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mirror of https://gitlab.crans.org/nounous/ghostream.git synced 2024-12-23 00:22:19 +00:00
ghostream/stream/messaging.go
2020-10-18 15:13:13 +02:00

100 lines
2.0 KiB
Go

// Package stream defines a structure to communication between inputs and outputs
package stream
import (
"sync"
)
// Stream makes packages able to subscribe to an incoming stream
type Stream struct {
// Incoming data come from this channel
Broadcast chan<- []byte
// Use a map to be able to delete an item
outputs map[chan []byte]struct{}
// Count clients for statistics
nbClients int
// Mutex to lock outputs map
lock sync.Mutex
}
// New creates a new stream.
func New() *Stream {
s := &Stream{}
broadcast := make(chan []byte, 1024)
s.Broadcast = broadcast
s.outputs = make(map[chan []byte]struct{})
s.nbClients = 0
go s.run(broadcast)
return s
}
func (s *Stream) run(broadcast <-chan []byte) {
for msg := range broadcast {
s.lock.Lock()
for output := range s.outputs {
select {
case output <- msg:
default:
// If full, do a ring buffer
// Check that output is not of size zero
if len(output) > 1 {
<-output
}
}
}
s.lock.Unlock()
}
// Incoming chan has been closed, close all outputs
s.lock.Lock()
for ch := range s.outputs {
delete(s.outputs, ch)
close(ch)
}
s.lock.Unlock()
}
// Close the incoming chan, this will also delete all outputs
func (s *Stream) Close() {
close(s.Broadcast)
}
// Register a new output on a stream.
func (s *Stream) Register(output chan []byte) {
s.lock.Lock()
defer s.lock.Unlock()
s.outputs[output] = struct{}{}
}
// Unregister removes an output.
// If hidden in true, then do not count this client.
func (s *Stream) Unregister(output chan []byte) {
s.lock.Lock()
defer s.lock.Unlock()
// Make sure we did not already close this output
_, ok := s.outputs[output]
if ok {
delete(s.outputs, output)
close(output)
}
}
// ClientCount returns the number of clients
func (s *Stream) ClientCount() int {
return s.nbClients
}
// IncrementClientCount increments the number of clients
func (s *Stream) IncrementClientCount() {
s.nbClients++
}
// DecrementClientCount decrements the number of clients
func (s *Stream) DecrementClientCount() {
s.nbClients--
}