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|
//! Contains builtins that fetch paths from the Internet
use crate::tvix_store_io::TvixStoreIO;
use bstr::ByteSlice;
use nix_compat::nixhash::{self, CAHash};
use nix_compat::store_path::{build_ca_path, StorePathRef};
use std::rc::Rc;
use tvix_eval::builtin_macros::builtins;
use tvix_eval::generators::GenCo;
use tvix_eval::{CatchableErrorKind, ErrorKind, NixContextElement, NixString, Value};
use super::utils::select_string;
use super::{DerivationError, FetcherError};
/// Attempts to mimic `nix::libutil::baseNameOf`
fn url_basename(s: &str) -> &str {
if s.is_empty() {
return "";
}
let mut last = s.len() - 1;
if s.chars().nth(last).unwrap() == '/' && last > 0 {
last -= 1;
}
if last == 0 {
return "";
}
let pos = match s[..=last].rfind('/') {
Some(pos) => {
if pos == last - 1 {
0
} else {
pos
}
}
None => 0,
};
&s[(pos + 1)..=last]
}
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum HashMode {
Flat,
Recursive,
}
/// Struct representing the arguments passed to fetcher functions
#[derive(Debug, PartialEq, Eq)]
struct FetchArgs {
url: String,
name: String,
hash: Option<CAHash>,
}
impl FetchArgs {
pub fn new(
url: String,
name: Option<String>,
sha256: Option<String>,
mode: HashMode,
) -> nixhash::Result<Self> {
Ok(Self {
name: name.unwrap_or_else(|| url_basename(&url).to_owned()),
url,
hash: sha256
.map(|h| {
let hash = nixhash::from_str(&h, Some("sha256"))?;
Ok(match mode {
HashMode::Flat => Some(nixhash::CAHash::Flat(hash)),
HashMode::Recursive => Some(nixhash::CAHash::Nar(hash)),
})
})
.transpose()?
.flatten(),
})
}
fn store_path(&self) -> Result<Option<StorePathRef>, ErrorKind> {
let Some(h) = &self.hash else {
return Ok(None);
};
build_ca_path(&self.name, h, Vec::<String>::new(), false)
.map(Some)
.map_err(|e| FetcherError::from(e).into())
}
async fn extract(
co: &GenCo,
args: Value,
default_name: Option<&str>,
mode: HashMode,
) -> Result<Result<Self, CatchableErrorKind>, ErrorKind> {
if let Ok(url) = args.to_str() {
return Ok(Ok(FetchArgs::new(
url.to_str()?.to_owned(),
None,
None,
mode,
)
.map_err(DerivationError::InvalidOutputHash)?));
}
let attrs = args.to_attrs().map_err(|_| ErrorKind::TypeError {
expected: "attribute set or string",
actual: args.type_of(),
})?;
let url = match select_string(co, &attrs, "url").await? {
Ok(s) => s.ok_or_else(|| ErrorKind::AttributeNotFound { name: "url".into() })?,
Err(cek) => return Ok(Err(cek)),
};
let name = match select_string(co, &attrs, "name").await? {
Ok(s) => s.or_else(|| default_name.map(|s| s.to_owned())),
Err(cek) => return Ok(Err(cek)),
};
let sha256 = match select_string(co, &attrs, "sha256").await? {
Ok(s) => s,
Err(cek) => return Ok(Err(cek)),
};
Ok(Ok(
FetchArgs::new(url, name, sha256, mode).map_err(DerivationError::InvalidOutputHash)?
))
}
}
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum FetchMode {
Url,
Tarball,
}
impl From<FetchMode> for HashMode {
fn from(value: FetchMode) -> Self {
match value {
FetchMode::Url => HashMode::Flat,
FetchMode::Tarball => HashMode::Recursive,
}
}
}
impl FetchMode {
fn default_name(self) -> Option<&'static str> {
match self {
FetchMode::Url => None,
FetchMode::Tarball => Some("source"),
}
}
}
fn string_from_store_path(store_path: StorePathRef) -> NixString {
NixString::new_context_from(
NixContextElement::Plain(store_path.to_absolute_path()).into(),
store_path.to_absolute_path(),
)
}
async fn fetch(
state: Rc<TvixStoreIO>,
co: GenCo,
args: Value,
mode: FetchMode,
) -> Result<Value, ErrorKind> {
let args = match FetchArgs::extract(&co, args, mode.default_name(), mode.into()).await? {
Ok(args) => args,
Err(cek) => return Ok(cek.into()),
};
if let Some(store_path) = args.store_path()? {
if state.store_path_exists(store_path).await? {
return Ok(string_from_store_path(store_path).into());
}
}
let hash = args.hash.as_ref().map(|h| h.hash());
let store_path = Rc::clone(&state).tokio_handle.block_on(state.fetch_url(
&args.url,
&args.name,
hash.as_deref(),
))?;
Ok(string_from_store_path(store_path.as_ref()).into())
}
#[allow(unused_variables)] // for the `state` arg, for now
#[builtins(state = "Rc<TvixStoreIO>")]
pub(crate) mod fetcher_builtins {
use super::*;
use tvix_eval::generators::Gen;
#[builtin("fetchurl")]
async fn builtin_fetchurl(
state: Rc<TvixStoreIO>,
co: GenCo,
args: Value,
) -> Result<Value, ErrorKind> {
fetch(state, co, args, FetchMode::Url).await
}
#[builtin("fetchTarball")]
async fn builtin_fetch_tarball(
state: Rc<TvixStoreIO>,
co: GenCo,
args: Value,
) -> Result<Value, ErrorKind> {
fetch(state, co, args, FetchMode::Tarball).await
}
#[builtin("fetchGit")]
async fn builtin_fetch_git(
state: Rc<TvixStoreIO>,
co: GenCo,
args: Value,
) -> Result<Value, ErrorKind> {
Err(ErrorKind::NotImplemented("fetchGit"))
}
}
#[cfg(test)]
mod tests {
use std::str::FromStr;
use nix_compat::store_path::StorePath;
use super::*;
#[test]
fn fetchurl_store_path() {
let url = "https://raw.githubusercontent.com/aaptel/notmuch-extract-patch/f732a53e12a7c91a06755ebfab2007adc9b3063b/notmuch-extract-patch";
let sha256 = "0nawkl04sj7psw6ikzay7kydj3dhd0fkwghcsf5rzaw4bmp4kbax";
let args = FetchArgs::new(url.into(), None, Some(sha256.into()), HashMode::Flat).unwrap();
assert_eq!(
args.store_path().unwrap().unwrap().to_owned(),
StorePath::from_str("06qi00hylriyfm0nl827crgjvbax84mz-notmuch-extract-patch").unwrap()
)
}
#[test]
fn fetch_tarball_store_path() {
let url = "https://github.com/NixOS/nixpkgs/archive/91050ea1e57e50388fa87a3302ba12d188ef723a.tar.gz";
let sha256 = "1hf6cgaci1n186kkkjq106ryf8mmlq9vnwgfwh625wa8hfgdn4dm";
let args = FetchArgs::new(
url.into(),
Some("source".into()),
Some(sha256.into()),
HashMode::Recursive,
)
.unwrap();
assert_eq!(
args.store_path().unwrap().unwrap().to_owned(),
StorePath::from_str("7adgvk5zdfq4pwrhsm3n9lzypb12gw0g-source").unwrap()
)
}
mod url_basename {
use super::*;
#[test]
fn empty_path() {
assert_eq!(url_basename(""), "");
}
#[test]
fn path_on_root() {
assert_eq!(url_basename("/dir"), "dir");
}
#[test]
fn relative_path() {
assert_eq!(url_basename("dir/foo"), "foo");
}
#[test]
fn root_with_trailing_slash() {
assert_eq!(url_basename("/"), "");
}
#[test]
fn trailing_slash() {
assert_eq!(url_basename("/dir/"), "dir");
}
}
}
|