Renew the updater branch

Now with some actual consensus on what the updater will do!

mmc_updater/src/Log.cpp

@@ -0,0 +1,65 @@
+#include "Log.h"
+
+#include "Platform.h"
+#include "StringUtils.h"
+#include "ProcessUtils.h"
+
+#include <string.h>
+#include <iostream>
+
+Log m_globalLog;
+
+Log* Log::instance()
+{
+	return &m_globalLog;
+}
+
+Log::Log()
+{
+}
+
+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)
+{
+	// Multiple processes may be writing to the same log file during
+	// an update.  No attempt is made to synchronize access to the file.
+	//
+	// Under Unix, appends to a single file on a local FS by multiple writers should be atomic
+	// provided that the length of 'text' is less than PIPE_BUF
+	//
+	switch (type)
+	{
+		case Info:
+			stream << "INFO  ";
+			break;
+		case Warn:
+			stream << "WARN  ";
+			break;
+		case Error:
+			stream << "ERROR ";
+			break;
+	}
+	stream << '(' << intToStr(ProcessUtils::currentProcessId()) << ") " << text << std::endl;
+}
+
+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();
+}
+