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package diodes
import (
"context"
"time"
)
// Diode is any implementation of a diode.
type Diode interface {
Set(GenericDataType)
TryNext() (GenericDataType, bool)
}
// Poller will poll a diode until a value is available.
type Poller struct {
Diode
interval time.Duration
ctx context.Context
}
// PollerConfigOption can be used to setup the poller.
type PollerConfigOption func(*Poller)
// WithPollingInterval sets the interval at which the diode is queried
// for new data. The default is 10ms.
func WithPollingInterval(interval time.Duration) PollerConfigOption {
return func(c *Poller) {
c.interval = interval
}
}
// WithPollingContext sets the context to cancel any retrieval (Next()). It
// will not change any results for adding data (Set()). Default is
// context.Background().
func WithPollingContext(ctx context.Context) PollerConfigOption {
return func(c *Poller) {
c.ctx = ctx
}
}
// NewPoller returns a new Poller that wraps the given diode.
func NewPoller(d Diode, opts ...PollerConfigOption) *Poller {
p := &Poller{
Diode: d,
interval: 10 * time.Millisecond,
ctx: context.Background(),
}
for _, o := range opts {
o(p)
}
return p
}
// Next polls the diode until data is available or until the context is done.
// If the context is done, then nil will be returned.
func (p *Poller) Next() GenericDataType {
for {
data, ok := p.Diode.TryNext()
if !ok {
if p.isDone() {
return nil
}
time.Sleep(p.interval)
continue
}
return data
}
}
func (p *Poller) isDone() bool {
select {
case <-p.ctx.Done():
return true
default:
return false
}
}
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