73 lines
1.2 KiB
Go
73 lines
1.2 KiB
Go
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package main
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import (
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"fmt"
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"io"
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"log"
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"os/exec"
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"strings"
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)
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// Pajen represents an instance of the pajen.pl script running in infinite
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// generation mode.
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type Pajen struct {
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Chan chan string
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proc *exec.Cmd
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out io.ReadCloser
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}
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// NewPajen starts the pajen script at the path given.
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func NewPajen(path string) (*Pajen, error) {
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p := new(Pajen)
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p.proc = exec.Command("/usr/bin/perl", path, "-i")
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p.proc.Stdin = p
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pi, err := p.proc.StdoutPipe()
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if err != nil {
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return nil, fmt.Errorf("pajen: pipe pajen.pl: %w", err)
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}
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p.out = pi
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p.proc.Stderr = p.proc.Stdout
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p.Chan = make(chan string)
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if err := p.proc.Start(); err != nil {
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return nil, fmt.Errorf("pajen: start pajen.pl: %w", err)
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}
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go p.run()
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return p, nil
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}
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// Read feeds constant newlines to the program.
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func (r *Pajen) Read(b []byte) (int, error) {
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if len(b) < 1 {
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return 0, nil
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}
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return copy(b, []byte("\n")), nil
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}
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func (r *Pajen) run() {
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buf := make([]byte, 255)
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for {
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_, err := r.out.Read(buf)
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if err != nil {
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log.Println("pajen read error:", err)
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return
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}
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wk := string(buf)
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lines := strings.Split(wk, "\n")
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for _, l := range lines {
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if l != "" && l != "\n" {
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r.Chan <- l
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}
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}
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}
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}
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