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Merged
YuliiaKovalova merged 5 commits into from
Jul 2, 2025
Merged

Dev/erarndt/span based string builder #12100

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b34eae3
Avoid intermediate string allocations by updating SpanBasedStringBuilder
Erarndt May 16, 2025
0478744
Merge branch 'main' of https://github.com/dotnet/msbuild into dev/era…
Erarndt Jun 18, 2025
68c79b7
Merge branch 'main' of https://github.com/dotnet/msbuild into dev/era…
Erarndt Jul 1, 2025
9dbf50c
Cleanup
Erarndt Jul 1, 2025
264e158
Consolidate implementation
Erarndt Jul 1, 2025
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28 changes: 11 additions & 17 deletions src/Build/Evaluation/Expander.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -280,9 +280,6 @@ private void FlushFirstValueIfNeeded()
/// Enabled by ExpanderOptions.Truncate.
/// </summary>
private const int ItemLimitPerExpansion = 3;
private static readonly char[] s_singleQuoteChar = { '\'' };
private static readonly char[] s_backtickChar = { '`' };
private static readonly char[] s_doubleQuoteChar = { '"' };

/// <summary>
/// The CultureInfo from the invariant culture. Used to avoid allocations for
Expand Down Expand Up @@ -785,37 +782,34 @@ private static void AddArgument(List<string> arguments, SpanBasedStringBuilder a
// we reached the end of an argument, add the builder's final result
// to our arguments.
argumentBuilder.Trim();
string argValue = argumentBuilder.ToString();

// We support passing of null through the argument constant value null
if (String.Equals("null", argValue, StringComparison.OrdinalIgnoreCase))
if (argumentBuilder.Equals("null", StringComparison.OrdinalIgnoreCase))
{
arguments.Add(null);
}
else
{
if (argValue.Length > 0)
if (argumentBuilder.Length > 0)
{
if (argValue[0] == '\'' && argValue[argValue.Length - 1] == '\'')
if (argumentBuilder[0] == '\'' && argumentBuilder[argumentBuilder.Length - 1] == '\'')
{
arguments.Add(argValue.Trim(s_singleQuoteChar));
argumentBuilder.Trim('\'');
}
else if (argValue[0] == '`' && argValue[argValue.Length - 1] == '`')
else if (argumentBuilder[0] == '`' && argumentBuilder[argumentBuilder.Length - 1] == '`')
{
arguments.Add(argValue.Trim(s_backtickChar));
argumentBuilder.Trim('`');
}
else if (argValue[0] == '"' && argValue[argValue.Length - 1] == '"')
else if (argumentBuilder[0] == '"' && argumentBuilder[argumentBuilder.Length - 1] == '"')
{
arguments.Add(argValue.Trim(s_doubleQuoteChar));
}
else
{
arguments.Add(argValue);
argumentBuilder.Trim('"');
}

arguments.Add(argumentBuilder.ToString());
}
else
{
arguments.Add(argValue);
arguments.Add(string.Empty);
}
}
}
Expand Down
121 changes: 114 additions & 7 deletions src/StringTools/SpanBasedStringBuilder.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -120,7 +120,48 @@ public SpanBasedStringBuilder(int capacity = 4)
/// </summary>
public int Capacity => _spans.Capacity;

public char this[int index]
{
get
{
if (index < 0 || index >= Length)
{
throw new ArgumentOutOfRangeException(nameof(index));
}

int adjustedIndex = index;
foreach (ReadOnlyMemory<char> span in _spans)
{
if (adjustedIndex < span.Length)
{
return span.Span[adjustedIndex];
}
else
{
adjustedIndex -= span.Length;
}
}

// Should never reach here if Length is correct
throw new IndexOutOfRangeException();
}
}

/// <summary>
/// Creates a new enumerator for enumerating characters in this string. Does not allocate.
/// </summary>
/// <returns>The enumerator.</returns>
public Enumerator GetEnumerator()
{
return new Enumerator(_spans);
}

public bool Equals(ReadOnlySpan<char> other)
{
return Equals(other, StringComparison.Ordinal);
}

public bool Equals(ReadOnlySpan<char> other, StringComparison comparison)
{
if (_spans.Count == 0 && other.IsEmpty)
{
Expand All @@ -135,7 +176,7 @@ public bool Equals(ReadOnlySpan<char> other)
int otherIndex = 0;
foreach (ReadOnlyMemory<char> internalSpan in _spans)
{
if (!MemoryExtensions.Equals(other.Slice(otherIndex, internalSpan.Length), internalSpan.Span, StringComparison.Ordinal))
if (!MemoryExtensions.Equals(other.Slice(otherIndex, internalSpan.Length), internalSpan.Span, comparison))
{
return false;
}
Expand All @@ -146,13 +187,29 @@ public bool Equals(ReadOnlySpan<char> other)
return true;
}

/// <summary>
/// Creates a new enumerator for enumerating characters in this string. Does not allocate.
/// </summary>
/// <returns>The enumerator.</returns>
public Enumerator GetEnumerator()
public bool Equals(string other)
{
return new Enumerator(_spans);
return Equals(other, StringComparison.Ordinal);
}

public bool Equals(string other, StringComparison comparison)
{
if (other.Length != Length)
{
return false;
}

int index = 0;
ReadOnlySpan<char> inputSpan = other.AsSpan();
foreach (ReadOnlyMemory<char> memory in _spans)
{
if (!MemoryExtensions.Equals(memory.Span, inputSpan.Slice(index, memory.Length), comparison))
{
return false;
}
}

return true;
}

/// <summary>
Expand Down Expand Up @@ -252,6 +309,28 @@ public void TrimStart()
}
}

public void TrimStart(char c)
{
for (int spanIdx = 0; spanIdx < _spans.Count; spanIdx++)
{
ReadOnlySpan<char> span = _spans[spanIdx].Span;
int i = 0;
while (i < span.Length && span[i] == c)
{
i++;
}
if (i > 0)
{
_spans[spanIdx] = _spans[spanIdx].Slice(i);
Length -= i;
}
if (!_spans[spanIdx].IsEmpty)
{
return;
}
}
}

/// <summary>
/// Removes trailing white-space characters from the string.
/// </summary>
Expand All @@ -277,6 +356,28 @@ public void TrimEnd()
}
}

public void TrimEnd(char c)
{
for (int spanIdx = _spans.Count - 1; spanIdx >= 0; spanIdx--)
{
ReadOnlySpan<char> span = _spans[spanIdx].Span;
int i = span.Length - 1;
while (i >= 0 && span[i] == c)
{
i--;
}
if (i + 1 < span.Length)
{
_spans[spanIdx] = _spans[spanIdx].Slice(0, i + 1);
Length -= span.Length - (i + 1);
}
if (!_spans[spanIdx].IsEmpty)
{
return;
}
}
}

/// <summary>
/// Removes leading and trailing white-space characters from the string.
/// </summary>
Expand All @@ -286,6 +387,12 @@ public void Trim()
TrimEnd();
}

public void Trim(char c)
{
TrimStart(c);
TrimEnd(c);
}

/// <summary>
/// Clears this instance making it represent an empty string.
/// </summary>
Expand Down
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