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Introduct ConcurrentTLruCache
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7 files changed

+560
-28
lines changed

7 files changed

+560
-28
lines changed

‎src/ImageSharp.Web/Caching/LruCache/ConcurrentTLruCache{TKey,TValue}.cs‎

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‎src/ImageSharp.Web/Caching/LruCache/ItemDestination.cs‎

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// Copyright (c) Six Labors.
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// Licensed under the Apache License, Version 2.0.
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namespace SixLabors.ImageSharp.Web.Caching
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{
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internal enum ItemDestination
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{
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Warm,
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Cold,
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Remove
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}
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}

‎src/ImageSharp.Web/Caching/LruCache/LongTickCountLruItem{TKey,TValue}.cs‎

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// Copyright (c) Six Labors.
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// Licensed under the Apache License, Version 2.0.
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namespace SixLabors.ImageSharp.Web.Caching
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{
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internal class LongTickCountLruItem<TKey, TValue>
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{
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private volatile bool wasAccessed;
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private volatile bool wasRemoved;
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#pragma warning disable SA1401 // Fields should be private
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public readonly TKey Key;
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public readonly TValue Value;
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#pragma warning restore SA1401 // Fields should be private
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public LongTickCountLruItem(TKey k, TValue v, long tickCount)
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{
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this.Key = k;
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this.Value = v;
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this.TickCount = tickCount;
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}
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public long TickCount { get; set; }
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public bool WasAccessed
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{
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get => this.wasAccessed;
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set => this.wasAccessed = value;
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}
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public bool WasRemoved
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{
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get => this.wasRemoved;
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set => this.wasRemoved = value;
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}
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}
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}

‎src/ImageSharp.Web/Caching/LruCache/README.md‎

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The TLRU cache implementation was adapted from the excellent BitFaster.Caching
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by Alex Peck (MIT license).
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https://github.com/bitfaster/BitFaster.Caching
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We have chosen to avoid a direct dependency at this time so that we can independantly
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adjust internal mechanisms when required to suit our caching requirements.
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API compatibility wil be preserved and we may introduce the dependancy on a later date if no
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changes are required.

‎src/ImageSharp.Web/Caching/LruCache/TLruLongTicksPolicy{TKey,TValue}.cs‎

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// Copyright (c) Six Labors.
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// Licensed under the Apache License, Version 2.0.
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using System;
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using System.Diagnostics;
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using System.Runtime.CompilerServices;
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namespace SixLabors.ImageSharp.Web.Caching
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{
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/// <summary>
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/// Time aware Least Recently Used (TLRU) is a variant of LRU which discards the least
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/// recently used items first, and any item that has expired.
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/// </summary>
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/// <remarks>
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/// This class measures time using stopwatch.
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/// </remarks>
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internal readonly struct TLruLongTicksPolicy<TKey, TValue>
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{
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private readonly long timeToLive;
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public TLruLongTicksPolicy(TimeSpan timeToLive)
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{
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this.timeToLive = timeToLive.Ticks;
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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public LongTickCountLruItem<TKey, TValue> CreateItem(TKey key, TValue value)
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{
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return new LongTickCountLruItem<TKey, TValue>(key, value, Stopwatch.GetTimestamp());
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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public void Touch(LongTickCountLruItem<TKey, TValue> item)
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{
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item.WasAccessed = true;
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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public bool ShouldDiscard(LongTickCountLruItem<TKey, TValue> item)
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{
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if (Stopwatch.GetTimestamp() - item.TickCount > this.timeToLive)
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{
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return true;
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}
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return false;
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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public ItemDestination RouteHot(LongTickCountLruItem<TKey, TValue> item)
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{
52+
if (this.ShouldDiscard(item))
53+
{
54+
return ItemDestination.Remove;
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}
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if (item.WasAccessed)
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{
59+
return ItemDestination.Warm;
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}
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return ItemDestination.Cold;
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
66+
public ItemDestination RouteWarm(LongTickCountLruItem<TKey, TValue> item)
67+
{
68+
if (this.ShouldDiscard(item))
69+
{
70+
return ItemDestination.Remove;
71+
}
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if (item.WasAccessed)
74+
{
75+
return ItemDestination.Warm;
76+
}
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return ItemDestination.Cold;
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}
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81+
[MethodImpl(MethodImplOptions.AggressiveInlining)]
82+
public ItemDestination RouteCold(LongTickCountLruItem<TKey, TValue> item)
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{
84+
if (this.ShouldDiscard(item))
85+
{
86+
return ItemDestination.Remove;
87+
}
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89+
if (item.WasAccessed)
90+
{
91+
return ItemDestination.Warm;
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}
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return ItemDestination.Remove;
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}
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}
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}

‎src/ImageSharp.Web/ImageSharp.Web.csproj‎

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@@ -1,4 +1,4 @@
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<Project Sdk="Microsoft.NET.Sdk">
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<Project Sdk="Microsoft.NET.Sdk">
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<PropertyGroup>
44
<AssemblyTitle>SixLabors.ImageSharp.Web</AssemblyTitle>
@@ -26,7 +26,6 @@
2626
</ItemGroup>
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<ItemGroup>
29-
<PackageReference Include="BitFaster.Caching" Version="1.0.1" />
3029
<PackageReference Include="Microsoft.IO.RecyclableMemoryStream" />
3130
<PackageReference Include="Microsoft.SourceLink.GitHub" />
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<PackageReference Include="MinVer" PrivateAssets="All" />

‎src/ImageSharp.Web/Middleware/ImageSharpMiddleware.cs‎

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@@ -9,7 +9,6 @@
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using System.Linq;
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using System.Text;
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using System.Threading.Tasks;
12-
using BitFaster.Caching.Lru;
1312
using Microsoft.AspNetCore.Http;
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using Microsoft.Extensions.Logging;
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using Microsoft.Extensions.Options;
@@ -36,20 +35,20 @@ public class ImageSharpMiddleware
3635
/// <summary>
3736
/// Used to temporarily store source metadata reads to reduce the overhead of cache lookups.
3837
/// </summary>
39-
private static readonly ConcurrentTLru<string, ImageMetadata> SourceMetadataLru
40-
= new ConcurrentTLru<string, ImageMetadata>(1024, TimeSpan.FromMinutes(5));
38+
private static readonly ConcurrentTLruCache<string, ImageMetadata> SourceMetadataLru
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= new ConcurrentTLruCache<string, ImageMetadata>(1024, TimeSpan.FromMinutes(5));
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4241
/// <summary>
4342
/// Used to temporarily store cache resolver reads to reduce the overhead of cache lookups.
4443
/// </summary>
45-
private static readonly ConcurrentTLru<string, IImageCacheResolver> CacheResolverLru
46-
= new ConcurrentTLru<string, IImageCacheResolver>(1024, TimeSpan.FromMinutes(5));
44+
private static readonly ConcurrentTLruCache<string, IImageCacheResolver> CacheResolverLru
45+
= new ConcurrentTLruCache<string, IImageCacheResolver>(1024, TimeSpan.FromMinutes(5));
4746

4847
/// <summary>
4948
/// Used to temporarily store cache metadata reads to reduce the overhead of cache lookups.
5049
/// </summary>
51-
private static readonly ConcurrentTLru<string, ImageCacheMetadata> CacheMetadataLru
52-
= new ConcurrentTLru<string, ImageCacheMetadata>(1024, TimeSpan.FromMinutes(5));
50+
private static readonly ConcurrentTLruCache<string, ImageCacheMetadata> CacheMetadataLru
51+
= new ConcurrentTLruCache<string, ImageCacheMetadata>(1024, TimeSpan.FromMinutes(5));
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5453
/// <summary>
5554
/// The function processing the Http request.
@@ -268,10 +267,19 @@ private async Task ProcessRequestAsync(
268267
{
269268
ImageCacheMetadata cachedImageMetadata = default;
270269
outStream = new RecyclableMemoryStream(this.options.MemoryStreamManager);
271-
using (Stream inStream = await sourceImageResolver.OpenReadAsync())
270+
IImageFormat format;
271+
272+
// 14.9.3 CacheControl Max-Age
273+
// Check to see if the source metadata has a CacheControl Max-Age value
274+
// and use it to override the default max age from our options.
275+
TimeSpan maxAge = this.options.BrowserMaxAge;
276+
if (!sourceImageMetadata.CacheControlMaxAge.Equals(TimeSpan.MinValue))
272277
{
273-
IImageFormat format;
278+
maxAge = sourceImageMetadata.CacheControlMaxAge;
279+
}
274280

281+
using (Stream inStream = await sourceImageResolver.OpenReadAsync())
282+
{
275283
// No commands? We simply copy the stream across.
276284
if (commands.Count == 0)
277285
{
@@ -295,31 +303,22 @@ private async Task ProcessRequestAsync(
295303
image.Save(outStream);
296304
format = image.Format;
297305
}
298-
299-
// 14.9.3 CacheControl Max-Age
300-
// Check to see if the source metadata has a CacheControl Max-Age value
301-
// and use it to override the default max age from our options.
302-
TimeSpan maxAge = this.options.BrowserMaxAge;
303-
if (!sourceImageMetadata.CacheControlMaxAge.Equals(TimeSpan.MinValue))
304-
{
305-
maxAge = sourceImageMetadata.CacheControlMaxAge;
306-
}
307-
308-
cachedImageMetadata = new ImageCacheMetadata(
309-
sourceImageMetadata.LastWriteTimeUtc,
310-
DateTime.UtcNow,
311-
format.DefaultMimeType,
312-
maxAge,
313-
outStream.Length);
314306
}
315307

316308
// Allow for any further optimization of the image.
317309
outStream.Position = 0;
318-
string contentType = cachedImageMetadata.ContentType;
310+
string contentType = format.DefaultMimeType;
319311
string extension = this.formatUtilities.GetExtensionFromContentType(contentType);
320312
await this.options.OnProcessedAsync.Invoke(new ImageProcessingContext(context, outStream, commands, contentType, extension));
321313
outStream.Position = 0;
322314

315+
cachedImageMetadata = new ImageCacheMetadata(
316+
sourceImageMetadata.LastWriteTimeUtc,
317+
DateTime.UtcNow,
318+
contentType,
319+
maxAge,
320+
outStream.Length);
321+
323322
// Save the image to the cache and send the response to the caller.
324323
await this.cache.SetAsync(key, outStream, cachedImageMetadata);
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