add web special remote

Generalized LocationLog to PresenceLog, and use a presence log to record
urls for the web special remote.

Backend/File.hs

@@ -135,8 +135,8 @@ showLocations key exclude = do
 	untrusteduuids <- trustGet UnTrusted
 	let uuidswanted = filteruuids uuids (u:exclude++untrusteduuids) 
 	let uuidsskipped = filteruuids uuids (u:exclude++uuidswanted)
-	ppuuidswanted <- prettyPrintUUIDs uuidswanted
-	ppuuidsskipped <- prettyPrintUUIDs uuidsskipped
+	ppuuidswanted <- Remote.prettyPrintUUIDs uuidswanted
+	ppuuidsskipped <- Remote.prettyPrintUUIDs uuidsskipped
 	showLongNote $ message ppuuidswanted ppuuidsskipped
 	where
 		filteruuids list x = filter (`notElem` x) list
@@ -195,7 +195,7 @@ checkKeyNumCopies key file numcopies = do
 	let present = length safelocations
 	if present < needed
 		then do
-			ppuuids <- prettyPrintUUIDs untrustedlocations
+			ppuuids <- Remote.prettyPrintUUIDs untrustedlocations
 			warning $ missingNote (filename file key) present needed ppuuids
 			return False
 		else return True

Command/Add.hs

@@ -51,7 +51,7 @@ perform (file, backend) = do
 
 cleanup :: FilePath -> Key -> CommandCleanup
 cleanup file key = do
-	logStatus key ValuePresent
+	logStatus key InfoPresent
 
 	link <- calcGitLink file key
 	liftIO $ createSymbolicLink link file

Command/Drop.hs

@@ -45,5 +45,5 @@ perform key backend numcopies = do
 cleanup :: Key -> CommandCleanup
 cleanup key = do
 	whenM (inAnnex key) $ removeAnnex key
-	logStatus key ValueMissing
+	logStatus key InfoMissing
 	return True

Command/DropKey.hs

@@ -40,5 +40,5 @@ perform key = do
 
 cleanup :: Key -> CommandCleanup
 cleanup key = do
-	logStatus key ValueMissing
+	logStatus key InfoMissing
 	return True

Command/Fsck.hs

@@ -64,11 +64,11 @@ verifyLocationLog key file = do
 
 	case (present, u `elem` uuids) of
 		(True, False) -> do
-				fix g u ValuePresent
+				fix g u InfoPresent
 				-- There is no data loss, so do not fail.
 				return True
 		(False, True) -> do
-				fix g u ValueMissing
+				fix g u InfoMissing
 				warning $
 					"** Based on the location log, " ++ file
 					++ "\n** was expected to be present, " ++

Command/Move.hs

@@ -58,7 +58,7 @@ remoteHasKey remote key present	= do
 	g <- Annex.gitRepo
 	logChange g key remoteuuid status
 	where
-		status = if present then ValuePresent else ValueMissing
+		status = if present then InfoPresent else InfoMissing
 
 {- Moves (or copies) the content of an annexed file to a remote.
  -

Command/SetKey.hs

@@ -46,5 +46,5 @@ perform file = do
 cleanup :: CommandCleanup
 cleanup = do
 	key <- cmdlineKey
-	logStatus key ValuePresent
+	logStatus key InfoPresent
 	return True

Command/Unannex.hs

@@ -65,7 +65,7 @@ cleanup file key = do
 	liftIO $ createDirectoryIfMissing True (parentDir file)
 
 	fromAnnex key file
-	logStatus key ValueMissing
+	logStatus key InfoMissing
 	
 	-- Commit staged changes at end to avoid confusing the
 	-- pre-commit hook if this file is later added back to

Command/Whereis.hs

@@ -10,7 +10,7 @@ module Command.Whereis where
 import LocationLog
 import Command
 import Messages
-import UUID
+import Remote
 import Types
 
 command :: [Command]

Content.hs

@@ -65,12 +65,7 @@ calcGitLink file key = do
 		whoops = error $ "unable to normalize " ++ file
 
 {- Updates the LocationLog when a key's presence changes in the current
- - repository.
- -
- - Note that the LocationLog is not updated in bare repositories.
- - Operations that change a bare repository should be done from
- - a non-bare repository, and the LocationLog in that repository be
- - updated instead. -}
+ - repository. -}
 logStatus :: Key -> LogStatus -> Annex ()
 logStatus key status = do
 	g <- Annex.gitRepo
@@ -112,7 +107,7 @@ getViaTmpUnchecked key action = do
 	if success
 		then do
 			moveAnnex key tmp
-			logStatus key ValuePresent
+			logStatus key InfoPresent
 			return True
 		else do
 			-- the tmp file is left behind, in case caller wants
@@ -240,7 +235,7 @@ moveBad key = do
 		allowWrite (parentDir src)
 		renameFile src dest
 		removeDirectory (parentDir src)
-	logStatus key ValueMissing
+	logStatus key InfoMissing
 	return dest
 
 {- List of keys whose content exists in .git/annex/objects/ -}

LocationLog.hs

@@ -5,11 +5,6 @@
  -
  - Repositories record their UUID and the date when they --get or --drop
  - a value.
- -
- - A line of the log will look like: "date N UUID"
- - Where N=1 when the repo has the file, and 0 otherwise.
- - (After the UUID can optionally come a white space and other data, 
- - for future expansion.)
  - 
  - Copyright 2010-2011 Joey Hess <joey@kitenet.net>
  -
@@ -25,61 +20,16 @@ module LocationLog (
 	loggedKeys
 ) where
 
-import Data.Time.Clock.POSIX
-import Data.Time
-import System.Locale
 import System.FilePath
-import qualified Data.Map as Map
 import Control.Monad (when)
 import Data.Maybe
-import Control.Monad.State (liftIO)
 
 import qualified Git
 import qualified Branch
 import UUID
 import Types
 import Locations
-
-data LogLine = LogLine {
-	date :: POSIXTime,
-	status :: LogStatus,
-	uuid :: UUID
-} deriving (Eq)
-
-data LogStatus = ValuePresent | ValueMissing | Undefined
-	deriving (Eq)
-
-instance Show LogStatus where
-	show ValuePresent = "1"
-	show ValueMissing = "0"
-	show Undefined = "undefined"
-
-instance Read LogStatus where
-	readsPrec _ "1" = [(ValuePresent, "")]
-	readsPrec _ "0" = [(ValueMissing, "")]
-	readsPrec _ _   = [(Undefined, "")]
-
-instance Show LogLine where
-	show (LogLine d s u) = unwords [show d, show s, u]
-
-instance Read LogLine where
-	-- This parser is robust in that even unparsable log lines are
-	-- read without an exception being thrown.
-	-- Such lines have a status of Undefined.
-	readsPrec _ string = 
-		if length w >= 3
-			then maybe bad good pdate
-			else bad
-		where
-			w = words string
-			s = read $ w !! 1
-			u = w !! 2
-			pdate :: Maybe UTCTime
-			pdate = parseTime defaultTimeLocale "%s%Qs" $ head w
-
-			good v = ret $ LogLine (utcTimeToPOSIXSeconds v) s u
-			bad = ret $ LogLine 0 Undefined ""
-			ret v = [(v, "")]
+import PresenceLog
 
 {- Log a change in the presence of a key's value in a repository. -}
 logChange :: Git.Repo -> Key -> UUID -> LogStatus -> Annex ()
@@ -92,59 +42,10 @@ logChange repo key u s = do
 	ls <- readLog f
 	writeLog f (compactLog $ line:ls)
 
-{- Reads a log file.
- - Note that the LogLines returned may be in any order. -}
-readLog :: FilePath -> Annex [LogLine]
-readLog file = return . parseLog =<< Branch.get file
-
-parseLog :: String -> [LogLine]
-parseLog s = filter parsable $ map read $ lines s
-	where
-		-- some lines may be unparseable, avoid them
-		parsable l = status l /= Undefined
-
-{- Stores a set of lines in a log file -}
-writeLog :: FilePath -> [LogLine] -> Annex ()
-writeLog file ls = Branch.change file (unlines $ map show ls)
-
-{- Generates a new LogLine with the current date. -}
-logNow :: LogStatus -> UUID -> Annex LogLine
-logNow s u = do
-	now <- liftIO $ getPOSIXTime
-	return $ LogLine now s u
-
 {- Returns a list of repository UUIDs that, according to the log, have
  - the value of a key. -}
 keyLocations :: Key -> Annex [UUID]
-keyLocations key = do
-	ls <- readLog $ logFile key
-	return $ map uuid $ filterPresent ls
-
-{- Filters the list of LogLines to find ones where the value
- - is (or should still be) present. -}
-filterPresent :: [LogLine] -> [LogLine]
-filterPresent ls = filter (\l -> ValuePresent == status l) $ compactLog ls
-
-type LogMap = Map.Map UUID LogLine
-
-{- Compacts a set of logs, returning a subset that contains the current
- - status. -}
-compactLog :: [LogLine] -> [LogLine]
-compactLog ls = compactLog' Map.empty ls
-compactLog' :: LogMap -> [LogLine] -> [LogLine]
-compactLog' m [] = Map.elems m
-compactLog' m (l:ls) = compactLog' (mapLog m l) ls
-
-{- Inserts a log into a map of logs, if the log has better (ie, newer)
- - information about a repo than the other logs in the map -}
-mapLog :: LogMap -> LogLine -> LogMap
-mapLog m l = 
-	if better
-		then Map.insert u l m
-		else m
-	where
-		better = maybe True (\l' -> date l' <= date l) $ Map.lookup u m
-		u = uuid l
+keyLocations key = currentLog $ logFile key
 
 {- Finds all keys that have location log information.
  - (There may be duplicate keys in the list.) -}

PresenceLog.hs

@@ -0,0 +1,123 @@
+{- git-annex presence log
+ -
+ - This is used to store presence information in the git-annex branch in
+ - a way that can be union merged.
+ -
+ - A line of the log will look like: "date N INFO"
+ - Where N=1 when the INFO is present, and 0 otherwise.
+ - 
+ - Copyright 2010-2011 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module PresenceLog (
+	LogStatus(..),
+	readLog,
+	writeLog,
+	logNow,
+	compactLog,
+	currentLog
+) where
+
+import Data.Time.Clock.POSIX
+import Data.Time
+import System.Locale
+import qualified Data.Map as Map
+import Control.Monad.State (liftIO)
+
+import qualified Branch
+import Types
+
+data LogLine = LogLine {
+	date :: POSIXTime,
+	status :: LogStatus,
+	info :: String
+} deriving (Eq)
+
+data LogStatus = InfoPresent | InfoMissing | Undefined
+	deriving (Eq)
+
+instance Show LogStatus where
+	show InfoPresent = "1"
+	show InfoMissing = "0"
+	show Undefined = "undefined"
+
+instance Read LogStatus where
+	readsPrec _ "1" = [(InfoPresent, "")]
+	readsPrec _ "0" = [(InfoMissing, "")]
+	readsPrec _ _   = [(Undefined, "")]
+
+instance Show LogLine where
+	show (LogLine d s i) = unwords [show d, show s, i]
+
+instance Read LogLine where
+	-- This parser is robust in that even unparsable log lines are
+	-- read without an exception being thrown.
+	-- Such lines have a status of Undefined.
+	readsPrec _ string = 
+		if length w >= 3
+			then maybe bad good pdate
+			else bad
+		where
+			w = words string
+			s = read $ w !! 1
+			i = w !! 2
+			pdate :: Maybe UTCTime
+			pdate = parseTime defaultTimeLocale "%s%Qs" $ head w
+
+			good v = ret $ LogLine (utcTimeToPOSIXSeconds v) s i
+			bad = ret $ LogLine 0 Undefined ""
+			ret v = [(v, "")]
+
+{- Reads a log file.
+ - Note that the LogLines returned may be in any order. -}
+readLog :: FilePath -> Annex [LogLine]
+readLog file = return . parseLog =<< Branch.get file
+
+parseLog :: String -> [LogLine]
+parseLog s = filter parsable $ map read $ lines s
+	where
+		-- some lines may be unparseable, avoid them
+		parsable l = status l /= Undefined
+
+{- Stores a set of lines in a log file -}
+writeLog :: FilePath -> [LogLine] -> Annex ()
+writeLog file ls = Branch.change file (unlines $ map show ls)
+
+{- Generates a new LogLine with the current date. -}
+logNow :: LogStatus -> String -> Annex LogLine
+logNow s i = do
+	now <- liftIO $ getPOSIXTime
+	return $ LogLine now s i
+
+{- Reads a log and returns only the info that is still in effect. -}
+currentLog :: FilePath -> Annex [String]
+currentLog file = do
+	ls <- readLog file
+	return $ map info $ filterPresent ls
+
+{- Returns the info from LogLines that are in effect. -}
+filterPresent :: [LogLine] -> [LogLine]
+filterPresent ls = filter (\l -> InfoPresent == status l) $ compactLog ls
+
+type LogMap = Map.Map String LogLine
+
+{- Compacts a set of logs, returning a subset that contains the current
+ - status. -}
+compactLog :: [LogLine] -> [LogLine]
+compactLog ls = compactLog' Map.empty ls
+compactLog' :: LogMap -> [LogLine] -> [LogLine]
+compactLog' m [] = Map.elems m
+compactLog' m (l:ls) = compactLog' (mapLog m l) ls
+
+{- Inserts a log into a map of logs, if the log has better (ie, newer)
+ - information than the other logs in the map -}
+mapLog :: LogMap -> LogLine -> LogMap
+mapLog m l = 
+	if better
+		then Map.insert i l m
+		else m
+	where
+		better = maybe True (\l' -> date l' <= date l) $ Map.lookup i m
+		i = info l

Remote.hs

@@ -24,6 +24,7 @@ module Remote (
 	nameToUUID,
 	remotesWithUUID,
 	remotesWithoutUUID,
+	prettyPrintUUIDs,
 
 	remoteLog,
 	readRemoteLog,
@@ -34,7 +35,7 @@ module Remote (
 	prop_idempotent_configEscape
 ) where
 
-import Control.Monad (filterM)
+import Control.Monad (filterM, liftM2)
 import Data.List
 import qualified Data.Map as M
 import Data.Maybe
@@ -54,6 +55,7 @@ import qualified Remote.S3
 import qualified Remote.Bup
 import qualified Remote.Directory
 import qualified Remote.Rsync
+import qualified Remote.Web
 import qualified Remote.Hook
 
 remoteTypes :: [RemoteType Annex]
@@ -63,6 +65,7 @@ remoteTypes =
 	, Remote.Bup.remote
 	, Remote.Directory.remote
 	, Remote.Rsync.remote
+	, Remote.Web.remote
 	, Remote.Hook.remote
 	]
 
@@ -120,6 +123,24 @@ nameToUUID n = do
 		invertMap = M.fromList . map swap . M.toList
 		swap (a, b) = (b, a)
 
+{- Pretty-prints a list of UUIDs of remotes. -}
+prettyPrintUUIDs :: [UUID] -> Annex String
+prettyPrintUUIDs uuids = do
+	here <- getUUID =<< Annex.gitRepo
+	-- Show descriptions from the uuid log, falling back to remote names,
+	-- as some remotes may not be in the uuid log.
+	m <- liftM2 M.union uuidMap $
+		return . M.fromList . map (\r -> (uuid r, name r)) =<< genList
+	return $ unwords $ map (\u -> "\t" ++ prettify m u here ++ "\n") uuids
+	where
+		prettify m u here = base ++ ishere
+			where
+				base = if not $ null $ findlog m u
+					then u ++ "  -- " ++ findlog m u
+					else u
+				ishere = if here == u then " <-- here" else ""
+		findlog m u = M.findWithDefault "" u m
+
 {- Filters a list of remotes to ones that have the listed uuids. -}
 remotesWithUUID :: [Remote Annex] -> [UUID] -> [Remote Annex]
 remotesWithUUID rs us = filter (\r -> uuid r `elem` us) rs

Remote/Web.hs

@@ -0,0 +1,107 @@
+{- Web remotes.
+ -
+ - Copyright 2011 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module Remote.Web (
+	remote
+) where
+
+import Control.Monad.State (liftIO)
+import Control.Exception
+import System.FilePath
+import Network.Curl.Easy
+import Network.Curl.Opts
+import Network.Curl.Types
+import Network.Curl.Code
+
+import Types
+import Types.Remote
+import qualified Git
+import Messages
+import Utility
+import UUID
+import Config
+import PresenceLog
+
+remote :: RemoteType Annex
+remote = RemoteType {
+	typename = "web",
+	enumerate = list,
+	generate = gen,
+	setup = error "not supported"
+}
+
+-- There is only one web remote, and it always exists.
+-- (If the web should cease to exist, remove this module and redistribute
+-- a new release to the survivors by carrier pigeon.)
+list :: Annex [Git.Repo]
+list = return [Git.repoRemoteNameSet Git.repoFromUnknown "remote.web.dummy"]
+
+-- Dummy uuid for the whole web. Do not alter.
+webUUID :: UUID
+webUUID = "00000000-0000-0000-0000-000000000001"
+
+gen :: Git.Repo -> UUID -> Maybe RemoteConfig -> Annex (Remote Annex)
+gen r _ _ = 
+	return $ Remote {
+		uuid = webUUID,
+		cost = expensiveRemoteCost,
+		name = Git.repoDescribe r,
+		storeKey = upload,
+		retrieveKeyFile = download,
+		removeKey = remove,
+		hasKey = check,
+		hasKeyCheap = False,
+		config = Nothing
+	}
+
+{- The urls for a key are stored in remote/web/key.log in the git-annex branch. -}
+urlLog :: Key -> FilePath
+urlLog key = "remote/web" </> show key ++ ".log"
+
+urls :: Key -> Annex [URLString]
+urls key = currentLog (urlLog key)
+
+download :: Key -> FilePath -> Annex Bool
+download key file = download' file =<< urls key
+download' :: FilePath -> [URLString] -> Annex Bool
+download' _ [] = return False
+download' file (url:us) = do
+	showProgress -- make way for curl progress bar
+	ok <- liftIO $ boolSystem "curl" [Params "-# -o", File file, File url]
+	if ok then return ok else download' file us
+
+upload :: Key -> Annex Bool
+upload _ = do
+	warning "upload to web not supported"
+	return False
+
+remove :: Key -> Annex Bool
+remove _ = do
+	warning "removal from web not supported"
+	return False
+
+check :: Key -> Annex (Either IOException Bool)
+check key = do
+	us <- urls key
+	if null us
+		then return $ Right False
+		else return . Right =<< check' us
+check' :: [URLString] -> Annex Bool
+check' [] = return False
+check' (u:us) = do
+	showNote ("checking " ++ u)
+	e <- liftIO $ urlexists u
+	if e then return e else check' us
+
+urlexists :: URLString -> IO Bool
+urlexists url = do
+	curl <- initialize
+	_ <- setopt curl (CurlURL url)
+	_ <- setopt curl (CurlNoBody True)
+	_ <- setopt curl (CurlFailOnError True)
+	res <- perform curl
+	return $ res == CurlOK

UUID.hs

@@ -17,7 +17,6 @@ module UUID (
 	getUncachedUUID,
 	prepUUID,
 	genUUID,
-	prettyPrintUUIDs,
 	describeUUID,
 	uuidMap,
 	uuidLog
@@ -86,21 +85,6 @@ prepUUID = do
 		uuid <- liftIO $ genUUID
 		setConfig configkey uuid
 
-{- Pretty-prints a list of UUIDs -}
-prettyPrintUUIDs :: [UUID] -> Annex String
-prettyPrintUUIDs uuids = do
-	here <- getUUID =<< Annex.gitRepo
-	m <- uuidMap
-	return $ unwords $ map (\u -> "\t" ++ prettify m u here ++ "\n") uuids
-	where
-		prettify m u here = base ++ ishere
-			where
-				base = if not $ null $ findlog m u
-					then u ++ "  -- " ++ findlog m u
-					else u
-				ishere = if here == u then " <-- here" else ""
-		findlog m u = M.findWithDefault "" u m
-
 {- Records a description for a uuid in the uuidLog. -}
 describeUUID :: UUID -> String -> Annex ()
 describeUUID uuid desc = do

debian/changelog

@@ -1,5 +1,7 @@
 git-annex (3.20110625) UNRELEASED; urgency=low
 
+  * Now the web can be used as a special remote. This feature
+    replaces the old URL backend.
   * Sped back up fsck, copy --from, and other commands that often
     have to read a lot of information from the git-annex branch. Such
     commands are now faster than they were before introduction of the