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Optimize form reader allocations

This commit is contained in:
Pavel Krymets 2016-05-25 10:32:06 -07:00
parent 485e2e8327
commit c63f02c19f
4 changed files with 178 additions and 60 deletions
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147
src/Microsoft.AspNetCore.WebUtilities/FormReader.cs
View File

@ -28,6 +28,9 @@ namespace Microsoft.AspNetCore.WebUtilities
private readonly StringBuilder _builder = new StringBuilder();
private int _bufferOffset;
private int _bufferCount;
private string _currentKey;
private string _currentValue;
private bool _endOfStream;
private bool _disposed;
public FormReader(string data)
@ -97,13 +100,29 @@ namespace Microsoft.AspNetCore.WebUtilities
/// <returns>The next key value pair, or null when the end of the form is reached.</returns>
public KeyValuePair<string, string>? ReadNextPair()
{
var key = ReadWord('=', KeyLengthLimit);
if (string.IsNullOrEmpty(key) && _bufferCount == 0)
ReadNextPairImpl();
if (ReadSucceded())
{
return null;
return new KeyValuePair<string, string>(_currentKey, _currentValue);
}
return null;
}
private void ReadNextPairImpl()
{
StartReadNextPair();
while (!_endOfStream)
{
// Empty
if (_bufferCount == 0)
{
Buffer();
}
if (TryReadNextPair())
{
break;
}
}
var value = ReadWord('&', ValueLengthLimit);
return new KeyValuePair<string, string>(key, value);
}
// Format: key1=value1&key2=value2
@ -114,51 +133,74 @@ namespace Microsoft.AspNetCore.WebUtilities
/// <returns>The next key value pair, or null when the end of the form is reached.</returns>
public async Task<KeyValuePair<string, string>?> ReadNextPairAsync(CancellationToken cancellationToken = new CancellationToken())
{
var key = await ReadWordAsync('=', KeyLengthLimit, cancellationToken);
if (string.IsNullOrEmpty(key) && _bufferCount == 0)
await ReadNextPairAsyncImpl(cancellationToken);
if (ReadSucceded())
{
return null;
return new KeyValuePair<string, string>(_currentKey, _currentValue);
}
var value = await ReadWordAsync('&', ValueLengthLimit, cancellationToken);
return new KeyValuePair<string, string>(key, value);
return null;
}
private string ReadWord(char seperator, int limit)
private async Task ReadNextPairAsyncImpl(CancellationToken cancellationToken = new CancellationToken())
{
while (true)
{
// Empty
if (_bufferCount == 0)
{
Buffer();
}
string word;
if (ReadChar(seperator, limit, out word))
{
return word;
}
}
}
private async Task<string> ReadWordAsync(char seperator, int limit, CancellationToken cancellationToken)
{
while (true)
StartReadNextPair();
while (!_endOfStream)
{
// Empty
if (_bufferCount == 0)
{
await BufferAsync(cancellationToken);
}
string word;
if (ReadChar(seperator, limit, out word))
if (TryReadNextPair())
{
return word;
break;
}
}
}
private void StartReadNextPair()
{
_currentKey = null;
_currentValue = null;
}
private bool TryReadNextPair()
{
if (_currentKey == null)
{
if (!TryReadWord('=', KeyLengthLimit, out _currentKey))
{
return false;
}
if (_bufferCount == 0)
{
return false;
}
}
if (_currentValue == null)
{
if (!TryReadWord('&', ValueLengthLimit, out _currentValue))
{
return false;
}
}
return true;
}
private bool TryReadWord(char seperator, int limit, out string value)
{
do
{
if (ReadChar(seperator, limit, out value))
{
return true;
}
} while (_bufferCount > 0);
return false;
}
private bool ReadChar(char seperator, int limit, out string word)
{
// End
@ -198,6 +240,7 @@ namespace Microsoft.AspNetCore.WebUtilities
{
_bufferOffset = 0;
_bufferCount = _reader.Read(_buffer, 0, _buffer.Length);
_endOfStream = _bufferCount == 0;
}
private async Task BufferAsync(CancellationToken cancellationToken)
@ -206,6 +249,7 @@ namespace Microsoft.AspNetCore.WebUtilities
cancellationToken.ThrowIfCancellationRequested();
_bufferOffset = 0;
_bufferCount = await _reader.ReadAsync(_buffer, 0, _buffer.Length);
_endOfStream = _bufferCount == 0;
}
/// <summary>
@ -215,17 +259,11 @@ namespace Microsoft.AspNetCore.WebUtilities
public Dictionary<string, StringValues> ReadForm()
{
var accumulator = new KeyValueAccumulator();
var pair = ReadNextPair();
while (pair.HasValue)
while (!_endOfStream)
{
accumulator.Append(pair.Value.Key, pair.Value.Value);
if (accumulator.Count > KeyCountLimit)
{
throw new InvalidDataException($"Form key count limit {KeyCountLimit} exceeded.");
}
pair = ReadNextPair();
ReadNextPairImpl();
Append(ref accumulator);
}
return accumulator.GetResults();
}
@ -237,18 +275,29 @@ namespace Microsoft.AspNetCore.WebUtilities
public async Task<Dictionary<string, StringValues>> ReadFormAsync(CancellationToken cancellationToken = new CancellationToken())
{
var accumulator = new KeyValueAccumulator();
var pair = await ReadNextPairAsync(cancellationToken);
while (pair.HasValue)
while (!_endOfStream)
{
accumulator.Append(pair.Value.Key, pair.Value.Value);
await ReadNextPairAsyncImpl(cancellationToken);
Append(ref accumulator);
}
return accumulator.GetResults();
}
private bool ReadSucceded()
{
return _currentKey != null && _currentValue != null;
}
private void Append(ref KeyValueAccumulator accumulator)
{
if (ReadSucceded())
{
accumulator.Append(_currentKey, _currentValue);
if (accumulator.Count > KeyCountLimit)
{
throw new InvalidDataException($"Form key count limit {KeyCountLimit} exceeded.");
}
pair = await ReadNextPairAsync(cancellationToken);
}
return accumulator.GetResults();
}
public void Dispose()

22
test/Microsoft.AspNetCore.WebUtilities.Tests/FormReaderAsyncTest.cs Normal file
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@ -0,0 +1,22 @@
// 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.Collections.Generic;
using System.Threading.Tasks;
using Microsoft.Extensions.Primitives;
namespace Microsoft.AspNetCore.WebUtilities
{
public class FormReaderAsyncTest : FormReaderTests
{
protected override async Task<Dictionary<string, StringValues>> ReadFormAsync(FormReader reader)
{
return await reader.ReadFormAsync();
}
protected override async Task<KeyValuePair<string, string>?> ReadPair(FormReader reader)
{
return await reader.ReadNextPairAsync();
}
}
}

67
test/Microsoft.AspNetCore.WebUtilities.Tests/FormReaderTests.cs
View File

@ -1,10 +1,11 @@
// 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.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Microsoft.Extensions.Primitives;
using Xunit;
namespace Microsoft.AspNetCore.WebUtilities
@ -18,7 +19,7 @@ namespace Microsoft.AspNetCore.WebUtilities
{
var body = MakeStream(bufferRequest, "=bar");
var formCollection = await new FormReader(body).ReadFormAsync();
var formCollection = await ReadFormAsync(new FormReader(body));
Assert.Equal("bar", formCollection[""].ToString());
}
@ -30,7 +31,7 @@ namespace Microsoft.AspNetCore.WebUtilities
{
var body = MakeStream(bufferRequest, "=bar&baz=2");
var formCollection = await new FormReader(body).ReadFormAsync();
var formCollection = await ReadFormAsync(new FormReader(body));
Assert.Equal("bar", formCollection[""].ToString());
Assert.Equal("2", formCollection["baz"].ToString());
@ -43,7 +44,7 @@ namespace Microsoft.AspNetCore.WebUtilities
{
var body = MakeStream(bufferRequest, "foo=");
var formCollection = await new FormReader(body).ReadFormAsync();
var formCollection = await ReadFormAsync(new FormReader(body));
Assert.Equal("", formCollection["foo"].ToString());
}
@ -55,7 +56,7 @@ namespace Microsoft.AspNetCore.WebUtilities
{
var body = MakeStream(bufferRequest, "foo=&baz=2");
var formCollection = await new FormReader(body).ReadFormAsync();
var formCollection = await ReadFormAsync(new FormReader(body));
Assert.Equal("", formCollection["foo"].ToString());
Assert.Equal("2", formCollection["baz"].ToString());
@ -68,7 +69,7 @@ namespace Microsoft.AspNetCore.WebUtilities
{
var body = MakeStream(bufferRequest, "foo=1&bar=2&baz=3&baz=4");
var formCollection = await new FormReader(body) { KeyCountLimit = 3 }.ReadFormAsync();
var formCollection = await ReadFormAsync(new FormReader(body) { KeyCountLimit = 3 });
Assert.Equal("1", formCollection["foo"].ToString());
Assert.Equal("2", formCollection["bar"].ToString());
@ -84,7 +85,7 @@ namespace Microsoft.AspNetCore.WebUtilities
var body = MakeStream(bufferRequest, "foo=1&baz=2&bar=3&baz=4&baf=5");
var exception = await Assert.ThrowsAsync<InvalidDataException>(
() => new FormReader(body) { KeyCountLimit = 3 }.ReadFormAsync());
() => ReadFormAsync(new FormReader(body) { KeyCountLimit = 3 }));
Assert.Equal("Form key count limit 3 exceeded.", exception.Message);
}
@ -95,7 +96,7 @@ namespace Microsoft.AspNetCore.WebUtilities
{
var body = MakeStream(bufferRequest, "foo=1&bar=2&baz=3&baz=4");
var formCollection = await new FormReader(body) { KeyLengthLimit = 10 }.ReadFormAsync();
var formCollection = await ReadFormAsync(new FormReader(body) { KeyLengthLimit = 10 });
Assert.Equal("1", formCollection["foo"].ToString());
Assert.Equal("2", formCollection["bar"].ToString());
@ -111,7 +112,7 @@ namespace Microsoft.AspNetCore.WebUtilities
var body = MakeStream(bufferRequest, "foo=1&baz1234567890=2");
var exception = await Assert.ThrowsAsync<InvalidDataException>(
() => new FormReader(body) { KeyLengthLimit = 10 }.ReadFormAsync());
() => ReadFormAsync(new FormReader(body) { KeyLengthLimit = 10 }));
Assert.Equal("Form key or value length limit 10 exceeded.", exception.Message);
}
@ -122,7 +123,7 @@ namespace Microsoft.AspNetCore.WebUtilities
{
var body = MakeStream(bufferRequest, "foo=1&bar=1234567890&baz=3&baz=4");
var formCollection = await new FormReader(body) { ValueLengthLimit = 10 }.ReadFormAsync();
var formCollection = await ReadFormAsync(new FormReader(body) { ValueLengthLimit = 10 });
Assert.Equal("1", formCollection["foo"].ToString());
Assert.Equal("1234567890", formCollection["bar"].ToString());
@ -138,10 +139,54 @@ namespace Microsoft.AspNetCore.WebUtilities
var body = MakeStream(bufferRequest, "foo=1&baz=1234567890123");
var exception = await Assert.ThrowsAsync<InvalidDataException>(
() => new FormReader(body) { ValueLengthLimit = 10 }.ReadFormAsync());
() => ReadFormAsync(new FormReader(body) { ValueLengthLimit = 10 }));
Assert.Equal("Form key or value length limit 10 exceeded.", exception.Message);
}
[Theory]
[InlineData(true)]
[InlineData(false)]
public async Task ReadNextPair_ReadsAllPairs(bool bufferRequest)
{
var body = MakeStream(bufferRequest, "foo=&baz=2");
var reader = new FormReader(body);
var pair = (KeyValuePair<string, string>)await ReadPair(reader);
Assert.Equal("foo", pair.Key);
Assert.Equal("", pair.Value);
pair = (KeyValuePair<string, string>)await ReadPair(reader);
Assert.Equal("baz", pair.Key);
Assert.Equal("2", pair.Value);
Assert.Null(await ReadPair(reader));
}
[Theory]
[InlineData(true)]
[InlineData(false)]
public async Task ReadNextPair_ReturnsNullOnEmptyStream(bool bufferRequest)
{
var body = MakeStream(bufferRequest, "");
var reader = new FormReader(body);
Assert.Null(await ReadPair(reader));
}
protected virtual Task<Dictionary<string, StringValues>> ReadFormAsync(FormReader reader)
{
return Task.FromResult(reader.ReadForm());
}
protected virtual Task<KeyValuePair<string, string>?> ReadPair(FormReader reader)
{
return Task.FromResult(reader.ReadNextPair());
}
private static Stream MakeStream(bool bufferRequest, string text)
{
var formContent = Encoding.UTF8.GetBytes(text);

2
test/Microsoft.AspNetCore.WebUtilities.Tests/NonSeekableReadStream.cs
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@ -61,11 +61,13 @@ namespace Microsoft.AspNetCore.WebUtilities
public override int Read(byte[] buffer, int offset, int count)
{
count = Math.Max(count, 1);
return _inner.Read(buffer, offset, count);
}
public override Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
{
count = Math.Max(count, 1);
return _inner.ReadAsync(buffer, offset, count, cancellationToken);
}
}