packer-cn/common/terminal_windows.go

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// +build windows
package common
import (
"syscall"
"unsafe"
)
// windows constants and structures pulled from msdn
const (
_STD_INPUT_HANDLE = -10
_STD_OUTPUT_HANDLE = -11
_STD_ERROR_HANDLE = -12
)
type (
_SHORT int16
_WORD uint16
_SMALL_RECT struct {
Left, Top, Right, Bottom _SHORT
}
_COORD struct {
X, Y _SHORT
}
_CONSOLE_SCREEN_BUFFER_INFO struct {
dwSize, dwCursorPosition _COORD
wAttributes _WORD
srWindow _SMALL_RECT
dwMaximumWindowSize _COORD
}
)
// Low-level functions that call into Windows API for getting console info
var kernel32 = syscall.NewLazyDLL("kernel32.dll")
var kernel32_GetStdHandleProc = kernel32.NewProc("GetStdHandle")
var kernel32_GetConsoleScreenBufferInfoProc = kernel32.NewProc("GetConsoleScreenBufferInfo")
func kernel32_GetStdHandle(nStdHandle int32) (syscall.Handle, error) {
res, _, err := kernel32_GetStdHandleProc.Call(uintptr(nStdHandle))
if res == uintptr(syscall.InvalidHandle) {
return syscall.InvalidHandle, error(err)
}
return syscall.Handle(res), nil
}
func kernel32_GetConsoleScreenBufferInfo(hConsoleOutput syscall.Handle, info *_CONSOLE_SCREEN_BUFFER_INFO) error {
ok, _, err := kernel32_GetConsoleScreenBufferInfoProc.Call(uintptr(hConsoleOutput), uintptr(unsafe.Pointer(info)))
if int(ok) == 0 {
return error(err)
}
return nil
}
// windows api to get the console screen buffer info
func getConsoleScreenBufferInfo(csbi *_CONSOLE_SCREEN_BUFFER_INFO) (err error) {
var (
bi _CONSOLE_SCREEN_BUFFER_INFO
fd syscall.Handle
)
// Re-open CONOUT$ as in some instances, stdout may be closed and guaranteed an stdout
if fd, err = syscall.Open("CONOUT$", syscall.O_RDWR, 0); err != nil {
return err
}
defer syscall.Close(fd)
// grab the dimensions for the console
if err = kernel32_GetConsoleScreenBufferInfo(fd, &bi); err != nil {
return err
}
*csbi = bi
return nil
}
func platformGetTerminalDimensions() (width, height int, err error) {
var csbi _CONSOLE_SCREEN_BUFFER_INFO
if err = getConsoleScreenBufferInfo(&csbi); err != nil {
return 0, 0, err
}
return int(csbi.dwSize.X), int(csbi.dwSize.Y), nil
}