premiere-libtorrent/src/create_torrent.cpp

/*

Copyright (c) 2008, 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/create_torrent.hpp"
#include "libtorrent/file_pool.hpp"
#include "libtorrent/storage.hpp"

#include <boost/date_time/posix_time/posix_time.hpp>
#include <boost/date_time/gregorian/gregorian.hpp>
#include <boost/bind.hpp>

#ifndef TORRENT_WINDOWS
#include <sys/types.h>
#include <sys/stat.h>
#endif

namespace gr = boost::gregorian;

namespace libtorrent
{
	namespace detail
	{
		int TORRENT_EXPORT get_file_attributes(boost::filesystem::path const& p)
		{
#ifdef TORRENT_WINDOWS

#ifdef TORRENT_USE_WPATH
			std::wstring path = convert_to_wstring(p.external_file_string());
#else
			std::string path = utf8_native(p.external_file_string());
#endif
			DWORD attr = GetFileAttributes(path.c_str());
			if (attr & FILE_ATTRIBUTE_HIDDEN) return file_storage::attribute_hidden;
			return 0;
#else
			struct stat s;
			if (stat(p.external_file_string().c_str(), &s) < 0) return 0;
			return (s.st_mode & S_IXUSR) ? file_storage::attribute_executable : 0;
#endif
		}
	
		int TORRENT_EXPORT get_file_attributes(boost::filesystem::wpath const& p)
		{
#ifdef TORRENT_WINDOWS
			std::wstring const& path = p.external_file_string();
			DWORD attr = GetFileAttributes(path.c_str());
			if (attr & FILE_ATTRIBUTE_HIDDEN) return file_storage::attribute_hidden;
			return 0;
#else
			std::string utf8;
			wchar_utf8(p.string(), utf8);
			struct stat s;
			if (stat(utf8.c_str(), &s) < 0) return 0;
			return (s.st_mode & S_IXUSR) ? file_storage::attribute_executable : 0;
#endif
		}
	}

	create_torrent::create_torrent(file_storage& fs, int piece_size, int pad_file_limit, int flags)
		: m_files(fs)
		, m_creation_date(pt::second_clock::universal_time())
		, m_multifile(fs.num_files() > 1)
		, m_private(false)
		, m_merkle_torrent(flags & merkle)
	{
		TORRENT_ASSERT(fs.num_files() > 0);
#if BOOST_VERSION < 103600
		if (!m_multifile && m_files.at(0).path.has_branch_path()) m_multifile = true;
#else
		if (!m_multifile && m_files.at(0).path.has_parent_path()) m_multifile = true;
#endif

		// a piece_size of 0 means automatic
		if (piece_size == 0 && !m_merkle_torrent)
		{
			const int target_size = 40 * 1024;
			piece_size = fs.total_size() / (target_size / 20);
	
			int i = 16*1024;
			for (; i < 2*1024*1024; i *= 2)
			{
				if (piece_size > i) continue;
				break;
			}
			piece_size = i;
		}
		else if (piece_size == 0 && m_merkle_torrent)
		{
			piece_size = 16*1024;
		}

		// make sure the size is an even power of 2
#ifndef NDEBUG
		for (int i = 0; i < 32; ++i)
		{
			if (piece_size & (1 << i))
			{
				TORRENT_ASSERT((piece_size & ~(1 << i)) == 0);
				break;
			}
		}
#endif
		m_files.set_piece_length(piece_size);
		if (flags & optimize)
			m_files.optimize(pad_file_limit);
		m_files.set_num_pieces(static_cast<int>(
			(m_files.total_size() + m_files.piece_length() - 1) / m_files.piece_length()));
		m_piece_hash.resize(m_files.num_pieces());
	}

	create_torrent::create_torrent(torrent_info const& ti)
		: m_files(const_cast<file_storage&>(ti.files()))
		, m_creation_date(pt::second_clock::universal_time())
		, m_multifile(ti.num_files() > 1)
		, m_private(ti.priv())
		, m_merkle_torrent(ti.is_merkle_torrent())
	{
		TORRENT_ASSERT(ti.is_valid());
		if (ti.creation_date()) m_creation_date = *ti.creation_date();

		if (!ti.creator().empty()) set_creator(ti.creator().c_str());
		if (!ti.comment().empty()) set_comment(ti.comment().c_str());

		torrent_info::nodes_t const& nodes = ti.nodes();
		for (torrent_info::nodes_t::const_iterator i = nodes.begin()
			, end(nodes.end()); i != end; ++i)
			add_node(*i);

		std::vector<libtorrent::announce_entry> const& trackers = ti.trackers();
		for (std::vector<libtorrent::announce_entry>::const_iterator i = trackers.begin()
			, end(trackers.end()); i != end; ++i)
			add_tracker(i->url, i->tier);

		std::vector<std::string> const& web_seeds = ti.url_seeds();
		for (std::vector<std::string>::const_iterator i = web_seeds.begin()
			, end(web_seeds.end()); i != end; ++i)
			add_url_seed(*i);

		m_piece_hash.resize(m_files.num_pieces());
		for (int i = 0; i < num_pieces(); ++i) set_hash(i, ti.hash_for_piece(i));

		m_info_dict = bdecode(&ti.metadata()[0], &ti.metadata()[0] + ti.metadata_size());
		m_info_hash = ti.info_hash();
	}

	entry create_torrent::generate() const
	{
		TORRENT_ASSERT(m_files.piece_length() > 0);

		entry dict;

		if (m_files.num_files() == 0)
			return dict;

		if (!m_urls.empty()) dict["announce"] = m_urls.front().first;
		
		if (!m_nodes.empty())
		{
			entry& nodes = dict["nodes"];
			entry::list_type& nodes_list = nodes.list();
			for (nodes_t::const_iterator i = m_nodes.begin()
				, end(m_nodes.end()); i != end; ++i)
			{
				entry::list_type node;
				node.push_back(entry(i->first));
				node.push_back(entry(i->second));
				nodes_list.push_back(entry(node));
			}
		}

		if (m_urls.size() > 1)
		{
			entry trackers(entry::list_t);
			entry tier(entry::list_t);
			int current_tier = m_urls.front().second;
			for (std::vector<announce_entry>::const_iterator i = m_urls.begin();
				i != m_urls.end(); ++i)
			{
				if (i->second != current_tier)
				{
					current_tier = i->second;
					trackers.list().push_back(tier);
					tier.list().clear();
				}
				tier.list().push_back(entry(i->first));
			}
			trackers.list().push_back(tier);
			dict["announce-list"] = trackers;
		}

		if (!m_comment.empty())
			dict["comment"] = m_comment;

		dict["creation date"] =
			(m_creation_date - pt::ptime(gr::date(1970, gr::Jan, 1))).total_seconds();

		if (!m_created_by.empty())
			dict["created by"] = m_created_by;
			
		if (!m_url_seeds.empty())
		{
			if (m_url_seeds.size() == 1)
			{
				dict["url-list"] = m_url_seeds.front();
			}
			else
			{
				entry& list = dict["url-list"];
				for (std::vector<std::string>::const_iterator i
					= m_url_seeds.begin(); i != m_url_seeds.end(); ++i)
				{
					list.list().push_back(entry(*i));
				}
			}
		}

		entry& info = dict["info"];
		if (m_info_dict.type() == entry::dictionary_t)
		{
			info = m_info_dict;
			return dict;
		}

		info["name"] = m_files.name();

		if (m_private) info["private"] = 1;

		if (!m_multifile)
		{
			info["length"] = m_files.at(0).size;
		}
		else
		{
			if (!info.find_key("files"))
			{
				entry& files = info["files"];

				for (file_storage::iterator i = m_files.begin();
					i != m_files.end(); ++i)
				{
					files.list().push_back(entry());
					entry& file_e = files.list().back();
					file_e["length"] = i->size;
					entry& path_e = file_e["path"];

#if BOOST_VERSION < 103600
					TORRENT_ASSERT(i->path.has_branch_path());
#else
					TORRENT_ASSERT(i->path.has_parent_path());
#endif
					TORRENT_ASSERT(*i->path.begin() == m_files.name());

					for (fs::path::iterator j = boost::next(i->path.begin());
						j != i->path.end(); ++j)
					{
						path_e.list().push_back(entry(*j));
					}
					if (i->pad_file || i->hidden_attribute || i->executable_attribute)
					{
						std::string& attr = file_e["attr"].string();
						if (i->pad_file) attr += 'p';
						if (i->hidden_attribute) attr += 'h';
						if (i->executable_attribute) attr += 'x';
					}
				}
			}
		}

		info["piece length"] = m_files.piece_length();
		if (m_merkle_torrent)
		{
			std::vector<sha1_hash> merkle_tree;
			
			// defined in torrent_info.cpp
			int merkle_num_leafs(int);
			int merkle_num_nodes(int);
			int merkle_get_parent(int);
			int merkle_get_sibling(int);

			int num_leafs = merkle_num_leafs(m_files.num_pieces());
			int num_nodes = merkle_num_nodes(num_leafs);
			int first_leaf = num_nodes - num_leafs;
			merkle_tree.resize(num_nodes);
			int num_pieces = m_piece_hash.size();
			for (int i = 0; i < num_pieces; ++i)
				merkle_tree[first_leaf + i] = m_piece_hash[i];
			sha1_hash filler(0);
			for (int i = num_pieces; i < num_leafs; ++i)
				merkle_tree[first_leaf + i] = filler;

			// now that we have initialized all leaves, build
			// each level bottom-up
			int level_start = first_leaf;
			int level_size = num_leafs;
			while (level_start > 0)
			{
				int parent = merkle_get_parent(level_start);
				for (int i = level_start; i < level_start + level_size; i += 2, ++parent)
				{
					hasher h;
					h.update((char const*)&merkle_tree[i][0], 20);
					h.update((char const*)&merkle_tree[i+1][0], 20);
					merkle_tree[parent] = h.final();
				}
				level_start = merkle_get_parent(level_start);
				level_size /= 2;
			}
			TORRENT_ASSERT(level_size == 1);
			std::string& p = info["root hash"].string();
			p.assign((char const*)&merkle_tree[0][0], 20);
		}
		else
		{
			std::string& p = info["pieces"].string();

			for (std::vector<sha1_hash>::const_iterator i = m_piece_hash.begin();
				i != m_piece_hash.end(); ++i)
			{
				p.append((char*)i->begin(), (char*)i->end());
			}
		}

		std::vector<char> buf;
		bencode(std::back_inserter(buf), info);
		m_info_hash = hasher(&buf[0], buf.size()).final();

		return dict;
	
	}

	void create_torrent::add_tracker(std::string const& url, int tier)
	{
		m_urls.push_back(announce_entry(url, tier));

		using boost::bind;
		std::sort(m_urls.begin(), m_urls.end()
			, bind(&announce_entry::second, _1) < bind(&announce_entry::second, _2));
	}

	void create_torrent::set_hash(int index, sha1_hash const& h)
	{
		TORRENT_ASSERT(index >= 0);
		TORRENT_ASSERT(index < (int)m_piece_hash.size());
		m_piece_hash[index] = h;
	}

	void create_torrent::add_node(std::pair<std::string, int> const& node)
	{
		m_nodes.push_back(node);
	}

	void create_torrent::add_url_seed(std::string const& url)
	{
		m_url_seeds.push_back(url);
	}

	void create_torrent::set_comment(char const* str)
	{
		m_comment = str;
	}

	void create_torrent::set_creator(char const* str)
	{
		m_created_by = str;
	}

}