omxplayer_helpers.go

package omxplayer

import (
	"fmt"
	"io/ioutil"
	"os"
	"strings"
	"time"

	log "github.com/sirupsen/logrus"
)

// removeFile removes the specified file. Errors are ignored.
func removeFile(path string) {
	log.WithFields(log.Fields{
		"path": path,
	}).Debug("omxplayer: removing file")
	os.Remove(path)
}

// waitForFile waits for the specified file to exist before returning. If the an
// error, other than the file not existing, occurs, the error is returned. If,
// after 100 attempts, the file does not exist, an error is returned.
func waitForFile(path string) error {
	log.WithFields(log.Fields{
		"file": path,
	}).Debug("omxplayer: waiting for file")
	for i := 0; i < 100; i++ {
		_, err := os.Stat(path)
		if err == nil || !os.IsNotExist(err) {
			return err
		}
		time.Sleep(50 * time.Millisecond)
	}
	return fmt.Errorf("omxplayer: file does not exist: %s", path)
}

// readFile waits for the specified file to contain contents, and then returns
// those contents as a string. If an error occurs while reading the file, the
// error is returned. If the file has no content after 100 attempts, an error is
// returned.
func readFile(path string) (string, error) {
	log.WithFields(log.Fields{
		"file": path,
	}).Debug("omxplayer: reading file")
	for i := 0; i < 100; i++ {
		bytes, err := ioutil.ReadFile(path)
		if err != nil {
			return "", err
		}
		if len(bytes) > 0 {
			return strings.TrimSpace(string(bytes)), err
		}
		time.Sleep(50 * time.Millisecond)
	}
	return "", fmt.Errorf("omxplayer: file is empty: %s", path)
}

// setEnv sets the specified environment variable to the specified value.
func setEnv(variable, value string) {
	log.WithFields(log.Fields{
		"variable": variable,
		"value":    value,
	}).Debug("omxplayer: setting environment variable")
	os.Setenv(variable, value)
}