add asynchronous overload of torrent_handle::add_piece()

ChangeLog

@@ -1,4 +1,5 @@
 
+	* add asynchronous overload of torrent_handle::add_piece()
 	* default to a single hashing thread, for full checks
 	* Fix bug when checking files and the first piece is invalid
 

include/libtorrent/torrent.hpp

@@ -462,6 +462,7 @@ namespace libtorrent {
 		int seed_rank(aux::session_settings const& s) const;
 
 		void add_piece(piece_index_t piece, char const* data, add_piece_flags_t flags);
+		void add_piece_async(piece_index_t piece, std::vector<char> data, add_piece_flags_t flags);
 		void on_disk_write_complete(storage_error const& error
 			, peer_request const& p);
 

include/libtorrent/torrent_handle.hpp

@@ -268,10 +268,7 @@ namespace aux {
 		static constexpr add_piece_flags_t overwrite_existing = 0_bit;
 
 		// 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.
+		// as if it had been downloaded from a peer.
 		//
 		// 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
@@ -285,7 +282,20 @@ namespace aux {
 		//
 		// Adding pieces while the torrent is being checked (i.e. in
 		// torrent_status::checking_files state) is not supported.
+		//
+		// The overload taking a raw pointer to the data is a blocking call. It
+		// won't return until the libtorrent thread has copied the data into its
+		// disk write buffer. ``data`` is expected to point to a buffer of as
+		// many bytes as the size of the specified piece. See
+		// file_storage::piece_size().
+		//
+		// The data in the buffer is copied and passed on to the disk IO thread
+		// to be written at a later point.
+		//
+		// The overload taking a ``std::vector<char>`` is not blocking, it will
+		// send the buffer to the main thread and return immediately.
 		void add_piece(piece_index_t piece, char const* data, add_piece_flags_t flags = {}) const;
+		void add_piece(piece_index_t piece, std::vector<char> data, add_piece_flags_t flags = {}) const;
 
 		// This function starts an asynchronous read operation of the specified
 		// piece from this torrent. You must have completed the download of the

src/torrent.cpp

@@ -1258,12 +1258,33 @@ bool is_downloading_state(int const st)
 		piece_index_t m_piece;
 	};
 
+	void torrent::add_piece_async(piece_index_t const piece
+		, std::vector<char> data, add_piece_flags_t const flags)
+	{
+		TORRENT_ASSERT(is_single_thread());
+
+		// make sure the piece index is correct
+		if (piece >= torrent_file().end_piece())
+			return;
+
+		// make sure the piece size is correct
+		if (data.size() != std::size_t(m_torrent_file->piece_size(piece)))
+			return;
+
+		add_piece(piece, data.data(), flags);
+	}
+
 	// TODO: 3 there's some duplication between this function and
 	// peer_connection::incoming_piece(). is there a way to merge something?
 	void torrent::add_piece(piece_index_t const piece, char const* data
 		, add_piece_flags_t const flags)
 	{
 		TORRENT_ASSERT(is_single_thread());
+
+		// make sure the piece index is correct
+		if (piece >= torrent_file().end_piece())
+			return;
+
 		int const piece_size = m_torrent_file->piece_size(piece);
 		int const blocks_in_piece = (piece_size + block_size() - 1) / block_size();
 

src/torrent_handle.cpp

@@ -121,7 +121,7 @@ namespace libtorrent {
 #ifndef BOOST_NO_EXCEPTIONS
 			try {
 #endif
-				(t.get()->*f)(a...);
+				(t.get()->*f)(std::move(a)...);
 #ifndef BOOST_NO_EXCEPTIONS
 			} catch (system_error const& e) {
 				ses.alerts().emplace_alert<torrent_error_alert>(torrent_handle(m_torrent)
@@ -153,7 +153,7 @@ namespace libtorrent {
 #ifndef BOOST_NO_EXCEPTIONS
 			try {
 #endif
-				(t.get()->*f)(a...);
+				(t.get()->*f)(std::move(a)...);
 #ifndef BOOST_NO_EXCEPTIONS
 			} catch (...) {
 				ex = std::current_exception();
@@ -189,7 +189,7 @@ namespace libtorrent {
 #ifndef BOOST_NO_EXCEPTIONS
 			try {
 #endif
-				r = (t.get()->*f)(a...);
+				r = (t.get()->*f)(std::move(a)...);
 #ifndef BOOST_NO_EXCEPTIONS
 			} catch (...) {
 				ex = std::current_exception();
@@ -698,6 +698,12 @@ namespace libtorrent {
 		sync_call(&torrent::add_piece, piece, data, flags);
 	}
 
+	void torrent_handle::add_piece(piece_index_t piece, std::vector<char> data
+		, add_piece_flags_t const flags) const
+	{
+		async_call(&torrent::add_piece_async, piece, std::move(data), flags);
+	}
+
 	void torrent_handle::read_piece(piece_index_t piece) const
 	{
 		async_call(&torrent::read_piece, piece);

test/test_remap_files.cpp

@@ -117,7 +117,7 @@ void test_remap_files(storage_mode_t storage_mode = storage_mode_sparse)
 	for (auto const i : fs.piece_range())
 	{
 		std::vector<char> const piece = generate_piece(i, fs.piece_size(i));
-		tor1.add_piece(i, piece.data());
+		tor1.add_piece(i, std::move(piece));
 	}
 
 	// read pieces

test/test_resume.cpp

@@ -1801,7 +1801,7 @@ TORRENT_TEST(resume_data_have_pieces)
 	atp.save_path = ".";
 	auto h = ses.add_torrent(atp);
 	wait_for_downloading(ses, "");
-	h.add_piece(0_piece, piece_data.data());
+	h.add_piece(0_piece, std::move(piece_data));
 
 	h.save_resume_data();
 	ses.pause();

test/test_torrent.cpp

@@ -875,10 +875,10 @@ TORRENT_TEST(redundant_add_piece)
 	auto h = ses.add_torrent(atp);
 	wait_for_downloading(ses, "");
 
-	h.add_piece(0_piece, piece_data.data());
+	h.add_piece(0_piece, piece_data);
 	h.set_piece_deadline(0_piece, 0, torrent_handle::alert_when_available);
 	h.prioritize_pieces(std::vector<lt::download_priority_t>(std::size_t(ti->num_pieces()), lt::dont_download));
-	h.add_piece(0_piece, piece_data.data());
+	h.add_piece(0_piece, std::move(piece_data));
 	std::this_thread::sleep_for(lt::seconds(2));
 }