1// Copyright 2014 The gocui Authors. All rights reserved.
 2// Use of this source code is governed by a BSD-style
 3// license that can be found in the LICENSE file.
 4
 5// +build !windows
 6
 7package gocui
 8
 9import (
10	"os"
11	"os/signal"
12	"syscall"
13	"unsafe"
14
15	"github.com/go-errors/errors"
16)
17
18// getTermWindowSize is get terminal window size on linux or unix.
19// When gocui run inside the docker contaienr need to check and get the window size.
20func (g *Gui) getTermWindowSize() (int, int, error) {
21	var sz struct {
22		rows uint16
23		cols uint16
24		_    [2]uint16 // to match underlying syscall; see https://github.com/awesome-gocui/gocui/issues/33
25	}
26
27	var termw, termh int
28
29	out, err := os.OpenFile("/dev/tty", os.O_RDWR, 0)
30	if err != nil {
31		return 0, 0, err
32	}
33	defer out.Close()
34
35	signalCh := make(chan os.Signal, 1)
36	signal.Notify(signalCh, syscall.SIGWINCH, syscall.SIGINT)
37
38	for {
39		_, _, _ = syscall.Syscall(syscall.SYS_IOCTL,
40			out.Fd(), uintptr(syscall.TIOCGWINSZ), uintptr(unsafe.Pointer(&sz)))
41
42		// check terminal window size
43		termw, termh = int(sz.cols), int(sz.rows)
44		if termw > 0 && termh > 0 {
45			return termw, termh, nil
46		}
47
48		select {
49		case signal := <-signalCh:
50			switch signal {
51			// when the terminal window size is changed
52			case syscall.SIGWINCH:
53				continue
54			// ctrl + c to cancel
55			case syscall.SIGINT:
56				return 0, 0, errors.New("stop to get term window size")
57			}
58		}
59	}
60}