feat: persist JsRuntime

Cargo.lock

@@ -1053,6 +1053,7 @@ dependencies = [
  "itertools 0.14.0",
  "mimalloc",
  "nix-js-macros",
+ "pin-project",
  "regex",
  "rnix",
  "rustyline",

nix-js/Cargo.toml

@@ -17,6 +17,7 @@ derive_more = { version = "2", features = ["full"] }
 thiserror = "2"
 string-interner = "0.19"
 itertools = "0.14"
+pin-project = "1"
 
 deno_core = "0.376"
 deno_error = "0.7"

nix-js/src/context.rs

@@ -1,6 +1,8 @@
 use std::path::PathBuf;
+use std::pin::Pin;
 use std::ptr::NonNull;
 
+use deno_core::JsRuntime;
 use hashbrown::HashMap;
 use itertools::Itertools as _;
 use string_interner::DefaultStringInterner;
@@ -15,14 +17,55 @@ use downgrade::DowngradeCtx;
 mod downgrade;
 
 pub struct Context {
+    ctx: Pin<Box<Ctx>>,
+    pub(crate) js_runtime: JsRuntime,
+}
+
+impl Default for Context {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl Context {
+    pub fn new() -> Self {
+        let mut ctx = Box::pin(Ctx::new());
+        let ptr = unsafe { NonNull::new_unchecked(Pin::get_unchecked_mut(ctx.as_mut())) };
+        let js_runtime = crate::runtime::new_js_runtime(ptr);
+
+        Self { ctx, js_runtime }
+    }
+
+    pub fn eval_code(&mut self, expr: &str) -> Result<Value> {
+        // Initialize `path_stack` with current directory for relative path resolution
+        let mut guard = PathDropGuard::new_cwd(self.ctx.as_mut());
+        let ctx = guard.as_ctx();
+
+        let root = rnix::Root::parse(expr);
+        if !root.errors().is_empty() {
+            return Err(Error::parse_error(root.errors().iter().join("; ")));
+        }
+        let root = ctx.as_mut().downgrade_ctx().downgrade(root.tree().expr().unwrap())?;
+        let code = ctx.get_ir(root).compile(Pin::get_ref(ctx.as_ref()));
+        let code = format!("Nix.force({})", code);
+        println!("[DEBUG] generated code: {}", &code);
+        crate::runtime::run(code, &mut self.js_runtime)
+    }
+}
+
+#[pin_project::pin_project(PinnedDrop)]
+pub struct Ctx {
     irs: Vec<Ir>,
     symbols: DefaultStringInterner,
     global: NonNull<HashMap<SymId, ExprId>>,
     path_stack: Vec<PathBuf>,
+    #[pin]
+    _marker: std::marker::PhantomPinned,
 }
 
-impl Drop for Context {
+#[pin_project::pinned_drop]
-    fn drop(&mut self) {
+impl PinnedDrop for Ctx {
+    fn drop(self: Pin<&mut Self>) {
         unsafe {
             drop(Box::from_raw(self.global.as_ptr()));
         }
@@ -30,32 +73,32 @@ impl Drop for Context {
 }
 
 pub struct PathDropGuard<'ctx> {
-    ctx: &'ctx mut Context,
+    ctx: Pin<&'ctx mut Ctx>,
 }
 
 impl<'ctx> PathDropGuard<'ctx> {
-    pub fn new(path: PathBuf, ctx: &'ctx mut Context) -> Self {
+    pub fn new(path: PathBuf, mut ctx: Pin<&'ctx mut Ctx>) -> Self {
-        ctx.path_stack.push(path);
+        ctx.as_mut().project().path_stack.push(path);
         Self { ctx }
     }
-    pub fn new_cwd(ctx: &'ctx mut Context) -> Self {
+    pub fn new_cwd(mut ctx: Pin<&'ctx mut Ctx>) -> Self {
         let cwd = std::env::current_dir().unwrap();
         let virtual_file = cwd.join("__eval__.nix");
-        ctx.path_stack.push(virtual_file);
+        ctx.as_mut().project().path_stack.push(virtual_file);
         Self { ctx }
     }
-    pub fn as_ctx(&mut self) -> &mut Context {
+    pub fn as_ctx<'a>(&'a mut self) -> &'a mut Pin<&'ctx mut Ctx> {
-        self.ctx
+        &mut self.ctx
     }
 }
 
 impl Drop for PathDropGuard<'_> {
     fn drop(&mut self) {
-        self.ctx.path_stack.pop();
+        self.ctx.as_mut().project().path_stack.pop();
     }
 }
 
-impl Default for Context {
+impl Default for Ctx {
     fn default() -> Self {
         use crate::ir::{Attr, Builtins, Select, ToIr};
 
@@ -111,45 +154,33 @@ impl Default for Context {
             irs,
             global: unsafe { NonNull::new_unchecked(Box::leak(Box::new(global))) },
             path_stack: Vec::new(),
+            _marker: std::marker::PhantomPinned,
         }
     }
 }
 
-impl Context {
+impl Ctx {
     pub fn new() -> Self {
         Self::default()
     }
 
-    pub fn downgrade_ctx<'a>(&'a mut self) -> DowngradeCtx<'a> {
+    pub fn downgrade_ctx<'a>(self: Pin<&'a mut Self>) -> DowngradeCtx<'a> {
         // SAFETY: `global` is readonly
         let global_ref = unsafe { self.global.as_ref() };
         DowngradeCtx::new(self, global_ref)
     }
 
-    pub fn eval_code(&mut self, expr: &str) -> Result<Value> {
-        // Initialize `path_stack` with current directory for relative path resolution
-        let mut guard = PathDropGuard::new_cwd(self);
-        let ctx = guard.as_ctx();
-
-        let root = rnix::Root::parse(expr);
-        if !root.errors().is_empty() {
-            return Err(Error::parse_error(root.errors().iter().join("; ")));
-        }
-        let root = ctx
-            .downgrade_ctx()
-            .downgrade(root.tree().expr().unwrap())?;
-        let code = ctx.get_ir(root).compile(ctx);
-        let code = format!("Nix.force({})", code);
-        println!("[DEBUG] generated code: {}", &code);
-        crate::runtime::run(code, ctx)
-    }
-
     pub fn get_current_dir(&self) -> PathBuf {
-        self.path_stack.last().unwrap().parent().unwrap().to_path_buf()
+        self.path_stack
+            .last()
+            .unwrap()
+            .parent()
+            .unwrap()
+            .to_path_buf()
     }
 }
 
-impl CodegenContext for Context {
+impl CodegenContext for Ctx {
     fn get_ir(&self, id: ExprId) -> &Ir {
         self.irs.get(id.0).unwrap()
     }
@@ -436,7 +467,9 @@ mod test {
     fn test_builtin_in_with() {
         // Test builtins with 'with' expression
         assert_eq!(
-            Context::new().eval_code("with builtins; add 10 20").unwrap(),
+            Context::new()
+                .eval_code("with builtins; add 10 20")
+                .unwrap(),
             Value::Const(Const::Int(30))
         );
     }
@@ -460,11 +493,15 @@ mod test {
             Value::Const(Const::Bool(true))
         );
         assert_eq!(
-            Context::new().eval_code("builtins.isAttrs { a = 1; }").unwrap(),
+            Context::new()
+                .eval_code("builtins.isAttrs { a = 1; }")
+                .unwrap(),
             Value::Const(Const::Bool(true))
         );
         assert_eq!(
-            Context::new().eval_code("builtins.isFunction (x: x)").unwrap(),
+            Context::new()
+                .eval_code("builtins.isFunction (x: x)")
+                .unwrap(),
             Value::Const(Const::Bool(true))
         );
         assert_eq!(
@@ -553,7 +590,9 @@ mod test {
     fn test_free_global_shadowing() {
         // Test shadowing of free globals
         assert_eq!(
-            Context::new().eval_code("let true = false; in true").unwrap(),
+            Context::new()
+                .eval_code("let true = false; in true")
+                .unwrap(),
             Value::Const(Const::Bool(false))
         );
         assert_eq!(
@@ -699,7 +738,10 @@ mod test {
 
         assert_eq!(ctx.eval_code("7 / 3").unwrap(), Value::Const(Const::Int(2)));
 
-        assert_eq!(ctx.eval_code("10 / 3").unwrap(), Value::Const(Const::Int(3)));
+        assert_eq!(
+            ctx.eval_code("10 / 3").unwrap(),
+            Value::Const(Const::Int(3))
+        );
 
         // Float division returns float
         assert_eq!(
@@ -712,7 +754,10 @@ mod test {
             Value::Const(Const::Float(3.5))
         );
 
-        assert_eq!(ctx.eval_code("(-7) / 3").unwrap(), Value::Const(Const::Int(-2)));
+        assert_eq!(
+            ctx.eval_code("(-7) / 3").unwrap(),
+            Value::Const(Const::Int(-2))
+        );
     }
 
     #[test]

nix-js/src/context/downgrade.rs

@@ -1,9 +1,11 @@
+use std::pin::Pin;
+
 use hashbrown::HashMap;
 
 use crate::error::{Error, Result};
 use crate::ir::{ArgId, Downgrade, DowngradeContext, ExprId, Ir, SymId, ToIr};
 
-use super::Context;
+use super::Ctx;
 
 enum Scope<'ctx> {
     Global(&'ctx HashMap<SymId, ExprId>),
@@ -29,14 +31,14 @@ impl<'a, 'ctx> ScopeGuard<'a, 'ctx> {
 }
 
 pub struct DowngradeCtx<'ctx> {
-    ctx: &'ctx mut Context,
+    ctx: Pin<&'ctx mut Ctx>,
     irs: Vec<Option<Ir>>,
     scopes: Vec<Scope<'ctx>>,
     arg_id: usize,
 }
 
 impl<'ctx> DowngradeCtx<'ctx> {
-    pub fn new(ctx: &'ctx mut Context, global: &'ctx HashMap<SymId, ExprId>) -> Self {
+    pub fn new(ctx: Pin<&'ctx mut Ctx>, global: &'ctx HashMap<SymId, ExprId>) -> Self {
         Self {
             scopes: vec![Scope::Global(global)],
             irs: vec![],
@@ -59,7 +61,7 @@ impl DowngradeContext for DowngradeCtx<'_> {
     }
 
     fn new_sym(&mut self, sym: String) -> SymId {
-        self.ctx.symbols.get_or_intern(sym)
+        self.ctx.as_mut().project().symbols.get_or_intern(sym)
     }
 
     fn get_sym(&self, id: SymId) -> &str {
@@ -133,6 +135,8 @@ impl DowngradeContext for DowngradeCtx<'_> {
     fn downgrade(mut self, root: rnix::ast::Expr) -> Result<ExprId> {
         let root = root.downgrade(&mut self)?;
         self.ctx
+            .as_mut()
+            .project()
             .irs
             .extend(self.irs.into_iter().map(Option::unwrap));
         Ok(root)

nix-js/src/ir/downgrade.rs

@@ -94,14 +94,12 @@ impl<Ctx: DowngradeContext> Downgrade<Ctx> for ast::Path {
             parts_ast
                 .into_iter()
                 .map(|part| match part {
-                    ast::InterpolPart::Literal(lit) => {
+                    ast::InterpolPart::Literal(lit) => Ok(ctx.new_expr(
-                        Ok(ctx.new_expr(
                         Str {
                             val: lit.to_string(),
                         }
                         .to_ir(),
-                        ))
+                    )),
-                    }
                     ast::InterpolPart::Interpolation(interpol) => {
                         interpol.expr().unwrap().downgrade(ctx)
                     }

nix-js/src/runtime.rs

@@ -1,15 +1,14 @@
 use std::borrow::Cow;
 use std::cell::RefCell;
+use std::pin::Pin;
 use std::ptr::NonNull;
 use std::sync::Once;
 
-use deno_core::{
+use deno_core::{Extension, ExtensionFileSource, JsRuntime, OpState, RuntimeOptions, v8};
-    Extension, ExtensionFileSource, JsRuntime, OpState, RuntimeOptions, v8
-};
 use deno_error::js_error_wrapper;
 
 use crate::codegen::{CodegenContext, Compile};
-use crate::context::{Context, PathDropGuard};
+use crate::context::{Ctx, PathDropGuard};
 use crate::error::{Error, Result};
 use crate::ir::DowngradeContext;
 use crate::value::{AttrSet, Const, List, Symbol, Value};
@@ -18,12 +17,10 @@ pub trait RuntimeContext {
     fn split<Ctx: DowngradeContext>(&mut self) -> (&mut JsRuntime, &mut Ctx);
 }
 
-fn nix_runtime(ctx: &mut Context) -> Extension {
+fn nix_runtime(ctx: NonNull<Ctx>) -> Extension {
     const ESM: &[ExtensionFileSource] =
         &deno_core::include_js_files!(nix_runtime dir "runtime-ts/dist", "runtime.js");
 
-    // TODO: SAFETY
-    let ptr = unsafe { NonNull::new_unchecked(ctx) };
     Extension {
         name: "nix_runtime",
         esm_files: Cow::Borrowed(ESM),
@@ -35,7 +32,7 @@ fn nix_runtime(ctx: &mut Context) -> Extension {
             op_resolve_path(),
         ]),
         op_state_fn: Some(Box::new(move |state| {
-            state.put(RefCell::new(ptr));
+            state.put(RefCell::new(ctx));
         })),
         enabled: true,
         ..Default::default()
@@ -74,28 +71,22 @@ js_error_wrapper!(SimpleErrorWrapper, NixError, "EvalError");
 #[deno_core::op2]
 #[string]
 fn op_import(state: &mut OpState, #[string] path: String) -> std::result::Result<String, NixError> {
-    let mut ptr = state.borrow::<RefCell<NonNull<Context>>>().borrow_mut();
+    let mut ptr = state.borrow::<RefCell<NonNull<Ctx>>>().borrow_mut();
-    let ctx = unsafe { ptr.as_mut() };
+    let ctx = unsafe { Pin::new_unchecked(ptr.as_mut()) };
 
-    // 1. Resolve path relative to current file (or CWD if top-level)
     let current_dir = ctx.get_current_dir();
     let absolute_path = current_dir
         .join(&path)
         .canonicalize()
-        .map_err(|e| -> NixError {
+        .map_err(|e| -> NixError { format!("Failed to resolve path {}: {}", path, e).into() })?;
-            format!("Failed to resolve path {}: {}", path, e).into()
-        })?;
 
-    // 2. Psh to stack for nested imports (RAII guard ensures pop on drop)
     let mut guard = PathDropGuard::new(absolute_path.clone(), ctx);
     let ctx = guard.as_ctx();
 
-    // 3. Read file
     let content = std::fs::read_to_string(&absolute_path).map_err(|e| -> NixError {
         format!("Failed to read {}: {}", absolute_path.display(), e).into()
     })?;
 
-    // 4. Parse
     let root = rnix::Root::parse(&content);
     if !root.errors().is_empty() {
         return Err(format!(
@@ -106,18 +97,17 @@ fn op_import(state: &mut OpState, #[string] path: String) -> std::result::Result
         .into());
     }
 
-    // 5. Downgrade to IR
     let expr = root
         .tree()
         .expr()
         .ok_or_else(|| -> NixError { "No expression in file".to_string().into() })?;
     let expr_id = ctx
+        .as_mut()
         .downgrade_ctx()
         .downgrade(expr)
         .map_err(|e| -> NixError { format!("Downgrade error: {}", e).into() })?;
 
-    // 6. Codegen - returns JS code string
+    Ok(ctx.get_ir(expr_id).compile(Pin::get_ref(ctx.as_ref())))
-    Ok(ctx.get_ir(expr_id).compile(ctx))
 }
 
 #[deno_core::op2]
@@ -134,8 +124,11 @@ fn op_path_exists(#[string] path: String) -> bool {
 
 #[deno_core::op2]
 #[string]
-fn op_resolve_path(state: &mut OpState, #[string] path: String) -> std::result::Result<String, NixError> {
+fn op_resolve_path(
-    let ptr = state.borrow::<RefCell<NonNull<Context>>>().borrow();
+    state: &mut OpState,
+    #[string] path: String,
+) -> std::result::Result<String, NixError> {
+    let ptr = state.borrow::<RefCell<NonNull<Ctx>>>().borrow();
     let ctx = unsafe { ptr.as_ref() };
 
     // If already absolute, return as-is
@@ -206,7 +199,7 @@ impl<'a, 'b> RuntimeCtx<'a, 'b> {
     }
 }
 
-pub fn new_js_runtime(ctx: &mut Context) -> JsRuntime {
+pub fn new_js_runtime(ctx: NonNull<Ctx>) -> JsRuntime {
     // Initialize V8 once
     static INIT: Once = Once::new();
     INIT.call_once(|| {
@@ -223,9 +216,7 @@ pub fn new_js_runtime(ctx: &mut Context) -> JsRuntime {
 }
 
 // Main entry point
-pub fn run(script: String, ctx: &mut Context) -> Result<Value> {
+pub fn run(script: String, runtime: &mut JsRuntime) -> Result<Value> {
-    let mut runtime = new_js_runtime(ctx);
-
     // Execute user script
     let global_value = runtime
         .execute_script("<eval>", script)
@@ -322,10 +313,7 @@ fn is_thunk<'a, 'b>(val: v8::Local<'a, v8::Value>, ctx: &RuntimeCtx<'a, 'b>) ->
 }
 
 /// Check if a function is a primop
-fn primop_name<'a, 'b>(
+fn primop_name<'a, 'b>(val: v8::Local<'a, v8::Value>, ctx: &RuntimeCtx<'a, 'b>) -> Option<String> {
-    val: v8::Local<'a, v8::Value>,
-    ctx: &RuntimeCtx<'a, 'b>,
-) -> Option<String> {
     if !val.is_function() {
         return None;
     }
@@ -373,8 +361,13 @@ fn primop_app_name<'a, 'b>(
     }
 }
 
-#[test]
+#[cfg(test)]
-fn to_value_working() {
+mod test {
+    use super::*;
+    use crate::context::Context;
+
+    #[test]
+    fn to_value_working() {
         let mut ctx = Context::new();
         assert_eq!(
             run(
@@ -382,7 +375,7 @@ fn to_value_working() {
                   test: [1., 9223372036854775807n, true, false, 'hello world!']
                 })"
                 .into(),
-            &mut ctx
+                &mut ctx.js_runtime
             )
             .unwrap(),
             Value::AttrSet(AttrSet::new(std::collections::BTreeMap::from([(
@@ -396,4 +389,5 @@ fn to_value_working() {
                 ]))
             )])))
         );
+    }
 }