updateconfighost.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Configuration / System / Configuration / updateconfighost.cs / 1305376 / updateconfighost.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.Configuration { 
    using System.Collections.Specialized; 
    using System.Configuration.Internal;
    using System.IO; 

    //
    // Configuration host that intercepts calls to filename functions
    // to support SaveAs to an alternate file stream. 
    //
    internal class UpdateConfigHost : DelegatingConfigHost { 
        private HybridDictionary    _streams;       // oldStreamname -> StreamUpdate 

        internal UpdateConfigHost(IInternalConfigHost host) { 
            // Delegate to the host provided.
            Host = host;
        }
 
        // Add a stream to the list of streams to intercept.
        // 
        // Parameters: 
        //  alwaysIntercept -   If true, then don't check whether the old stream and the new stream are the same.
        //                      SaveAs() will set this to true if oldStreamname is actually referring to a stream 
        //                      on a remote machine.
        internal void AddStreamname(string oldStreamname, string newStreamname, bool alwaysIntercept) {
            //
 

 
 

 
            Debug.Assert(!String.IsNullOrEmpty(oldStreamname));

            if (String.IsNullOrEmpty(oldStreamname)) {
                return; 
            }
 
            if (!alwaysIntercept && StringUtil.EqualsIgnoreCase(oldStreamname, newStreamname)) { 
                return;
            } 

            if (_streams == null) {
                _streams = new HybridDictionary(true);
            } 

            _streams[oldStreamname] = new StreamUpdate(newStreamname); 
        } 

        // Get the new stream name for a stream if a new name exists, otherwise 
        // return the original stream name.
        internal string GetNewStreamname(string oldStreamname) {
            StreamUpdate streamUpdate = GetStreamUpdate(oldStreamname, false);
            if (streamUpdate != null) { 
                return streamUpdate.NewStreamname;
            } 
 
            return oldStreamname;
        } 

        //
        // Get the StreamUpdate for a stream.
        // If alwaysIntercept is true, then the StreamUpdate is 
        // always returned if it exists.
        // If alwaysIntercept is false, then only return the StreamUpdate 
        // if the new stream has been successfully written to. 
        //
        private StreamUpdate GetStreamUpdate(string oldStreamname, bool alwaysIntercept) { 
            if (_streams == null)
                return null;

            StreamUpdate streamUpdate = (StreamUpdate) _streams[oldStreamname]; 
            if (streamUpdate != null && !alwaysIntercept && !streamUpdate.WriteCompleted) {
                streamUpdate = null; 
            } 

            return streamUpdate; 
        }

        public override object GetStreamVersion(string streamName) {
            StreamUpdate streamUpdate = GetStreamUpdate(streamName, false); 
            if (streamUpdate != null) {
                return InternalConfigHost.StaticGetStreamVersion(streamUpdate.NewStreamname); 
            } 
            else {
                return Host.GetStreamVersion(streamName); 
            }
        }

        public override Stream OpenStreamForRead(string streamName) { 
            StreamUpdate streamUpdate = GetStreamUpdate(streamName, false);
            if (streamUpdate != null) { 
                return InternalConfigHost.StaticOpenStreamForRead(streamUpdate.NewStreamname); 
            }
            else { 
                return Host.OpenStreamForRead(streamName);
            }
        }
 
        public override Stream OpenStreamForWrite(string streamName, string templateStreamName, ref object writeContext) {
            // Always attempt to write to the new stream name if it exists. 
            StreamUpdate streamUpdate = GetStreamUpdate(streamName, true); 
            if (streamUpdate != null) {
                return InternalConfigHost.StaticOpenStreamForWrite(streamUpdate.NewStreamname, templateStreamName, ref writeContext, false); 
            }
            else {
                return Host.OpenStreamForWrite(streamName, templateStreamName, ref writeContext);
            } 
        }
 
        public override void WriteCompleted(string streamName, bool success, object writeContext) { 
            StreamUpdate streamUpdate = GetStreamUpdate(streamName, true);
            if (streamUpdate != null) { 
                InternalConfigHost.StaticWriteCompleted(streamUpdate.NewStreamname, success, writeContext, false);
                //
                // Mark the write as having successfully completed, so that subsequent calls
                // to Read() will use the new stream name. 
                //
                if (success) { 
                    streamUpdate.WriteCompleted = true; 
                }
            } 
            else {
                Host.WriteCompleted(streamName, success, writeContext);
            }
        } 

        public override bool IsConfigRecordRequired(string configPath) { 
            return true; 
        }
 
        public override void DeleteStream(string streamName) {
            StreamUpdate streamUpdate = GetStreamUpdate(streamName, false);
            if (streamUpdate != null) {
                InternalConfigHost.StaticDeleteStream(streamUpdate.NewStreamname); 
            }
            else { 
                Host.DeleteStream(streamName); 
            }
        } 

        public override bool IsFile(string streamName) {
            StreamUpdate streamUpdate = GetStreamUpdate(streamName, false);
            if (streamUpdate != null) { 
                return InternalConfigHost.StaticIsFile(streamUpdate.NewStreamname);
            } 
            else { 
                return Host.IsFile(streamName);
            } 
        }
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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updateconfighost.cs source code in C# .NET

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