From 1bf1084f2b10c3b47fd1a588d85d21ed0eb41d0c Mon Sep 17 00:00:00 2001
From: Lorry Tar Creator <lorry-tar-importer@lorry>
Date: Tue, 27 Jun 2017 06:07:23 +0000
Subject: webkitgtk-2.16.5

---
 Source/WTF/wtf/SynchronizedFixedQueue.h | 121 ++++++++++++++++++++++++++++++++
 1 file changed, 121 insertions(+)
 create mode 100644 Source/WTF/wtf/SynchronizedFixedQueue.h

(limited to 'Source/WTF/wtf/SynchronizedFixedQueue.h')

diff --git a/Source/WTF/wtf/SynchronizedFixedQueue.h b/Source/WTF/wtf/SynchronizedFixedQueue.h
new file mode 100644
index 000000000..15f97f90e
--- /dev/null
+++ b/Source/WTF/wtf/SynchronizedFixedQueue.h
@@ -0,0 +1,121 @@
+/*
+ * Copyright (C) 2016 Apple Inc.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <wtf/Condition.h>
+#include <wtf/Deque.h>
+#include <wtf/HashSet.h>
+#include <wtf/Lock.h>
+#include <wtf/Locker.h>
+
+namespace WTF {
+
+template<typename T, size_t BufferSize>
+class SynchronizedFixedQueue {
+public:
+    SynchronizedFixedQueue()
+    {
+        static_assert(!((BufferSize - 1) & BufferSize), "BufferSize must be power of 2.");
+    }
+    
+    void open()
+    {
+        LockHolder lockHolder(m_mutex);
+        if (m_open)
+            return;
+
+        // Restore the queue to its original state.
+        m_open = true;
+        m_queue.clear();
+    }
+    
+    void close()
+    {
+        LockHolder lockHolder(m_mutex);
+        if (!m_open)
+            return;
+
+        // Wake all the sleeping threads up with a closing state.
+        m_open = false;
+        m_condition.notifyAll();
+    }
+    
+    bool isOpen()
+    {
+        LockHolder lockHolder(m_mutex);
+        return m_open;
+    }
+
+    bool enqueue(const T& value)
+    {
+        LockHolder lockHolder(m_mutex);
+
+        // Wait for an empty place to be available in the queue.
+        m_condition.wait(m_mutex, [this]() { return !m_open || m_queue.size() < BufferSize; });
+        
+        // The queue is closing, exit immediately.
+        if (!m_open)
+            return false;
+        
+        // Add the item in the queue.
+        m_queue.append(value);
+
+        // Notify the other threads that an item was added to the queue.
+        m_condition.notifyAll();
+        return true;
+    }
+    
+    bool dequeue(T& value)
+    {
+        LockHolder lockHolder(m_mutex);
+        
+        // Wait for an item to be added.
+        m_condition.wait(m_mutex, [this]() { return !m_open || m_queue.size(); });
+
+        // The queue is closing, exit immediately.
+        if (!m_open)
+            return false;
+
+        // Get a copy from m_queue.first and then remove it.
+        value = m_queue.first();
+        m_queue.removeFirst();
+
+        // Notify the other threads that an item was removed from the queue.
+        m_condition.notifyAll();
+        return true;
+    }
+
+private:
+    Lock m_mutex;
+    Condition m_condition;
+
+    bool m_open { true };
+    Deque<T, BufferSize> m_queue;
+};
+
+}
+
+using WTF::SynchronizedFixedQueue;
-- 
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