refactor capture with broadcast.

server/internal/capture/streamsink.go

@@ -0,0 +1,193 @@
+package capture
+
+import (
+	"errors"
+	"sync"
+
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
+
+	"m1k1o/neko/internal/capture/gst"
+	"m1k1o/neko/internal/types"
+	"m1k1o/neko/internal/types/codec"
+)
+
+var moveSinkListenerMu = sync.Mutex{}
+
+type StreamSinkManagerCtx struct {
+	logger zerolog.Logger
+	mu     sync.Mutex
+	wg     sync.WaitGroup
+
+	codec      codec.RTPCodec
+	pipeline   *gst.Pipeline
+	pipelineMu sync.Mutex
+	pipelineFn func() (*gst.Pipeline, error)
+
+	listeners   int
+	listenersMu sync.Mutex
+
+	sampleFn func(sample types.Sample)
+}
+
+func streamSinkNew(codec codec.RTPCodec, pipelineFn func() (*gst.Pipeline, error), video_id string) *StreamSinkManagerCtx {
+	logger := log.With().
+		Str("module", "capture").
+		Str("submodule", "stream-sink").
+		Str("video_id", video_id).Logger()
+
+	manager := &StreamSinkManagerCtx{
+		logger:     logger,
+		codec:      codec,
+		pipelineFn: pipelineFn,
+	}
+
+	return manager
+}
+
+func (manager *StreamSinkManagerCtx) shutdown() {
+	manager.logger.Info().Msgf("shutdown")
+
+	manager.destroyPipeline()
+	manager.wg.Wait()
+}
+
+func (manager *StreamSinkManagerCtx) OnSample(listener func(sample types.Sample)) {
+	manager.sampleFn = listener
+}
+
+func (manager *StreamSinkManagerCtx) Codec() codec.RTPCodec {
+	return manager.codec
+}
+
+func (manager *StreamSinkManagerCtx) start() error {
+	if manager.listeners == 0 {
+		err := manager.createPipeline()
+		if err != nil && !errors.Is(err, types.ErrCapturePipelineAlreadyExists) {
+			return err
+		}
+
+		manager.logger.Info().Msgf("first listener, starting")
+	}
+
+	return nil
+}
+
+func (manager *StreamSinkManagerCtx) stop() {
+	if manager.listeners == 0 {
+		manager.destroyPipeline()
+		manager.logger.Info().Msgf("last listener, stopping")
+	}
+}
+
+func (manager *StreamSinkManagerCtx) addListener() {
+	manager.listenersMu.Lock()
+	manager.listeners++
+	manager.listenersMu.Unlock()
+}
+
+func (manager *StreamSinkManagerCtx) removeListener() {
+	manager.listenersMu.Lock()
+	manager.listeners--
+	manager.listenersMu.Unlock()
+}
+
+func (manager *StreamSinkManagerCtx) AddListener() error {
+	manager.mu.Lock()
+	defer manager.mu.Unlock()
+
+	// start if stopped
+	if err := manager.start(); err != nil {
+		return err
+	}
+
+	// add listener
+	manager.addListener()
+
+	return nil
+}
+
+func (manager *StreamSinkManagerCtx) RemoveListener() error {
+	manager.mu.Lock()
+	defer manager.mu.Unlock()
+
+	// remove listener
+	manager.removeListener()
+
+	// stop if started
+	manager.stop()
+
+	return nil
+}
+
+func (manager *StreamSinkManagerCtx) ListenersCount() int {
+	manager.listenersMu.Lock()
+	defer manager.listenersMu.Unlock()
+
+	return manager.listeners
+}
+
+func (manager *StreamSinkManagerCtx) Started() bool {
+	return manager.ListenersCount() > 0
+}
+
+func (manager *StreamSinkManagerCtx) createPipeline() error {
+	manager.pipelineMu.Lock()
+	defer manager.pipelineMu.Unlock()
+
+	if manager.pipeline != nil {
+		return types.ErrCapturePipelineAlreadyExists
+	}
+
+	var err error
+
+	manager.logger.Info().
+		Str("codec", manager.codec.Name).
+		Msgf("creating pipeline")
+
+	manager.pipeline, err = manager.pipelineFn()
+	if err != nil {
+		return err
+	}
+
+	manager.logger.Info().
+		Str("codec", manager.codec.Name).
+		Str("src", manager.pipeline.Src).
+		Msgf("created pipeline")
+
+	manager.pipeline.AttachAppsink("appsink")
+	manager.pipeline.Play()
+
+	manager.wg.Add(1)
+	pipeline := manager.pipeline
+
+	go func() {
+		manager.logger.Debug().Msg("started emitting samples")
+		defer manager.wg.Done()
+
+		for {
+			sample, ok := <-pipeline.Sample
+			if !ok {
+				manager.logger.Debug().Msg("stopped emitting samples")
+				return
+			}
+
+			manager.sampleFn(sample)
+		}
+	}()
+
+	return nil
+}
+
+func (manager *StreamSinkManagerCtx) destroyPipeline() {
+	manager.pipelineMu.Lock()
+	defer manager.pipelineMu.Unlock()
+
+	if manager.pipeline == nil {
+		return
+	}
+
+	manager.pipeline.Destroy()
+	manager.logger.Info().Msgf("destroying pipeline")
+	manager.pipeline = nil
+}