feat(hls): add native HLS (m3u8) download protocol (#1515)

internal/protocol/hls/config.go

@@ -0,0 +1,30 @@
+package hls
+
+const (
+	defaultSegmentConnections = 8
+	defaultMaxRetries         = 5
+	defaultTimeoutSeconds     = 30
+
+	// maxPrefetchSizeSegments caps the HEAD probing done at resolve time.
+	// Playlists larger than this skip size prefetch entirely.
+	maxPrefetchSizeSegments = 500
+)
+
+type config struct {
+	SegmentConnections    int  `json:"segmentConnections"`
+	MaxRetries            int  `json:"maxRetries"`
+	TimeoutSeconds        int  `json:"timeoutSeconds"`
+	PrefetchContentLength bool `json:"prefetchContentLength"`
+}
+
+func (c *config) normalize() {
+	if c.SegmentConnections <= 0 {
+		c.SegmentConnections = defaultSegmentConnections
+	}
+	if c.MaxRetries < 0 {
+		c.MaxRetries = defaultMaxRetries
+	}
+	if c.TimeoutSeconds <= 0 {
+		c.TimeoutSeconds = defaultTimeoutSeconds
+	}
+}