implemented the first version of statement_cache

include/matador/sql/interface/statement_proxy.hpp

@@ -0,0 +1,37 @@
+#ifndef STATEMENT_PROXY_HPP
+#define STATEMENT_PROXY_HPP
+
+#include "matador/sql/interface/statement_impl.hpp"
+
+namespace matador::sql {
+class statement_proxy {
+protected:
+  explicit statement_proxy(std::unique_ptr<statement_impl>&& stmt);
+
+public:
+  virtual ~statement_proxy() = default;
+
+  virtual utils::result<size_t, utils::error> execute() = 0;
+  virtual utils::result<std::unique_ptr<query_result_impl>, utils::error> fetch() = 0;
+
+  template<class Type>
+  void bind(const Type &obj) {
+    statement_->bind_object(obj);
+  }
+  template<typename Type>
+  void bind(size_t pos, Type &value) {
+    statement_->bind(pos, value);
+  }
+  void bind(size_t pos, const char *value, size_t size) const;
+  void bind(size_t pos, std::string &val, size_t size) const;
+
+  void reset() const;
+
+protected:
+  std::unique_ptr<statement_impl> statement_;
+};
+
+
+}
+
+#endif //STATEMENT_PROXY_HPP