fieldDescriptor

Author: Pavel Siska

new-process-api/fieldDescriptor.hpp

@@ -0,0 +1,102 @@
+/**
+ * @file
+ * @author Pavel Siska <[email protected]>
+ * @brief Provides the FieldDescriptor class for accessing field metadata and value getters.
+ *
+ * This class encapsulates information about a field in a FlowRecord, including its
+ * name, group, bit index, and a generic value accessor. It allows checking if the
+ * field is present in a specific FlowRecord. Construction is restricted to FieldManager.
+ *
+ * @copyright Copyright (c) 2025 CESNET, z.s.p.o.
+ */
+
+#pragma once
+
+#include "fieldGenericValueGetter.hpp"
+#include "fieldInfo.hpp"
+#include "flowRecord.hpp"
+
+#include <cstdint>
+#include <string>
+#include <string_view>
+
+namespace ipxp {
+
+/**
+ * @class FieldDescriptor
+ * @brief Read-only access to field metadata and value getters.
+ *
+ * FieldDescriptor represents a single field within a FlowRecord. It provides
+ * information about the field's name, logical group, bit index, and a generic
+ * value accessor. It allows checking if the field is present in a specific
+ * FlowRecord using the `isInRecord()` method.
+ *
+ * Instances are immutable and can only be created by FieldManager, ensuring
+ * controlled registration and consistent state of fields.
+ */
+class FieldDescriptor {
+public:
+	/**
+	 * @brief Returns the name of the field.
+	 * @return Field name as string_view.
+	 */
+	[[nodiscard]]
+	std::string_view getName() const noexcept
+	{
+		return m_fieldInfo.name;
+	}
+
+	/**
+	 * @brief Returns the logical group name of the field.
+	 * @return Group name (e.g., "tcp", "http").
+	 */
+	[[nodiscard]]
+	std::string_view getGroup() const noexcept
+	{
+		return m_fieldInfo.group;
+	}
+
+	/**
+	 * @brief Returns the generic value accessor for the field.
+	 * @return Reference to GenericValueGetter variant.
+	 */
+	[[nodiscard]]
+	const GenericValueGetter& getValueGetter() const noexcept
+	{
+		return m_fieldInfo.getter;
+	}
+
+	/**
+	 * @brief Returns the bit index used to check field presence in FlowRecord.
+	 * @return Bit index as size_t.
+	 */
+	[[nodiscard]]
+	std::size_t getBitIndex() const noexcept
+	{
+		return m_fieldInfo.bitIndex;
+	}
+
+	/**
+	 * @brief Checks whether this field is present in a given FlowRecord.
+	 * @param record Flow record to query.
+	 * @return True if the field is available in the record.
+	 */
+	[[nodiscard]]
+	bool isInRecord(const FlowRecord& record) const
+	{
+		return record.fieldsAvailable.test(m_fieldInfo.bitIndex);
+	}
+
+private:
+	// FieldDescriptor can only be constructed by FieldManager
+	friend class FieldManager;
+
+	explicit FieldDescriptor(FieldInfo fieldInfo)
+		: m_fieldInfo(std::move(fieldInfo))
+	{
+	}
+
+	const FieldInfo m_fieldInfo;
+};
+
+} // namespace ipxp