bool HandleAnonymousMethod(ObjectCreateExpression objectCreateExpression, Expression target, MethodReference methodRef)
{
if (!context.Settings.AnonymousMethods)
{
return(false); // anonymous method decompilation is disabled
}
if (target != null && !(target is IdentifierExpression || target is ThisReferenceExpression || target is NullReferenceExpression))
{
return(false); // don't copy arbitrary expressions, deal with identifiers only
}
// Anonymous methods are defined in the same assembly
MethodDefinition method = methodRef.ResolveWithinSameModule();
if (!IsAnonymousMethod(context, method))
{
return(false);
}
// Create AnonymousMethodExpression and prepare parameters
AnonymousMethodExpression ame = new AnonymousMethodExpression();
ame.CopyAnnotationsFrom(objectCreateExpression); // copy ILRanges etc.
ame.RemoveAnnotations <MethodReference>(); // remove reference to delegate ctor
ame.AddAnnotation(method); // add reference to anonymous method
ame.Parameters.AddRange(AstBuilder.MakeParameters(method, isLambda: true));
ame.HasParameterList = true;
// rename variables so that they don't conflict with the parameters:
foreach (ParameterDeclaration pd in ame.Parameters)
{
EnsureVariableNameIsAvailable(objectCreateExpression, pd.Name);
}
// Decompile the anonymous method:
DecompilerContext subContext = context.Clone();
subContext.CurrentMethod = method;
subContext.CurrentMethodIsAsync = false;
subContext.ReservedVariableNames.AddRange(currentlyUsedVariableNames);
BlockStatement body = AstMethodBodyBuilder.CreateMethodBody(method, subContext, ame.Parameters);
TransformationPipeline.RunTransformationsUntil(body,
v => v is DelegateConstruction,
subContext);
body.AcceptVisitor(this, null);
bool isLambda = false;
if (ame.Parameters.All(p => p.ParameterModifier == ParameterModifier.None))
{
isLambda = (body.Statements.Count == 1 && body.Statements.Single() is ReturnStatement);
}
// Remove the parameter list from an AnonymousMethodExpression if the original method had no names,
// and the parameters are not used in the method body
if (!isLambda && method.Parameters.All(p => string.IsNullOrEmpty(p.Name)))
{
var parameterReferencingIdentifiers =
from ident in body.Descendants.OfType <IdentifierExpression>()
let v = ident.Annotation <ILVariable>()
where v != null && v.IsParameter && method.Parameters.Contains(v.OriginalParameter)
select ident;
if (!parameterReferencingIdentifiers.Any())
{
ame.Parameters.Clear();
ame.HasParameterList = false;
}
}
// Replace all occurrences of 'this' in the method body with the delegate's target:
foreach (AstNode node in body.Descendants)
{
if (node is ThisReferenceExpression)
{
node.ReplaceWith(target.Clone());
}
}
Expression replacement;
if (isLambda)
{
LambdaExpression lambda = new LambdaExpression();
lambda.CopyAnnotationsFrom(ame);
ame.Parameters.MoveTo(lambda.Parameters);
Expression returnExpr = ((ReturnStatement)body.Statements.Single()).Expression;
returnExpr.Remove();
lambda.Body = returnExpr;
replacement = lambda;
}
else
{
ame.Body = body;
replacement = ame;
}
var expectedType = objectCreateExpression.Annotation <TypeInformation>().ExpectedType.Resolve();
if (expectedType != null && !expectedType.IsDelegate())
{
var simplifiedDelegateCreation = (ObjectCreateExpression)objectCreateExpression.Clone();
simplifiedDelegateCreation.Arguments.Clear();
simplifiedDelegateCreation.Arguments.Add(replacement);
replacement = simplifiedDelegateCreation;
}
objectCreateExpression.ReplaceWith(replacement);
return(true);
}