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//------------------------------------------------------------------------------
// <copyright file="XmlDownloadManager.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
// <owner current="true" primary="true">[....]</owner>
//------------------------------------------------------------------------------
namespace System.Xml {
using System;
using System.IO;
using System.Security;
using System.Collections;
using System.Net;
using System.Net.Cache;
using System.Runtime.Versioning;
//
// XmlDownloadManager
//
internal partial class XmlDownloadManager {
Hashtable connections;
[ResourceConsumption(ResourceScope.Machine)]
[ResourceExposure(ResourceScope.Machine)]
internal Stream GetStream(Uri uri, ICredentials credentials, IWebProxy proxy,
RequestCachePolicy cachePolicy) {
if ( uri.Scheme == "file" ) {
return new FileStream( uri.LocalPath, FileMode.Open, FileAccess.Read, FileShare.Read, 1 );
}
else {
return GetNonFileStream( uri, credentials, proxy, cachePolicy );
}
}
private Stream GetNonFileStream( Uri uri, ICredentials credentials, IWebProxy proxy,
RequestCachePolicy cachePolicy ) {
WebRequest req = WebRequest.Create( uri );
if ( credentials != null ) {
req.Credentials = credentials;
}
if ( proxy != null ) {
req.Proxy = proxy;
}
if ( cachePolicy != null ) {
req.CachePolicy = cachePolicy;
}
WebResponse resp = req.GetResponse();
HttpWebRequest webReq = req as HttpWebRequest;
if ( webReq != null ) {
lock ( this ) {
if ( connections == null ) {
connections = new Hashtable();
}
OpenedHost openedHost = (OpenedHost)connections[webReq.Address.Host];
if ( openedHost == null ) {
openedHost = new OpenedHost();
}
if ( openedHost.nonCachedConnectionsCount < webReq.ServicePoint.ConnectionLimit - 1 ) {
// we are not close to connection limit -> don't cache the stream
if ( openedHost.nonCachedConnectionsCount == 0 ) {
connections.Add( webReq.Address.Host, openedHost );
}
openedHost.nonCachedConnectionsCount++;
return new XmlRegisteredNonCachedStream( resp.GetResponseStream(), this, webReq.Address.Host );
}
else {
// cache the stream and save the connection for the next request
return new XmlCachedStream( resp.ResponseUri, resp.GetResponseStream() );
}
}
}
else {
return resp.GetResponseStream();
}
}
internal void Remove( string host ) {
lock ( this ) {
OpenedHost openedHost = (OpenedHost)connections[host];
if ( openedHost != null ) {
if ( --openedHost.nonCachedConnectionsCount == 0 ) {
connections.Remove( host );
}
}
}
}
}
//
// OpenedHost
//
internal class OpenedHost {
internal int nonCachedConnectionsCount;
}
//
// XmlRegisteredNonCachedStream
//
internal class XmlRegisteredNonCachedStream : Stream {
protected Stream stream;
XmlDownloadManager downloadManager;
string host;
internal XmlRegisteredNonCachedStream( Stream stream, XmlDownloadManager downloadManager, string host ) {
this.stream = stream;
this.downloadManager = downloadManager;
this.host = host;
}
~XmlRegisteredNonCachedStream() {
if ( downloadManager != null ) {
downloadManager.Remove( host );
}
stream = null;
// The base class, Stream, provides its own finalizer
}
protected override void Dispose( bool disposing ) {
try {
if ( disposing && stream != null ) {
if ( downloadManager != null ) {
downloadManager.Remove( host );
}
stream.Close();
}
stream = null;
GC.SuppressFinalize( this ); // do not call finalizer
}
finally {
base.Dispose( disposing );
}
}
//
// Stream
//
public override IAsyncResult BeginRead( byte[] buffer, int offset, int count, AsyncCallback callback, object state ) {
return stream.BeginRead( buffer, offset, count, callback, state );
}
public override IAsyncResult BeginWrite( byte[] buffer, int offset, int count, AsyncCallback callback, object state ) {
return stream.BeginWrite( buffer, offset, count, callback, state );
}
public override int EndRead( IAsyncResult asyncResult ) {
return stream.EndRead( asyncResult );
}
public override void EndWrite( IAsyncResult asyncResult ) {
stream.EndWrite( asyncResult );
}
public override void Flush() {
stream.Flush();
}
public override int Read( byte[] buffer, int offset, int count ) {
return stream.Read( buffer, offset, count );
}
public override int ReadByte() {
return stream.ReadByte();
}
public override long Seek( long offset, SeekOrigin origin ) {
return stream.Seek( offset, origin );
}
public override void SetLength( long value ) {
stream.SetLength( value );
}
public override void Write( byte[] buffer, int offset, int count ) {
stream.Write( buffer, offset, count );
}
public override void WriteByte( byte value ) {
stream.WriteByte( value );
}
public override Boolean CanRead {
get { return stream.CanRead; }
}
public override Boolean CanSeek {
get { return stream.CanSeek; }
}
public override Boolean CanWrite {
get { return stream.CanWrite; }
}
public override long Length {
get { return stream.Length; }
}
public override long Position {
get { return stream.Position; }
set { stream.Position = value; }
}
}
//
// XmlCachedStream
//
internal class XmlCachedStream : MemoryStream {
private const int MoveBufferSize = 4096;
private Uri uri;
internal XmlCachedStream( Uri uri, Stream stream )
: base() {
this.uri = uri;
try {
byte[] bytes = new byte[MoveBufferSize];
int read = 0;
while ( ( read = stream.Read( bytes, 0, MoveBufferSize ) ) > 0 ) {
this.Write( bytes, 0, read );
}
base.Position = 0;
}
finally {
stream.Close();
}
}
}
}
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