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perf: use ValueListBuilder for PrivatePrintLeadingTrivia #1532

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perf: use ValueListBuilder for PrivatePrintLeadingTrivia #1532

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9c0994b
perf: use `ValueListBuilder` for `PrivatePrintLeadingTrivia`
TimothyMakkison Mar 9, 2025
75b2804
perf: change `RemoveAt` to set `Contents` to `Doc.Null`
TimothyMakkison Mar 16, 2025
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10 changes: 10 additions & 0 deletions Src/CSharpier/DocTypes/Doc.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -56,6 +56,16 @@ public static Doc Concat(List<Doc> contents) =>

public static Doc Concat(params Doc[] contents) => new Concat(contents);

public static Doc Concat(ref ValueListBuilder<Doc> contents)
{
return contents.Length switch
{
0 => Null,
1 => contents[0],
_ => Concat(contents.AsSpan().ToArray()),
};
}

public static Doc Join(Doc separator, IEnumerable<Doc> enumerable)
{
var docs = new List<Doc>();
Expand Down
9 changes: 7 additions & 2 deletions Src/CSharpier/SyntaxPrinter/SyntaxNodePrinters/CompilationUnit.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -25,9 +25,14 @@ public static Doc Print(CompilationUnitSyntax node, PrintingContext context)
&& previousList.Contents[^2] is HardLine
)
{
while (list.Contents[0] is HardLine { SkipBreakIfFirstInGroup: true })
for (
var i = 0;
i < list.Contents.Count
&& list.Contents[i] is HardLine { SkipBreakIfFirstInGroup: true };
i++
)
{
list.Contents.RemoveAt(0);
list.Contents[i] = Doc.Null;
}

docs.Add(finalTrivia);
Expand Down
42 changes: 21 additions & 21 deletions Src/CSharpier/SyntaxPrinter/Token.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -233,7 +233,7 @@ private static Doc PrivatePrintLeadingTrivia(
return Doc.Null;
}

var docs = new List<Doc>();
var docs = new ValueListBuilder<Doc>([null, null, null, null, null, null, null, null]);

// we don't print any new lines until we run into a comment or directive
// the PrintExtraNewLines method takes care of printing the initial new lines for a given node
Expand All @@ -246,28 +246,28 @@ private static Doc PrivatePrintLeadingTrivia(

if (printNewLines && kind == SyntaxKind.EndOfLineTrivia)
{
if (docs.Count > 0 && docs[^1] == Doc.HardLineSkipBreakIfFirstInGroup)
if (docs.Length > 0 && docs[^1] == Doc.HardLineSkipBreakIfFirstInGroup)
{
printNewLines = false;
}

if (
!(
docs.Count > 1
docs.Length > 1
&& docs[^1] == Doc.HardLineSkipBreakIfFirstInGroup
&& docs[^2] is LeadingComment { Type: CommentType.SingleLine }
)
)
{
docs.Add(Doc.HardLineSkipBreakIfFirstInGroup);
docs.Append(Doc.HardLineSkipBreakIfFirstInGroup);
}
}
if (kind is not (SyntaxKind.EndOfLineTrivia or SyntaxKind.WhitespaceTrivia))
{
printNewLines = true;
}

void AddLeadingComment(CommentType commentType)
void AddLeadingComment(CommentType commentType, ref ValueListBuilder<Doc> docs)
{
var comment = trivia.ToFullString().TrimEnd('\n', '\r');
if (
Expand All @@ -279,43 +279,43 @@ void AddLeadingComment(CommentType commentType)
comment = leadingTrivia[x - 1] + comment;
}

docs.Add(Doc.LeadingComment(comment, commentType));
docs.Append(Doc.LeadingComment(comment, commentType));
}

if (IsSingleLineComment(kind))
{
AddLeadingComment(CommentType.SingleLine);
docs.Add(
AddLeadingComment(CommentType.SingleLine, ref docs);
docs.Append(
kind == SyntaxKind.SingleLineDocumentationCommentTrivia
? Doc.HardLineSkipBreakIfFirstInGroup
: Doc.Null
);
}
else if (IsMultiLineComment(kind))
{
AddLeadingComment(CommentType.MultiLine);
AddLeadingComment(CommentType.MultiLine, ref docs);
}
else if (kind == SyntaxKind.DisabledTextTrivia)
{
docs.Add(Doc.Trim, trivia.ToString());
docs.Append(Doc.Trim, trivia.ToString());
}
else if (IsRegion(kind))
{
var triviaText = trivia.ToString();
docs.Add(Doc.HardLineIfNoPreviousLine);
docs.Add(Doc.Trim);
docs.Add(
docs.Append(Doc.HardLineIfNoPreviousLine);
docs.Append(Doc.Trim);
docs.Append(
kind == SyntaxKind.RegionDirectiveTrivia
? Doc.BeginRegion(triviaText)
: Doc.EndRegion(triviaText)
);
docs.Add(Doc.HardLine);
docs.Append(Doc.HardLine);
}
else if (trivia.IsDirective)
{
var triviaText = trivia.ToString();

docs.Add(
docs.Append(
// adding two of these to ensure we get a new line when a directive follows a trailing comment
Doc.HardLineIfNoPreviousLineSkipBreakIfFirstInGroup,
Doc.HardLineIfNoPreviousLineSkipBreakIfFirstInGroup,
Expand All @@ -333,16 +333,16 @@ void AddLeadingComment(CommentType commentType)
)
{
x++;
docs.Add(Doc.HardLineSkipBreakIfFirstInGroup);
docs.Append(Doc.HardLineSkipBreakIfFirstInGroup);
}
printNewLines = false;
}
}
}

while (skipLastHardline && docs.Count != 0 && docs.Last() is HardLine or NullDoc)
while (skipLastHardline && docs.Length != 0 && docs[^1] is HardLine or NullDoc)
{
docs.RemoveAt(docs.Count - 1);
docs.Pop();
}

if (context.State.NextTriviaNeedsLine)
Expand All @@ -353,7 +353,7 @@ void AddLeadingComment(CommentType commentType)
}
else
{
var index = docs.Count - 1;
var index = docs.Length - 1;
while (
index >= 0
&& (docs[index] is HardLine or LeadingComment || docs[index] == Doc.Null)
Expand All @@ -364,7 +364,7 @@ void AddLeadingComment(CommentType commentType)
// this handles an edge case where we get here but already added the line
// it relates to the fact that single line comments include new line directives
if (
index + 2 >= docs.Count
index + 2 >= docs.Length
|| !(docs[index + 1] is HardLine && docs[index + 2] is HardLine)
)
{
Expand All @@ -374,7 +374,7 @@ void AddLeadingComment(CommentType commentType)
context.State.NextTriviaNeedsLine = false;
}

return docs.Count > 0 ? Doc.Concat(docs) : Doc.Null;
return Doc.Concat(ref docs);
}

private static bool IsSingleLineComment(SyntaxKind kind) =>
Expand Down
22 changes: 14 additions & 8 deletions Src/CSharpier/Utilities/ValueListBuilder.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -89,18 +89,17 @@ private void AppendMultiChar(scoped ReadOnlySpan<T> source)
_pos += source.Length;
}

public void Insert(int index, scoped ReadOnlySpan<T> source)
public void Insert(int index, T item)
{
Debug.Assert(index == 0, "Implementation currently only supports index == 0");

if ((uint)(_pos + source.Length) > (uint)_span.Length)
int pos = _pos;
if ((uint)pos >= (uint)_span.Length)
{
Grow(source.Length);
Grow(1);
}

_span.Slice(0, _pos).CopyTo(_span.Slice(source.Length));
source.CopyTo(_span);
_pos += source.Length;
_span.Slice(index, _pos - index).CopyTo(_span.Slice(index + 1));
_span[index] = item;
_pos += 1;
}

[MethodImpl(MethodImplOptions.AggressiveInlining)]
Expand Down Expand Up @@ -141,6 +140,13 @@ private void AddWithResize(T item)
_pos = pos + 1;
}

[MethodImpl(MethodImplOptions.AggressiveInlining)]
public T Pop()
{
_pos--;
return _span[_pos];
}

public ReadOnlySpan<T> AsSpan()
{
return _span.Slice(0, _pos);
Expand Down