ermos/hostsfile

package hostsfile

import (
    "runtime"
    "strings"
)

// Load parses the hosts file based on the current OS.
func Load() (hosts *Hosts, err error) {
    return LoadFromOS(runtime.GOOS)
}

// LoadFromOS parses the hosts file based on the given OS.
func LoadFromOS(osName string) (hosts *Hosts, err error) {
    path, err := GetSystemPathByOS(osName)
    if err != nil {
        return
    }

    return LoadFromPath(path)
}

// LoadFromPath parses the hosts file based on the given path.
func LoadFromPath(path string) (hosts *Hosts, err error) {
    var contentByte []byte
    var content string

    hosts = &Hosts{}

    contentByte, err = readFile(path)
    if err != nil {
        return
    }

    content = string(contentByte)

    hosts.path = path

main:
    for _, l := range strings.Split(content, linebreak()) {
        var hostNames []string
        var comment string

        fields := strings.Fields(l)

        if len(fields) <= 1 || strings.HasPrefix(fields[0], "#") {
            hosts.rows = append(hosts.rows, hostRow{
                raw: l,
            })
            continue
        }

        hostNames = fields[1:]
        for i, domain := range hostNames {
            if strings.HasPrefix(domain, "#") {
                if i == 0 {
                    hosts.rows = append(hosts.rows, hostRow{
                        raw: l,
                    })
                    continue main
                }

                comment = strings.TrimSpace(
                    strings.TrimPrefix(
                        strings.Join(hostNames[i:], " "),
                        "#",
                    ),
                )
                hostNames = hostNames[:i]

                break
            }
        }

        hosts.rows = append(hosts.rows, hostRow{
            host: &Host{
                address:   fields[0],
                hostNames: hostNames,
                comment:   comment,
                parent:    hosts,
            },
        })
    }

    return hosts, nil
}