packer-cn/helper/wrappedstreams/streams.go

50 lines
1.1 KiB
Go

// STOLEN SHAMELESSLY FROM THE TERRAFORM REPO BECAUSE VENDORING OUT
// WRAPPEDREADLINE AND WRAPPEDSTREAMS FELT LIKE TOO MUCH WORK.
//
// "a little copying is better than a lot of dependency"
//
// Package wrappedstreams provides access to the standard OS streams
// (stdin, stdout, stderr) even if wrapped under panicwrap.
package wrappedstreams
import (
"os"
"github.com/mitchellh/panicwrap"
)
// Stdin returns the true stdin of the process.
func Stdin() *os.File {
stdin, _, _ := fds()
return stdin
}
// Stdout returns the true stdout of the process.
func Stdout() *os.File {
_, stdout, _ := fds()
return stdout
}
// Stderr returns the true stderr of the process.
func Stderr() *os.File {
_, _, stderr := fds()
return stderr
}
func fds() (stdin, stdout, stderr *os.File) {
stdin, stdout, stderr = os.Stdin, os.Stdout, os.Stderr
if panicwrap.Wrapped(nil) {
initPlatform()
stdin, stdout, stderr = wrappedStdin, wrappedStdout, wrappedStderr
}
return
}
// These are the wrapped standard streams. These are setup by the
// platform specific code in initPlatform.
var (
wrappedStdin *os.File
wrappedStdout *os.File
wrappedStderr *os.File
)