merged back async_io branch into trunk

include/libtorrent/disk_io_thread.hpp

@@ -0,0 +1,119 @@
+/*
+
+Copyright (c) 2007, Arvid Norberg
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * 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.
+    * Neither the name of the author nor the names of its
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 THE COPYRIGHT OWNER 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.
+
+*/
+
+#include "libtorrent/storage.hpp"
+#include <boost/thread/thread.hpp>
+#include <boost/function.hpp>
+#include <boost/thread/mutex.hpp>
+#include <boost/bind.hpp>
+#include <boost/pool/pool.hpp>
+#include <boost/noncopyable.hpp>
+#include "libtorrent/config.hpp"
+
+namespace libtorrent
+{
+
+	struct disk_io_job
+	{
+		disk_io_job()
+			: action(read)
+			, buffer(0)
+			, buffer_size(0)
+			, piece(0)
+			, offset(0)
+		{}
+
+		enum action_t
+		{
+			read
+			, write
+			, hash
+			, move_storage
+			, release_files
+		};
+
+		action_t action;
+
+		char* buffer;
+		size_type buffer_size;
+		boost::intrusive_ptr<piece_manager> storage;
+		// arguments used for read and write
+		int piece, offset;
+		// used for move_storage. On errors, this is set
+		// to the error message
+		std::string str;
+
+		// this is called when operation completes
+		boost::function<void(int, disk_io_job const&)> callback;
+	};
+
+	// this is a singleton consisting of the thread and a queue
+	// of disk io jobs
+	struct disk_io_thread : boost::noncopyable
+	{
+		disk_io_thread(int block_size = 16 * 1024);
+		~disk_io_thread();
+
+		// aborts read operations
+		void stop(boost::intrusive_ptr<piece_manager> s);
+		void add_job(disk_io_job const& j
+			, boost::function<void(int, disk_io_job const&)> const& f
+			= boost::function<void(int, disk_io_job const&)>());
+
+		// keep track of the number of bytes in the job queue
+		// at any given time. i.e. the sum of all buffer_size.
+		// this is used to slow down the download global download
+		// speed when the queue buffer size is too big.
+		size_type queue_buffer_size() const
+		{ return m_queue_buffer_size; }
+
+		void operator()();
+
+		char* allocate_buffer();
+
+	private:
+
+		boost::mutex m_mutex;
+		boost::condition m_signal;
+		bool m_abort;
+		std::deque<disk_io_job> m_jobs;
+		size_type m_queue_buffer_size;
+
+		// memory pool for read and write operations
+		boost::pool<> m_pool;
+
+		// thread for performing blocking disk io operations
+		boost::thread m_disk_io_thread;
+	};
+
+}
+