Synchronize access to the log's output stream with a mutex and document the write() method as being thread-safe.

src/Log.cpp

@@ -24,7 +24,9 @@ Log::~Log()
 
 void Log::open(const std::string& path)
 {
+	m_mutex.lock();
 	m_output.open(path.c_str(),std::ios_base::out | std::ios_base::app);
+	m_mutex.unlock();
 }
 
 void Log::writeToStream(std::ostream& stream, Type type, const char* text)
@@ -46,10 +48,12 @@ void Log::writeToStream(std::ostream& stream, Type type, const char* text)
 
 void Log::write(Type type, const char* text)
 {
+	m_mutex.lock();
 	writeToStream(std::cerr,type,text);
 	if (m_output.is_open())
 	{
 		writeToStream(m_output,type,text);
 	}
+	m_mutex.unlock();
 }
 

src/Log.h

@@ -3,6 +3,8 @@
 #include <string>
 #include <fstream>
 
+#include "tinythread.h"
+
 class Log
 {
 	public:
@@ -18,7 +20,9 @@ class Log
 
 		void open(const std::string& path);
 
+		/** Write @p text to the log.  This method is thread-safe. */
 		void write(Type type, const std::string& text);
+		/** Write @p text to the log.  This method is thread-safe. */
 		void write(Type type, const char* text);
 
 		static Log* instance();
@@ -26,6 +30,7 @@ class Log
 	private:
 		static void writeToStream(std::ostream& stream, Type type, const char* text);
 
+		tthread::mutex m_mutex;
 		std::ofstream m_output;
 };