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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;
using System.Threading.Tasks;
//
// XmlDownloadManager
//
internal partial class XmlDownloadManager {
[ResourceConsumption(ResourceScope.Machine)]
[ResourceExposure(ResourceScope.Machine)]
internal Task<Stream> GetStreamAsync(Uri uri, ICredentials credentials, IWebProxy proxy,
RequestCachePolicy cachePolicy) {
if (uri.Scheme == "file") {
return Task.Run<Stream>(() => { return new FileStream(uri.LocalPath, FileMode.Open, FileAccess.Read, FileShare.Read, 1, true); });
}
else {
return GetNonFileStreamAsync(uri, credentials, proxy, cachePolicy);
}
}
private async Task<Stream> GetNonFileStreamAsync(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 = await Task<WebResponse>.Factory.FromAsync(req.BeginGetResponse, req.EndGetResponse, null).ConfigureAwait(false);
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();
}
}
}
}
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