pattern per sink and pattern caching

include/spdlog/sinks/sink.h

@@ -6,39 +6,62 @@
 #pragma once
 
 #include "spdlog/details/log_msg.h"
+#include "spdlog/formatter.h"
 
 namespace spdlog {
 namespace sinks {
 class sink
 {
 public:
+    // default sink ctor with default pattern formatter
+    sink()
+        : formatter_(std::unique_ptr<spdlog::formatter>(new pattern_formatter("%+")))
+    {
+    }
+
+    explicit sink(const std::string &formatter_pattern)
+        : formatter_(std::unique_ptr<spdlog::formatter>(new pattern_formatter(formatter_pattern)))
+    {
+    }
+
+    // sink with custom formatter
+    explicit sink(std::unique_ptr<spdlog::formatter> sink_formatter)
+        : formatter_(std::move(sink_formatter))
+    {
+    }
+
     virtual ~sink() = default;
 
     virtual void log(const details::log_msg &msg) = 0;
     virtual void flush() = 0;
 
-    bool should_log(level::level_enum msg_level) const;
-    void set_level(level::level_enum log_level);
-    level::level_enum level() const;
+    bool should_log(level::level_enum msg_level) const
+    {
+        return msg_level >= level_.load(std::memory_order_relaxed);
+    }
+    void set_level(level::level_enum log_level)
+    {
+        level_.store(log_level);
+    }
+    level::level_enum level() const
+    {
+        return static_cast<spdlog::level::level_enum>(level_.load(std::memory_order_relaxed));
+    }
 
-private:
+    void set_formatter(std::unique_ptr<spdlog::formatter> sink_formatter)
+    {
+        formatter_ = std::move(sink_formatter);
+    }
+
+    spdlog::formatter *formatter()
+    {
+        return formatter_.get();
+    }
+
+protected:
     level_t level_{level::trace};
+    std::unique_ptr<spdlog::formatter> formatter_;
 };
 
-inline bool sink::should_log(level::level_enum msg_level) const
-{
-    return msg_level >= level_.load(std::memory_order_relaxed);
-}
-
-inline void sink::set_level(level::level_enum log_level)
-{
-    level_.store(log_level);
-}
-
-inline level::level_enum sink::level() const
-{
-    return static_cast<spdlog::level::level_enum>(level_.load(std::memory_order_relaxed));
-}
-
 } // namespace sinks
 } // namespace spdlog