webapp: Progess bar fixes for many types of special remotes.

There was confusion in different parts of the progress bar code about
whether an update contained the total number of bytes transferred, or the
number of bytes transferred since the last update. One way this bug
showed up was progress bars that seemed to stick at zero for a long time.
In order to fix it comprehensively, I add a new BytesProcessed data type,
that is explicitly a total quantity of bytes, not a delta.

Note that this doesn't necessarily fix every problem with progress bars.
Particularly, buffering can now cause progress bars to seem to run ahead
of transfers, reaching 100% when data is still being uploaded.

Utility/Rsync.hs

@@ -8,6 +8,7 @@
 module Utility.Rsync where
 
 import Common
+import Utility.Metered
 
 import Data.Char
 
@@ -44,14 +45,13 @@ rsyncServerParams =
 rsync :: [CommandParam] -> IO Bool
 rsync = boolSystem "rsync"
 
-{- Runs rsync, but intercepts its progress output and feeds bytes
- - complete values into the callback. The progress output is also output
- - to stdout. 
+{- Runs rsync, but intercepts its progress output and updates a meter.
+ - The progress output is also output to stdout. 
  -
  - The params must enable rsync's --progress mode for this to work.
  -}
-rsyncProgress :: (Integer -> IO ()) -> [CommandParam] -> IO Bool
-rsyncProgress callback params = do
+rsyncProgress :: MeterUpdate -> [CommandParam] -> IO Bool
+rsyncProgress meterupdate params = do
 	r <- withHandle StdoutHandle createProcessSuccess p (feedprogress 0 [])
 	{- For an unknown reason, piping rsync's output like this does
 	 - causes it to run a second ssh process, which it neglects to wait
@@ -72,7 +72,7 @@ rsyncProgress callback params = do
 					Nothing -> feedprogress prev buf' h
 					(Just bytes) -> do
 						when (bytes /= prev) $
-							callback bytes
+							meterupdate $ toBytesProcessed bytes
 						feedprogress bytes buf' h
 
 {- Checks if an rsync url involves the remote shell (ssh or rsh).