Don't use color escape codes if terminal doesn't support them in ansicolor_sink

include/spdlog/details/os.h

@@ -12,6 +12,7 @@
 #include <string>
 #include <chrono>
 #include <thread>
+#include <algorithm>
 #include <stdio.h>
 #include <string.h>
 #include <sys/stat.h>
@@ -401,6 +402,32 @@ inline int pid()
 
 }
 
+
+// Detrmine if the terminal supports colors
+// Source: https://github.com/agauniyal/rang/
+bool is_color_terminal()
+{
+#ifdef _WIN32
+	return true;
+#else		
+	static constexpr const char* Terms[] = {
+		"ansi", "color", "console", "cygwin", "gnome", "konsole", "kterm",
+		"linux", "msys", "putty", "rxvt", "screen", "vt100", "xterm"
+	};
+
+	const char *env_p = std::getenv("TERM");
+	if (env_p == nullptr) {
+		return false;
+	}
+
+	static const bool result = std::any_of(
+		std::begin(Terms), std::end(Terms), [&](const char* term) {
+		return std::strstr(env_p, term) != nullptr;
+	});
+#endif 
+}
+
+
 } //os
 } //details
 } //spdlog

include/spdlog/sinks/ansicolor_sink.h

@@ -7,110 +7,119 @@
 
 #include <spdlog/sinks/base_sink.h>
 #include <spdlog/common.h>
+#include <spdlog/details/os.h>
 
 #include <string>
 #include <map>
 
 namespace spdlog
 {
-namespace sinks
-{
-
-/**
- * @brief The ansi_color_sink is a decorator around another sink and prefixes
- * the output with an ANSI escape sequence color code depending on the severity
- * of the message.
- */
-class ansicolor_sink SPDLOG_FINAL : public sink
-{
-public:
-    ansicolor_sink(sink_ptr wrapped_sink);
-    virtual ~ansicolor_sink();
-
-    ansicolor_sink(const ansicolor_sink& other) = delete;
-    ansicolor_sink& operator=(const ansicolor_sink& other) = delete;
-
-    virtual void log(const details::log_msg& msg) override;
-    virtual void flush() override;
-
-    void set_color(level::level_enum color_level, const std::string& color);
-
-    /// Formatting codes
-    const std::string reset      = "\033[00m";
-    const std::string bold       = "\033[1m";
-    const std::string dark       = "\033[2m";
-    const std::string underline  = "\033[4m";
-    const std::string blink      = "\033[5m";
-    const std::string reverse    = "\033[7m";
-    const std::string concealed  = "\033[8m";
-
-    // Foreground colors
-    const std::string grey       = "\033[30m";
-    const std::string red        = "\033[31m";
-    const std::string green      = "\033[32m";
-    const std::string yellow     = "\033[33m";
-    const std::string blue       = "\033[34m";
-    const std::string magenta    = "\033[35m";
-    const std::string cyan       = "\033[36m";
-    const std::string white      = "\033[37m";
-
-    /// Background colors
-    const std::string on_grey    = "\033[40m";
-    const std::string on_red     = "\033[41m";
-    const std::string on_green   = "\033[42m";
-    const std::string on_yellow  = "\033[43m";
-    const std::string on_blue    = "\033[44m";
-    const std::string on_magenta = "\033[45m";
-    const std::string on_cyan    = "\033[46m";
-    const std::string on_white   = "\033[47m";
-
-
-protected:
-    sink_ptr sink_;
-    std::map<level::level_enum, std::string> colors_;
-};
-
-inline ansicolor_sink::ansicolor_sink(sink_ptr wrapped_sink) : sink_(wrapped_sink)
-{
-    colors_[level::trace]   = cyan;
-    colors_[level::debug]   = cyan;
-    colors_[level::info]    = bold;
-    colors_[level::warn]    = yellow + bold;
-    colors_[level::err]     = red + bold;
-    colors_[level::critical] = bold + on_red;
-    colors_[level::off]      = reset;
-}
-
-inline void ansicolor_sink::log(const details::log_msg& msg)
-{
-    // Wrap the originally formatted message in color codes
-    const std::string& prefix = colors_[msg.level];
-    const std::string& s = msg.formatted.str();
-    const std::string& suffix = reset;
-    details::log_msg m;
-    m.level = msg.level;
-    m.logger_name = msg.logger_name;
-    m.time = msg.time;
-    m.thread_id = msg.thread_id;
-    m.formatted << prefix  << s << suffix;
-    sink_->log(m);
-}
-
-inline void ansicolor_sink::flush()
-{
-    sink_->flush();
-}
-
-inline void ansicolor_sink::set_color(level::level_enum color_level, const std::string& color)
-{
-    colors_[color_level] = color;
-}
-
-inline ansicolor_sink::~ansicolor_sink()
-{
-    flush();
-}
-
-} // namespace sinks
+	namespace sinks
+	{
+
+		/**
+		 * @brief The ansi_color_sink is a decorator around another sink and prefixes
+		 * the output with an ANSI escape sequence color code depending on the severity
+		 * of the message.
+		 */
+		class ansicolor_sink SPDLOG_FINAL: public sink
+		{
+		public:
+			ansicolor_sink(sink_ptr wrapped_sink);
+			virtual ~ansicolor_sink();
+
+			ansicolor_sink(const ansicolor_sink& other) = delete;
+			ansicolor_sink& operator=(const ansicolor_sink& other) = delete;
+
+			virtual void log(const details::log_msg& msg) override;
+			virtual void flush() override;
+
+			void set_color(level::level_enum color_level, const std::string& color);
+
+			/// Formatting codes
+			const std::string reset = "\033[00m";
+			const std::string bold = "\033[1m";
+			const std::string dark = "\033[2m";
+			const std::string underline = "\033[4m";
+			const std::string blink = "\033[5m";
+			const std::string reverse = "\033[7m";
+			const std::string concealed = "\033[8m";
+
+			// Foreground colors
+			const std::string grey = "\033[30m";
+			const std::string red = "\033[31m";
+			const std::string green = "\033[32m";
+			const std::string yellow = "\033[33m";
+			const std::string blue = "\033[34m";
+			const std::string magenta = "\033[35m";
+			const std::string cyan = "\033[36m";
+			const std::string white = "\033[37m";
+
+			/// Background colors
+			const std::string on_grey = "\033[40m";
+			const std::string on_red = "\033[41m";
+			const std::string on_green = "\033[42m";
+			const std::string on_yellow = "\033[43m";
+			const std::string on_blue = "\033[44m";
+			const std::string on_magenta = "\033[45m";
+			const std::string on_cyan = "\033[46m";
+			const std::string on_white = "\033[47m";
+
+
+		protected:
+			bool is_color_terminal_;
+			sink_ptr sink_;
+			std::map<level::level_enum, std::string> colors_;
+		};
+
+		inline ansicolor_sink::ansicolor_sink(sink_ptr wrapped_sink): sink_(wrapped_sink)
+		{
+			is_color_terminal_ = details::os::is_color_terminal();
+			colors_[level::trace] = cyan;
+			colors_[level::debug] = cyan;
+			colors_[level::info] = bold;
+			colors_[level::warn] = yellow + bold;
+			colors_[level::err] = red + bold;
+			colors_[level::critical] = bold + on_red;
+			colors_[level::off] = reset;
+		}
+
+		inline void ansicolor_sink::log(const details::log_msg& msg)
+		{
+			// Wrap the originally formatted message in color codes.
+			// If color is not supported in the terminal, log as is instead.
+			if (is_color_terminal_) {
+				const std::string& prefix = colors_[msg.level];
+				const std::string& s = msg.formatted.str();
+				const std::string& suffix = reset;
+				details::log_msg m;
+				m.level = msg.level;
+				m.logger_name = msg.logger_name;
+				m.time = msg.time;
+				m.thread_id = msg.thread_id;
+				m.formatted << prefix << s << suffix;
+				sink_->log(m);
+			}
+			else {
+				sink_->log(msg);
+			}
+		}
+
+		inline void ansicolor_sink::flush()
+		{
+			sink_->flush();
+		}
+
+		inline void ansicolor_sink::set_color(level::level_enum color_level, const std::string& color)
+		{
+			colors_[color_level] = color;
+		}
+
+		inline ansicolor_sink::~ansicolor_sink()
+		{
+			flush();
+		}
+
+	} // namespace sinks
 } // namespace spdlog