Separate Index class to track streams via intrusive list

index.cc

@@ -0,0 +1,39 @@
+#include "index.h"
+
+namespace firesse {
+
+void Index::Add(Stream* stream) {
+	std::lock_guard l(mu_);
+
+	// Implicitly freshest
+	stream->fresher_ = nullptr;
+	stream->staler_ = freshest_;
+	if (stream->staler_) {
+		stream->staler_->fresher_ = stream;
+	}
+	freshest_ = stream;
+	if (!stalest_) {
+		stalest_ = stream;
+	}
+}
+
+void Index::Remove(Stream* stream) {
+	std::lock_guard l(mu_);
+
+	if (freshest_ == stream) {
+		freshest_ = stream->staler_;
+	}
+	if (stalest_ == stream) {
+		stalest_ = stream->fresher_;
+	}
+	if (stream->fresher_) {
+		stream->fresher_->staler_ = stream->staler_;
+		stream->fresher_ = nullptr;
+	}
+	if (stream->staler_) {
+		stream->staler_->fresher_ = stream->fresher_;
+		stream->staler_ = nullptr;
+	}
+}
+
+} // namespace firesse