[Server] Expose the latest uptime snapshot on the database interface (#7840)

cmdGetServerStats reached through Servatrice_DatabaseInterface for checkSql and
getLatestUptimeSnapshot, a concrete-only method. Move the UptimeSnapshot record
to Server_DatabaseInterface with an invalid default for non-SQL stores, mark the
Servatrice implementation as an override, and let the command ask the injected
interface. The statement, its bind value and the invalid-snapshot response are
unchanged.

libcockatrice_network/libcockatrice/network/server/remote/server_database_interface.h

@@ -425,6 +425,24 @@ public:
     virtual int getNextReplayId() = 0;
     virtual int getActiveUserCount(QString connectionType = QString()) = 0;
 
+    /** @brief Snapshot recorded by the server's periodic status update into the uptime table. */
+    struct UptimeSnapshot
+    {
+        bool valid = false;
+        quint64 usersCount = 0;
+        quint64 modsCount = 0;
+        quint64 gamesCount = 0;
+        quint64 txBytes = 0;
+        quint64 rxBytes = 0;
+        quint64 uptimeSecs = 0;
+        quint64 timest = 0;
+    };
+    /** @brief Freshest uptime snapshot of one server; an invalid snapshot when none exists. */
+    virtual UptimeSnapshot getLatestUptimeSnapshot(int /* serverId */)
+    {
+        return {};
+    }
+
     virtual void clearSessionTables()
     {
     }

servatrice/src/servatrice_database_interface.cpp

@@ -3008,7 +3008,7 @@ QList<ServerInfo_ModeratorLogin> Servatrice_DatabaseInterface::getModeratorLastL
     return results;
 }
 
-Servatrice_DatabaseInterface::UptimeSnapshot Servatrice_DatabaseInterface::getLatestUptimeSnapshot(int serverId)
+Server_DatabaseInterface::UptimeSnapshot Servatrice_DatabaseInterface::getLatestUptimeSnapshot(int serverId)
 {
     UptimeSnapshot snapshot;
 

servatrice/src/servatrice_database_interface.h

@@ -257,18 +257,7 @@ public:
 
     // Uptime snapshot as recorded by Servatrice::statusUpdate() into the
     // {prefix}_uptime table. valid is false when no snapshot exists yet.
-    struct UptimeSnapshot
+    UptimeSnapshot getLatestUptimeSnapshot(int serverId) override;
-    {
-        bool valid = false;
-        quint64 usersCount = 0;
-        quint64 modsCount = 0;
-        quint64 gamesCount = 0;
-        quint64 txBytes = 0;
-        quint64 rxBytes = 0;
-        quint64 uptimeSecs = 0;
-        quint64 timest = 0;
-    };
-    UptimeSnapshot getLatestUptimeSnapshot(int serverId);
     bool removeUserAvatar(const QString &userName);
 
     // Outcome of removeUserBanner(), so the caller can tell a missing user apart

servatrice/src/serversocketinterface.cpp

@@ -2186,13 +2186,13 @@ Response::ResponseCode AbstractServerSocketInterface::cmdReportUserInfo(const Co
 Response::ResponseCode AbstractServerSocketInterface::cmdGetServerStats(const Command_GetServerStats & /*cmd */,
                                                                         ResponseContainer &rc)
 {
-    if (!sqlInterface->checkSql()) {
+    if (!databaseInterface->checkSql()) {
         return Response::RespInternalError;
     }
 
     // Servatrice::statusUpdate() periodically snapshots server health into the
     // uptime table. Serve the freshest snapshot for this server.
-    const auto snapshot = sqlInterface->getLatestUptimeSnapshot(servatrice->getServerID());
+    const auto snapshot = databaseInterface->getLatestUptimeSnapshot(servatrice->getServerID());
     if (!snapshot.valid) {
         // No snapshot yet (fresh server, or statusUpdate() has not ticked).
         return Response::RespInternalError;