private static Func <InternalEntityEntry, TProperty> CreateCurrentValueGetter <TProperty>(
IPropertyBase propertyBase, bool useStoreGeneratedValues)
{
var entityClrType = propertyBase.DeclaringType.ClrType;
var entryParameter = Expression.Parameter(typeof(InternalEntityEntry), "entry");
var shadowIndex = propertyBase.GetShadowIndex();
Expression currentValueExpression;
if (shadowIndex >= 0)
{
currentValueExpression = Expression.Call(
entryParameter,
InternalEntityEntry.ReadShadowValueMethod.MakeGenericMethod(typeof(TProperty)),
Expression.Constant(shadowIndex));
}
else
{
var convertedExpression = Expression.Convert(
Expression.Property(entryParameter, "Entity"),
entityClrType);
if (propertyBase.IsIndexedProperty())
{
currentValueExpression = Expression.MakeIndex(
convertedExpression,
propertyBase.PropertyInfo,
new [] { Expression.Constant(propertyBase.Name) });
}
else
{
currentValueExpression = Expression.MakeMemberAccess(
convertedExpression,
propertyBase.GetMemberInfo(forConstruction: false, forSet: false));
}
if (currentValueExpression.Type != typeof(TProperty))
{
currentValueExpression = Expression.Convert(currentValueExpression, typeof(TProperty));
}
}
var storeGeneratedIndex = propertyBase.GetStoreGeneratedIndex();
if (storeGeneratedIndex >= 0)
{
if (useStoreGeneratedValues)
{
currentValueExpression = Expression.Condition(
Expression.Equal(
currentValueExpression,
Expression.Constant(default(TProperty), typeof(TProperty))),
Expression.Call(
entryParameter,
InternalEntityEntry.ReadStoreGeneratedValueMethod.MakeGenericMethod(typeof(TProperty)),
Expression.Constant(storeGeneratedIndex)),
currentValueExpression);
}
currentValueExpression = Expression.Condition(
Expression.Equal(
currentValueExpression,
Expression.Constant(default(TProperty), typeof(TProperty))),
Expression.Call(
entryParameter,
InternalEntityEntry.ReadTemporaryValueMethod.MakeGenericMethod(typeof(TProperty)),
Expression.Constant(storeGeneratedIndex)),
currentValueExpression);
}
return(Expression.Lambda <Func <InternalEntityEntry, TProperty> >(
currentValueExpression,
entryParameter)
.Compile());
}