From d122ff8d435f960fec9de4d247adeba418c677c3 Mon Sep 17 00:00:00 2001
From: Nicky <sl.nicky.ml@googlemail.com>
Date: Sun, 8 Apr 2018 18:26:48 +0200
Subject: [PATCH] Use LLCondition rather than LLMutex. Then we can conveniently
 .wait() in popBack rather then having to use a poll loop./

---
 indra/llcommon/llthreadsafequeue.h | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/indra/llcommon/llthreadsafequeue.h b/indra/llcommon/llthreadsafequeue.h
index 01109b2b27..c59a29e3b4 100644
--- a/indra/llcommon/llthreadsafequeue.h
+++ b/indra/llcommon/llthreadsafequeue.h
@@ -104,7 +104,7 @@ public:
 
 private:
 	std::deque< ElementT > mStorage;
-	LLMutex mLock;
+	LLCondition mLock;;
 	U32 mCapacity; // Really needed?
 };
 
@@ -132,6 +132,7 @@ void LLThreadSafeQueue<ElementT>::pushFront(ElementT const & element)
 			if( mStorage.size() < mCapacity )
 			{
 				mStorage.push_front( element );
+				mLock.signal();
 				return;
 			}
 		}
@@ -151,6 +152,7 @@ bool LLThreadSafeQueue<ElementT>::tryPushFront(ElementT const & element)
 		return false;
 
 	mStorage.push_front( element );
+	mLock.signal();
 	return true;
 }
 
@@ -160,16 +162,13 @@ ElementT LLThreadSafeQueue<ElementT>::popBack(void)
 {
 	while( true )
 	{
+		mLock.wait();
+		if( !mStorage.empty() )
 		{
-			LLMutexLock lck( &mLock );
-			if( !mStorage.empty() )
-			{
-				ElementT value = mStorage.back();
-				mStorage.pop_back();
-				return value;
-			}
+			ElementT value = mStorage.back();
+			mStorage.pop_back();
+			return value;
 		}
-		ms_sleep( 100 );
 	}
 }