add loglevel none (closing #998)

contrib/i2pd.conf

@@ -23,7 +23,8 @@
 # log = file
 ## Path to logfile (default - autodetect)
 # logfile = /var/log/i2pd.log
-## Log messages above this level (debug, *info, warn, error)
+## Log messages above this level (debug, *info, warn, error, none)
+## If you set it to none, logging will be disabled
 # loglevel = info
 
 ## Path to storage of i2pd data (RI, keys, peer profiles, ...)

libi2pd/Log.cpp

@@ -16,6 +16,7 @@ namespace log {
 	 */
 	static const char * g_LogLevelStr[eNumLogLevels] =
 	{
+		"none",  // eLogNone
 		"error", // eLogError
 		"warn",  // eLogWarn
 		"info",  // eLogInfo
@@ -46,6 +47,7 @@ namespace log {
 	static inline int GetSyslogPrio (enum LogLevel l) {
 		int priority = LOG_DEBUG;
 		switch (l) {
+			case eLogNone    : priority = LOG_CRIT;    break;
 			case eLogError   : priority = LOG_ERR;     break;
 			case eLogWarning : priority = LOG_WARNING; break;
 			case eLogInfo    : priority = LOG_INFO;    break;
@@ -105,7 +107,8 @@ namespace log {
 	}
 
 	void Log::SetLogLevel (const std::string& level) {
-		if      (level == "error") { m_MinLevel = eLogError; }
+		if      (level == "none")  { m_MinLevel = eLogNone; }
+		else if (level == "error") { m_MinLevel = eLogError; }
 		else if (level == "warn")  { m_MinLevel = eLogWarning; }
 		else if (level == "info")  { m_MinLevel = eLogInfo;  }
 		else if (level == "debug") { m_MinLevel = eLogDebug; }
@@ -181,6 +184,7 @@ namespace log {
 	void Log::SendTo (const std::string& path)
 	{
 		if (m_LogStream) m_LogStream = nullptr; // close previous
+		if (m_MinLevel == eLogNone) return;
 		auto flags = std::ofstream::out | std::ofstream::app;
 		auto os = std::make_shared<std::ofstream> (path, flags);
 		if (os->is_open ())
@@ -202,6 +206,7 @@ namespace log {
 
 #ifndef _WIN32
 	void Log::SendTo(const char *name, int facility) {
+		if (m_MinLevel == eLogNone) return;
 		m_HasColors = false;
 		m_Destination = eLogSyslog;
 		m_LogStream = nullptr;

libi2pd/Log.h

@@ -25,7 +25,8 @@
 
 enum LogLevel
 {
-	eLogError = 0,
+	eLogNone = 0,
+	eLogError,
 	eLogWarning,
 	eLogInfo,
 	eLogDebug,