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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.Diagnostics.CodeAnalysis;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.Host;
using Microsoft.CodeAnalysis.LanguageService;
using Microsoft.CodeAnalysis.Shared.Collections;
using Microsoft.CodeAnalysis.Shared.Extensions;
using Microsoft.CodeAnalysis.Shared.Utilities;
using Roslyn.Utilities;
namespace Microsoft.CodeAnalysis.QuickInfo
{
internal abstract partial class CommonSemanticQuickInfoProvider : CommonQuickInfoProvider
{
protected override async Task<QuickInfoItem?> BuildQuickInfoAsync(
QuickInfoContext context, SyntaxToken token)
{
var (tokenInformation, supportedPlatforms) = await ComputeQuickInfoDataAsync(context, token).ConfigureAwait(false);
if (tokenInformation.Symbols.IsDefaultOrEmpty)
return null;
var cancellationToken = context.CancellationToken;
var semanticModel = await context.Document.GetRequiredSemanticModelAsync(cancellationToken).ConfigureAwait(false);
var services = context.Document.Project.Solution.Services;
return await CreateContentAsync(
services, semanticModel, token, tokenInformation, supportedPlatforms, context.Options, cancellationToken).ConfigureAwait(false);
}
protected override async Task<QuickInfoItem?> BuildQuickInfoAsync(
CommonQuickInfoContext context, SyntaxToken token)
{
var tokenInformation = BindToken(context.Services, context.SemanticModel, token, context.CancellationToken);
if (tokenInformation.Symbols.IsDefaultOrEmpty)
return null;
return await CreateContentAsync(
context.Services, context.SemanticModel, token, tokenInformation, supportedPlatforms: null, context.Options, context.CancellationToken).ConfigureAwait(false);
}
private async Task<(TokenInformation tokenInformation, SupportedPlatformData? supportedPlatforms)> ComputeQuickInfoDataAsync(
QuickInfoContext context,
SyntaxToken token)
{
var cancellationToken = context.CancellationToken;
var document = context.Document;
var linkedDocumentIds = document.GetLinkedDocumentIds();
if (linkedDocumentIds.Any())
return await ComputeFromLinkedDocumentsAsync(context, token, linkedDocumentIds).ConfigureAwait(false);
var semanticModel = await document.GetRequiredSemanticModelAsync(cancellationToken).ConfigureAwait(false);
var services = document.Project.Solution.Services;
var tokenInformation = BindToken(services, semanticModel, token, cancellationToken);
return (tokenInformation, supportedPlatforms: null);
}
private async Task<(TokenInformation, SupportedPlatformData supportedPlatforms)> ComputeFromLinkedDocumentsAsync(
QuickInfoContext context,
SyntaxToken token,
ImmutableArray<DocumentId> linkedDocumentIds)
{
// Linked files/shared projects: imagine the following when GOO is false
// #if GOO
// int x = 3;
// #endif
// var y = x$$;
//
// 'x' will bind as an error type, so we'll show incorrect information.
// Instead, we need to find the head in which we get the best binding,
// which in this case is the one with no errors.
var cancellationToken = context.CancellationToken;
var document = context.Document;
var solution = document.Project.Solution;
var services = solution.Services;
var semanticModel = await document.GetRequiredSemanticModelAsync(cancellationToken).ConfigureAwait(false);
var mainTokenInformation = BindToken(services, semanticModel, token, cancellationToken);
var candidateProjects = new List<ProjectId> { document.Project.Id };
var invalidProjects = new List<ProjectId>();
var candidateResults = new List<(DocumentId docId, TokenInformation tokenInformation)>
{
(document.Id, mainTokenInformation)
};
foreach (var linkedDocumentId in linkedDocumentIds)
{
var linkedDocument = solution.GetRequiredDocument(linkedDocumentId);
var linkedModel = await linkedDocument.GetRequiredSemanticModelAsync(cancellationToken).ConfigureAwait(false);
var linkedToken = FindTokenInLinkedDocument(token, linkedModel, cancellationToken);
if (linkedToken != default)
{
// Not in an inactive region, so this file is a candidate.
candidateProjects.Add(linkedDocumentId.ProjectId);
var linkedSymbols = BindToken(services, linkedModel, linkedToken, cancellationToken);
candidateResults.Add((linkedDocumentId, linkedSymbols));
}
}
// Take the first result with no errors.
// If every file binds with errors, take the first candidate, which is from the current file.
var bestBinding = candidateResults.FirstOrNull(c => HasNoErrors(c.tokenInformation.Symbols))
?? candidateResults.First();
if (bestBinding.tokenInformation.Symbols.IsDefaultOrEmpty)
return default;
// We calculate the set of supported projects
candidateResults.Remove(bestBinding);
foreach (var (docId, tokenInformation) in candidateResults)
{
// Does the candidate have anything remotely equivalent?
if (!tokenInformation.Symbols.Intersect(bestBinding.tokenInformation.Symbols, LinkedFilesSymbolEquivalenceComparer.Instance).Any())
invalidProjects.Add(docId.ProjectId);
}
var supportedPlatforms = new SupportedPlatformData(solution, invalidProjects, candidateProjects);
return (bestBinding.tokenInformation, supportedPlatforms);
}
private static bool HasNoErrors(ImmutableArray<ISymbol> symbols)
=> symbols.Length > 0
&& !ErrorVisitor.ContainsError(symbols.FirstOrDefault());
private static SyntaxToken FindTokenInLinkedDocument(
SyntaxToken token,
SemanticModel linkedModel,
CancellationToken cancellationToken)
{
var root = linkedModel.SyntaxTree.GetRoot(cancellationToken);
if (root == null)
return default;
// Don't search trivia because we want to ignore inactive regions
var linkedToken = root.FindToken(token.SpanStart);
// The new and old tokens should have the same span?
return token.Span == linkedToken.Span ? linkedToken : default;
}
protected static Task<QuickInfoItem> CreateContentAsync(
SolutionServices services,
SemanticModel semanticModel,
SyntaxToken token,
TokenInformation tokenInformation,
SupportedPlatformData? supportedPlatforms,
SymbolDescriptionOptions options,
CancellationToken cancellationToken)
{
var syntaxFactsService = services.GetRequiredLanguageService<ISyntaxFactsService>(semanticModel.Language);
var symbols = tokenInformation.Symbols;
// if generating quick info for an attribute, prefer bind to the class instead of the constructor
if (syntaxFactsService.IsAttributeName(token.Parent!))
{
symbols = symbols.OrderBy((s1, s2) =>
s1.Kind == s2.Kind ? 0 :
s1.Kind == SymbolKind.NamedType ? -1 :
s2.Kind == SymbolKind.NamedType ? 1 : 0).ToImmutableArray();
}
return QuickInfoUtilities.CreateQuickInfoItemAsync(
services, semanticModel, token.Span, symbols, supportedPlatforms,
tokenInformation.ShowAwaitReturn, tokenInformation.NullableFlowState, options, cancellationToken);
}
protected abstract bool GetBindableNodeForTokenIndicatingLambda(SyntaxToken token, [NotNullWhen(returnValue: true)] out SyntaxNode? found);
protected abstract bool GetBindableNodeForTokenIndicatingPossibleIndexerAccess(SyntaxToken token, [NotNullWhen(returnValue: true)] out SyntaxNode? found);
protected abstract bool GetBindableNodeForTokenIndicatingMemberAccess(SyntaxToken token, out SyntaxToken found);
protected virtual NullableFlowState GetNullabilityAnalysis(SemanticModel semanticModel, ISymbol symbol, SyntaxNode node, CancellationToken cancellationToken) => NullableFlowState.None;
private TokenInformation BindToken(
SolutionServices services, SemanticModel semanticModel, SyntaxToken token, CancellationToken cancellationToken)
{
var languageServices = services.GetLanguageServices(semanticModel.Language);
var syntaxFacts = languageServices.GetRequiredService<ISyntaxFactsService>();
var enclosingType = semanticModel.GetEnclosingNamedType(token.SpanStart, cancellationToken);
var symbols = GetSymbolsFromToken(token, services, semanticModel, cancellationToken);
var bindableParent = syntaxFacts.TryGetBindableParent(token);
var overloads = bindableParent != null
? semanticModel.GetMemberGroup(bindableParent, cancellationToken)
: ImmutableArray<ISymbol>.Empty;
symbols = symbols.Where(IsOk)
.Where(s => IsAccessible(s, enclosingType))
.Concat(overloads)
.Distinct(SymbolEquivalenceComparer.Instance)
.ToImmutableArray();
if (symbols.Any())
{
var firstSymbol = symbols.First();
var isAwait = syntaxFacts.IsAwaitKeyword(token);
var nullableFlowState = NullableFlowState.None;
if (bindableParent != null)
{
nullableFlowState = GetNullabilityAnalysis(semanticModel, firstSymbol, bindableParent, cancellationToken);
}
return new TokenInformation(symbols, isAwait, nullableFlowState);
}
// Couldn't bind the token to specific symbols. If it's an operator, see if we can at
// least bind it to a type.
if (syntaxFacts.IsOperator(token))
{
var typeInfo = semanticModel.GetTypeInfo(token.Parent!, cancellationToken);
if (IsOk(typeInfo.Type))
{
return new TokenInformation(ImmutableArray.Create<ISymbol>(typeInfo.Type));
}
}
return new TokenInformation(ImmutableArray<ISymbol>.Empty);
}
private ImmutableArray<ISymbol> GetSymbolsFromToken(SyntaxToken token, SolutionServices services, SemanticModel semanticModel, CancellationToken cancellationToken)
{
if (GetBindableNodeForTokenIndicatingLambda(token, out var lambdaSyntax))
{
var symbol = semanticModel.GetSymbolInfo(lambdaSyntax, cancellationToken).Symbol;
return symbol != null ? ImmutableArray.Create(symbol) : ImmutableArray<ISymbol>.Empty;
}
if (GetBindableNodeForTokenIndicatingPossibleIndexerAccess(token, out var elementAccessExpression))
{
var symbol = semanticModel.GetSymbolInfo(elementAccessExpression, cancellationToken).Symbol;
if (symbol?.IsIndexer() == true)
{
return ImmutableArray.Create(symbol);
}
}
if (GetBindableNodeForTokenIndicatingMemberAccess(token, out var accessedMember))
{
// If the cursor is on the dot in an invocation `x.M()`, then we'll consider the cursor was placed on `M`
token = accessedMember;
}
return semanticModel.GetSemanticInfo(token, services, cancellationToken)
.GetSymbols(includeType: true);
}
private static bool IsOk([NotNullWhen(returnValue: true)] ISymbol? symbol)
{
if (symbol == null)
return false;
if (symbol.IsErrorType())
return false;
if (symbol is ITypeParameterSymbol { TypeParameterKind: TypeParameterKind.Cref })
return false;
return true;
}
private static bool IsAccessible(ISymbol symbol, INamedTypeSymbol? within)
=> within == null
|| symbol.IsAccessibleWithin(within);
}
}
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