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Avoid allocation in PathString.Add #28855

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merged 1 commit into from
Dec 28, 2020
Merged

Avoid allocation in PathString.Add #28855

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42 changes: 15 additions & 27 deletions src/Http/Http.Abstractions/src/PathString.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,7 @@ namespace Microsoft.AspNetCore.Http
/// <summary>
/// Represents the empty path. This field is read-only.
/// </summary>
public static readonly PathString Empty = new PathString(string.Empty);
public static readonly PathString Empty = new(string.Empty);

/// <summary>
/// Initialize the path string with a given value. This value must be in unescaped format. Use
Expand Down Expand Up @@ -103,11 +103,7 @@ private static string ToEscapedUriComponent(string value, int i)
if (requiresEscaping)
{
// the current segment requires escape
if (buffer == null)
{
buffer = new StringBuilder(value.Length * 3);
}

buffer ??= new StringBuilder(value.Length * 3);
buffer.Append(Uri.EscapeDataString(value.Substring(start, count)));

requiresEscaping = false;
Expand All @@ -131,11 +127,7 @@ private static string ToEscapedUriComponent(string value, int i)
if (!requiresEscaping)
{
// the current segment doesn't require escape
if (buffer == null)
{
buffer = new StringBuilder(value.Length * 3);
}

buffer ??= new StringBuilder(value.Length * 3);
buffer.Append(value, start, count);

requiresEscaping = true;
Expand All @@ -156,10 +148,7 @@ private static string ToEscapedUriComponent(string value, int i)
{
if (count > 0)
{
if (buffer == null)
{
buffer = new StringBuilder(value.Length * 3);
}
buffer ??= new StringBuilder(value.Length * 3);

if (requiresEscaping)
{
Expand Down Expand Up @@ -259,7 +248,7 @@ public bool StartsWithSegments(PathString other, StringComparison comparisonType
{
if (value1.Length == value2.Length || value1[value2.Length] == '/')
{
remaining = new PathString(value1.Substring(value2.Length));
remaining = new PathString(value1[value2.Length..]);
return true;
}
}
Expand Down Expand Up @@ -298,7 +287,7 @@ public bool StartsWithSegments(PathString other, StringComparison comparisonType
if (value1.Length == value2.Length || value1[value2.Length] == '/')
{
matched = new PathString(value1.Substring(0, value2.Length));
remaining = new PathString(value1.Substring(value2.Length));
remaining = new PathString(value1[value2.Length..]);
return true;
}
}
Expand All @@ -315,11 +304,12 @@ public PathString Add(PathString other)
{
if (HasValue &&
other.HasValue &&
Value![Value.Length - 1] == '/')
Value[^1] == '/')
{
// If the path string has a trailing slash and the other string has a leading slash, we need
// to trim one of them.
return new PathString(Value + other.Value!.Substring(1));
var combined = string.Concat(Value.AsSpan(), other.Value.AsSpan(1));
return new PathString(combined);
}

return new PathString(Value + other.Value);
Expand Down Expand Up @@ -366,11 +356,11 @@ public bool Equals(PathString other, StringComparison comparisonType)
/// <returns>True if both PathString values are equal</returns>
public override bool Equals(object? obj)
{
if (ReferenceEquals(null, obj))
if (obj is null)
{
return !HasValue;
}
return obj is PathString && Equals((PathString)obj);
return obj is PathString pathString && Equals(pathString);
}

/// <summary>
Expand Down Expand Up @@ -471,18 +461,16 @@ internal static PathString ConvertFromString(string? s)
internal sealed class PathStringConverter : TypeConverter
{
public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
=> sourceType == typeof(string)
? true
: base.CanConvertFrom(context, sourceType);
=> sourceType == typeof(string) || base.CanConvertFrom(context, sourceType);

public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
=> value is string
? PathString.ConvertFromString((string)value)
=> value is string @string
? PathString.ConvertFromString(@string)
: base.ConvertFrom(context, culture, value);

public override object ConvertTo(ITypeDescriptorContext context,
CultureInfo culture, object value, Type destinationType)
=> destinationType == typeof(string)
=> destinationType == typeof(string)
? value.ToString() ?? string.Empty
: base.ConvertTo(context, culture, value, destinationType);
}
Expand Down