From eb47f6543f152fd0aaff7106780468f76ea5e04b Mon Sep 17 00:00:00 2001
From: Kevin Matz <kevin@company235.com>
Date: Fri, 9 Dec 2022 23:09:52 -0500
Subject: [PATCH] correct locking semantics

---
 protocol/esta/sacn/arbitratinguniverse.cpp |  7 ++---
 protocol/esta/sacn/universe.cpp            | 30 ++++++++++++----------
 2 files changed, 20 insertions(+), 17 deletions(-)

diff --git a/protocol/esta/sacn/arbitratinguniverse.cpp b/protocol/esta/sacn/arbitratinguniverse.cpp
index 5a3d56a..8ba79ab 100644
--- a/protocol/esta/sacn/arbitratinguniverse.cpp
+++ b/protocol/esta/sacn/arbitratinguniverse.cpp
@@ -139,7 +139,9 @@ void ArbitratingUniverse::deleteSourceUniverse(const DATA::data_header& src)
       return;
     if (sources_.size() == 1 && hold_last_look_)
       return;
-    std::unique_lock lk_wctl(lk_ctl);
+  }
+  {
+    std::unique_lock lk_ctl(mtx_control);
     sources_.erase(src);
   }
   doListChangeCallbacks();
@@ -187,7 +189,6 @@ std::shared_ptr<void> ArbitratingUniverse::onSourceListChange(std::function<void
  */
 void ArbitratingUniverse::doListChangeCallbacks()
 {
-  std::shared_lock lk_ctl(mtx_control);
   for (auto it = cb_sourceListChange.begin(); it != cb_sourceListChange.end();)
   {
     if (auto sp = it->lock())
@@ -197,7 +198,7 @@ void ArbitratingUniverse::doListChangeCallbacks()
     }
     else
     { // or remove the callback
-      std::unique_lock lk_wctl(lk_ctl);
+      std::unique_lock lk_ctl(mtx_control);
       it = cb_sourceListChange.erase(it);
     }
   }
diff --git a/protocol/esta/sacn/universe.cpp b/protocol/esta/sacn/universe.cpp
index b28a929..f688ec0 100644
--- a/protocol/esta/sacn/universe.cpp
+++ b/protocol/esta/sacn/universe.cpp
@@ -95,25 +95,27 @@ bool Universe::isSyncronized()
  */
 void Universe::synchronize(uint8_t sequence_number)
 {
-    std::shared_lock lk_ctl(mtx_control);
     if (!sync_data_)
         return;
-
-    /// > \cite sACN 6.7.2 Sequence Numbering
-    /// >
-    /// > Having first received a packet with sequence number A,
-    /// > a second packet with sequence number B arrives.
-    /// > If, using signed 8-bit binary arithmetic, B - A
-    /// > is less than or equal to 0, but greater than -20,
-    /// > then the packet containing sequence number B shall be deemed out of
-    /// > sequence and discarded.
-    auto a = sync_sequence_;
-    auto b = sequence_number;
-    int8_t dif = b - a;
+    int8_t dif;
+    {
+      std::shared_lock lk_ctl(mtx_control);
+      /// > \cite sACN 6.7.2 Sequence Numbering
+      /// >
+      /// > Having first received a packet with sequence number A,
+      /// > a second packet with sequence number B arrives.
+      /// > If, using signed 8-bit binary arithmetic, B - A
+      /// > is less than or equal to 0, but greater than -20,
+      /// > then the packet containing sequence number B shall be deemed out of
+      /// > sequence and discarded.
+      auto a = sync_sequence_;
+      auto b = sequence_number;
+      dif = b - a;
+    }
     if (dif <= 0 && dif > -20)
         return;
     {
-        std::unique_lock lk_wctl(lk_ctl);
+        std::unique_lock lk_ctl(mtx_control);
         sync_sequence_ = sequence_number;
     }
     DMX::Universe::setData(*sync_data_);