use crate::nixbase32;
use data_encoding::{DecodeError, BASE64};
use serde::{Deserialize, Serialize};
use std::{
fmt::{self, Display},
ops::Deref,
path::Path,
str::{self, FromStr},
};
use thiserror;
mod utils;
pub use utils::*;
pub const DIGEST_SIZE: usize = 20;
pub const ENCODED_DIGEST_SIZE: usize = nixbase32::encode_len(DIGEST_SIZE);
// The store dir prefix, without trailing slash.
// That's usually where the Nix store is mounted at.
pub const STORE_DIR: &str = "/nix/store";
pub const STORE_DIR_WITH_SLASH: &str = "/nix/store/";
/// Errors that can occur when parsing a literal store path
#[derive(Debug, PartialEq, Eq, thiserror::Error)]
pub enum Error {
#[error("Dash is missing between hash and name")]
MissingDash,
#[error("Hash encoding is invalid: {0}")]
InvalidHashEncoding(#[from] DecodeError),
#[error("Invalid length")]
InvalidLength,
#[error(
"Invalid name: \"{}\", character at position {} is invalid",
std::str::from_utf8(.0).unwrap_or(&BASE64.encode(.0)),
.1,
)]
InvalidName(Vec<u8>, u8),
#[error("Tried to parse an absolute path which was missing the store dir prefix.")]
MissingStoreDir,
}
/// Represents a path in the Nix store (a direct child of [STORE_DIR]).
///
/// It consists of a digest (20 bytes), and a name, which is a string.
/// The name may only contain ASCII alphanumeric, or one of the following
/// characters: `-`, `_`, `.`, `+`, `?`, `=`.
/// The name is usually used to describe the pname and version of a package.
/// Derivation paths can also be represented as store paths, their names just
/// end with the `.drv` prefix.
///
/// A [StorePath] does not encode any additional subpath "inside" the store
/// path.
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct StorePath<S>
where
S: std::cmp::Eq + std::cmp::PartialEq,
{
digest: [u8; DIGEST_SIZE],
name: S,
}
/// Like [StorePath], but without a heap allocation for the name.
/// Used by [StorePath] for parsing.
pub type StorePathRef<'a> = StorePath<&'a str>;
impl<S> StorePath<S>
where
S: std::cmp::Eq + Deref<Target = str>,
{
pub fn digest(&self) -> &[u8; DIGEST_SIZE] {
&self.digest
}
pub fn name(&self) -> &S {
&self.name
}
pub fn as_ref(&self) -> StorePathRef<'_> {
StorePathRef {
digest: self.digest,
name: &self.name,
}
}
pub fn to_owned(&self) -> StorePath<String> {
StorePath {
digest: self.digest,
name: self.name.to_string(),
}
}
/// Construct a [StorePath] by passing the `$digest-$name` string
/// that comes after [STORE_DIR_WITH_SLASH].
pub fn from_bytes<'a>(s: &'a [u8]) -> Result<Self, Error>
where
S: From<&'a str>,
{
// the whole string needs to be at least:
//
// - 32 characters (encoded hash)
// - 1 dash
// - 1 character for the name
if s.len() < ENCODED_DIGEST_SIZE + 2 {
Err(Error::InvalidLength)?
}
let digest = nixbase32::decode_fixed(&s[..ENCODED_DIGEST_SIZE])?;
if s[ENCODED_DIGEST_SIZE] != b'-' {
return Err(Error::MissingDash);
}
Ok(StorePath {
digest,
name: validate_name(&s[ENCODED_DIGEST_SIZE + 1..])?.into(),
})
}
/// Construct a [StorePathRef] from a name and digest.
/// The name is validated, and the digest checked for size.
pub fn from_name_and_digest<'a>(name: &'a str, digest: &[u8]) -> Result<Self, Error>
where
S: From<&'a str>,
{
let digest_fixed = digest.try_into().map_err(|_| Error::InvalidLength)?;
Self::from_name_and_digest_fixed(name, digest_fixed)
}
/// Construct a [StorePathRef] from a name and digest of correct length.
/// The name is validated.
pub fn from_name_and_digest_fixed<'a>(
name: &'a str,
digest: [u8; DIGEST_SIZE],
) -> Result<Self, Error>
where
S: From<&'a str>,
{
Ok(Self {
name: validate_name(name)?.into(),
digest,
})
}
/// Construct a [StorePathRef] from an absolute store path string.
/// This is equivalent to calling [StorePathRef::from_bytes], but stripping
/// the [STORE_DIR_WITH_SLASH] prefix before.
pub fn from_absolute_path<'a>(s: &'a [u8]) -> Result<Self, Error>
where
S: From<&'a str>,
{
match s.strip_prefix(STORE_DIR_WITH_SLASH.as_bytes()) {
Some(s_stripped) => Self::from_bytes(s_stripped),
None => Err(Error::MissingStoreDir),
}
}
/// Decompose a string into a [StorePath] and a [PathBuf] containing the
/// rest of the path, or an error.
#[cfg(target_family = "unix")]
pub fn from_absolute_path_full<'a, P>(path: &'a P) -> Result<(Self, &'a Path), Error>
where
S: From<&'a str>,
P: AsRef<std::path::Path> + ?Sized,
{
// strip [STORE_DIR_WITH_SLASH] from s
let p = path
.as_ref()
.strip_prefix(STORE_DIR_WITH_SLASH)
.map_err(|_e| Error::MissingStoreDir)?;
let mut it = Path::new(p).components();
// The first component of the rest must be parse-able as a [StorePath]
let first_component = it.next().ok_or(Error::InvalidLength)?;
let store_path = StorePath::from_bytes(first_component.as_os_str().as_encoded_bytes())?;
// collect rest
let rest_buf = it.as_path();
Ok((store_path, rest_buf))
}
/// Returns an absolute store path string.
/// That is just the string representation, prefixed with the store prefix
/// ([STORE_DIR_WITH_SLASH]),
pub fn to_absolute_path(&self) -> String
where
S: Display,
{
format!("{}{}", STORE_DIR_WITH_SLASH, self)
}
}
impl<S> PartialOrd for StorePath<S>
where
S: std::cmp::PartialEq + std::cmp::Eq,
{
fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
Some(self.cmp(other))
}
}
/// `StorePath`s are sorted by their reverse digest to match the sorting order
/// of the nixbase32-encoded string.
impl<S> Ord for StorePath<S>
where
S: std::cmp::PartialEq + std::cmp::Eq,
{
fn cmp(&self, other: &Self) -> std::cmp::Ordering {
self.digest.iter().rev().cmp(other.digest.iter().rev())
}
}
impl<'a, 'b: 'a> FromStr for StorePath<String> {
type Err = Error;
/// Construct a [StorePath] by passing the `$digest-$name` string
/// that comes after [STORE_DIR_WITH_SLASH].
fn from_str(s: &str) -> Result<Self, Self::Err> {
StorePath::<String>::from_bytes(s.as_bytes())
}
}
impl<'a, 'de: 'a, S> Deserialize<'de> for StorePath<S>
where
S: std::cmp::Eq + Deref<Target = str> + From<&'a str>,
{
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
D: serde::Deserializer<'de>,
{
let string: &'de str = Deserialize::deserialize(deserializer)?;
let stripped: Option<&str> = string.strip_prefix(STORE_DIR_WITH_SLASH);
let stripped: &str = stripped.ok_or_else(|| {
serde::de::Error::invalid_value(
serde::de::Unexpected::Str(string),
&"store path prefix",
)
})?;
StorePath::from_bytes(stripped.as_bytes()).map_err(|_| {
serde::de::Error::invalid_value(serde::de::Unexpected::Str(string), &"StorePath")
})
}
}
impl<S> Serialize for StorePath<S>
where
S: std::cmp::Eq + Deref<Target = str> + Display,
{
fn serialize<SR>(&self, serializer: SR) -> Result<SR::Ok, SR::Error>
where
SR: serde::Serializer,
{
let string: String = self.to_absolute_path();
string.serialize(serializer)
}
}
/// NAME_CHARS contains `true` for bytes that are valid in store path names.
static NAME_CHARS: [bool; 256] = {
let mut tbl = [false; 256];
let mut c = 0;
loop {
tbl[c as usize] = matches!(c, b'a'..=b'z' | b'A'..=b'Z' | b'0'..=b'9' | b'+' | b'-' | b'_' | b'?' | b'=' | b'.');
if c == u8::MAX {
break;
}
c += 1;
}
tbl
};
/// Checks a given &[u8] to match the restrictions for [StorePath::name], and
/// returns the name as string if successful.
pub(crate) fn validate_name(s: &(impl AsRef<[u8]> + ?Sized)) -> Result<&str, Error> {
let s = s.as_ref();
// Empty or excessively long names are not allowed.
if s.is_empty() || s.len() > 211 {
return Err(Error::InvalidLength);
}
let mut valid = true;
for &c in s {
valid = valid && NAME_CHARS[c as usize];
}
if !valid {
for (i, &c) in s.iter().enumerate() {
if !NAME_CHARS[c as usize] {
return Err(Error::InvalidName(s.to_vec(), i as u8));
}
}
unreachable!();
}
// SAFETY: We permit a subset of ASCII, which guarantees valid UTF-8.
Ok(unsafe { str::from_utf8_unchecked(s) })
}
impl<S> fmt::Display for StorePath<S>
where
S: fmt::Display + std::cmp::Eq,
{
/// The string representation of a store path starts with a digest (20
/// bytes), [crate::nixbase32]-encoded, followed by a `-`,
/// and ends with the name.
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{}-{}", nixbase32::encode(&self.digest), self.name)
}
}
#[cfg(test)]
mod tests {
use super::Error;
use std::cmp::Ordering;
use std::path::PathBuf;
use crate::store_path::{StorePath, StorePathRef, DIGEST_SIZE};
use hex_literal::hex;
use pretty_assertions::assert_eq;
use rstest::rstest;
use serde::Deserialize;
#[derive(Deserialize)]
/// An example struct, holding a StorePathRef.
/// Used to test deserializing StorePathRef.
struct Container<'a> {
#[serde(borrow)]
store_path: StorePathRef<'a>,
}
#[test]
fn happy_path() {
let example_nix_path_str =
"00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432";
let nixpath = StorePathRef::from_bytes(example_nix_path_str.as_bytes())
.expect("Error parsing example string");
let expected_digest: [u8; DIGEST_SIZE] = hex!("8a12321522fd91efbd60ebb2481af88580f61600");
assert_eq!("net-tools-1.60_p20170221182432", *nixpath.name());
assert_eq!(nixpath.digest, expected_digest);
assert_eq!(example_nix_path_str, nixpath.to_string())
}
#[test]
fn store_path_ordering() {
let store_paths = [
"/nix/store/0lk5dgi01r933abzfj9c9wlndg82yd3g-psutil-5.9.6.tar.gz.drv",
"/nix/store/1xj43bva89f9qmwm37zl7r3d7m67i9ck-shorttoc-1.3-tex.drv",
"/nix/store/2gb633czchi20jq1kqv70rx2yvvgins8-lifted-base-0.2.3.12.tar.gz.drv",
"/nix/store/2vksym3r3zqhp15q3fpvw2mnvffv11b9-docbook-xml-4.5.zip.drv",
"/nix/store/5q918awszjcz5720xvpc2czbg1sdqsf0-rust_renaming-0.1.0-lib",
"/nix/store/7jw30i342sr2p1fmz5xcfnch65h4zbd9-dbus-1.14.10.tar.xz.drv",
"/nix/store/96yqwqhnp3qya4rf4n0rcl0lwvrylp6k-eap8021x-222.40.1.tar.gz.drv",
"/nix/store/9gjqg36a1v0axyprbya1hkaylmnffixg-virtualenv-20.24.5.tar.gz.drv",
"/nix/store/a4i5mci2g9ada6ff7ks38g11dg6iqyb8-perl-5.32.1.drv",
"/nix/store/a5g76ljava4h5pxlggz3aqdhs3a4fk6p-ToolchainInfo.plist.drv",
"/nix/store/db46l7d6nswgz4ffp1mmd56vjf9g51v6-version.plist.drv",
"/nix/store/g6f7w20sd7vwy0rc1r4bfsw4ciclrm4q-crates-io-num_cpus-1.12.0.drv",
"/nix/store/iw82n1wwssb8g6772yddn8c3vafgv9np-bootstrap-stage1-sysctl-stdenv-darwin.drv",
"/nix/store/lp78d1y5wxpcn32d5c4r7xgbjwiw0cgf-logo.svg.drv",
"/nix/store/mf00ank13scv1f9l1zypqdpaawjhfr3s-python3.11-psutil-5.9.6.drv",
"/nix/store/mpfml61ra7pz90124jx9r3av0kvkz2w1-perl5.36.0-Encode-Locale-1.05",
"/nix/store/qhsvwx4h87skk7c4mx0xljgiy3z93i23-source.drv",
"/nix/store/riv7d73adim8hq7i04pr8kd0jnj93nav-fdk-aac-2.0.2.tar.gz.drv",
"/nix/store/s64b9031wga7vmpvgk16xwxjr0z9ln65-human-signals-5.0.0.tgz-extracted",
"/nix/store/w6svg3m2xdh6dhx0gl1nwa48g57d3hxh-thiserror-1.0.49",
];
for w in store_paths.windows(2) {
if w.len() < 2 {
continue;
}
let (pa, _) = StorePathRef::from_absolute_path_full(w[0]).expect("parseable");
let (pb, _) = StorePathRef::from_absolute_path_full(w[1]).expect("parseable");
assert_eq!(
Ordering::Less,
pa.cmp(&pb),
"{:?} not less than {:?}",
w[0],
w[1]
);
}
}
/// This is the store path *accepted* when `nix-store --add`'ing an
/// empty `.gitignore` file.
///
/// Nix 2.4 accidentally permitted this behaviour, but the revert came
/// too late to beat Hyrum's law. It is now considered permissible.
///
/// https://github.com/NixOS/nix/pull/9095 (revert)
/// https://github.com/NixOS/nix/pull/9867 (revert-of-revert)
#[test]
fn starts_with_dot() {
StorePathRef::from_bytes(b"fli4bwscgna7lpm7v5xgnjxrxh0yc7ra-.gitignore")
.expect("must succeed");
}
#[test]
fn empty_name() {
StorePathRef::from_bytes(b"00bgd045z0d4icpbc2yy-").expect_err("must fail");
}
#[test]
fn excessive_length() {
StorePathRef::from_bytes(b"00bgd045z0d4icpbc2yy-aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa")
.expect_err("must fail");
}
#[test]
fn invalid_hash_length() {
StorePathRef::from_bytes(b"00bgd045z0d4icpbc2yy-net-tools-1.60_p20170221182432")
.expect_err("must fail");
}
#[test]
fn invalid_encoding_hash() {
StorePathRef::from_bytes(
b"00bgd045z0d4icpbc2yyz4gx48aku4la-net-tools-1.60_p20170221182432",
)
.expect_err("must fail");
}
#[test]
fn more_than_just_the_bare_nix_store_path() {
StorePathRef::from_bytes(
b"00bgd045z0d4icpbc2yyz4gx48aku4la-net-tools-1.60_p20170221182432/bin/arp",
)
.expect_err("must fail");
}
#[test]
fn no_dash_between_hash_and_name() {
StorePathRef::from_bytes(b"00bgd045z0d4icpbc2yyz4gx48ak44lanet-tools-1.60_p20170221182432")
.expect_err("must fail");
}
#[test]
fn absolute_path() {
let example_nix_path_str =
"00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432";
let nixpath_expected =
StorePathRef::from_bytes(example_nix_path_str.as_bytes()).expect("must parse");
let nixpath_actual = StorePathRef::from_absolute_path(
"/nix/store/00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432".as_bytes(),
)
.expect("must parse");
assert_eq!(nixpath_expected, nixpath_actual);
assert_eq!(
"/nix/store/00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432",
nixpath_actual.to_absolute_path(),
);
}
#[test]
fn absolute_path_missing_prefix() {
assert_eq!(
Error::MissingStoreDir,
StorePathRef::from_absolute_path(b"foobar-123").expect_err("must fail")
);
}
#[test]
fn serialize_ref() {
let nixpath_actual = StorePathRef::from_bytes(
b"00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432",
)
.expect("can parse");
let serialized = serde_json::to_string(&nixpath_actual).expect("can serialize");
assert_eq!(
"\"/nix/store/00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432\"",
&serialized
);
}
#[test]
fn serialize_owned() {
let nixpath_actual = StorePathRef::from_bytes(
b"00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432",
)
.expect("can parse");
let serialized = serde_json::to_string(&nixpath_actual).expect("can serialize");
assert_eq!(
"\"/nix/store/00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432\"",
&serialized
);
}
#[test]
fn deserialize_ref() {
let store_path_str_json =
"\"/nix/store/00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432\"";
let store_path: StorePathRef<'_> =
serde_json::from_str(store_path_str_json).expect("valid json");
assert_eq!(
"/nix/store/00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432",
store_path.to_absolute_path()
);
}
#[test]
fn deserialize_ref_container() {
let str_json = "{\"store_path\":\"/nix/store/00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432\"}";
let container: Container<'_> = serde_json::from_str(str_json).expect("must deserialize");
assert_eq!(
"/nix/store/00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432",
container.store_path.to_absolute_path()
);
}
#[test]
fn deserialize_owned() {
let store_path_str_json =
"\"/nix/store/00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432\"";
let store_path: StorePath<String> =
serde_json::from_str(store_path_str_json).expect("valid json");
assert_eq!(
"/nix/store/00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432",
store_path.to_absolute_path()
);
}
#[rstest]
#[case::without_prefix(
"/nix/store/00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432",
StorePath::from_bytes(b"00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432").unwrap(), PathBuf::new())]
#[case::without_prefix_but_trailing_slash(
"/nix/store/00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432/",
StorePath::from_bytes(b"00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432").unwrap(), PathBuf::new())]
#[case::with_prefix(
"/nix/store/00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432/bin/arp",
StorePath::from_bytes(b"00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432").unwrap(), PathBuf::from("bin/arp"))]
#[case::with_prefix_and_trailing_slash(
"/nix/store/00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432/bin/arp/",
StorePath::from_bytes(b"00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432").unwrap(), PathBuf::from("bin/arp/"))]
fn from_absolute_path_full(
#[case] s: &str,
#[case] exp_store_path: StorePath<&str>,
#[case] exp_path: PathBuf,
) {
let (actual_store_path, actual_path) =
StorePath::from_absolute_path_full(s).expect("must succeed");
assert_eq!(exp_store_path, actual_store_path);
assert_eq!(exp_path, actual_path);
}
#[test]
fn from_absolute_path_errors() {
assert_eq!(
Error::InvalidLength,
StorePathRef::from_absolute_path_full("/nix/store/").expect_err("must fail")
);
assert_eq!(
Error::InvalidLength,
StorePathRef::from_absolute_path_full("/nix/store/foo").expect_err("must fail")
);
assert_eq!(
Error::MissingStoreDir,
StorePathRef::from_absolute_path_full(
"00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432"
)
.expect_err("must fail")
);
}
}
