lookup: remove legacy lookup code

Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>

lookup.go

@@ -1,5 +1,3 @@
-// +build go1.7
-
 package mtree
 
 import (

lookup_old.go

@@ -1,102 +0,0 @@
-// +build !go1.7
-
-package mtree
-
-import (
-	"bufio"
-	"bytes"
-	"io"
-	"os"
-	"strconv"
-	"strings"
-)
-
-const groupFile = "/etc/group"
-
-var colon = []byte{':'}
-
-// Group represents a grouping of users.
-//
-// On POSIX systems Gid contains a decimal number representing the group ID.
-type Group struct {
-	Gid  string // group ID
-	Name string // group name
-}
-
-func lookupGroupID(id string) (*Group, error) {
-	f, err := os.Open(groupFile)
-	if err != nil {
-		return nil, err
-	}
-	defer f.Close()
-	return findGroupID(id, f)
-}
-
-func findGroupID(id string, r io.Reader) (*Group, error) {
-	if v, err := readColonFile(r, matchGroupIndexValue(id, 2)); err != nil {
-		return nil, err
-	} else if v != nil {
-		return v.(*Group), nil
-	}
-	return nil, UnknownGroupIDError(id)
-}
-
-// lineFunc returns a value, an error, or (nil, nil) to skip the row.
-type lineFunc func(line []byte) (v interface{}, err error)
-
-// readColonFile parses r as an /etc/group or /etc/passwd style file, running
-// fn for each row. readColonFile returns a value, an error, or (nil, nil) if
-// the end of the file is reached without a match.
-func readColonFile(r io.Reader, fn lineFunc) (v interface{}, err error) {
-	bs := bufio.NewScanner(r)
-	for bs.Scan() {
-		line := bs.Bytes()
-		// There's no spec for /etc/passwd or /etc/group, but we try to follow
-		// the same rules as the glibc parser, which allows comments and blank
-		// space at the beginning of a line.
-		line = bytes.TrimSpace(line)
-		if len(line) == 0 || line[0] == '#' {
-			continue
-		}
-		v, err = fn(line)
-		if v != nil || err != nil {
-			return
-		}
-	}
-	return nil, bs.Err()
-}
-
-func matchGroupIndexValue(value string, idx int) lineFunc {
-	var leadColon string
-	if idx > 0 {
-		leadColon = ":"
-	}
-	substr := []byte(leadColon + value + ":")
-	return func(line []byte) (v interface{}, err error) {
-		if !bytes.Contains(line, substr) || bytes.Count(line, colon) < 3 {
-			return
-		}
-		// wheel:*:0:root
-		parts := strings.SplitN(string(line), ":", 4)
-		if len(parts) < 4 || parts[0] == "" || parts[idx] != value ||
-			// If the file contains +foo and you search for "foo", glibc
-			// returns an "invalid argument" error. Similarly, if you search
-			// for a gid for a row where the group name starts with "+" or "-",
-			// glibc fails to find the record.
-			parts[0][0] == '+' || parts[0][0] == '-' {
-			return
-		}
-		if _, err := strconv.Atoi(parts[2]); err != nil {
-			return nil, nil
-		}
-		return &Group{Name: parts[0], Gid: parts[2]}, nil
-	}
-}
-
-// UnknownGroupIDError is returned by LookupGroupId when
-// a group cannot be found.
-type UnknownGroupIDError string
-
-func (e UnknownGroupIDError) Error() string {
-	return "group: unknown groupid " + string(e)
-}