1 files changed, 157 insertions, 0 deletions
diff --git a/agent/data/table/item.hpp b/agent/data/table/item.hpp
new file mode 100644
index 0000000..7c4c0eb
--- /dev/null
+++ b/agent/data/table/item.hpp
@@ -0,0 +1,157 @@
+/**
+ * @brief MIB tables item definition.
+ *
+ * This file is part of sila-snmp project.
+ *
+ * Copyright (c) 2022 SILA
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+#pragma once
+
+#include "sdbusplus/helper.hpp"
+
+namespace phosphor
+{
+namespace snmp
+{
+namespace data
+{
+namespace table
+{
+
+/**
+ * @brief MIB Table row implementation.
+ */
+template <typename... T> struct Item
+{
+    /*
+     * The `std::variant` allows to keep duplicates of types,
+     * but `std::get<>()` and `std::holds_alternative<>()` is ill-formed
+     * in this case.
+     *
+     * So we can't use here:
+     *   using variant_t = std::variant<T...>;
+     * and we should specify all possible types.
+     */
+    using variant_t = std::variant<int64_t, std::string, bool, uint8_t, double>;
+
+    using values_t = std::tuple<T...>;
+    using fields_map_t = std::map<std::string, variant_t>;
+
+    /* Define all of the basic class operations:
+     *     Not allowed:
+     *         - Default constructor to avoid nullptrs.
+     *         - Copy operations due to internal unique_ptr.
+     *     Allowed:
+     *         - Move operations.
+     *         - Destructor.
+     */
+    Item() = delete;
+    Item(const Item&) = delete;
+    Item& operator=(const Item&) = delete;
+    Item(Item&&) = default;
+    Item& operator=(Item&&) = default;
+    ~Item() = default;
+
+    /**
+     * @brief Object constructor
+     *
+     * @param folder - Base folder for DBus object path
+     * @param name - DBus object path relative by folder
+     * @param args - Default values for each fields
+     */
+    Item(const std::string& folder, const std::string& name, T&&... args) :
+        name(name), data(std::forward<T>(args)...),
+        changedMatch(sdbusplus::helper::helper::getBus(),
+                     sdbusplus::bus::match::rules::propertiesChanged(
+                         folder + "/" + name),
+                     std::bind(&Item<T...>::onPropertiesChanged, this,
+                               std::placeholders::_1))
+    {
+    }
+
+    /**
+     * @brief PropertiesChanged signal handler
+     */
+    virtual void onPropertiesChanged(sdbusplus::message::message& m)
+    {
+        std::string iface;
+        fields_map_t data;
+        std::vector<std::string> v;
+        m.read(iface, data, v);
+
+        setFields(data);
+    }
+
+    /**
+     * @brief Store fields values recieved from DBus
+     */
+    virtual void setFields(const fields_map_t& fields) = 0;
+
+    /**
+     * @brief Called after object has been created.
+     */
+    virtual void onCreate()
+    {
+    }
+
+    /**
+     * @brief Called before object will be destroyed.
+     */
+    virtual void onDestroy()
+    {
+    }
+
+    /**
+     * @brief String fields vlaues helper
+     */
+    template <size_t Index>
+    void setField(const fields_map_t& fieldsMap, const char* propertyName)
+    {
+        using FieldType = typename std::tuple_element<Index, values_t>::type;
+        if (fieldsMap.find(propertyName) != fieldsMap.end() &&
+            std::holds_alternative<FieldType>(fieldsMap.at(propertyName)))
+        {
+            std::get<Index>(data) =
+                std::get<FieldType>(fieldsMap.at(propertyName));
+        }
+    }
+
+    /**
+     * @brief Fill snmp reply with fields values
+     */
+    virtual void get_snmp_reply(netsnmp_agent_request_info* reqinfo,
+                                netsnmp_request_info* request) const = 0;
+
+    std::string name;
+    values_t data;
+
+  private:
+    sdbusplus::bus::match::match changedMatch;
+};
+
+/**
+ * @brief Used for std::lower_bound throw vector of smartpointers.
+ */
+template <typename ItemType>
+inline bool operator<(const std::unique_ptr<ItemType>& o, const std::string& s)
+{
+    return o->name < s;
+}
+
+} // namespace table
+} // namespace data
+} // namespace snmp
+} // namespace phosphor