New cpp folder structure

Signed-off-by: Alexander Borsuk <me@alex.bio>

libs/indexer/drules_selector_parser.hpp

@@ -0,0 +1,48 @@
+#pragma once
+
+#include <string>
+
+namespace drule
+{
+
+enum SelectorOperatorType
+{
+  SelectorOperatorUnknown = 0,
+
+  // [tag!=value]
+  SelectorOperatorNotEqual,
+
+  // [tag<=value]
+  SelectorOperatorLessOrEqual,
+
+  // [tag>=value]
+  SelectorOperatorGreaterOrEqual,
+
+  // [tag=value]
+  SelectorOperatorEqual,
+
+  // [tag<value]
+  SelectorOperatorLess,
+
+  // [tag>value]
+  SelectorOperatorGreater,
+
+  // [!tag]
+  SelectorOperatorIsNotSet,
+
+  // [tag]
+  SelectorOperatorIsSet,
+};
+
+struct SelectorExpression
+{
+  SelectorOperatorType m_operator;
+  std::string m_tag;
+  std::string m_value;
+
+  SelectorExpression() : m_operator(SelectorOperatorUnknown) {}
+};
+
+bool ParseSelector(std::string const & str, SelectorExpression & e);
+
+}  // namespace drule