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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using System;
using System.Composition;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.BraceMatching;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Host.Mef;
using Microsoft.CodeAnalysis.Shared.Extensions;
using Microsoft.CodeAnalysis.Text;
namespace Microsoft.CodeAnalysis.CSharp.BraceMatching;
[ExportBraceMatcher(LanguageNames.CSharp), Shared]
internal class StringLiteralBraceMatcher : IBraceMatcher
{
[ImportingConstructor]
[Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
public StringLiteralBraceMatcher()
{
}
public async Task<BraceMatchingResult?> FindBracesAsync(Document document, int position, BraceMatchingOptions options, CancellationToken cancellationToken)
{
var root = await document.GetRequiredSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
var token = root.FindToken(position);
if (!token.ContainsDiagnostics)
{
if (token.IsKind(SyntaxKind.StringLiteralToken))
{
return GetSimpleStringBraceMatchingResult(token, endTokenLength: 1);
}
else if (token.IsKind(SyntaxKind.Utf8StringLiteralToken))
{
return GetSimpleStringBraceMatchingResult(token, endTokenLength: 3);
}
else if (token.Kind() is SyntaxKind.InterpolatedStringStartToken or SyntaxKind.InterpolatedVerbatimStringStartToken)
{
if (token.Parent is InterpolatedStringExpressionSyntax interpolatedString)
{
return new BraceMatchingResult(token.Span, interpolatedString.StringEndToken.Span);
}
}
else if (token.IsKind(SyntaxKind.InterpolatedStringEndToken))
{
if (token.Parent is InterpolatedStringExpressionSyntax interpolatedString)
{
return new BraceMatchingResult(interpolatedString.StringStartToken.Span, token.Span);
}
}
}
return null;
}
private static BraceMatchingResult GetSimpleStringBraceMatchingResult(SyntaxToken token, int endTokenLength)
{
if (token.IsVerbatimStringLiteral())
{
return new BraceMatchingResult(
new TextSpan(token.SpanStart, 2),
new TextSpan(token.Span.End - endTokenLength, endTokenLength));
}
else
{
return new BraceMatchingResult(
new TextSpan(token.SpanStart, 1),
new TextSpan(token.Span.End - endTokenLength, endTokenLength));
}
}
}
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