cache: use render job times to synchronize cache

Ensure old inaccurate jobs are never prioritized over current jobs.

app/render/audioplaybackcache.cpp

@@ -63,10 +63,14 @@ void AudioPlaybackCache::SetParameters(const AudioRenderingParams &params)
   emit Invalidated(invalidate_range);
 }
 
-void AudioPlaybackCache::WritePCM(const TimeRange &range, SampleBufferPtr samples)
+void AudioPlaybackCache::WritePCM(const TimeRange &range, SampleBufferPtr samples, const qint64 &job_time)
 {
   QMutexLocker locker(lock());
 
+  if (!JobIsCurrent(range, job_time)) {
+    return;
+  }
+
   QFile f(filename_);
   if (f.open(QFile::ReadWrite)) {
     qint64 start_offset = params_.time_to_bytes(range.in());
@@ -193,6 +197,13 @@ void AudioPlaybackCache::ShiftEvent(const rational &from, const rational &to)
   }
 }
 
+void AudioPlaybackCache::LengthChangedEvent(const rational& old, const rational& newlen)
+{
+  if (newlen < old) {
+    QFile(filename_).resize(params_.time_to_bytes(newlen));
+  }
+}
+
 const QString &AudioPlaybackCache::GetCacheFilename() const
 {
   return filename_;