keepawake

keepawake is a native-only MoonBit module that exposes a small, readable API for keeping a machine awake while long-running work is in progress.

This first iteration focuses on a minimal public surface that is easy to maintain and easy to extend:

• acquire returns a guard that starts the native keep-awake request.
• Guard::release ends the request and is safe to call more than once.
• with_keepawake wraps scoped work and releases automatically.
• Scope keeps the policy choice explicit without exposing backend details.

Install

Add the module to your project, then import justjavac/keepawake.

moon add justjavac/keepawake

Package configuration:

import {
  "justjavac/keepawake",
}

API Overview

let guard = @keepawake.acquire(
  reason="Rendering a long animation",
  scope=@keepawake.Scope::PreventSystemAndDisplaySleep,
)

// ... perform the long-running work ...

guard.release()

Use the scoped helper when you want automatic cleanup:

let result = @keepawake.with_keepawake(
  () => {
    // ... perform the long-running work ...
    "done"
  },
  reason="Syncing a large local cache",
  scope=@keepawake.Scope::PreventSystemSleep,
)

Platform Notes

Windows

The Windows backend uses SetThreadExecutionState, which is the standard API for declaring thread-level execution requirements.

macOS

The macOS backend creates IOKit power assertions. The implementation loads the required frameworks dynamically so the package does not need platform-specific linker flags for this minimal version.

Linux

The Linux backend uses systemd-inhibit as the smallest maintainable cross-distribution starting point for this first version.

• PreventSystemSleep maps to sleep
• PreventDisplaySleep maps to idle
• PreventSystemAndDisplaySleep maps to idle:sleep

In headless or non-systemd environments the module may raise BackendUnavailable with a descriptive message instead of pretending the request succeeded.

Examples

Run the example module from the repository root:

moon -C examples run basic

The example acquires a guard, keeps the machine awake for roughly five seconds, and then releases it.

License

MIT