/*

Copyright (c) 2012-2016, 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.

*/

#ifndef TORRENT_DISK_INTERFACE_HPP
#define TORRENT_DISK_INTERFACE_HPP

#include "libtorrent/bdecode.hpp"

#include <string>
#include <memory>

#include "libtorrent/units.hpp"
#include "libtorrent/disk_buffer_holder.hpp"
#include "libtorrent/aux_/vector.hpp"
#include "libtorrent/export.hpp"
#include "libtorrent/storage_defs.hpp"

namespace libtorrent
{
	struct storage_interface;
	struct peer_request;
	struct disk_observer;
	struct file_pool;
	struct add_torrent_params;
	struct cache_status;
	struct disk_buffer_holder;
	struct counters;
	struct settings_pack;
	struct storage_params;
	class file_storage;

	struct storage_holder;

	struct TORRENT_EXTRA_EXPORT disk_interface
	{
		enum flags_t
		{
			sequential_access = 0x1,

			// this flag is set on a job when a read operation did
			// not hit the disk, but found the data in the read cache.
			cache_hit = 0x2,

			// don't keep the read block in cache
			volatile_read = 0x10,
		};

		virtual storage_holder new_torrent(std::unique_ptr<storage_interface> storage) = 0;
		virtual void remove_torrent(storage_index_t) = 0;
		virtual storage_interface* get_torrent(storage_index_t) = 0;

		virtual void async_read(storage_index_t storage, peer_request const& r
			, std::function<void(disk_buffer_holder block, int flags, storage_error const& se)> handler
			, void* requester, std::uint8_t flags = 0) = 0;
		virtual bool async_write(storage_index_t storage, peer_request const& r
			, char const* buf, std::shared_ptr<disk_observer> o
			, std::function<void(storage_error const&)> handler
			, std::uint8_t flags = 0) = 0;
		virtual void async_hash(storage_index_t storage, piece_index_t piece, std::uint8_t flags
			, std::function<void(piece_index_t, sha1_hash const&, storage_error const&)> handler, void* requester) = 0;
		virtual void async_move_storage(storage_index_t storage, std::string const& p, std::uint8_t flags
			, std::function<void(status_t, std::string const&, storage_error const&)> handler) = 0;
		virtual void async_release_files(storage_index_t storage
			, std::function<void()> handler = std::function<void()>()) = 0;
		virtual void async_check_files(storage_index_t storage
			, add_torrent_params const* resume_data
			, aux::vector<std::string, file_index_t>& links
			, std::function<void(status_t, storage_error const&)> handler) = 0;
		virtual void async_flush_piece(storage_index_t storage, piece_index_t piece
			, std::function<void()> handler = std::function<void()>()) = 0;
		virtual void async_stop_torrent(storage_index_t storage
			, std::function<void()> handler = std::function<void()>()) = 0;
		virtual void async_rename_file(storage_index_t storage
			, file_index_t index, std::string const& name
			, std::function<void(std::string const&, file_index_t, storage_error const&)> handler) = 0;
		virtual void async_delete_files(storage_index_t storage, int options
			, std::function<void(storage_error const&)> handler) = 0;
		virtual void async_set_file_priority(storage_index_t storage
			, aux::vector<std::uint8_t, file_index_t> const& prio
			, std::function<void(storage_error const&)> handler) = 0;

		virtual void async_clear_piece(storage_index_t storage, piece_index_t index
			, std::function<void(piece_index_t)> handler) = 0;
		virtual void clear_piece(storage_index_t storage, piece_index_t index) = 0;

		virtual void update_stats_counters(counters& c) const = 0;
		virtual void get_cache_info(cache_status* ret, storage_index_t storage
			, bool no_pieces = true, bool session = true) const = 0;

		virtual file_pool& files() = 0;

#if TORRENT_USE_ASSERTS
		virtual bool is_disk_buffer(char* buffer) const = 0;
#endif
	protected:
		~disk_interface() {}
	};

	struct storage_holder
	{
		storage_holder() = default;
		storage_holder(storage_index_t idx, disk_interface& disk_io)
			: m_disk_io(&disk_io)
			, m_idx(idx)
		{}
		~storage_holder()
		{
			if (m_disk_io) m_disk_io->remove_torrent(m_idx);
		}

		explicit operator bool() const { return m_disk_io != nullptr; }

		operator storage_index_t() const
		{
			TORRENT_ASSERT(m_disk_io);
			return m_idx;
		}

		void reset()
		{
			if (m_disk_io) m_disk_io->remove_torrent(m_idx);
			m_disk_io = nullptr;
		}

		storage_holder(storage_holder const&) = delete;
		storage_holder& operator=(storage_holder const&) = delete;

		storage_holder(storage_holder&& rhs)
			: m_disk_io(rhs.m_disk_io)
			, m_idx(rhs.m_idx)
		{
				rhs.m_disk_io = nullptr;
		}

		storage_holder& operator=(storage_holder&& rhs)
		{
			if (m_disk_io) m_disk_io->remove_torrent(m_idx);
			m_disk_io = rhs.m_disk_io;
			m_idx = rhs.m_idx;
			rhs.m_disk_io = nullptr;
			return *this;
		}
	private:
		disk_interface* m_disk_io = nullptr;
		storage_index_t m_idx{0};
	};

}

#endif