localharness 0.49.0

//! The host seam: [`BashHost`] is everything the pure evaluator needs from the
//! outside world. Eval never touches a real filesystem or clock directly — it
//! goes through this trait, so the lexer/parser/eval run unchanged under
//! `cargo test` with an in-memory host and in the browser over OPFS.
//!
//! v1 builtins are FS-ONLY (read/create/search) — no value-moving / `lh-*`
//! platform commands (deferred to v2, see `design/bashlite.md`). A builtin
//! receives its already-expanded `args` plus piped `stdin`, and returns an
//! [`Output`] (stdout text + exit code). Builtins must be TOTAL: report errors
//! as a nonzero exit + stderr text, never panic.

use crate::filesystem::Filesystem;

/// The result of running one command: captured stdout/stderr text and an exit
/// code (0 = success). Mirrors the `{ exit_code, stdout, stderr }` shape the
/// `execute_script` tool returns.
#[derive(Debug, Clone, Default, PartialEq)]
pub struct Output {
    pub stdout: String,
    pub stderr: String,
    pub code: i32,
}

impl Output {
    /// A successful run with `stdout` and exit 0.
    pub fn ok(stdout: impl Into<String>) -> Self {
        Self { stdout: stdout.into(), stderr: String::new(), code: 0 }
    }
    /// A failed run: `stderr` text and exit code `code` (defaults to 1 if 0).
    pub fn err(stderr: impl Into<String>, code: i32) -> Self {
        Self { stdout: String::new(), stderr: stderr.into(), code: if code == 0 { 1 } else { code } }
    }
}

/// The capabilities bashlite eval needs from its environment.
///
/// `async_trait`-shaped to match the rest of the codebase (`?Send` on wasm) —
/// builtins read/write OPFS, which is async in the browser.
#[cfg_attr(not(target_arch = "wasm32"), async_trait::async_trait)]
#[cfg_attr(target_arch = "wasm32", async_trait::async_trait(?Send))]
pub trait BashHost {
    /// The sandbox filesystem the fs builtins operate over (OPFS in-browser,
    /// Native on the CLI, an in-memory map in tests).
    fn fs(&self) -> &dyn Filesystem;

    /// Run a builtin command by name with already-expanded `args` and piped
    /// `stdin`. The default impl dispatches the v1 fs builtins
    /// ([`crate::bashlite::builtins`]); a host may override to add commands, but
    /// v1 ships no value-moving ones.
    async fn run_builtin(&mut self, cmd: &str, args: &[String], stdin: &str) -> Output {
        crate::bashlite::builtins::dispatch(self.fs(), cmd, args, stdin).await
    }
}