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moby--moby/pkg/term/term.go
Daniel Nephin 4f0d95fa6e Add canonical import comment
Signed-off-by: Daniel Nephin <dnephin@docker.com>
2018-02-05 16:51:57 -05:00

124 lines
3.1 KiB
Go

// +build !windows
// Package term provides structures and helper functions to work with
// terminal (state, sizes).
package term // import "github.com/docker/docker/pkg/term"
import (
"errors"
"fmt"
"io"
"os"
"os/signal"
"golang.org/x/sys/unix"
)
var (
// ErrInvalidState is returned if the state of the terminal is invalid.
ErrInvalidState = errors.New("Invalid terminal state")
)
// State represents the state of the terminal.
type State struct {
termios Termios
}
// Winsize represents the size of the terminal window.
type Winsize struct {
Height uint16
Width uint16
x uint16
y uint16
}
// StdStreams returns the standard streams (stdin, stdout, stderr).
func StdStreams() (stdIn io.ReadCloser, stdOut, stdErr io.Writer) {
return os.Stdin, os.Stdout, os.Stderr
}
// GetFdInfo returns the file descriptor for an os.File and indicates whether the file represents a terminal.
func GetFdInfo(in interface{}) (uintptr, bool) {
var inFd uintptr
var isTerminalIn bool
if file, ok := in.(*os.File); ok {
inFd = file.Fd()
isTerminalIn = IsTerminal(inFd)
}
return inFd, isTerminalIn
}
// IsTerminal returns true if the given file descriptor is a terminal.
func IsTerminal(fd uintptr) bool {
var termios Termios
return tcget(fd, &termios) == 0
}
// RestoreTerminal restores the terminal connected to the given file descriptor
// to a previous state.
func RestoreTerminal(fd uintptr, state *State) error {
if state == nil {
return ErrInvalidState
}
if err := tcset(fd, &state.termios); err != 0 {
return err
}
return nil
}
// SaveState saves the state of the terminal connected to the given file descriptor.
func SaveState(fd uintptr) (*State, error) {
var oldState State
if err := tcget(fd, &oldState.termios); err != 0 {
return nil, err
}
return &oldState, nil
}
// DisableEcho applies the specified state to the terminal connected to the file
// descriptor, with echo disabled.
func DisableEcho(fd uintptr, state *State) error {
newState := state.termios
newState.Lflag &^= unix.ECHO
if err := tcset(fd, &newState); err != 0 {
return err
}
handleInterrupt(fd, state)
return nil
}
// SetRawTerminal puts the terminal connected to the given file descriptor into
// raw mode and returns the previous state. On UNIX, this puts both the input
// and output into raw mode. On Windows, it only puts the input into raw mode.
func SetRawTerminal(fd uintptr) (*State, error) {
oldState, err := MakeRaw(fd)
if err != nil {
return nil, err
}
handleInterrupt(fd, oldState)
return oldState, err
}
// SetRawTerminalOutput puts the output of terminal connected to the given file
// descriptor into raw mode. On UNIX, this does nothing and returns nil for the
// state. On Windows, it disables LF -> CRLF translation.
func SetRawTerminalOutput(fd uintptr) (*State, error) {
return nil, nil
}
func handleInterrupt(fd uintptr, state *State) {
sigchan := make(chan os.Signal, 1)
signal.Notify(sigchan, os.Interrupt)
go func() {
for range sigchan {
// quit cleanly and the new terminal item is on a new line
fmt.Println()
signal.Stop(sigchan)
close(sigchan)
RestoreTerminal(fd, state)
os.Exit(1)
}
}()
}