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Refactor event polling code.
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This centralizes much of the logic (hopefully reducing duplication)
for polling events and the queue.  This will make it easier to make
further design changes to express a better, simpler, API to consumers.

While here addressed missing logic to handle Fini correctly on Windows.
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@gdamore
gdamore committed Dec 8, 2023
1 parent e3a99dd commit 8041b8e
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Showing 5 changed files with 158 additions and 222 deletions.
96 changes: 33 additions & 63 deletions console_win.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -33,7 +33,6 @@ type cScreen struct {
out syscall.Handle
cancelflag syscall.Handle
scandone chan struct{}
evch chan Event
quit chan struct{}
curx int
cury int
Expand All @@ -53,11 +52,11 @@ type cScreen struct {
oomode uint32
cells CellBuffer

finiOnce sync.Once

mouseEnabled bool
wg sync.WaitGroup
eventQ chan Event
stopQ chan struct{}
finiOnce sync.Once

sync.Mutex
}
Expand Down Expand Up @@ -146,7 +145,7 @@ const (
vtSgr0 = "\x1b[0m"
vtBold = "\x1b[1m"
vtUnderline = "\x1b[4m"
vtBlink = "\x1b[5m" // Not sure this is processed
vtBlink = "\x1b[5m" // Not sure if this is processed
vtReverse = "\x1b[7m"
vtSetFg = "\x1b[38;5;%dm"
vtSetBg = "\x1b[48;5;%dm"
Expand Down Expand Up @@ -179,7 +178,7 @@ func NewConsoleScreen() (Screen, error) {
}

func (s *cScreen) Init() error {
s.evch = make(chan Event, 10)
s.eventQ = make(chan Event, 10)
s.quit = make(chan struct{})
s.scandone = make(chan struct{})

Expand Down Expand Up @@ -286,7 +285,10 @@ func (s *cScreen) EnableFocus() {}
func (s *cScreen) DisableFocus() {}

func (s *cScreen) Fini() {
s.disengage()
s.finiOnce.Do(func() {
close(s.quit)
s.disengage()
})
}

func (s *cScreen) disengage() {
Expand Down Expand Up @@ -356,52 +358,6 @@ func (s *cScreen) engage() error {
return nil
}

func (s *cScreen) PostEventWait(ev Event) {
s.evch <- ev
}

func (s *cScreen) PostEvent(ev Event) error {
select {
case s.evch <- ev:
return nil
default:
return ErrEventQFull
}
}

func (s *cScreen) ChannelEvents(ch chan<- Event, quit <-chan struct{}) {
defer close(ch)
for {
select {
case <-quit:
return
case <-s.stopQ:
return
case ev := <-s.evch:
select {
case <-quit:
return
case <-s.stopQ:
return
case ch <- ev:
}
}
}
}

func (s *cScreen) PollEvent() Event {
select {
case <-s.stopQ:
return nil
case ev := <-s.evch:
return ev
}
}

func (s *cScreen) HasPendingEvent() bool {
return len(s.evch) > 0
}

type cursorInfo struct {
size uint32
visible uint32
Expand Down Expand Up @@ -701,6 +657,13 @@ func mrec2btns(mbtns, flags uint32) ButtonMask {
return btns
}

func (s *cScreen) postEvent(ev Event) {
select {
case s.eventQ <- ev:
case <-s.quit:
}
}

func (s *cScreen) getConsoleInput() error {
// cancelFlag comes first as WaitForMultipleObjects returns the lowest index
// in the event that both events are signalled.
Expand Down Expand Up @@ -743,19 +706,17 @@ func (s *cScreen) getConsoleInput() error {
krec.mod = getu32(rec.data[12:])

if krec.isdown == 0 || krec.repeat < 1 {
// its a key release event, ignore it
// it's a key release event, ignore it
return nil
}
if krec.ch != 0 {
// synthesized key code
for krec.repeat > 0 {
// convert shift+tab to backtab
if mod2mask(krec.mod) == ModShift && krec.ch == vkTab {
s.PostEventWait(NewEventKey(KeyBacktab, 0,
ModNone))
s.postEvent(NewEventKey(KeyBacktab, 0, ModNone))
} else {
s.PostEventWait(NewEventKey(KeyRune, rune(krec.ch),
mod2mask(krec.mod)))
s.postEvent(NewEventKey(KeyRune, rune(krec.ch), mod2mask(krec.mod)))
}
krec.repeat--
}
Expand All @@ -767,8 +728,7 @@ func (s *cScreen) getConsoleInput() error {
return nil
}
for krec.repeat > 0 {
s.PostEventWait(NewEventKey(key, rune(krec.ch),
mod2mask(krec.mod)))
s.postEvent(NewEventKey(key, rune(krec.ch), mod2mask(krec.mod)))
krec.repeat--
}

Expand All @@ -781,14 +741,13 @@ func (s *cScreen) getConsoleInput() error {
mrec.flags = getu32(rec.data[12:])
btns := mrec2btns(mrec.btns, mrec.flags)
// we ignore double click, events are delivered normally
s.PostEventWait(NewEventMouse(int(mrec.x), int(mrec.y), btns,
mod2mask(mrec.mod)))
s.postEvent(NewEventMouse(int(mrec.x), int(mrec.y), btns, mod2mask(mrec.mod)))

case resizeEvent:
var rrec resizeRecord
rrec.x = geti16(rec.data[0:])
rrec.y = geti16(rec.data[2:])
s.PostEventWait(NewEventResize(int(rrec.x), int(rrec.y)))
s.postEvent(NewEventResize(int(rrec.x), int(rrec.y)))

default:
}
Expand Down Expand Up @@ -1128,7 +1087,10 @@ func (s *cScreen) resize() {
uintptr(s.out),
uintptr(1),
uintptr(unsafe.Pointer(&r)))
_ = s.PostEvent(NewEventResize(w, h))
select {
case s.eventQ <- NewEventResize(w, h):
default:
}
}

func (s *cScreen) clearScreen(style Style, vtEnable bool) {
Expand Down Expand Up @@ -1298,3 +1260,11 @@ func (s *cScreen) Tty() (Tty, bool) {
func (s *cScreen) GetCells() *CellBuffer {
return &s.cells
}

func (s *cScreen) EventQ() chan Event {
return s.eventQ
}

func (s *cScreen) StopQ() <-chan struct{} {
return s.stopQ
}
65 changes: 59 additions & 6 deletions screen.go
View file
Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
// Copyright 2022 The TCell Authors
// Copyright 2023 The TCell Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use file except in compliance with the License.
Expand Down Expand Up @@ -314,11 +314,6 @@ type screenImpl interface {
HideCursor()
SetCursorStyle(CursorStyle)
Size() (width, height int)
ChannelEvents(ch chan<- Event, quit <-chan struct{})
PollEvent() Event
HasPendingEvent() bool
PostEvent(ev Event) error
PostEventWait(ev Event)
EnableMouse(...MouseFlags)
DisableMouse()
EnablePaste()
Expand Down Expand Up @@ -351,6 +346,15 @@ type screenImpl interface {
// GetCells returns a pointer to the underlying CellBuffer that the implementation uses.
// Various methods will write to these for performance, but will use the lock to do so.
GetCells() *CellBuffer

// StopQ is closed when the screen is shut down via Fini. It remains open if the screen
// is merely suspended.
StopQ() <-chan struct{}

// EventQ delivers events. Events are posted to this by the screen in response to
// key presses, resizes, etc. Application code receives events from this via the
// Screen.PollEvent, Screen.ChannelEvents APIs.
EventQ() chan Event
}

type baseScreen struct {
Expand Down Expand Up @@ -417,3 +421,52 @@ func (b *baseScreen) LockRegion(x, y, width, height int, lock bool) {
}
b.Unlock()
}

func (b *baseScreen) ChannelEvents(ch chan<- Event, quit <-chan struct{}) {
defer close(ch)
for {
select {
case <-quit:
return
case <-b.StopQ():
return
case ev := <-b.EventQ():
select {
case <-quit:
return
case <-b.StopQ():
return
case ch <- ev:
}
}
}
}

func (b *baseScreen) PollEvent() Event {
select {
case <-b.StopQ():
return nil
case ev := <-b.EventQ():
return ev
}
}

func (b *baseScreen) HasPendingEvent() bool {
return len(b.EventQ()) > 0
}

func (b *baseScreen) PostEventWait(ev Event) {
select {
case b.EventQ() <- ev:
case <-b.StopQ():
}
}

func (b *baseScreen) PostEvent(ev Event) error {
select {
case b.EventQ() <- ev:
return nil
default:
return ErrEventQFull
}
}
63 changes: 16 additions & 47 deletions simulation.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -309,68 +309,29 @@ func (s *simscreen) resize() {
if w != ow || h != oh {
s.back.Resize(w, h)
ev := NewEventResize(w, h)
s.PostEvent(ev)
s.postEvent(ev)
}
}

func (s *simscreen) Colors() int {
return 256
}

func (s *simscreen) ChannelEvents(ch chan<- Event, quit <-chan struct{}) {
defer close(ch)
for {
select {
case <-quit:
return
case <-s.quit:
return
case ev := <-s.evch:
select {
case <-quit:
return
case <-s.quit:
return
case ch <- ev:
}
}
}
}

func (s *simscreen) PollEvent() Event {
select {
case <-s.quit:
return nil
case ev := <-s.evch:
return ev
}
}

func (s *simscreen) HasPendingEvent() bool {
return len(s.evch) > 0
}

func (s *simscreen) PostEventWait(ev Event) {
s.evch <- ev
}

func (s *simscreen) PostEvent(ev Event) error {
func (s *simscreen) postEvent(ev Event) {
select {
case s.evch <- ev:
return nil
default:
return ErrEventQFull
case <-s.quit:
}
}

func (s *simscreen) InjectMouse(x, y int, buttons ButtonMask, mod ModMask) {
ev := NewEventMouse(x, y, buttons, mod)
s.PostEvent(ev)
s.postEvent(ev)
}

func (s *simscreen) InjectKey(key Key, r rune, mod ModMask) {
ev := NewEventKey(key, r, mod)
s.PostEvent(ev)
s.postEvent(ev)
}

func (s *simscreen) InjectKeyBytes(b []byte) bool {
Expand All @@ -381,7 +342,7 @@ outer:
if b[0] >= ' ' && b[0] <= 0x7F {
// printable ASCII easy to deal with -- no encodings
ev := NewEventKey(KeyRune, rune(b[0]), ModNone)
s.PostEvent(ev)
s.postEvent(ev)
b = b[1:]
continue
}
Expand All @@ -393,7 +354,7 @@ outer:
mod = ModCtrl
}
ev := NewEventKey(Key(b[0]), 0, mod)
s.PostEvent(ev)
s.postEvent(ev)
b = b[1:]
continue
}
Expand All @@ -407,7 +368,7 @@ outer:
r, _ := utf8.DecodeRune(utfb[:nout])
if r != utf8.RuneError {
ev := NewEventKey(KeyRune, r, ModNone)
s.PostEvent(ev)
s.postEvent(ev)
}
b = b[nin:]
continue outer
Expand Down Expand Up @@ -526,3 +487,11 @@ func (s *simscreen) Tty() (Tty, bool) {
func (s *simscreen) GetCells() *CellBuffer {
return &s.back
}

func (s *simscreen) EventQ() chan Event {
return s.evch
}

func (s *simscreen) StopQ() <-chan struct{} {
return s.quit
}
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