comparison DEPENDENCIES/generic/include/boost/log/sinks/block_on_overflow.hpp @ 16:2665513ce2d3

Add boost headers

+/*
+ *          Copyright Andrey Semashev 2007 - 2013.
+ * Distributed under the Boost Software License, Version 1.0.
+ *    (See accompanying file LICENSE_1_0.txt or copy at
+ *          http://www.boost.org/LICENSE_1_0.txt)
+ */
+/*!
+ * \file   block_on_overflow.hpp
+ * \author Andrey Semashev
+ * \date   04.01.2012
+ *
+ * The header contains implementation of \c block_on_overflow strategy for handling
+ * queue overflows in bounded queues for the asynchronous sink frontend.
+ */
+
+#ifndef BOOST_LOG_SINKS_BLOCK_ON_OVERFLOW_HPP_INCLUDED_
+#define BOOST_LOG_SINKS_BLOCK_ON_OVERFLOW_HPP_INCLUDED_
+
+#include <boost/log/detail/config.hpp>
+
+#ifdef BOOST_HAS_PRAGMA_ONCE
+#pragma once
+#endif
+
+#if defined(BOOST_LOG_NO_THREADS)
+#error Boost.Log: This header content is only supported in multithreaded environment
+#endif
+
+#include <boost/intrusive/options.hpp>
+#include <boost/intrusive/list.hpp>
+#include <boost/intrusive/list_hook.hpp>
+#include <boost/thread/condition_variable.hpp>
+#include <boost/log/core/record_view.hpp>
+#include <boost/log/detail/header.hpp>
+
+namespace boost {
+
+BOOST_LOG_OPEN_NAMESPACE
+
+namespace sinks {
+
+/*!
+ * \brief Blocking strategy for handling log record queue overflows
+ *
+ * This strategy will cause enqueueing threads to block when the
+ * log record queue overflows. The blocked threads will be woken as
+ * soon as there appears free space in the queue, in the same order
+ * they attempted to enqueue records.
+ */
+class block_on_overflow
+{
+#ifndef BOOST_LOG_DOXYGEN_PASS
+private:
+    typedef intrusive::list_base_hook<
+        intrusive::link_mode< intrusive::auto_unlink >
+    > thread_context_hook_t;
+
+    struct thread_context :
+        public thread_context_hook_t
+    {
+        condition_variable cond;
+        bool result;
+
+        thread_context() : result(true) {}
+    };
+
+    typedef intrusive::list<
+        thread_context,
+        intrusive::base_hook< thread_context_hook_t >,
+        intrusive::constant_time_size< false >
+    > thread_contexts;
+
+private:
+    //! Blocked threads
+    thread_contexts m_thread_contexts;
+
+private:
+    //  Copying prohibited
+    block_on_overflow(block_on_overflow const&);
+    block_on_overflow& operator= (block_on_overflow const&);
+
+public:
+    /*!
+     * Default constructor.
+     */
+    block_on_overflow() {}
+
+    /*!
+     * This method is called by the queue when overflow is detected.
+     *
+     * \param lock An internal lock that protects the queue
+     *
+     * \retval true Attempt to enqueue the record again.
+     * \retval false Discard the record.
+     */
+    template< typename LockT >
+    bool on_overflow(record_view const&, LockT& lock)
+    {
+        thread_context context;
+        m_thread_contexts.push_back(context);
+        do
+        {
+            context.cond.wait(lock);
+        }
+        while (context.is_linked());
+
+        return context.result;
+    }
+
+    /*!
+     * This method is called by the queue when there appears a free space.
+     * The internal lock protecting the queue is locked when calling this method.
+     */
+    void on_queue_space_available()
+    {
+        if (!m_thread_contexts.empty())
+        {
+            m_thread_contexts.front().cond.notify_one();
+            m_thread_contexts.pop_front();
+        }
+    }
+
+    /*!
+     * This method is called by the queue to interrupt any possible waits in \c on_overflow.
+     * The internal lock protecting the queue is locked when calling this method.
+     */
+    void interrupt()
+    {
+        while (!m_thread_contexts.empty())
+        {
+            thread_context& context = m_thread_contexts.front();
+            context.result = false;
+            context.cond.notify_one();
+            m_thread_contexts.pop_front();
+        }
+    }
+#endif // BOOST_LOG_DOXYGEN_PASS
+};
+
+} // namespace sinks
+
+BOOST_LOG_CLOSE_NAMESPACE // namespace log
+
+} // namespace boost
+
+#include <boost/log/detail/footer.hpp>
+
+#endif // BOOST_LOG_SINKS_BLOCK_ON_OVERFLOW_HPP_INCLUDED_