Add char[] buffer to XmlRawWriter. #75411

TrayanZapryanov · 2022-09-11T09:26:47Z

This PR suggest using small char[] buffer in XmlRawWriter and use it for formatting primitive types in it. Then using WriteRaw(char[]) method instead of creating temporary string and WriteRaw(string) method.
Also exposing XmlConverter.TryFormat methods for already exposed ToString(xxx) primitive types, allowing writes to Span destination.
Last change is to expose TryFormat in XsdDateTime and XsdDuration.

This PR will open possibilities in XmlSerializers to use typed methods of XmlWriter instead of always fallback to WriteString one.
Sample optimization

Expose TryFormat methods in XmlConvert and use them in XmlRawWriter. Expose TryFormat in XsdDateTime and XsdDuration.

ghost · 2022-09-11T09:27:01Z

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Issue Details

This PR suggest using small char[] buffer in XmlRawWriter and use it for formatting primitive types in it and then using WriteRaw(char[]) method instead of creating temporary string and using WriteRaw(string).
Also exposing TryFormat methods for already exposed ToString(xxx) primitive types, allowing writes to Span destination.
Last change is to expose TryFormat in XsdDateTime and XsdDuration.

This PR will open possibilities in XmlSerializers to use typed methods of XmlWriter instead of always fallback to WriteString one.

Author:	TrayanZapryanov
Assignees:	-
Labels:	`area-System.Xml`
Milestone:	-

src/libraries/System.Private.Xml/src/System/Xml/Core/XmlRawWriter.cs

TrayanZapryanov · 2022-09-11T09:51:44Z

src/libraries/System.Private.Xml/src/System/Xml/Core/XmlRawWriter.cs

+                _primitivesBuffer = new char[_primitivesBuffer.Length * 2];
+            }
+
+            WriteChars(_primitivesBuffer, 0, charsWritten);


I saw that there is difference between

runtime/src/libraries/System.Private.Xml/src/System/Xml/Core/XmlUtf8RawTextWriter.cs

Line 560 in abb5c34

public override unsafe void WriteChars(char[] buffer, int index, int count)

and

runtime/src/libraries/System.Private.Xml/src/System/Xml/Core/XmlUtf8RawTextWriter.cs

Line 582 in abb5c34

public override unsafe void WriteRaw(char[] buffer, int index, int count)

Which one should be used ?

TrayanZapryanov · 2022-09-11T09:59:13Z

src/libraries/System.Private.Xml/src/System/Xml/Core/XmlRawWriter.cs

@@ -198,7 +265,7 @@ public override void WriteValue(DateTimeOffset value)
        {
            // For compatibility with custom writers, XmlWriter writes DateTimeOffset as DateTime.
            // Our internal writers should use the DateTimeOffset-String conversion from XmlConvert.
-            WriteString(XmlConvert.ToString(value));


This comment seems not relevant as even now it is using

runtime/src/libraries/System.Private.Xml/src/System/Xml/XmlConvert.cs

Line 746 in abb5c34

public static string ToString(DateTimeOffset value)

Maybe it is connected with base code ?

runtime/src/libraries/System.Private.Xml/src/System/Xml/Core/XmlWriter.cs

Line 275 in 8f33fd5

public virtual void WriteValue(DateTimeOffset value)

@krwq Do you know if somebody is changing this Mode ?

runtime/src/libraries/System.Private.Xml/src/System/Xml/Serialization/Xmlcustomformatter.cs

Lines 20 to 34 in 4486805

internal static class XmlCustomFormatter

{

private static DateTimeSerializationSection.DateTimeSerializationMode s_mode;

private static DateTimeSerializationSection.DateTimeSerializationMode Mode

{

get

{

if (s_mode == DateTimeSerializationSection.DateTimeSerializationMode.Default)

{

s_mode = DateTimeSerializationSection.DateTimeSerializationMode.Roundtrip;

}

return s_mode;

}

}

I saw similar code in XmlSerializers and the only way to change is with Reflection and directly manipulating fiedl.

src/libraries/System.Xml.ReaderWriter/ref/System.Xml.ReaderWriter.cs

src/libraries/System.Private.Xml/src/System/Xml/Core/XmlRawWriter.cs

TrayanZapryanov · 2022-09-11T11:38:13Z

src/libraries/System.Private.Xml/src/System/Xml/Core/XmlRawWriter.cs

+                    WriteWithBuffer((char)value, XmlConvert.TryFormat);
+                    break;
+                default:
+                    //Guid is not supported in XmlUntypedConverter.Untyped and throws exception


This limitation is really strange, but we need to adapt XmlValueConverter to allow Guid in it's methods.

Added proposal for this Add WriteValue(Guid/TimeSpan) in System.Xml.XmlWriter

PaulusParssinen · 2022-09-11T15:34:18Z

src/libraries/System.Private.Xml/src/System/Xml/XmlConvert.cs

@@ -1657,5 +1657,241 @@ internal static Exception CreateInvalidNameCharException(string name, int index,
        {
            return CreateException(index == 0 ? SR.Xml_BadStartNameChar : SR.Xml_BadNameChar, XmlException.BuildCharExceptionArgs(name, index), exceptionType, 0, index + 1);
        }
+
+        public static bool TryFormat(bool value, Span<char> destination, out int charsWritten)


I believe this one can do same optimization as in #64782 but with correct casing.

src/libraries/System.Private.Xml/src/System/Xml/Core/XmlRawWriter.cs

TrayanZapryanov · 2022-09-12T08:21:20Z

src/libraries/System.Private.Xml/src/System/Xml/Core/XmlTextWriter.cs

@@ -981,6 +984,117 @@ public override void WriteBinHex(byte[] buffer, int index, int count)
            }
        }

+        // Override in order to handle Xml simple typed values and to pass resolver for QName values
+        public override void WriteValue(object value)


Whole logic for writing with buffer is duplicated in XmlTextWriter and XmlRawWriter.
One suggestion is to create "public" class( this is needed as XmlTextWriter is public) and encapsulate logic in it.
The other is to have some static helper class which works by ref with char[].

Which one do you prefer ?

Duplication logic reduced, but the question still stays open.

TrayanZapryanov · 2022-09-14T06:41:20Z

@krwq, @eiriktsarpalis Is it possible to receive some initial feedback on these changes and to the following ones(changes in serializators to use typed methods instead of converting to string first) ?
Do you see any value in this idea or you expect some problem later that will stop it?
Should I continue with following PRs to change one by one serializers(Reflection, Primitive, IlGen....) based on this or to wait until this one is merged?
I am quite new in proposing changes and will need some guidance if possible.

eiriktsarpalis · 2022-09-14T11:25:58Z

src/libraries/System.Private.Xml/src/System/Xml/Core/XmlRawWriter.cs

@@ -185,7 +184,75 @@ public override void WriteValue(object value)
        {
            ArgumentNullException.ThrowIfNull(value);

-            WriteString(XmlUntypedConverter.Untyped.ToString(value, _resolver));
+            Type sourceType = value.GetType();


This seems to be adding a lot of branching where it previously didn't exist. Could this be done differently? I'm not super familiar with this code, but one thought might be to expose a TryFormat method to XmlUntypedConverter.Untyped.

The code in XmlUntypedConverter.ToString(object) is already similar:
```cs
public override string ToString(object value, IXmlNamespaceResolver? nsResolver)
{
ArgumentNullException.ThrowIfNull(value);

Type sourceType = value.GetType(); if (sourceType == BooleanType) return XmlConvert.ToString((bool)value); if (sourceType == ByteType) return XmlConvert.ToString((byte)value); if (sourceType == ByteArrayType) return Base64BinaryToString((byte[])value); if (sourceType == DateTimeType) return DateTimeToString((DateTime)value); if (sourceType == DateTimeOffsetType) return DateTimeOffsetToString((DateTimeOffset)value); if (sourceType == DecimalType) return XmlConvert.ToString((decimal)value); if (sourceType == DoubleType) return XmlConvert.ToString((double)value); if (sourceType == Int16Type) return XmlConvert.ToString((short)value); if (sourceType == Int32Type) return XmlConvert.ToString((int)value); if (sourceType == Int64Type) return XmlConvert.ToString((long)value); if (sourceType == SByteType) return XmlConvert.ToString((sbyte)value); if (sourceType == SingleType) return XmlConvert.ToString((float)value); if (sourceType == StringType) return ((string)value); if (sourceType == TimeSpanType) return DurationToString((TimeSpan)value); if (sourceType == UInt16Type) return XmlConvert.ToString((ushort)value); if (sourceType == UInt32Type) return XmlConvert.ToString((uint)value); if (sourceType == UInt64Type) return XmlConvert.ToString((ulong)value); if (IsDerivedFrom(sourceType, UriType)) return AnyUriToString((Uri)value); if (sourceType == XmlAtomicValueType) return ((string)((XmlAtomicValue)value).ValueAs(StringType, nsResolver)); if (IsDerivedFrom(sourceType, XmlQualifiedNameType)) return QNameToString((XmlQualifiedName)value, nsResolver); return (string)ChangeTypeWildcardDestination(value, StringType, nsResolver); }

src/libraries/System.Private.Xml/src/System/Xml/Core/XmlTextWriter.cs

TrayanZapryanov · 2022-09-30T10:36:24Z

Closing this in favor of 76436

Add char[] buffer to XmlRawWriter.

bb7581c

Expose TryFormat methods in XmlConvert and use them in XmlRawWriter. Expose TryFormat in XsdDateTime and XsdDuration.

dotnet-issue-labeler bot added the area-System.Xml label Sep 11, 2022

ghost added the community-contribution Indicates that the PR has been added by a community member label Sep 11, 2022

TrayanZapryanov commented Sep 11, 2022

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src/libraries/System.Private.Xml/src/System/Xml/Core/XmlRawWriter.cs Outdated Show resolved Hide resolved

TrayanZapryanov commented Sep 11, 2022

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src/libraries/System.Private.Xml/src/System/Xml/Core/XmlRawWriter.cs Outdated Show resolved Hide resolved

TrayanZapryanov commented Sep 11, 2022

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Add to ref project

2b2aaca

TrayanZapryanov commented Sep 11, 2022

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src/libraries/System.Xml.ReaderWriter/ref/System.Xml.ReaderWriter.cs Outdated Show resolved Hide resolved

TrayanZapryanov added 2 commits September 11, 2022 13:32

Fully qualify names in ref file

613cc41

fix async implementation

297bb20

TrayanZapryanov commented Sep 11, 2022

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src/libraries/System.Private.Xml/src/System/Xml/Core/XmlRawWriter.cs Outdated Show resolved Hide resolved

Replace TypeScope with Type.GetTypeCode

5ee4f9b

TrayanZapryanov commented Sep 11, 2022

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TrayanZapryanov mentioned this pull request Sep 11, 2022

Modify XmlSerializators to use typed XmlWriter.WriteValue method #75415

Closed

PaulusParssinen reviewed Sep 11, 2022

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TrayanZapryanov commented Sep 12, 2022

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src/libraries/System.Private.Xml/src/System/Xml/Core/XmlRawWriter.cs Outdated Show resolved Hide resolved

Add same buffering for XmlTextWriter as raw one

ecc9969

TrayanZapryanov commented Sep 12, 2022

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karelz mentioned this pull request Sep 12, 2022

System.Data.OleDb.Test - timeout and hangs #74488

Open

eiriktsarpalis reviewed Sep 14, 2022

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src/libraries/System.Private.Xml/src/System/Xml/Core/XmlTextWriter.cs Outdated Show resolved Hide resolved

TrayanZapryanov and others added 5 commits September 15, 2022 10:07

Adapt all new TryFormat methods to be internal

47d4def

Remove growing functionallity for primitives buffer

5681aa0

Remove System.Globalization

0efd293

Remove one more new namespace

66ff29e

Merge branch 'dotnet:main' into xml_use_char_buffer_in_xmlwriters

851a749

TrayanZapryanov closed this Sep 30, 2022

TrayanZapryanov deleted the xml_use_char_buffer_in_xmlwriters branch September 30, 2022 10:42

ghost locked as resolved and limited conversation to collaborators Oct 30, 2022

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Add char[] buffer to XmlRawWriter. #75411

Add char[] buffer to XmlRawWriter. #75411

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TrayanZapryanov commented Sep 30, 2022

	internal static class XmlCustomFormatter
	{
	private static DateTimeSerializationSection.DateTimeSerializationMode s_mode;

	private static DateTimeSerializationSection.DateTimeSerializationMode Mode
	{
	get
	{
	if (s_mode == DateTimeSerializationSection.DateTimeSerializationMode.Default)
	{
	s_mode = DateTimeSerializationSection.DateTimeSerializationMode.Roundtrip;
	}
	return s_mode;
	}
	}

Add char[] buffer to XmlRawWriter. #75411

Add char[] buffer to XmlRawWriter. #75411

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