colmena/src/nix/store.rs
2022-07-29 22:13:09 -07:00

154 lines
4 KiB
Rust

use std::convert::{TryFrom, TryInto};
use std::fmt;
use std::marker::PhantomData;
use std::ops::Deref;
use std::path::{Path, PathBuf};
use serde::{Deserialize, Serialize};
use tokio::process::Command;
use super::Host;
use crate::error::{ColmenaError, ColmenaResult};
use crate::util::CommandExt;
/// A Nix store path.
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub struct StorePath(PathBuf);
/// A store derivation (.drv) that will result in a T when built.
#[derive(Debug)]
pub struct StoreDerivation<T: TryFrom<BuildResult<T>>> {
path: StorePath,
_target: PhantomData<T>,
}
/// Results of a build/realization.
pub struct BuildResult<T: TryFrom<BuildResult<T>>> {
results: Vec<StorePath>,
_derivation: PhantomData<T>,
}
impl StorePath {
/// Returns the raw store path.
pub fn as_path(&self) -> &Path {
&self.0
}
/// Determines whether the path points to a derivation.
pub fn is_derivation(&self) -> bool {
if let Some(ext) = self.0.extension() {
ext == "drv"
} else {
false
}
}
/// Returns the immediate dependencies of the store path.
pub async fn references(&self) -> ColmenaResult<Vec<StorePath>> {
let references = Command::new("nix-store")
.args(&["--query", "--references"])
.arg(&self.0)
.capture_output()
.await?
.trim_end()
.split('\n')
.map(|p| StorePath(PathBuf::from(p)))
.collect();
Ok(references)
}
/// Converts the store path into a store derivation.
pub fn into_derivation<T: TryFrom<BuildResult<T>>>(self) -> ColmenaResult<StoreDerivation<T>> {
if self.is_derivation() {
Ok(StoreDerivation::<T>::from_store_path_unchecked(self))
} else {
Err(ColmenaError::NotADerivation { store_path: self })
}
}
}
impl Deref for StorePath {
type Target = Path;
fn deref(&self) -> &Self::Target {
&self.0
}
}
impl TryFrom<String> for StorePath {
type Error = ColmenaError;
fn try_from(s: String) -> ColmenaResult<Self> {
if s.starts_with("/nix/store/") {
Ok(Self(s.into()))
} else {
Err(ColmenaError::InvalidStorePath)
}
}
}
impl From<StorePath> for PathBuf {
fn from(sp: StorePath) -> Self {
sp.0
}
}
impl<T: TryFrom<BuildResult<T>>> Clone for StoreDerivation<T> {
fn clone(&self) -> Self {
Self {
path: self.path.clone(),
_target: PhantomData,
}
}
}
impl<T: TryFrom<BuildResult<T>>> StoreDerivation<T> {
/// Returns the store path.
pub fn as_store_path(&self) -> &StorePath {
&self.path
}
fn from_store_path_unchecked(path: StorePath) -> Self {
Self {
path,
_target: PhantomData,
}
}
}
impl<T: TryFrom<BuildResult<T>, Error = ColmenaError>> StoreDerivation<T> {
/// Builds the store derivation on a host, resulting in a T.
pub async fn realize(&self, host: &mut Box<dyn Host>) -> ColmenaResult<T> {
let paths: Vec<StorePath> = host.realize(&self.path).await?;
let result = BuildResult {
results: paths,
_derivation: PhantomData,
};
result.try_into()
}
/// Builds the store derivation on a host without copying the results back.
pub async fn realize_remote(&self, host: &mut Box<dyn Host>) -> ColmenaResult<T> {
let paths: Vec<StorePath> = host.realize_remote(&self.path).await?;
let result = BuildResult {
results: paths,
_derivation: PhantomData,
};
result.try_into()
}
}
impl<T: TryFrom<BuildResult<T>>> fmt::Display for StoreDerivation<T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{:?}", self.path)
}
}
impl<T: TryFrom<BuildResult<T>, Error = ColmenaError>> BuildResult<T> {
pub fn paths(&self) -> &[StorePath] {
self.results.as_slice()
}
}