private Expression MaterializeObject(Expression visited)
{
if (depth > 0 && !extraProperties)
{
return(SqlServerJsonValueReader.CreateReadComplexPropertyExpression(
visited.Type,
jsonTextReader,
GetNameParts().LastOrDefault(),
Expression.Lambda(
visited,
GetMaterializerName(),
Array.Empty <ParameterExpression>())));
}
return(visited);
}
protected override Expression VisitLeaf(Expression node)
{
if (node.Type.IsScalarType())
{
var sqlColumnExpression = node as SqlColumnExpression;
var typeMapping = sqlColumnExpression?.TypeMapping ?? typeMappingProvider.FindMapping(node.Type);
if (typeMapping?.TargetConversion is null)
{
return(SqlServerJsonValueReader.CreateReadScalarExpression(
node.Type,
jsonTextReader,
GetNameParts().Last()));
}
var result
= SqlServerJsonValueReader.CreateReadScalarExpression(
typeMapping.SourceType,
jsonTextReader,
GetNameParts().Last());
var mappingParameter = typeMapping.TargetConversion.Parameters.Single();
result
= Expression.Block(
variables: new[] { mappingParameter },
expressions: new Expression[]
{
Expression.Assign(mappingParameter, result),
Expression.Convert(typeMapping.TargetConversion.Body, node.Type),
});
return(result);
}
else if (node.Type.IsSequenceType())
{
var sequenceType = node.Type.GetSequenceType();
var extracted = ExtractProjectionExpression(node);
Expression materializer;
if (sequenceType.IsScalarType())
{
// TODO: Get rid of the need to put this constant multiple places.
var name = "$c";
switch (extracted)
{
case SqlColumnExpression sqlColumnExpression:
{
name = sqlColumnExpression.ColumnName;
break;
}
case SqlAliasExpression sqlAliasExpression:
{
name = sqlAliasExpression.Alias;
break;
}
}
materializer = SqlServerJsonValueReader.CreateReadScalarExpression(sequenceType, jsonTextReader, name);
}
else
{
if (extracted == node)
{
return(SqlServerJsonValueReader.CreateReadOpaqueObjectExpression(node.Type, jsonTextReader));
}
var visitor = new ComplexTypeMaterializerBuildingExpressionVisitor(jsonTextReader, typeMappingProvider);
materializer = visitor.Visit(extracted);
}
return(CreateSequenceExpression(
SqlServerJsonValueReader.CreateReadArrayExpression(
sequenceType,
jsonTextReader,
GetNameParts().LastOrDefault(),
Expression.Lambda(
materializer,
GetMaterializerName(),
Array.Empty <ParameterExpression>())),
node.Type));
}
else
{
var extracted = ExtractProjectionExpression(node);
if (extracted == node)
{
return(SqlServerJsonValueReader.CreateReadOpaqueObjectExpression(node.Type, jsonTextReader));
}
var visitor = new ComplexTypeMaterializerBuildingExpressionVisitor(jsonTextReader, typeMappingProvider);
var result = visitor.Visit(extracted);
if (result is MethodCallExpression call &&
call.Method.DeclaringType == typeof(SqlServerJsonValueReader))
{
return(result);
}
return(SqlServerJsonValueReader.CreateReadComplexObjectExpression(
node.Type,
jsonTextReader,
Expression.Lambda(
result,
GetMaterializerName(),
Array.Empty <ParameterExpression>())));
}
}