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package hostsfile
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import (
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"fmt"
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"net"
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"sort"
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"strings"
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)
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// HostsLine represents a line of the hosts file after being parsed into their respective parts
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type HostsLine struct {
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IP string // IP found at the beginning of the line
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Hosts []string // Hosts split into a slice on the space char
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Comment string // Contents of everything after the comment char in the line
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Raw string // Raw contents of the line as parsed in or updated after changes
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Err error // Used for error checking during parsing
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}
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const commentChar string = "#"
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// NewHostsLine takes a raw line as a string and parses it into a new instance of HostsLine e.g. "192.168.1.1 host1 host2 # comments"
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func NewHostsLine(raw string) HostsLine {
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output := HostsLine{Raw: raw}
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if output.HasComment() { //trailing comment
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commentSplit := strings.Split(output.Raw, commentChar)
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raw = commentSplit[0]
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output.Comment = commentSplit[1]
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}
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if output.IsComment() { //whole line is comment
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return output
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}
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fields := strings.Fields(raw)
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if len(fields) == 0 {
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return output
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}
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rawIP := fields[0]
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if net.ParseIP(rawIP) == nil {
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output.Err = fmt.Errorf("bad hosts line: %q", raw)
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}
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output.IP = rawIP
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output.Hosts = fields[1:]
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return output
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}
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// String to make HostsLine a fmt.Stringer
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func (l *HostsLine) String() string {
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return l.ToRaw()
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}
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// ToRaw returns the HostsLine's contents as a raw string
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func (l *HostsLine) ToRaw() string {
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var comment string
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if l.IsComment() { //Whole line is comment
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return l.Raw
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}
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if l.Comment != "" {
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comment = fmt.Sprintf(" %s%s", commentChar, l.Comment)
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}
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return fmt.Sprintf("%s %s%s", l.IP, strings.Join(l.Hosts, " "), comment)
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}
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// RemoveDuplicateHosts checks all hosts in a line and removes duplicates
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func (l *HostsLine) RemoveDuplicateHosts() {
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unique := make(map[string]struct{})
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hosts := make([]string, len(l.Hosts))
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copy(hosts, l.Hosts)
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l.Hosts = []string{}
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for _, host := range hosts {
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if _, ok := unique[host]; !ok {
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unique[host] = struct{}{}
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l.Hosts = append(l.Hosts, host)
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}
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}
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l.RegenRaw()
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}
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// Deprecated: will be made internal, combines the hosts and comments of two lines together,
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func (l *HostsLine) Combine(hostline HostsLine) {
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l.combine(hostline)
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}
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func (l *HostsLine) combine(hostline HostsLine) {
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l.Hosts = append(l.Hosts, hostline.Hosts...)
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if l.Comment == "" {
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l.Comment = hostline.Comment
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} else {
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l.Comment = fmt.Sprintf("%s %s", l.Comment, hostline.Comment)
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}
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l.RegenRaw()
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}
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func (l *HostsLine) SortHosts() {
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sort.Strings(l.Hosts)
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l.RegenRaw()
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}
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func (l *HostsLine) IsComment() bool {
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return strings.HasPrefix(strings.TrimSpace(l.Raw), commentChar)
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}
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func (l *HostsLine) HasComment() bool {
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return strings.Contains(l.Raw, commentChar)
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}
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func (l *HostsLine) IsValid() bool {
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return l.IP != ""
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}
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func (l *HostsLine) IsMalformed() bool {
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return l.Err != nil
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}
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func (l *HostsLine) RegenRaw() {
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l.Raw = l.ToRaw()
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}
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