package mountinfo

import (
	"os"
)

// 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)
}

// Mounted determines if a specified path is a mount point. In case of any
// error, false (and an error) is returned.
//
// If a non-existent path is specified, an appropriate error is returned.
// In case the caller is not interested in this particular error, it should
// be handled separately using e.g. errors.Is(err, fs.ErrNotExist).
func Mounted(path string) (bool, error) {
	// root is always mounted
	if path == string(os.PathSeparator) {
		return true, nil
	}
	return mounted(path)
}

// 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 is the ID of the parent mount (or of self for the root
	// of this mount namespace's mount tree).
	Parent int

	// Major and Minor are the major and the minor components of the Dev
	// field of unix.Stat_t structure returned by unix.*Stat calls for
	// files on this filesystem.
	Major, Minor int

	// Root is the pathname of the directory in the filesystem which forms
	// the root of this mount.
	Root string

	// Mountpoint is the pathname of the mount point relative to the
	// process's root directory.
	Mountpoint string

	// Options is a comma-separated list of mount options.
	Options string

	// Optional are zero or more fields of the form "tag[:value]",
	// separated by a space.  Currently, the possible optional fields are
	// "shared", "master", "propagate_from", and "unbindable". For more
	// information, see mount_namespaces(7) Linux man page.
	Optional string

	// FSType is the filesystem type in the form "type[.subtype]".
	FSType string

	// Source is filesystem-specific information, or "none".
	Source string

	// VFSOptions is a comma-separated list of superblock options.
	VFSOptions string
}