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use builtin_macros::builtins;
use smol_str::SmolStr;
use std::{
env,
rc::Rc,
time::{SystemTime, UNIX_EPOCH},
};
use crate::{
errors::ErrorKind,
io::FileType,
value::{NixAttrs, Thunk},
vm::VM,
Value,
};
#[builtins]
mod impure_builtins {
use super::*;
use crate::builtins::coerce_value_to_path;
#[builtin("getEnv")]
fn builtin_get_env(_: &mut VM, var: Value) -> Result<Value, ErrorKind> {
Ok(env::var(var.to_str()?).unwrap_or_else(|_| "".into()).into())
}
#[builtin("pathExists")]
fn builtin_path_exists(vm: &mut VM, s: Value) -> Result<Value, ErrorKind> {
let path = coerce_value_to_path(&s, vm)?;
vm.io().path_exists(path).map(Value::Bool)
}
#[builtin("readDir")]
fn builtin_read_dir(vm: &mut VM, path: Value) -> Result<Value, ErrorKind> {
let path = coerce_value_to_path(&path, vm)?;
let res = vm.io().read_dir(path)?.into_iter().map(|(name, ftype)| {
(
name,
Value::String(
SmolStr::new(match ftype {
FileType::Directory => "directory",
FileType::Regular => "regular",
FileType::Symlink => "symlink",
FileType::Unknown => "unknown",
})
.into(),
),
)
});
Ok(Value::attrs(NixAttrs::from_iter(res)))
}
#[builtin("readFile")]
fn builtin_read_file(vm: &mut VM, path: Value) -> Result<Value, ErrorKind> {
let path = coerce_value_to_path(&path, vm)?;
vm.io()
.read_to_string(path)
.map(|s| Value::String(s.into()))
}
}
/// Return all impure builtins, that is all builtins which may perform I/O
/// outside of the VM and so cannot be used in all contexts (e.g. WASM).
pub fn impure_builtins() -> Vec<(&'static str, Value)> {
let mut result = impure_builtins::builtins();
result.push((
"storeDir",
Value::Thunk(Thunk::new_suspended_native(Rc::new(
|vm: &mut VM| match vm.io().store_dir() {
None => Ok(Value::Null),
Some(dir) => Ok(Value::String(dir.into())),
},
))),
));
// currentTime pins the time at which evaluation was started
{
let seconds = match SystemTime::now().duration_since(UNIX_EPOCH) {
Ok(dur) => dur.as_secs() as i64,
// This case is hit if the system time is *before* epoch.
Err(err) => -(err.duration().as_secs() as i64),
};
result.push(("currentTime", Value::Integer(seconds)));
}
result
}
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