[pacman-dev] [PATCH] alpm: Fix wrong xferred/total sizes when resuming downloads

[Olivier Brunel]

When a package is already partially downloaded in the cache, its download
size will only be of what's left to be downloaded. Since pkg->download_size
is what's used when calculating the total download size for the totaldl
callback, same thing apply.

However, the download progress callback was including this initial size,
which would thus lead to invalid values (and percentage) used in frontends.
That is, the progress bar could e.g. go further than 100%

In the case of pacman, there is a sanity check for different historical
reason (44a57c89), so before the possible "overflow" was noticed, the total
download size/progress reported was wrong. Once caught, the TotalDownload
option was ignored and it would use individual file download values as
fallback instead.

Signed-off-by: Olivier Brunel <jjk at jjacky.com>
---
Including the initial size during the dl progress cb was added in 283bf7e8,
which clearly states the goal of having the progress bar bumped when resuming a
download.

I'm not sure if this is really the best thing to do anyway though, since the
download size announced by pacman prior is that of what's left to be downloaded
only, but the progress bar is then of the package size instead, which is a bit
wrong/misleading, not to mention totally bogus when it comes to TotalDownload,
since the package size might be greater than the actual total download size.

With this fix, the progress bar will simply go from 0% to 100% and only refer to
the download size, and everything remains correct with TotalDownload.


 lib/libalpm/dload.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/libalpm/dload.c b/lib/libalpm/dload.c
index 88ea427..3e72bd4 100644
--- a/lib/libalpm/dload.c
+++ b/lib/libalpm/dload.c
@@ -131,7 +131,9 @@ static int dload_progress_cb(void *file, double dltotal, double dlnow,
 		payload->handle->dlcb(payload->remote_name, 0, (off_t)dltotal);
 	}
 
-	payload->handle->dlcb(payload->remote_name, current_size, total_size);
+	/* do NOT include initial_size since it wasn't part of the package's
+	 * download_size (nor included in the total download size callback) */
+	payload->handle->dlcb(payload->remote_name, (off_t)dlnow, (off_t)dltotal);
 
 	payload->prevprogress = current_size;
 
-- 
2.0.3