// Package privatefile handles bounded private files. Runtime support is Linux
// only; other platforms refuse operations until their privacy guarantees exist.
package privatefile

import "errors"

var ErrUnavailable = errors.New("private file unavailable")
var ErrUnsupported = errors.New("private files unsupported on this platform")

// Read returns exact bytes from an owned, single-link, regular 0600 file.
// Paths must be absolute and already clean. It rejects symlinks in every path component. The caller validates payload
// syntax and completeness: Read cannot distinguish an interrupted write from
// intentionally short content. max must be positive.
func Read(path string, max int) ([]byte, error) { return read(path, max) }

// CreateExclusiveDurable creates a new 0600 file and checks file and parent
// synchronization before returning success. The parent must already exist and
// be owned and private. The path must be absolute and already clean. Failures preserve any created file, which prevents
// retry from overwriting it. The caller must retain its recovery material and
// must not treat a later Read as proof that this operation completed. A future
// resume caller needs its own checked durability barrier after validating the
// saved payload; reopening a file does not repair a failed synchronization.
func CreateExclusiveDurable(path string, data []byte, max int) error {
	return create(path, data, max)
}