From cab34558ce64d4887edd9e415ecbba232377405c Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Wed, 5 Oct 2022 22:31:29 +0300
Subject: [PATCH] Support replacing a mixing channel stream

---
 libs/audio/include/psemek/audio/mixer.hpp | 3 +++
 libs/audio/source/mixer.cpp               | 9 +++++++++
 2 files changed, 12 insertions(+)

diff --git a/libs/audio/include/psemek/audio/mixer.hpp b/libs/audio/include/psemek/audio/mixer.hpp
index 7f401c88..cc464584 100644
--- a/libs/audio/include/psemek/audio/mixer.hpp
+++ b/libs/audio/include/psemek/audio/mixer.hpp
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <psemek/audio/stream.hpp>
+#include <psemek/util/function.hpp>
 
 #include <memory>
 
@@ -16,6 +17,8 @@ namespace psemek::audio
 
 			virtual bool is_stopped() const = 0;
 
+			virtual void replace(util::function<stream_ptr(stream_ptr)> modifier) = 0;
+
 			virtual ~channel() {}
 		};
 
diff --git a/libs/audio/source/mixer.cpp b/libs/audio/source/mixer.cpp
index 07379b85..52720ee8 100644
--- a/libs/audio/source/mixer.cpp
+++ b/libs/audio/source/mixer.cpp
@@ -18,6 +18,8 @@ namespace psemek::audio
 			void stop() override;
 
 			bool is_stopped() const override;
+
+			void replace(util::function<stream_ptr(stream_ptr)> modifier) override;
 		};
 
 		void channel_impl::stop()
@@ -30,6 +32,13 @@ namespace psemek::audio
 			return std::atomic_load(&stream) != nullptr;
 		}
 
+		void channel_impl::replace(util::function<stream_ptr(stream_ptr)> modifier)
+		{
+			stream_ptr stream = std::atomic_load(&(this->stream));
+			stream = modifier(std::move(stream));
+			std::atomic_store(&(this->stream), std::move(stream));
+		}
+
 		struct mixer_impl final
 			: mixer
 			, std::enable_shared_from_this<mixer_impl>