SortArgument GetSortArgumentFromSortCall(MethodCallExpression node)
{
if (node.Arguments[1].NodeType == ExpressionType.Quote)
{
UnaryExpression quote = (UnaryExpression)node.Arguments[1];
if (quote.Operand.NodeType == ExpressionType.Lambda)
{
LambdaExpression lambda = (LambdaExpression)quote.Operand;
if (lambda.Parameters.Count == 1)
{
SafeExpressionImporter importer = new SafeExpressionImporter(lambda.Parameters[0]);
Expression imported = importer.Import(lambda.Body);
if (imported != null)
{
return(new SortArgument(
Expression.Lambda(imported, lambda.Parameters[0]),
IsGenericMethodInfoOfCallTreeNode(node, KnownMembers.Queryable_OrderByDesc) ||
IsGenericMethodInfoOfCallTreeNode(node, KnownMembers.Queryable_ThenByDesc)
));
}
}
}
}
return(null);
}
SortArgument GetSortArgumentFromSortCall(MethodCallExpression node)
{
if (node.Arguments[1].NodeType == ExpressionType.Quote) {
UnaryExpression quote = (UnaryExpression)node.Arguments[1];
if (quote.Operand.NodeType == ExpressionType.Lambda) {
LambdaExpression lambda = (LambdaExpression)quote.Operand;
if (lambda.Parameters.Count == 1) {
SafeExpressionImporter importer = new SafeExpressionImporter(lambda.Parameters[0]);
Expression imported = importer.Import(lambda.Body);
if (imported != null)
return new SortArgument(
Expression.Lambda(imported, lambda.Parameters[0]),
IsGenericMethodInfoOfCallTreeNode(node, KnownMembers.Queryable_OrderByDesc)
|| IsGenericMethodInfoOfCallTreeNode(node, KnownMembers.Queryable_ThenByDesc)
);
}
}
}
return null;
}
protected override Expression VisitMethodCall(MethodCallExpression node)
{
if (node.Method == KnownMembers.QueryableOfCallTreeNode_Select && node.Arguments[1].NodeType == ExpressionType.Quote)
{
// CallTreeNode[].Select:
// selects are not supported by query evaluator, but we will detect and remove
// degenerate selects (.Select(x => x)).
UnaryExpression quote = (UnaryExpression)node.Arguments[1];
if (quote.Operand.NodeType == ExpressionType.Lambda)
{
LambdaExpression lambda = (LambdaExpression)quote.Operand;
if (lambda.Parameters.Count == 1 && lambda.Body == lambda.Parameters[0])
{
return(Visit(node.Arguments[0]));
}
}
}
else if (node.Method == KnownMembers.QueryableOfCallTreeNode_Where && node.Arguments[1].NodeType == ExpressionType.Quote)
{
// CallTreeNode[].Where:
// if the target is a QueryNode and the condition can be safely imported, convert the Where call to Filter
UnaryExpression quote = (UnaryExpression)node.Arguments[1];
if (quote.Operand.NodeType == ExpressionType.Lambda)
{
LambdaExpression lambda = (LambdaExpression)quote.Operand;
if (lambda.Parameters.Count == 1)
{
QueryNode target = Visit(node.Arguments[0]) as QueryNode;
if (target != null)
{
SafeExpressionImporter importer = new SafeExpressionImporter(lambda.Parameters[0]);
List <LambdaExpression> conditions = new List <LambdaExpression>();
if (importer.AddConditionsToFilterList(lambda.Body, conditions))
{
return(new Filter(target, conditions.ToArray()));
}
}
}
}
}
else if (node.Method == KnownMembers.Queryable_WithQueryLog && node.Arguments[1].NodeType == ExpressionType.Constant)
{
options.AddLogger((TextWriter)(((ConstantExpression)node.Arguments[1]).Value));
return(Visit(node.Arguments[0]));
}
else if (node.Method == KnownMembers.Queryable_MergeByName)
{
QueryNode target = Visit(node.Arguments[0]) as QueryNode;
if (target != null)
{
return(new MergeByName(target));
}
}
else if (node.Method == KnownMembers.QueryableOfCallTreeNode_Take && node.Arguments[1].NodeType == ExpressionType.Constant)
{
ConstantExpression ce = (ConstantExpression)node.Arguments[1];
if (ce.Type == typeof(int))
{
QueryNode target = Visit(node.Arguments[0]) as QueryNode;
if (target != null)
{
return(new Limit(target, 0, (int)ce.Value));
}
}
}
else if (IsGenericMethodInfoOfCallTreeNode(node, KnownMembers.Queryable_OrderBy) ||
IsGenericMethodInfoOfCallTreeNode(node, KnownMembers.Queryable_OrderByDesc))
{
SortArgument sortArgument = GetSortArgumentFromSortCall(node);
if (sortArgument != null)
{
QueryNode target = Visit(node.Arguments[0]) as QueryNode;
if (target != null)
{
return(new Sort(target, new [] { sortArgument }));
}
}
}
else if (IsThenByCall(node))
{
// 'ThenBy' is dangerous: we must not translate an OrderBy inside a ThenBy that we do not support
List <MethodCallExpression> thenByCalls = new List <MethodCallExpression>();
Expression tmp = node;
while (IsThenByCall(tmp))
{
thenByCalls.Add((MethodCallExpression)tmp);
tmp = ((MethodCallExpression)tmp).Arguments[0];
}
MethodCallExpression mc = tmp as MethodCallExpression;
if (mc != null &&
(IsGenericMethodInfoOfCallTreeNode(mc, KnownMembers.Queryable_OrderBy) ||
IsGenericMethodInfoOfCallTreeNode(mc, KnownMembers.Queryable_OrderByDesc)))
{
// TODO: add support for safe expressions in ThenBy
// this is an unsupported OrderBy/ThenBy sequence
// skip visiting the sequence and go directly into the base object
tmp = Visit(mc.Arguments[0]);
// now reconstruct the OrderBy/ThenBy sequence
tmp = Expression.Call(mc.Method, new[] { tmp }.Concat(mc.Arguments.Skip(1))); // reconstruct OrderBy
for (int i = thenByCalls.Count - 1; i >= 0; i--)
{
// reconstruct ThenBy
tmp = Expression.Call(thenByCalls[i].Method, new[] { tmp }.Concat(thenByCalls[i].Arguments.Skip(1)));
}
return(tmp);
}
// else: we couldn't detect the OrderBy belonging to this ThenBy; so it's probably not one
// of the OrderBy overloads that we support. Go down recursively
}
return(base.VisitMethodCall(node));
}
protected override Expression VisitMethodCall(MethodCallExpression node)
{
if (node.Method == KnownMembers.QueryableOfCallTreeNode_Select && node.Arguments[1].NodeType == ExpressionType.Quote) {
// CallTreeNode[].Select:
// selects are not supported by query evaluator, but we will detect and remove
// degenerate selects (.Select(x => x)).
UnaryExpression quote = (UnaryExpression)node.Arguments[1];
if (quote.Operand.NodeType == ExpressionType.Lambda) {
LambdaExpression lambda = (LambdaExpression)quote.Operand;
if (lambda.Parameters.Count == 1 && lambda.Body == lambda.Parameters[0])
return Visit(node.Arguments[0]);
}
} else if (node.Method == KnownMembers.QueryableOfCallTreeNode_Where && node.Arguments[1].NodeType == ExpressionType.Quote) {
// CallTreeNode[].Where:
// if the target is a QueryNode and the condition can be safely imported, convert the Where call to Filter
UnaryExpression quote = (UnaryExpression)node.Arguments[1];
if (quote.Operand.NodeType == ExpressionType.Lambda) {
LambdaExpression lambda = (LambdaExpression)quote.Operand;
if (lambda.Parameters.Count == 1) {
QueryNode target = Visit(node.Arguments[0]) as QueryNode;
if (target != null) {
SafeExpressionImporter importer = new SafeExpressionImporter(lambda.Parameters[0]);
List<LambdaExpression> conditions = new List<LambdaExpression>();
if (importer.AddConditionsToFilterList(lambda.Body, conditions)) {
return new Filter(target, conditions.ToArray());
}
}
}
}
} else if (node.Method == KnownMembers.Queryable_WithQueryLog && node.Arguments[1].NodeType == ExpressionType.Constant) {
options.AddLogger((TextWriter)(((ConstantExpression)node.Arguments[1]).Value));
return Visit(node.Arguments[0]);
} else if (node.Method == KnownMembers.Queryable_MergeByName) {
QueryNode target = Visit(node.Arguments[0]) as QueryNode;
if (target != null)
return new MergeByName(target);
} else if (node.Method == KnownMembers.QueryableOfCallTreeNode_Take && node.Arguments[1].NodeType == ExpressionType.Constant) {
ConstantExpression ce = (ConstantExpression)node.Arguments[1];
if (ce.Type == typeof(int)) {
QueryNode target = Visit(node.Arguments[0]) as QueryNode;
if (target != null) {
return new Limit(target, 0, (int)ce.Value);
}
}
} else if (IsGenericMethodInfoOfCallTreeNode(node, KnownMembers.Queryable_OrderBy) ||
IsGenericMethodInfoOfCallTreeNode(node, KnownMembers.Queryable_OrderByDesc)) {
SortArgument sortArgument = GetSortArgumentFromSortCall(node);
if (sortArgument != null) {
QueryNode target = Visit(node.Arguments[0]) as QueryNode;
if (target != null) {
return new Sort(target, new [] { sortArgument });
}
}
} else if (IsThenByCall(node)) {
// 'ThenBy' is dangerous: we must not translate an OrderBy inside a ThenBy that we do not support
List<MethodCallExpression> thenByCalls = new List<MethodCallExpression>();
Expression tmp = node;
while (IsThenByCall(tmp)) {
thenByCalls.Add((MethodCallExpression)tmp);
tmp = ((MethodCallExpression)tmp).Arguments[0];
}
MethodCallExpression mc = tmp as MethodCallExpression;
if (mc != null &&
(IsGenericMethodInfoOfCallTreeNode(mc, KnownMembers.Queryable_OrderBy) ||
IsGenericMethodInfoOfCallTreeNode(mc, KnownMembers.Queryable_OrderByDesc)))
{
// TODO: add support for safe expressions in ThenBy
// this is an unsupported OrderBy/ThenBy sequence
// skip visiting the sequence and go directly into the base object
tmp = Visit(mc.Arguments[0]);
// now reconstruct the OrderBy/ThenBy sequence
tmp = Expression.Call(mc.Method, new[] { tmp }.Concat(mc.Arguments.Skip(1))); // reconstruct OrderBy
for (int i = thenByCalls.Count - 1; i >= 0; i--) {
// reconstruct ThenBy
tmp = Expression.Call(thenByCalls[i].Method, new[] { tmp }.Concat(thenByCalls[i].Arguments.Skip(1)));
}
return tmp;
}
// else: we couldn't detect the OrderBy belonging to this ThenBy; so it's probably not one
// of the OrderBy overloads that we support. Go down recursively
}
return base.VisitMethodCall(node);
}
