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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.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.Editing;
using Microsoft.CodeAnalysis.FindSymbols;
using Microsoft.CodeAnalysis.LanguageService;
using Microsoft.CodeAnalysis.Operations;
using Microsoft.CodeAnalysis.Shared.Extensions;
using Roslyn.Utilities;
namespace Microsoft.CodeAnalysis.InlineMethod;
internal abstract partial class AbstractInlineMethodRefactoringProvider<TMethodDeclarationSyntax, TStatementSyntax, TExpressionSyntax, TInvocationSyntax>
{
private readonly struct InlineMethodContext(
ImmutableArray<TStatementSyntax> statementsToInsertBeforeInvocationOfCallee,
TExpressionSyntax inlineExpression,
bool containsAwaitExpression)
{
/// <summary>
/// Statements that should be inserted to before the invocation location of callee.
/// </summary>
public ImmutableArray<TStatementSyntax> StatementsToInsertBeforeInvocationOfCallee { get; } = statementsToInsertBeforeInvocationOfCallee;
/// <summary>
/// Inline content for the callee method.
/// </summary>
public TExpressionSyntax InlineExpression { get; } = inlineExpression;
/// <summary>
/// Indicate if <see cref="InlineExpression"/> has AwaitExpression in it.
/// </summary>
public bool ContainsAwaitExpression { get; } = containsAwaitExpression;
}
private async Task<InlineMethodContext> GetInlineMethodContextAsync(
Document document,
TMethodDeclarationSyntax calleeMethodNode,
TInvocationSyntax calleeInvocationNode,
IMethodSymbol calleeMethodSymbol,
TExpressionSyntax rawInlineExpression,
MethodParametersInfo methodParametersInfo,
CancellationToken cancellationToken)
{
var inlineExpression = rawInlineExpression;
var syntaxGenerator = SyntaxGenerator.GetGenerator(document);
var callerSemanticModel = await document.GetRequiredSemanticModelAsync(cancellationToken).ConfigureAwait(false);
var calleeDocument = document.Project.Solution.GetRequiredDocument(calleeMethodNode.SyntaxTree);
var calleeSemanticModel = await calleeDocument.GetRequiredSemanticModelAsync(cancellationToken).ConfigureAwait(false);
// Generate a map which the key is the symbol need renaming, value is the new name.
// After inlining, there might be naming conflict because
// case 1: caller's identifier is introduced to callee.
// Example (for identifier):
// Before:
// void Caller()
// {
// int i = 10;
// Callee(i)
// }
// void Callee(int j)
// {
// DoSomething(out var i, j);
// }
// After inline it should be:
// void Caller()
// {
// int i = 10;
// DoSomething(out var i1, i);
// }
// void Callee(int j)
// {
// DoSomething(out var i, j);
// }
// Case 2: callee's parameter is introduced to caller
// Before:
// void Caller()
// {
// int i = 0;
// int j = 1;
// Callee(Foo())
// }
// void Callee(int i)
// {
// Bar(i, out int j);
// }
// After:
// void Caller()
// {
// int i = 10;
// int j = 1;
// int i1 = Foo();
// Bar(i1, out int j2);
// }
// void Callee(int i)
// {
// Bar(i, out int j);
// }
var renameTable = ComputeRenameTable(
_semanticFactsService,
callerSemanticModel,
calleeSemanticModel,
calleeInvocationNode,
rawInlineExpression,
methodParametersInfo.ParametersToGenerateFreshVariablesFor
.SelectAsArray(parameterAndArgument => parameterAndArgument.parameterSymbol), cancellationToken);
// Generate all the statements need to be put in the caller.
// Use the parameter's name to generate declarations in caller might cause conflict in the caller,
// so the rename table is needed to provide with a valid name.
// Example:
// Before:
// void Caller(int i, int j)
// {
// Callee(Foo(), Bar());
// }
// void Callee(int i, int j)
// {
// DoSomething(i, j);
// }
// After:
// void Caller(int i, int j)
// {
// int i1 = Foo();
// int j1 = Bar();
// DoSomething(i1, j1)
// }
// void Callee(int i, int j)
// {
// DoSomething(i, j);
// }
// Here two declaration is generated.
// Another case is
// void Caller()
// {
// Callee(out int i)
// }
// void Callee(out int j)
// {
// DoSomething(out j, out int i);
// }
// After:
// void Caller()
// {
// int i = 10;
// DoSomething(out i, out int i2);
// }
// void Callee(out int j)
// {
// DoSomething(out j, out int i);
// }
var localDeclarationStatementsNeedInsert = GetLocalDeclarationStatementsNeedInsert(
syntaxGenerator,
methodParametersInfo.ParametersToGenerateFreshVariablesFor,
methodParametersInfo.MergeInlineContentAndVariableDeclarationArgument
? ImmutableArray<(IParameterSymbol, string)>.Empty
: methodParametersInfo.ParametersWithVariableDeclarationArgument,
renameTable);
// Get a table which the key is the symbol needs replacement. Value is the replacement syntax node
// Included 3 cases:
// 1. Type arguments (generics)
// Example:
// Before:
// void Caller()
// {
// Callee<int>();
// }
// void Callee<T>() => Print(typeof<T>);
// After:
// void Caller()
// {
// Print(typeof<int>);
// }
// void Callee<T>() => Print(typeof<int>);
// 2. Literal replacement
// Example:
// Before:
// void Caller()
// {
// Callee(20)
// }
// void Callee(int i, int j = 10)
// {
// Bar(i, j);
// }
// After:
// void Caller()
// {
// Bar(20, 10);
// }
// void Callee(int i, int j = 10)
// {
// Bar(i, j);
// }
// 3. Identifier
// Example:
// Before:
// void Caller()
// {
// int a, b, c;
// Callee(a, b)
// }
// void Callee(int i, int j)
// {
// Bar(i, j, out int c);
// }
// After:
// void Caller()
// {
// int a, b, c;
// Bar(a, b, out int c1);
// }
// void Callee(int i, int j = 10)
// {
// Bar(i, j, out int c);
// }
var replacementTable = ComputeReplacementTable(
calleeMethodSymbol,
methodParametersInfo.ParametersWithVariableDeclarationArgument,
methodParametersInfo.ParametersToReplace,
syntaxGenerator,
renameTable);
var containsAwaitExpression = ContainsAwaitExpression(rawInlineExpression);
// Do the replacement work within the callee's body so that it can be inserted to the caller later.
inlineExpression = await ReplaceAllSyntaxNodesForSymbolAsync(
calleeDocument,
inlineExpression,
syntaxGenerator,
replacementTable,
cancellationToken).ConfigureAwait(false);
return new InlineMethodContext(
localDeclarationStatementsNeedInsert,
inlineExpression,
containsAwaitExpression);
}
private static ImmutableArray<TStatementSyntax> GetLocalDeclarationStatementsNeedInsert(
SyntaxGenerator syntaxGenerator,
ImmutableArray<(IParameterSymbol parameterSymbol, TExpressionSyntax expression)> parametersToGenerateFreshVariablesFor,
ImmutableArray<(IParameterSymbol parameterSymbol, string identifierName)> parametersWithVariableDeclarationArgument,
ImmutableDictionary<ISymbol, string> renameTable)
{
var declarationsQuery = parametersToGenerateFreshVariablesFor
.Select(parameterAndArguments => CreateLocalDeclarationStatement(syntaxGenerator, renameTable, parameterAndArguments));
var declarationsForVariableDeclarationArgumentQuery = parametersWithVariableDeclarationArgument
.Select(parameterAndName =>
(TStatementSyntax)syntaxGenerator.LocalDeclarationStatement(
parameterAndName.parameterSymbol.Type,
parameterAndName.identifierName));
return declarationsQuery.Concat(declarationsForVariableDeclarationArgumentQuery).ToImmutableArray();
}
private bool ContainsAwaitExpression(TExpressionSyntax inlineExpression)
{
// Check if there is await expression. It is used later if the caller should be changed to async
var awaitExpressions = inlineExpression
.DescendantNodesAndSelf(node => !_syntaxFacts.IsAnonymousFunctionExpression(node))
.Where(_syntaxFacts.IsAwaitExpression)
.ToImmutableArray();
return !awaitExpressions.IsEmpty;
}
private static TStatementSyntax CreateLocalDeclarationStatement(
SyntaxGenerator syntaxGenerator,
ImmutableDictionary<ISymbol, string> renameTable,
(IParameterSymbol parameterSymbol, TExpressionSyntax expression) parameterAndExpression)
{
var (parameterSymbol, expression) = parameterAndExpression;
var name = renameTable.TryGetValue(parameterSymbol, out var newName) ? newName : parameterSymbol.Name;
return (TStatementSyntax)syntaxGenerator.LocalDeclarationStatement(parameterSymbol.Type, name, expression);
}
private static async Task<TExpressionSyntax> ReplaceAllSyntaxNodesForSymbolAsync(
Document document,
TExpressionSyntax inlineExpression,
SyntaxGenerator syntaxGenerator,
ImmutableDictionary<ISymbol, SyntaxNode> replacementTable,
CancellationToken cancellationToken)
{
var editor = new SyntaxEditor(inlineExpression, syntaxGenerator);
foreach (var (symbol, syntaxNode) in replacementTable)
{
var allReferences = await SymbolFinder
.FindReferencesAsync(symbol, document.Project.Solution, ImmutableHashSet<Document>.Empty.Add(document), cancellationToken)
.ConfigureAwait(false);
var allSyntaxNodesToReplace = allReferences
.SelectMany(reference => reference.Locations
.Where(location => !location.IsImplicit)
.Select(location => location.Location.FindNode(getInnermostNodeForTie: true, cancellationToken)))
.ToImmutableArray();
foreach (var nodeToReplace in allSyntaxNodesToReplace)
{
if (editor.OriginalRoot.Contains(nodeToReplace))
{
var replacementNodeWithTrivia = syntaxNode.WithTriviaFrom(nodeToReplace);
editor.ReplaceNode(nodeToReplace, replacementNodeWithTrivia);
}
}
}
return (TExpressionSyntax)editor.GetChangedRoot();
}
/// <summary>
/// Generate a dictionary which key is the symbol in Callee (include local variable and parameter), value
/// is the replacement syntax node for all its occurence.
/// </summary>
private ImmutableDictionary<ISymbol, SyntaxNode> ComputeReplacementTable(
IMethodSymbol calleeMethodSymbol,
ImmutableArray<(IParameterSymbol parameter, string identifierName)> parametersWithVariableDeclarationArgument,
ImmutableDictionary<IParameterSymbol, TExpressionSyntax> parametersToReplace,
SyntaxGenerator syntaxGenerator,
ImmutableDictionary<ISymbol, string> renameTable)
{
var typeParametersReplacementQuery = calleeMethodSymbol.TypeParameters
.Zip(calleeMethodSymbol.TypeArguments,
(parameter, argument) => (parameter: (ISymbol)parameter,
syntaxNode: GenerateTypeSyntax(argument, allowVar: true)));
var literalArgumentReplacementQuery = parametersToReplace
.Select(parameterAndExpressionPair => (parameter: (ISymbol)parameterAndExpressionPair.Key,
syntaxNode: (SyntaxNode)parameterAndExpressionPair.Value));
var parametersWithVariableDeclarationArgumentQuery = parametersWithVariableDeclarationArgument
.Select(parameterAndName => (parameter: (ISymbol)parameterAndName.parameter,
syntaxNode: syntaxGenerator.IdentifierName(parameterAndName.identifierName)));
var parametersNeedRenameQuery = renameTable
.Select(kvp => (parameter: kvp.Key, syntaxNode: syntaxGenerator.IdentifierName(kvp.Value)));
return parametersNeedRenameQuery
.Concat(parametersWithVariableDeclarationArgumentQuery)
.Concat(typeParametersReplacementQuery)
.Concat(literalArgumentReplacementQuery)
.ToImmutableDictionary(tuple => tuple.parameter, tuple => tuple.syntaxNode);
}
private static ImmutableDictionary<ISymbol, string> ComputeRenameTable(
ISemanticFactsService semanticFacts,
SemanticModel callerSemanticModel,
SemanticModel calleeSemanticModel,
SyntaxNode calleeInvocationNode,
TExpressionSyntax rawInlineExpression,
ImmutableArray<IParameterSymbol> parametersNeedGenerateFreshVariableFor,
CancellationToken cancellationToken)
{
var renameTable = new Dictionary<ISymbol, string>();
var localSymbolsInCallee = LocalVariableDeclarationVisitor
.GetAllSymbols(calleeSemanticModel, rawInlineExpression, cancellationToken);
foreach (var symbol in parametersNeedGenerateFreshVariableFor.Concat(localSymbolsInCallee))
{
var usedNames = renameTable.Values;
renameTable[symbol] = semanticFacts
.GenerateUniqueLocalName(
callerSemanticModel,
calleeInvocationNode,
container: null,
symbol.Name,
usedNames,
cancellationToken).Text;
}
return renameTable.ToImmutableDictionary();
}
private class LocalVariableDeclarationVisitor : OperationWalker
{
private readonly CancellationToken _cancellationToken;
private readonly HashSet<ISymbol> _allSymbols = [];
private LocalVariableDeclarationVisitor(CancellationToken cancellationToken)
{
_cancellationToken = cancellationToken;
}
public static ImmutableHashSet<ISymbol> GetAllSymbols(
SemanticModel semanticModel,
TExpressionSyntax methodDeclarationSyntax,
CancellationToken cancellationToken)
{
var visitor = new LocalVariableDeclarationVisitor(cancellationToken);
var operation = semanticModel.GetOperation(methodDeclarationSyntax, cancellationToken);
visitor.Visit(operation);
return [.. visitor._allSymbols];
}
public override void Visit(IOperation? operation)
{
_cancellationToken.ThrowIfCancellationRequested();
if (operation == null)
{
return;
}
if (operation is IVariableDeclaratorOperation variableDeclarationOperation)
{
_allSymbols.Add(variableDeclarationOperation.Symbol);
}
if (operation is ILocalReferenceOperation localReferenceOperation
&& localReferenceOperation.IsDeclaration)
{
_allSymbols.Add(localReferenceOperation.Local);
}
// Stop when meet lambda or local function
if (operation.Kind is OperationKind.AnonymousFunction or OperationKind.LocalFunction)
{
return;
}
base.Visit(operation);
}
}
}
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