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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Net.Http.HPack;
using System.Reflection;
using System.Text;
using Xunit;
namespace System.Net.Http.Unit.Tests.HPack
{
public class DynamicTableTest
{
private readonly HeaderField _header1 = new HeaderField(staticTableIndex: null, Encoding.ASCII.GetBytes("header-1"), Encoding.ASCII.GetBytes("value1"));
private readonly HeaderField _header2 = new HeaderField(staticTableIndex: null, Encoding.ASCII.GetBytes("header-02"), Encoding.ASCII.GetBytes("value_2"));
[Fact]
public void DynamicTable_IsInitiallyEmpty()
{
DynamicTable dynamicTable = new DynamicTable(4096);
Assert.Equal(0, dynamicTable.Count);
Assert.Equal(0, dynamicTable.Size);
Assert.Equal(4096, dynamicTable.MaxSize);
}
[Fact]
public void DynamicTable_Count_IsNumberOfEntriesInDynamicTable()
{
DynamicTable dynamicTable = new DynamicTable(4096);
dynamicTable.Insert(_header1.Name, _header1.Value);
Assert.Equal(1, dynamicTable.Count);
dynamicTable.Insert(_header2.Name, _header2.Value);
Assert.Equal(2, dynamicTable.Count);
}
[Fact]
public void DynamicTable_Size_IsCurrentDynamicTableSize()
{
DynamicTable dynamicTable = new DynamicTable(4096);
Assert.Equal(0, dynamicTable.Size);
dynamicTable.Insert(_header1.Name, _header1.Value);
Assert.Equal(_header1.Length, dynamicTable.Size);
dynamicTable.Insert(_header2.Name, _header2.Value);
Assert.Equal(_header1.Length + _header2.Length, dynamicTable.Size);
}
[Fact]
public void DynamicTable_FirstEntry_IsMostRecentEntry()
{
DynamicTable dynamicTable = new DynamicTable(4096);
dynamicTable.Insert(_header1.Name, _header1.Value);
dynamicTable.Insert(_header2.Name, _header2.Value);
VerifyTableEntries(dynamicTable, _header2, _header1);
}
[Fact]
public void BoundsCheck_ThrowsIndexOutOfRangeException()
{
DynamicTable dynamicTable = new DynamicTable(4096);
Assert.Throws<IndexOutOfRangeException>(() => dynamicTable[0]);
dynamicTable.Insert(_header1.Name, _header1.Value);
Assert.Throws<IndexOutOfRangeException>(() => dynamicTable[1]);
}
[Fact]
public void DynamicTable_InsertEntryLargerThanMaxSize_NoOp()
{
DynamicTable dynamicTable = new DynamicTable(_header1.Length - 1);
dynamicTable.Insert(_header1.Name, _header1.Value);
Assert.Equal(0, dynamicTable.Count);
Assert.Equal(0, dynamicTable.Size);
}
[Fact]
public void DynamicTable_InsertEntryLargerThanRemainingSpace_NoOp()
{
DynamicTable dynamicTable = new DynamicTable(_header1.Length);
dynamicTable.Insert(_header1.Name, _header1.Value);
VerifyTableEntries(dynamicTable, _header1);
dynamicTable.Insert(_header2.Name, _header2.Value);
Assert.Equal(0, dynamicTable.Count);
Assert.Equal(0, dynamicTable.Size);
}
[Theory]
[InlineData(0)]
[InlineData(1)]
[InlineData(2)]
[InlineData(3)]
public void DynamicTable_WrapsRingBuffer_Success(int targetInsertIndex)
{
FieldInfo insertIndexField = typeof(DynamicTable).GetField("_insertIndex", BindingFlags.NonPublic | BindingFlags.Instance);
DynamicTable table = new DynamicTable(maxSize: 256);
Stack<byte[]> insertedHeaders = new Stack<byte[]>();
// Insert into dynamic table until its insert index into its ring buffer loops back to 0.
do
{
InsertOne();
}
while ((int)insertIndexField.GetValue(table) != 0);
// Finally loop until the insert index reaches the target.
while ((int)insertIndexField.GetValue(table) != targetInsertIndex)
{
InsertOne();
}
void InsertOne()
{
byte[] data = Encoding.ASCII.GetBytes($"header-{insertedHeaders.Count}");
insertedHeaders.Push(data);
table.Insert(data, data);
}
// Now check to see that we can retrieve the remaining headers.
// Some headers will have been evacuated from the table during this process, so we don't exhaust the entire insertedHeaders stack.
Assert.True(table.Count > 0);
Assert.True(table.Count < insertedHeaders.Count);
for (int i = 0; i < table.Count; ++i)
{
HeaderField dynamicField = table[i];
byte[] expectedData = insertedHeaders.Pop();
Assert.True(expectedData.AsSpan().SequenceEqual(dynamicField.Name));
Assert.True(expectedData.AsSpan().SequenceEqual(dynamicField.Value));
}
}
[Theory]
[MemberData(nameof(CreateResizeData))]
public void DynamicTable_Resize_Success(int initialMaxSize, int finalMaxSize, int insertSize)
{
// This is purely to make it simple to perfectly reach our initial max size to test growing a full but non-wrapping buffer.
Debug.Assert((insertSize % 64) == 0, $"{nameof(insertSize)} must be a multiple of 64 ({nameof(HeaderField)}.{nameof(HeaderField.RfcOverhead)} * 2)");
DynamicTable dynamicTable = new DynamicTable(maxSize: initialMaxSize);
int insertedSize = 0;
while (insertedSize != insertSize)
{
byte[] data = Encoding.ASCII.GetBytes($"header-{dynamicTable.Size}".PadRight(16, ' '));
Debug.Assert(data.Length == 16);
dynamicTable.Insert(data, data);
insertedSize += data.Length * 2 + HeaderField.RfcOverhead;
}
List<HeaderField> headers = new List<HeaderField>();
for (int i = 0; i < dynamicTable.Count; ++i)
{
headers.Add(dynamicTable[i]);
}
dynamicTable.Resize(finalMaxSize);
int expectedCount = Math.Min(finalMaxSize / 64, headers.Count);
Assert.Equal(expectedCount, dynamicTable.Count);
for (int i = 0; i < dynamicTable.Count; ++i)
{
Assert.True(headers[i].Name.AsSpan().SequenceEqual(dynamicTable[i].Name));
Assert.True(headers[i].Value.AsSpan().SequenceEqual(dynamicTable[i].Value));
}
}
[Fact]
public void DynamicTable_ResizingEvictsOldestEntries()
{
DynamicTable dynamicTable = new DynamicTable(4096);
dynamicTable.Insert(_header1.Name, _header1.Value);
dynamicTable.Insert(_header2.Name, _header2.Value);
VerifyTableEntries(dynamicTable, _header2, _header1);
dynamicTable.Resize(_header2.Length);
VerifyTableEntries(dynamicTable, _header2);
}
[Fact]
public void DynamicTable_ResizingToZeroEvictsAllEntries()
{
DynamicTable dynamicTable = new DynamicTable(4096);
dynamicTable.Insert(_header1.Name, _header1.Value);
dynamicTable.Insert(_header2.Name, _header2.Value);
dynamicTable.Resize(0);
Assert.Equal(0, dynamicTable.Count);
Assert.Equal(0, dynamicTable.Size);
}
[Fact]
public void DynamicTable_CanBeResizedToLargerMaxSize()
{
DynamicTable dynamicTable = new DynamicTable(_header1.Length);
dynamicTable.Insert(_header1.Name, _header1.Value);
dynamicTable.Insert(_header2.Name, _header2.Value);
// _header2 is larger than _header1, so an attempt at inserting it
// would first clear the table then return without actually inserting it,
// given it is larger than the current max size.
Assert.Equal(0, dynamicTable.Count);
Assert.Equal(0, dynamicTable.Size);
dynamicTable.Resize(dynamicTable.MaxSize + _header2.Length);
dynamicTable.Insert(_header2.Name, _header2.Value);
VerifyTableEntries(dynamicTable, _header2);
}
public static IEnumerable<object[]> CreateResizeData()
{
int[] values = new[] { 128, 256, 384, 512 };
return from initialMaxSize in values
from finalMaxSize in values
from insertSize in values
select new object[] { initialMaxSize, finalMaxSize, insertSize };
}
private void VerifyTableEntries(DynamicTable dynamicTable, params HeaderField[] entries)
{
Assert.Equal(entries.Length, dynamicTable.Count);
Assert.Equal(entries.Sum(e => e.Length), dynamicTable.Size);
for (int i = 0; i < entries.Length; i++)
{
HeaderField headerField = dynamicTable[i];
Assert.NotSame(entries[i].Name, headerField.Name);
Assert.Equal(entries[i].Name, headerField.Name);
Assert.NotSame(entries[i].Value, headerField.Value);
Assert.Equal(entries[i].Value, headerField.Value);
}
}
}
}
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