private Action <object, object> GenerateSetter(MaterializerPathInfo pathInfo)
{
var targetParameter = Expression.Parameter(typeof(object));
var valueParameter = Expression.Parameter(typeof(object));
var currentExpression = (Expression)targetParameter;
var lastMember = default(MemberInfo);
for (var i = 0; i < pathInfo.Path.Length; i++)
{
var member = pathInfo.Path[i];
if (!member.DeclaringType.IsAssignableFrom(currentExpression.Type))
{
currentExpression = Expression.Convert(currentExpression, member.DeclaringType);
}
if (i + 1 == pathInfo.Path.Length)
{
currentExpression = Expression.MakeMemberAccess(currentExpression, member = GetMemberForWrite(member));
}
else
{
currentExpression = Expression.MakeMemberAccess(currentExpression, member = GetMemberForRead(member));
}
lastMember = member;
}
Expression body = default;
if (lastMember is FieldInfo field && field.IsInitOnly)
{
body
= Expression.Call(
Expression.Constant(field),
typeof(FieldInfo).GetRuntimeMethod(nameof(FieldInfo.SetValue), new[] { typeof(object), typeof(object) }),
(currentExpression as MemberExpression).Expression,
Expression.Convert(valueParameter, currentExpression.Type));
}
private Func <object, object> GenerateGetter(MaterializerPathInfo pathInfo)
{
var blockVariables = new List <ParameterExpression>();
var blockExpressions = new List <Expression>();
var parameter = Expression.Parameter(typeof(object));
var currentExpression = (Expression)parameter;
var returnLabel = Expression.Label(typeof(object), "Return");
var nullConstantExpression = Expression.Constant(null, typeof(object));
for (var i = 0; i < pathInfo.Path.Length; i++)
{
var member = pathInfo.Path[i];
var memberType = member.GetMemberType();
var memberVariable = Expression.Variable(memberType, member.Name);
blockVariables.Add(memberVariable);
/*if (member.DeclaringType.IsGenericType(typeof(ExpandedGrouping<,>)))
* {
* Debug.Assert(member == pathInfo.Path.Last());
*
* if (member.Name == "Elements")
* {
* blockExpressions.Add(
* Expression.IfThen(
* Expression.Not(Expression.TypeIs(currentExpression, member.DeclaringType)),
* Expression.Return(returnLabel, currentExpression)));
* }
* else
* {
* member = member.DeclaringType.FindGenericType(typeof(IGrouping<,>)).GetRuntimeProperty("Key");
* }
* }*/
if (!member.DeclaringType.IsAssignableFrom(currentExpression.Type))
{
currentExpression = Expression.TypeAs(currentExpression, member.DeclaringType);
}
blockExpressions.Add(
Expression.IfThen(
Expression.Equal(nullConstantExpression, currentExpression),
Expression.Return(returnLabel, Expression.Default(memberType))));
blockExpressions.Add(
Expression.Assign(
memberVariable,
Expression.MakeMemberAccess(currentExpression, GetMemberForRead(member))));
currentExpression = memberVariable;
}
blockExpressions.Add(Expression.Label(returnLabel, currentExpression));
return(Expression
.Lambda <Func <object, object> >(
Expression.Block(blockVariables, blockExpressions),
parameter)
.Compile());
}
