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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.Collections.Generic;
using System.Collections.Immutable;
using System.Threading;
using System.Diagnostics;
using System.Linq;
using Microsoft.CodeAnalysis.Shared.Utilities;
namespace Microsoft.CodeAnalysis.LanguageService;
internal abstract class AbstractFileBannerFacts : IFileBannerFacts
{
// Matches the following:
//
// (whitespace* newline)+
private readonly Matcher<SyntaxTrivia> _oneOrMoreBlankLines;
// Matches the following:
//
// (whitespace* (single-comment|multi-comment) whitespace* newline)+ OneOrMoreBlankLines
private readonly Matcher<SyntaxTrivia> _bannerMatcher;
// Used to match the following:
//
// <start-of-file> (whitespace* (single-comment|multi-comment) whitespace* newline)+ blankLine*
private readonly Matcher<SyntaxTrivia> _fileBannerMatcher;
protected AbstractFileBannerFacts()
{
var whitespace = Matcher.Repeat(
Matcher.Single<SyntaxTrivia>(this.SyntaxFacts.IsWhitespaceTrivia, "\\b"));
var endOfLine = Matcher.Single<SyntaxTrivia>(this.SyntaxFacts.IsEndOfLineTrivia, "\\n");
var singleBlankLine = Matcher.Sequence(whitespace, endOfLine);
var shebangComment = Matcher.Single<SyntaxTrivia>(this.SyntaxFacts.IsShebangDirectiveTrivia, "#!");
var singleLineComment = Matcher.Single<SyntaxTrivia>(this.SyntaxFacts.IsSingleLineCommentTrivia, "//");
var multiLineComment = Matcher.Single<SyntaxTrivia>(this.SyntaxFacts.IsMultiLineCommentTrivia, "/**/");
var singleLineDocumentationComment = Matcher.Single<SyntaxTrivia>(this.SyntaxFacts.IsSingleLineDocCommentTrivia, "///");
var multiLineDocumentationComment = Matcher.Single<SyntaxTrivia>(this.SyntaxFacts.IsMultiLineDocCommentTrivia, "/** */");
var anyCommentMatcher = Matcher.Choice(shebangComment, singleLineComment, multiLineComment, singleLineDocumentationComment, multiLineDocumentationComment);
var commentLine = Matcher.Sequence(whitespace, anyCommentMatcher, whitespace, endOfLine);
_oneOrMoreBlankLines = Matcher.OneOrMore(singleBlankLine);
_bannerMatcher =
Matcher.Sequence(
Matcher.OneOrMore(commentLine),
_oneOrMoreBlankLines);
_fileBannerMatcher =
Matcher.Sequence(
Matcher.OneOrMore(commentLine),
Matcher.Repeat(singleBlankLine));
}
protected abstract ISyntaxFacts SyntaxFacts { get; }
protected abstract IDocumentationCommentService DocumentationCommentService { get; }
public string GetBannerText(SyntaxNode? documentationCommentTriviaSyntax, int bannerLength, CancellationToken cancellationToken)
=> DocumentationCommentService.GetBannerText(documentationCommentTriviaSyntax, bannerLength, cancellationToken);
public ImmutableArray<SyntaxTrivia> GetLeadingBlankLines(SyntaxNode node)
=> GetLeadingBlankLines<SyntaxNode>(node);
public ImmutableArray<SyntaxTrivia> GetLeadingBlankLines<TSyntaxNode>(TSyntaxNode node)
where TSyntaxNode : SyntaxNode
{
GetNodeWithoutLeadingBlankLines(node, out var blankLines);
return blankLines;
}
public TSyntaxNode GetNodeWithoutLeadingBlankLines<TSyntaxNode>(TSyntaxNode node)
where TSyntaxNode : SyntaxNode
{
return GetNodeWithoutLeadingBlankLines(node, out _);
}
public TSyntaxNode GetNodeWithoutLeadingBlankLines<TSyntaxNode>(
TSyntaxNode node, out ImmutableArray<SyntaxTrivia> strippedTrivia)
where TSyntaxNode : SyntaxNode
{
var leadingTriviaToKeep = new List<SyntaxTrivia>(node.GetLeadingTrivia());
var index = 0;
_oneOrMoreBlankLines.TryMatch(leadingTriviaToKeep, ref index);
strippedTrivia = leadingTriviaToKeep.Take(index).ToImmutableArray();
return node.WithLeadingTrivia(leadingTriviaToKeep.Skip(index));
}
public ImmutableArray<SyntaxTrivia> GetLeadingBannerAndPreprocessorDirectives<TSyntaxNode>(TSyntaxNode node)
where TSyntaxNode : SyntaxNode
{
GetNodeWithoutLeadingBannerAndPreprocessorDirectives(node, out var leadingTrivia);
return leadingTrivia;
}
public TSyntaxNode GetNodeWithoutLeadingBannerAndPreprocessorDirectives<TSyntaxNode>(
TSyntaxNode node)
where TSyntaxNode : SyntaxNode
{
return GetNodeWithoutLeadingBannerAndPreprocessorDirectives(node, out _);
}
public TSyntaxNode GetNodeWithoutLeadingBannerAndPreprocessorDirectives<TSyntaxNode>(
TSyntaxNode node, out ImmutableArray<SyntaxTrivia> strippedTrivia)
where TSyntaxNode : SyntaxNode
{
var leadingTrivia = node.GetLeadingTrivia();
// Rules for stripping trivia:
// 1) If there is a pp directive, then it (and all preceding trivia) *must* be stripped.
// This rule supersedes all other rules.
// 2) If there is a doc comment, it cannot be stripped. Even if there is a doc comment,
// followed by 5 new lines, then the doc comment still must stay with the node. This
// rule does *not* supersede rule 1.
// 3) Single line comments in a group (i.e. with no blank lines between them) belong to
// the node *iff* there is no blank line between it and the following trivia.
List<SyntaxTrivia> leadingTriviaToStrip, leadingTriviaToKeep;
var ppIndex = -1;
for (var i = leadingTrivia.Count - 1; i >= 0; i--)
{
if (this.SyntaxFacts.IsPreprocessorDirective(leadingTrivia[i]))
{
ppIndex = i;
break;
}
}
if (ppIndex != -1)
{
// We have a pp directive. it (and all previous trivia) must be stripped.
leadingTriviaToStrip = new List<SyntaxTrivia>(leadingTrivia.Take(ppIndex + 1));
leadingTriviaToKeep = new List<SyntaxTrivia>(leadingTrivia.Skip(ppIndex + 1));
}
else
{
leadingTriviaToKeep = new List<SyntaxTrivia>(leadingTrivia);
leadingTriviaToStrip = [];
}
// Now, consume as many banners as we can. s_fileBannerMatcher will only be matched at
// the start of the file.
var index = 0;
while (
_oneOrMoreBlankLines.TryMatch(leadingTriviaToKeep, ref index) ||
_bannerMatcher.TryMatch(leadingTriviaToKeep, ref index) ||
(node.FullSpan.Start == 0 && _fileBannerMatcher.TryMatch(leadingTriviaToKeep, ref index)))
{
}
leadingTriviaToStrip.AddRange(leadingTriviaToKeep.Take(index));
strippedTrivia = [.. leadingTriviaToStrip];
return node.WithLeadingTrivia(leadingTriviaToKeep.Skip(index));
}
public ImmutableArray<SyntaxTrivia> GetFileBanner(SyntaxNode root)
{
Debug.Assert(root.FullSpan.Start == 0);
return GetFileBanner(root.GetFirstToken(includeZeroWidth: true));
}
public ImmutableArray<SyntaxTrivia> GetFileBanner(SyntaxToken firstToken)
{
Debug.Assert(firstToken.FullSpan.Start == 0);
var leadingTrivia = firstToken.LeadingTrivia;
var index = 0;
_fileBannerMatcher.TryMatch(leadingTrivia.ToList(), ref index);
return ImmutableArray.CreateRange(leadingTrivia.Take(index));
}
}
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