Utilities for intercepting disk requests

Diskit (short for "Disc root kit") attempts to be an intransparent, rust-style root kit for intercepting and modifying requests to the hard drive. To use it, decide what you want to do with the intercepted requests and choose the appropriate diskit (e.g.: no interception -> StdDiskit; redirect to virtual file system -> VirtualDiskit; logging all requests -> LogDiskit), then route all requests through it:

use std::io::{Read, Write};
use diskit::{diskit_extend::DiskitExt, Diskit, VirtualDiskit};

fn main() -> Result<(), std::io::Error>
{
    // All requests are redircted to a virtual file system.
    let diskit = VirtualDiskit::default();

    // This writes "Hello, World!" in the newly created file "test.txt".
    let mut file1 = diskit.create("test.txt")?;
    file1.write_all(b"Hello, World!")?;

    // You can close `file1` and it still works:
    // file1.close()?;

    // This reads the just created file.
    let mut file2 = diskit.open("test.txt")?;
    let mut buf = String::new();
    file2.read_to_string(&mut buf)?;

    assert_eq!(buf, "Hello, World!");

    Ok(())
}

If you want to see how diskit would be used in a full program, see legacylisten, the program I wrote diskit for.

Making your own diskit

You can make your own diskit by implementing the Diskit trait.

Because a lot of stdlib types are intransparent, there are transparent replicas of them here that you're going to have to use. Most of these types have an inner type (e.g. File has FileInner) to make the Diskit trait object-safe and this library easy to use.

To make StdDiskit as overheadless as possible most types have an Option<StdsVersionOfThisType>, which should be None in your implementation.

If your diskit internally still needs to access the disk, please consider delegating these to an other diskit like LogDiskit does.

Size of a diskit

Diskits should (there is no way or reason to enforce it) be as small and cheaply cloneable as possible. This is because this library should be optimized for StdDiskit (as this is expected to be it's most used – albeit most useless – diskit) and while adding diskit support to legacylisten it became apparent that for good usability and performance diskits are cloned often and passed by value.

If your diskit is bigger than one usize consider wrapping it in an Arc.

Stability

Diskit is still in a very early version and nothing is stable, although I try to keep it stable.

Contributing

I have written that library specifically for legacylisten and added (mostly) only what I needed for that, so it's still lacking in a lot for normal usage. If you need an additional feature (or features) or otherwise have an idea how to make it better, please don't hesitate to share it or implement it yourself.