Added async_nonblocking factory

include/spdlog/async.h

@@ -21,9 +21,11 @@
 #include <memory>
 namespace spdlog {
 
+
 // async logger factory - creates async loggers backed with thread pool.
 // if a global thread pool doesn't already exist, create it with default queue size of 8192 items and single thread.
-struct async_factory
+template<async_overflow_policy OverflowPolicy = async_overflow_policy::block>
+struct async_factory_impl
 {
     template<typename Sink, typename... SinkArgs>
     static std::shared_ptr<async_logger> create(const std::string &logger_name, SinkArgs &&... args)
@@ -39,18 +41,29 @@ struct async_factory
         }
 
         auto sink = std::make_shared<Sink>(std::forward<SinkArgs>(args)...);
-        auto new_logger = std::make_shared<async_logger>(logger_name, std::move(sink), std::move(tp), async_overflow_policy::block);
+        auto new_logger = std::make_shared<async_logger>(logger_name, std::move(sink), std::move(tp), OverflowPolicy);
         registry::instance().register_and_init(new_logger);
         return new_logger;
     }
 };
 
+using async_factory = async_factory_impl<async_overflow_policy::block>;
+using async_factory_nonblock = async_factory_impl < async_overflow_policy::overrun_oldest>;
+
+
 template<typename Sink, typename... SinkArgs>
 inline std::shared_ptr<spdlog::logger> create_async(const std::string &logger_name, SinkArgs &&... sink_args)
 {
     return async_factory::create<Sink>(logger_name, std::forward<SinkArgs>(sink_args)...);
 }
 
+template<typename Sink, typename... SinkArgs>
+inline std::shared_ptr<spdlog::logger> create_async_nb(const std::string &logger_name, SinkArgs &&... sink_args)
+{
+    return async_factory<spdlog::async_overflow_policy::overrun_oldest>::create<Sink>(logger_name, std::forward<SinkArgs>(sink_args)...);
+}
+    
+
 // set global thread pool.
 inline void init_thread_pool(size_t q_size, size_t thread_count)
 {

include/spdlog/async_logger.h

@@ -23,6 +23,14 @@
 #include <string>
 
 namespace spdlog {
+
+// Async overflow policy - block by default.
+enum class async_overflow_policy
+{
+    block,         // Block until message can be enqueued
+    overrun_oldest // Discard oldest message in the queue if full when trying to add new item.
+};
+
 namespace details {
 class thread_pool;
 }

include/spdlog/common.h

@@ -121,14 +121,7 @@ inline spdlog::level::level_enum from_str(const std::string &name)
 using level_hasher = std::hash<int>;
 } // namespace level
 
-//
+
-// Async overflow policy - block by default.
-//
-enum class async_overflow_policy
-{
-    block,         // Block until message can be enqueued
-    overrun_oldest // Discard oldest message in the queue if full when trying to add new item.
-};
 
 //
 // Pattern time - specific time getting to use for pattern_formatter.