Switch from MessageBuffer to Queue for pipeline comms

1 files changed, 57 insertions, 0 deletions

diff --git a/src/audio/include/stream_event.hpp b/src/audio/include/stream_event.hpp
new file mode 100644
index 00000000..4dfdab41
--- /dev/null
+++ b/src/audio/include/stream_event.hpp
@@ -0,0 +1,57 @@
+#pragma once
+
+#include <memory>
+
+#include "freertos/FreeRTOS.h"
+#include "freertos/queue.h"
+
+#include "span.hpp"
+#include "stream_info.hpp"
+
+namespace audio {
+
+struct StreamEvent {
+  static auto CreateStreamInfo(QueueHandle_t source,
+                               std::unique_ptr<StreamInfo> payload)
+      -> std::unique_ptr<StreamEvent>;
+  static auto CreateChunkData(QueueHandle_t source, std::size_t chunk_size)
+      -> std::unique_ptr<StreamEvent>;
+  static auto CreateChunkNotification(QueueHandle_t source)
+      -> std::unique_ptr<StreamEvent>;
+
+  StreamEvent();
+  ~StreamEvent();
+  StreamEvent(StreamEvent&&);
+
+  QueueHandle_t source;
+
+  enum {
+    UNINITIALISED,
+    STREAM_INFO,
+    CHUNK_DATA,
+    CHUNK_NOTIFICATION,
+  } tag;
+
+  union {
+    std::unique_ptr<StreamInfo> stream_info;
+
+    // Scott Meyers says:
+    // `About the only situation I can conceive of when a std::unique_ptr<T[]>
+    // would make sense would be when you’re using a C-like API that returns a
+    // raw pointer to a heap array that you assume ownership of.`
+    // :-)
+
+    struct {
+      std::unique_ptr<std::byte*> raw_bytes;
+      cpp::span<std::byte> bytes;
+    } chunk_data;
+
+    // FIXME: It would be nice to also support a pointer to himem data here, to
+    // save a little ordinary heap space.
+  };
+
+  StreamEvent(const StreamEvent&) = delete;
+  StreamEvent& operator=(const StreamEvent&) = delete;
+};
+
+}  // namespace audio