audio_out: Mark several functions as const

These don't affect class state, so we can mark them as such.

src/audio_core/out/audio_out.cpp

@@ -72,7 +72,7 @@ Kernel::KReadableEvent& Out::GetBufferEvent() {
     return event->GetReadableEvent();
 }
 
-f32 Out::GetVolume() {
+f32 Out::GetVolume() const {
     std::scoped_lock l{parent_mutex};
     return system.GetVolume();
 }
@@ -82,17 +82,17 @@ void Out::SetVolume(const f32 volume) {
     system.SetVolume(volume);
 }
 
-bool Out::ContainsAudioBuffer(const u64 tag) {
+bool Out::ContainsAudioBuffer(const u64 tag) const {
     std::scoped_lock l{parent_mutex};
     return system.ContainsAudioBuffer(tag);
 }
 
-u32 Out::GetBufferCount() {
+u32 Out::GetBufferCount() const {
     std::scoped_lock l{parent_mutex};
     return system.GetBufferCount();
 }
 
-u64 Out::GetPlayedSampleCount() {
+u64 Out::GetPlayedSampleCount() const {
     std::scoped_lock l{parent_mutex};
     return system.GetPlayedSampleCount();
 }

src/audio_core/out/audio_out.h

@@ -102,7 +102,7 @@ public:
      *
      * @return The current volume.
      */
-    f32 GetVolume();
+    f32 GetVolume() const;
 
     /**
      * Set the system volume.
@@ -117,21 +117,21 @@ public:
      * @param tag - The tag to search for.
      * @return True if the buffer is in the system, otherwise false.
      */
-    bool ContainsAudioBuffer(u64 tag);
+    bool ContainsAudioBuffer(u64 tag) const;
 
     /**
      * Get the maximum number of buffers.
      *
      * @return The maximum number of buffers.
      */
-    u32 GetBufferCount();
+    u32 GetBufferCount() const;
 
     /**
      * Get the total played sample count for this audio out.
      *
      * @return The played sample count.
      */
-    u64 GetPlayedSampleCount();
+    u64 GetPlayedSampleCount() const;
 
 private:
     /// The AudioOut::Manager this audio out is registered with

src/audio_core/out/audio_out_system.cpp

@@ -27,11 +27,12 @@ void System::Finalize() {
     buffer_event->GetWritableEvent().Signal();
 }
 
-std::string_view System::GetDefaultOutputDeviceName() {
+std::string_view System::GetDefaultOutputDeviceName() const {
     return "DeviceOut";
 }
 
-Result System::IsConfigValid(std::string_view device_name, const AudioOutParameter& in_params) {
+Result System::IsConfigValid(std::string_view device_name,
+                             const AudioOutParameter& in_params) const {
     if ((device_name.size() > 0) && (device_name != GetDefaultOutputDeviceName())) {
         return Service::Audio::ERR_INVALID_DEVICE_NAME;
     }
@@ -200,11 +201,11 @@ void System::SetVolume(const f32 volume_) {
     session->SetVolume(volume_);
 }
 
-bool System::ContainsAudioBuffer(const u64 tag) {
+bool System::ContainsAudioBuffer(const u64 tag) const {
     return buffers.ContainsBuffer(tag);
 }
 
-u32 System::GetBufferCount() {
+u32 System::GetBufferCount() const {
     return buffers.GetAppendedRegisteredCount();
 }
 

src/audio_core/out/audio_out_system.h

@@ -68,7 +68,7 @@ public:
      *
      * @return The default audio output device name.
      */
-    std::string_view GetDefaultOutputDeviceName();
+    std::string_view GetDefaultOutputDeviceName() const;
 
     /**
      * Is the given initialize config valid?
@@ -77,7 +77,7 @@ public:
      * @param in_params   - Input parameters, see AudioOutParameter.
      * @return Result code.
      */
-    Result IsConfigValid(std::string_view device_name, const AudioOutParameter& in_params);
+    Result IsConfigValid(std::string_view device_name, const AudioOutParameter& in_params) const;
 
     /**
      * Initialize this system.
@@ -209,14 +209,14 @@ public:
      * @param tag - Unique tag to search for.
      * @return True if the buffer is in the system, otherwise false.
      */
-    bool ContainsAudioBuffer(u64 tag);
+    bool ContainsAudioBuffer(u64 tag) const;
 
     /**
      * Get the maximum number of usable buffers (default 32).
      *
      * @return The number of buffers.
      */
-    u32 GetBufferCount();
+    u32 GetBufferCount() const;
 
     /**
      * Get the total number of samples played by this system.