MEDIA-1620: add 'deleteEmptyConferencesWithBarbells' to config, defau…

…lt value is false.

If true, empty conferences with existing barbell connections will be automatically deleted despite ICE-only activity after
config.mixerInactivityTimeoutMs timeout.

bridge/engine/EngineMixer.cpp

@@ -82,7 +82,8 @@ EngineMixer::EngineMixer(const std::string& id,
     assert(videoSsrcs.size() <= SsrcRewrite::ssrcArraySize);
 
     std::memset(_mixedData, 0, samplesPerFrame20ms * channelsPerFrame);
-    _iceReceived.test_and_set();
+    _iceReceivedOnRegularTransport.test_and_set();
+    _iceReceivedOnBarbellTransport.test_and_set();
 }
 
 EngineMixer::~EngineMixer() {}
@@ -1067,7 +1068,10 @@ void EngineMixer::processIncomingRtcpPackets(const uint64_t timestamp)
 
 void EngineMixer::processIceActivity(const uint64_t timestamp)
 {
-    if (!_iceReceived.test_and_set())
+    bool needToUpdate = !_iceReceivedOnBarbellTransport.test_and_set() && !_config.deleteEmptyConferencesWithBarbells;
+    needToUpdate |= !_iceReceivedOnRegularTransport.test_and_set();
+
+    if (needToUpdate)
     {
         // if it was cleared by any transport receiving ICE, we will now set the keep alive timestamp
         _lastReceiveTime = timestamp;
@@ -1590,6 +1594,10 @@ bool EngineMixer::asyncHandleSctpControl(const size_t endpointIdHash, memory::Un
 
 void EngineMixer::onIceReceived(transport::RtcTransport* transport, uint64_t timestamp)
 {
-    _iceReceived.clear();
+    if (EngineBarbell::isFromBarbell(transport->getTag())) {
+        _iceReceivedOnBarbellTransport.clear();
+    } else {
+         _iceReceivedOnRegularTransport.clear();
+    }
 }
 } // namespace bridge

bridge/engine/EngineMixer.h

@@ -385,7 +385,8 @@ class EngineMixer : public transport::DataReceiver
     memory::AudioPacketPoolAllocator& _audioAllocator;
 
     uint64_t _lastReceiveTime;
-    std::atomic_flag _iceReceived = ATOMIC_FLAG_INIT;
+    std::atomic_flag _iceReceivedOnRegularTransport = ATOMIC_FLAG_INIT;
+    std::atomic_flag _iceReceivedOnBarbellTransport = ATOMIC_FLAG_INIT;
     uint64_t _lastCounterCheck;
 
     std::unique_ptr<EngineStreamDirector> _engineStreamDirector;

config/Config.h

@@ -16,8 +16,10 @@ class Config : public ConfigReader
     CFG_PROP(std::string, logLevel, "INFO");
     CFG_PROP(bool, enableSrtpNullCipher, false);
 
-    // If mixer does not receive any packets during this timeout, it's considered abandoned and is garbage collected.
+    // If mixer does not receive any packets during this timeout, it's considered abandoned and is garbage collected...
     CFG_PROP(int, mixerInactivityTimeoutMs, 2 * 60 * 1000);
+    // ...unless it has barbell connections, and 'deleteEmptyConferencesWithBarbells' is false.
+    CFG_PROP(bool, deleteEmptyConferencesWithBarbells, false);
     CFG_PROP(int, numWorkerTreads, 0);
     CFG_PROP(std::string, logFile, "/tmp/smb.log");