Function extract_pkg_files

dev-scripts/src/sync/mirror/mod.rs:400–452

Use `tar` to extract relevant package metadata and script files from packages files. This function attempts to extract ".MTREE", ".BUILDINFO", ".PKGINFO" and ".INSTALL" files. Extracted files are placed in a directory structure that reflects the package's association with a package repository. ## Note Since some files are optional, we have to take a look at the files in that tarball to determin

(pkg: &Path, target_dir: &Path, repo_name: &str)

///
/// Panics if `pkg` points to a directory.
fn extract_pkg_files(pkg: &Path, target_dir: &Path, repo_name: &str) -> Result<(), Error> {
    let pkg_file_name = pkg
        .file_name()
        .expect("got directory when expecting file")
        .to_string_lossy()
        .to_string();
    let pkg_name = remove_tarball_suffix(pkg_file_name)?;

    // Peek into the pkg tar to see what kind of files we need to extract.
    let files = get_tar_file_list(pkg)?;

    // Create the target directory where all the files should be extracted to.
    let pkg_target_dir = target_dir.join(repo_name).join(pkg_name);
    create_dir_all(&pkg_target_dir).map_err(|source| Error::IoPath {
        path: pkg_target_dir.clone(),
        context: "recursively creating the directory".to_string(),
        source,
    })?;

    let mut cmd_args = vec![
        "-C".to_string(),
        pkg_target_dir.to_string_lossy().to_string(),
        "-xf".to_string(),
        pkg.to_string_lossy().to_string(),
    ];

    // Check for each of the known filetypes, whether it exists in the package.
    // If it does, add it to the tar command for extraction.
    for filetype in [
        MetadataFileName::Mtree.as_ref(),
        MetadataFileName::BuildInfo.as_ref(),
        MetadataFileName::PackageInfo.as_ref(),
        INSTALL_SCRIPTLET_FILE_NAME,
    ] {
        if files.contains(filetype) {
            cmd_args.push(filetype.to_string());
        }
    }

    // Run the extraction command
    let mut tar_command = Command::new("tar");
    tar_command.args(cmd_args);

    trace!("Running command: {tar_command:?}");
    let output = tar_command.output().map_err(|source| Error::IoPath {
        path: pkg.to_path_buf(),
        context: "extracting files".to_string(),
        source,
    })?;
    ensure_success(&output, format!("Extracting files from tar file {pkg:?}"))?;

    Ok(())
}

/// A small helper function that removes the `.pkg.tar.*` suffix of a tarball.
/// This is necessary to get the actual package name from a packages full file name.