MXS-2178 Reduce accessbility of workarounds

Some rearrangements to ensure that what should be private
can be kept private.

- WatchdogNotifier made a friend.
- WatchdogWorkaround defined in RoutingWorker and made a friend.
- mxs::WatchdogWorker defined with 'using'.

include/maxscale/routingworker.hh

@@ -433,69 +433,10 @@ public:
      */
     static void set_watchdog_interval(uint64_t microseconds);
 
-    /**
+    class WatchdogWorkaround;
-     * The internal watchdog interval.
+    friend WatchdogWorkaround;
-     *
-     * @return The interval in seconds, 0 if not enabled.
-     */
-    static uint32_t get_internal_watchdog_interval()
-    {
-        return s_watchdog_interval.secs();
-    }
-
-    // TODO: Public now ONLY so that it can be used in the workaround for the
-    // TODO "long max[admin|ctrl] operations may trigger the watchdog" problem.
-    void check_systemd_watchdog();
 
     /**
-     * Turn on the watchdog workaround for this worker.
-     *
-     * @see mxs::WatchdogWorkaround
-     */
-    void start_watchdog_workaround();
-
-    /**
-     * Turn off the watchdog workaround for this worker.
-     *
-     * @see mxs::WatchdogWorkaround
-     */
-    void stop_watchdog_workaround();
-
-private:
-    class WatchdogNotifier;
-
-    const int    m_id;              /*< The id of the worker. */
-    SessionsById m_sessions;        /*< A mapping of session_id->MXS_SESSION. The map
-                                     *  should contain sessions exclusive to this
-                                     *  worker and not e.g. listener sessions. For now,
-                                     *  it's up to the protocol to decide whether a new
-                                     *  session is added to the map. */
-    Zombies      m_zombies;         /*< DCBs to be deleted. */
-    LocalData    m_local_data;      /*< Data local to this worker */
-    DataDeleters m_data_deleters;   /*< Delete functions for the local data */
-
-    RoutingWorker();
-    virtual ~RoutingWorker();
-
-    static RoutingWorker* create(int epoll_listener_fd);
-
-    bool pre_run();     // override
-    void post_run();    // override
-    void epoll_tick();  // override
-
-    void delete_zombies();
-    //void check_systemd_watchdog();
-
-    static uint32_t epoll_instance_handler(MXB_POLL_DATA* data, MXB_WORKER* worker, uint32_t events);
-    uint32_t        handle_epoll_events(uint32_t events);
-
-    static maxbase::Duration  s_watchdog_interval;    /*< Duration between notifications, if any. */
-    static maxbase::TimePoint s_watchdog_next_check;  /*< Next time to notify systemd. */
-    std::atomic<bool>         m_alive;                /*< Set to true in epoll_tick(), false on notification. */
-    WatchdogNotifier*         m_pWatchdog_notifier;   /*< Watchdog notifier, if systemd enabled. */
-};
-
-/**
      * @class WatchdogWorkaround
      *
      * RAII-class using which the systemd watchdog notification can be
@@ -505,12 +446,12 @@ private:
      * The constructor turns on the workaround and the destructor
      * turns it off.
      */
-class WatchdogWorkaround
+    class WatchdogWorkaround
-{
+    {
         WatchdogWorkaround(const WatchdogWorkaround&);
         WatchdogWorkaround& operator=(const WatchdogWorkaround&);
 
-public:
+    public:
         /**
          * Turns on the watchdog workaround for a specific worker.
          *
@@ -540,10 +481,49 @@ public:
             m_pWorker->stop_watchdog_workaround();
         }
 
-private:
+    private:
         RoutingWorker* m_pWorker;
+    };
+
+private:
+    class WatchdogNotifier;
+    friend WatchdogNotifier;
+
+    const int    m_id;              /*< The id of the worker. */
+    SessionsById m_sessions;        /*< A mapping of session_id->MXS_SESSION. The map
+                                     *  should contain sessions exclusive to this
+                                     *  worker and not e.g. listener sessions. For now,
+                                     *  it's up to the protocol to decide whether a new
+                                     *  session is added to the map. */
+    Zombies      m_zombies;         /*< DCBs to be deleted. */
+    LocalData    m_local_data;      /*< Data local to this worker */
+    DataDeleters m_data_deleters;   /*< Delete functions for the local data */
+
+    RoutingWorker();
+    virtual ~RoutingWorker();
+
+    static RoutingWorker* create(int epoll_listener_fd);
+
+    bool pre_run();     // override
+    void post_run();    // override
+    void epoll_tick();  // override
+
+    void delete_zombies();
+    void check_systemd_watchdog();
+    void start_watchdog_workaround();
+    void stop_watchdog_workaround();
+
+    static uint32_t epoll_instance_handler(MXB_POLL_DATA* data, MXB_WORKER* worker, uint32_t events);
+    uint32_t        handle_epoll_events(uint32_t events);
+
+    static maxbase::Duration  s_watchdog_interval;    /*< Duration between notifications, if any. */
+    static maxbase::TimePoint s_watchdog_next_check;  /*< Next time to notify systemd. */
+    std::atomic<bool>         m_alive;                /*< Set to true in epoll_tick(), false on notification. */
+    WatchdogNotifier*         m_pWatchdog_notifier;   /*< Watchdog notifier, if systemd enabled. */
 };
 
+using WatchdogWorkaround = RoutingWorker::WatchdogWorkaround;
+
 // Data local to a routing worker
 template<class T>
 class rworker_local

server/core/routingworker.cc

@@ -183,7 +183,7 @@ public:
         , m_terminate(false)
     {
         m_thread = std::thread([this] {
-                uint32_t interval = mxs::RoutingWorker::get_internal_watchdog_interval();
+                uint32_t interval = mxs::RoutingWorker::s_watchdog_interval.secs();
                 timespec timeout = { interval, 0 };
 
                 while (!mxb::atomic::load(&m_terminate, mxb::atomic::RELAXED))