Naveen Sampath | 04696f7 | 2022-06-13 15:19:14 +0530 | [diff] [blame] | 1 | // +build windows |
| 2 | |
| 3 | package flags |
| 4 | |
| 5 | import ( |
| 6 | "syscall" |
| 7 | "unsafe" |
| 8 | ) |
| 9 | |
| 10 | type ( |
| 11 | SHORT int16 |
| 12 | WORD uint16 |
| 13 | |
| 14 | SMALL_RECT struct { |
| 15 | Left SHORT |
| 16 | Top SHORT |
| 17 | Right SHORT |
| 18 | Bottom SHORT |
| 19 | } |
| 20 | |
| 21 | COORD struct { |
| 22 | X SHORT |
| 23 | Y SHORT |
| 24 | } |
| 25 | |
| 26 | CONSOLE_SCREEN_BUFFER_INFO struct { |
| 27 | Size COORD |
| 28 | CursorPosition COORD |
| 29 | Attributes WORD |
| 30 | Window SMALL_RECT |
| 31 | MaximumWindowSize COORD |
| 32 | } |
| 33 | ) |
| 34 | |
| 35 | var kernel32DLL = syscall.NewLazyDLL("kernel32.dll") |
| 36 | var getConsoleScreenBufferInfoProc = kernel32DLL.NewProc("GetConsoleScreenBufferInfo") |
| 37 | |
| 38 | func getError(r1, r2 uintptr, lastErr error) error { |
| 39 | // If the function fails, the return value is zero. |
| 40 | if r1 == 0 { |
| 41 | if lastErr != nil { |
| 42 | return lastErr |
| 43 | } |
| 44 | return syscall.EINVAL |
| 45 | } |
| 46 | return nil |
| 47 | } |
| 48 | |
| 49 | func getStdHandle(stdhandle int) (uintptr, error) { |
| 50 | handle, err := syscall.GetStdHandle(stdhandle) |
| 51 | if err != nil { |
| 52 | return 0, err |
| 53 | } |
| 54 | return uintptr(handle), nil |
| 55 | } |
| 56 | |
| 57 | // GetConsoleScreenBufferInfo retrieves information about the specified console screen buffer. |
| 58 | // http://msdn.microsoft.com/en-us/library/windows/desktop/ms683171(v=vs.85).aspx |
| 59 | func GetConsoleScreenBufferInfo(handle uintptr) (*CONSOLE_SCREEN_BUFFER_INFO, error) { |
| 60 | var info CONSOLE_SCREEN_BUFFER_INFO |
| 61 | if err := getError(getConsoleScreenBufferInfoProc.Call(handle, uintptr(unsafe.Pointer(&info)), 0)); err != nil { |
| 62 | return nil, err |
| 63 | } |
| 64 | return &info, nil |
| 65 | } |
| 66 | |
| 67 | func getTerminalColumns() int { |
| 68 | defaultWidth := 80 |
| 69 | |
| 70 | stdoutHandle, err := getStdHandle(syscall.STD_OUTPUT_HANDLE) |
| 71 | if err != nil { |
| 72 | return defaultWidth |
| 73 | } |
| 74 | |
| 75 | info, err := GetConsoleScreenBufferInfo(stdoutHandle) |
| 76 | if err != nil { |
| 77 | return defaultWidth |
| 78 | } |
| 79 | |
| 80 | if info.MaximumWindowSize.X > 0 { |
| 81 | return int(info.MaximumWindowSize.X) |
| 82 | } |
| 83 | |
| 84 | return defaultWidth |
| 85 | } |