Add support of std::stream for logger

Logger can be used as a std::ostream.

// Console logger with color
auto console = spd::stdout_color_mt("console");
console->info() << "Welcome to spdlog!";
console->error() << "Some error message with arg" << 1 << "..";

include/spdlog/details/logger_impl.h

@@ -197,8 +197,42 @@ inline void spdlog::logger::critical(const T& msg)
     log(level::critical, msg);
 }
 
+inline spdlog::ostream spdlog::logger::log(level::level_enum lvl)
+{
+    if (!should_log(lvl))
+
+    return ostream(this, lvl);
+}
+
+inline spdlog::ostream spdlog::logger::trace()
+{
+   return log(level::trace);
+}
 
+inline spdlog::ostream spdlog::logger::debug()
+{
+   return log(level::debug);
+}
 
+inline spdlog::ostream spdlog::logger::info()
+{
+   return log(level::info);
+}
+
+inline spdlog::ostream spdlog::logger::warn()
+{
+   return log(level::warn);
+}
+
+inline spdlog::ostream spdlog::logger::error()
+{
+   return log(level::err);
+}
+
+inline spdlog::ostream spdlog::logger::critical()
+{
+   return log(level::critical);
+}
 
 //
 // name and level

include/spdlog/details/stream_impl.h

@@ -0,0 +1,29 @@
+//
+// Copyright(c) 2017 Benoit Leforestier.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+template <class CharT, class Traits>
+spdlog::basic_streambuf<CharT, Traits>::basic_streambuf(spdlog::logger* plogger, spdlog::level::level_enum lvl) :
+{
+}
+
+template <class CharT, class Traits>
+spdlog::basic_streambuf<CharT, Traits>::basic_streambuf(basic_streambuf&& rhs) :
+{
+}
+
+template <class CharT, class Traits>
+spdlog::basic_streambuf<CharT, Traits>::~basic_streambuf()
+{
+
+}
+
+template <class CharT, class Traits>
+std::streamsize spdlog::basic_streambuf<CharT, Traits>::xsputn(const char_type* __s, std::streamsize __n)
+{
+
+
+}

include/spdlog/logger.h

@@ -14,6 +14,7 @@
 
 #include <spdlog/sinks/base_sink.h>
 #include <spdlog/common.h>
+#include <spdlog/stream.h>
 
 #include <vector>
 #include <memory>
@@ -52,6 +53,14 @@ public:
     template <typename T> void error(const T&);
     template <typename T> void critical(const T&);
 
+    ostream log(level::level_enum lvl);
+    ostream trace();
+    ostream debug();
+    ostream info();
+    ostream warn();
+    ostream error();
+    ostream critical();
+
     bool should_log(level::level_enum) const;
     void set_level(level::level_enum);
     level::level_enum level() const;
@@ -71,6 +80,9 @@ public:
     const std::vector<sink_ptr>& sinks() const;
 
 protected:
+    template <class CharT, class Traits>
+    friend class basic_streambuf;
+
     virtual void _sink_it(details::log_msg&);
     virtual void _set_pattern(const std::string&);
     virtual void _set_formatter(formatter_ptr);
@@ -92,3 +104,4 @@ protected:
 }
 
 #include <spdlog/details/logger_impl.h>
+#include <spdlog/details/stream_impl.h>

include/spdlog/stream.h

@@ -0,0 +1,26 @@
+//
+// Copyright(c) 2017 Benoit Leforestier.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+#include <ostream>
+
+namespace spdlog
+{
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+}