//! This module constructs a [Derivation] by parsing its [ATerm][]
//! serialization.
//!
//! [ATerm]: http://program-transformation.org/Tools/ATermFormat.html
use bstr::BString;
use nom::bytes::complete::tag;
use nom::character::complete::char as nomchar;
use nom::combinator::{all_consuming, map_res};
use nom::multi::{separated_list0, separated_list1};
use nom::sequence::{delimited, preceded, separated_pair, terminated, tuple};
use std::collections::{BTreeMap, BTreeSet};
use thiserror;
use super::parse_error::{into_nomerror, ErrorKind, NomError, NomResult};
use super::{write, Derivation, NixHashWithMode, Output};
use crate::{aterm, nixhash};
#[derive(Debug, thiserror::Error)]
pub enum Error<I> {
#[error("parsing error: {0}")]
ParseError(NomError<I>),
#[error("premature EOF")]
Incomplete,
#[error("validation error: {0}")]
ValidationError(super::DerivationError),
}
pub(crate) fn parse(i: &[u8]) -> Result<Derivation, Error<&[u8]>> {
match all_consuming(parse_derivation)(i) {
Ok((rest, derivation)) => {
// this shouldn't happen, as all_consuming shouldn't return.
debug_assert!(rest.is_empty());
// invoke validate
derivation.validate(true).map_err(Error::ValidationError)?;
Ok(derivation)
}
Err(nom::Err::Incomplete(_)) => Err(Error::Incomplete),
Err(nom::Err::Error(e) | nom::Err::Failure(e)) => Err(Error::ParseError(e)),
}
}
/// Parse one output in ATerm. This is 4 string fields inside parans:
/// output name, output path, algo (and mode), digest.
/// Returns the output name and [Output] struct.
fn parse_output(i: &[u8]) -> NomResult<&[u8], (String, Output)> {
delimited(
nomchar('('),
map_res(
|i| {
tuple((
terminated(aterm::parse_string_field, nomchar(',')),
terminated(aterm::parse_string_field, nomchar(',')),
terminated(aterm::parse_string_field, nomchar(',')),
aterm::parse_bstr_field,
))(i)
.map_err(into_nomerror)
},
|(output_name, output_path, algo_and_mode, encoded_digest)| {
// convert these 4 fields into an [Output].
let hash_with_mode_res = {
if algo_and_mode.is_empty() && encoded_digest.is_empty() {
None
} else {
match data_encoding::HEXLOWER.decode(&encoded_digest) {
Ok(digest) => Some(NixHashWithMode::from_algo_mode_hash(
&algo_and_mode,
&digest,
)),
Err(e) => Some(Err(nixhash::Error::InvalidBase64Encoding(e))),
}
}
}
.transpose();
match hash_with_mode_res {
Ok(hash_with_mode) => Ok((
output_name,
Output {
path: output_path,
hash_with_mode,
},
)),
Err(e) => Err(nom::Err::Failure(NomError {
input: i,
code: ErrorKind::NixHashError(e),
})),
}
},
),
nomchar(')'),
)(i)
}
/// Parse multiple outputs in ATerm. This is a list of things acccepted by
/// parse_output, and takes care of turning the (String, Output) returned from
/// it to a BTreeMap.
/// We don't use parse_kv here, as it's dealing with 2-tuples, and these are
/// 4-tuples.
fn parse_outputs(i: &[u8]) -> NomResult<&[u8], BTreeMap<String, Output>> {
let res = delimited(
nomchar('['),
separated_list1(tag(","), parse_output),
nomchar(']'),
)(i);
match res {
Ok((rst, outputs_lst)) => {
let mut outputs: BTreeMap<String, Output> = BTreeMap::default();
for (output_name, output) in outputs_lst.into_iter() {
if outputs.contains_key(&output_name) {
return Err(nom::Err::Failure(NomError {
input: i,
code: ErrorKind::DuplicateMapKey(output_name),
}));
}
outputs.insert(output_name, output);
}
Ok((rst, outputs))
}
// pass regular parse errors along
Err(e) => Err(e),
}
}
fn parse_input_derivations(i: &[u8]) -> NomResult<&[u8], BTreeMap<String, Vec<String>>> {
parse_kv::<Vec<String>, _>(aterm::parse_str_list)(i)
}
pub fn parse_derivation(i: &[u8]) -> NomResult<&[u8], Derivation> {
use nom::Parser;
preceded(
tag(write::DERIVATION_PREFIX),
delimited(
// inside parens
nomchar('('),
// tuple requires all errors to be of the same type, so we need to be a
// bit verbose here wrapping generic IResult into [NomATermResult].
tuple((
// parse outputs
terminated(parse_outputs, nomchar(',')),
// // parse input derivations
terminated(parse_input_derivations, nomchar(',')),
// // parse input sources
|i| terminated(aterm::parse_str_list, nomchar(','))(i).map_err(into_nomerror),
// // parse system
|i| terminated(aterm::parse_string_field, nomchar(','))(i).map_err(into_nomerror),
// // parse builder
|i| terminated(aterm::parse_string_field, nomchar(','))(i).map_err(into_nomerror),
// // parse arguments
|i| terminated(aterm::parse_str_list, nomchar(','))(i).map_err(into_nomerror),
// parse environment
parse_kv::<BString, _>(aterm::parse_bstr_field),
)),
nomchar(')'),
)
.map(
|(
outputs,
input_derivations,
input_sources,
system,
builder,
arguments,
environment,
)| {
// All values in input_derivations need to be converted from
// Vec<String> to BTreeSet<String>
let mut input_derivations_new: BTreeMap<_, BTreeSet<_>> = BTreeMap::new();
for (k, v) in input_derivations.into_iter() {
let values_new: BTreeSet<_> = BTreeSet::from_iter(v.into_iter());
input_derivations_new.insert(k, values_new);
// TODO: actually check they're not duplicate in the parser side!
}
// Input sources need to be converted from Vec<_> to BTreeSet<_>
let input_sources_new: BTreeSet<_> = BTreeSet::from_iter(input_sources);
Derivation {
arguments,
builder,
environment,
input_derivations: input_derivations_new,
input_sources: input_sources_new,
outputs,
system,
}
},
),
)(i)
}
/// Parse a list of key/value pairs into a BTreeMap.
/// The parser for the values can be passed in.
/// In terms of ATerm, this is just a 2-tuple,
/// but we have the additional restriction that the first element needs to be
/// unique across all tuples.
pub(crate) fn parse_kv<'a, V, VF>(
vf: VF,
) -> impl FnMut(&'a [u8]) -> NomResult<&'a [u8], BTreeMap<String, V>> + 'static
where
VF: FnMut(&'a [u8]) -> nom::IResult<&'a [u8], V, nom::error::Error<&'a [u8]>> + Clone + 'static,
{
move |i|
// inside brackets
delimited(
nomchar('['),
|ii| {
let res = separated_list0(
nomchar(','),
// inside parens
delimited(
nomchar('('),
separated_pair(
aterm::parse_string_field,
nomchar(','),
vf.clone(),
),
nomchar(')'),
),
)(ii).map_err(into_nomerror);
match res {
Ok((rest, pairs)) => {
let mut kvs: BTreeMap<String, V> = BTreeMap::new();
for (k, v) in pairs.into_iter() {
// collect the 2-tuple to a BTreeMap,
// and fail if the key was already seen before.
if kvs.insert(k.clone(), v).is_some() {
return Err(nom::Err::Failure(NomError {
input: i,
code: ErrorKind::DuplicateMapKey(k),
}));
}
}
Ok((rest, kvs))
}
Err(e) => Err(e),
}
},
nomchar(']'),
)(i)
}
#[cfg(test)]
mod tests {
use std::collections::BTreeMap;
use crate::derivation::Output;
use bstr::{BString, ByteSlice};
use lazy_static::lazy_static;
use test_case::test_case;
lazy_static! {
static ref EXP_MULTI_OUTPUTS: BTreeMap<String, Output> = {
let mut b = BTreeMap::new();
b.insert(
"lib".to_string(),
Output {
path: "/nix/store/2vixb94v0hy2xc6p7mbnxxcyc095yyia-has-multi-out-lib"
.to_string(),
hash_with_mode: None,
},
);
b.insert(
"out".to_string(),
Output {
path: "/nix/store/55lwldka5nyxa08wnvlizyqw02ihy8ic-has-multi-out".to_string(),
hash_with_mode: None,
},
);
b
};
static ref EXP_AB_MAP: BTreeMap<String, BString> = {
let mut b = BTreeMap::new();
b.insert("a".to_string(), b"1".as_bstr().to_owned());
b.insert("b".to_string(), b"2".as_bstr().to_owned());
b
};
}
#[test_case(b"[(\"a\",\"1\"),(\"b\",\"2\")]", &EXP_AB_MAP, b""; "simple")]
fn parse_kv(input: &'static [u8], expected: &BTreeMap<String, BString>, exp_rest: &[u8]) {
let (rest, parsed) = super::parse_kv::<BString, _>(crate::aterm::parse_bstr_field)(input)
.expect("must parse");
assert_eq!(exp_rest, rest, "expected remainder");
assert_eq!(*expected, parsed);
}
#[test_case(
br#"("out","/nix/store/5vyvcwah9l9kf07d52rcgdk70g2f4y13-foo","","")"#,
("out".to_string(), Output {
path: "/nix/store/5vyvcwah9l9kf07d52rcgdk70g2f4y13-foo".to_string(),
hash_with_mode: None
}); "simple"
)]
#[test_case(
br#"("out","/nix/store/4q0pg5zpfmznxscq3avycvf9xdvx50n3-bar","r:sha256","08813cbee9903c62be4c5027726a418a300da4500b2d369d3af9286f4815ceba")"#,
("out".to_string(), Output {
path: "/nix/store/4q0pg5zpfmznxscq3avycvf9xdvx50n3-bar".to_string(),
hash_with_mode: Some(crate::derivation::NixHashWithMode::Recursive(
crate::nixhash::from_algo_and_digest (
crate::nixhash::HashAlgo::Sha256,
&data_encoding::HEXLOWER.decode(b"08813cbee9903c62be4c5027726a418a300da4500b2d369d3af9286f4815ceba").unwrap()
).unwrap()
)),
}); "fod"
)]
fn parse_output(input: &[u8], expected: (String, Output)) {
let (rest, parsed) = super::parse_output(input).expect("must parse");
assert!(rest.is_empty());
assert_eq!(expected, parsed);
}
#[test_case(
br#"[("lib","/nix/store/2vixb94v0hy2xc6p7mbnxxcyc095yyia-has-multi-out-lib","",""),("out","/nix/store/55lwldka5nyxa08wnvlizyqw02ihy8ic-has-multi-out","","")]"#,
&EXP_MULTI_OUTPUTS;
"multi-out"
)]
fn parse_outputs(input: &[u8], expected: &BTreeMap<String, Output>) {
let (rest, parsed) = super::parse_outputs(input).expect("must parse");
assert!(rest.is_empty());
assert_eq!(*expected, parsed);
}
}
