diff options
Diffstat (limited to 'tvix/eval/src/builtins/mod.rs')
-rw-r--r-- | tvix/eval/src/builtins/mod.rs | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/tvix/eval/src/builtins/mod.rs b/tvix/eval/src/builtins/mod.rs index 33abfe492d10..7a2f46e2d47d 100644 --- a/tvix/eval/src/builtins/mod.rs +++ b/tvix/eval/src/builtins/mod.rs @@ -5,12 +5,14 @@ use std::{ collections::{BTreeMap, HashMap}, + path::PathBuf, rc::Rc, }; use crate::{ errors::ErrorKind, value::{Builtin, CoercionKind, NixAttrs, NixList, NixString, Value}, + vm::VM, }; use crate::arithmetic_op; @@ -36,6 +38,30 @@ macro_rules! force { }; } +/// Coerce a Nix Value to a plain path, e.g. in order to access the file it +/// points to in an I/O builtin. This coercion can _never_ be performed in +/// a Nix program directly (i.e. the trick `path: /. + path` to convert from +/// a string to a path wouldn't hit this code), so the target file +/// doesn't need to be realised or imported into the Nix store. +pub fn coerce_value_to_path(v: &Value, vm: &mut VM) -> Result<PathBuf, ErrorKind> { + force!(vm, v, value, { + match value { + Value::Thunk(t) => coerce_value_to_path(&t.value(), vm), + Value::Path(p) => Ok(p.clone()), + _ => value + .coerce_to_string(CoercionKind::Weak, vm) + .map(|s| PathBuf::from(s.as_str())) + .and_then(|path| { + if path.is_absolute() { + Ok(path) + } else { + Err(ErrorKind::NotAnAbsolutePath(path)) + } + }), + } + }) +} + /// Return all pure builtins, that is all builtins that do not rely on /// I/O outside of the VM and which can be used in any contexts (e.g. /// WASM). |