protected async Task <List <TextChange> > AdjustIndentationAsync(FormattingContext context, CancellationToken cancellationToken, Range?range = null)
{
// In this method, the goal is to make final adjustments to the indentation of each line.
// We will take into account the following,
// 1. The indentation due to nested C# structures
// 2. The indentation due to Razor and HTML constructs
var text = context.SourceText;
range ??= TextSpan.FromBounds(0, text.Length).AsRange(text);
// To help with figuring out the correct indentation, first we will need the indentation
// that the C# formatter wants to apply in the following locations,
// 1. The start and end of each of our source mappings
// 2. The start of every line that starts in C# context
// Due to perf concerns, we only want to invoke the real C# formatter once.
// So, let's collect all the significant locations that we want to obtain the CSharpDesiredIndentations for.
var significantLocations = new HashSet <int>();
// First, collect all the locations at the beginning and end of each source mapping.
var sourceMappingMap = new Dictionary <int, int>();
foreach (var mapping in context.CodeDocument.GetCSharpDocument().SourceMappings)
{
var mappingSpan = new TextSpan(mapping.OriginalSpan.AbsoluteIndex, mapping.OriginalSpan.Length);
if (!ShouldFormat(context, mappingSpan, allowImplicitStatements: true))
{
// We don't care about this range as this can potentially lead to incorrect scopes.
continue;
}
var originalStartLocation = mapping.OriginalSpan.AbsoluteIndex;
var projectedStartLocation = mapping.GeneratedSpan.AbsoluteIndex;
sourceMappingMap[originalStartLocation] = projectedStartLocation;
significantLocations.Add(projectedStartLocation);
var originalEndLocation = mapping.OriginalSpan.AbsoluteIndex + mapping.OriginalSpan.Length + 1;
var projectedEndLocation = mapping.GeneratedSpan.AbsoluteIndex + mapping.GeneratedSpan.Length + 1;
sourceMappingMap[originalEndLocation] = projectedEndLocation;
significantLocations.Add(projectedEndLocation);
}
// Next, collect all the line starts that start in C# context
var indentations = context.GetIndentations();
var lineStartMap = new Dictionary <int, int>();
for (var i = range.Start.Line; i <= range.End.Line; i++)
{
if (indentations[i].EmptyOrWhitespaceLine)
{
// We should remove whitespace on empty lines.
continue;
}
var line = context.SourceText.Lines[i];
var lineStart = line.GetFirstNonWhitespacePosition() ?? line.Start;
var lineStartSpan = new TextSpan(lineStart, 0);
if (!ShouldFormat(context, lineStartSpan, allowImplicitStatements: true))
{
// We don't care about this range as this can potentially lead to incorrect scopes.
continue;
}
if (DocumentMappingService.TryMapToProjectedDocumentPosition(context.CodeDocument, lineStart, out _, out var projectedLineStart))
{
lineStartMap[lineStart] = projectedLineStart;
significantLocations.Add(projectedLineStart);
}
}
// Now, invoke the C# formatter to obtain the CSharpDesiredIndentation for all significant locations.
var significantLocationIndentation = await CSharpFormatter.GetCSharpIndentationAsync(context, significantLocations, cancellationToken);
// Build source mapping indentation scopes.
var sourceMappingIndentations = new SortedDictionary <int, int>();
foreach (var originalLocation in sourceMappingMap.Keys)
{
var significantLocation = sourceMappingMap[originalLocation];
if (!significantLocationIndentation.TryGetValue(significantLocation, out var indentation))
{
// C# formatter didn't return an indentation for this. Skip.
continue;
}
sourceMappingIndentations[originalLocation] = indentation;
}
var sourceMappingIndentationScopes = sourceMappingIndentations.Keys.ToArray();
// Build lineStart indentation map.
var lineStartIndentations = new Dictionary <int, int>();
foreach (var originalLocation in lineStartMap.Keys)
{
var significantLocation = lineStartMap[originalLocation];
if (!significantLocationIndentation.TryGetValue(significantLocation, out var indentation))
{
// C# formatter didn't return an indentation for this. Skip.
continue;
}
lineStartIndentations[originalLocation] = indentation;
}
// Now, let's combine the C# desired indentation with the Razor and HTML indentation for each line.
var newIndentations = new Dictionary <int, int>();
for (var i = range.Start.Line; i <= range.End.Line; i++)
{
if (indentations[i].EmptyOrWhitespaceLine)
{
// We should remove whitespace on empty lines.
newIndentations[i] = 0;
continue;
}
var minCSharpIndentation = context.GetIndentationOffsetForLevel(indentations[i].MinCSharpIndentLevel);
var line = context.SourceText.Lines[i];
var lineStart = line.GetFirstNonWhitespacePosition() ?? line.Start;
var lineStartSpan = new TextSpan(lineStart, 0);
if (!ShouldFormat(context, lineStartSpan, allowImplicitStatements: true))
{
// We don't care about this line as it lies in an area we don't want to format.
continue;
}
if (!lineStartIndentations.TryGetValue(lineStart, out var csharpDesiredIndentation))
{
// Couldn't remap. This is probably a non-C# location.
// Use SourceMapping indentations to locate the C# scope of this line.
// E.g,
//
// @if (true) {
// <div>
// |</div>
// }
//
// We can't find a direct mapping at |, but we can infer its base indentation from the
// indentation of the latest source mapping prior to this line.
// We use binary search to find that spot.
var index = Array.BinarySearch(sourceMappingIndentationScopes, lineStart);
if (index < 0)
{
// Couldn't find the exact value. Find the index of the element to the left of the searched value.
index = (~index) - 1;
}
if (index < 0)
{
// If we _still_ couldn't find the right indentation, then it probably means that the text is
// before the first source mapping location, so we can just place it in the minimum spot (realistically
// at index 0 in the razor file, but we use minCSharpIndentation because we're adjusting based on the
// generated file here)
csharpDesiredIndentation = minCSharpIndentation;
}
else
{
// index will now be set to the same value as the end of the closest source mapping.
var absoluteIndex = sourceMappingIndentationScopes[index];
csharpDesiredIndentation = sourceMappingIndentations[absoluteIndex];
// This means we didn't find an exact match and so we used the indentation of the end of a previous mapping.
// So let's use the MinCSharpIndentation of that same location if possible.
if (context.TryGetFormattingSpan(absoluteIndex, out var span))
{
minCSharpIndentation = context.GetIndentationOffsetForLevel(span.MinCSharpIndentLevel);
}
}
}
// Now let's use that information to figure out the effective C# indentation.
// This should be based on context.
// For instance, lines inside @code/@functions block should be reduced one level
// and lines inside @{} should be reduced by two levels.
if (csharpDesiredIndentation < minCSharpIndentation)
{
// CSharp formatter doesn't want to indent this. Let's not touch it.
continue;
}
var effectiveCSharpDesiredIndentation = csharpDesiredIndentation - minCSharpIndentation;
var razorDesiredIndentation = context.GetIndentationOffsetForLevel(indentations[i].IndentationLevel);
if (indentations[i].StartsInHtmlContext)
{
// This is a non-C# line.
if (context.IsFormatOnType)
{
// HTML formatter doesn't run in the case of format on type.
// Let's stick with our syntax understanding of HTML to figure out the desired indentation.
}
else
{
// Given that the HTML formatter ran before this, we can assume
// HTML is already correctly formatted. So we can use the existing indentation as is.
// We need to make sure to use the indentation size, as this will get passed to
// GetIndentationString eventually.
razorDesiredIndentation = indentations[i].ExistingIndentationSize;
}
}
var effectiveDesiredIndentation = razorDesiredIndentation + effectiveCSharpDesiredIndentation;
// This will now contain the indentation we ultimately want to apply to this line.
newIndentations[i] = effectiveDesiredIndentation;
}
// Now that we have collected all the indentations for each line, let's convert them to text edits.
var changes = new List <TextChange>();
foreach (var item in newIndentations)
{
var line = item.Key;
var indentation = item.Value;
Debug.Assert(indentation >= 0, "Negative indentation. This is unexpected.");
var existingIndentationLength = indentations[line].ExistingIndentation;
var spanToReplace = new TextSpan(context.SourceText.Lines[line].Start, existingIndentationLength);
var effectiveDesiredIndentation = context.GetIndentationString(indentation);
changes.Add(new TextChange(spanToReplace, effectiveDesiredIndentation));
}
return(changes);
}
protected bool ShouldFormat(FormattingContext context, Position position, bool allowImplicitStatements)
{
// We should be called with start positions of various C# SourceMappings.
if (position.Character == 0)
{
// The mapping starts at 0. It can't be anything special but pure C#. Let's format it.
return(true);
}
var sourceText = context.SourceText;
var absoluteIndex = sourceText.Lines[(int)position.Line].Start + (int)position.Character;
if (IsImplicitStatementStart() && !allowImplicitStatements)
{
return(false);
}
var syntaxTree = context.CodeDocument.GetSyntaxTree();
var change = new SourceChange(absoluteIndex, 0, string.Empty);
var owner = syntaxTree.Root.LocateOwner(change);
if (owner == null)
{
// Can't determine owner of this position. Optimistically allow formatting.
return(true);
}
if (IsInHtmlTag() ||
IsInSingleLineDirective() ||
IsImplicitOrExplicitExpression())
{
return(false);
}
return(true);
bool IsImplicitStatementStart()
{
// We will return true if the position points to the start of the C# portion of an implicit statement.
// `@|for(...)` - true
// `@|if(...)` - true
// `@{|...` - false
// `@code {|...` - false
//
var previousCharIndex = absoluteIndex - 1;
var previousChar = sourceText[previousCharIndex];
if (previousChar != '@')
{
// Not an implicit statement.
return(false);
}
// This is an implicit statement if the previous '@' is not C# (meaning it shouldn't have a projected mapping).
return(!DocumentMappingService.TryMapToProjectedDocumentPosition(context.CodeDocument, previousCharIndex, out _, out _));
}
bool IsInHtmlTag()
{
// E.g, (| is position)
//
// `<p csharpattr="|Variable">` - true
//
return(owner.AncestorsAndSelf().Any(
n => n is MarkupStartTagSyntax || n is MarkupTagHelperStartTagSyntax || n is MarkupEndTagSyntax || n is MarkupTagHelperEndTagSyntax));
}
bool IsInSingleLineDirective()
{
// E.g, (| is position)
//
// `@inject |SomeType SomeName` - true
//
// Note: @using directives don't have a descriptor associated with them, hence the extra null check.
//
return(owner.AncestorsAndSelf().Any(
n => n is RazorDirectiveSyntax directive && (directive.DirectiveDescriptor == null || directive.DirectiveDescriptor.Kind == DirectiveKind.SingleLine)));
}
bool IsImplicitOrExplicitExpression()
{
// E.g, (| is position)
//
// `@|foo` - true
// `@(|foo)` - true
//
return(owner.AncestorsAndSelf().Any(n => n is CSharpImplicitExpressionSyntax || n is CSharpExplicitExpressionSyntax));
}
}
private List <TextChange> AdjustIndentation(FormattingContext context, CancellationToken cancellationToken, Range range = null)
{
// In this method, the goal is to make final adjustments to the indentation of each line.
// We will take into account the following,
// 1. The indentation due to nested C# structures
// 2. The indentation due to Razor and HTML constructs
var text = context.SourceText;
range ??= TextSpan.FromBounds(0, text.Length).AsRange(text);
// First, let's build an understanding of the desired C# indentation at the beginning and end of each source mapping.
var sourceMappingIndentations = new SortedDictionary <int, int>();
foreach (var mapping in context.CodeDocument.GetCSharpDocument().SourceMappings)
{
var mappingSpan = new TextSpan(mapping.OriginalSpan.AbsoluteIndex, mapping.OriginalSpan.Length);
var mappingRange = mappingSpan.AsRange(context.SourceText);
if (!ShouldFormat(context, mappingRange.Start))
{
// We don't care about this range as this can potentially lead to incorrect scopes.
continue;
}
var startIndentation = CSharpFormatter.GetCSharpIndentation(context, mapping.GeneratedSpan.AbsoluteIndex, cancellationToken);
sourceMappingIndentations[mapping.OriginalSpan.AbsoluteIndex] = startIndentation;
var endIndentation = CSharpFormatter.GetCSharpIndentation(context, mapping.GeneratedSpan.AbsoluteIndex + mapping.GeneratedSpan.Length + 1, cancellationToken);
sourceMappingIndentations[mapping.OriginalSpan.AbsoluteIndex + mapping.OriginalSpan.Length + 1] = endIndentation;
}
var sourceMappingIndentationScopes = sourceMappingIndentations.Keys.ToArray();
// Now, let's combine the C# desired indentation with the Razor and HTML indentation for each line.
var newIndentations = new Dictionary <int, int>();
for (var i = range.Start.Line; i <= range.End.Line; i++)
{
var line = context.SourceText.Lines[i];
if (line.Span.Length == 0)
{
// We don't want to indent empty lines.
continue;
}
var lineStart = line.Start;
int csharpDesiredIndentation;
if (DocumentMappingService.TryMapToProjectedDocumentPosition(context.CodeDocument, lineStart, out _, out var projectedLineStart))
{
// We were able to map this line to C# directly.
csharpDesiredIndentation = CSharpFormatter.GetCSharpIndentation(context, projectedLineStart, cancellationToken);
}
else
{
// Couldn't remap. This is probably a non-C# location.
// Use SourceMapping indentations to locate the C# scope of this line.
// E.g,
//
// @if (true) {
// <div>
// |</div>
// }
//
// We can't find a direct mapping at |, but we can infer its base indentation from the
// indentation of the latest source mapping prior to this line.
// We use binary search to find that spot.
var index = Array.BinarySearch(sourceMappingIndentationScopes, lineStart);
if (index < 0)
{
// Couldn't find the exact value. Find the index of the element to the left of the searched value.
index = (~index) - 1;
}
// This will now be set to the same value as the end of the closest source mapping.
csharpDesiredIndentation = index < 0 ? 0 : sourceMappingIndentations[sourceMappingIndentationScopes[index]];
}
// Now let's use that information to figure out the effective C# indentation.
// This should be based on context.
// For instance, lines inside @code/@functions block should be reduced one level
// and lines inside @{} should be reduced by two levels.
var csharpDesiredIndentLevel = context.GetIndentationLevelForOffset(csharpDesiredIndentation);
var minCSharpIndentLevel = context.Indentations[i].MinCSharpIndentLevel;
if (csharpDesiredIndentLevel < minCSharpIndentLevel)
{
// CSharp formatter doesn't want to indent this. Let's not touch it.
continue;
}
var effectiveCSharpDesiredIndentationLevel = csharpDesiredIndentLevel - minCSharpIndentLevel;
var razorDesiredIndentationLevel = context.Indentations[i].IndentationLevel;
if (!context.Indentations[i].StartsInCSharpContext)
{
// This is a non-C# line. Given that the HTML formatter ran before this, we can assume
// HTML is already correctly formatted. So we can use the existing indentation as is.
razorDesiredIndentationLevel = context.GetIndentationLevelForOffset(context.Indentations[i].ExistingIndentation);
}
var effectiveDesiredIndentationLevel = razorDesiredIndentationLevel + effectiveCSharpDesiredIndentationLevel;
// This will now contain the indentation we ultimately want to apply to this line.
newIndentations[i] = effectiveDesiredIndentationLevel;
}
// Now that we have collected all the indentations for each line, let's convert them to text edits.
var changes = new List <TextChange>();
foreach (var item in newIndentations)
{
var line = item.Key;
var indentationLevel = item.Value;
Debug.Assert(indentationLevel >= 0, "Negative indent level. This is unexpected.");
var existingIndentationLength = context.Indentations[line].ExistingIndentation;
var spanToReplace = new TextSpan(context.SourceText.Lines[line].Start, existingIndentationLength);
var effectiveDesiredIndentation = context.GetIndentationLevelString(indentationLevel);
changes.Add(new TextChange(spanToReplace, effectiveDesiredIndentation));
}
return(changes);
}
public async override Task <FormattingResult> ExecuteAsync(FormattingContext context, FormattingResult result, CancellationToken cancellationToken)
{
if (!context.IsFormatOnType || result.Kind != RazorLanguageKind.CSharp)
{
// We don't want to handle regular formatting or non-C# on type formatting here.
return(result);
}
// Normalize and re-map the C# edits.
var codeDocument = context.CodeDocument;
var csharpText = codeDocument.GetCSharpSourceText();
var textEdits = result.Edits;
if (textEdits.Length == 0)
{
if (!DocumentMappingService.TryMapToProjectedDocumentPosition(codeDocument, context.HostDocumentIndex, out _, out var projectedIndex))
{
_logger.LogWarning($"Failed to map to projected position for document {context.Uri}.");
return(result);
}
// Ask C# for formatting changes.
var indentationOptions = new RazorIndentationOptions(
UseTabs: !context.Options.InsertSpaces,
TabSize: context.Options.TabSize,
IndentationSize: context.Options.TabSize);
var autoFormattingOptions = new RazorAutoFormattingOptions(
formatOnReturn: true, formatOnTyping: true, formatOnSemicolon: true, formatOnCloseBrace: true);
var formattingChanges = await RazorCSharpFormattingInteractionService.GetFormattingChangesAsync(
context.CSharpWorkspaceDocument,
typedChar : context.TriggerCharacter,
projectedIndex,
indentationOptions,
autoFormattingOptions,
indentStyle : CodeAnalysis.Formatting.FormattingOptions.IndentStyle.Smart,
cancellationToken).ConfigureAwait(false);
if (formattingChanges.IsEmpty)
{
_logger.LogInformation("Received no results.");
return(result);
}
textEdits = formattingChanges.Select(change => change.AsTextEdit(csharpText)).ToArray();
_logger.LogInformation($"Received {textEdits.Length} results from C#.");
}
var normalizedEdits = NormalizeTextEdits(csharpText, textEdits, out var originalTextWithChanges);
var mappedEdits = RemapTextEdits(codeDocument, normalizedEdits, result.Kind);
var filteredEdits = FilterCSharpTextEdits(context, mappedEdits);
if (filteredEdits.Length == 0)
{
// There are no CSharp edits for us to apply. No op.
return(new FormattingResult(filteredEdits));
}
// Find the lines that were affected by these edits.
var originalText = codeDocument.GetSourceText();
var changes = filteredEdits.Select(e => e.AsTextChange(originalText));
// Apply the format on type edits sent over by the client.
var formattedText = ApplyChangesAndTrackChange(originalText, changes, out _, out var spanAfterFormatting);
var changedContext = await context.WithTextAsync(formattedText);
var rangeAfterFormatting = spanAfterFormatting.AsRange(formattedText);
cancellationToken.ThrowIfCancellationRequested();
// We make an optimistic attempt at fixing corner cases.
var cleanupChanges = CleanupDocument(changedContext, rangeAfterFormatting);
var cleanedText = formattedText.WithChanges(cleanupChanges);
changedContext = await changedContext.WithTextAsync(cleanedText);
cancellationToken.ThrowIfCancellationRequested();
// At this point we should have applied all edits that adds/removes newlines.
// Let's now ensure the indentation of each of those lines is correct.
// We only want to adjust the range that was affected.
// We need to take into account the lines affected by formatting as well as cleanup.
var lineDelta = LineDelta(formattedText, cleanupChanges, out var firstPosition, out var lastPosition);
// Okay hear me out, I know this looks lazy, but it totally makes sense.
// This method is called with edits that the C# formatter wants to make, and from those edits we work out which
// other edits to apply etc. Fine, all good so far. BUT its totally possible that the user typed a closing brace
// in the same position as the C# formatter thought it should be, on the line _after_ the code that the C# formatter
// reformatted.
//
// For example, given:
// if (true){
// }
//
// If the C# formatter is happy with the placement of that close brace then this method will get two edits:
// * On line 1 to indent the if by 4 spaces
// * On line 1 to add a newline and 4 spaces in front of the opening brace
//
// We'll happy format lines 1 and 2, and ignore the closing brace altogether. So, by looking one line further
// we won't have that problem.
if (rangeAfterFormatting.End.Line + lineDelta < cleanedText.Lines.Count)
{
lineDelta++;
}
// Now we know how many lines were affected by the cleanup and formatting, but we don't know where those lines are. For example, given:
//
// @if (true)
// {
// }
// else
// {
// $$}
//
// When typing that close brace, the changes would fix the previous close brace, but the line delta would be 0, so
// we'd format line 6 and call it a day, even though the formatter made an edit on line 3. To fix this we use the
// first and last position of edits made above, and make sure our range encompasses them as well. For convenience
// we calculate these positions in the LineDelta method called above.
// This is essentially: rangeToAdjust = new Range(Math.Min(firstFormattingEdit, userEdit), Math.Max(lastFormattingEdit, userEdit))
var start = rangeAfterFormatting.Start;
if (firstPosition is not null && firstPosition < start)
{
start = firstPosition;
}
var end = new Position(rangeAfterFormatting.End.Line + lineDelta, 0);
if (lastPosition is not null && lastPosition < start)
{
end = lastPosition;
}
var rangeToAdjust = new Range(start, end);
Debug.Assert(rangeToAdjust.End.IsValid(cleanedText), "Invalid range. This is unexpected.");
var indentationChanges = await AdjustIndentationAsync(changedContext, cancellationToken, rangeToAdjust);
if (indentationChanges.Count > 0)
{
// Apply the edits that modify indentation.
cleanedText = cleanedText.WithChanges(indentationChanges);
}
// Now that we have made all the necessary changes to the document. Let's diff the original vs final version and return the diff.
var finalChanges = cleanedText.GetTextChanges(originalText);
var finalEdits = finalChanges.Select(f => f.AsTextEdit(originalText)).ToArray();
if (context.AutomaticallyAddUsings)
{
// Because we need to parse the C# code twice for this operation, lets do a quick check to see if its even necessary
if (textEdits.Any(e => e.NewText.IndexOf("using") != -1))
{
finalEdits = await AddUsingStatementEditsAsync(codeDocument, finalEdits, csharpText, originalTextWithChanges, cancellationToken);
}
}
return(new FormattingResult(finalEdits));
}