source: code/trunk/config/config.go@ 62

package config

import (
        "bufio"
        "fmt"
        "io"
        "os"
        "strings"
        "unicode"
)

type TLS struct {
        CertPath, KeyPath string
}

type Server struct {
        Addr     string
        Hostname string
        TLS      *TLS
}

func Defaults() *Server {
        hostname, err := os.Hostname()
        if err != nil {
                hostname = "localhost"
        }
        return &Server{
                Addr:     ":6667",
                Hostname: hostname,
        }
}

func Load(path string) (*Server, error) {
        f, err := os.Open(path)
        if err != nil {
                return nil, err
        }
        defer f.Close()

        return Parse(f)
}

func Parse(r io.Reader) (*Server, error) {
        p := parser{br: bufio.NewReader(r)}
        directives, err := p.file()
        if err != nil {
                return nil, fmt.Errorf("failed to parse config file: %v", err)
        }

        srv := Defaults()
        for _, d := range directives {
                switch d.Name {
                case "listen":
                        if err := d.parseParams(&srv.Addr); err != nil {
                                return nil, err
                        }
                case "hostname":
                        if err := d.parseParams(&srv.Hostname); err != nil {
                                return nil, err
                        }
                case "tls":
                        tls := &TLS{}
                        if err := d.parseParams(&tls.CertPath, &tls.KeyPath); err != nil {
                                return nil, err
                        }
                        srv.TLS = tls
                default:
                        return nil, fmt.Errorf("unknown directive %q", d.Name)
                }
        }

        return srv, nil
}

type directive struct {
        Name   string
        Params []string
}

func (d *directive) parseParams(out ...*string) error {
        if len(d.Params) != len(out) {
                return fmt.Errorf("directive %q has wrong number of parameters: expected %v, got %v", d.Name, len(out), len(d.Params))
        }
        for i := range out {
                *out[i] = d.Params[i]
        }
        return nil
}

type parser struct {
        br *bufio.Reader
}

func (p *parser) skipSpace() error {
        for {
                r, _, err := p.br.ReadRune()
                if err == io.EOF {
                        break
                } else if err != nil {
                        return err
                }
                if !unicode.IsSpace(r) || r == '\n' {
                        p.br.UnreadRune()
                        break
                }
        }
        return nil
}

func (p *parser) atom() (string, error) {
        var sb strings.Builder
        for {
                r, _, err := p.br.ReadRune()
                if err == io.EOF && sb.Len() > 0 {
                        break
                } else if err != nil {
                        return "", err
                }
                if unicode.IsSpace(r) {
                        p.br.UnreadRune()
                        if err := p.skipSpace(); err != nil {
                                return "", err
                        }
                        break
                }
                sb.WriteRune(r)
        }
        return sb.String(), nil
}

func (p *parser) directive() (*directive, error) {
        name, err := p.atom()
        if err == io.EOF {
                return nil, io.EOF
        } else if err != nil {
                return nil, fmt.Errorf("failed to read directive name: %v", err)
        }

        var params []string
        for {
                r, _, err := p.br.ReadRune()
                if err == io.EOF {
                        break
                } else if err != nil {
                        return nil, err
                }
                if r == '\n' {
                        break
                }
                p.br.UnreadRune()

                param, err := p.atom()
                if err == io.EOF {
                        break
                } else if err != nil {
                        return nil, fmt.Errorf("failed to read directive param: %v", err)
                }
                params = append(params, param)
        }

        return &directive{name, params}, nil
}

func (p *parser) file() ([]directive, error) {
        var l []directive
        for {
                d, err := p.directive()
                if err == io.EOF {
                        break
                } else if err != nil {
                        return nil, err
                }
                l = append(l, *d)
        }
        return l, nil
}