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//! Optional rpc-backed eval path for the `nms` REPL.
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//!
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//! Activated by `nms --rpc-user <UUID>`. Routes user forms through an
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//! `rpc::Session` instead of the in-process `nms::interpreter`, so the
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//! same code path the sshd subsystem will drive becomes available as a
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//! local debug REPL. Without `--rpc-user`, `nms` stays a pure language
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//! sandbox — the rpc dep just sits unused.
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//!
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//! Each user input is auto-wrapped in a fresh `(:id N :form <form>)`
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//! envelope before handoff; the response prints verbatim (the rpc envelope
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//! shape is terse enough to read directly).
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use std::sync::atomic::{AtomicU64, Ordering};

            

        

            

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use anyhow::{Context, Result};

            

        

            

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use rpc::{ScriptCtx, Session};

            

        

            

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use tokio::runtime::{Builder, Runtime};

            

        

            

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use uuid::Uuid;

            

        

            

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pub struct RpcEval {

            

        

            

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    session: Session,

            

        

            

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    runtime: Runtime,

            

        

            

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    counter: AtomicU64,

            

        

            

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}

            

        

            

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impl RpcEval {

            

        

            

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    /// Builds an rpc-backed eval surface for `user_id`. Verifies a

            

        

            

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    /// `DATABASE_URL` is set up-front so a missing-env footgun surfaces as

            

        

            

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    /// a startup error rather than a per-form connection panic from deep

            

        

            

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    /// inside the first DB-touching native fn.

            

        

            

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    pub fn new(user_id: Uuid) -> Result<Self> {

            

        

            

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        if std::env::var("DATABASE_URL").is_err() {

            

        

            

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            anyhow::bail!(

            

        

            

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                "rpc-mode requires DATABASE_URL to be set so server::command::* \

            

        

            

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                 can reach Postgres; export it (or drop --rpc-user for the \

            

        

            

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                 sandbox-only REPL)"

            

        

            

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            );

            

        

            

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        }

            

        

            

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        let runtime = Builder::new_current_thread()

            

        

            

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            .enable_all()

            

        

            

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            .build()

            

        

            

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            .context("rpc-mode tokio runtime build failed")?;

            

        

            

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        let session = Session::new(ScriptCtx::new(user_id))

            

        

            

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            .map_err(|err| anyhow::anyhow!("rpc::Session::new failed: {err:?}"))?;

            

        

            

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        Ok(Self {

            

        

            

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            session,

            

        

            

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            runtime,

            

        

            

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            counter: AtomicU64::new(1),

            

        

            

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        })

            

        

            

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    }

            

        

            

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    /// Wraps `form_text` in a fresh envelope, runs it through the Session,

            

        

            

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    /// and returns the wire response. Multi-form input (whitespace-

            

        

            

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    /// separated top-level forms) is dispatched as one envelope per form

            

        

            

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    /// in source order; responses are joined by newline.

            

        

            

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    pub fn eval(&mut self, form_text: &str) -> String {

            

        

            

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        let trimmed = form_text.trim();

            

        

            

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        if trimmed.is_empty() {

            

        

            

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            return String::new();

            

        

            

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        }

            

        

            

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        let id = self.counter.fetch_add(1, Ordering::Relaxed);

            

        

            

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        // Closing paren on its own line so a trailing line-comment in the

            

        

            

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        // form can't comment out the envelope terminator (which would make

            

        

            

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        // `handle_form` reject an unbalanced request).

            

        

            

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        let envelope = format!("(:id {id} :form {trimmed}\n)");

            

        

            

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        self.runtime.block_on(self.session.handle_form(&envelope))

            

        

            

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    }

            

        

            

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}