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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.Collections.Generic;
using System.Collections.Immutable;
using System.Composition;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.CodeActions;
using Microsoft.CodeAnalysis.CodeFixes;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Diagnostics;
using Microsoft.CodeAnalysis.Host.Mef;
using Microsoft.CodeAnalysis.PooledObjects;
using Microsoft.CodeAnalysis.Shared.Extensions;
namespace Microsoft.CodeAnalysis.CSharp.NewLines.ConstructorInitializerPlacement;
[ExportCodeFixProvider(LanguageNames.CSharp, Name = PredefinedCodeFixProviderNames.ConstructorInitializerPlacement), Shared]
[method: ImportingConstructor]
[method: Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
internal sealed class ConstructorInitializerPlacementCodeFixProvider() : CodeFixProvider
{
public override ImmutableArray<string> FixableDiagnosticIds
=> [IDEDiagnosticIds.ConstructorInitializerPlacementDiagnosticId];
public override Task RegisterCodeFixesAsync(CodeFixContext context)
{
var document = context.Document;
var diagnostic = context.Diagnostics.First();
context.RegisterCodeFix(
CodeAction.Create(
CSharpCodeFixesResources.Place_token_on_following_line,
c => UpdateDocumentAsync(document, [diagnostic], c),
nameof(CSharpCodeFixesResources.Place_token_on_following_line)),
context.Diagnostics);
return Task.CompletedTask;
}
private static async Task<Document> UpdateDocumentAsync(
Document document, ImmutableArray<Diagnostic> diagnostics, CancellationToken cancellationToken)
{
var text = await document.GetValueTextAsync(cancellationToken).ConfigureAwait(false);
var root = await document.GetRequiredSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
using var _ = PooledDictionary<SyntaxToken, SyntaxToken>.GetInstance(out var replacementMap);
foreach (var diagnostic in diagnostics)
{
var initializer = (ConstructorInitializerSyntax)diagnostic.AdditionalLocations[0].FindNode(getInnermostNodeForTie: true, cancellationToken);
var colonToken = initializer.ColonToken;
var thisBaseKeyword = initializer.ThisOrBaseKeyword;
var parenToken = colonToken.GetPreviousToken();
if (text.AreOnSameLine(parenToken, colonToken))
{
// something like:
//
// public C() :
// base()
//
// Move the trivia from the : to the preceding ) and move the trivia on 'base' to the colon, and
// add a space after it.
MoveTriviaWhenOnSameLine(replacementMap, colonToken, thisBaseKeyword);
}
else
{
// something like:
//
// public C()
// :
// base()
//
// Just add a space after the colon, and remove all leading trivia from this/base
replacementMap[colonToken] = colonToken.WithLeadingTrivia(colonToken.LeadingTrivia.AddRange(colonToken.TrailingTrivia).AddRange(thisBaseKeyword.LeadingTrivia))
.WithTrailingTrivia(SyntaxFactory.Space);
replacementMap[thisBaseKeyword] = thisBaseKeyword.WithoutLeadingTrivia();
}
}
var newRoot = root.ReplaceTokens(replacementMap.Keys, (original, _) => replacementMap[original]);
return document.WithSyntaxRoot(newRoot);
}
private static void MoveTriviaWhenOnSameLine(
Dictionary<SyntaxToken, SyntaxToken> replacementMap, SyntaxToken colonToken, SyntaxToken thisBaseKeyword)
{
// colonToken has the unnecessary newline. Move all of it's trivia to the previous token so nothing belongs to it.
var closeParen = colonToken.GetPreviousToken();
replacementMap[closeParen] = ComputeNewCloseParen(colonToken, closeParen);
// Now, take all the trivia from the this/base keyword, and move before the colon, and add a space after it
// this will place it properly before the this/base keyword.
replacementMap[colonToken] = colonToken.WithLeadingTrivia(thisBaseKeyword.LeadingTrivia).WithTrailingTrivia(SyntaxFactory.Space);
// Finally, remove all leading trivia from the this/base keyword. It was moved to the colon
replacementMap[thisBaseKeyword] = thisBaseKeyword.WithoutLeadingTrivia();
static SyntaxToken ComputeNewCloseParen(SyntaxToken colonToken, SyntaxToken previousToken)
{
var allColonTrivia = colonToken.LeadingTrivia.AddRange(colonToken.TrailingTrivia);
return previousToken.TrailingTrivia.All(t => t.Kind() == SyntaxKind.WhitespaceTrivia)
? previousToken.WithTrailingTrivia(allColonTrivia)
: previousToken.WithAppendedTrailingTrivia(allColonTrivia);
}
}
public override FixAllProvider? GetFixAllProvider()
=> FixAllProvider.Create(async (context, document, diagnostics) => await UpdateDocumentAsync(document, diagnostics, context.CancellationToken).ConfigureAwait(false));
}
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