pass instance of std::ostream for logging from API

Log.cpp

@@ -20,19 +20,24 @@ void LogMsg::Process()
 
 void Log::Flush ()
 {
-	if (m_LogFile)
-		m_LogFile->flush();
+	if (m_LogStream)
+		m_LogStream->flush();
 }
 
 void Log::SetLogFile (const std::string& fullFilePath)
 {
-	if (m_LogFile) delete m_LogFile;
-	m_LogFile = new std::ofstream (fullFilePath, std::ofstream::out | std::ofstream::binary | std::ofstream::trunc);
-	if (m_LogFile->is_open ())
+	auto logFile = new std::ofstream (fullFilePath, std::ofstream::out | std::ofstream::binary | std::ofstream::trunc);
+	if (logFile->is_open ())
+	{
+		SetLogStream (logFile);
 		LogPrint("Logging to file ",  fullFilePath, " enabled.");
+	}	
 	else
-	{
-		delete m_LogFile;
-		m_LogFile = nullptr;
+		delete logFile;
 }
+
+void Log::SetLogStream (std::ostream * logStream)
+{
+	if (m_LogStream) delete m_LogStream;	
+	m_LogStream = logStream;
 }

Log.h

@@ -32,11 +32,12 @@ class Log: public i2p::util::MsgQueue<LogMsg>
 {
 	public:
 
-		Log (): m_LogFile (nullptr) { SetOnEmpty (std::bind (&Log::Flush, this)); };
-		~Log () { delete m_LogFile; };
+		Log (): m_LogStream (nullptr) { SetOnEmpty (std::bind (&Log::Flush, this)); };
+		~Log () { delete m_LogStream; };
 
 		void SetLogFile (const std::string& fullFilePath);
-		std::ofstream * GetLogFile () const { return m_LogFile; };	
+		void SetLogStream (std::ostream * logStream);
+		std::ostream * GetLogStream () const { return m_LogStream; };	
 
 	private:
 
@@ -44,7 +45,7 @@ class Log: public i2p::util::MsgQueue<LogMsg>
 
 	private:
 		
-		std::ofstream * m_LogFile;
+		std::ostream * m_LogStream;
 };
 
 extern Log * g_Log;
@@ -59,6 +60,16 @@ inline void StartLog (const std::string& fullFilePath)
 	}	
 }
 
+inline void StartLog (std::ostream * s)
+{
+	if (!g_Log)
+	{	
+		g_Log = new Log ();
+		if (s)
+			g_Log->SetLogStream (s);
+	}	
+}
+
 inline void StopLog ()
 {
 	if (g_Log)
@@ -84,7 +95,7 @@ void LogPrint (std::stringstream& s, TValue arg, TArgs... args)
 template<typename... TArgs>
 void LogPrint (LogLevel level, TArgs... args) 
 {
-	LogMsg * msg = (g_Log && g_Log->GetLogFile ()) ? new LogMsg (*g_Log->GetLogFile (), level) : 
+	LogMsg * msg = (g_Log && g_Log->GetLogStream ()) ? new LogMsg (*g_Log->GetLogStream (), level) : 
 		new LogMsg (std::cout, level);
 	LogPrint (msg->s, args...);
 	msg->s << std::endl;

api/api.cpp

@@ -21,8 +21,11 @@ namespace api
 		i2p::context.Init ();	
 	}
 
-	void StartI2P ()
+	void StartI2P (std::ostream * logStream)
 	{
+		if (logStream)
+			StartLog (logStream);
+		else
 			StartLog (i2p::util::filesystem::GetAppName () + ".log");
 		i2p::data::netdb.Start();
 		LogPrint("NetDB started");

api/api.h

@@ -2,6 +2,7 @@
 #define API_H__
 
 #include <memory>
+#include <iostream>
 #include "Identity.h"
 #include "Destination.h"
 #include "Streaming.h"
@@ -12,7 +13,8 @@ namespace api
 {
 	// initialization start and stop	
 	void InitI2P (int argc, char* argv[], const char * appName);
-	void StartI2P ();
+	void StartI2P (std::ostream * logStream = nullptr);
+	// write system log to logStream, if not specified to <appName>.log in application's folder
 	void StopI2P ();
 
 	// destinations