nixide/rust/nix-store/src/store.rs
Philipp Zander de09abb084 support nix_store_open's params argument
(cherry picked from commit 3dd5137e33709559ffa152feb7ab508246adfb54)
2025-10-04 02:31:16 +02:00

147 lines
4.1 KiB
Rust

use anyhow::{bail, Result};
use lazy_static::lazy_static;
use nix_c_raw as raw;
use nix_util::context::Context;
use nix_util::result_string_init;
use nix_util::string_return::{callback_get_result_string, callback_get_result_string_data};
use std::ffi::{c_char, CString};
use std::ptr::null_mut;
use std::ptr::NonNull;
/* TODO make Nix itself thread safe */
lazy_static! {
static ref INIT: Result<()> = {
unsafe {
let context: Context = Context::new();
raw::libstore_init(context.ptr());
context.check_err()
}
};
}
struct StoreRef {
inner: NonNull<raw::Store>,
}
impl StoreRef {
pub fn ptr(&self) -> *mut raw::Store {
self.inner.as_ptr()
}
}
impl Drop for StoreRef {
fn drop(&mut self) {
unsafe {
raw::store_free(self.inner.as_ptr());
}
}
}
pub struct Store {
inner: StoreRef,
/* An error context to reuse. This way we don't have to allocate them for each store operation. */
context: Context,
}
impl Store {
pub fn open<'a, 'b>(
url: &str,
params: impl IntoIterator<Item = (&'a str, &'b str)>,
) -> Result<Self> {
let x = INIT.as_ref();
match x {
Ok(_) => {}
Err(e) => {
// Couldn't just clone the error, so we have to print it here.
bail!("nix_libstore_init error: {}", e);
}
}
let context: Context = Context::new();
let uri_ptr = CString::new(url)?;
// this intermediate value must be here and must not be moved
// because it owns the data the `*const c_char` pointers point to.
let params: Vec<(CString, CString)> = params
.into_iter()
.map(|(k, v)| Ok((CString::new(k)?, CString::new(v)?))) // to do. context
.collect::<Result<_>>()?;
// this intermediate value owns the data the `*mut *const c_char` pointer points to.
let mut params: Vec<_> = params
.iter()
.map(|(k, v)| [k.as_ptr(), v.as_ptr()])
.collect();
// this intermediate value owns the data the `*mut *mut *const c_char` pointer points to.
let mut params: Vec<*mut *const c_char> = params
.iter_mut()
.map(|t| t.as_mut_ptr())
.chain(std::iter::once(null_mut())) // signal the end of the array
.collect();
let store =
unsafe { raw::store_open(context.ptr(), uri_ptr.as_ptr(), params.as_mut_ptr()) };
context.check_err()?;
if store.is_null() {
panic!("nix_c_store_open returned a null pointer without an error");
}
let store = Store {
inner: StoreRef {
inner: NonNull::new(store).unwrap(),
},
context,
};
Ok(store)
}
pub fn raw_ptr(&self) -> *mut raw::Store {
self.inner.ptr()
}
pub fn get_uri(&self) -> Result<String> {
let mut r = result_string_init!();
unsafe {
raw::store_get_uri(
self.context.ptr(),
self.inner.ptr(),
Some(callback_get_result_string),
callback_get_result_string_data(&mut r),
)
};
self.context.check_err()?;
r
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn auto_works() {
let res = Store::open("auto");
res.unwrap();
}
#[test]
fn invalid_uri_fails() {
let res = Store::open("invalid://uri");
assert!(res.is_err());
}
#[test]
fn get_uri() {
let store = Store::open("auto").unwrap();
let uri = store.get_uri().unwrap();
assert!(!uri.is_empty());
// must be ascii
assert!(uri.is_ascii());
// usually something like "daemon", but that's not something we can check here.
println!("uri: {}", uri);
}
#[test]
#[ignore] // Needs network access
fn get_uri_nixos_cache() {
let store = Store::open("https://cache.nixos.org/").unwrap();
let uri = store.get_uri().unwrap();
assert_eq!(uri, "https://cache.nixos.org");
}
}