speed up populating the importfeed database

Avoid conversion from ByteString to String for urls that will just be
converted right back to ByteString to go into the database.

Also setTempUrl is not used by importfeed, so avoid checking for temp
urls in this code path.

This benchmarks as only a small improvement. From 2.99s to 2.78s
when populating a database with 33k urls.

Note that it does not seem worth replacing URLString with URLByteString
generally, because the ways urls are used all entails either parseURI,
which takes a string, or passing a parameter to eg curl, which also is
currently a string.

Sponsored-by: Leon Schuermann on Patreon

Database/ImportFeed.hs

@@ -112,9 +112,9 @@ isKnownItemId (ImportFeedDbHandle h) i =
 			] []
 		return $ not (null l)
 
-recordKnownUrl :: ImportFeedDbHandle -> URLString -> IO ()
+recordKnownUrl :: ImportFeedDbHandle -> URLByteString -> IO ()
 recordKnownUrl h u = queueDb h $
-	void $ insertUniqueFast $ KnownUrls $ SByteString $ encodeBS u
+	void $ insertUniqueFast $ KnownUrls $ SByteString u
 
 recordKnownItemId :: ImportFeedDbHandle -> SByteString -> IO ()
 recordKnownItemId h i = queueDb h $
@@ -177,7 +177,7 @@ updateFromLog db@(ImportFeedDbHandle h) (oldtree, currtree)
 		let f = getTopFilePath (DiffTree.file ti)
 		case extLogFileKey urlLogExt f of
 			Just k -> do
-				knownurls =<< getUrls k
+				knownurls =<< getUrls' k
 			Nothing -> case extLogFileKey metaDataLogExt f of
 				Just k -> do
 					m <- getCurrentMetaData k

Logs/Web.hs

@@ -1,6 +1,6 @@
 {- Web url logs.
  -
- - Copyright 2011-2021 Joey Hess <id@joeyh.name>
+ - Copyright 2011-2023 Joey Hess <id@joeyh.name>
  -
  - Licensed under the GNU AGPL version 3 or higher.
  -}
@@ -9,7 +9,9 @@
 
 module Logs.Web (
 	URLString,
+	URLByteString,
 	getUrls,
+	getUrls',
 	getUrlsWithPrefix,
 	setUrlPresent,
 	setUrlMissing,
@@ -23,6 +25,7 @@ module Logs.Web (
 ) where
 
 import qualified Data.Map as M
+import qualified Data.ByteString as S
 import qualified Data.ByteString.Lazy as L
 
 import Annex.Common
@@ -35,20 +38,27 @@ import Annex.UUID
 import qualified Annex.Branch
 import qualified Types.Remote as Remote
 
+type URLByteString = S.ByteString
+
 {- Gets all urls that a key might be available from. -}
 getUrls :: Key -> Annex [URLString]
 getUrls key = do
-	config <- Annex.getGitConfig
+	l <- map decodeBS <$> getUrls' key
-	l <- go $ urlLogFile config key : oldurlLogs config key
 	tmpl <- Annex.getState (maybeToList . M.lookup key . Annex.tempurls)
 	return (tmpl ++ l)
+
+{- Note that this does not include temporary urls set with setTempUrl. -}
+getUrls' :: Key -> Annex [URLByteString]
+getUrls' key = do
+	config <- Annex.getGitConfig
+	go $ urlLogFile config key : oldurlLogs config key
   where
 	go [] = return []
 	go (l:ls) = do
 		us <- currentLogInfo l
 		if null us
 			then go ls
-			else return $ map decodeUrlLogInfo us
+			else return $ map fromLogInfo us
 
 getUrlsWithPrefix :: Key -> String -> Annex [URLString]
 getUrlsWithPrefix key prefix = filter (prefix `isPrefixOf`) 
@@ -123,10 +133,7 @@ getDownloader u = case separate (== ':') u of
 	("", u') -> (u', OtherDownloader)
 	_ -> (u, WebDownloader)
 
-decodeUrlLogInfo :: LogInfo -> URLString
-decodeUrlLogInfo = decodeBS . fromLogInfo
-
 {- Parses the content of an url log file, returning the urls that are
  - currently recorded. -}
-parseUrlLog :: L.ByteString -> [URLString]
+parseUrlLog :: L.ByteString -> [URLByteString]
-parseUrlLog = map decodeUrlLogInfo . getLog
+parseUrlLog = map fromLogInfo . getLog