incremental checksum on download from ssh or p2p

Checksum as content is received from a remote git-annex repository, rather
than doing it in a second pass.

Not tested at all yet, but I imagine it will work!

Not implemented for any special remotes, and also not implemented for
copies from local remotes. It may be that, for local remotes, it will
suffice to use rsync, rely on its checksumming, and simply return Verified.
(It would still make a checksumming pass when cp is used for COW, I guess.)

Annex/Content/Presence.hs

@@ -26,10 +26,10 @@ module Annex.Content.Presence (
 
 import Annex.Common
 import qualified Annex
+import Annex.Verify
 import Annex.LockPool
 import Annex.WorkerPool
 import Types.Remote (unVerified, Verification(..), RetrievalSecurityPolicy(..))
-import qualified Types.Remote
 import qualified Types.Backend
 import qualified Backend
 import qualified Database.Keys
@@ -231,16 +231,3 @@ warnUnverifiableInsecure k = warning $ unwords
 	]
   where
 	kv = decodeBS (formatKeyVariety (fromKey keyVariety k))
-
-data VerifyConfig = AlwaysVerify | NoVerify | RemoteVerify Remote | DefaultVerify
-
-shouldVerify :: VerifyConfig -> Annex Bool
-shouldVerify AlwaysVerify = return True
-shouldVerify NoVerify = return False
-shouldVerify DefaultVerify = annexVerify <$> Annex.getGitConfig
-shouldVerify (RemoteVerify r) = 
-	(shouldVerify DefaultVerify
-			<&&> pure (remoteAnnexVerify (Types.Remote.gitconfig r)))
-	-- Export remotes are not key/value stores, so always verify
-	-- content from them even when verification is disabled.
-	<||> Types.Remote.isExportSupported r

Annex/Verify.hs

@@ -0,0 +1,25 @@
+{- verification
+ -
+ - Copyright 2010-2021 Joey Hess <id@joeyh.name>
+ -
+ - Licensed under the GNU AGPL version 3 or higher.
+ -}
+
+module Annex.Verify where
+
+import Annex.Common
+import qualified Annex
+import qualified Types.Remote
+
+data VerifyConfig = AlwaysVerify | NoVerify | RemoteVerify Remote | DefaultVerify
+
+shouldVerify :: VerifyConfig -> Annex Bool
+shouldVerify AlwaysVerify = return True
+shouldVerify NoVerify = return False
+shouldVerify DefaultVerify = annexVerify <$> Annex.getGitConfig
+shouldVerify (RemoteVerify r) = 
+	(shouldVerify DefaultVerify
+			<&&> pure (remoteAnnexVerify (Types.Remote.gitconfig r)))
+	-- Export remotes are not key/value stores, so always verify
+	-- content from them even when verification is disabled.
+	<||> Types.Remote.isExportSupported r

Backend.hs

@@ -1,6 +1,6 @@
 {- git-annex key/value backends
  -
- - Copyright 2010-2020 Joey Hess <id@joeyh.name>
+ - Copyright 2010-2021 Joey Hess <id@joeyh.name>
  -
  - Licensed under the GNU AGPL version 3 or higher.
  -}
@@ -17,11 +17,13 @@ module Backend (
 	isStableKey,
 	isCryptographicallySecure,
 	isVerifiable,
+	startVerifyKeyContentIncrementally,
 ) where
 
 import Annex.Common
 import qualified Annex
 import Annex.CheckAttr
+import Annex.Verify
 import Types.Key
 import Types.KeySource
 import qualified Types.Backend as B
@@ -127,3 +129,14 @@ isCryptographicallySecure k = maybe False (`B.isCryptographicallySecure` k)
 isVerifiable :: Key -> Annex Bool
 isVerifiable k = maybe False (isJust . B.verifyKeyContent) 
 	<$> maybeLookupBackendVariety (fromKey keyVariety k)
+
+startVerifyKeyContentIncrementally :: VerifyConfig -> Key -> Annex (Maybe B.IncrementalVerifier)
+startVerifyKeyContentIncrementally verifyconfig k = 
+	ifM (shouldVerify verifyconfig)
+		( maybeLookupBackendVariety (fromKey keyVariety k) >>= \case
+			Just b -> case B.verifyKeyContentIncrementally b of
+				Just v -> Just <$> v k
+				Nothing -> return Nothing
+			Nothing -> return Nothing
+		, return Nothing
+		)

Backend/Hash.hs

@@ -145,8 +145,7 @@ sameCheckSum key s
 	expected = decodeBS (keyHash key)
 
 checkKeyChecksumIncremental :: Hash -> Key -> Annex IncrementalVerifier
-checkKeyChecksumIncremental hash key = liftIO $
-	(\h -> snd h key) (hasher hash)
+checkKeyChecksumIncremental hash key = liftIO $ (snd $ hasher hash) key
 
 keyHash :: Key -> S.ByteString
 keyHash = fst . splitKeyNameExtension

CHANGELOG

@@ -24,6 +24,8 @@ git-annex (8.20210128) UNRELEASED; urgency=medium
   * Include libkqueue.h file needed to build the assistant on BSDs.
   * Tahoe: Avoid verifying hash after download, since tahoe does sufficient
     verification itself.
+  * Checksum as content is received from a remote git-annex repository,
+    rather than doing it in a second pass.
 
  -- Joey Hess <id@joeyh.name>  Thu, 28 Jan 2021 12:34:32 -0400
 

P2P/Annex.hs

@@ -1,6 +1,6 @@
 {- P2P protocol, Annex implementation
  -
- - Copyright 2016-2018 Joey Hess <id@joeyh.name>
+ - Copyright 2016-2021 Joey Hess <id@joeyh.name>
  -
  - Licensed under the GNU AGPL version 3 or higher.
  -}
@@ -23,9 +23,11 @@ import P2P.IO
 import Logs.Location
 import Types.NumCopies
 import Utility.Metered
+import Types.Backend (IncrementalVerifier(..))
 
 import Control.Monad.Free
 import Control.Concurrent.STM
+import qualified Data.ByteString as S
 
 -- Full interpreter for Proto, that can receive and send objects.
 runFullProto :: RunState -> P2PConnection -> Proto a -> Annex (Either ProtoFailure a)
@@ -77,7 +79,7 @@ runLocal runst runner a = case a of
 			let runtransfer ti = 
 				Right <$> transfer download' k af Nothing (\p ->
 					logStatusAfter k $ getViaTmp rsp DefaultVerify k af $ \tmp ->
-						storefile (fromRawFilePath tmp) o l getb validitycheck p ti)
+						storefile (fromRawFilePath tmp) o l getb Nothing validitycheck p ti)
 			let fallback = return $ Left $
 				ProtoFailureMessage "transfer already in progress, or unable to take transfer lock"
 			checktransfer runtransfer fallback
@@ -85,10 +87,10 @@ runLocal runst runner a = case a of
 			Left e -> return $ Left $ ProtoFailureException e
 			Right (Left e) -> return $ Left e
 			Right (Right ok) -> runner (next ok)
-	StoreContentTo dest o l getb validitycheck next -> do
+	StoreContentTo dest incrementalverifier o l getb validitycheck next -> do
 		v <- tryNonAsync $ do
 			let runtransfer ti = Right
-				<$> storefile dest o l getb validitycheck nullMeterUpdate ti
+				<$> storefile dest o l getb incrementalverifier validitycheck nullMeterUpdate ti
 			let fallback = return $ Left $
 				ProtoFailureMessage "transfer failed"
 			checktransfer runtransfer fallback
@@ -154,15 +156,40 @@ runLocal runst runner a = case a of
 		-- a client.
 		Client _ -> ta nullMeterUpdate
 	
-	storefile dest (Offset o) (Len l) getb validitycheck p ti = do
-		let p' = offsetMeterUpdate p (toBytesProcessed o)
+	resumefromoffset o incrementalverifier p h
+		| o /= 0 = do
+			p' <- case incrementalverifier of
+				Just iv -> do
+					go iv o
+					return p
+				_ -> return $ offsetMeterUpdate p (toBytesProcessed o)
+			-- Make sure the handle is seeked to the offset.
+			-- (Reading the file probably left it there
+			-- when that was done, but let's be sure.)
+			hSeek h AbsoluteSeek o
+			return p'
+		| otherwise = return p
+	  where
+		go iv n
+			| n == 0 = return ()
+			| n > fromIntegral defaultChunkSize = do
+				updateIncremental iv =<< S.hGet h defaultChunkSize
+				go iv (n - fromIntegral defaultChunkSize)
+			| otherwise = 
+				updateIncremental iv =<< S.hGet h (fromIntegral n)
+
+	storefile dest (Offset o) (Len l) getb incrementalverifier validitycheck p ti = do
 		v <- runner getb
 		case v of
 			Right b -> do
 				liftIO $ withBinaryFile dest ReadWriteMode $ \h -> do
-					when (o /= 0) $
-						hSeek h AbsoluteSeek o
-					meteredWrite p' h b
+					p' <- resumefromoffset o incrementalverifier p h
+					let writechunk = case incrementalverifier of
+						Nothing -> \c -> S.hPut h c
+						Just iv -> \c -> do
+							S.hPut h c
+							updateIncremental iv c
+					meteredWrite p' writechunk b
 				indicatetransferred ti
 
 				rightsize <- do
@@ -170,8 +197,12 @@ runLocal runst runner a = case a of
 					return (toInteger sz == l + o)
 					
 				runner validitycheck >>= \case
-					Right (Just Valid) ->
-						return (rightsize, UnVerified)
+					Right (Just Valid) -> case incrementalverifier of
+						Just iv -> ifM (liftIO (finalizeIncremental iv) <&&> pure rightsize)
+							( return (True, Verified)
+							, return (False, UnVerified)
+							)
+						Nothing -> return (rightsize, UnVerified)
 					Right (Just Invalid) | l == 0 ->
 						-- Special case, for when
 						-- content was not

P2P/IO.hs

@@ -259,7 +259,7 @@ debugMessage conn prefix m = do
 -- connection. False is returned to indicate this problem.
 sendExactly :: Len -> L.ByteString -> Handle -> MeterUpdate -> IO Bool
 sendExactly (Len n) b h p = do
-	sent <- meteredWrite' p h (L.take (fromIntegral n) b)
+	sent <- meteredWrite' p (B.hPut h) (L.take (fromIntegral n) b)
 	return (fromBytesProcessed sent == n)
 
 receiveExactly :: Len -> Handle -> MeterUpdate -> IO L.ByteString

P2P/Protocol.hs

@@ -2,7 +2,7 @@
  -
  - See doc/design/p2p_protocol.mdwn
  -
- - Copyright 2016-2020 Joey Hess <id@joeyh.name>
+ - Copyright 2016-2021 Joey Hess <id@joeyh.name>
  -
  - Licensed under the GNU AGPL version 3 or higher.
  -}
@@ -18,6 +18,7 @@ import Types (Annex)
 import Types.Key
 import Types.UUID
 import Types.Remote (Verification(..), unVerified)
+import Types.Backend (IncrementalVerifier(..))
 import Utility.AuthToken
 import Utility.Applicative
 import Utility.PartialPrelude
@@ -266,7 +267,7 @@ data LocalF c
 	-- Note: The ByteString may not contain the entire remaining content
 	-- of the key. Only once the temp file size == Len has the whole
 	-- content been transferred.
-	| StoreContentTo FilePath Offset Len (Proto L.ByteString) (Proto (Maybe Validity)) ((Bool, Verification) -> c)
+	| StoreContentTo FilePath (Maybe IncrementalVerifier) Offset Len (Proto L.ByteString) (Proto (Maybe Validity)) ((Bool, Verification) -> c)
 	-- ^ Like StoreContent, but stores the content to a temp file.
 	| SetPresent Key UUID c
 	| CheckContentPresent Key (Bool -> c)
@@ -351,13 +352,13 @@ remove key = do
 	net $ sendMessage (REMOVE key)
 	checkSuccess
 
-get :: FilePath -> Key -> AssociatedFile -> Meter -> MeterUpdate -> Proto (Bool, Verification)
-get dest key af m p = 
+get :: FilePath -> Key -> Maybe IncrementalVerifier -> AssociatedFile -> Meter -> MeterUpdate -> Proto (Bool, Verification)
+get dest key iv af m p = 
 	receiveContent (Just m) p sizer storer $ \offset ->
 		GET offset (ProtoAssociatedFile af) key
   where
 	sizer = fileSize dest
-	storer = storeContentTo dest
+	storer = storeContentTo dest iv
 
 put :: Key -> AssociatedFile -> MeterUpdate -> Proto Bool
 put key af p = do

Remote/Bup.hs

@@ -167,7 +167,7 @@ store r buprepo = byteStorer $ \k b p -> do
 				}
 			else cmd
 		    feeder = \h -> do
-			meteredWrite p h b
+			meteredWrite p (S.hPut h) b
 			hClose h
 		in withCreateProcess cmd' (go feeder cmd')
   where

Remote/Git.hs

@@ -557,6 +557,7 @@ copyFromRemote'' repo forcersync r st@(State connpool _ _ _ _) key file dest met
 				then return v
 				else giveup "failed to retrieve content from remote"
 		else P2PHelper.retrieve
+			(Annex.Content.RemoteVerify r)
 			(\p -> Ssh.runProto r connpool (return (False, UnVerified)) (fallback p))
 			key file dest meterupdate
 	| otherwise = giveup "copying from non-ssh, non-http remote not supported"

Remote/Glacier.hs

@@ -9,6 +9,7 @@ module Remote.Glacier (remote, jobList, checkSaneGlacierCommand) where
 
 import qualified Data.Map as M
 import qualified Data.Text as T
+import qualified Data.ByteString as S
 import qualified Data.ByteString.Lazy as L
 
 import Annex.Common
@@ -168,7 +169,7 @@ store' r k b p = go =<< glacierEnv c gc u
 			{ std_in = CreatePipe }
 		in liftIO $ withCreateProcess cmd (go' cmd)
 	go' cmd (Just hin) _ _ pid = do
-		meteredWrite p hin b
+		meteredWrite p (S.hPut hin) b
 		hClose hin
 		forceSuccessProcess cmd pid
 	go' _ _ _ _ _ = error "internal"

Remote/Helper/Chunked/Legacy.hs

@@ -11,6 +11,7 @@ import Annex.Common
 import Remote.Helper.Chunked
 import Utility.Metered
 
+import qualified Data.ByteString as S
 import qualified Data.ByteString.Lazy as L
 
 {- This is an extension that's added to the usual file (or whatever)
@@ -117,4 +118,4 @@ meteredWriteFileChunks :: MeterUpdate -> FilePath -> [v] -> (v -> IO L.ByteStrin
 meteredWriteFileChunks meterupdate dest chunks feeder =
 	withBinaryFile dest WriteMode $ \h ->
 		forM_ chunks $
-			meteredWrite meterupdate h <=< feeder
+			meteredWrite meterupdate (S.hPut h) <=< feeder

Remote/Helper/P2P.hs

@@ -1,6 +1,6 @@
 {- Helpers for remotes using the git-annex P2P protocol.
  -
- - Copyright 2016-2020 Joey Hess <id@joeyh.name>
+ - Copyright 2016-2021 Joey Hess <id@joeyh.name>
  -
  - Licensed under the GNU AGPL version 3 or higher.
  -}
@@ -17,6 +17,7 @@ import Annex.Content
 import Messages.Progress
 import Utility.Metered
 import Types.NumCopies
+import Backend
 
 import Control.Concurrent
 
@@ -39,10 +40,11 @@ store runner k af p = do
 			Just False -> giveup "transfer failed"
 			Nothing -> remoteUnavail
 
-retrieve :: (MeterUpdate -> ProtoRunner (Bool, Verification)) -> Key -> AssociatedFile -> FilePath -> MeterUpdate -> Annex Verification
-retrieve runner k af dest p =
+retrieve :: VerifyConfig -> (MeterUpdate -> ProtoRunner (Bool, Verification)) -> Key -> AssociatedFile -> FilePath -> MeterUpdate -> Annex Verification
+retrieve verifyconfig runner k af dest p = do
+	iv <- startVerifyKeyContentIncrementally verifyconfig k
 	metered (Just p) k $ \m p' -> 
-		runner p' (P2P.get dest k af m p') >>= \case
+		runner p' (P2P.get dest k iv af m p') >>= \case
 			Just (True, v) -> return v
 			Just (False, _) -> giveup "transfer failed"
 			Nothing -> remoteUnavail

Remote/Helper/Special.hs

@@ -295,7 +295,7 @@ sink dest enc c mh mp content = case (enc, mh, content) of
 		Just h -> liftIO $ b `streamto` h
 		Nothing -> liftIO $ bracket opendest hClose (b `streamto`)
 	streamto b h = case mp of
-		Just p -> meteredWrite p h b
+		Just p -> meteredWrite p (S.hPut h) b
 		Nothing -> L.hPut h b
 	opendest = openBinaryFile dest WriteMode
 

Remote/P2P.hs

@@ -13,6 +13,7 @@ module Remote.P2P (
 import Annex.Common
 import qualified Annex
 import qualified P2P.Protocol as P2P
+import qualified Annex.Content
 import P2P.Address
 import P2P.Annex
 import P2P.IO
@@ -56,7 +57,7 @@ chainGen addr r u rc gc rs = do
 		, cost = cst
 		, name = Git.repoDescribe r
 		, storeKey = store (const protorunner)
-		, retrieveKeyFile = retrieve (const protorunner)
+		, retrieveKeyFile = retrieve (Annex.Content.RemoteVerify this) (const protorunner)
 		, retrieveKeyFileCheap = Nothing
 		, retrievalSecurityPolicy = RetrievalAllKeysSecure
 		, removeKey = remove protorunner

Utility/Metered.hs

@@ -1,6 +1,6 @@
 {- Metered IO and actions
  -
- - Copyright 2012-2020 Joey Hess <id@joeyh.name>
+ - Copyright 2012-2021 Joey Hess <id@joeyh.name>
  -
  - License: BSD-2-clause
  -}
@@ -118,23 +118,24 @@ withMeteredFile :: FilePath -> MeterUpdate -> (L.ByteString -> IO a) -> IO a
 withMeteredFile f meterupdate a = withBinaryFile f ReadMode $ \h ->
 	hGetContentsMetered h meterupdate >>= a
 
-{- Writes a ByteString to a Handle, updating a meter as it's written. -}
-meteredWrite :: MeterUpdate -> Handle -> L.ByteString -> IO ()
-meteredWrite meterupdate h = void . meteredWrite' meterupdate h
+{- Calls the action repeatedly with chunks from the lazy ByteString.
+ - Updates the meter after each chunk is processed. -}
+meteredWrite :: MeterUpdate -> (S.ByteString -> IO ()) -> L.ByteString -> IO ()
+meteredWrite meterupdate a = void . meteredWrite' meterupdate a
 
-meteredWrite' :: MeterUpdate -> Handle -> L.ByteString -> IO BytesProcessed
-meteredWrite' meterupdate h = go zeroBytesProcessed . L.toChunks 
+meteredWrite' :: MeterUpdate -> (S.ByteString -> IO ()) -> L.ByteString -> IO BytesProcessed
+meteredWrite' meterupdate a = go zeroBytesProcessed . L.toChunks 
   where
 	go sofar [] = return sofar
 	go sofar (c:cs) = do
-		S.hPut h c
+		a 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
+	meteredWrite meterupdate (S.hPut h) b
 
 {- Applies an offset to a MeterUpdate. This can be useful when
  - performing a sequence of actions, such as multiple meteredWriteFiles,

git-annex.cabal

@@ -671,9 +671,10 @@ Executable git-annex
     Annex.UpdateInstead
     Annex.UUID
     Annex.Url
+    Annex.VariantFile
     Annex.VectorClock
     Annex.VectorClock.Utility
-    Annex.VariantFile
+    Annex.Verify
     Annex.Version
     Annex.View
     Annex.View.ViewedFile