fixed move_stororage to handle the case where it fails

ChangeLog

@@ -44,6 +44,8 @@ release 0.14.4
 	  (should mean a slight performance improvement)
 	* fixed a bug where a failed rename_file() would leave the storage
 	  in an error state which would pause the torrent
+	* fixed case when move_storage() would fail. Added a new alert
+	  to be posted when it does
 
 release 0.14.3
 

docs/manual.rst

@@ -2002,7 +2002,8 @@ drop while copying the file.
 
 Since disk IO is performed in a separate thread, this operation is also asynchronous.
 Once the operation completes, the ``storage_moved_alert`` is generated, with the new
-path as the message.
+path as the message. If the move fails for some reason, ``storage_moved_failed_alert``
+is generated instead, containing the error message.
 
 rename_file()
 -------------
@@ -4974,6 +4975,21 @@ the storage.
 	};
 
 
+storage_moved_failed_alert
+--------------------------
+
+The ``storage_moved_failed_alert`` is generated when an attempt to move the storage
+(via torrent_handle::move_storage()) fails.
+
+::
+
+	struct storage_moved_failed_alert: torrent_alert
+	{
+		// ...
+		error_code error;
+	};
+
+
 torrent_paused_alert
 --------------------
 

include/libtorrent/alert_types.hpp

@@ -773,6 +773,27 @@ namespace libtorrent
 		}
 	};
 
+	struct TORRENT_EXPORT storage_moved_failed_alert: torrent_alert
+	{
+		storage_moved_failed_alert(torrent_handle const& h, error_code const& ec_)
+			: torrent_alert(h)
+			, error(ec_)
+		{}
+	
+		error_code error;
+
+		virtual std::auto_ptr<alert> clone() const
+		{ return std::auto_ptr<alert>(new storage_moved_failed_alert(*this)); }
+		virtual char const* what() const { return "storage moved failed"; }
+		const static int static_category = alert::storage_notification;
+		virtual int category() const { return static_category; }
+		virtual std::string message() const
+		{
+			return torrent_alert::message() + " storage move failed: "
+				+ error.message();
+		}
+	};
+
 	struct TORRENT_EXPORT torrent_deleted_alert: torrent_alert
 	{
 		torrent_deleted_alert(torrent_handle const& h)

src/torrent.cpp

@@ -4123,6 +4123,10 @@ namespace libtorrent
 		else
 		{
 			m_save_path = save_path;
+			if (alerts().should_post<storage_moved_alert>())
+			{
+				alerts().post_alert(storage_moved_alert(get_handle(), m_save_path.string()));
+			}
 		}
 	}
 
@@ -4130,11 +4134,21 @@ namespace libtorrent
 	{
 		session_impl::mutex_t::scoped_lock l(m_ses.m_mutex);
 
-		if (alerts().should_post<storage_moved_alert>())
+		if (ret == 0)
 		{
-			alerts().post_alert(storage_moved_alert(get_handle(), j.str));
+			if (alerts().should_post<storage_moved_alert>())
+			{
+				alerts().post_alert(storage_moved_alert(get_handle(), j.str));
+			}
+			m_save_path = j.str;
+		}
+		else
+		{
+			if (alerts().should_post<storage_moved_failed_alert>())
+			{
+				alerts().post_alert(storage_moved_failed_alert(get_handle(), j.error));
+			}
 		}
-		m_save_path = j.str;
 	}
 
 	piece_manager& torrent::filesystem()