Fix memory leak from alloca fix

* Rework `alloca` fix to use new helper class for buffer allocations.
* Add missing `delete[]` for cleanup of the temporary playback buffer.

Signed-off-by: Emily Mabrey <emabrey@tenacityaudio.org>
Reference-to: https://github.com/tenacityteam/tenacity/issues/416
Reference-to: https://github.com/tenacityteam/tenacity/pull/412
Helped-by: Paul Licameli

src/AudioIO.cpp

@@ -464,6 +464,7 @@ time warp info and AudioIOListener and whether the playback is looped.
 #include "DBConnection.h"
 #include "ProjectFileIO.h"
 #include "WaveTrack.h"
+#include "AudioIOBufferHelper.h"
 
 #include "effects/RealtimeEffectManager.h"
 #include "prefs/QualitySettings.h"
@@ -3843,14 +3844,7 @@ bool AudioIoCallback::FillOutputBuffers(
    }
 
    // ------ MEMORY ALLOCATION ----------------------
-   // These are small structures.
+   std::unique_ptr<AudioIOBufferHelper> bufHelper = std::make_unique<AudioIOBufferHelper>(numPlaybackChannels, framesPerBuffer);
-   auto chans = new WaveTrack * [numPlaybackChannels];
-   auto tempBufs = new float* [numPlaybackChannels];
-
-   // And these are larger structures....
-   for (unsigned int c = 0; c < numPlaybackChannels; c++) {
-       tempBufs[c] = new float[framesPerBuffer];
-   }
    // ------ End of MEMORY ALLOCATION ---------------
 
    auto & em = RealtimeEffectManager::Get();
@@ -3882,7 +3876,7 @@ bool AudioIoCallback::FillOutputBuffers(
    for (unsigned t = 0; t < numPlaybackTracks; t++)
    {
       WaveTrack *vt = mPlaybackTracks[t].get();
-      chans[chanCnt] = vt;
+      bufHelper.get()->chans[chanCnt] = vt;
 
       // TODO: more-than-two-channels
       auto nextTrack =
@@ -3901,7 +3895,7 @@ bool AudioIoCallback::FillOutputBuffers(
          // IF mono THEN clear 'the other' channel.
          if ( lastChannel && (numPlaybackChannels>1)) {
             // TODO: more-than-two-channels
-            memset(tempBufs[1], 0, framesPerBuffer * sizeof(float));
+            memset(bufHelper.get()->tempBufs[1], 0, framesPerBuffer * sizeof(float));
          }
          drop = TrackShouldBeSilent( *vt );
          dropQuickly = drop;
@@ -3920,7 +3914,7 @@ bool AudioIoCallback::FillOutputBuffers(
       }
       else
       {
-         len = mPlaybackBuffers[t]->Get((samplePtr)tempBufs[chanCnt],
+         len = mPlaybackBuffers[t]->Get((samplePtr)bufHelper.get()->tempBufs[chanCnt],
                                                    floatSample,
                                                    toGet);
          // wxASSERT( len == toGet );
@@ -3931,7 +3925,7 @@ bool AudioIoCallback::FillOutputBuffers(
             // real-time demand in this thread (see bug 1932).  We
             // must supply something to the sound card, so pad it with
             // zeroes and not random garbage.
-            memset((void*)&tempBufs[chanCnt][len], 0,
+            memset((void*)&bufHelper.get()->tempBufs[chanCnt][len], 0,
                (framesPerBuffer - len) * sizeof(float));
          chanCnt++;
       }
@@ -3952,7 +3946,7 @@ bool AudioIoCallback::FillOutputBuffers(
       len = mMaxFramesOutput;
 
       if( !dropQuickly && selected )
-         len = em.RealtimeProcess(group, chanCnt, tempBufs, len);
+         len = em.RealtimeProcess(group, chanCnt, bufHelper.get()->tempBufs, len);
       group++;
 
       CallbackCheckCompletion(mCallbackReturn, len);
@@ -3971,17 +3965,13 @@ bool AudioIoCallback::FillOutputBuffers(
       // For example mono channels output to both left and right output channels.
       if (len > 0) for (int c = 0; c < chanCnt; c++)
       {
-         vt = chans[c];
+         vt = bufHelper.get()->chans[c];
 
-         if (vt->GetChannelIgnoringPan() == Track::LeftChannel ||
+         if (vt->GetChannelIgnoringPan() == Track::LeftChannel || vt->GetChannelIgnoringPan() == Track::MonoChannel )
-               vt->GetChannelIgnoringPan() == Track::MonoChannel )
+            AddToOutputChannel( 0, outputMeterFloats, outputFloats, bufHelper.get()->tempBufs[c], drop, len, vt);
-            AddToOutputChannel( 0, outputMeterFloats, outputFloats,
-               tempBufs[c], drop, len, vt);
 
-         if (vt->GetChannelIgnoringPan() == Track::RightChannel ||
+         if (vt->GetChannelIgnoringPan() == Track::RightChannel || vt->GetChannelIgnoringPan() == Track::MonoChannel  )
-               vt->GetChannelIgnoringPan() == Track::MonoChannel  )
+            AddToOutputChannel( 1, outputMeterFloats, outputFloats, bufHelper.get()->tempBufs[c], drop, len, vt);
-            AddToOutputChannel( 1, outputMeterFloats, outputFloats,
-               tempBufs[c], drop, len, vt);
       }
 
       chanCnt = 0;
@@ -4002,8 +3992,6 @@ bool AudioIoCallback::FillOutputBuffers(
    if (outputMeterFloats != outputFloats)
       ClampBuffer( outputMeterFloats, framesPerBuffer*numPlaybackChannels );
 
-   delete[] chans;
-   delete[] tempBufs;
    return false;
 }
 

src/AudioIO.h

@@ -580,8 +580,7 @@ protected:
    PlaybackSchedule mPlaybackSchedule;
 };
 
-class AUDACITY_DLL_API AudioIO final
+class AUDACITY_DLL_API AudioIO final : public AudioIoCallback
-   : public AudioIoCallback
 {
 
    AudioIO();

src/AudioIOBufferHelper.h

@@ -0,0 +1,42 @@
+#ifndef AUDIOIO_BUFFER_HELPER_H
+#define AUDIOIO_BUFFER_HELPER_H
+
+#include "AudioIO.h"
+#include "../libraries/lib-utility/MemoryX.h"
+
+class AudioIOBufferHelper
+{
+
+    private:
+
+        unsigned int numPlaybackChannels;
+        unsigned long framesPerBuffer;
+
+    public:
+        WaveTrack** chans;
+        float** tempBufs;
+
+        AudioIOBufferHelper(const unsigned int numPlaybackChannels, const unsigned long framesPerBuffer) {
+            this->numPlaybackChannels = numPlaybackChannels;
+            this->framesPerBuffer = framesPerBuffer;
+
+            this->chans = safenew WaveTrack * [numPlaybackChannels];
+            this->tempBufs = safenew float* [numPlaybackChannels];
+
+            for (unsigned int c = 0; c < numPlaybackChannels; c++) {
+                tempBufs[c] = safenew float[framesPerBuffer];
+            }
+        }
+
+        ~AudioIOBufferHelper() {
+            for (unsigned int c = 0; c < numPlaybackChannels; c++) {
+                delete[] tempBufs[c];
+            }
+
+            delete[] tempBufs;
+
+            delete[] chans;
+        }
+};
+
+#endif

src/CMakeLists.txt

@@ -100,6 +100,7 @@ list( APPEND SOURCES
       AudioIO.h
       AudioIOBase.cpp
       AudioIOBase.h
+      AudioIOBufferHelper.h
       AudioIOListener.h
       AutoRecoveryDialog.cpp
       AutoRecoveryDialog.h