sensorhandler: use entity-map from json if filled

Step 4 of the transition from YAML to JSON will return the data from the
JSON file if present and valid, otherwise it'll fallback and return the
default example YAML present in the repository.

Tested: This was not tested.
Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: I33c773fc53660a9eb5e27a8c8c3e231c64fe079d

1 files changed, 28 insertions, 2 deletions

diff --git a/entity_map_json.cpp b/entity_map_json.cpp
index 96ef61c..c0b836c 100644
--- a/entity_map_json.cpp
+++ b/entity_map_json.cpp
@@ -3,6 +3,7 @@
 #include <exception>
 #include <fstream>
 #include <ipmid/types.hpp>
+#include <memory>
 #include <nlohmann/json.hpp>
 #include <string>
 #include <utility>
@@ -14,9 +15,34 @@ namespace sensor
 
 extern const EntityInfoMap entities;
 
-const EntityInfoMap& getIpmiEntityRecords()
+EntityInfoMapContainer* EntityInfoMapContainer::getContainer()
 {
-    return entities;
+    static std::unique_ptr<EntityInfoMapContainer> instance;
+
+    if (!instance)
+    {
+        /* TODO: With multi-threading this would all need to be locked so
+         * the first thread to hit it would set it up.
+         */
+        EntityInfoMap builtEntityMap = buildEntityMapFromFile();
+        if (!builtEntityMap.empty())
+        {
+            instance = std::unique_ptr<EntityInfoMapContainer>(
+                new EntityInfoMapContainer(builtEntityMap));
+        }
+        else
+        {
+            instance = std::unique_ptr<EntityInfoMapContainer>(
+                new EntityInfoMapContainer(entities));
+        }
+    }
+
+    return instance.get();
+}
+
+const EntityInfoMap& EntityInfoMapContainer::getIpmiEntityRecords()
+{
+    return entityRecords;
 }
 
 EntityInfoMap buildEntityMapFromFile()