From 7d2310795f6432a6a17a2cbc9be8b36e330f7680 Mon Sep 17 00:00:00 2001
From: reuk <reuk@users.noreply.github.com>
Date: Fri, 13 Dec 2019 22:44:20 +0000
Subject: [PATCH] Threadsafety improvements

---
 .../juce_audio_basics/mpe/juce_MPEUtils.cpp   |  2 +-
 .../processors/juce_AudioProcessorGraph.cpp   | 42 ++++++++++++++-----
 .../processors/juce_AudioProcessorGraph.h     |  3 +-
 .../juce_AudioProcessorValueTreeState.cpp     |  5 ++-
 4 files changed, 38 insertions(+), 14 deletions(-)

diff --git a/modules/juce_audio_basics/mpe/juce_MPEUtils.cpp b/modules/juce_audio_basics/mpe/juce_MPEUtils.cpp
index b8d973c20a..8ebc185b70 100644
--- a/modules/juce_audio_basics/mpe/juce_MPEUtils.cpp
+++ b/modules/juce_audio_basics/mpe/juce_MPEUtils.cpp
@@ -49,7 +49,7 @@ MPEChannelAssigner::MPEChannelAssigner (Range<int> channelRange)
 
 int MPEChannelAssigner::findMidiChannelForNewNote (int noteNumber) noexcept
 {
-    if (numChannels == 1)
+    if (numChannels <= 1)
         return firstChannel;
 
     for (auto ch = firstChannel; (isLegacy || zone->isLowerZone() ? ch <= lastChannel : ch >= lastChannel); ch += channelIncrement)
diff --git a/modules/juce_audio_processors/processors/juce_AudioProcessorGraph.cpp b/modules/juce_audio_processors/processors/juce_AudioProcessorGraph.cpp
index 5f5c00da4e..462c3120cb 100644
--- a/modules/juce_audio_processors/processors/juce_AudioProcessorGraph.cpp
+++ b/modules/juce_audio_processors/processors/juce_AudioProcessorGraph.cpp
@@ -885,6 +885,7 @@ AudioProcessorGraph::AudioProcessorGraph()
 
 AudioProcessorGraph::~AudioProcessorGraph()
 {
+    cancelPendingUpdate();
     clearRenderingSequence();
     clear();
 }
@@ -962,6 +963,8 @@ AudioProcessorGraph::Node::Ptr AudioProcessorGraph::addNode (std::unique_ptr<Aud
 
 bool AudioProcessorGraph::removeNode (NodeID nodeId)
 {
+    const ScopedLock sl (getCallbackLock());
+
     for (int i = nodes.size(); --i >= 0;)
     {
         if (nodes.getUnchecked(i)->nodeID == nodeId)
@@ -1227,22 +1230,34 @@ void AudioProcessorGraph::buildRenderingSequence()
         RenderSequenceBuilder<RenderSequenceDouble> builderD (*this, *newSequenceD);
     }
 
+    struct SampleRateAndBlockSize final
+    {
+        double sampleRate;
+        int blockSize;
+    };
+
+    const auto blockDetails = [&]
     {
         const ScopedLock sl (getCallbackLock());
-        newSequenceF->prepareBuffers (getBlockSize());
-        newSequenceD->prepareBuffers (getBlockSize());
-    }
+        auto details = SampleRateAndBlockSize { getSampleRate(), getBlockSize() };
+        newSequenceF->prepareBuffers (details.blockSize);
+        newSequenceD->prepareBuffers (details.blockSize);
+        return details;
+    }();
 
     if (anyNodesNeedPreparing())
     {
-        {
-            const ScopedLock sl (getCallbackLock());
-            renderSequenceFloat.reset();
-            renderSequenceDouble.reset();
-        }
+        const ScopedLock sl (getCallbackLock());
+        renderSequenceFloat.reset();
+        renderSequenceDouble.reset();
 
         for (auto* node : nodes)
-            node->prepare (getSampleRate(), getBlockSize(), this, getProcessingPrecision());
+            node->prepare (blockDetails.sampleRate,
+                           blockDetails.blockSize,
+                           this,
+                           getProcessingPrecision());
+
+        isPrepared = 1;
     }
 
     const ScopedLock sl (getCallbackLock());
@@ -1254,13 +1269,16 @@ void AudioProcessorGraph::buildRenderingSequence()
 void AudioProcessorGraph::handleAsyncUpdate()
 {
     buildRenderingSequence();
-    isPrepared = 1;
 }
 
 //==============================================================================
 void AudioProcessorGraph::prepareToPlay (double sampleRate, int estimatedSamplesPerBlock)
 {
-    setRateAndBufferSizeDetails (sampleRate, estimatedSamplesPerBlock);
+    {
+        const ScopedLock sl (getCallbackLock());
+        setRateAndBufferSizeDetails (sampleRate, estimatedSamplesPerBlock);
+    }
+
     clearRenderingSequence();
 
     if (MessageManager::getInstance()->isThisTheMessageThread())
@@ -1278,6 +1296,8 @@ void AudioProcessorGraph::releaseResources()
 {
     const ScopedLock sl (getCallbackLock());
 
+    cancelPendingUpdate();
+
     isPrepared = 0;
 
     for (auto* n : nodes)
diff --git a/modules/juce_audio_processors/processors/juce_AudioProcessorGraph.h b/modules/juce_audio_processors/processors/juce_AudioProcessorGraph.h
index ec77862b5d..5fd6dfa98d 100644
--- a/modules/juce_audio_processors/processors/juce_AudioProcessorGraph.h
+++ b/modules/juce_audio_processors/processors/juce_AudioProcessorGraph.h
@@ -145,7 +145,8 @@ public:
 
         const std::unique_ptr<AudioProcessor> processor;
         Array<Connection> inputs, outputs;
-        std::atomic<bool> isPrepared { false }, bypassed { false };
+        bool isPrepared = false;
+        std::atomic<bool> bypassed { false };
 
         Node (NodeID, std::unique_ptr<AudioProcessor>) noexcept;
 
diff --git a/modules/juce_audio_processors/utilities/juce_AudioProcessorValueTreeState.cpp b/modules/juce_audio_processors/utilities/juce_AudioProcessorValueTreeState.cpp
index cd0185c261..252dad8f14 100644
--- a/modules/juce_audio_processors/utilities/juce_AudioProcessorValueTreeState.cpp
+++ b/modules/juce_audio_processors/utilities/juce_AudioProcessorValueTreeState.cpp
@@ -258,7 +258,10 @@ AudioProcessorValueTreeState::AudioProcessorValueTreeState (AudioProcessor& p, U
     state.addListener (this);
 }
 
-AudioProcessorValueTreeState::~AudioProcessorValueTreeState() {}
+AudioProcessorValueTreeState::~AudioProcessorValueTreeState()
+{
+    stopTimer();
+}
 
 //==============================================================================
 RangedAudioParameter* AudioProcessorValueTreeState::createAndAddParameter (const String& paramID,