decouple EffectStatesMapArray from EffectChain

This fixes a crash deleting EffectStates after starting up with an
effect unit assigned to multiple input channels.
EffectChain::enableForInputChannel kept reusing the same array for
EffectStates and putting a pointer to this on the effects MessagePipe.
That assumed that the engine had a chance to process the message to load
the states by calling EffectProcessorImpl::loadStatesForInputChannel
before the next call to EffectChain::enableForInputChannel. On startup,
before the engine starts, this assumption is not true. The result was
that EffectProcessorImpl ended up storing pointers to the same
EffectStates for multiple input channels. This caused a crash when
~EffectProcessorImpl tried to delete the EffectStates for the second
input channel because the EffectState had already been deleted when
deleting the EffectStates for the first input channel.

Fixes https://bugs.launchpad.net/mixxx/+bug/1740531

1 files changed, 0 insertions, 1 deletions

diff --git a/src/effects/effectchain.h b/src/effects/effectchain.h
index 160ce8b113..cedecdf80e 100644
--- a/src/effects/effectchain.h
+++ b/src/effects/effectchain.h
@@ -123,7 +123,6 @@ class EffectChain : public QObject {
     QList<EffectPointer> m_effects;
     EngineEffectChain* m_pEngineEffectChain;
     bool m_bAddedToEngine;
-    EffectStatesMapArray m_effectStatesMapArray;
 
     DISALLOW_COPY_AND_ASSIGN(EffectChain);
 };