virtual void RemoveSurrogate(Type type, StreamingContext context) { 
            if (type==null) { 
                throw new ArgumentNullException("type");
            } 

            Contract.EndContractBlock();

            SurrogateKey key = new SurrogateKey(type, context); 
            m_surrogates.Remove(key);
        } 
    } 

    //< 

    [Serializable]
    internal class SurrogateKey {
        internal Type m_type; 
        internal StreamingContext m_context;
 
        internal SurrogateKey(Type type, StreamingContext context) { 
            m_type = type;
            m_context = context; 
        }

        public override int GetHashCode() {
            return m_type.GetHashCode(); 
        }
    } 
 
    // Subclass to override KeyEquals.
    class SurrogateHashtable : Hashtable { 
        internal SurrogateHashtable(int size):base(size){
            ;
        }
        // Must return true if the context to serialize for (givenContext) 
        // is a subset of the context for which the serialization selector is provided (presentContext)
        // Note: This is done by overriding KeyEquals rather than overriding Equals() in the SurrogateKey 
        // class because Equals() method must be commutative. 
        protected override bool KeyEquals(Object key, Object item){
            SurrogateKey givenValue = (SurrogateKey)item; 
            SurrogateKey presentValue = (SurrogateKey)key;
            return presentValue.m_type == givenValue.m_type &&
                   (presentValue.m_context.m_state & givenValue.m_context.m_state) == givenValue.m_context.m_state &&
                   presentValue.m_context.Context == givenValue.m_context.Context; 
        }
    } 
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
using System.Diagnostics.Contracts; 
// ==++==
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// ==--==
/*============================================================ 
** 
** Class: SurrogateSelector
** 
**
** Purpose: A user-supplied class for doing the type to surrogate
**          mapping.
** 
**
===========================================================*/ 
namespace System.Runtime.Serialization { 

    using System.Runtime.Remoting; 
    using System;
    using System.Collections;
    using System.Security.Permissions;
[System.Runtime.InteropServices.ComVisible(true)] 
    public class SurrogateSelector : ISurrogateSelector {
 
        internal SurrogateHashtable m_surrogates; 
        internal ISurrogateSelector m_nextSelector;
 
        public SurrogateSelector() {
            m_surrogates = new SurrogateHashtable(32);
        }
 
        // Adds a surrogate to the list of surrogates checked.
        public virtual void AddSurrogate(Type type, StreamingContext context, ISerializationSurrogate surrogate) { 
            if (type==null) { 
                throw new ArgumentNullException("type");
            } 
            if (surrogate==null) {
                throw new ArgumentNullException("surrogate");
            }
            Contract.EndContractBlock(); 

            SurrogateKey key = new SurrogateKey(type, context); 
            m_surrogates.Add(key, surrogate);  // Hashtable does duplicate checking. 
        }
 
        [System.Security.SecurityCritical]  // auto-generated
        private static bool HasCycle(ISurrogateSelector selector) {
            ISurrogateSelector head;
            ISurrogateSelector tail; 

            Contract.Assert(selector!=null, "[HasCycle]selector!=null"); 
 

            head = selector; 
            tail = selector;

            while (head!=null) {
                head = head.GetNextSelector(); 
                if (head==null) {
                    return true; 
                } 
                if (head==tail) {
                    return false; 
                }
                head = head.GetNextSelector();
                tail = tail.GetNextSelector();
 
                if (head==tail) {
                    return false; 
                } 
            }
 
            return true;

        }
 
        // Adds another selector to check if we don't have  match within this selector.
        // The logic is:"Add this onto the list as the first thing that you check after yourself." 
        [System.Security.SecurityCritical]  // auto-generated_required 
        public virtual void ChainSelector(ISurrogateSelector selector) {
            ISurrogateSelector temp; 
            ISurrogateSelector tempCurr;
            ISurrogateSelector tempPrev;
            ISurrogateSelector tempEnd;
 
            if (selector==null) {
                throw new ArgumentNullException("selector"); 
            } 
            Contract.EndContractBlock();
 
            //
            // Verify that we don't try and add ourself twice.
            //
            if (selector==this) { 
                throw new SerializationException(Environment.GetResourceString("Serialization_DuplicateSelector"));
            } 
 
            //
            // Verify that the argument doesn't contain a cycle. 
            //
            if (!HasCycle(selector)) {
                throw new ArgumentException(Environment.GetResourceString("Serialization_SurrogateCycleInArgument"), "selector");
            } 

            // 
            // Check for a cycle that would lead back to this.  We find the end of the list that we're being asked to 
            // insert for use later.
            // 
            tempCurr = selector.GetNextSelector();
            tempEnd = selector;
            while (tempCurr!=null && tempCurr!=this) {
                tempEnd = tempCurr; 
                tempCurr = tempCurr.GetNextSelector();
            } 
            if (tempCurr==this) { 
                throw new ArgumentException(Environment.GetResourceString("Serialization_SurrogateCycle"), "selector");
            } 

            //
            // Check for a cycle later in the list which would be introduced by this insertion.
            // 
            tempCurr = selector;
            tempPrev = selector; 
            while(tempCurr!=null) { 
                if (tempCurr==tempEnd) {
                    tempCurr = this.GetNextSelector(); 
                } else {
                    tempCurr = tempCurr.GetNextSelector();
                }
                if (tempCurr==null) { 
                    break;
                } 
                if (tempCurr==tempPrev) { 
                    throw new ArgumentException(Environment.GetResourceString("Serialization_SurrogateCycle"), "selector");
                } 

                if (tempCurr==tempEnd) {
                    tempCurr = this.GetNextSelector();
                } else { 
                    tempCurr = tempCurr.GetNextSelector();
                } 
 

                if (tempPrev==tempEnd) { 
                    tempPrev = this.GetNextSelector();
                } else {
                    tempPrev = tempPrev.GetNextSelector();
                } 
                if (tempCurr==tempPrev) {
                    throw new ArgumentException(Environment.GetResourceString("Serialization_SurrogateCycle"), "selector"); 
                } 
            }
 
            //
            // Add the new selector and it's entire chain of selectors as the next thing that
            // we check.
            // 
            temp = m_nextSelector;
            m_nextSelector = selector; 
            if (temp!=null) { 
                tempEnd.ChainSelector(temp);
            } 
        }

        // Get the next selector on the chain of selectors.
        [System.Security.SecurityCritical]  // auto-generated_required 
        public virtual ISurrogateSelector GetNextSelector() {
            return m_nextSelector; 
        } 

        // Gets the surrogate for a particular type.  If this selector can't 
        // provide a surrogate, it checks with all of it's children before returning null.
        [System.Security.SecurityCritical]  // auto-generated_required
        public virtual ISerializationSurrogate GetSurrogate(Type type, StreamingContext context, out ISurrogateSelector selector) {
            if (type==null) { 
                throw new ArgumentNullException("type");
            } 
            Contract.EndContractBlock(); 

            selector = this; 

            SurrogateKey key = new SurrogateKey(type, context);
            ISerializationSurrogate temp = (ISerializationSurrogate)m_surrogates[key];
            if (temp!=null) { 
                return temp;
            } 
            if (m_nextSelector!=null) { 
                return m_nextSelector.GetSurrogate(type, context, out selector);
            } 
            return null;
        }

        // Removes the surrogate associated with a given type.  Does not 
        // check chained surrogates.
        public virtual void RemoveSurrogate(Type type, StreamingContext context) { 
            if (type==null) { 
                throw new ArgumentNullException("type");
            } 

            Contract.EndContractBlock();

            SurrogateKey key = new SurrogateKey(type, context); 
            m_surrogates.Remove(key);
        } 
    } 

    //< 

    [Serializable]
    internal class SurrogateKey {
        internal Type m_type; 
        internal StreamingContext m_context;
 
        internal SurrogateKey(Type type, StreamingContext context) { 
            m_type = type;
            m_context = context; 
        }

        public override int GetHashCode() {
            return m_type.GetHashCode(); 
        }
    } 
 
    // Subclass to override KeyEquals.
    class SurrogateHashtable : Hashtable { 
        internal SurrogateHashtable(int size):base(size){
            ;
        }
        // Must return true if the context to serialize for (givenContext) 
        // is a subset of the context for which the serialization selector is provided (presentContext)
        // Note: This is done by overriding KeyEquals rather than overriding Equals() in the SurrogateKey 
        // class because Equals() method must be commutative. 
        protected override bool KeyEquals(Object key, Object item){
            SurrogateKey givenValue = (SurrogateKey)item; 
            SurrogateKey presentValue = (SurrogateKey)key;
            return presentValue.m_type == givenValue.m_type &&
                   (presentValue.m_context.m_state & givenValue.m_context.m_state) == givenValue.m_context.m_state &&
                   presentValue.m_context.Context == givenValue.m_context.Context; 
        }
    } 
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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SurrogateSelector.cs source code in C# .NET

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