added add_piece() to inject data from external sources

ChangeLog

@@ -1,4 +1,5 @@
 
+	* added add_piece() function to inject data from external sources
 	* add_tracker() function added to torrent_handle
 	* if there is no working tracker, current_tracker is the
 	  tracker that is currently being tried

docs/manual.rst

@@ -1717,6 +1717,9 @@ Its declaration looks like this::
 		void rename_file(int index, boost::filesystem::wpath) const;
 		storage_interface* get_storage_impl() const;
 
+		enum flags_t { overwrite_existing = 1 };
+		void add_piece(int piece, char const* data, int flags = 0) const;
+
 		sha1_hash info_hash() const;
 
 		bool operator==(torrent_handle const&) const;
@@ -1868,6 +1871,27 @@ get_storage_impl()
 Returns the storage implementation for this torrent. This depends on the
 storage contructor function that was passed to ``session::add_torrent``.
 
+add_piece()
+-----------
+
+	::
+
+		enum flags_t { overwrite_existing = 1 };
+		void add_piece(int piece, char const* data, int flags = 0) const;
+
+This function will write ``data`` to the storage as piece ``piece``, as if it had
+been downloaded from a peer. ``data`` is expected to point to a buffer of as many
+bytes as the size of the specified piece. The data in the buffer is copied and
+passed on to the disk IO thread to be written at a later point.
+
+By default, data that's already been downloaded is not overwritten by this buffer. If
+you trust this data to be correct (and pass the piece hash check) you may pass the
+``overwrite_existing`` flag. This will instruct libtorrent to overwrite any data that
+may already have been downloaded with this data.
+
+Since the data is written asynchronously, you may know that is passed or failed the
+hash check by waiting for ``piece_finished_alert`` or ``has_failed_alert``.
+
 force_reannounce()
 ------------------
 

include/libtorrent/torrent.hpp

@@ -169,6 +169,11 @@ namespace libtorrent
 
 		int seed_rank(session_settings const& s) const;
 
+		enum flags_t { overwrite_existing = 1 };
+		void add_piece(int piece, char const* data, int flags = 0);
+		void on_disk_write_complete(int ret, disk_io_job const& j
+			, peer_request p);
+
 		storage_mode_t storage_mode() const { return m_storage_mode; }
 		storage_interface* get_storage()
 		{

include/libtorrent/torrent_handle.hpp

@@ -314,6 +314,9 @@ namespace libtorrent
 
 		torrent_handle() {}
 
+		enum flags_t { overwrite_existing = 1 };
+		void add_piece(int piece, char const* data, int flags = 0) const;
+
 		void get_full_peer_list(std::vector<peer_list_entry>& v) const;
 		void get_peer_info(std::vector<peer_info>& v) const;
 		torrent_status status() const;

src/torrent.cpp

@@ -371,6 +371,71 @@ namespace libtorrent
 			disconnect_all();
 	}
 	
+	void torrent::add_piece(int piece, char const* data, int flags)
+	{
+		TORRENT_ASSERT(piece >= 0 && piece < m_torrent_file->num_pieces());
+		int piece_size = m_torrent_file->piece_size(piece);
+		int blocks_in_piece = (piece_size + m_block_size - 1) / m_block_size;
+
+		peer_request p;
+		p.piece = piece;
+		p.start = 0;
+		picker().inc_refcount(piece);
+		for (int i = 0; i < blocks_in_piece; ++i, p.start += m_block_size)
+		{
+			if (picker().is_finished(piece_block(piece, i))
+				&& (flags & torrent::overwrite_existing) == 0)
+				continue;
+
+			p.length = (std::min)(piece_size - p.start, m_block_size);
+			char* buffer = m_ses.allocate_disk_buffer();
+			// out of memory
+			if (buffer == 0) return;
+			disk_buffer_holder holder(m_ses, buffer);
+			std::memcpy(buffer, data + p.start, p.length);
+			filesystem().async_write(p, holder, bind(&torrent::on_disk_write_complete
+				, shared_from_this(), _1, _2, p));
+			piece_block block(piece, i);
+			picker().mark_as_downloading(block, 0, piece_picker::fast);
+			picker().mark_as_writing(block, 0);
+		}
+		picker().dec_refcount(piece);
+	}
+
+	void torrent::on_disk_write_complete(int ret, disk_io_job const& j
+		, peer_request p)
+	{
+		session_impl::mutex_t::scoped_lock l(m_ses.m_mutex);
+
+		INVARIANT_CHECK;
+	
+		if (m_abort)
+		{
+			piece_block block_finished(p.piece, p.start / m_block_size);
+			return;
+		}
+
+		piece_block block_finished(p.piece, p.start / m_block_size);
+
+		if (ret == -1)
+		{
+			if (has_picker()) picker().write_failed(block_finished);
+			if (alerts().should_post<file_error_alert>())
+				alerts().post_alert(file_error_alert(j.error_file, get_handle(), j.str));
+			set_error(j.str);
+			pause();
+			return;
+		}
+		picker().mark_as_finished(block_finished, 0);
+
+		// did we just finish the piece?
+		if (picker().is_piece_finished(p.piece))
+		{
+			async_verify_piece(p.piece, bind(&torrent::piece_finished, shared_from_this()
+				, p.piece, _1));
+		}
+	}
+
 	peer_request torrent::to_req(piece_block const& p)
 	{
 		int block_offset = p.block_index * m_block_size;

src/torrent_handle.cpp

@@ -535,6 +535,12 @@ namespace libtorrent
 		TORRENT_FORWARD(add_tracker(url));
 	}
 
+	void torrent_handle::add_piece(int piece, char const* data, int flags) const
+	{
+		INVARIANT_CHECK;
+		TORRENT_FORWARD(add_piece(piece, data, flags));
+	}
+
 	storage_interface* torrent_handle::get_storage_impl() const
 	{
 		INVARIANT_CHECK;

test/test_torrent.cpp

@@ -49,11 +49,28 @@ void test_running_torrent(boost::intrusive_ptr<torrent_info> info, size_type fil
 	TEST_CHECK(st.total_wanted == file_size);
 	std::cout << "total_wanted_done: " << st.total_wanted_done << " : 0" << std::endl;
 	TEST_CHECK(st.total_wanted_done == 0);
+
+	if (info->num_pieces() > 0)
+	{
+		h.piece_priority(0, 1);
+		st = h.status();
+		TEST_CHECK(st.pieces[0] == false);
+		std::vector<char> piece(info->piece_length());
+		for (int i = 0; i < int(piece.size()); ++i)
+			piece[i] = (i % 26) + 'A';
+		h.add_piece(0, &piece[0]);
+		test_sleep(10000);
+		st = h.status();
+		TEST_CHECK(st.pieces[0] == true);
+	}
 }
 
 int test_main()
 {
 	{
+		remove("test_torrent_dir2/tmp1");
+		remove("test_torrent_dir2/tmp2");
+		remove("test_torrent_dir2/tmp3");
 		file_storage fs;
 		size_type file_size = 1 * 1024 * 1024 * 1024;
 		fs.add_file("test_torrent_dir2/tmp1", file_size);
@@ -69,6 +86,7 @@ int test_main()
 		// calculate the hash for all pieces
 		sha1_hash ph = hasher(&piece[0], piece.size()).final();
 		int num = t.num_pieces();
+		TEST_CHECK(t.num_pieces() > 0);
 		for (int i = 0; i < num; ++i)
 			t.set_hash(i, ph);
 
@@ -76,6 +94,7 @@ int test_main()
 		std::back_insert_iterator<std::vector<char> > out(tmp);
 		bencode(out, t.generate());
 		boost::intrusive_ptr<torrent_info> info(new torrent_info(&tmp[0], tmp.size()));
+		TEST_CHECK(info->num_pieces() > 0);
 
 		test_running_torrent(info, file_size);
 	}