UserDB Has Too Many Responsibilities ⟶ BackingStore

Should the file format be the responsibility of something that is mainly an in-memory database?

Attention

There are bugfixes ongoing in the file IO scene. Please wait until they are in place to not unnecessarily conflict by ripping out code under modification.

(See Existing Files Are Overwritten and UserDB::read(): What If Done Twice?)

BackingStore

Extract the bodies of UserDB::read() and UserDB::write() into a new class BackingStore. It is that class’s responsibility to implement the details of binary and CSV files IO.

Class UserDB gets passed a BackingStore instance in its read() and write() methods, as a replacement for a filename.

Like so,

class UserDB {
public:
    void read(BackingStore&, /*...*/);
    void write(BackingStore&, /*...*/);
};