package mountinfo

import "io"

// GetMounts retrieves a list of mounts for the current running process,
// with an optional filter applied (use nil for no filter).
func GetMounts(f FilterFunc) ([]*Info, error) {
	return parseMountTable(f)
}

// GetMountsFromReader retrieves a list of mounts from the
// reader provided, with an optional filter applied (use nil
// for no filter). This can be useful in tests or benchmarks
// that provide a fake mountinfo data.
func GetMountsFromReader(reader io.Reader, f FilterFunc) ([]*Info, error) {
	return parseInfoFile(reader, f)
}

// Mounted determines if a specified mountpoint has been mounted.
// On Linux it looks at /proc/self/mountinfo.
func Mounted(mountpoint string) (bool, error) {
	entries, err := GetMounts(SingleEntryFilter(mountpoint))
	if err != nil {
		return false, err
	}

	return len(entries) > 0, nil
}

// Info reveals information about a particular mounted filesystem. This
// struct is populated from the content in the /proc/<pid>/mountinfo file.
type Info struct {
	// ID is a unique identifier of the mount (may be reused after umount).
	ID int

	// Parent indicates the ID of the mount parent (or of self for the top of the
	// mount tree).
	Parent int

	// Major indicates one half of the device ID which identifies the device class.
	Major int

	// Minor indicates one half of the device ID which identifies a specific
	// instance of device.
	Minor int

	// Root of the mount within the filesystem.
	Root string

	// Mountpoint indicates the mount point relative to the process's root.
	Mountpoint string

	// Opts represents mount-specific options.
	Opts string

	// Optional represents optional fields.
	Optional string

	// Fstype indicates the type of filesystem, such as EXT3.
	Fstype string

	// Source indicates filesystem specific information or "none".
	Source string

	// VfsOpts represents per super block options.
	VfsOpts string
}