// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package user

import 

// Current returns the current user.
//
// The first call will cache the current user information.
// Subsequent calls will return the cached value and will not reflect
// changes to the current user.
func () (*User, error) {
	cache.Do(func() { cache.u, cache.err = current() })
	if cache.err != nil {
		return nil, cache.err
	}
	 := *cache.u // copy
	return &, nil
}

// cache of the current user
var cache struct {
	sync.Once
	u   *User
	err error
}

// Lookup looks up a user by username. If the user cannot be found, the
// returned error is of type UnknownUserError.
func ( string) (*User, error) {
	if ,  := Current();  == nil && .Username ==  {
		return , 
	}
	return lookupUser()
}

// LookupId looks up a user by userid. If the user cannot be found, the
// returned error is of type UnknownUserIdError.
func ( string) (*User, error) {
	if ,  := Current();  == nil && .Uid ==  {
		return , 
	}
	return lookupUserId()
}

// LookupGroup looks up a group by name. If the group cannot be found, the
// returned error is of type UnknownGroupError.
func ( string) (*Group, error) {
	return lookupGroup()
}

// LookupGroupId looks up a group by groupid. If the group cannot be found, the
// returned error is of type UnknownGroupIdError.
func ( string) (*Group, error) {
	return lookupGroupId()
}

// GroupIds returns the list of group IDs that the user is a member of.
func ( *User) () ([]string, error) {
	return listGroups()
}