Given a path to a file, I would like to create this file, and the string of directories leading to it if they don't exist ; but I don't want any other instance of my program to be able to see the base directory existing without the file in it.
Basically, I want to atomically create the required directories and the file at once. From what I understood, it must be done in 2 steps (create directory, create file), so I was thinking about using a lock file, but the same problem applies : where do I create the lock file ? I don't know how many levels of folders need to be created, and at some point down the path, I might loose writing rights, so there is no "safe place" for a lock file.
Then I thought about using a lock directory instead of a lock file, but I couldn't find any "test and set" method to create directories (Directory.CreateDirectory(path) doesn't tell you if it did something).
So what's the right way to do it ?
Create the directory and file under a temporary name and atomically rename the directory to the final name.
Or use transactional NTFS (much harder).