Put callback in a member function, remove many more gAudioIO->

src/AudioIO.h

@@ -169,12 +169,47 @@ struct TransportTracks {
 // which seems not to implement the notes-off message correctly.
 #define AUDIO_IO_GB_MIDI_WORKAROUND
 
+/** brief The function which is called from PortAudio's callback thread
+ * context to collect and deliver audio for / from the sound device.
+ *
+ * This covers recording, playback, and doing both simultaneously. It is
+ * also invoked to do monitoring and software playthrough. Note that dealing
+ * with the two buffers needs some care to ensure that the right things
+ * happen for all possible cases.
+ * @param inputBuffer Buffer of length framesPerBuffer containing samples
+ * from the sound card, or null if not capturing audio. Note that the data
+ * type will depend on the format of audio data that was chosen when the
+ * stream was created (so could be floats or various integers)
+ * @param outputBuffer Uninitialised buffer of length framesPerBuffer which
+ * will be sent to the sound card after the callback, or null if not playing
+ * audio back.
+ * @param framesPerBuffer The length of the playback and recording buffers
+ * @param PaStreamCallbackTimeInfo Pointer to PortAudio time information
+ * structure, which tells us how long we have been playing / recording
+ * @param statusFlags PortAudio stream status flags
+ * @param userData pointer to user-defined data structure. Provided for
+ * flexibility by PortAudio, but not used by Audacity - the data is stored in
+ * the AudioIO class instead.
+ */
+int audacityAudioCallback(
+   const void *inputBuffer, void *outputBuffer,
+   unsigned long framesPerBuffer,
+   const PaStreamCallbackTimeInfo *timeInfo,
+   PaStreamCallbackFlags statusFlags, void *userData );
+
 class AUDACITY_DLL_API AudioIO final {
 
  public:
    AudioIO();
    ~AudioIO();
 
+   // This function executes in a thread spawned by the PortAudio library
+   int AudioCallback(
+      const void *inputBuffer, void *outputBuffer,
+      unsigned long framesPerBuffer,
+      const PaStreamCallbackTimeInfo *timeInfo,
+      const PaStreamCallbackFlags statusFlags, void *userData);
+
    AudioIOListener* GetListener() { return mListener; }
    void SetListener(AudioIOListener* listener);
 
@@ -780,34 +815,6 @@ private:
    static double mCachedBestRateIn;
    static double mCachedBestRateOut;
 
-   /** brief The function which is called from PortAudio's callback thread
-    * context to collect and deliver audio for / from the sound device.
-    *
-    * This covers recording, playback, and doing both simultaneously. It is
-    * also invoked to do monitoring and software playthrough. Note that dealing
-    * with the two buffers needs some care to ensure that the right things
-    * happen for all possible cases.
-    * @param inputBuffer Buffer of length framesPerBuffer containing samples
-    * from the sound card, or null if not capturing audio. Note that the data
-    * type will depend on the format of audio data that was chosen when the
-    * stream was created (so could be floats or various integers)
-    * @param outputBuffer Uninitialised buffer of length framesPerBuffer which
-    * will be sent to the sound card after the callback, or null if not playing
-    * audio back.
-    * @param framesPerBuffer The length of the playback and recording buffers
-    * @param PaStreamCallbackTimeInfo Pointer to PortAudio time information
-    * structure, which tells us how long we have been playing / recording
-    * @param statusFlags PortAudio stream status flags
-    * @param userData pointer to user-defined data structure. Provided for
-    * flexibility by PortAudio, but not used by Audacity - the data is stored in
-    * the AudioIO class instead.
-    */
-   friend int audacityAudioCallback(
-                const void *inputBuffer, void *outputBuffer,
-                unsigned long framesPerBuffer,
-                const PaStreamCallbackTimeInfo *timeInfo,
-                PaStreamCallbackFlags statusFlags, void *userData );
-
    // Serialize main thread and PortAudio thread's attempts to pause and change
    // the state used by the third, Audio thread.
    wxMutex mSuspendAudioThread;