Core preferences service

createPreferencesService({file}) from arcane-os/core/preferences supplies the existing Arcane.preferences RPC methods to a native Core host. The default export is the same factory. Construction performs no filesystem work. The application selects its writable file and owns preference names, defaults and schemas; this service does not invent them or alter operating-system settings.

import path from 'node:path';
import {createPreferencesService} from 'arcane-os/core/preferences';

export default function createMoonPreferences(options, context) {
    return createPreferencesService({
        file: path.join(context.stateRoot, 'moon-preferences.json')
    });
}

Select this application-owned factory through native.services, and include it in package.nativeResources. Supply the application's selected stateRoot through the explicit launch configuration. See native packaging.

Storage remains {schemaVersion:1,entries}. Exact keys, complete JSON values and additional existing document metadata are retained. A missing file starts with empty entries; reading it does not create a file. Unreadable or malformed files report their real errors and are not replaced with an empty record. Values that JSON cannot represent completely fail before replacement. There is no migration, truncation, namespace rewrite, default injection or frozen result.

Operations selecting the same resolved filename share one ordered queue within the Core process. This is not a cross-process file lock. Writes flush their new content and replace the selected file before acknowledgment. Filesystem failures remain observable, including cleanup errors; this is not a claim of survival across every hardware or operating-system failure.

set, setMany and delete use lifetime:'service': renderer cancellation does not discard accepted writes. drain() and dispose() stop acceptance and wait for accepted operations; later calls reject with CORE_CLOSING. Read operations observe their request cancellation. Use the existing Core host shutdown owner so saved preferences finish before the native process exits.