Move single FAB API under the separate class

SingleFab class provides functionalities to support single FAB feature.
This commit moves the single FAB related API under SingleFab class.

Change-Id: I8d55cd2134f5812f83f5fc5033df097ab1b1f8f2
Signed-off-by: Anupama B R <anupama.b.r1@ibm.com>
diff --git a/vpd-manager/include/constants.hpp b/vpd-manager/include/constants.hpp
index cddc8ab..f71b18e 100644
--- a/vpd-manager/include/constants.hpp
+++ b/vpd-manager/include/constants.hpp
@@ -121,8 +121,6 @@
 constexpr auto systemInvPath = "/xyz/openbmc_project/inventory/system";
 constexpr auto pimPath = "/xyz/openbmc_project/inventory";
 constexpr auto pimIntf = "xyz.openbmc_project.Inventory.Manager";
-constexpr auto pimPersistVsbpPath =
-    "/var/lib/phosphor-inventory-manager/xyz/openbmc_project/inventory/system/chassis/motherboard/com.ibm.ipzvpd.VSBP";
 constexpr auto ipzVpdInf = "com.ibm.ipzvpd.";
 constexpr auto kwdVpdInf = "com.ibm.ipzvpd.VINI";
 constexpr auto vsysInf = "com.ibm.ipzvpd.VSYS";
diff --git a/vpd-manager/include/single_fab.hpp b/vpd-manager/include/single_fab.hpp
new file mode 100644
index 0000000..03c6cee
--- /dev/null
+++ b/vpd-manager/include/single_fab.hpp
@@ -0,0 +1,26 @@
+#pragma once
+
+#include <string>
+
+namespace vpd
+{
+/**
+ * @brief class to implement single fab feature.
+ *
+ * The class hosts functionalities required to support single FAB feature.
+ *
+ */
+class SingleFab
+{
+    // ToDo: public API to be implemented, which can be called by the user to
+    // support single FAB.
+
+  private:
+    /**
+     * @brief API to get IM value from persisted location.
+     *
+     * @return IM value on success, empty string otherwise.
+     */
+    std::string getImFromPersistedLocation() const noexcept;
+};
+} // namespace vpd
diff --git a/vpd-manager/include/utility/json_utility.hpp b/vpd-manager/include/utility/json_utility.hpp
index 9ecdf74..c3d358c 100644
--- a/vpd-manager/include/utility/json_utility.hpp
+++ b/vpd-manager/include/utility/json_utility.hpp
@@ -1113,46 +1113,5 @@
         return nlohmann::json{};
     }
 }
-
-/** @brief API to get IM value from persisted data location.
- *
- * @return IM value on success, empty string otherwise.
- */
-inline std::string getImFromPersistedLocation() noexcept
-{
-    std::string l_imFilePath{constants::pimPersistVsbpPath};
-
-    try
-    {
-        auto l_parsedVsbpJsonObj = getParsedJson(l_imFilePath);
-        if (!l_parsedVsbpJsonObj.contains("value0") ||
-            !l_parsedVsbpJsonObj["value0"].contains(constants::kwdIM) ||
-            !l_parsedVsbpJsonObj["value0"][constants::kwdIM].is_array())
-        {
-            throw std::runtime_error(
-                "Json is empty or mandatory tag(s) missing from JSON");
-        }
-
-        types::BinaryVector l_imValue =
-            l_parsedVsbpJsonObj["value0"][constants::kwdIM]
-                .get<types::BinaryVector>();
-
-        std::ostringstream l_imData;
-        for (auto& l_byte : l_imValue)
-        {
-            l_imData << std::setw(2) << std::setfill('0') << std::hex
-                     << static_cast<int>(l_byte);
-        }
-        return l_imData.str();
-    }
-    catch (const std::exception& l_ex)
-    {
-        logging::logMessage(
-            "Error while getting IM value from PIM persisted file: " +
-            l_imFilePath + ", reason: " + std::string(l_ex.what()));
-    }
-
-    return std::string();
-}
 } // namespace jsonUtility
 } // namespace vpd