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arikawa/utils/wsutil/heart.go

116 lines
2.4 KiB
Go

package wsutil
import (
"context"
"time"
"github.com/pkg/errors"
"github.com/diamondburned/arikawa/internal/heart"
"github.com/diamondburned/arikawa/internal/moreatomic"
)
// TODO API
type EventLoopHandler interface {
EventHandler
HeartbeatCtx(context.Context) error
}
// PacemakerLoop provides an event loop with a pacemaker. A zero-value instance
// is a valid instance only when RunAsync is called first.
type PacemakerLoop struct {
pacemaker *heart.Pacemaker // let's not copy this
pacedeath chan error
running moreatomic.Bool
events <-chan Event
handler func(*OP) error
Extras ExtraHandlers
ErrorLog func(error)
}
func (p *PacemakerLoop) errorLog(err error) {
if p.ErrorLog == nil {
WSDebug("Uncaught error:", err)
return
}
p.ErrorLog(err)
}
// Pace calls the pacemaker's Pace function.
func (p *PacemakerLoop) Pace(ctx context.Context) error {
return p.pacemaker.Pace(ctx)
}
// Echo calls the pacemaker's Echo function.
func (p *PacemakerLoop) Echo() {
p.pacemaker.Echo()
}
// Stop calls the pacemaker's Stop function.
func (p *PacemakerLoop) Stop() {
p.pacemaker.Stop()
}
func (p *PacemakerLoop) Stopped() bool {
return p == nil || !p.running.Get()
}
func (p *PacemakerLoop) RunAsync(
heartrate time.Duration, evs <-chan Event, evl EventLoopHandler, exit func(error)) {
WSDebug("Starting the pacemaker loop.")
p.pacemaker = heart.NewPacemaker(heartrate, evl.HeartbeatCtx)
p.events = evs
p.handler = evl.HandleOP
// callers should explicitly handle waitgroups.
p.pacedeath = p.pacemaker.StartAsync(nil)
p.running.Set(true)
go func() {
exit(p.startLoop())
}()
}
func (p *PacemakerLoop) startLoop() error {
defer WSDebug("Pacemaker loop has exited.")
defer p.running.Set(false)
for {
select {
case err := <-p.pacedeath:
WSDebug("Pacedeath returned with error:", err)
return errors.Wrap(err, "pacemaker died, reconnecting")
case ev, ok := <-p.events:
if !ok {
WSDebug("Events channel closed, stopping pacemaker.")
defer WSDebug("Pacemaker stopped automatically.")
// Events channel is closed. Kill the pacemaker manually and
// die.
p.pacemaker.Stop()
return <-p.pacedeath
}
o, err := DecodeOP(ev)
if err != nil {
return errors.Wrap(err, "failed to decode OP")
}
// Check the events before handling.
p.Extras.Check(o)
// Handle the event
if err := p.handler(o); err != nil {
p.errorLog(errors.Wrap(err, "handler failed"))
}
}
}
}