Add nonblocking version of GetLogName

Signed-off-by: Ravago Jones <ravagojones@gmail.com>
Change-Id: Ie91ac315bf659c4a85de1afe4fe6198c26ae747c
diff --git a/aos/logging/log_namer.h b/aos/logging/log_namer.h
index 72abf12..44e93bf 100644
--- a/aos/logging/log_namer.h
+++ b/aos/logging/log_namer.h
@@ -2,6 +2,7 @@
 #define AOS_LOGGING_LOG_NAMER_H_
 
 #include <string>
+#include <optional>
 
 namespace aos {
 namespace logging {
@@ -13,6 +14,11 @@
 // the form "/media/sda1/abc-123" and setup a symlink pointing to it at
 // "/media/sda1/abc-current".
 std::string GetLogName(const char *basename);
+
+// A nonblocking variant of GetLogName that you can poll instead of blocking for
+// the usb drive.
+std::optional<std::string> MaybeGetLogName(const char *basename);
+
 }  // namespace logging
 }  // namespace aos