Function scan_sandboxes

crates/openshell-server/src/grpc/provider.rs:319–348

Iterate over every `Sandbox` in the store and collect items produced by `f`. `f` receives each decoded sandbox; returning `Some(T)` includes the value in the output, `None` skips it. This is the shared pagination kernel used by all sandbox-scan helpers.

(store: &Store, mut f: F)

///
/// This is the shared pagination kernel used by all sandbox-scan helpers.
async fn scan_sandboxes<T, F>(store: &Store, mut f: F) -> Result<Vec<T>, Status>
where
    F: FnMut(Sandbox) -> Option<T>,
{
    let mut out = Vec::new();
    let mut offset = 0u32;
    loop {
        let records = store
            .list(Sandbox::object_type(), 1000, offset)
            .await
            .map_err(|e| Status::internal(format!("list sandboxes failed: {e}")))?;
        if records.is_empty() {
            break;
        }
        offset = offset
            .checked_add(
                u32::try_from(records.len())
                    .map_err(|_| Status::internal("sandbox page size exceeded u32"))?,
            )
            .ok_or_else(|| Status::internal("sandbox pagination offset overflow"))?;
        for record in records {
            let sandbox = Sandbox::decode(record.payload.as_slice())
                .map_err(|e| Status::internal(format!("decode sandbox failed: {e}")))?;
            if let Some(item) = f(sandbox) {
                out.push(item);
            }
        }
    }
    Ok(out)
}

async fn sandboxes_using_provider(
    store: &Store,