elvish/pkg/cli/tty.go
Qi Xiao 7a72b6346a Reorganize pkg/sys into portable and non-portable system utilities.
Non-portable ones are moved into new packages pkg/sys/e{unix windows}. The "e"
prefix is needed to avoid conflict with packages under golang.org/x/sys/ and can
mean "extra".
2021-10-02 13:14:00 +01:00

120 lines
2.7 KiB
Go

package cli
import (
"fmt"
"os"
"os/signal"
"sync"
"src.elv.sh/pkg/cli/term"
"src.elv.sh/pkg/sys"
)
// TTY is the type the terminal dependency of the editor needs to satisfy.
type TTY interface {
// Setup sets up the terminal for the CLI app.
//
// This method returns a restore function that undoes the setup, and any
// error during setup. It only returns fatal errors that make the terminal
// unsuitable for later operations; non-fatal errors may be reported by
// showing a warning message, but not returned.
//
// This method should be called before any other method is called.
Setup() (restore func(), err error)
// ReadEvent reads a terminal event.
ReadEvent() (term.Event, error)
// SetRawInput requests the next n ReadEvent calls to read raw events. It
// is applicable to environments where events are represented as a special
// sequences, such as VT100. It is a no-op if events are delivered as whole
// units by the terminal, such as Windows consoles.
SetRawInput(n int)
// CloseReader releases resources allocated for reading terminal events.
CloseReader()
term.Writer
// NotifySignals start relaying signals and returns a channel on which
// signals are delivered.
NotifySignals() <-chan os.Signal
// StopSignals stops the relaying of signals. After this function returns,
// the channel returned by NotifySignals will no longer deliver signals.
StopSignals()
// Size returns the height and width of the terminal.
Size() (h, w int)
}
type aTTY struct {
in, out *os.File
r term.Reader
term.Writer
sigCh chan os.Signal
rawMutex sync.Mutex
raw int
}
// NewTTY returns a new TTY from input and output terminal files.
func NewTTY(in, out *os.File) TTY {
return &aTTY{in: in, out: out, Writer: term.NewWriter(out)}
}
func (t *aTTY) Setup() (func(), error) {
restore, err := term.Setup(t.in, t.out)
return func() {
err := restore()
if err != nil {
fmt.Println(t.out, "failed to restore terminal properties:", err)
}
}, err
}
func (t *aTTY) Size() (h, w int) {
return sys.WinSize(t.out)
}
func (t *aTTY) ReadEvent() (term.Event, error) {
if t.r == nil {
t.r = term.NewReader(t.in)
}
if t.consumeRaw() {
return t.r.ReadRawEvent()
}
return t.r.ReadEvent()
}
func (t *aTTY) consumeRaw() bool {
t.rawMutex.Lock()
defer t.rawMutex.Unlock()
if t.raw <= 0 {
return false
}
t.raw--
return true
}
func (t *aTTY) SetRawInput(n int) {
t.rawMutex.Lock()
defer t.rawMutex.Unlock()
t.raw = n
}
func (t *aTTY) CloseReader() {
if t.r != nil {
t.r.Close()
}
t.r = nil
}
func (t *aTTY) NotifySignals() <-chan os.Signal {
t.sigCh = sys.NotifySignals()
return t.sigCh
}
func (t *aTTY) StopSignals() {
signal.Stop(t.sigCh)
close(t.sigCh)
t.sigCh = nil
}