public static IQueryProvider FindProvider(Expression expr)
{
var instance = new QueryProviderFinder();
instance.Visit(expr);
return(instance.queryProvider);
}
protected override Expression VisitMethodCall(MethodCallExpression node)
{
var declaringType = node.Method.DeclaringType;
if (declaringType == typeof(System.Linq.Enumerable) || declaringType == typeof(Queryable) ||
(declaringType.IsGenericType && declaringType.GetGenericTypeDefinition() == typeof(IQueryable <>)))
{
var provider = QueryProviderFinder.FindProvider(node);
if (provider != null)
{
var value = provider.Execute(node);
PushValue(value);
return(node);
}
}
var argValues = new object[node.Arguments.Count];
for (var i = 0; i < node.Arguments.Count; i++)
{
var arg = node.Arguments[i];
if (arg.NodeType == ExpressionType.Lambda)
{
var exp = ((LambdaExpression)arg);
Debug.Assert(exp.Parameters.Count == 1);
MethodInfo m;
var bf = BindingFlags.Static | BindingFlags.NonPublic;
var list = exp.Parameters.Select(o => o.Type).ToList();
list.Add(exp.Body.Type);
var types = list.ToArray();
switch (exp.Parameters.Count)
{
case 1:
m = this.GetType().GetMethod("CreateFunc1", bf)
.MakeGenericMethod(types);
break;
case 2:
m = this.GetType().GetMethod("CreateFunc2", bf)
.MakeGenericMethod(types);
break;
case 3:
m = this.GetType().GetMethod("CreateFunc3", bf)
.MakeGenericMethod(types);
break;
default:
throw new NotImplementedException();
}
argValues[i] = m.Invoke(null, new object[] { exp });
}
else
{
Visit(arg);
argValues[i] = this.PopValue();
}
}
if (node.Method.IsStatic)
{
var value = node.Method.Invoke(null, argValues);
PushValue(value);
}
else
{
Visit(node.Object);
var instance = PopValue();
Debug.Assert(instance != null);
var value = node.Method.Invoke(instance, argValues);
PushValue(value);
}
return(node);
}
public static IQueryProvider FindQueryProvider(Expression expr)
{
return(QueryProviderFinder.FindProvider(expr));
}
