private static SqlExpression Recurse(ref int i, bool useCompression, bool useSingleTable, Expression expression, bool isUnary = false, string prefix = null, string postfix = null)
{
if (expression is UnaryExpression unary)
{
return(SqlExpression.Concat(unary.NodeType.ToSqlString(), Recurse(ref i, useCompression, useSingleTable, unary.Operand, true)));
}
if (expression is BinaryExpression body)
{
return(SqlExpression.Concat(Recurse(ref i, useCompression, useSingleTable, body.Left), body.NodeType.ToSqlString(), Recurse(ref i, useCompression, useSingleTable, body.Right)));
}
if (expression is ConstantExpression constant)
{
var value = constant.Value;
if (value is int)
{
return(SqlExpression.TextOnly(value.ToString()));
}
if (value is string)
{
value = prefix + (string)value + postfix;
}
if (value is bool && isUnary)
{
return(SqlExpression.Concat(SqlExpression.WithSingleParameter(i++, value), "=", SqlExpression.TextOnly("1")));
}
return(SqlExpression.WithSingleParameter(i++, value));
}
if (expression is MemberExpression member)
{
var value = TryGetMemberValue(member);
if (value != null)
{
return(GetMemberValue(ref i, value, prefix, postfix));
}
if (member.Member is PropertyInfo property)
{
if (isUnary && member.Type == typeof(bool))
{
return(SqlExpression.Concat(Recurse(ref i, useCompression, useSingleTable, expression), "=", SqlExpression.WithSingleParameter(i++, true)));
}
var name = expression.ToString();
if (name.Contains('.'))
{
name = string.Join(".", name.Split('.').Skip(1));
}
name = TableHelper.GetFixedLeftPart(name, useCompression, useSingleTable);
return(SqlExpression.TextOnly(name));
}
if (member.Member is FieldInfo)
{
value = TryGetMemberValue(member);
return(GetMemberValue(ref i, value, prefix, postfix));
}
throw new Exception($"Expression does not refer to a property or field: {expression}");
}
if (expression is MethodCallExpression methodCall)
{
// LIKE queries:
if (methodCall.Method == typeof(string).GetMethod(nameof(string.Contains), new[] { typeof(string) }))
{
return(SqlExpression.Concat(Recurse(ref i, useCompression, useSingleTable, methodCall.Object), "LIKE", Recurse(ref i, useCompression, useSingleTable, methodCall.Arguments[0], prefix: "%", postfix: "%")));
}
if (methodCall.Method == typeof(string).GetMethod(nameof(string.StartsWith), new[] { typeof(string) }))
{
return(SqlExpression.Concat(Recurse(ref i, useCompression, useSingleTable, methodCall.Object), "LIKE", Recurse(ref i, useCompression, useSingleTable, methodCall.Arguments[0], postfix: "%")));
}
if (methodCall.Method == typeof(string).GetMethod(nameof(string.EndsWith), new[] { typeof(string) }))
{
return(SqlExpression.Concat(Recurse(ref i, useCompression, useSingleTable, methodCall.Object), "LIKE", Recurse(ref i, useCompression, useSingleTable, methodCall.Arguments[0], prefix: "%")));
}
// IN queries:
if (methodCall.Method.Name == nameof(IList.Contains))
{
Expression collection;
Expression property;
if (methodCall.Method.IsDefined(typeof(ExtensionAttribute)) && methodCall.Arguments.Count == 2)
{
collection = methodCall.Arguments[0];
property = methodCall.Arguments[1];
}
else if (!methodCall.Method.IsDefined(typeof(ExtensionAttribute)) && methodCall.Arguments.Count == 1)
{
collection = methodCall.Object;
property = methodCall.Arguments[0];
}
else
{
throw new Exception("Unsupported method call: " + methodCall.Method.Name);
}
var values = (IEnumerable)GetValue(collection);
return(SqlExpression.Concat(Recurse(ref i, useCompression, useSingleTable, property), "IN", SqlExpression.WithParameters(ref i, values)));
}
throw new Exception("Unsupported method call: " + methodCall.Method.Name);
}
throw new Exception("Unsupported expression: " + expression.GetType().Name);
}