Struct ChildManager 

pub struct ChildManager {
    children: Vec<Child>,
    shut_down: bool,
}

Manages child processes spawned by snarkos commands, ensuring they can be gracefully terminated and reaped.

• On Unix, we rely on setsid() at spawn + sending signals to the process group via kill(-pid, SIGTERM|SIGKILL) so helpers die too.
• On Windows, we rely on a Job Object (created/managed elsewhere) to ensure the tree is contained and hard-killed as a backstop; we still explicitly terminate lingering children during shutdown.

Fields

children: Vec<Child>

All direct snarkos children. Invariant: a Child is inserted exactly once and removed never.

shut_down: bool

Ensures shutdown is idempotent even if called multiple times (explicit + Drop).

Implementations

impl ChildManager

pub fn new() -> Self

Create an empty manager.

pub fn push(&mut self, child: Child)

Register a freshly–spawned child so it can be reaped later.

pub fn shutdown_all(&mut self, timeout: Duration)

Graceful-then-forceful termination sequence (idempotent):

1. Polite: ask everyone to exit.
   • Unix: send SIGTERM to the process group of each child via kill(-pid, SIGTERM).
   • Windows: no-op by default — rely on app-level handling and Job Objects.
2. Wait up to timeout for children to exit (polling try_wait).
3. Hard kill survivors:
   • Unix: kill(-pid, SIGKILL).
   • Windows: Child::kill() (TerminateProcess). Job Object is a safety net.
4. Reap: call wait() on all children to avoid zombies (ignore errors).

Trait Implementations

impl Drop for ChildManager

fn drop(&mut self)

Executes the destructor for this type.