terraform/helper/wrappedreadline/wrappedreadline_unix.go

// +build darwin dragonfly freebsd linux,!appengine netbsd openbsd

package wrappedreadline

import (
	"syscall"
	"unsafe"

	"github.com/hashicorp/terraform/helper/wrappedstreams"
)

// getWidth impl for Unix
func getWidth() int {
	stdoutFd := int(wrappedstreams.Stdout().Fd())
	stderrFd := int(wrappedstreams.Stderr().Fd())

	w := getWidthFd(stdoutFd)
	if w < 0 {
		w = getWidthFd(stderrFd)
	}

	return w
}

type winsize struct {
	Row    uint16
	Col    uint16
	Xpixel uint16
	Ypixel uint16
}

// get width of the terminal
func getWidthFd(stdoutFd int) int {
	ws := &winsize{}
	retCode, _, errno := syscall.Syscall(syscall.SYS_IOCTL,
		uintptr(stdoutFd),
		uintptr(syscall.TIOCGWINSZ),
		uintptr(unsafe.Pointer(ws)))

	if int(retCode) == -1 {
		_ = errno
		return -1
	}

	return int(ws.Col)
}