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.

24 files changed, 172 insertions, 129 deletions

diff --git a/Command/SendKey.hs b/Command/SendKey.hs
index 3e46d9dd0..0a07dcece 100644
--- a/Command/SendKey.hs
+++ b/Command/SendKey.hs
@@ -13,6 +13,7 @@ import Annex.Content
 import Utility.Rsync
 import Logs.Transfer
 import qualified Fields
+import Utility.Metered
 
 def :: [Command]
 def = [noCommit $ command "sendkey" paramKey seek
diff --git a/Command/TransferInfo.hs b/Command/TransferInfo.hs
index aacc69bb1..4bebdebcd 100644
--- a/Command/TransferInfo.hs
+++ b/Command/TransferInfo.hs
@@ -13,6 +13,7 @@ import Annex.Content
 import Logs.Transfer
 import Types.Key
 import qualified Fields
+import Utility.Metered
 
 def :: [Command]
 def = [noCommit $ command "transferinfo" paramKey seek SectionPlumbing
@@ -50,10 +51,14 @@ start (k:[]) = do
 			(update, tfile, _) <- mkProgressUpdater t info
 			liftIO $ mapM_ void
 				[ tryIO $ forever $ do
-					bytes <- readish <$> getLine
-					maybe (error "transferinfo protocol error") update bytes
+					bytes <- readUpdate
+					maybe (error "transferinfo protocol error")
+						(update . toBytesProcessed) bytes
 				, tryIO $ removeFile tfile
 				, exitSuccess
 				]
 	stop
 start _ = error "wrong number of parameters"
+
+readUpdate :: IO (Maybe Integer)
+readUpdate = readish <$> getLine
diff --git a/Logs/Transfer.hs b/Logs/Transfer.hs
index e73933172..52ed03e5c 100644
--- a/Logs/Transfer.hs
+++ b/Logs/Transfer.hs
@@ -13,6 +13,7 @@ import Annex.Exception
 import qualified Git
 import Types.Remote
 import Types.Key
+import Utility.Metered
 import Utility.Percentage
 import Utility.QuickCheck
 
@@ -165,12 +166,13 @@ mkProgressUpdater t info = do
 	mvar <- liftIO $ newMVar 0
 	return (liftIO . updater tfile mvar, tfile, mvar)
   where
-	updater tfile mvar bytes = modifyMVar_ mvar $ \oldbytes -> do
-		if (bytes - oldbytes >= mindelta)
+	updater tfile mvar b = modifyMVar_ mvar $ \oldbytes -> do
+		let newbytes = fromBytesProcessed b
+		if (newbytes - oldbytes >= mindelta)
 			then do
-				let info' = info { bytesComplete = Just bytes }
+				let info' = info { bytesComplete = Just newbytes }
 				_ <- tryIO $ writeTransferInfoFile info' tfile
-				return bytes
+				return newbytes
 			else return oldbytes
 	{- The minimum change in bytesComplete that is worth
 	 - updating a transfer info file for is 1% of the total
diff --git a/Messages.hs b/Messages.hs
index d79c91aa0..13b786a31 100644
--- a/Messages.hs
+++ b/Messages.hs
@@ -43,14 +43,15 @@ import System.Log.Logger
 import System.Log.Formatter
 import System.Log.Handler (setFormatter, LogHandler)
 import System.Log.Handler.Simple
+import qualified Data.Set as S
 
 import Common
 import Types
 import Types.Messages
+import qualified Messages.JSON as JSON
 import Types.Key
 import qualified Annex
-import qualified Messages.JSON as JSON
-import qualified Data.Set as S
+import Utility.Metered
 
 showStart :: String -> String -> Annex ()
 showStart command file = handle (JSON.start command $ Just file) $
@@ -86,7 +87,7 @@ meteredBytes combinemeterupdate size a = withOutputType go
 		meter <- liftIO $ newMeter progress "B" 25 (renderNums binaryOpts 1)
 		showOutput
 		r <- a $ \n -> liftIO $ do
-			incrP progress n
+			setP progress $ fromBytesProcessed n
 			displayMeter stdout meter
 			maybe noop (\m -> m n) combinemeterupdate
 		liftIO $ clearMeter stdout meter
diff --git a/Meters.hs b/Meters.hs
deleted file mode 100644
index 378e570a2..000000000
--- a/Meters.hs
+++ /dev/null
@@ -1,40 +0,0 @@
-{- git-annex meters
- -
- - Copyright 2012 Joey Hess <joey@kitenet.net>
- -
- - Licensed under the GNU GPL version 3 or higher.
- -}
-
-module Meters where
-
-import Common
-import Types.Meters
-import Utility.Observed
-
-import qualified Data.ByteString.Lazy as L
-import qualified Data.ByteString as S
-
-{- Sends the content of a file to an action, updating the meter as it's
- - consumed. -}
-withMeteredFile :: FilePath -> MeterUpdate -> (L.ByteString -> IO a) -> IO a
-withMeteredFile f meterupdate a = withBinaryFile f ReadMode $ \h ->
-	hGetContentsObserved h (meterupdate . toInteger) >>= a
-
-{- Sends the content of a file to a Handle, updating the meter as it's
- - written. -}
-streamMeteredFile :: FilePath -> MeterUpdate -> Handle -> IO ()
-streamMeteredFile f meterupdate h = withMeteredFile f meterupdate $ L.hPut h
-
-{- Writes a ByteString to a Handle, updating a meter as it's written. -}
-meteredWrite :: MeterUpdate -> Handle -> L.ByteString -> IO ()
-meteredWrite meterupdate h = go . L.toChunks 
-  where
-	go [] = return ()
-	go (c:cs) = do
-		S.hPut h c
-		meterupdate $ toInteger $ S.length c
-		go cs
-
-meteredWriteFile :: MeterUpdate -> FilePath -> L.ByteString -> IO ()
-meteredWriteFile meterupdate f b = withBinaryFile f WriteMode $ \h ->
-	meteredWrite meterupdate h b
diff --git a/Remote/Bup.hs b/Remote/Bup.hs
index d168f0715..1c69d0a1c 100644
--- a/Remote/Bup.hs
+++ b/Remote/Bup.hs
@@ -29,6 +29,7 @@ import Data.ByteString.Lazy.UTF8 (fromString)
 import Data.Digest.Pure.SHA
 import Utility.UserInfo
 import Annex.Content
+import Utility.Metered
 
 type BupRepo = String
 
diff --git a/Remote/Directory.hs b/Remote/Directory.hs
index be533d038..8c5fa795e 100644
--- a/Remote/Directory.hs
+++ b/Remote/Directory.hs
@@ -24,7 +24,7 @@ import Remote.Helper.Encryptable
 import Remote.Helper.Chunked
 import Crypto
 import Annex.Content
-import Meters
+import Utility.Metered
 
 remote :: RemoteType
 remote = RemoteType {
@@ -154,17 +154,20 @@ storeSplit' :: MeterUpdate -> Int64 -> [FilePath] -> [S.ByteString] -> [FilePath
 storeSplit' _ _ [] _ _ = error "ran out of dests"
 storeSplit' _ _  _ [] c = return $ reverse c
 storeSplit' meterupdate chunksize (d:dests) bs c = do
-	bs' <- E.bracket (openFile d WriteMode) hClose (feed chunksize bs)
+	bs' <- E.bracket (openFile d WriteMode) hClose $
+		feed zeroBytesProcessed chunksize bs
 	storeSplit' meterupdate chunksize dests bs' (d:c)
   where
-	feed _ [] _ = return []
-	feed sz (l:ls) h = do
-		let s = fromIntegral $ S.length l
+	feed _ _ [] _ = return []
+	feed bytes sz (l:ls) h = do
+		let len = S.length l
+		let s = fromIntegral len
 		if s <= sz || sz == chunksize
 			then do
 				S.hPut h l
-				meterupdate $ toInteger s
-				feed (sz - s) ls h
+				let bytes' = addBytesProcessed bytes len
+				meterupdate bytes'
+				feed bytes' (sz - s) ls h
 			else return (l:ls)
 
 storeHelper :: FilePath -> ChunkSize -> Key -> ([FilePath] -> IO [FilePath]) -> Annex Bool
diff --git a/Remote/Git.hs b/Remote/Git.hs
index 207655b4e..31396003b 100644
--- a/Remote/Git.hs
+++ b/Remote/Git.hs
@@ -40,6 +40,7 @@ import Init
 import Types.Key
 import qualified Fields
 import Logs.Location
+import Utility.Metered
 
 import Control.Concurrent
 import Control.Concurrent.MSampleVar
@@ -309,7 +310,7 @@ copyFromRemote r key file dest
 			: maybe [] (\f -> [(Fields.associatedFile, f)]) file
 		Just (cmd, params) <- git_annex_shell (repo r) "transferinfo" 
 			[Param $ key2file key] fields
-		v <- liftIO $ newEmptySV
+		v <- liftIO $ (newEmptySV :: IO (MSampleVar Integer))
 		tid <- liftIO $ forkIO $ void $ tryIO $ do
 			bytes <- readSV v
 			p <- createProcess $
@@ -325,7 +326,7 @@ copyFromRemote r key file dest
 			send bytes
 			forever $
 				send =<< readSV v
-		let feeder = writeSV v
+		let feeder = writeSV v . fromBytesProcessed
 		bracketIO noop (const $ tryIO $ killThread tid) (a feeder)
 
 copyFromRemoteCheap :: Remote -> Key -> FilePath -> Annex Bool
@@ -391,13 +392,13 @@ rsyncOrCopyFile rsyncparams src dest p =
 	dorsync = rsyncHelper (Just p) $
 		rsyncparams ++ [Param src, Param dest]
 	docopy = liftIO $ bracket
-		(forkIO $ watchfilesize 0)
+		(forkIO $ watchfilesize zeroBytesProcessed)
 		(void . tryIO . killThread)
 		(const $ copyFileExternal src dest)
 	watchfilesize oldsz = do
 		threadDelay 500000 -- 0.5 seconds
 		v <- catchMaybeIO $
-			fromIntegral . fileSize
+			toBytesProcessed . fileSize
 				<$> getFileStatus dest
 		case v of
 			Just sz
diff --git a/Remote/Glacier.hs b/Remote/Glacier.hs
index ea5df31e5..088c62fb3 100644
--- a/Remote/Glacier.hs
+++ b/Remote/Glacier.hs
@@ -22,7 +22,7 @@ import Remote.Helper.Encryptable
 import qualified Remote.Helper.AWS as AWS
 import Crypto
 import Creds
-import Meters
+import Utility.Metered
 import qualified Annex
 import Annex.Content
 
diff --git a/Remote/Helper/Chunked.hs b/Remote/Helper/Chunked.hs
index 11b86042e..46678de70 100644
--- a/Remote/Helper/Chunked.hs
+++ b/Remote/Helper/Chunked.hs
@@ -10,7 +10,7 @@ module Remote.Helper.Chunked where
 import Common.Annex
 import Utility.DataUnits
 import Types.Remote
-import Meters
+import Utility.Metered
 
 import qualified Data.Map as M
 import qualified Data.ByteString.Lazy as L
diff --git a/Remote/Helper/Encryptable.hs b/Remote/Helper/Encryptable.hs
index 242fcfe8a..4f0404f2a 100644
--- a/Remote/Helper/Encryptable.hs
+++ b/Remote/Helper/Encryptable.hs
@@ -15,6 +15,7 @@ import Crypto
 import qualified Annex
 import Config.Cost
 import Utility.Base64
+import Utility.Metered
 
 {- Encryption setup for a remote. The user must specify whether to use
  - an encryption key, or not encrypt. An encrypted cipher is created, or is
diff --git a/Remote/Hook.hs b/Remote/Hook.hs
index 97691d075..46ee8000f 100644
--- a/Remote/Hook.hs
+++ b/Remote/Hook.hs
@@ -21,6 +21,7 @@ import Annex.Content
 import Remote.Helper.Special
 import Remote.Helper.Encryptable
 import Crypto
+import Utility.Metered
 
 remote :: RemoteType
 remote = RemoteType {
diff --git a/Remote/Rsync.hs b/Remote/Rsync.hs
index 1425601ad..9563b43e8 100644
--- a/Remote/Rsync.hs
+++ b/Remote/Rsync.hs
@@ -22,6 +22,7 @@ import Remote.Helper.Encryptable
 import Crypto
 import Utility.Rsync
 import Utility.CopyFile
+import Utility.Metered
 import Annex.Perms
 
 type RsyncUrl = String
diff --git a/Remote/S3.hs b/Remote/S3.hs
index 0ca86f1ff..017886694 100644
--- a/Remote/S3.hs
+++ b/Remote/S3.hs
@@ -27,7 +27,7 @@ import Remote.Helper.Encryptable
 import qualified Remote.Helper.AWS as AWS
 import Crypto
 import Creds
-import Meters
+import Utility.Metered
 import Annex.Content
 
 remote :: RemoteType
diff --git a/Remote/Web.hs b/Remote/Web.hs
index b0d12002c..5af3c5228 100644
--- a/Remote/Web.hs
+++ b/Remote/Web.hs
@@ -17,6 +17,7 @@ import Config.Cost
 import Logs.Web
 import qualified Utility.Url as Url
 import Types.Key
+import Utility.Metered
 
 import qualified Data.Map as M
 
diff --git a/Remote/WebDAV.hs b/Remote/WebDAV.hs
index 3b729fe83..db5535494 100644
--- a/Remote/WebDAV.hs
+++ b/Remote/WebDAV.hs
@@ -30,7 +30,7 @@ import Remote.Helper.Encryptable
 import Remote.Helper.Chunked
 import Crypto
 import Creds
-import Meters
+import Utility.Metered
 import Annex.Content
 
 type DavUrl = String
diff --git a/Types.hs b/Types.hs
index d19ac3de1..ea0fa6b89 100644
--- a/Types.hs
+++ b/Types.hs
@@ -14,8 +14,7 @@ module Types (
 	RemoteGitConfig(..),
 	Remote,
 	RemoteType,
-	Option,
-	MeterUpdate
+	Option
 ) where
 
 import Annex
@@ -25,7 +24,6 @@ import Types.Key
 import Types.UUID
 import Types.Remote
 import Types.Option
-import Types.Meters
 
 type Backend = BackendA Annex
 type Remote = RemoteA Annex
diff --git a/Types/Meters.hs b/Types/Meters.hs
deleted file mode 100644
index ef304d1ae..000000000
--- a/Types/Meters.hs
+++ /dev/null
@@ -1,12 +0,0 @@
-{- git-annex meter types
- -
- - Copyright 2012 Joey Hess <joey@kitenet.net>
- -
- - Licensed under the GNU GPL version 3 or higher.
- -}
-
-module Types.Meters where
-
-{- An action that can be run repeatedly, feeding it the number of
- - bytes sent or retrieved so far. -}
-type MeterUpdate = (Integer -> IO ())
diff --git a/Types/Remote.hs b/Types/Remote.hs
index 64a77109c..e6536757c 100644
--- a/Types/Remote.hs
+++ b/Types/Remote.hs
@@ -15,9 +15,9 @@ import Data.Ord
 import qualified Git
 import Types.Key
 import Types.UUID
-import Types.Meters
 import Types.GitConfig
 import Config.Cost
+import Utility.Metered
 
 type RemoteConfigKey = String
 type RemoteConfig = M.Map RemoteConfigKey String
diff --git a/Utility/Metered.hs b/Utility/Metered.hs
new file mode 100644
index 000000000..f33ad443a
--- /dev/null
+++ b/Utility/Metered.hs
@@ -0,0 +1,116 @@
+{- Metered IO
+ -
+ - Copyright 2012, 2013 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+{-# LANGUAGE TypeSynonymInstances #-}
+
+module Utility.Metered where
+
+import Common
+
+import qualified Data.ByteString.Lazy as L
+import qualified Data.ByteString as S
+import System.IO.Unsafe
+import Foreign.Storable (Storable(sizeOf))
+import System.Posix.Types
+
+{- An action that can be run repeatedly, updating it on the bytes processed.
+ -
+ - Note that each call receives the total number of bytes processed, so
+ - far, *not* an incremental amount since the last call. -}
+type MeterUpdate = (BytesProcessed -> IO ())
+
+{- Total number of bytes processed so far. -}
+newtype BytesProcessed = BytesProcessed Integer
+	deriving (Eq, Ord)
+
+class AsBytesProcessed a where
+	toBytesProcessed :: a -> BytesProcessed
+	fromBytesProcessed :: BytesProcessed -> a
+
+instance AsBytesProcessed Integer where
+	toBytesProcessed i = BytesProcessed i
+	fromBytesProcessed (BytesProcessed i) = i
+
+instance AsBytesProcessed Int where
+	toBytesProcessed i = BytesProcessed $ toInteger i
+	fromBytesProcessed (BytesProcessed i) = fromInteger i
+
+instance AsBytesProcessed FileOffset where
+	toBytesProcessed sz = BytesProcessed $ toInteger sz
+	fromBytesProcessed (BytesProcessed sz) = fromInteger sz
+
+addBytesProcessed :: AsBytesProcessed v => BytesProcessed -> v -> BytesProcessed
+addBytesProcessed (BytesProcessed i) v = 
+	let (BytesProcessed n) = toBytesProcessed v
+	in BytesProcessed $! i + n
+
+zeroBytesProcessed :: BytesProcessed
+zeroBytesProcessed = BytesProcessed 0
+
+{- Sends the content of a file to an action, updating the meter as it's
+ - consumed. -}
+withMeteredFile :: FilePath -> MeterUpdate -> (L.ByteString -> IO a) -> IO a
+withMeteredFile f meterupdate a = withBinaryFile f ReadMode $ \h ->
+	hGetContentsMetered h meterupdate >>= a
+
+{- Sends the content of a file to a Handle, updating the meter as it's
+ - written. -}
+streamMeteredFile :: FilePath -> MeterUpdate -> Handle -> IO ()
+streamMeteredFile f meterupdate h = withMeteredFile f meterupdate $ L.hPut h
+
+{- Writes a ByteString to a Handle, updating a meter as it's written. -}
+meteredWrite :: MeterUpdate -> Handle -> L.ByteString -> IO ()
+meteredWrite meterupdate h = go zeroBytesProcessed . L.toChunks 
+  where
+	go _ [] = return ()
+	go sofar (c:cs) = do
+		S.hPut h c
+		let sofar' = addBytesProcessed sofar $ S.length c
+		meterupdate sofar'
+		go sofar' cs
+
+meteredWriteFile :: MeterUpdate -> FilePath -> L.ByteString -> IO ()
+meteredWriteFile meterupdate f b = withBinaryFile f WriteMode $ \h ->
+	meteredWrite meterupdate h b
+
+{- This is like L.hGetContents, but after each chunk is read, a meter
+ - is updated based on the size of the chunk.
+ -
+ - Note that the meter update is run in unsafeInterleaveIO, which means that
+ - it can be run at any time. It's even possible for updates to run out
+ - of order, as different parts of the ByteString are consumed.
+ -
+ - All the usual caveats about using unsafeInterleaveIO apply to the
+ - meter updates, so use caution.
+ -}
+hGetContentsMetered :: Handle -> MeterUpdate -> IO L.ByteString
+hGetContentsMetered h meterupdate = lazyRead zeroBytesProcessed
+  where
+	lazyRead sofar = unsafeInterleaveIO $ loop sofar
+
+	loop sofar = do
+		c <- S.hGetSome h defaultChunkSize
+		if S.null c
+			then do
+				hClose h
+				return $ L.empty
+			else do
+				let sofar' = addBytesProcessed sofar $
+					S.length c
+				meterupdate sofar'
+				{- unsafeInterleaveIO causes this to be
+				 - deferred until the data is read from the
+				 - ByteString. -}
+				cs <- lazyRead sofar'
+				return $ L.append (L.fromChunks [c]) cs
+
+{- Same default chunk size Lazy ByteStrings use. -}
+defaultChunkSize :: Int
+defaultChunkSize = 32 * k - chunkOverhead
+  where
+	k = 1024
+	chunkOverhead = 2 * sizeOf (undefined :: Int) -- GHC specific
diff --git a/Utility/Observed.hs b/Utility/Observed.hs
deleted file mode 100644
index 3ee973429..000000000
--- a/Utility/Observed.hs
+++ /dev/null
@@ -1,43 +0,0 @@
-module Utility.Observed where
-
-import qualified Data.ByteString.Lazy as L
-import qualified Data.ByteString as S
-import System.IO
-import System.IO.Unsafe
-import Foreign.Storable (Storable(sizeOf))
-
-{- This is like L.hGetContents, but after each chunk is read, an action
- - is run to observe the size of the chunk.
- -
- - Note that the observer is run in unsafeInterleaveIO, which means that
- - it can be run at any time. It's even possible for observers to run out
- - of order, as different parts of the ByteString are consumed.
- -
- - All the usual caveats about using unsafeInterleaveIO apply to the observers,
- - so use caution.
- -}
-hGetContentsObserved :: Handle -> (Int -> IO ()) -> IO L.ByteString
-hGetContentsObserved h observe = lazyRead
-  where
-	lazyRead = unsafeInterleaveIO loop
-
-	loop = do
-		c <- S.hGetSome h defaultChunkSize
-		if S.null c
-			then do
-				hClose h
-				return $ L.empty
-			else do
-				observe $ S.length c
-				{- unsafeInterleaveIO causes this to be
-				 - deferred until the data is read from the
-				 - ByteString. -}
-				cs <- lazyRead
-				return $ L.append (L.fromChunks [c]) cs
-
-{- Same default chunk size Lazy ByteStrings use. -}
-defaultChunkSize :: Int
-defaultChunkSize = 32 * k - chunkOverhead
-  where
-	k = 1024
-	chunkOverhead = 2 * sizeOf (undefined :: Int) -- GHC specific
diff --git a/Utility/Rsync.hs b/Utility/Rsync.hs
index e03824239..afb3dcbc8 100644
--- a/Utility/Rsync.hs
+++ b/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).
diff --git a/debian/changelog b/debian/changelog
index 38c329dcd..96cca734d 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -4,6 +4,7 @@ git-annex (4.20130324) UNRELEASED; urgency=low
   * Per-command usage messages.
   * webapp: Fix a race that sometimes caused alerts or other notifications
     to be missed if they occurred while a page was loading.
+  * webapp: Progess bar fixes for many types of special remotes.
 
  -- Joey Hess <joeyh@debian.org>  Mon, 25 Mar 2013 10:21:46 -0400
 
diff --git a/doc/bugs/No_progress_bars_with_S3.mdwn b/doc/bugs/No_progress_bars_with_S3.mdwn
index 907b3cb11..afa7ba5ee 100644
--- a/doc/bugs/No_progress_bars_with_S3.mdwn
+++ b/doc/bugs/No_progress_bars_with_S3.mdwn
@@ -19,3 +19,8 @@ I expect a changing status bar and percentage. Instead I see no changes when an
 When uploading local data to an S3 remote, I see no progress bars. The progress bar area on active uploads stays the same grey as the bar on queued uploads. The status does not change from "0% of...". The uploads are completing, but this makes it very difficult to judge their activity.
 
 The only remotes I currently have setup are S3 special remotes, so I cannot say whether progress bars are working for uploads to other remote types.
+
+> [[done]], this turned out to be a confusion in the progress code;
+> parts were expecting a full number of bytes since the start, while
+> other parts were sending the number of bytes in a chunk. Result was
+> progress bars stuck at 0% often. --[[Joey]]