From 8a92a771ba547d9d6a8bd1234e2e0b144a8bfcf5 Mon Sep 17 00:00:00 2001
From: andreykproductengine <andreykproductengine@lindenlab.com>
Date: Tue, 15 Jan 2019 22:27:28 +0200
Subject: SL-10291 Replace apr thread with standard C++11 functionality

---
 indra/llcommon/llthreadsafequeue.h | 135 ++++++++++++++++++++-----------------
 1 file changed, 72 insertions(+), 63 deletions(-)

(limited to 'indra/llcommon/llthreadsafequeue.h')

diff --git a/indra/llcommon/llthreadsafequeue.h b/indra/llcommon/llthreadsafequeue.h
index 45289ef0b4..b0bddac8e5 100644
--- a/indra/llcommon/llthreadsafequeue.h
+++ b/indra/llcommon/llthreadsafequeue.h
@@ -28,12 +28,20 @@
 #define LL_LLTHREADSAFEQUEUE_H
 
 #include "llexception.h"
+#include <deque>
 #include <string>
 
+#if LL_WINDOWS
+#pragma warning (push)
+#pragma warning (disable:4265)
+#endif
+// 'std::_Pad' : class has virtual functions, but destructor is not virtual
+#include <mutex>
+#include <condition_variable>
 
-struct apr_pool_t; // From apr_pools.h
-class LLThreadSafeQueueImplementation; // See below.
-
+#if LL_WINDOWS
+#pragma warning (pop)
+#endif
 
 //
 // A general queue exception.
@@ -64,31 +72,6 @@ public:
 	}
 };
 
-
-struct apr_queue_t; // From apr_queue.h
-
-
-//
-// Implementation details. 
-//
-class LL_COMMON_API LLThreadSafeQueueImplementation
-{
-public:
-	LLThreadSafeQueueImplementation(apr_pool_t * pool, unsigned int capacity);
-	~LLThreadSafeQueueImplementation();
-	void pushFront(void * element);
-	bool tryPushFront(void * element);
-	void * popBack(void);
-	bool tryPopBack(void *& element);
-	size_t size();
-	
-private:
-	bool mOwnsPool;
-	apr_pool_t * mPool;
-	apr_queue_t * mQueue;
-};
-
-
 //
 // Implements a thread safe FIFO.
 //
@@ -100,7 +83,7 @@ public:
 	
 	// If the pool is set to NULL one will be allocated and managed by this
 	// queue.
-	LLThreadSafeQueue(apr_pool_t * pool = 0, unsigned int capacity = 1024);
+	LLThreadSafeQueue(U32 capacity = 1024);
 	
 	// Add an element to the front of queue (will block if the queue has
 	// reached capacity).
@@ -128,77 +111,103 @@ public:
 	size_t size();
 
 private:
-	LLThreadSafeQueueImplementation mImplementation;
-};
-
+	std::deque< ElementT > mStorage;
+	U32 mCapacity;
 
+	std::mutex mLock;
+	std::condition_variable mCapacityCond;
+	std::condition_variable mEmptyCond;
+};
 
 // LLThreadSafeQueue
 //-----------------------------------------------------------------------------
 
-
 template<typename ElementT>
-LLThreadSafeQueue<ElementT>::LLThreadSafeQueue(apr_pool_t * pool, unsigned int capacity):
-	mImplementation(pool, capacity)
+LLThreadSafeQueue<ElementT>::LLThreadSafeQueue(U32 capacity) :
+mCapacity(capacity)
 {
-	; // No op.
 }
 
 
 template<typename ElementT>
 void LLThreadSafeQueue<ElementT>::pushFront(ElementT const & element)
 {
-	ElementT * elementCopy = new ElementT(element);
-	try {
-		mImplementation.pushFront(elementCopy);
-	} catch (LLThreadSafeQueueInterrupt) {
-		delete elementCopy;
-		throw;
-	}
+    while (true)
+    {
+        std::unique_lock<std::mutex> lock1(mLock);
+
+        if (mStorage.size() < mCapacity)
+        {
+            mStorage.push_front(element);
+            mEmptyCond.notify_one();
+            return;
+        }
+
+        // Storage Full. Wait for signal.
+        mCapacityCond.wait(lock1);
+    }
 }
 
 
 template<typename ElementT>
 bool LLThreadSafeQueue<ElementT>::tryPushFront(ElementT const & element)
 {
-	ElementT * elementCopy = new ElementT(element);
-	bool result = mImplementation.tryPushFront(elementCopy);
-	if(!result) delete elementCopy;
-	return result;
+    std::unique_lock<std::mutex> lock1(mLock, std::defer_lock);
+    if (!lock1.try_lock())
+        return false;
+
+    if (mStorage.size() >= mCapacity)
+        return false;
+
+    mStorage.push_front(element);
+    mEmptyCond.notify_one();
+    return true;
 }
 
 
 template<typename ElementT>
 ElementT LLThreadSafeQueue<ElementT>::popBack(void)
 {
-	ElementT * element = reinterpret_cast<ElementT *> (mImplementation.popBack());
-	ElementT result(*element);
-	delete element;
-	return result;
+    while (true)
+    {
+        std::unique_lock<std::mutex> lock1(mLock);
+
+        if (!mStorage.empty())
+        {
+            ElementT value = mStorage.back();
+            mStorage.pop_back();
+            mCapacityCond.notify_one();
+            return value;
+        }
+
+        // Storage empty. Wait for signal.
+        mEmptyCond.wait(lock1);
+    }
 }
 
 
 template<typename ElementT>
 bool LLThreadSafeQueue<ElementT>::tryPopBack(ElementT & element)
 {
-	void * storedElement;
-	bool result = mImplementation.tryPopBack(storedElement);
-	if(result) {
-		ElementT * elementPtr = reinterpret_cast<ElementT *>(storedElement); 
-		element = *elementPtr;
-		delete elementPtr;
-	} else {
-		; // No op.
-	}
-	return result;
+    std::unique_lock<std::mutex> lock1(mLock, std::defer_lock);
+    if (!lock1.try_lock())
+        return false;
+
+    if (mStorage.empty())
+        return false;
+
+    element = mStorage.back();
+    mStorage.pop_back();
+    mCapacityCond.notify_one();
+    return true;
 }
 
 
 template<typename ElementT>
 size_t LLThreadSafeQueue<ElementT>::size(void)
 {
-	return mImplementation.size();
+    std::lock_guard<std::mutex> lock(mLock);
+    return mStorage.size();
 }
 
-
 #endif
-- 
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