source: code/trunk/vendor/github.com/mattn/go-isatty/isatty_windows.go@ 824

//go:build windows && !appengine
// +build windows,!appengine

package isatty

import (
        "errors"
        "strings"
        "syscall"
        "unicode/utf16"
        "unsafe"
)

const (
        objectNameInfo uintptr = 1
        fileNameInfo           = 2
        fileTypePipe           = 3
)

var (
        kernel32                         = syscall.NewLazyDLL("kernel32.dll")
        ntdll                            = syscall.NewLazyDLL("ntdll.dll")
        procGetConsoleMode               = kernel32.NewProc("GetConsoleMode")
        procGetFileInformationByHandleEx = kernel32.NewProc("GetFileInformationByHandleEx")
        procGetFileType                  = kernel32.NewProc("GetFileType")
        procNtQueryObject                = ntdll.NewProc("NtQueryObject")
)

func init() {
        // Check if GetFileInformationByHandleEx is available.
        if procGetFileInformationByHandleEx.Find() != nil {
                procGetFileInformationByHandleEx = nil
        }
}

// IsTerminal return true if the file descriptor is terminal.
func IsTerminal(fd uintptr) bool {
        var st uint32
        r, _, e := syscall.Syscall(procGetConsoleMode.Addr(), 2, fd, uintptr(unsafe.Pointer(&st)), 0)
        return r != 0 && e == 0
}

// Check pipe name is used for cygwin/msys2 pty.
// Cygwin/MSYS2 PTY has a name like:
//   \{cygwin,msys}-XXXXXXXXXXXXXXXX-ptyN-{from,to}-master
func isCygwinPipeName(name string) bool {
        token := strings.Split(name, "-")
        if len(token) < 5 {
                return false
        }

        if token[0] != `\msys` &&
                token[0] != `\cygwin` &&
                token[0] != `\Device\NamedPipe\msys` &&
                token[0] != `\Device\NamedPipe\cygwin` {
                return false
        }

        if token[1] == "" {
                return false
        }

        if !strings.HasPrefix(token[2], "pty") {
                return false
        }

        if token[3] != `from` && token[3] != `to` {
                return false
        }

        if token[4] != "master" {
                return false
        }

        return true
}

// getFileNameByHandle use the undocomented ntdll NtQueryObject to get file full name from file handler
// since GetFileInformationByHandleEx is not available under windows Vista and still some old fashion
// guys are using Windows XP, this is a workaround for those guys, it will also work on system from
// Windows vista to 10
// see https://stackoverflow.com/a/18792477 for details
func getFileNameByHandle(fd uintptr) (string, error) {
        if procNtQueryObject == nil {
                return "", errors.New("ntdll.dll: NtQueryObject not supported")
        }

        var buf [4 + syscall.MAX_PATH]uint16
        var result int
        r, _, e := syscall.Syscall6(procNtQueryObject.Addr(), 5,
                fd, objectNameInfo, uintptr(unsafe.Pointer(&buf)), uintptr(2*len(buf)), uintptr(unsafe.Pointer(&result)), 0)
        if r != 0 {
                return "", e
        }
        return string(utf16.Decode(buf[4 : 4+buf[0]/2])), nil
}

// IsCygwinTerminal() return true if the file descriptor is a cygwin or msys2
// terminal.
func IsCygwinTerminal(fd uintptr) bool {
        if procGetFileInformationByHandleEx == nil {
                name, err := getFileNameByHandle(fd)
                if err != nil {
                        return false
                }
                return isCygwinPipeName(name)
        }

        // Cygwin/msys's pty is a pipe.
        ft, _, e := syscall.Syscall(procGetFileType.Addr(), 1, fd, 0, 0)
        if ft != fileTypePipe || e != 0 {
                return false
        }

        var buf [2 + syscall.MAX_PATH]uint16
        r, _, e := syscall.Syscall6(procGetFileInformationByHandleEx.Addr(),
                4, fd, fileNameInfo, uintptr(unsafe.Pointer(&buf)),
                uintptr(len(buf)*2), 0, 0)
        if r == 0 || e != 0 {
                return false
        }

        l := *(*uint32)(unsafe.Pointer(&buf))
        return isCygwinPipeName(string(utf16.Decode(buf[2 : 2+l/2])))
}