File: src\Workspaces\SharedUtilitiesAndExtensions\Compiler\VisualBasic\Formatting\Engine\Trivia\VisualBasicTriviaFormatter.vb
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Project: src\src\RoslynAnalyzers\Roslyn.Diagnostics.Analyzers\VisualBasic\Roslyn.Diagnostics.VisualBasic.Analyzers.vbproj (Roslyn.Diagnostics.VisualBasic.Analyzers)
' 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.
 
Imports System.Threading
Imports Microsoft.CodeAnalysis
Imports Microsoft.CodeAnalysis.Formatting
Imports Microsoft.CodeAnalysis.PooledObjects
Imports Microsoft.CodeAnalysis.Text
Imports Microsoft.CodeAnalysis.VisualBasic.Syntax
 
Namespace Microsoft.CodeAnalysis.VisualBasic.Formatting
    Partial Friend Class VisualBasicTriviaFormatter
        Inherits AbstractTriviaFormatter
 
        Private ReadOnly _lineContinuationTrivia As SyntaxTrivia = SyntaxFactory.LineContinuationTrivia("_")
        Private _newLine As SyntaxTrivia
 
        Private _succeeded As Boolean = True
 
        Public Sub New(context As FormattingContext,
                       formattingRules As ChainedFormattingRules,
                       token1 As SyntaxToken,
                       token2 As SyntaxToken,
                       originalString As String,
                       lineBreaks As Integer,
                       spaces As Integer)
            MyBase.New(context, formattingRules, token1, token2, originalString, lineBreaks, spaces)
        End Sub
 
        Protected Overrides Function Succeeded() As Boolean
            Return _succeeded
        End Function
 
        Protected Overrides Function IsWhitespace(trivia As SyntaxTrivia) As Boolean
            Return trivia.RawKind = SyntaxKind.WhitespaceTrivia
        End Function
 
        Protected Overrides Function IsEndOfLine(trivia As SyntaxTrivia) As Boolean
            Return trivia.RawKind = SyntaxKind.EndOfLineTrivia
        End Function
 
        Protected Overrides Function IsWhitespace(ch As Char) As Boolean
            Return Char.IsWhiteSpace(ch) OrElse SyntaxFacts.IsWhitespace(ch)
        End Function
 
        Protected Overrides Function IsNewLine(ch As Char) As Boolean
            Return SyntaxFacts.IsNewLine(ch)
        End Function
 
        Protected Overrides Function CreateWhitespace(text As String) As SyntaxTrivia
            Return SyntaxFactory.Whitespace(text)
        End Function
 
        Protected Overrides Function CreateEndOfLine() As SyntaxTrivia
            If _newLine = Nothing Then
                _newLine = SyntaxFactory.EndOfLine(Context.Options.NewLine)
            End If
 
            Return _newLine
        End Function
 
        Protected Overrides Function GetLineColumnRuleBetween(trivia1 As SyntaxTrivia, existingWhitespaceBetween As LineColumnDelta, implicitLineBreak As Boolean, trivia2 As SyntaxTrivia, cancellationToken As CancellationToken) As LineColumnRule
 
            ' line continuation
            If trivia2.Kind = SyntaxKind.LineContinuationTrivia Then
                Return LineColumnRule.ForceSpacesOrUseFollowIndentation(indentation:=0)
            End If
 
            If IsStartOrEndOfFile(trivia1, trivia2) Then
                Return LineColumnRule.PreserveLinesWithAbsoluteIndentation(lines:=0, indentation:=0)
            End If
 
            ' :: case
            If trivia1.Kind = SyntaxKind.ColonTrivia AndAlso
               trivia2.Kind = SyntaxKind.ColonTrivia Then
                Return LineColumnRule.ForceSpacesOrUseDefaultIndentation(spaces:=0)
            End If
 
            ' : after : token
            If Token1.Kind = SyntaxKind.ColonToken AndAlso trivia2.Kind = SyntaxKind.ColonTrivia Then
                Return LineColumnRule.ForceSpacesOrUseDefaultIndentation(spaces:=0)
            End If
 
            ' : [token]
            If trivia1.Kind = SyntaxKind.ColonTrivia AndAlso trivia2.Kind = 0 AndAlso
               Token2.Kind <> SyntaxKind.None AndAlso Token2.Kind <> SyntaxKind.EndOfFileToken Then
                Return LineColumnRule.ForceSpacesOrUseDefaultIndentation(spaces:=1)
            End If
 
            If trivia1.Kind = SyntaxKind.ColonTrivia OrElse
               trivia2.Kind = SyntaxKind.ColonTrivia Then
                Return LineColumnRule.ForceSpacesOrUseDefaultIndentation(spaces:=1)
            End If
 
            ' [trivia] [whitespace] [token] case
            If trivia2.Kind = SyntaxKind.None Then
                Dim insertNewLine = Me.FormattingRules.GetAdjustNewLinesOperation(Me.Token1, Me.Token2) IsNot Nothing
 
                If insertNewLine Then
                    Return LineColumnRule.PreserveLinesWithDefaultIndentation(lines:=0)
                End If
 
                Return LineColumnRule.PreserveLinesWithGivenIndentation(lines:=0)
            End If
 
            ' preprocessor case
            If SyntaxFacts.IsPreprocessorDirective(trivia2.Kind) Then
                ' if this is the first line of the file, don't put extra line 1
                Dim firstLine = (trivia1.RawKind = SyntaxKind.None) AndAlso (Token1.Kind = SyntaxKind.None)
 
                Dim lines = If(firstLine, 0, 1)
                Return LineColumnRule.PreserveLinesWithAbsoluteIndentation(lines, indentation:=0)
            End If
 
            ' comment before a Case Statement case
            If trivia2.Kind = SyntaxKind.CommentTrivia AndAlso
               Token2.Kind = SyntaxKind.CaseKeyword AndAlso Token2.Parent.IsKind(SyntaxKind.CaseStatement) Then
                Return LineColumnRule.Preserve
            End If
 
            ' comment case
            If trivia2.Kind = SyntaxKind.CommentTrivia OrElse
               trivia2.Kind = SyntaxKind.DocumentationCommentTrivia Then
 
                ' [token] [whitespace] [trivia] case
                If Me.Token1.IsLastTokenOfStatementWithEndOfLine() AndAlso trivia1.Kind = SyntaxKind.None Then
                    Return LineColumnRule.PreserveSpacesOrUseDefaultIndentation(spaces:=1)
                End If
 
                If trivia1.Kind = SyntaxKind.LineContinuationTrivia Then
                    Return LineColumnRule.PreserveSpacesOrUseDefaultIndentation(spaces:=1)
                End If
 
                If Me.FormattingRules.GetAdjustNewLinesOperation(Me.Token1, Me.Token2) IsNot Nothing Then
                    Return LineColumnRule.PreserveLinesWithDefaultIndentation(lines:=0)
                End If
 
                Return LineColumnRule.PreserveLinesWithGivenIndentation(lines:=0)
            End If
 
            ' skipped tokens
            If trivia2.Kind = SyntaxKind.SkippedTokensTrivia Then
                _succeeded = False
            End If
 
            Return LineColumnRule.Preserve
        End Function
 
        Protected Overrides Function ContainsImplicitLineBreak(syntaxTrivia As SyntaxTrivia) As Boolean
            Return False
        End Function
 
        Private Function IsStartOrEndOfFile(trivia1 As SyntaxTrivia, trivia2 As SyntaxTrivia) As Boolean
            Return (Token1.Kind = 0 OrElse Token2.Kind = 0) AndAlso (trivia1.Kind = 0 OrElse trivia2.Kind = 0)
        End Function
 
        Protected Overloads Overrides Function Format(lineColumn As LineColumn,
                                                      trivia As SyntaxTrivia,
                                                      changes As ArrayBuilder(Of SyntaxTrivia),
                                                      cancellationToken As CancellationToken) As LineColumnDelta
            If trivia.HasStructure Then
                Return FormatStructuredTrivia(lineColumn, trivia, changes, cancellationToken)
            End If
 
            If trivia.Kind = SyntaxKind.LineContinuationTrivia Then
                trivia = FormatLineContinuationTrivia(trivia)
            End If
 
            changes.Add(trivia)
            Return GetLineColumnDelta(lineColumn, trivia)
        End Function
 
        Protected Overloads Overrides Function Format(lineColumn As LineColumn,
                                                      trivia As SyntaxTrivia,
                                                      changes As ArrayBuilder(Of TextChange),
                                                      cancellationToken As CancellationToken) As LineColumnDelta
            If trivia.HasStructure Then
                Return FormatStructuredTrivia(lineColumn, trivia, changes, cancellationToken)
            End If
 
            If trivia.Kind = SyntaxKind.LineContinuationTrivia Then
                Dim lineContinuation = FormatLineContinuationTrivia(trivia)
 
                If trivia <> lineContinuation Then
                    changes.Add(New TextChange(trivia.FullSpan, lineContinuation.ToFullString()))
                End If
 
                Return GetLineColumnDelta(lineColumn, lineContinuation)
            End If
 
            Return GetLineColumnDelta(lineColumn, trivia)
        End Function
 
        Private Function FormatLineContinuationTrivia(trivia As SyntaxTrivia) As SyntaxTrivia
            If trivia.ToFullString() <> _lineContinuationTrivia.ToFullString() Then
                Return _lineContinuationTrivia
            End If
 
            Return trivia
        End Function
 
        Private Function FormatStructuredTrivia(lineColumn As LineColumn,
                                                trivia As SyntaxTrivia,
                                                changes As ArrayBuilder(Of SyntaxTrivia),
                                                cancellationToken As CancellationToken) As LineColumnDelta
            If trivia.Kind = SyntaxKind.SkippedTokensTrivia Then
                ' don't touch anything if it contains skipped tokens
                _succeeded = False
 
                changes.Add(trivia)
                Return GetLineColumnDelta(lineColumn, trivia)
            End If
 
            ' TODO : make document comment to be formatted by structured trivia formatter as well.
            If trivia.Kind <> SyntaxKind.DocumentationCommentTrivia Then
                Dim result = VisualBasicStructuredTriviaFormatEngine.FormatTrivia(trivia, Me.InitialLineColumn.Column, Me.Options, Me.FormattingRules, cancellationToken)
                Dim formattedTrivia = SyntaxFactory.Trivia(DirectCast(result.GetFormattedRoot(cancellationToken), StructuredTriviaSyntax))
 
                changes.Add(formattedTrivia)
                Return GetLineColumnDelta(lineColumn, formattedTrivia)
            End If
 
            Dim docComment = FormatDocumentComment(lineColumn, trivia)
            changes.Add(docComment)
 
            Return GetLineColumnDelta(lineColumn, docComment)
        End Function
 
        Private Function FormatStructuredTrivia(lineColumn As LineColumn,
                                                trivia As SyntaxTrivia,
                                                changes As ArrayBuilder(Of TextChange),
                                                cancellationToken As CancellationToken) As LineColumnDelta
            If trivia.Kind = SyntaxKind.SkippedTokensTrivia Then
                ' don't touch anything if it contains skipped tokens
                _succeeded = False
                Return GetLineColumnDelta(lineColumn, trivia)
            End If
 
            ' TODO : make document comment to be formatted by structured trivia formatter as well.
            If trivia.Kind <> SyntaxKind.DocumentationCommentTrivia Then
                Dim result = VisualBasicStructuredTriviaFormatEngine.FormatTrivia(
                    trivia, Me.InitialLineColumn.Column, Me.Options, Me.FormattingRules, cancellationToken)
 
                If result.GetTextChanges(cancellationToken).Count = 0 Then
                    Return GetLineColumnDelta(lineColumn, trivia)
                End If
 
                changes.AddRange(result.GetTextChanges(cancellationToken))
 
                Dim formattedTrivia = SyntaxFactory.Trivia(DirectCast(result.GetFormattedRoot(cancellationToken), StructuredTriviaSyntax))
                Return GetLineColumnDelta(lineColumn, formattedTrivia)
            End If
 
            Dim docComment = FormatDocumentComment(lineColumn, trivia)
            If docComment <> trivia Then
                changes.Add(New TextChange(trivia.FullSpan, docComment.ToFullString()))
            End If
 
            Return GetLineColumnDelta(lineColumn, docComment)
        End Function
 
        Private Function FormatDocumentComment(lineColumn As LineColumn, trivia As SyntaxTrivia) As SyntaxTrivia
 
            Dim indentation = Me.Context.GetBaseIndentation(trivia.SpanStart)
 
            Dim text = trivia.ToFullString()
 
            ' When the doc comment is parsed from source, even if it is only one
            ' line long, the end-of-line will get included into the trivia text.
            ' If the doc comment was parsed from a text fragment, there may not be
            ' an end-of-line at all. We need to trim the end before we check the
            ' number of line breaks in the text.
#If NET Then
            Dim textWithoutFinalNewLine = text.TrimEnd()
#Else
            Dim textWithoutFinalNewLine = text.TrimEnd(Nothing)
#End If
            If Not textWithoutFinalNewLine.ContainsLineBreak() Then
                Return trivia
            End If
 
            Dim singlelineDocComments = text.ReindentStartOfXmlDocumentationComment(
                forceIndentation:=True,
                indentation:=indentation,
                indentationDelta:=0,
                useTab:=Options.UseTabs,
                tabSize:=Options.TabSize,
                newLine:=Options.NewLine)
 
            If text = singlelineDocComments Then
                Return trivia
            End If
 
            Dim singlelineDocCommentTrivia = SyntaxFactory.ParseLeadingTrivia(singlelineDocComments)
            Contract.ThrowIfFalse(singlelineDocCommentTrivia.Count = 1)
 
            Return singlelineDocCommentTrivia.ElementAt(0)
        End Function
 
        Protected Overrides Function LineContinuationFollowedByWhitespaceComment(trivia As SyntaxTrivia, nextTrivia As SyntaxTrivia) As Boolean
            Return trivia.Kind = SyntaxKind.LineContinuationTrivia AndAlso nextTrivia.Kind = SyntaxKind.CommentTrivia
        End Function
 
        Protected Overrides Function IsVisualBasicComment(trivia As SyntaxTrivia) As Boolean
            Return trivia.Kind = SyntaxKind.CommentTrivia
        End Function
    End Class
End Namespace