MailWriter.cs source code in C# .NET

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

namespace System.Net.Mail 
{ 
    using System;
    using System.Collections; 
    using System.IO;
    using System.Text;
    using System.Collections.Specialized;
    using System.Net.Mime; 

    internal class MailWriter:BaseWriter 
    { 
        static byte[] CRLF = new byte[] { (byte)'\r', (byte)'\n' };
 
        //this is the maximum default line length that can actually be written.  When encoding
        //headers, the line length is more conservative to account for things like folding.
        //in MailWriter, all encoding has already been done so this will only fold lines
        //that are NOT encoded already, which means being less conservative is ok. 
        static int writerDefaultLineLength = 76;
 
        Stream contentStream; 
        bool isInContent;
        int lineLength; 
        EventHandler onCloseHandler;
        Stream stream;
        BufferBuilder bufferBuilder = new BufferBuilder();
 
        static AsyncCallback onWrite = new AsyncCallback(OnWrite);
 
        ///  
        /// ctor.
        ///  
        /// Underlying stream
        internal MailWriter(Stream stream) : this(stream, writerDefaultLineLength)
        {
        } 

        ///  
        /// ctor. 
        /// 
        /// Underlying stream 
        /// Preferred line length
        internal MailWriter(Stream stream, int lineLength)
        {
            if (stream == null) 
                throw new ArgumentNullException("stream");
 
            if (lineLength < 0) 
                throw new ArgumentOutOfRangeException("lineLength");
 
            this.stream = stream;
            this.lineLength = lineLength;
            this.onCloseHandler = new EventHandler(OnClose);
        } 

        ///  
        /// Closes underlying stream. 
        /// 
        internal override void Close() 
        {
            //

            this.stream.Write(CRLF,0,2); 
            this.stream.Close();
        } 
 
        internal IAsyncResult BeginGetContentStream(ContentTransferEncoding contentTransferEncoding, AsyncCallback callback, object state)
        { 
            MultiAsyncResult multiResult = new MultiAsyncResult(this, callback, state);

            Stream s = GetContentStream(contentTransferEncoding, multiResult);
 
            if (!(multiResult.Result is Exception))
                multiResult.Result = s; 
 
            multiResult.CompleteSequence();
 
            return multiResult;
        }

        internal override IAsyncResult BeginGetContentStream(AsyncCallback callback, object state) 
        {
            return BeginGetContentStream(ContentTransferEncoding.SevenBit, callback, state); 
        } 

        internal override Stream EndGetContentStream(IAsyncResult result) 
        {
            object o = MultiAsyncResult.End(result);
            if(o is Exception){
                throw (Exception) o; 
            }
            return (Stream)o; 
        } 

        internal Stream GetContentStream(ContentTransferEncoding contentTransferEncoding) 
        {
            return GetContentStream(contentTransferEncoding, null);
        }
 
        internal override Stream GetContentStream()
        { 
            return GetContentStream(ContentTransferEncoding.SevenBit); 
        }
 
        Stream GetContentStream(ContentTransferEncoding contentTransferEncoding, MultiAsyncResult multiResult)
        {
            if (this.isInContent)
                throw new InvalidOperationException(SR.GetString(SR.MailWriterIsInContent)); 

            this.isInContent = true; 
 
            this.bufferBuilder.Append(CRLF);
            Flush(multiResult); 

            Stream stream = this.stream;
            if (contentTransferEncoding == ContentTransferEncoding.SevenBit)
                stream = new SevenBitStream(stream); 
            else if (contentTransferEncoding == ContentTransferEncoding.QuotedPrintable)
                stream = new QuotedPrintableStream(stream, this.lineLength); 
            else if (contentTransferEncoding == ContentTransferEncoding.Base64) 
                stream = new Base64Stream(stream, this.lineLength);
 
            ClosableStream cs = new ClosableStream(stream, this.onCloseHandler);
            this.contentStream = cs;
            return cs;
        } 

 
        internal override void WriteHeader(string name, string value) 
        {
            if (name == null) 
                throw new ArgumentNullException("name");

            if (value == null)
                throw new ArgumentNullException("value"); 

            if (this.isInContent) 
                throw new InvalidOperationException(SR.GetString(SR.MailWriterIsInContent)); 

            this.bufferBuilder.Append(name); 
            this.bufferBuilder.Append(": ");
            WriteAndFold(value);//, name.Length + 2);
            this.bufferBuilder.Append(CRLF);
        } 

 
        internal override void WriteHeaders(NameValueCollection headers) { 
            if (headers == null)
                throw new ArgumentNullException("headers"); 

            if (this.isInContent)
                throw new InvalidOperationException(SR.GetString(SR.MailWriterIsInContent));
 
            foreach (string key in headers) {
                string[] values = headers.GetValues(key); 
                foreach (string value in values) 
                    WriteHeader(key, value);
            } 
        }

        // helper methods
 
        /// 
        /// Called when the current stream is closed.  Allows us to 
        /// prepare for the next message part. 
        /// 
        /// Sender of the close event 
        /// Event args (not used)
        void OnClose(object sender, EventArgs args)
        {
            System.Diagnostics.Debug.Assert(this.contentStream == sender); 

            this.contentStream.Flush(); 
 
            this.contentStream = null;
        } 

        static void OnWrite(IAsyncResult result)
        {
            if (!result.CompletedSynchronously) 
            {
                MultiAsyncResult multiResult = (MultiAsyncResult)result.AsyncState; 
                MailWriter thisPtr = (MailWriter)multiResult.Context; 
                try
                { 
                    thisPtr.stream.EndWrite(result);
                    multiResult.Leave();
                }
                catch (Exception e) 
                {
                    multiResult.Leave(e); 
                } 
            }
        } 

        void Flush(MultiAsyncResult multiResult)
        {
            if (this.bufferBuilder.Length > 0) 
            {
                if (multiResult != null) 
                { 
                    multiResult.Enter();
                    IAsyncResult result = this.stream.BeginWrite(this.bufferBuilder.GetBuffer(), 0, this.bufferBuilder.Length, onWrite, multiResult); 
                    if (result.CompletedSynchronously)
                    {
                        this.stream.EndWrite(result);
                        multiResult.Leave(); 
                    }
                } 
                else 
                {
                    this.stream.Write(this.bufferBuilder.GetBuffer(), 0, this.bufferBuilder.Length); 
                }
                this.bufferBuilder.Reset();
            }
        } 

 
 
        void WriteAndFold(string value) {
            //only fold if line does not contain a soft CRLF.  This is for non-byte-encoded headers and 
            //the message body
            if (value.Length < writerDefaultLineLength || value.Contains("\r\n")) {
                bufferBuilder.Append(value);
                return; 
            }
 
            int i = 0; 
            int j = value.Length;
 
            while (j - i > writerDefaultLineLength){
                int whiteSpace = value.LastIndexOf(' ', i + writerDefaultLineLength - 1, writerDefaultLineLength-1);
                if (whiteSpace > -1) {
                    bufferBuilder.Append(value, i, whiteSpace-i); 
                    bufferBuilder.Append(CRLF);
                    i = whiteSpace; 
                } 
                else {
                    bufferBuilder.Append(value, i, writerDefaultLineLength); 
                    i += writerDefaultLineLength;
                }
            }
            if (i < j){ 
                bufferBuilder.Append(value, i, j-i);
            } 
        } 
    }
} 

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

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