nix_compat/
path_info.rs

1use crate::{narinfo::SignatureRef, nixbase32, nixhash::NixHash, store_path::StorePathRef};
2use serde::{Deserialize, Serialize};
3use std::collections::BTreeSet;
4
5/// Represents information about a Store Path that Nix provides inside the build
6/// if the exportReferencesGraph feature is used.
7/// This is not to be confused with the format Nix uses in its `nix path-info` command.
8/// It includes some more fields, like `registrationTime`, `signatures` and `ultimate`,
9/// does not include the `closureSize` and encodes `narHash` as SRI.
10#[derive(Clone, Debug, Eq, PartialEq, Hash, Serialize, Deserialize)]
11pub struct ExportedPathInfo<'a> {
12    #[serde(rename = "closureSize")]
13    pub closure_size: u64,
14
15    #[serde(
16        rename = "narHash",
17        serialize_with = "to_nix_nixbase32_string",
18        deserialize_with = "from_nix_hash_string"
19    )]
20    pub nar_sha256: [u8; 32],
21
22    #[serde(rename = "narSize")]
23    pub nar_size: u64,
24
25    #[serde(borrow)]
26    pub path: StorePathRef<'a>,
27
28    #[serde(borrow)]
29    #[serde(skip_serializing_if = "Option::is_none")]
30    pub deriver: Option<StorePathRef<'a>>,
31
32    /// The list of other Store Paths this Store Path refers to.
33    /// StorePathRef does Ord by the nixbase32-encoded string repr, so this is correct.
34    pub references: BTreeSet<StorePathRef<'a>>,
35    // more recent versions of Nix also have a `valid: true` field here, Nix 2.3 doesn't,
36    // and nothing seems to use it.
37    #[serde(default, skip_serializing_if = "Vec::is_empty")]
38    pub signatures: Vec<SignatureRef<'a>>,
39}
40
41/// ExportedPathInfo are ordered by their `path` field.
42impl Ord for ExportedPathInfo<'_> {
43    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
44        self.path.cmp(&other.path)
45    }
46}
47
48impl PartialOrd for ExportedPathInfo<'_> {
49    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
50        Some(self.cmp(other))
51    }
52}
53
54fn to_nix_nixbase32_string<S>(v: &[u8; 32], serializer: S) -> Result<S::Ok, S::Error>
55where
56    S: serde::Serializer,
57{
58    let string = NixHash::Sha256(*v).to_nix_nixbase32_string();
59    string.serialize(serializer)
60}
61
62/// The length of a sha256 digest, nixbase32-encoded.
63const NIXBASE32_SHA256_ENCODE_LEN: usize = nixbase32::encode_len(32);
64
65fn from_nix_hash_string<'de, D>(deserializer: D) -> Result<[u8; 32], D::Error>
66where
67    D: serde::Deserializer<'de>,
68{
69    let str: &'de str = Deserialize::deserialize(deserializer)?;
70    if let Some(digest_str) = str.strip_prefix("sha256:") {
71        return from_nix_nixbase32_string::<D>(digest_str);
72    }
73    if let Some(digest_str) = str.strip_prefix("sha256-") {
74        return from_sri_string::<D>(digest_str);
75    }
76    Err(serde::de::Error::invalid_value(
77        serde::de::Unexpected::Str(str),
78        &"extected a valid nixbase32 or sri narHash",
79    ))
80}
81
82fn from_sri_string<'de, D>(str: &str) -> Result<[u8; 32], D::Error>
83where
84    D: serde::Deserializer<'de>,
85{
86    let digest: [u8; 32] = data_encoding::BASE64
87        .decode(str.as_bytes())
88        .map_err(|_| {
89            serde::de::Error::invalid_value(
90                serde::de::Unexpected::Str(str),
91                &"valid base64 encoded string",
92            )
93        })?
94        .try_into()
95        .map_err(|_| {
96            serde::de::Error::invalid_value(serde::de::Unexpected::Str(str), &"valid digest len")
97        })?;
98
99    Ok(digest)
100}
101
102fn from_nix_nixbase32_string<'de, D>(str: &str) -> Result<[u8; 32], D::Error>
103where
104    D: serde::Deserializer<'de>,
105{
106    let digest_str: [u8; NIXBASE32_SHA256_ENCODE_LEN] =
107        str.as_bytes().try_into().map_err(|_| {
108            serde::de::Error::invalid_value(serde::de::Unexpected::Str(str), &"valid digest len")
109        })?;
110
111    let digest: [u8; 32] = nixbase32::decode_fixed(digest_str).map_err(|_| {
112        serde::de::Error::invalid_value(serde::de::Unexpected::Str(str), &"valid nixbase32")
113    })?;
114
115    Ok(digest)
116}
117
118#[cfg(test)]
119mod tests {
120    use hex_literal::hex;
121
122    use super::*;
123
124    /// Ensure we can create the same JSON as the exportReferencesGraph feature
125    #[test]
126    fn serialize_deserialize() {
127        // JSON extracted from a build of
128        // stdenv.mkDerivation { name = "hello"; __structuredAttrs = true; exportReferencesGraph.blub = [ pkgs.hello ]; nativeBuildInputs = [pkgs.jq]; buildCommand = "jq -rc .blub $NIX_ATTRS_JSON_FILE > $out"; }
129        let pathinfos_str_json = r#"[{"closureSize":1828984,"narHash":"sha256:11vm2x1ajhzsrzw7lsyss51mmr3b6yll9wdjn51bh7liwkpc8ila","narSize":1828984,"path":"/nix/store/7n0mbqydcipkpbxm24fab066lxk68aqk-libunistring-1.1","references":["/nix/store/7n0mbqydcipkpbxm24fab066lxk68aqk-libunistring-1.1"]},{"closureSize":32696176,"narHash":"sha256:0alzbhjxdcsmr1pk7z0bdh46r2xpq3xs3k9y82bi4bx5pklcvw5x","narSize":226560,"path":"/nix/store/dbghhbq1x39yxgkv3vkgfwbxrmw9nfzi-hello-2.12.1","references":["/nix/store/dbghhbq1x39yxgkv3vkgfwbxrmw9nfzi-hello-2.12.1","/nix/store/ddwyrxif62r8n6xclvskjyy6szdhvj60-glibc-2.39-5"]},{"closureSize":32469616,"narHash":"sha256:1zw5p05fh0k836ybfxkskv8apcv2m3pm2wa6y90wqn5w5kjyj13c","narSize":30119936,"path":"/nix/store/ddwyrxif62r8n6xclvskjyy6szdhvj60-glibc-2.39-5","references":["/nix/store/ddwyrxif62r8n6xclvskjyy6szdhvj60-glibc-2.39-5","/nix/store/rxganm4ibf31qngal3j3psp20mak37yy-xgcc-13.2.0-libgcc","/nix/store/s32cldbh9pfzd9z82izi12mdlrw0yf8q-libidn2-2.3.7"]},{"closureSize":159560,"narHash":"sha256:10q8iyvfmpfck3yiisnj1j8vp6lq3km17r26sr95zpdf9mgmk69s","narSize":159560,"path":"/nix/store/rxganm4ibf31qngal3j3psp20mak37yy-xgcc-13.2.0-libgcc","references":[]},{"closureSize":2190120,"narHash":"sha256:1cv997nzxbd91jhmzwnhxa1ahlzp5ffli8m4a5npcq8zg0vb1kwg","narSize":361136,"path":"/nix/store/s32cldbh9pfzd9z82izi12mdlrw0yf8q-libidn2-2.3.7","references":["/nix/store/7n0mbqydcipkpbxm24fab066lxk68aqk-libunistring-1.1","/nix/store/s32cldbh9pfzd9z82izi12mdlrw0yf8q-libidn2-2.3.7"]}]"#;
130
131        // We ensure it roundtrips (to check the sorting is correct)
132        let deserialized: BTreeSet<ExportedPathInfo> =
133            serde_json::from_str(pathinfos_str_json).expect("must serialize");
134
135        let serialized_again = serde_json::to_string(&deserialized).expect("must deserialize");
136        assert_eq!(pathinfos_str_json, serialized_again);
137
138        // Also compare one specific item to be populated as expected.
139        assert_eq!(
140            &ExportedPathInfo {
141                closure_size: 1828984,
142                nar_sha256: hex!(
143                    "8a46c4eee4911eb842b1b2f144a9376be45a43d1da6b7af8cffa43a942177587"
144                ),
145                nar_size: 1828984,
146                path: StorePathRef::from_bytes(
147                    b"7n0mbqydcipkpbxm24fab066lxk68aqk-libunistring-1.1"
148                )
149                .expect("must parse"),
150                deriver: None,
151                references: BTreeSet::from_iter([StorePathRef::from_bytes(
152                    b"7n0mbqydcipkpbxm24fab066lxk68aqk-libunistring-1.1"
153                )
154                .unwrap()]),
155                signatures: vec![],
156            },
157            deserialized.first().unwrap()
158        );
159    }
160
161    /// Ensure we can parse output from `nix path-info --json``
162    #[test]
163    fn serialize_deserialize_from_path_info() {
164        // JSON extracted from
165        // nix path-info /nix/store/z6r3bn5l51679pwkvh9nalp6c317z34m-libcxx-16.0.6-dev --json --closure-size
166        let pathinfos_str_json = r#"[{"closureSize":10756176,"deriver":"/nix/store/vs9976cyyxpykvdnlv7x85fpp3shn6ij-libcxx-16.0.6.drv","narHash":"sha256-E73Nt0NAKGxCnsyBFDUaCAbA+wiF5qjq1O9J7WrnT0E=","narSize":7020664,"path":"/nix/store/z6r3bn5l51679pwkvh9nalp6c317z34m-libcxx-16.0.6-dev","references":["/nix/store/lzzd5jgybnpfj86xkcpnd54xgwc4m457-libcxx-16.0.6"],"registrationTime":1730048276,"signatures":["cache.nixos.org-1:cTdhK6hnpPwtMXFX43CYb7v+CbpAusVI/MORZ3v5aHvpBYNg1MfBHVVeoexMBpNtHA8uFAn0aEsJaLXYIDhJDg=="],"valid":true}]"#;
167
168        let deserialized: BTreeSet<ExportedPathInfo> =
169            serde_json::from_str(pathinfos_str_json).expect("must serialize");
170
171        assert_eq!(
172            &ExportedPathInfo {
173                closure_size: 10756176,
174                nar_sha256: hex!(
175                    "13bdcdb74340286c429ecc8114351a0806c0fb0885e6a8ead4ef49ed6ae74f41"
176                ),
177                nar_size: 7020664,
178                path: StorePathRef::from_bytes(
179                    b"z6r3bn5l51679pwkvh9nalp6c317z34m-libcxx-16.0.6-dev"
180                )
181                .expect("must parse"),
182                deriver: Some(
183                    StorePathRef::from_bytes(
184                        b"vs9976cyyxpykvdnlv7x85fpp3shn6ij-libcxx-16.0.6.drv"
185                    )
186                    .expect("must parse")
187                ),
188                references: BTreeSet::from_iter([StorePathRef::from_bytes(
189                    b"lzzd5jgybnpfj86xkcpnd54xgwc4m457-libcxx-16.0.6"
190                )
191                .unwrap()]),
192                signatures: vec![SignatureRef::parse("cache.nixos.org-1:cTdhK6hnpPwtMXFX43CYb7v+CbpAusVI/MORZ3v5aHvpBYNg1MfBHVVeoexMBpNtHA8uFAn0aEsJaLXYIDhJDg==").expect("must parse")],
193            },
194            deserialized.first().unwrap()
195        );
196    }
197}
nix_compat/path_info.rs

nix_compat/
path_info.rs
