Make sure that the logger static lock mutex is not destroyed before a…

…ny global client instance (#977) (#991)

* Changed the logger lock mutex so that we can control its destruction order properly. We do not want it destroyed before the client is destructed. We need to control the order. static initialization and destruction order is not controllable if it is not a member of the logger class. It can be destroyed before the any global client istance is destroyed since global variables are also in static duration (https://www.learncpp.com/cpp-tutorial/introduction-to-global-variables).

hazelcast/include/hazelcast/logger.h

@@ -3,6 +3,7 @@
 #include <string>
 #include <functional>
 #include <limits>
+#include <mutex>
 
 #include "hazelcast/util/export.h"
 
@@ -52,6 +53,7 @@ class HAZELCAST_API logger {
     const std::string cluster_name_;
     const level level_;
     const handler_type handler_;
+    static std::mutex cout_lock_;
 };
 
 enum class logger::level : int {

hazelcast/src/hazelcast/logger.cpp

@@ -1,6 +1,5 @@
 #include <iomanip>
 #include <iostream>
-#include <mutex>
 #include <sstream>
 #include <chrono>
 #include <ctime>
@@ -42,7 +41,7 @@ logger::logger(std::string instance_name, std::string cluster_name, level level,
     : instance_name_{ std::move(instance_name) }
     , cluster_name_{ std::move(cluster_name) }
     , level_{ level }
-    , handler_{ std::move(handler) } 
+    , handler_{ std::move(handler) }
 {}
 
 bool logger::enabled(level lvl) noexcept {
@@ -69,18 +68,22 @@ std::tm time_t_to_localtime(const std::time_t &t) {
 
 }
 
-void logger::default_handler(const std::string &instance_name,
-                             const std::string &cluster_name,
-                             level lvl, 
-                             const std::string &msg) noexcept {
+std::mutex logger::cout_lock_;
+
+void
+logger::default_handler(const std::string& instance_name,
+                        const std::string& cluster_name,
+                        level lvl,
+                        const std::string& msg) noexcept
+{
 
     auto tp = std::chrono::system_clock::now();
     auto t = std::chrono::system_clock::to_time_t(tp);
     auto local_t = time_t_to_localtime(t);
 
     auto dur = tp.time_since_epoch();
     auto sec = std::chrono::duration_cast<std::chrono::seconds>(dur);
-    
+
     auto ms = std::chrono::duration_cast<std::chrono::milliseconds>(dur - sec).count();
 
     std::ostringstream sstrm;
@@ -96,11 +99,10 @@ void logger::default_handler(const std::string &instance_name,
           << '\n';
 
     {
-        static std::mutex cout_lock;
-        std::lock_guard<std::mutex> g(cout_lock);
+        std::lock_guard<std::mutex> g(cout_lock_);
         std::cout << sstrm.str() << std::flush;
     }
-} 
+}
 
 
 } // namespace hazelcast