From 1a8cca3dcca0f4e59b5d25429b9b9a03962b1c30 Mon Sep 17 00:00:00 2001
From: Zach Pomerantz <zmp@umich.edu>
Date: Tue, 15 Mar 2016 10:51:55 -0700
Subject: [PATCH] Clarify use of procedural's dirty atomic flag

---
 libraries/procedural/src/procedural/Procedural.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/libraries/procedural/src/procedural/Procedural.cpp b/libraries/procedural/src/procedural/Procedural.cpp
index 071b07b48a..d3aed38198 100644
--- a/libraries/procedural/src/procedural/Procedural.cpp
+++ b/libraries/procedural/src/procedural/Procedural.cpp
@@ -77,6 +77,9 @@ void Procedural::parse(const QString& userDataJson) {
     // This will be called by Procedural::ready
     std::lock_guard<std::mutex> lock(_proceduralDataMutex);
     _proceduralData = proceduralData.toObject();
+
+    // Mark as dirty after modifying _proceduralData, but before releasing lock
+    // to avoid setting it after parsing has begun
     _proceduralDataDirty = true;
 }
 
@@ -166,9 +169,13 @@ void Procedural::parse(const QJsonObject& proceduralData) {
 
 bool Procedural::ready() {
     // Load any changes to the procedural
+    // Check for changes atomically, in case they are currently being made
     if (_proceduralDataDirty) {
         std::lock_guard<std::mutex> lock(_proceduralDataMutex);
         parse(_proceduralData);
+
+        // Reset dirty flag after reading _proceduralData, but before releasing lock
+        // to avoid resetting it after more data is set
         _proceduralDataDirty = false;
     }