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fixes #452 Lost a key event once when exiting or suspending in v2.2.1.

Browse Source 
fixes #449 Lost keyboard input after suspend on Windows 10 PowerShell
fixes #148 Make tcell usable with any io.Reader and io.Writer

This introduces a new Tty interface so that applications can supply
their own implementation.  This should facilitate work for applications
that wish to provide e.g. a webasm version of the terminal, or that need
to use different kinds of file plumbing.
This commit is contained in:
Garrett D'Amore 2021-05-15 11:19:50 -07:00
parent 8f925d8272
commit 97c0480839
8 changed files with 339 additions and 197 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
nonblock_bsd.go
View File

@ -17,7 +17,6 @@
package tcell
import (
"os"
"syscall"
"golang.org/x/sys/unix"
@ -25,26 +24,18 @@ import (
// BSD systems use TIOC style ioctls.
// nonBlocking changes VMIN to 0, and VTIME to 1. This basically ensures that
// we can wake up the input loop. We only want to do this if we are going to interrupt
// that loop. Normally we use VMIN 1 and VTIME 0, which ensures we pick up bytes when
// they come but don't spin burning cycles.
func (t *tScreen) nonBlocking(on bool) {
fd := int(os.Stdin.Fd())
// tcSetBufParams is used by the tty driver on UNIX systems to configure the
// buffering parameters (minimum character count and minimum wait time in msec.)
func tcSetBufParams(fd int, vMin uint8, vTime uint8) error {
_ = syscall.SetNonblock(fd, true)
tio, err := unix.IoctlGetTermios(fd, unix.TIOCGETA)
if err != nil {
return
return err
}
if on {
tio.Cc[unix.VMIN] = 0
tio.Cc[unix.VTIME] = 0
} else {
// block for any output
tio.Cc[unix.VTIME] = 0
tio.Cc[unix.VMIN] = 1
tio.Cc[unix.VMIN] = vMin
tio.Cc[unix.VTIME] = vTime
if err = unix.IoctlSetTermios(fd, unix.TIOCSETA, tio); err != nil {
return err
}
_ = syscall.SetNonblock(fd, on)
// We want to set this *right now*.
_ = unix.IoctlSetTermios(fd, unix.TIOCSETA, tio)
return nil
}

21
nonblock_stub.go
View File

@ -1,21 +0,0 @@
// Copyright 2021 The TCell Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use file except in compliance with the License.
// You may obtain a copy of the license at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// +build plan9 windows js
package tcell
func (t *tScreen) nonBlocking(on bool) error {
return nil
}

33
nonblock_unix.go
View File

@ -17,36 +17,23 @@
package tcell
import (
"os"
"syscall"
"golang.org/x/sys/unix"
)
// NB: We might someday wish to move Windows to this model. However,
// that would probably mean sacrificing some of the richer key reporting
// that we can obtain with the console API present on Windows.
// nonBlocking changes VMIN to 0, and VTIME to 1. This basically ensures that
// we can wake up the input loop. We only want to do this if we are going to interrupt
// that loop. Normally we use VMIN 1 and VTIME 0, which ensures we pick up bytes when
// they come but don't spin burning cycles.
func (t *tScreen) nonBlocking(on bool) {
fd := int(os.Stdin.Fd())
// tcSetBufParams is used by the tty driver on UNIX systems to configure the
// buffering parameters (minimum character count and minimum wait time in msec.)
func tcSetBufParams(fd int, vMin uint8, vTime uint8) error {
_ = syscall.SetNonblock(fd, true)
tio, err := unix.IoctlGetTermios(fd, unix.TCGETS)
if err != nil {
return
return err
}
if on {
tio.Cc[unix.VMIN] = 0
tio.Cc[unix.VTIME] = 0
} else {
// block for any output
tio.Cc[unix.VTIME] = 0
tio.Cc[unix.VMIN] = 1
tio.Cc[unix.VMIN] = vMin
tio.Cc[unix.VTIME] = vTime
if err = unix.IoctlSetTermios(fd, unix.TCSETS, tio); err != nil {
return err
}
_ = syscall.SetNonblock(fd, on)
// We want to set this *right now*.
_ = unix.IoctlSetTermios(fd, unix.TCSETS, tio)
return nil
}

104
tscreen.go
View File

@ -16,6 +16,7 @@ package tcell
import (
"bytes"
"errors"
"io"
"os"
"strconv"
@ -42,6 +43,14 @@ import (
// $COLUMNS environment variables can be set to the actual window size,
// otherwise defaults taken from the terminal database are used.
func NewTerminfoScreen() (Screen, error) {
return NewTerminfoScreenFromTty(nil)
}
// NewTerminfoScreenFromTty returns a Screen using a custom Tty implementation.
// If the passed in tty is nil, then a reasonable default (typically /dev/tty)
// is presumed, at least on UNIX hosts. (Windows hosts will typically fail this
// call altogether.)
func NewTerminfoScreenFromTty(tty Tty) (Screen, error) {
ti, e := terminfo.LookupTerminfo(os.Getenv("TERM"))
if e != nil {
ti, e = loadDynamicTerminfo(os.Getenv("TERM"))
@ -50,7 +59,7 @@ func NewTerminfoScreen() (Screen, error) {
}
terminfo.AddTerminfo(ti)
}
t := &tScreen{ti: ti}
t := &tScreen{ti: ti, tty: tty}
t.keyexist = make(map[Key]bool)
t.keycodes = make(map[string]*tKeyCode)
@ -77,12 +86,11 @@ type tKeyCode struct {
// tScreen represents a screen backed by a terminfo implementation.
type tScreen struct {
ti *terminfo.Terminfo
tty Tty
h int
w int
fini bool
cells CellBuffer
in *os.File
out *os.File
buffering bool // true if we are collecting writes to buf instead of sending directly to out
buf bytes.Buffer
curstyle Style
@ -731,7 +739,7 @@ func (t *tScreen) writeString(s string) {
if t.buffering {
_, _ = io.WriteString(&t.buf, s)
} else {
_, _ = io.WriteString(t.out, s)
_, _ = io.WriteString(t.tty, s)
}
}
@ -739,7 +747,7 @@ func (t *tScreen) TPuts(s string) {
if t.buffering {
t.ti.TPuts(&t.buf, s)
} else {
t.ti.TPuts(t.out, s)
t.ti.TPuts(t.tty, s)
}
}
@ -807,7 +815,7 @@ func (t *tScreen) draw() {
// restore the cursor
t.showCursor()
_, _ = t.buf.WriteTo(t.out)
_, _ = t.buf.WriteTo(t.tty)
}
func (t *tScreen) EnableMouse(flags ...MouseFlags) {
@ -885,7 +893,7 @@ func (t *tScreen) Size() (int, int) {
}
func (t *tScreen) resize() {
if w, h, e := t.getWinSize(); e == nil {
if w, h, e := t.tty.WindowSize(); e == nil {
if w != t.w || h != t.h {
t.cx = -1
t.cy = -1
@ -1493,7 +1501,7 @@ func (t *tScreen) inputLoop(stopQ chan struct{}) {
default:
}
chunk := make([]byte, 128)
n, e := t.in.Read(chunk)
n, e := t.tty.Read(chunk)
switch e {
case nil:
default:
@ -1575,7 +1583,6 @@ func (t *tScreen) HasKey(k Key) bool {
func (t *tScreen) Resize(int, int, int, int) {}
func (t *tScreen) Suspend() error {
t.disengage()
return nil
@ -1584,3 +1591,82 @@ func (t *tScreen) Suspend() error {
func (t *tScreen) Resume() error {
return t.engage()
}
// engage is used to place the terminal in raw mode and establish screen size, etc.
// Thing of this is as tcell "engaging" the clutch, as it's going to be driving the
// terminal interface.
func (t *tScreen) engage() error {
t.Lock()
defer t.Unlock()
if t.tty == nil {
return ErrNoScreen
}
if t.stopQ != nil {
return errors.New("already engaged")
}
if err := t.tty.Start(); err != nil {
return err
}
if w, h, err := t.tty.WindowSize(); err == nil && w != 0 && h != 0 {
t.cells.Resize(w, h)
}
stopQ := make(chan struct{})
t.stopQ = stopQ
t.enableMouse(t.mouseFlags)
t.enablePasting(t.pasteEnabled)
ti := t.ti
t.TPuts(ti.EnterCA)
t.TPuts(ti.EnterKeypad)
t.TPuts(ti.HideCursor)
t.TPuts(ti.EnableAcs)
t.TPuts(ti.Clear)
t.wg.Add(2)
go t.inputLoop(stopQ)
go t.mainLoop(stopQ)
return nil
}
// disengage is used to release the terminal back to support from the caller.
// Think of this as tcell disengaging the clutch, so that another application
// can take over the terminal interface. This restores the TTY mode that was
// present when the application was first started.
func (t *tScreen) disengage() {
t.Lock()
stopQ := t.stopQ
t.stopQ = nil
close(stopQ)
_ = t.tty.Drain()
t.Unlock()
// wait for everything to shut down
t.wg.Wait()
// shutdown the screen and disable special modes (e.g. mouse and bracketed paste)
ti := t.ti
t.cells.Resize(0, 0)
t.TPuts(ti.ShowCursor)
t.TPuts(ti.AttrOff)
t.TPuts(ti.Clear)
t.TPuts(ti.ExitCA)
t.TPuts(ti.ExitKeypad)
t.enableMouse(0)
t.enablePasting(false)
_ = t.tty.Stop()
}
// Beep emits a beep to the terminal.
func (t *tScreen) Beep() error {
t.writeString(string(byte(7)))
return nil
}
// finalize is used to at application shutdown, and restores the terminal
// to it's initial state. It should not be called more than once.
func (t *tScreen) finalize() {
t.disengage()
_ = t.tty.Close()
}

18
tscreen_stub.go
View File

@ -20,24 +20,6 @@ package tcell
// that would probably mean sacrificing some of the richer key reporting
// that we can obtain with the console API present on Windows.
func (t *tScreen) engage() error {
return ErrNoScreen
}
func (t *tScreen) disengage() {
}
func (t *tScreen) initialize() error {
return ErrNoScreen
}
func (t *tScreen) finalize() {
}
func (t *tScreen) getWinSize() (int, int, error) {
return 0, 0, ErrNoScreen
}
func (t *tScreen) Beep() error {
return ErrNoScreen
}

112
tscreen_unix.go
View File

@ -16,118 +16,16 @@
package tcell
import (
"errors"
"os"
"os/signal"
"syscall"
"golang.org/x/term"
)
// engage is used to place the terminal in raw mode and establish screen size, etc.
// Thing of this is as tcell "engaging" the clutch, as it's going to be driving the
// terminal interface.
func (t *tScreen) engage() error {
t.Lock()
defer t.Unlock()
if t.stopQ != nil {
return errors.New("already engaged")
}
if _, err := term.MakeRaw(int(t.in.Fd())); err != nil {
return err
}
if w, h, err := term.GetSize(int(t.in.Fd())); err == nil && w != 0 && h != 0 {
t.cells.Resize(w, h)
}
stopQ := make(chan struct{})
t.stopQ = stopQ
t.nonBlocking(false)
t.enableMouse(t.mouseFlags)
t.enablePasting(t.pasteEnabled)
signal.Notify(t.sigwinch, syscall.SIGWINCH)
ti := t.ti
t.TPuts(ti.EnterCA)
t.TPuts(ti.EnterKeypad)
t.TPuts(ti.HideCursor)
t.TPuts(ti.EnableAcs)
t.TPuts(ti.Clear)
t.wg.Add(2)
go t.inputLoop(stopQ)
go t.mainLoop(stopQ)
return nil
}
// disengage is used to release the terminal back to support from the caller.
// Think of this as tcell disengaging the clutch, so that another application
// can take over the terminal interface. This restores the TTY mode that was
// present when the application was first started.
func (t *tScreen) disengage() {
t.Lock()
t.nonBlocking(true)
stopQ := t.stopQ
t.stopQ = nil
close(stopQ)
t.Unlock()
// wait for everything to shut down
t.wg.Wait()
signal.Stop(t.sigwinch)
// put back normal blocking mode
t.nonBlocking(false)
// shutdown the screen and disable special modes (e.g. mouse and bracketed paste)
ti := t.ti
t.cells.Resize(0, 0)
t.TPuts(ti.ShowCursor)
t.TPuts(ti.AttrOff)
t.TPuts(ti.Clear)
t.TPuts(ti.ExitCA)
t.TPuts(ti.ExitKeypad)
t.enableMouse(0)
t.enablePasting(false)
// restore the termios that we were started with
_ = term.Restore(int(t.in.Fd()), t.saved)
}
// initialize is used at application startup, and sets up the initial values
// including file descriptors used for terminals and saving the initial state
// so that it can be restored when the application terminates.
func (t *tScreen) initialize() error {
var err error
t.out = os.Stdout
if t.in, err = os.Open("/dev/tty"); err != nil {
return err
}
t.saved, err = term.GetState(int(t.in.Fd()))
if err == nil {
return nil
if t.tty == nil {
t.tty, err = NewDevTty()
if err != nil {
return err
}
}
return nil
}
// finalize is used to at application shutdown, and restores the terminal
// to it's initial state. It should not be called more than once.
func (t *tScreen) finalize() {
t.disengage()
}
// getWinSize is called to obtain the terminal dimensions.
func (t *tScreen) getWinSize() (int, int, error) {
return term.GetSize(int(t.in.Fd()))
}
// Beep emits a beep to the terminal.
func (t *tScreen) Beep() error {
t.writeString(string(byte(7)))
return nil
}

56
tty.go Normal file
View File

@ -0,0 +1,56 @@
// Copyright 2021 The TCell Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use file except in compliance with the License.
// You may obtain a copy of the license at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package tcell
import "io"
// Tty is an abstraction of a tty (traditionally "teletype"). This allows applications to
// provide for alternate backends, as there are situations where the traditional /dev/tty
// does not work, or where more flexible handling is required. This interface is for use
// with the terminfo-style based API. It extends the io.ReadWriter API. It is reasonable
// that the implementation might choose to use different underlying files for the Reader
// and Writer sides of this API, as part of it's internal implementation.
type Tty interface {
// Start is used to activate the Tty for use. Upon return the terminal should be
// in raw mode, non-blocking, etc. The implementation should take care of saving
// any state that is required so that it may be restored when Stop is called.
Start() error
// Stop is used to stop using this Tty instance. This may be a suspend, so that other
// terminal based applications can run in the foreground. Implementations should
// restore any state collected at Start(), and return to ordinary blocking mode, etc.
// Drain is called first to drain the input. Once this is called, no more Read
// or Write calls will be made until Start is called again.
Stop() error
// Drain is called before Stop, and ensures that the reader will wake up appropriately
// if it was blocked. This workaround is required for /dev/tty on certain UNIX systems
// to ensure that Read() does not block forever. This typically arranges for the tty driver
// to send data immediately (e.g. VMIN and VTIME both set zero) and sets a deadline on input.
// Implementations may reasonably make this a no-op. There will still be control sequences
// emitted between the time this is called, and when Stop is called.
Drain() error
// NotifyResize is used register a callback when the tty thinks the dimensions have
// changed. The standard UNIX implementation links this to a handler for SIGWINCH.
// If the supplied callback is nil, then any handler should be unregistered.
NotifyResize(cb func())
// WindowSize is called to determine the terminal dimensions. This might be determined
// by an ioctl or other means.
WindowSize() (width int, height int, err error)
io.ReadWriteCloser
}

163
tty_unix.go Normal file
View File

@ -0,0 +1,163 @@
// Copyright 2021 The TCell Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use file except in compliance with the License.
// You may obtain a copy of the license at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris zos
package tcell
import (
"errors"
"fmt"
"os"
"os/signal"
"sync"
"syscall"
"time"
"golang.org/x/term"
)
// devTty is an implementation of the Tty API based upon /dev/tty.
type devTty struct {
fd int
f *os.File
of *os.File // the first open of /dev/tty
saved *term.State
sig chan os.Signal
cb func()
stopQ chan struct{}
wg sync.WaitGroup
l sync.Mutex
}
func (tty *devTty) Read(b []byte) (int, error) {
return tty.f.Read(b)
}
func (tty *devTty) Write(b []byte) (int, error) {
return tty.f.Write(b)
}
func (tty *devTty) Close() error {
return nil
}
func (tty *devTty) Start() error {
tty.l.Lock()
defer tty.l.Unlock()
// We open another copy of /dev/tty. This is a workaround for unusual behavior
// observed in macOS, apparently caused when a subshell (for example) closes our
// own tty device (when it exits for example). Getting a fresh new one seems to
// resolve the problem. (We believe this is a bug in the macOS tty driver that
// fails to account for dup() references to the same file before applying close()
// related behaviors to the tty.) We're also holding the original copy we opened
// since closing that might have deleterious effects as well. The upshot is that
// we will have up to two separate file handles open on /dev/tty. (Note that when
// using stdin/stdout instead of /dev/tty this problem is not observed.)
var err error
if tty.f, err = os.OpenFile("/dev/tty", os.O_RDWR, 0); err != nil {
return err
}
tty.fd = int(tty.of.Fd())
if !term.IsTerminal(tty.fd) {
return errors.New("device is not a terminal")
}
_ = tty.f.SetReadDeadline(time.Time{})
saved, err := term.MakeRaw(tty.fd) // also sets vMin and vTime
if err != nil {
return err
}
tty.saved = saved
tty.stopQ = make(chan struct{})
tty.wg.Add(1)
go func(stopQ chan struct{}) {
defer tty.wg.Done()
for {
select {
case <-tty.sig:
tty.l.Lock()
cb := tty.cb
tty.l.Unlock()
cb()
case <-stopQ:
return
}
}
}(tty.stopQ)
signal.Notify(tty.sig, syscall.SIGWINCH)
return nil
}
func (tty *devTty) Drain() error {
_ = tty.f.SetReadDeadline(time.Now())
if err := tcSetBufParams(tty.fd, 0, 0); err != nil {
return err
}
return nil
}
func (tty *devTty) Stop() error {
tty.l.Lock()
if err := term.Restore(tty.fd, tty.saved); err != nil {
tty.l.Unlock()
return err
}
_ = tty.f.SetReadDeadline(time.Now())
signal.Stop(tty.sig)
close(tty.stopQ)
tty.l.Unlock()
tty.wg.Wait()
// close our tty device -- we'll get another one if we Start again later.
_ = tty.f.Close()
return nil
}
func (tty *devTty) WindowSize() (int, int, error) {
return term.GetSize(tty.fd)
}
func (tty *devTty) NotifyResize(cb func()) {
tty.l.Lock()
tty.cb = cb
tty.l.Unlock()
}
func NewDevTty() (Tty, error) {
tty := &devTty{
sig: make(chan os.Signal),
}
var err error
if tty.of, err = os.OpenFile("/dev/tty", os.O_RDWR, 0); err != nil {
return nil, err
}
tty.fd = int(tty.of.Fd())
if !term.IsTerminal(tty.fd) {
_ = tty.f.Close()
return nil, errors.New("not a terminal")
}
if tty.saved, err = term.GetState(tty.fd); err != nil {
_ = tty.f.Close()
return nil, fmt.Errorf("failed to get state: %w", err)
}
return tty, nil
}