--- a/src/utils/idfile.h
+++ b/src/utils/idfile.h
@@ -21,10 +21,13 @@
#include <string>
#include <list>
-// Return mime type for file or empty string. The system's file utility does
-// a bad job on mail folders. idFile only looks for mail file types for now,
-// but this may change
+// Look at data inside file or string, and return mime type or empty string.
+//
+// The system's file utility does a bad job on mail folders. idFile
+// only looks for mail file types for now, but this may change
+
extern std::string idFile(const char *fn);
+extern std::string idFileMem(const std::string& data);
// Return all types known to us
extern std::list<std::string> idFileAllTypes();