From 0931fcea18c93998092484c6cc78609148c10c2e Mon Sep 17 00:00:00 2001
From: Reuben Thomas <reuk@users.noreply.github.com>
Date: Tue, 13 Feb 2018 16:51:41 +0000
Subject: [PATCH] Solved an issue where Ableton Live will deadlock when loading
 a plugin based on an AudioProcessorGraph.

---
 .../processors/juce_AudioProcessorGraph.cpp                | 7 +++----
 .../processors/juce_AudioProcessorGraph.h                  | 2 +-
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/modules/juce_audio_processors/processors/juce_AudioProcessorGraph.cpp b/modules/juce_audio_processors/processors/juce_AudioProcessorGraph.cpp
index 8f0fe3ddd5..7033f6e0e1 100644
--- a/modules/juce_audio_processors/processors/juce_AudioProcessorGraph.cpp
+++ b/modules/juce_audio_processors/processors/juce_AudioProcessorGraph.cpp
@@ -851,7 +851,7 @@ void AudioProcessorGraph::topologyChanged()
 {
     sendChangeMessage();
 
-    if (isPrepared)
+    if (isPrepared.get())
         triggerAsyncUpdate();
 }
 
@@ -1197,6 +1197,7 @@ void AudioProcessorGraph::buildRenderingSequence()
 void AudioProcessorGraph::handleAsyncUpdate()
 {
     buildRenderingSequence();
+    isPrepared = true;
 }
 
 //==============================================================================
@@ -1209,9 +1210,7 @@ void AudioProcessorGraph::prepareToPlay (double /*sampleRate*/, int estimatedSam
         renderSequenceDouble->prepareBuffers (estimatedSamplesPerBlock);
 
     clearRenderingSequence();
-    buildRenderingSequence();
-
-    isPrepared = true;
+    triggerAsyncUpdate();
 }
 
 bool AudioProcessorGraph::supportsDoublePrecisionProcessing() const
diff --git a/modules/juce_audio_processors/processors/juce_AudioProcessorGraph.h b/modules/juce_audio_processors/processors/juce_AudioProcessorGraph.h
index 3b23bc5fa1..ea9ad0157e 100644
--- a/modules/juce_audio_processors/processors/juce_AudioProcessorGraph.h
+++ b/modules/juce_audio_processors/processors/juce_AudioProcessorGraph.h
@@ -376,7 +376,7 @@ private:
 
     friend class AudioGraphIOProcessor;
 
-    bool isPrepared = false;
+    Atomic<bool> isPrepared { false };
 
     void topologyChanged();
     void handleAsyncUpdate() override;