Straighten up file transfer cancellation

There was a mess with fileTransferCancelled(); it was only emitted when
a download (but not an upload) was cancelled; besides, in case of
downloads a file transfer info structure was getting deleted whereas
uploads left a file transfer in Cancelled status. This all now converges
on:
- fileTransferFailed() for both failures and cancellations (to simplify
  slot connection, and also to follow the practice in, e.g., Qt Network).
- the file transfer info structure is kept around in Cancelled status,
  following the logic used for failures. There's no particular cleanup
  which may become a problem if one uploads and cancels many times
  (download file transfers are keyed to event ids, mitigating
  the problem); this will be fixed in another commit.

Closes #503. Closes #504.

1 files changed, 2 insertions, 1 deletions

diff --git a/lib/room.h b/lib/room.h
index d3a7466d..4e55dbaf 100644
--- a/lib/room.h
+++ b/lib/room.h
@@ -712,7 +712,8 @@ Q_SIGNALS:
     void fileTransferProgress(QString id, qint64 progress, qint64 total);
     void fileTransferCompleted(QString id, QUrl localFile, QUrl mxcUrl);
     void fileTransferFailed(QString id, QString errorMessage = {});
-    void fileTransferCancelled(QString id);
+    // fileTransferCancelled() is no more here; use fileTransferFailed() and
+    // check the transfer status instead
 
     void callEvent(Quotient::Room* room, const Quotient::RoomEvent* event);