initial code repo

[stor4nfv.git] / src / ceph / src / rbd_replay / BoundedBuffer.hpp

diff --git a/src/ceph/src/rbd_replay/BoundedBuffer.hpp b/src/ceph/src/rbd_replay/BoundedBuffer.hpp
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+++ b/src/ceph/src/rbd_replay/BoundedBuffer.hpp
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+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#ifndef _INCLUDED_BOUNDED_BUFFER_HPP
+#define _INCLUDED_BOUNDED_BUFFER_HPP
+
+#include <boost/bind.hpp>
+#include <boost/circular_buffer.hpp>
+#include <boost/thread/condition.hpp>
+#include <boost/thread/mutex.hpp>
+
+/**
+   Blocking, fixed-capacity, thread-safe FIFO queue useful for communicating between threads.
+   This code was taken from the Boost docs: http://www.boost.org/doc/libs/1_55_0/libs/circular_buffer/example/circular_buffer_bound_example.cpp
+ */
+template <class T>
+class BoundedBuffer {
+public:
+  typedef boost::circular_buffer<T> container_type;
+  typedef typename container_type::size_type size_type;
+  typedef typename container_type::value_type value_type;
+  typedef typename boost::call_traits<value_type>::param_type param_type;
+
+  explicit BoundedBuffer(size_type capacity) : m_unread(0), m_container(capacity) {
+  }
+
+  /**
+     Inserts an element into the queue.
+     Blocks if the queue is full.
+   */
+  void push_front(typename boost::call_traits<value_type>::param_type item) {
+    // `param_type` represents the "best" way to pass a parameter of type `value_type` to a method.
+    boost::mutex::scoped_lock lock(m_mutex);
+    m_not_full.wait(lock, boost::bind(&BoundedBuffer<value_type>::is_not_full, this));
+    m_container.push_front(item);
+    ++m_unread;
+    lock.unlock();
+    m_not_empty.notify_one();
+  }
+
+  /**
+     Removes an element from the queue.
+     Blocks if the queue is empty.
+  */
+  void pop_back(value_type* pItem) {
+    boost::mutex::scoped_lock lock(m_mutex);
+    m_not_empty.wait(lock, boost::bind(&BoundedBuffer<value_type>::is_not_empty, this));
+    *pItem = m_container[--m_unread];
+    lock.unlock();
+    m_not_full.notify_one();
+  }
+
+private:
+  BoundedBuffer(const BoundedBuffer&);             // Disabled copy constructor.
+  BoundedBuffer& operator= (const BoundedBuffer&); // Disabled assign operator.
+
+  bool is_not_empty() const {
+    return m_unread > 0;
+  }
+  bool is_not_full() const {
+    return m_unread < m_container.capacity();
+  }
+
+  size_type m_unread;
+  container_type m_container;
+  boost::mutex m_mutex;
+  boost::condition m_not_empty;
+  boost::condition m_not_full;
+};
+
+#endif