fn unpack_package()

in src/storage.rs [2581:2626]

• 34 lines of code
• 4 McCabe index (conditional complexity)

fn unpack_package(tarball: &File, unpack_dir: &Path) -> Result<(), UnpackError> {
    // If we get here and the unpack_dir exists, this implies we had a previously failed fetch,
    // blast it away so we can have a clean slate!
    if unpack_dir.exists() {
        fs::remove_dir_all(unpack_dir)?;
    }
    fs::create_dir(unpack_dir)?;
    let gz = GzDecoder::new(tarball);
    let mut tar = Archive::new(gz);
    let prefix = unpack_dir.file_name().unwrap();
    let parent = unpack_dir.parent().unwrap();
    for entry in tar.entries()? {
        let mut entry = entry.map_err(UnpackError::ArchiveIterate)?;
        let entry_path = entry
            .path()
            .map_err(UnpackError::ArchiveEntry)?
            .into_owned();

        // We're going to unpack this tarball into the global source
        // directory, but we want to make sure that it doesn't accidentally
        // (or maliciously) overwrite source code from other crates. Cargo
        // itself should never generate a tarball that hits this error, and
        // crates.io should also block uploads with these sorts of tarballs,
        // but be extra sure by adding a check here as well.
        if !entry_path.starts_with(prefix) {
            return Err(UnpackError::InvalidPaths {
                entry_path,
                prefix: prefix.to_owned(),
            });
        }

        entry
            .unpack_in(parent)
            .map_err(|error| UnpackError::Unpack {
                entry_path: entry_path.clone(),
                error,
            })?;
    }

    create_unpack_lock(unpack_dir).map_err(|error| UnpackError::LockCreate {
        target: unpack_dir.to_owned(),
        error,
    })?;

    Ok(())
}