Caption support (#2462)

Co-authored-by: WithoutPants <53250216+WithoutPants@users.noreply.github.com>

vendor/github.com/asticode/go-astikit/exec.go

@@ -0,0 +1,104 @@
+package astikit
+
+import (
+	"context"
+	"fmt"
+	"os/exec"
+	"strings"
+	"sync"
+)
+
+// Statuses
+const (
+	ExecStatusCrashed = "crashed"
+	ExecStatusRunning = "running"
+	ExecStatusStopped = "stopped"
+)
+
+// ExecHandler represents an object capable of handling the execution of a cmd
+type ExecHandler struct {
+	cancel  context.CancelFunc
+	ctx     context.Context
+	err     error
+	o       sync.Once
+	stopped bool
+}
+
+// Status returns the cmd status
+func (h *ExecHandler) Status() string {
+	if h.ctx.Err() != nil {
+		if h.stopped || h.err == nil {
+			return ExecStatusStopped
+		}
+		return ExecStatusCrashed
+	}
+	return ExecStatusRunning
+}
+
+// Stop stops the cmd
+func (h *ExecHandler) Stop() {
+	h.o.Do(func() {
+		h.cancel()
+		h.stopped = true
+	})
+}
+
+// ExecCmdOptions represents exec options
+type ExecCmdOptions struct {
+	Args       []string
+	CmdAdapter func(cmd *exec.Cmd, h *ExecHandler) error
+	Name       string
+	StopFunc   func(cmd *exec.Cmd) error
+}
+
+// ExecCmd executes a cmd
+// The process will be stopped when the worker stops
+func ExecCmd(w *Worker, o ExecCmdOptions) (h *ExecHandler, err error) {
+	// Create handler
+	h = &ExecHandler{}
+	h.ctx, h.cancel = context.WithCancel(w.Context())
+
+	// Create command
+	cmd := exec.Command(o.Name, o.Args...)
+
+	// Adapt command
+	if o.CmdAdapter != nil {
+		if err = o.CmdAdapter(cmd, h); err != nil {
+			err = fmt.Errorf("astikit: adapting cmd failed: %w", err)
+			return
+		}
+	}
+
+	// Start
+	w.Logger().Infof("astikit: starting %s", strings.Join(cmd.Args, " "))
+	if err = cmd.Start(); err != nil {
+		err = fmt.Errorf("astikit: executing %s: %w", strings.Join(cmd.Args, " "), err)
+		return
+	}
+
+	// Handle context
+	go func() {
+		// Wait for context to be done
+		<-h.ctx.Done()
+
+		// Get stop func
+		f := func() error { return cmd.Process.Kill() }
+		if o.StopFunc != nil {
+			f = func() error { return o.StopFunc(cmd) }
+		}
+
+		// Stop
+		if err = f(); err != nil {
+			w.Logger().Error(fmt.Errorf("astikit: stopping cmd failed: %w", err))
+			return
+		}
+	}()
+
+	// Execute in a task
+	w.NewTask().Do(func() {
+		h.err = cmd.Wait()
+		h.cancel()
+		w.Logger().Infof("astikit: status is now %s for %s", h.Status(), strings.Join(cmd.Args, " "))
+	})
+	return
+}