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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.
using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Diagnostics;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using static Microsoft.CodeAnalysis.CSharp.SyntaxFactory;
namespace Microsoft.Interop
{
internal sealed class UnmanagedToManagedStubGenerator
{
private const string ReturnIdentifier = "__retVal";
private readonly BoundGenerators _marshallers;
private readonly StubIdentifierContext _context;
public UnmanagedToManagedStubGenerator(
ImmutableArray<TypePositionInfo> argTypes,
GeneratorDiagnosticsBag diagnosticsBag,
IMarshallingGeneratorResolver generatorResolver)
{
_marshallers = BoundGenerators.Create(argTypes, generatorResolver, StubCodeContext.DefaultNativeToManagedStub, new Forwarder(), out var bindingDiagnostics);
diagnosticsBag.ReportGeneratorDiagnostics(bindingDiagnostics);
if (_marshallers.NativeReturnMarshaller.UsesNativeIdentifier)
{
// If we need a different native return identifier, then recreate the context with the correct identifier before we generate any code.
_context = new DefaultIdentifierContext(ReturnIdentifier, $"{ReturnIdentifier}{StubIdentifierContext.GeneratedNativeIdentifierSuffix}", MarshalDirection.UnmanagedToManaged);
}
else
{
_context = new DefaultIdentifierContext(ReturnIdentifier, ReturnIdentifier, MarshalDirection.UnmanagedToManaged);
}
}
/// <summary>
/// Generate the method body of the unmanaged-to-managed ComWrappers-based method stub.
/// </summary>
/// <param name="methodToInvoke">Name of the method on the managed type to invoke</param>
/// <returns>Method body of the stub</returns>
/// <remarks>
/// The generated code assumes it will be in an unsafe context.
/// </remarks>
public BlockSyntax GenerateStubBody(ExpressionSyntax methodToInvoke)
{
GeneratedStatements statements = GeneratedStatements.Create(
_marshallers,
StubCodeContext.DefaultNativeToManagedStub,
_context, methodToInvoke);
Debug.Assert(statements.CleanupCalleeAllocated.IsEmpty);
bool shouldInitializeVariables =
!statements.GuaranteedUnmarshal.IsEmpty
|| !statements.CleanupCallerAllocated.IsEmpty
|| !statements.ManagedExceptionCatchClauses.IsEmpty;
VariableDeclarations declarations = VariableDeclarations.GenerateDeclarationsForUnmanagedToManaged(_marshallers, _context, shouldInitializeVariables);
List<StatementSyntax> setupStatements =
[
.. declarations.Initializations,
.. declarations.Variables,
.. statements.Setup,
];
List<StatementSyntax> tryStatements =
[
.. statements.GuaranteedUnmarshal,
.. statements.Unmarshal,
statements.InvokeStatement,
.. statements.NotifyForSuccessfulInvoke,
.. statements.Marshal,
.. statements.PinnedMarshal,
];
List<StatementSyntax> allStatements = setupStatements;
SyntaxList<CatchClauseSyntax> catchClauses = List(statements.ManagedExceptionCatchClauses);
ImmutableArray<StatementSyntax> finallyStatements = statements.CleanupCallerAllocated;
if (finallyStatements.Length > 0)
{
allStatements.Add(
TryStatement(Block(tryStatements), catchClauses, FinallyClause(Block(finallyStatements))));
}
else if (catchClauses.Count > 0)
{
allStatements.Add(
TryStatement(Block(tryStatements), catchClauses, @finally: null));
}
else
{
allStatements.AddRange(tryStatements);
}
// Return
if (!_marshallers.IsUnmanagedVoidReturn)
allStatements.Add(ReturnStatement(IdentifierName(_context.GetIdentifiers(_marshallers.NativeReturnMarshaller.TypeInfo).native)));
return Block(allStatements);
}
public (ParameterListSyntax ParameterList, TypeSyntax ReturnType, AttributeListSyntax? ReturnTypeAttributes) GenerateAbiMethodSignatureData()
{
return _marshallers.GenerateTargetMethodSignatureData(_context);
}
}
}
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