MXS-2196: Use smart pointers for lifetime management

The listeners no longer internally track whether they are active or
not. All of the heavy lifting is now done by std::shared_ptr.

include/maxscale/listener.hh

@@ -63,6 +63,16 @@ public:
                             const std::string& auth_options,
                             SSL_LISTENER* ssl);
 
+    /**
+     * Destroy a listener
+     *
+     * This removes the listener from the global list of active listeners. Once destroyed, the port used
+     * by a listener is open for immediate reuse.
+     *
+     * @param listener Listener to destroy
+     */
+    static void destroy(const SListener& listener);
+
     /**
      * Start listening on the configured port
      *
@@ -84,14 +94,6 @@ public:
      */
     bool start();
 
-    /**
-     * Closes a listener
-     *
-     * This closes the network socket the listener listens on to allow immediate reuse of it. The listener
-     * instance can remain if there are open sessions for it.
-     */
-    void close();
-
     /**
      * Listener name
      */
@@ -132,18 +134,6 @@ public:
      */
     const char* state() const;
 
-    /**
-     * Whether the listener is active
-     */
-    bool is_active() const;
-
-    /**
-     * Deactivate the listener
-     *
-     * TODO: Remove and deactivate via removal from global listener list
-     */
-    void deactivate();
-
     /**
      * The SSL_LISTENER object
      */
@@ -221,15 +211,6 @@ private:
  */
 bool listener_serialize(const SListener& listener);
 
-/**
- * @brief Free a listener
- *
- * The listener must be destroyed before it can be freed.
- *
- * @param listener Listener to free
- */
-void listener_free(const SListener& listener);
-
 /**
  * Find a listener
  *

server/core/listener.cc

@@ -57,7 +57,6 @@ Listener::Listener(SERVICE* service, const std::string& name, const std::string&
     , m_listener(nullptr)
     , m_users(nullptr)
     , m_service(service)
-    , m_active(1)
 {
 }
 
@@ -116,21 +115,17 @@ SListener Listener::create(SERVICE* service,
     return listener;
 }
 
-void listener_free(const SListener& listener)
+void Listener::destroy(const SListener& listener)
 {
-    std::lock_guard<std::mutex> guard(listener_lock);
-    all_listeners.remove(listener);
-}
-
-void Listener::close()
-{
-    deactivate();
-    stop();
+    listener->stop();
 
     // TODO: This is not pretty but it works, revise when listeners are refactored. This is
     // thread-safe as the listener is freed on the same thread that closes the socket.
-    ::close(m_listener->fd);
-    m_listener->fd = -1;
+    ::close(listener->m_listener->fd);
+    listener->m_listener->fd = -1;
+
+    std::lock_guard<std::mutex> guard(listener_lock);
+    all_listeners.remove(listener);
 }
 
 bool Listener::stop()
@@ -170,7 +165,7 @@ SListener listener_find(const std::string& name)
 
     for (const auto& a : all_listeners)
     {
-        if (a->is_active() && a->name() == name)
+        if (a->name() == name)
         {
             rval = a;
             break;
@@ -187,7 +182,7 @@ std::vector<SListener> listener_find_by_service(const SERVICE* service)
 
     for (const auto& a : all_listeners)
     {
-        if (a->is_active() && a->service() == service)
+        if (a->service() == service)
         {
             rval.push_back(a);
         }
@@ -616,16 +611,6 @@ json_t* Listener::to_json() const
     return rval;
 }
 
-void Listener::deactivate()
-{
-    m_active = false;
-}
-
-bool Listener::is_active() const
-{
-    return m_active;
-}
-
 const char* Listener::name() const
 {
     return m_name.c_str();

server/core/service.cc

@@ -236,12 +236,6 @@ Service::~Service()
 {
     mxs_rworker_delete_data(m_wkey);
 
-    for (const auto& tmp : listener_find_by_service(this))
-    {
-        mxb_assert(!tmp->is_active() || maxscale_teardown_in_progress());
-        listener_free(listener_find(tmp->name()));
-    }
-
     if (router && router_instance && router->destroyInstance)
     {
         router->destroyInstance(router_instance);
@@ -538,7 +532,7 @@ bool service_remove_listener(Service* service, const char* target)
 
     if (listener && listener->service() == service)
     {
-        listener->close();
+        Listener::destroy(listener);
         rval = true;
     }