From 0f4556fc2343dc0ade0bb1e0d1fc6f85770d77af Mon Sep 17 00:00:00 2001
From: "Andrey V.Kosteltsev" <AKosteltsev@IBS.RU>
Date: Fri, 15 Jul 2022 10:36:51 +0300
Subject: First commit: Sila SNMP Sub Agent and configuration manager

---
 sdbusplus/helper.hpp | 168 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 168 insertions(+)
 create mode 100644 sdbusplus/helper.hpp

(limited to 'sdbusplus')

diff --git a/sdbusplus/helper.hpp b/sdbusplus/helper.hpp
new file mode 100644
index 0000000..512eada
--- /dev/null
+++ b/sdbusplus/helper.hpp
@@ -0,0 +1,168 @@
+/**
+ * @brief sdbusplus library helper
+ *
+ * This file is part of sila-snmp-agent 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/bus.hpp>
+#include <sdbusplus/message.hpp>
+#include <sdbusplus/bus/match.hpp>
+#include <sdbusplus/exception.hpp>
+
+namespace sdbusplus
+{
+namespace helper
+{
+
+constexpr auto OBJECT_MAPPER_IFACE = "xyz.openbmc_project.ObjectMapper";
+constexpr auto OBJECT_MAPPER_PATH = "/xyz/openbmc_project/object_mapper";
+constexpr auto PROPERTIES_IFACE = "org.freedesktop.DBus.Properties";
+
+struct helper
+{
+    static auto& getBus()
+    {
+        static auto bus = sdbusplus::bus::new_system();
+        return bus;
+    }
+
+    /** @brief Invoke a method. */
+    template <typename... Args>
+    static auto callMethod(const std::string& busName, const std::string& path,
+                           const std::string& interface,
+                           const std::string& method, Args&&... args)
+    {
+        auto reqMsg = getBus().new_method_call(
+            busName.c_str(), path.c_str(), interface.c_str(), method.c_str());
+        reqMsg.append(std::forward<Args>(args)...);
+        return getBus().call(reqMsg);
+    }
+
+    /** @brief Invoke a method and read the response. */
+    template <typename Ret, typename... Args>
+    static Ret callMethodAndRead(const std::string& busName,
+                                 const std::string& path,
+                                 const std::string& interface,
+                                 const std::string& method, Args&&... args)
+    {
+        Ret resp;
+        try
+        {
+            sdbusplus::message::message respMsg = callMethod<Args...>(
+                busName, path, interface, method, std::forward<Args>(args)...);
+            respMsg.read(resp);
+        }
+        catch (const sdbusplus::exception::SdBusError&)
+        {
+        }
+        return resp;
+    }
+
+    using Path = std::string;
+    using Interface = std::string;
+    using Service = std::string;
+    using Interfaces = std::vector<Interface>;
+    using Services = std::map<Service, Interfaces>;
+    using Objects = std::map<Path, Services>;
+
+    /** @brief Get subtree from the mapper. */
+    static Objects getSubTree(const std::string& path, const Interfaces& ifaces,
+                              int32_t depth = 0)
+    {
+        using namespace std::literals::string_literals;
+
+        return callMethodAndRead<Objects>(
+            OBJECT_MAPPER_IFACE, OBJECT_MAPPER_PATH, OBJECT_MAPPER_IFACE,
+            "GetSubTree", path, depth, ifaces);
+    }
+
+    /** @brief Get subtree paths from mapper. */
+    static Interfaces getSubTreePaths(const std::string& path,
+                                      const Interfaces& ifaces,
+                                      int32_t depth = 0)
+    {
+        return callMethodAndRead<Interfaces>(
+            OBJECT_MAPPER_IFACE, OBJECT_MAPPER_PATH, OBJECT_MAPPER_IFACE,
+            "GetSubTreePaths", path, depth, ifaces);
+    }
+
+    /** @brief Get service provides specified object */
+    static Service getService(const Path& path, const Interface& iface)
+    {
+        Interfaces ifaces = {iface};
+        auto services = callMethodAndRead<Services>(
+            OBJECT_MAPPER_IFACE, OBJECT_MAPPER_PATH, OBJECT_MAPPER_IFACE,
+            "GetObject", path, ifaces);
+
+        if (!services.empty())
+        {
+            return std::move(services.begin()->first);
+        }
+
+        return {};
+    }
+
+    /** @brief Get a property. */
+    template <typename Property>
+    static Property
+        getProperty(const std::string& busName, const std::string& path,
+                    const std::string& interface, const std::string& property)
+    {
+        auto reqMsg = callMethod(busName, path, PROPERTIES_IFACE, "Get",
+                                 interface, property);
+        std::variant<Property> value;
+        reqMsg.read(value);
+        return value.template get<Property>();
+    }
+
+    /** @brief Get all properties. */
+    template <typename... Types>
+    static auto getAllProperties(const std::string& busName,
+                                 const std::string& path,
+                                 const std::string& interface)
+    {
+        using Value = std::variant<Types...>;
+        using Values = std::map<std::string, Value>;
+
+        auto reqMsg =
+            callMethod(busName, path, PROPERTIES_IFACE, "GetAll", interface);
+
+        Values values;
+        reqMsg.read(values);
+        return values;
+    }
+};
+
+} // namespace helper
+
+namespace bus
+{
+namespace match
+{
+namespace rules
+{
+inline auto propertiesChanged(const std::string& p)
+{
+    return type::signal() + path(p) + member("PropertiesChanged") +
+           interface(sdbusplus::helper::PROPERTIES_IFACE);
+}
+} // namespace rules
+} // namespace match
+} // namespace bus
+} // namespace sdbusplus
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