aspnetcore/src/Microsoft.AspNet.Hosting/Internal/FastHttpRequestIdentifierFe...

61 lines
2.4 KiB
C#

// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
using System;
using System.Threading;
using Microsoft.AspNet.Http.Features;
namespace Microsoft.AspNet.Hosting.Internal
{
public class FastHttpRequestIdentifierFeature : IHttpRequestIdentifierFeature
{
private static readonly string _hexChars = "0123456789ABCDEF";
// Seed the _requestId for this application instance with a random int
private static long _requestId = new Random().Next();
private string _id = null;
public string TraceIdentifier
{
get
{
// Don't incur the cost of generating the request ID until it's asked for
if (_id == null)
{
_id = GenerateRequestId(Interlocked.Increment(ref _requestId));
}
return _id;
}
set
{
_id = value;
}
}
private static string GenerateRequestId(long id)
{
// The following routine is ~33% faster than calling long.ToString() when testing in tight loops of
// 1 million iterations.
var charBuffer = new char[sizeof(long) * 2];
charBuffer[0] = _hexChars[(int)(id >> 60) & 0x0f];
charBuffer[1] = _hexChars[(int)(id >> 56) & 0x0f];
charBuffer[2] = _hexChars[(int)(id >> 52) & 0x0f];
charBuffer[3] = _hexChars[(int)(id >> 48) & 0x0f];
charBuffer[4] = _hexChars[(int)(id >> 44) & 0x0f];
charBuffer[5] = _hexChars[(int)(id >> 40) & 0x0f];
charBuffer[6] = _hexChars[(int)(id >> 36) & 0x0f];
charBuffer[7] = _hexChars[(int)(id >> 32) & 0x0f];
charBuffer[8] = _hexChars[(int)(id >> 28) & 0x0f];
charBuffer[9] = _hexChars[(int)(id >> 24) & 0x0f];
charBuffer[10] = _hexChars[(int)(id >> 20) & 0x0f];
charBuffer[11] = _hexChars[(int)(id >> 16) & 0x0f];
charBuffer[12] = _hexChars[(int)(id >> 12) & 0x0f];
charBuffer[13] = _hexChars[(int)(id >> 8) & 0x0f];
charBuffer[14] = _hexChars[(int)(id >> 4) & 0x0f];
charBuffer[15] = _hexChars[(int)(id >> 0) & 0x0f];
return new string(charBuffer);
}
}
}