snix_glue/
fetchurl.rs

1//! This contains the code translating from a `builtin:derivation` [Derivation]
2//! to a [Fetch].
3use crate::fetchers::Fetch;
4use nix_compat::{derivation::Derivation, nixhash::CAHash};
5use tracing::instrument;
6use url::Url;
7
8/// Takes a derivation produced by a call to `builtin:fetchurl` and returns the
9/// synthesized [Fetch] for it, as well as the name.
10#[instrument]
11pub(crate) fn fetchurl_derivation_to_fetch(drv: &Derivation) -> Result<(String, Fetch), Error> {
12    if drv.builder != "builtin:fetchurl" {
13        return Err(Error::BuilderInvalid);
14    }
15    if !drv.arguments.is_empty() {
16        return Err(Error::ArgumentsInvalud);
17    }
18    if drv.system != "builtin" {
19        return Err(Error::SystemInvalid);
20    }
21
22    // ensure this is a fixed-output derivation
23    if drv.outputs.len() != 1 {
24        return Err(Error::NoFOD);
25    }
26    let out_output = &drv.outputs.get("out").ok_or(Error::NoFOD)?;
27    let ca_hash = out_output.ca_hash.clone().ok_or(Error::NoFOD)?;
28
29    let name: String = drv
30        .environment
31        .get("name")
32        .ok_or(Error::NameMissing)?
33        .to_owned()
34        .try_into()
35        .map_err(|_| Error::NameInvalid)?;
36
37    let url: Url = std::str::from_utf8(drv.environment.get("url").ok_or(Error::URLMissing)?)
38        .map_err(|_| Error::URLInvalid)?
39        .parse()
40        .map_err(|_| Error::URLInvalid)?;
41
42    match ca_hash {
43        CAHash::Flat(hash) => Ok((
44            name,
45            Fetch::URL {
46                url,
47                exp_hash: Some(hash),
48            },
49        )),
50        CAHash::Nar(hash) => {
51            if drv.environment.get("executable").map(|v| v.as_slice()) == Some(b"1") {
52                Ok((name, Fetch::Executable { url, hash }))
53            } else {
54                Ok((name, Fetch::NAR { url, hash }))
55            }
56        }
57        // you can't construct derivations containing this
58        CAHash::Text(_) => panic!("Snix bug: got CaHash::Text in drv"),
59    }
60}
61
62#[derive(Debug, thiserror::Error)]
63pub(crate) enum Error {
64    #[error("Invalid builder")]
65    BuilderInvalid,
66    #[error("invalid arguments")]
67    ArgumentsInvalud,
68    #[error("Invalid system")]
69    SystemInvalid,
70    #[error("Derivation is not fixed-output")]
71    NoFOD,
72    #[error("Missing URL")]
73    URLMissing,
74    #[error("Invalid URL")]
75    URLInvalid,
76    #[error("Missing Name")]
77    NameMissing,
78    #[error("Name invalid")]
79    NameInvalid,
80}
snix_glue/fetchurl.rs

snix_glue/
fetchurl.rs
