Renew the updater branch

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

mmc_updater/src/StandardDirs.cpp

@@ -0,0 +1,63 @@
+#include "StandardDirs.h"
+
+#include "FileUtils.h"
+#include "StringUtils.h"
+
+#ifdef PLATFORM_UNIX
+ #include <stdlib.h>
+ #include <pwd.h>
+ #include <unistd.h> 
+#endif
+
+#ifdef PLATFORM_WINDOWS
+#include <shlobj.h>
+#endif
+
+#ifdef PLATFORM_UNIX
+std::string StandardDirs::homeDir()
+{
+	std::string dir = notNullString(getenv("HOME"));
+	if (!dir.empty())
+	{
+		return dir;
+	}
+	else
+	{
+		// note: if this process has been elevated with sudo,
+		// this will return the home directory of the root user
+		struct passwd* userData = getpwuid(getuid());
+		return notNullString(userData->pw_dir);
+	}
+}
+#endif
+
+std::string StandardDirs::appDataPath(const std::string& organizationName,
+                        const std::string& appName)
+{
+#ifdef PLATFORM_LINUX
+	std::string xdgDataHome = notNullString(getenv("XDG_DATA_HOME"));
+	if (xdgDataHome.empty())
+	{
+		xdgDataHome = homeDir() + "/.local/share";
+	}
+	xdgDataHome += "/data/" + organizationName + '/' + appName;
+	return xdgDataHome;
+
+#elif defined(PLATFORM_MAC)
+	std::string path = applicationSupportFolderPath();
+	path += '/' + appName;
+	return path;
+#elif defined(PLATFORM_WINDOWS)
+	char buffer[MAX_PATH + 1];
+	if (SHGetFolderPath(0, CSIDL_LOCAL_APPDATA, 0 /* hToken */, SHGFP_TYPE_CURRENT, buffer) == S_OK)
+	{
+		std::string path = FileUtils::toUnixPathSeparators(notNullString(buffer));
+		path += '/' + organizationName + '/' + appName;
+		return path;
+	}
+	else
+	{
+		return std::string();
+	}
+#endif
+}