I'm conflicted between a "read once, use memory+pointers to files" and a "read when necessary" approach. The latter is of course much easier (no additional classes needed to store the whole dir structure), but IMO it is slower?

A little clarification: I'm writing a simple build system, that read a project file, checks if all files are present, and runs some compile steps. The file tree is static, so the first option doesn't need to be very dynamic and only needs to be built once every time the program is run. Thanks