AudioServer: Added ability to get count of samples in the buffer queue

Now the AClientConnection can get the count of samples still in the
buffer queue.

Libraries/LibAudio/AClientConnection.cpp

@@ -41,3 +41,8 @@ void AClientConnection::set_main_mix_volume(int volume)
 {
     send_sync<AudioServer::SetMainMixVolume>(volume);
 }
+
+int AClientConnection::get_remaining_samples()
+{
+    return send_sync<AudioServer::GetRemainingSamples>()->remaining_samples();
+}

Libraries/LibAudio/AClientConnection.h

@@ -16,4 +16,6 @@ public:
 
     int get_main_mix_volume();
     void set_main_mix_volume(int);
+
+    int get_remaining_samples();
 };

Servers/AudioServer/ASClientConnection.cpp

@@ -71,3 +71,12 @@ OwnPtr<AudioServer::EnqueueBufferResponse> ASClientConnection::handle(const Audi
     m_queue->enqueue(ABuffer::create_with_shared_buffer(*shared_buffer, message.sample_count()));
     return make<AudioServer::EnqueueBufferResponse>(true);
 }
+
+OwnPtr<AudioServer::GetRemainingSamplesResponse> ASClientConnection::handle(const AudioServer::GetRemainingSamples&)
+{
+    int remaining = 0;
+    if(m_queue)
+        remaining = m_queue->get_remaining_samples();
+
+    return make<AudioServer::GetRemainingSamplesResponse>(remaining);
+}

Servers/AudioServer/ASClientConnection.h

@@ -22,6 +22,7 @@ private:
     virtual OwnPtr<AudioServer::GetMainMixVolumeResponse> handle(const AudioServer::GetMainMixVolume&) override;
     virtual OwnPtr<AudioServer::SetMainMixVolumeResponse> handle(const AudioServer::SetMainMixVolume&) override;
     virtual OwnPtr<AudioServer::EnqueueBufferResponse> handle(const AudioServer::EnqueueBuffer&) override;
+    virtual OwnPtr<AudioServer::GetRemainingSamplesResponse> handle(const AudioServer::GetRemainingSamples&) override;
 
     ASMixer& m_mixer;
     RefPtr<ASBufferQueue> m_queue;

Servers/AudioServer/ASMixer.cpp

@@ -100,5 +100,6 @@ ASBufferQueue::ASBufferQueue(ASClientConnection& client)
 
 void ASBufferQueue::enqueue(NonnullRefPtr<ABuffer>&& buffer)
 {
+    m_remaining_samples += buffer->sample_count();
     m_queue.enqueue(move(buffer));
 }

Servers/AudioServer/ASMixer.h

@@ -24,9 +24,13 @@ public:
     {
         while (!m_current && !m_queue.is_empty())
             m_current = m_queue.dequeue();
+
         if (!m_current)
             return false;
+
         sample = m_current->samples()[m_position++];
+        m_remaining_samples--;
+
         if (m_position >= m_current->sample_count()) {
             m_current = nullptr;
             m_position = 0;
@@ -35,16 +39,20 @@ public:
     }
 
     ASClientConnection* client() { return m_client.ptr(); }
+
     void clear()
     {
         m_queue.clear();
         m_position = 0;
     }
 
+    int get_remaining_samples() const { return m_remaining_samples; }
+
 private:
     RefPtr<ABuffer> m_current;
     Queue<NonnullRefPtr<ABuffer>> m_queue;
     int m_position { 0 };
+    int m_remaining_samples { 0 };
     WeakPtr<ASClientConnection> m_client;
 };
 

Servers/AudioServer/AudioServer.ipc

@@ -9,4 +9,6 @@ endpoint AudioServer
 
     // Buffer playback
     EnqueueBuffer(i32 buffer_id, int sample_count) => (bool success)
+
+    GetRemainingSamples() => (int remaining_samples)
 }