1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
|
use std::convert::Infallible;
use std::io;
use std::path::{Path, PathBuf};
use std::str::FromStr;
use crate::errors::ErrorKind;
#[derive(Debug, Clone, PartialEq, Eq)]
enum NixSearchPathEntry {
/// Resolve subdirectories of this path within `<...>` brackets. This
/// corresponds to bare paths within the `NIX_PATH` environment variable
///
/// For example, with `NixSearchPathEntry::Path("/example")` and the following
/// directory structure:
///
/// ```notrust
/// example
/// └── subdir
/// └── grandchild
/// ```
///
/// A Nix path literal `<subdir>` would resolve to `/example/subdir`, and a
/// Nix path literal `<subdir/grandchild>` would resolve to
/// `/example/subdir/grandchild`
Path(PathBuf),
/// Resolve paths starting with `prefix` as subdirectories of `path`. This
/// corresponds to `prefix=path` within the `NIX_PATH` environment variable.
///
/// For example, with `NixSearchPathEntry::Prefix { prefix: "prefix", path:
/// "/example" }` and the following directory structure:
///
/// ```notrust
/// example
/// └── subdir
/// └── grandchild
/// ```
///
/// A Nix path literal `<prefix/subdir>` would resolve to `/example/subdir`,
/// and a Nix path literal `<prefix/subdir/grandchild>` would resolve to
/// `/example/subdir/grandchild`
Prefix { prefix: PathBuf, path: PathBuf },
}
impl NixSearchPathEntry {
fn resolve(&self, lookup_path: &Path) -> io::Result<Option<PathBuf>> {
let resolve_in =
|parent: &Path, lookup_path: &Path| match parent.join(lookup_path).canonicalize() {
Ok(path) => Ok(Some(path)),
Err(e) if e.kind() == io::ErrorKind::NotFound => Ok(None),
Err(e) => Err(e),
};
match self {
NixSearchPathEntry::Path(p) => resolve_in(p, lookup_path),
NixSearchPathEntry::Prefix { prefix, path } => {
if let Ok(child_path) = lookup_path.strip_prefix(prefix) {
resolve_in(path, child_path)
} else {
Ok(None)
}
}
}
}
}
impl FromStr for NixSearchPathEntry {
type Err = Infallible;
fn from_str(s: &str) -> Result<Self, Self::Err> {
match s.split_once('=') {
Some((prefix, path)) => Ok(Self::Prefix {
prefix: prefix.into(),
path: path.into(),
}),
None => Ok(Self::Path(s.into())),
}
}
}
/// Struct implementing the format and path resolution rules of the `NIX_PATH`
/// environment variable.
///
/// This struct can be constructed by parsing a string using the [`FromStr`]
/// impl, or via [`str::parse`]. Nix `<...>` paths can then be resolved using
/// [`NixSearchPath::resolve`].
#[derive(Default, Debug, Clone, PartialEq, Eq)]
pub struct NixSearchPath {
entries: Vec<NixSearchPathEntry>,
}
impl NixSearchPath {
/// Attempt to resolve the given `path` within this [`NixSearchPath`] using the
/// path resolution rules for `<...>`-style paths
#[allow(dead_code)] // TODO(grfn)
pub fn resolve<P>(&self, path: P) -> Result<PathBuf, ErrorKind>
where
P: AsRef<Path>,
{
let path = path.as_ref();
for entry in &self.entries {
if let Some(p) = entry.resolve(path)? {
return Ok(p);
}
}
Err(ErrorKind::NixPathResolution(format!(
"path '{}' was not found in the Nix search path",
path.display()
)))
}
}
impl FromStr for NixSearchPath {
type Err = Infallible;
fn from_str(s: &str) -> Result<Self, Self::Err> {
let entries = s
.split(':')
.map(|s| s.parse())
.collect::<Result<Vec<_>, _>>()?;
Ok(NixSearchPath { entries })
}
}
#[cfg(test)]
mod tests {
use super::*;
mod parse {
use super::*;
#[test]
fn bare_paths() {
assert_eq!(
NixSearchPath::from_str("/foo/bar:/baz").unwrap(),
NixSearchPath {
entries: vec![
NixSearchPathEntry::Path("/foo/bar".into()),
NixSearchPathEntry::Path("/baz".into())
],
}
);
}
#[test]
fn mixed_prefix_and_paths() {
assert_eq!(
NixSearchPath::from_str("nixpkgs=/my/nixpkgs:/etc/nixos").unwrap(),
NixSearchPath {
entries: vec![
NixSearchPathEntry::Prefix {
prefix: "nixpkgs".into(),
path: "/my/nixpkgs".into()
},
NixSearchPathEntry::Path("/etc/nixos".into())
],
}
);
}
}
mod resolve {
use std::env::current_dir;
use path_clean::PathClean;
use super::*;
#[test]
fn simple_dir() {
let nix_search_path = NixSearchPath::from_str("./.").unwrap();
let res = nix_search_path.resolve("src").unwrap();
assert_eq!(res, current_dir().unwrap().join("src").clean());
}
#[test]
fn failed_resolution() {
let nix_search_path = NixSearchPath::from_str("./.").unwrap();
let err = nix_search_path.resolve("nope").unwrap_err();
assert!(
matches!(err, ErrorKind::NixPathResolution(..)),
"err = {err:?}"
);
}
#[test]
fn second_in_path() {
let nix_search_path = NixSearchPath::from_str("./.:/").unwrap();
let res = nix_search_path.resolve("etc").unwrap();
assert_eq!(res, Path::new("/etc"));
}
#[test]
fn prefix() {
let nix_search_path = NixSearchPath::from_str("/:tvix=.").unwrap();
let res = nix_search_path.resolve("tvix/src").unwrap();
assert_eq!(res, current_dir().unwrap().join("src").clean());
}
#[test]
fn matching_prefix() {
let nix_search_path = NixSearchPath::from_str("/:tvix=.").unwrap();
let res = nix_search_path.resolve("tvix").unwrap();
assert_eq!(res, current_dir().unwrap().clean());
}
}
}
|
