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Merged
SimonCropp merged 1 commit into from
Oct 6, 2026
Merged

Perf: faster date reads, pooled string output and less per value work #416

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8 changes: 5 additions & 3 deletions src/Argon/JsonConvert.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -522,11 +522,13 @@ public static string SerializeObject(object? value, Type? type, Formatting forma

static string SerializeObjectInternal(object? value, Type? type, JsonSerializer serializer)
{
var builder = new StringBuilder(256);
var stringWriter = new StringWriter(builder, InvariantCulture);
// the text is read back before the buffer is returned to the pool, so the JSON writer
// must not close it
using var stringWriter = new PooledStringWriter();
using (var jsonWriter = new JsonTextWriter(stringWriter)
{
Formatting = serializer.Formatting.GetValueOrDefault()
Formatting = serializer.Formatting.GetValueOrDefault(),
CloseOutput = false
})
{
serializer.Serialize(jsonWriter, value, type);
Expand Down
5 changes: 5 additions & 0 deletions src/Argon/JsonSerializer.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -702,6 +702,11 @@ internal IReferenceResolver GetReferenceResolver() =>

internal static JsonConverter? GetMatchingConverter(IList<JsonConverter>? converters, Type type)
{
if (converters is ConverterListCache cache)
{
return cache.GetMatching(type);
}

if (converters != null)
{
// indexed loop: foreach over IList<T> boxes the List<T> enumerator, and this
Expand Down
63 changes: 58 additions & 5 deletions src/Argon/JsonTextReader.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -112,6 +112,26 @@ void ParseReadString(char quote, ReadType readType)
SetToken(text);
quoteChar = quote;
break;
case ReadType.ReadAsDateTime:
// an ISO date is parsed straight from the buffer. anything else becomes a string
// token for the caller to convert, as before
if (DateTimeUtils.TryParseDateTimeIso(stringReference.AsSpan(), out var dateTime))
{
SetToken(JsonToken.Date, dateTime, false);
quoteChar = quote;
break;
}

goto default;
case ReadType.ReadAsDateTimeOffset:
if (DateTimeUtils.TryParseDateTimeOffsetIso(stringReference.AsSpan(), out var dateTimeOffset))
{
SetToken(JsonToken.Date, dateTimeOffset, false);
quoteChar = quote;
break;
}

goto default;
case ReadType.ReadAsInt32:
case ReadType.ReadAsDecimal:
case ReadType.ReadAsDouble:
Expand Down Expand Up @@ -435,6 +455,8 @@ public override bool Read()
ProcessLineFeed();
break;
case ' ':
SkipSpaces();
break;
case StringUtils.Tab:
// eat
charPos++;
Expand Down Expand Up @@ -567,6 +589,8 @@ State.ArrayStart or
ProcessLineFeed();
break;
case ' ':
SkipSpaces();
break;
case StringUtils.Tab:
// eat
charPos++;
Expand Down Expand Up @@ -599,16 +623,17 @@ State.ArrayStart or
case ReadType.ReadAsString:
return Value;
case ReadType.ReadAsDateTime:
if (Value is DateTime time)
// already boxed as the token value, so hand that back rather than boxing again
if (Value is DateTime)
{
return time;
return Value;
}

return ReadDateTimeString((string?) Value);
case ReadType.ReadAsDateTimeOffset:
if (Value is DateTimeOffset offset)
if (Value is DateTimeOffset)
{
return offset;
return Value;
}

return ReadDateTimeOffsetString((string?) Value);
Expand Down Expand Up @@ -720,6 +745,8 @@ JsonReaderException CreateUnexpectedCharacterException(char c) =>
ProcessLineFeed();
break;
case ' ':
SkipSpaces();
break;
case StringUtils.Tab:
// eat
charPos++;
Expand Down Expand Up @@ -844,6 +871,8 @@ void ProcessValueComma()
ProcessLineFeed();
break;
case ' ':
SkipSpaces();
break;
case StringUtils.Tab:
// eat
charPos++;
Expand Down Expand Up @@ -1333,6 +1362,8 @@ bool ParsePostValue(bool ignoreComments)
SetStateBasedOnCurrent();
return false;
case ' ':
SkipSpaces();
break;
case StringUtils.Tab:
// eat
charPos++;
Expand Down Expand Up @@ -1402,6 +1433,8 @@ bool ParseObject()
ProcessLineFeed();
break;
case ' ':
SkipSpaces();
break;
case StringUtils.Tab:
// eat
charPos++;
Expand Down Expand Up @@ -1616,6 +1649,8 @@ bool ParseValue()
ProcessLineFeed();
break;
case ' ':
SkipSpaces();
break;
case StringUtils.Tab:
// eat
charPos++;
Expand Down Expand Up @@ -1645,6 +1680,21 @@ void ProcessLineFeed()
OnNewLine(charPos);
}

// Indentation is a run of spaces, so step over the whole run in one tight loop instead of
// going around the caller's switch once per space. The '\0' kept at charsUsed is not a space,
// so the scan always stops inside the buffer.
void SkipSpaces()
{
var buffer = charBuffer;
var position = charPos + 1;
while (buffer[position] == ' ')
{
position++;
}

charPos = position;
}

void ProcessCarriageReturn(bool append)
{
charPos++;
Expand Down Expand Up @@ -1680,8 +1730,11 @@ void EatWhitespace()
case StringUtils.LineFeed:
ProcessLineFeed();
break;
case ' ':
SkipSpaces();
break;
default:
if (currentChar == ' ' || char.IsWhiteSpace(currentChar))
if (char.IsWhiteSpace(currentChar))
{
charPos++;
}
Expand Down
123 changes: 123 additions & 0 deletions src/Argon/Linq/ConverterListCache.cs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,123 @@
// Copyright (c) 2007 James Newton-King. All rights reserved.
// Use of this source code is governed by The MIT License,
// as found in the license.md file.

/// <summary>
/// A converter list that remembers which converter matched each type.
/// </summary>
/// <remarks>
/// JToken.WriteTo hands its converter list to every token beneath it, and each JValue then asks
/// every converter in turn whether it converts the value's type. A document has thousands of
/// values but only a handful of distinct value types, so the answer is remembered per type for as
/// long as this list is in use. It is a list in its own right so that it can travel through the
/// public WriteTo signature unchanged.
/// </remarks>
[RequiresUnreferencedCode(MiscellaneousUtils.TrimWarning)]
[RequiresDynamicCode(MiscellaneousUtils.AotWarning)]
sealed class ConverterListCache(IList<JsonConverter> inner) :
IList<JsonConverter>
{
// a JValue holds one of a dozen or so CLR types, and a short linear probe is quicker than
// hashing the type. any types past this many are simply not remembered
const int capacity = 8;

struct Match
{
public Type Type;
public JsonConverter? Converter;
}

readonly Match[] matches = new Match[capacity];
int count;

internal static IList<JsonConverter> Wrap(IList<JsonConverter> converters)
{
if (converters.Count == 0 ||
converters is ConverterListCache)
{
return converters;
}

return new ConverterListCache(converters);
}

internal JsonConverter? GetMatching(Type type)
{
for (var index = 0; index < count; index++)
{
if (matches[index].Type == type)
{
return matches[index].Converter;
}
}

var converter = JsonSerializer.GetMatchingConverter(inner, type);
if (count < capacity)
{
matches[count].Type = type;
matches[count].Converter = converter;
count++;
}

return converter;
}

public int Count => inner.Count;

public bool IsReadOnly => inner.IsReadOnly;

public JsonConverter this[int index]
{
get => inner[index];
set
{
inner[index] = value;
count = 0;
}
}

public void Add(JsonConverter item)
{
inner.Add(item);
count = 0;
}

public void Clear()
{
inner.Clear();
count = 0;
}

public void Insert(int index, JsonConverter item)
{
inner.Insert(index, item);
count = 0;
}

public bool Remove(JsonConverter item)
{
count = 0;
return inner.Remove(item);
}

public void RemoveAt(int index)
{
inner.RemoveAt(index);
count = 0;
}

public bool Contains(JsonConverter item) =>
inner.Contains(item);

public void CopyTo(JsonConverter[] array, int arrayIndex) =>
inner.CopyTo(array, arrayIndex);

public int IndexOf(JsonConverter item) =>
inner.IndexOf(item);

public IEnumerator<JsonConverter> GetEnumerator() =>
inner.GetEnumerator();

IEnumerator IEnumerable.GetEnumerator() =>
inner.GetEnumerator();
}
2 changes: 2 additions & 0 deletions src/Argon/Linq/JArray.cs
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Expand Up @@ -176,6 +176,8 @@ internal override JToken CloneToken() =>
[RequiresDynamicCode(MiscellaneousUtils.AotWarning)]
public override void WriteTo(JsonWriter writer, params IList<JsonConverter> converters)
{
converters = ConverterListCache.Wrap(converters);

writer.WriteStartArray();

foreach (var value in values)
Expand Down
20 changes: 13 additions & 7 deletions src/Argon/Linq/JContainer.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -409,6 +409,12 @@ internal bool TryAdd(object? content) =>
internal void AddAndSkipParentCheck(JToken token) =>
TryAddInternal(ChildrenTokens.Count, token, true);

// content read from a reader is always a new token with no parent, so it can go straight to
// InsertItem. Add first has to work out whether its argument is a token, a value to wrap or a
// collection to expand, which is several type checks for every token loaded
void AddLoaded(JToken token) =>
InsertItem(ChildrenTokens.Count, token, false);

/// <summary>
/// Adds the specified content as the first children of this <see cref="JToken" />.
/// </summary>
Expand Down Expand Up @@ -518,7 +524,7 @@ void ReadContentFrom(JsonReader r, JsonLoadSettings? settings)
case JsonToken.StartArray:
var a = new JArray();
a.SetLineInfo(lineInfo, settings);
parent.Add(a);
parent.AddLoaded(a);
parent = a;
break;

Expand All @@ -533,7 +539,7 @@ void ReadContentFrom(JsonReader r, JsonLoadSettings? settings)
case JsonToken.StartObject:
var o = new JObject();
o.SetLineInfo(lineInfo, settings);
parent.Add(o);
parent.AddLoaded(o);
parent = o;
break;
case JsonToken.EndObject:
Expand Down Expand Up @@ -567,26 +573,26 @@ void ReadContentFrom(JsonReader r, JsonLoadSettings? settings)
? new JValue(value)
: new JValue(value, knownType);
v.SetLineInfo(lineInfo, settings);
parent.Add(v);
parent.AddLoaded(v);
break;
case JsonToken.Comment:
if (settings is {CommentHandling: CommentHandling.Load})
{
v = JValue.CreateComment((string?) r.GetValue());
v.SetLineInfo(lineInfo, settings);
parent.Add(v);
parent.AddLoaded(v);
}

break;
case JsonToken.Null:
v = JValue.CreateNull();
v.SetLineInfo(lineInfo, settings);
parent.Add(v);
parent.AddLoaded(v);
break;
case JsonToken.Undefined:
v = JValue.CreateUndefined();
v.SetLineInfo(lineInfo, settings);
parent.Add(v);
parent.AddLoaded(v);
break;
case JsonToken.PropertyName:
var property = ReadProperty(r, settings, lineInfo, parent);
Expand All @@ -608,7 +614,7 @@ static JProperty ReadProperty(JsonReader reader, JsonLoadSettings? settings, IJs
{
// JObject.ValidateToken rejects duplicate names, so a separate
// pre-check would hash the name a second time on every property
parentObject.Add(property);
parentObject.AddLoaded(property);
}
catch (ArgumentException)
{
Expand Down
2 changes: 2 additions & 0 deletions src/Argon/Linq/JObject.cs
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Expand Up @@ -363,6 +363,8 @@ public JToken? this[string propertyName]
[RequiresDynamicCode(MiscellaneousUtils.AotWarning)]
public override void WriteTo(JsonWriter writer, params IList<JsonConverter> converters)
{
converters = ConverterListCache.Wrap(converters);

writer.WriteStartObject();

foreach (var property in properties.InnerList)
Expand Down
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