fixed stale state when switching from finished to downloading

include/libtorrent/torrent.hpp

@@ -481,6 +481,11 @@ namespace libtorrent
 		// completed() is called immediately after it.
 		void finished();
 
+		// This is the opposite of finished. It is called if we used
+		// to be finished but enabled some files for download so that
+		// we wasn't finished anymore.
+		void resume_download();
+
 		void async_verify_piece(int piece_index, boost::function<void(int)> const&);
 
 		// this is called from the peer_connection

src/torrent.cpp

@@ -1653,6 +1653,8 @@ namespace libtorrent
 		// the torrent just became finished
 		if (is_finished() && !was_finished)
 			finished();
+		else if (!is_finished() && was_finished)
+			resume_download();
 	}
 
 	void torrent::filter_piece(int index, bool filter)
@@ -2964,7 +2966,7 @@ namespace libtorrent
 		{
 			peer_connection* p = *i;
 			TORRENT_ASSERT(p->associated_torrent().lock().get() == this);
-			if (p->is_seed())
+			if (p->upload_only())
 			{
 #if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_ERROR_LOGGING
 				(*p->m_logger) << "*** SEED, CLOSING CONNECTION\n";
@@ -2981,6 +2983,15 @@ namespace libtorrent
 			bind(&torrent::on_files_released, shared_from_this(), _1, _2));
 	}
 
+	// this is called when we were finished, but some files were
+	// marked for downloading, and we are no longer finished	
+	void torrent::resume_download()
+	{
+		INVARIANT_CHECK;
+	
+		m_state = torrent_status::downloading;
+	}
+
 	// called when torrent is complete (all pieces downloaded)
 	void torrent::completed()
 	{