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Remove double lookups on SizeLimitedCache<K, V>, improve performance #9949

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Merged
merged 8 commits into from
Mar 6, 2025
Merged

Remove double lookups on SizeLimitedCache<K, V>, improve performance #9949

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e47d652
Fix double lookup on Get
h3xds1nz Oct 13, 2024
3ab3000
Mark fields that could be readonly, functions that could be static
h3xds1nz Oct 13, 2024
6bb5f47
Fix double lookup on Add
h3xds1nz Oct 13, 2024
6038a66
Naming cleanup, seal the class
h3xds1nz Oct 13, 2024
e07abea
Change the fields order
h3xds1nz Oct 13, 2024
257c32a
Seal Node as well, use auto properties
h3xds1nz Oct 13, 2024
0bcfdea
Fix additional lookup on Remove
h3xds1nz Oct 13, 2024
ebcfa79
Whitespaces
h3xds1nz Feb 27, 2025
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14 changes: 7 additions & 7 deletions src/Microsoft.DotNet.Wpf/src/PresentationCore/MS/internal/FontCache/FontSource.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -166,9 +166,9 @@ public UnmanagedMemoryStream GetUnmanagedStream()
byte[] bits;

// Try our cache first.
lock (_resourceCache)
lock (s_resourceCache)
{
bits = _resourceCache.Get(_fontUri);
bits = s_resourceCache.Get(_fontUri);
}

if (bits == null)
Expand Down Expand Up @@ -202,9 +202,9 @@ public UnmanagedMemoryStream GetUnmanagedStream()
fontStream?.Close();
}

lock (_resourceCache)
lock (s_resourceCache)
{
_resourceCache.Add(_fontUri, bits, false);
s_resourceCache.Add(_fontUri, bits, false);
}

return ByteArrayToUnmanagedStream(bits);
Expand Down Expand Up @@ -239,9 +239,9 @@ public Stream GetStream()
byte[] bits;

// Try our cache first.
lock (_resourceCache)
lock (s_resourceCache)
{
bits = _resourceCache.Get(_fontUri);
bits = s_resourceCache.Get(_fontUri);
}

if (bits != null)
Expand Down Expand Up @@ -423,7 +423,7 @@ protected override void Dispose(bool disposing)

private Uri _fontUri;

private static SizeLimitedCache<Uri, byte[]> _resourceCache = new SizeLimitedCache<Uri, byte[]>(MaximumCacheItems);
private static readonly SizeLimitedCache<Uri, byte[]> s_resourceCache = new(MaximumCacheItems);

/// <summary>
/// The maximum number of fonts downloaded from pack:// Uris.
Expand Down
2 changes: 1 addition & 1 deletion src/Microsoft.DotNet.Wpf/src/PresentationCore/MS/internal/Shaping/GlyphingCache.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -30,7 +30,7 @@ namespace MS.Internal.Shaping
/// </summary>
internal class GlyphingCache
{
private SizeLimitedCache<Typeface, TypefaceMap> _sizeLimitedCache;
private readonly SizeLimitedCache<Typeface, TypefaceMap> _sizeLimitedCache;

internal GlyphingCache(int capacity)
{
Expand Down
113 changes: 33 additions & 80 deletions src/Microsoft.DotNet.Wpf/src/Shared/MS/Internal/SizeLimitedCache.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,7 @@ namespace MS.Internal
/// changed, it gets moved to the end of the list. Also, permanent items,
/// though in the hash table, are NOT in the linked list.
/// </remarks>
internal class SizeLimitedCache<K, V>
internal sealed class SizeLimitedCache<K, V>
{
//*****************************************************
// Constructors
Expand All @@ -40,12 +40,13 @@ public SizeLimitedCache(int maximumItems)
_permanentCount = 0;

// set up an empty list.
// the _begin and _end nodes are empty nodes marking the begin and
// end of the list.
// the _begin and _end nodes are empty nodes marking the begin and end of the list.
_begin = new Node(default(K), default(V), false);
_end = new Node(default(K), default(V), false);
_begin.Next = _end;

_begin.Next = _end;
_end.Previous = _begin;

_nodeLookup = new Dictionary<K, Node>();
}

Expand Down Expand Up @@ -85,20 +86,13 @@ public int MaximumItems
/// </param>
public void Add(K key, V resource, bool isPermanent)
{
ArgumentNullException.ThrowIfNull(key, nameof(key));
ArgumentNullException.ThrowIfNull(resource, nameof(resource));

if ( (object)key == null)
{
throw new ArgumentNullException(nameof(key));
}
if ( (object)resource == null)
{
throw new ArgumentNullException(nameof(resource));
}

// note: [] throws, thus we should check if its in the dictionary first.
if (!_nodeLookup.ContainsKey(key))
// Lookup first
if (!_nodeLookup.TryGetValue(key, out Node node))
{
Node node = new Node(key, resource, isPermanent);
node = new Node(key, resource, isPermanent);
if (!isPermanent)
{
if (IsFull())
Expand All @@ -111,11 +105,11 @@ public void Add(K key, V resource, bool isPermanent)
{
_permanentCount++;
}

_nodeLookup[key] = node;
}
else
{
Node node = _nodeLookup[key];
if (!node.IsPermanent)
{
RemoveFromList(node);
Expand Down Expand Up @@ -151,27 +145,15 @@ public void Add(K key, V resource, bool isPermanent)
/// </param>
public void Remove(K key)
{
if ( (object)key == null)
{
throw new ArgumentNullException(nameof(key));
}
ArgumentNullException.ThrowIfNull(key, nameof(key));

// note: [] throws, thus we should check if its in the dictionary first.
if (!_nodeLookup.ContainsKey(key))
{
if (!_nodeLookup.Remove(key, out Node node))
return;
}
Node node = _nodeLookup[key];

_nodeLookup.Remove(key);
if (!node.IsPermanent)
{
RemoveFromList(node);
}
else
{
_permanentCount--;
}
}

/// <summary>
Expand All @@ -187,17 +169,10 @@ public void Remove(K key)
/// </returns>
public V Get(K key)
{
if ( (object)key == null)
{
throw new ArgumentNullException(nameof(key));
}
ArgumentNullException.ThrowIfNull(key, nameof(key));

// note: [] throws, thus we should check if its in the dictionary first.
if (!_nodeLookup.ContainsKey(key))
{
return default(V);
}
Node node = _nodeLookup[key];
if (!_nodeLookup.TryGetValue(key, out Node node))
return default;

if (!node.IsPermanent)
{
Expand All @@ -218,7 +193,9 @@ public V Get(K key)
private void RemoveOldest()
{
Node node = _begin.Next;

_nodeLookup.Remove(node.Key);

RemoveFromList(node);
}

Expand All @@ -232,6 +209,7 @@ private void InsertAtEnd(Node node)
{
node.Next = _end;
node.Previous = _end.Previous;

node.Previous.Next = node;
_end.Previous = node;
}
Expand All @@ -242,7 +220,7 @@ private void InsertAtEnd(Node node)
/// <param name="node">
/// The node to remove
/// </param>
private void RemoveFromList(Node node)
private static void RemoveFromList(Node node)
{
node.Previous.Next = node.Next;
node.Next.Previous = node.Previous;
Expand All @@ -257,13 +235,13 @@ private void RemoveFromList(Node node)
/// </returns>
private bool IsFull()
{
return (_nodeLookup.Count - _permanentCount >= _maximumItems);
return (_nodeLookup.Count - _permanentCount) >= _maximumItems;
}

/// <summary>
/// Doubly linked list node class. Has 3 values: key, resource, permanence flag
/// </summary>
private class Node
private sealed class Node
{
public Node(K key, V resource, bool isPermanent)
{
Expand All @@ -272,59 +250,34 @@ public Node(K key, V resource, bool isPermanent)
IsPermanent = isPermanent;
}

public K Key
{
get { return _key; }
set { _key = value; }
}
public K Key { get; }

public V Resource
{
get { return _resource; }
set { _resource = value; }
}
public V Resource { get; set; }

public bool IsPermanent
{
get { return _isPermanent; }
set { _isPermanent = value; }
}
public bool IsPermanent { get; set; }

public Node Next
{
get { return _next; }
set { _next = value; }
}
public Node Next { get; set; }

public Node Previous
{
get { return _previous; }
set { _previous = value; }
}
public Node Previous { get; set; }

private V _resource;
private K _key;
private bool _isPermanent;
private Node _next;
private Node _previous;
}

//*****************************************************
// Private Fields
// ****************************************************

// the maximum nonpermanent items allowed
private int _maximumItems;

// need to keep a separate counter for permanent items
private int _permanentCount;

// the maximum nonpermanent items allowed
private readonly int _maximumItems;

// the _begin and _end nodes are empty nodes marking the begin and
// end of the list.
private Node _begin;
private Node _end;
private readonly Node _begin;
private readonly Node _end;

// the hashtable mapping keys to nodes
private Dictionary<K, Node> _nodeLookup;
private readonly Dictionary<K, Node> _nodeLookup;
}
}