Check in file, requires the file to be checked out first.

Called to check out a file.

Called when the checked out version needs to be retrieved for a user.

Gets a list of all versions.

Called when a user wants to undo a checked out file.

Username of the user that changed the file.

If checked out; the date when the file was checked out.

If checked out; the username of the user who has this file checked out.

The username of the user that created this file.

Check whether the file is checked out.