From 408b72c798cddb6d837cd09d83f3369f9f3b98f1 Mon Sep 17 00:00:00 2001
From: Hyunjin Song <tteu.ingog@gmail.com>
Date: Fri, 13 Jul 2018 10:40:24 +0900
Subject: [PATCH] Use tryLock in audio threads for VST/ZynAddSubFX (#4460)

Prevent loading VST or toggling ZynAddSubFX GUI
from blocking entire audio processing
---
 plugins/VstEffect/VstEffect.cpp     | 8 +++++---
 plugins/vestige/vestige.cpp         | 4 +---
 plugins/zynaddsubfx/ZynAddSubFx.cpp | 2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/plugins/VstEffect/VstEffect.cpp b/plugins/VstEffect/VstEffect.cpp
index ea0241a5a..05cc7a070 100644
--- a/plugins/VstEffect/VstEffect.cpp
+++ b/plugins/VstEffect/VstEffect.cpp
@@ -95,9 +95,11 @@ bool VstEffect::processAudioBuffer( sampleFrame * _buf, const fpp_t _frames )
 		sampleFrame * buf = new sampleFrame[_frames];
 #endif
 		memcpy( buf, _buf, sizeof( sampleFrame ) * _frames );
-		m_pluginMutex.lock();
-		m_plugin->process( buf, buf );
-		m_pluginMutex.unlock();
+		if (m_pluginMutex.tryLock())
+		{
+			m_plugin->process( buf, buf );
+			m_pluginMutex.unlock();
+		}
 
 		double out_sum = 0.0;
 		const float w = wetLevel();
diff --git a/plugins/vestige/vestige.cpp b/plugins/vestige/vestige.cpp
index 9ea053e8e..540c8b5ce 100644
--- a/plugins/vestige/vestige.cpp
+++ b/plugins/vestige/vestige.cpp
@@ -359,14 +359,12 @@ void vestigeInstrument::loadFile( const QString & _file )
 
 void vestigeInstrument::play( sampleFrame * _buf )
 {
-	m_pluginMutex.lock();
+	if (!m_pluginMutex.tryLock()) {return;}
 
 	const fpp_t frames = Engine::mixer()->framesPerPeriod();
 
 	if( m_plugin == NULL )
 	{
-		BufferManager::clear( _buf, frames );
-
 		m_pluginMutex.unlock();
 		return;
 	}
diff --git a/plugins/zynaddsubfx/ZynAddSubFx.cpp b/plugins/zynaddsubfx/ZynAddSubFx.cpp
index 8bba1f10f..8c1da751f 100644
--- a/plugins/zynaddsubfx/ZynAddSubFx.cpp
+++ b/plugins/zynaddsubfx/ZynAddSubFx.cpp
@@ -326,7 +326,7 @@ QString ZynAddSubFxInstrument::nodeName() const
 
 void ZynAddSubFxInstrument::play( sampleFrame * _buf )
 {
-	m_pluginMutex.lock();
+	if (!m_pluginMutex.tryLock()) {return;}
 	if( m_remotePlugin )
 	{
 		m_remotePlugin->process( NULL, _buf );