nixide/rust/nix-expr/src/value.rs
Taeer Bar-Yam 48af0f9e41 error checking tweaks
(cherry picked from commit 6ac38519b710e69a0c30eb0fe8fc5fa712168cb8)
2025-10-04 02:30:46 +02:00

76 lines
2.2 KiB
Rust

use nix_c_raw as raw;
use nix_util::context::Context;
use std::ptr::{null_mut, NonNull};
// TODO: test: cloning a thunk does not duplicate the evaluation.
/** The type of a value (or thunk) */
#[derive(Eq, PartialEq, Debug)]
pub enum ValueType {
AttrSet,
Bool,
External,
Float,
Function,
Int,
List,
Null,
Path,
String,
Thunk,
Unknown,
}
impl ValueType {
pub(crate) fn from_raw(raw: raw::ValueType) -> ValueType {
match raw {
raw::ValueType_NIX_TYPE_ATTRS => ValueType::AttrSet,
raw::ValueType_NIX_TYPE_BOOL => ValueType::Bool,
raw::ValueType_NIX_TYPE_EXTERNAL => ValueType::External,
raw::ValueType_NIX_TYPE_FLOAT => ValueType::Float,
raw::ValueType_NIX_TYPE_FUNCTION => ValueType::Function,
raw::ValueType_NIX_TYPE_INT => ValueType::Int,
raw::ValueType_NIX_TYPE_LIST => ValueType::List,
raw::ValueType_NIX_TYPE_NULL => ValueType::Null,
raw::ValueType_NIX_TYPE_PATH => ValueType::Path,
raw::ValueType_NIX_TYPE_STRING => ValueType::String,
raw::ValueType_NIX_TYPE_THUNK => ValueType::Thunk,
// This would happen if a new type of value is added in Nix.
_ => ValueType::Unknown,
}
}
}
/* A pointer to a value or thunk, to be used with EvalState methods. */
pub struct Value {
inner: NonNull<raw::Value>,
}
impl Value {
pub(crate) fn new(inner: *mut raw::Value) -> Self {
Value {
inner: NonNull::new(inner).unwrap(),
}
}
pub(crate) fn raw_ptr(&self) -> *mut raw::Value {
self.inner.as_ptr()
}
}
impl Drop for Value {
fn drop(&mut self) {
unsafe {
// ignoring error because the only failure mode is leaking memory
raw::gc_decref(null_mut(), self.inner.as_ptr());
}
}
}
impl Clone for Value {
fn clone(&self) -> Self {
let context = Context::new();
unsafe { raw::gc_incref(context.ptr(), self.inner.as_ptr()) };
// can't return an error here, but we don't want to ignore the error either as it means we could use-after-free
context.check_err().unwrap();
Value { inner: self.inner }
}
}
// Tested in eval_state.rs