audio_renderer: Replace includes with forward declarations where applicable

Avoids including unnecessary headers within the audio_renderer.h header,
lessening the likelihood of needing to rebuild source files including
this header if they ever change.

Given std::vector allows forward declaring contained types, we can move
VoiceState to the cpp file and hide the implementation entirely.

src/audio_core/audio_renderer.cpp

@@ -3,9 +3,12 @@
 // Refer to the license.txt file included.
 
 #include "audio_core/algorithm/interpolate.h"
+#include "audio_core/audio_out.h"
 #include "audio_core/audio_renderer.h"
+#include "audio_core/codec.h"
 #include "common/assert.h"
 #include "common/logging/log.h"
+#include "core/hle/kernel/event.h"
 #include "core/memory.h"
 
 namespace AudioCore {
@@ -13,6 +16,41 @@ namespace AudioCore {
 constexpr u32 STREAM_SAMPLE_RATE{48000};
 constexpr u32 STREAM_NUM_CHANNELS{2};
 
+class AudioRenderer::VoiceState {
+public:
+    bool IsPlaying() const {
+        return is_in_use && info.play_state == PlayState::Started;
+    }
+
+    const VoiceOutStatus& GetOutStatus() const {
+        return out_status;
+    }
+
+    const VoiceInfo& GetInfo() const {
+        return info;
+    }
+
+    VoiceInfo& Info() {
+        return info;
+    }
+
+    void SetWaveIndex(std::size_t index);
+    std::vector<s16> DequeueSamples(std::size_t sample_count);
+    void UpdateState();
+    void RefreshBuffer();
+
+private:
+    bool is_in_use{};
+    bool is_refresh_pending{};
+    std::size_t wave_index{};
+    std::size_t offset{};
+    Codec::ADPCMState adpcm_state{};
+    InterpolationState interp_state{};
+    std::vector<s16> samples;
+    VoiceOutStatus out_status{};
+    VoiceInfo info{};
+};
+
 AudioRenderer::AudioRenderer(AudioRendererParameter params,
                              Kernel::SharedPtr<Kernel::Event> buffer_event)
     : worker_params{params}, buffer_event{buffer_event}, voices(params.voice_count) {
@@ -27,6 +65,8 @@ AudioRenderer::AudioRenderer(AudioRendererParameter params,
     QueueMixedBuffer(2);
 }
 
+AudioRenderer::~AudioRenderer() = default;
+
 u32 AudioRenderer::GetSampleRate() const {
     return worker_params.sample_rate;
 }

src/audio_core/audio_renderer.h

@@ -8,16 +8,20 @@
 #include <memory>
 #include <vector>
 
-#include "audio_core/algorithm/interpolate.h"
-#include "audio_core/audio_out.h"
-#include "audio_core/codec.h"
 #include "audio_core/stream.h"
+#include "common/common_funcs.h"
 #include "common/common_types.h"
 #include "common/swap.h"
-#include "core/hle/kernel/event.h"
+#include "core/hle/kernel/object.h"
+
+namespace Kernel {
+class Event;
+}
 
 namespace AudioCore {
 
+class AudioOut;
+
 enum class PlayState : u8 {
     Started = 0,
     Stopped = 1,
@@ -158,6 +162,8 @@ static_assert(sizeof(UpdateDataHeader) == 0x40, "UpdateDataHeader has wrong size
 class AudioRenderer {
 public:
     AudioRenderer(AudioRendererParameter params, Kernel::SharedPtr<Kernel::Event> buffer_event);
+    ~AudioRenderer();
+
     std::vector<u8> UpdateAudioRenderer(const std::vector<u8>& input_params);
     void QueueMixedBuffer(Buffer::Tag tag);
     void ReleaseAndQueueBuffers();
@@ -166,45 +172,12 @@ public:
     u32 GetMixBufferCount() const;
 
 private:
-    class VoiceState {
+    class VoiceState;
-    public:
-        bool IsPlaying() const {
-            return is_in_use && info.play_state == PlayState::Started;
-        }
-
-        const VoiceOutStatus& GetOutStatus() const {
-            return out_status;
-        }
-
-        const VoiceInfo& GetInfo() const {
-            return info;
-        }
-
-        VoiceInfo& Info() {
-            return info;
-        }
-
-        void SetWaveIndex(std::size_t index);
-        std::vector<s16> DequeueSamples(std::size_t sample_count);
-        void UpdateState();
-        void RefreshBuffer();
-
-    private:
-        bool is_in_use{};
-        bool is_refresh_pending{};
-        std::size_t wave_index{};
-        std::size_t offset{};
-        Codec::ADPCMState adpcm_state{};
-        InterpolationState interp_state{};
-        std::vector<s16> samples;
-        VoiceOutStatus out_status{};
-        VoiceInfo info{};
-    };
 
     AudioRendererParameter worker_params;
     Kernel::SharedPtr<Kernel::Event> buffer_event;
     std::vector<VoiceState> voices;
-    std::unique_ptr<AudioCore::AudioOut> audio_out;
+    std::unique_ptr<AudioOut> audio_out;
     AudioCore::StreamPtr stream;
 };