Simplify fillMessageArgs

The aforementioned function does a lot of reconstruction of strings as
args are filled in.  This results in the end of the string being copied
many times (N).  Replace the algorithm with one that builds a new
string, using reserve (which is good practice) and is also capable of
returning errors in the case of bad entries.  fillMessageArgs now
returns a string instead of trying to do things in place, which avoids
the initial std::string construction, so we should be net the same here.

Given this new algorithm can now detect failures in parsing (ie, trying
to parse %1 with no arguments) add unit tests for coverage of that, and
modify event manager slightly to handle errors.

Tested: Unit tests pass.  Pretty good coverage of this stuff.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: I16f28a2ac78580fb35266561f5ae38078b471989

1 files changed, 9 insertions, 7 deletions

diff --git a/redfish-core/include/event_service_manager.hpp b/redfish-core/include/event_service_manager.hpp
index 6b3f84fc90..d581aeb283 100644
--- a/redfish-core/include/event_service_manager.hpp
+++ b/redfish-core/include/event_service_manager.hpp
@@ -235,15 +235,17 @@ inline int formatEventLogEntry(const std::string& logEntryID,
     // Get the Message from the MessageRegistry
     const registries::Message* message = registries::formatMessage(messageID);
 
-    std::string msg;
-    std::string severity;
-    if (message != nullptr)
+    if (message == nullptr)
     {
-        msg = message->message;
-        severity = message->messageSeverity;
+        return -1;
     }
 
-    redfish::registries::fillMessageArgs(messageArgs, msg);
+    std::string msg =
+        redfish::registries::fillMessageArgs(messageArgs, message->message);
+    if (msg.empty())
+    {
+        return -1;
+    }
 
     // Get the Created time from the timestamp. The log timestamp is in
     // RFC3339 format which matches the Redfish format except for the
@@ -258,7 +260,7 @@ inline int formatEventLogEntry(const std::string& logEntryID,
     // Fill in the log entry with the gathered data
     logEntryJson["EventId"] = logEntryID;
     logEntryJson["EventType"] = "Event";
-    logEntryJson["Severity"] = std::move(severity);
+    logEntryJson["Severity"] = message->messageSeverity;
     logEntryJson["Message"] = std::move(msg);
     logEntryJson["MessageId"] = messageID;
     logEntryJson["MessageArgs"] = messageArgs;