private (Expression Operand, NavigationExpansionExpressionState State) ApplyIncludes(
NavigationExpansionExpression navigationExpansionExpression)
{
var includeVisitor = new PendingSelectorIncludeVisitor();
var rewrittenBody = includeVisitor.Visit(navigationExpansionExpression.State.PendingSelector.Body);
if (navigationExpansionExpression.State.PendingSelector.Body != rewrittenBody)
{
navigationExpansionExpression.State.PendingSelector = Expression.Lambda(rewrittenBody, navigationExpansionExpression.State.PendingSelector.Parameters[0]);
navigationExpansionExpression.State.ApplyPendingSelector = true;
}
if (includeVisitor.PendingIncludes.Count > 0)
{
var result = (Source : navigationExpansionExpression.Operand, Parameter : navigationExpansionExpression.State.CurrentParameter);
foreach (var pendingIncludeNode in includeVisitor.PendingIncludes)
{
result = NavigationExpansionHelpers.AddNavigationJoin(
result.Source,
result.Parameter,
pendingIncludeNode.SourceMapping,
pendingIncludeNode.NavTreeNode,
navigationExpansionExpression.State,
new List <INavigation>(),
include: true);
}
var pendingSelector = navigationExpansionExpression.State.PendingSelector;
if (navigationExpansionExpression.State.CurrentParameter != result.Parameter)
{
var pendingSelectorBody = new ExpressionReplacingVisitor(navigationExpansionExpression.State.CurrentParameter, result.Parameter).Visit(navigationExpansionExpression.State.PendingSelector.Body);
pendingSelector = Expression.Lambda(pendingSelectorBody, result.Parameter);
}
var newState = new NavigationExpansionExpressionState(
result.Parameter,
navigationExpansionExpression.State.SourceMappings,
pendingSelector,
applyPendingSelector: true,
navigationExpansionExpression.State.PendingOrderings,
navigationExpansionExpression.State.PendingIncludeChain,
navigationExpansionExpression.State.PendingCardinalityReducingOperator,
navigationExpansionExpression.State.CustomRootMappings,
navigationExpansionExpression.State.MaterializeCollectionNavigation);
return(Operand : result.Source, newState);
}
return(navigationExpansionExpression.Operand, navigationExpansionExpression.State);
}
protected override Expression VisitExtension(Expression extensionExpression)
{
switch (extensionExpression)
{
case NavigationBindingExpression navigationBindingExpression:
return(navigationBindingExpression.RootParameter.BuildPropertyAccess(
navigationBindingExpression.NavigationTreeNode.ToMapping));
case NavigationExpansionRootExpression navigationExpansionRootExpression:
return(Visit(navigationExpansionRootExpression.Unwrap()));
case NavigationExpansionExpression navigationExpansionExpression:
{
var(result, state) = ApplyIncludes(navigationExpansionExpression);
result = Visit(result);
if (!state.ApplyPendingSelector &&
state.PendingOrderings.Count == 0 &&
state.PendingCardinalityReducingOperator == null &&
state.MaterializeCollectionNavigation == null)
{
return(result);
}
var parameterType = result.Type.GetSequenceType();
foreach (var pendingOrdering in state.PendingOrderings)
{
var remappedKeySelectorBody = new ExpressionReplacingVisitor(pendingOrdering.keySelector.Parameters[0], state.CurrentParameter).Visit(pendingOrdering.keySelector.Body);
var newSelectorBody = new NavigationPropertyUnbindingVisitor(state.CurrentParameter).Visit(remappedKeySelectorBody);
var newSelector = Expression.Lambda(newSelectorBody, state.CurrentParameter);
var orderingMethod = pendingOrdering.method.MakeGenericMethod(state.CurrentParameter.Type, newSelectorBody.Type);
result = Expression.Call(orderingMethod, result, newSelector);
}
if (state.ApplyPendingSelector)
{
var pendingSelector = (LambdaExpression) new NavigationPropertyUnbindingVisitor(state.CurrentParameter).Visit(state.PendingSelector);
var pendingSelectorBodyType = pendingSelector.Type.GetGenericArguments()[1];
var pendingSelectMethod = result.Type.IsGenericType && (result.Type.GetGenericTypeDefinition() == typeof(IEnumerable <>) || result.Type.GetGenericTypeDefinition() == typeof(IOrderedEnumerable <>))
? LinqMethodHelpers.EnumerableSelectMethodInfo.MakeGenericMethod(parameterType, pendingSelectorBodyType)
: LinqMethodHelpers.QueryableSelectMethodInfo.MakeGenericMethod(parameterType, pendingSelectorBodyType);
result = Expression.Call(pendingSelectMethod, result, pendingSelector);
parameterType = result.Type.GetSequenceType();
}
if (state.PendingCardinalityReducingOperator != null)
{
result = Expression.Call(state.PendingCardinalityReducingOperator, result);
}
if (state.MaterializeCollectionNavigation != null)
{
result = new MaterializeCollectionNavigationExpression(result, state.MaterializeCollectionNavigation);
}
if (navigationExpansionExpression.Type != result.Type && navigationExpansionExpression.Type.IsGenericType)
{
if (navigationExpansionExpression.Type.GetGenericTypeDefinition() == typeof(IOrderedQueryable <>))
{
var toOrderedQueryableMethodInfo = ToOrderedQueryableMethod.MakeGenericMethod(parameterType);
return(Expression.Call(toOrderedQueryableMethodInfo, result));
}
if (navigationExpansionExpression.Type.GetGenericTypeDefinition() == typeof(IOrderedEnumerable <>))
{
var toOrderedEnumerableMethodInfo = ToOrderedEnumerableMethod.MakeGenericMethod(parameterType);
return(Expression.Call(toOrderedEnumerableMethodInfo, result));
}
}
return(result);
}
}
return(base.VisitExtension(extensionExpression));
}
