audio_in: Mark several functions as const

These functions don't modify class state, so we can mark them as such

src/audio_core/in/audio_in.cpp

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

src/audio_core/in/audio_in.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 in.
      *
      * @return The played sample count.
      */
-    u64 GetPlayedSampleCount();
+    u64 GetPlayedSampleCount() const;
 
 private:
     /// The AudioIn::Manager this audio in is registered with

src/audio_core/in/audio_in_system.cpp

@@ -34,16 +34,16 @@ size_t System::GetSessionId() const {
     return session_id;
 }
 
-std::string_view System::GetDefaultDeviceName() {
+std::string_view System::GetDefaultDeviceName() const {
     return "BuiltInHeadset";
 }
 
-std::string_view System::GetDefaultUacDeviceName() {
+std::string_view System::GetDefaultUacDeviceName() const {
     return "Uac";
 }
 
 Result System::IsConfigValid(const std::string_view device_name,
-                             const AudioInParameter& in_params) {
+                             const AudioInParameter& in_params) const {
     if ((device_name.size() > 0) &&
         (device_name != GetDefaultDeviceName() && device_name != GetDefaultUacDeviceName())) {
         return Service::Audio::ERR_INVALID_DEVICE_NAME;
@@ -202,11 +202,11 @@ 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/in/audio_in_system.h

@@ -68,7 +68,7 @@ public:
      *
      * @return The default audio input device name.
      */
-    std::string_view GetDefaultDeviceName();
+    std::string_view GetDefaultDeviceName() const;
 
     /**
      * Get the default USB audio input device name.
@@ -77,7 +77,7 @@ public:
      *
      * @return The default USB audio input device name.
      */
-    std::string_view GetDefaultUacDeviceName();
+    std::string_view GetDefaultUacDeviceName() const;
 
     /**
      * Is the given initialize config valid?
@@ -86,7 +86,7 @@ public:
      * @param in_params   - Input parameters, see AudioInParameter.
      * @return Result code.
      */
-    Result IsConfigValid(std::string_view device_name, const AudioInParameter& in_params);
+    Result IsConfigValid(std::string_view device_name, const AudioInParameter& in_params) const;
 
     /**
      * Initialize this system.
@@ -218,14 +218,14 @@ 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.