unify exception handling into Utility.Exception

Removed old extensible-exceptions, only needed for very old ghc.

Made webdav use Utility.Exception, to work after some changes in DAV's
exception handling.

Removed Annex.Exception. Mostly this was trivial, but note that
tryAnnex is replaced with tryNonAsync and catchAnnex replaced with
catchNonAsync. In theory that could be a behavior change, since the former
caught all exceptions, and the latter don't catch async exceptions.

However, in practice, nothing in the Annex monad uses async exceptions.
Grepping for throwTo and killThread only find stuff in the assistant,
which does not seem related.

Command.Add.undo is changed to accept a SomeException, and things
that use it for rollback now catch non-async exceptions, rather than
only IOExceptions.

9 files changed, 40 insertions, 29 deletions

diff --git a/Utility/Directory.hs b/Utility/Directory.hs
index ade5ef811..a4429d5b9 100644
--- a/Utility/Directory.hs
+++ b/Utility/Directory.hs
@@ -11,7 +11,6 @@ module Utility.Directory where
 
 import System.IO.Error
 import System.Directory
-import Control.Exception (throw, bracket)
 import Control.Monad
 import Control.Monad.IfElse
 import System.FilePath
@@ -114,7 +113,7 @@ moveFile src dest = tryIO (rename src dest) >>= onrename
 			whenM (isdir dest) rethrow
 			viaTmp mv dest undefined
 	  where
-		rethrow = throw e
+		rethrow = throwM e
 		mv tmp _ = do
 			ok <- boolSystem "mv" [Param "-f", Param src, Param tmp]
 			unless ok $ do
diff --git a/Utility/Exception.hs b/Utility/Exception.hs
index 13c9d508a..802e9e24b 100644
--- a/Utility/Exception.hs
+++ b/Utility/Exception.hs
@@ -7,11 +7,25 @@
 
 {-# LANGUAGE ScopedTypeVariables #-}
 
-module Utility.Exception where
+module Utility.Exception (
+	module X,
+	catchBoolIO,
+	catchMaybeIO,
+	catchDefaultIO,
+	catchMsgIO,
+	catchIO,
+	tryIO,
+	bracketIO,
+	catchNonAsync,
+	tryNonAsync,
+	tryWhenExists,
+) where
 
+import Control.Monad.Catch as X hiding (Handler)
+import qualified Control.Monad.Catch as M
 import Control.Exception (IOException, AsyncException)
-import Control.Monad.Catch
 import Control.Monad
+import Control.Monad.IO.Class (liftIO, MonadIO)
 import System.IO.Error (isDoesNotExistError)
 import Utility.Data
 
@@ -44,14 +58,20 @@ catchIO = catch
 tryIO :: MonadCatch m => m a -> m (Either IOException a)
 tryIO = try
 
+{- bracket with setup and cleanup actions lifted to IO.
+ -
+ - Note that unlike catchIO and tryIO, this catches all exceptions. -}
+bracketIO :: (MonadMask m, MonadIO m) => IO v -> (v -> IO b) -> (v -> m a) -> m a
+bracketIO setup cleanup = bracket (liftIO setup) (liftIO . cleanup)
+
 {- Catches all exceptions except for async exceptions.
  - This is often better to use than catching them all, so that
  - ThreadKilled and UserInterrupt get through.
  -}
 catchNonAsync :: MonadCatch m => m a -> (SomeException -> m a) -> m a
 catchNonAsync a onerr = a `catches`
-	[ Handler (\ (e :: AsyncException) -> throwM e)
-	, Handler (\ (e :: SomeException) -> onerr e)
+	[ M.Handler (\ (e :: AsyncException) -> throwM e)
+	, M.Handler (\ (e :: SomeException) -> onerr e)
 	]
 
 tryNonAsync :: MonadCatch m => m a -> m (Either SomeException a)
diff --git a/Utility/FileMode.hs b/Utility/FileMode.hs
index c2ef683a8..832250bde 100644
--- a/Utility/FileMode.hs
+++ b/Utility/FileMode.hs
@@ -11,7 +11,6 @@ module Utility.FileMode where
 
 import System.IO
 import Control.Monad
-import Control.Exception (bracket)
 import System.PosixCompat.Types
 import Utility.PosixFiles
 #ifndef mingw32_HOST_OS
diff --git a/Utility/Gpg.hs b/Utility/Gpg.hs
index 410259b11..dfca82778 100644
--- a/Utility/Gpg.hs
+++ b/Utility/Gpg.hs
@@ -13,7 +13,6 @@ import Control.Applicative
 import Control.Concurrent
 import Control.Monad.IO.Class
 import qualified Data.Map as M
-import Control.Monad.Catch (bracket, MonadMask)
 
 import Common
 import qualified Build.SysConfig as SysConfig
diff --git a/Utility/Matcher.hs b/Utility/Matcher.hs
index 1ee224ffc..76f8903f5 100644
--- a/Utility/Matcher.hs
+++ b/Utility/Matcher.hs
@@ -102,13 +102,13 @@ findClose l =
 	in (Group (reverse g), rest)
   where
   	go c [] = (c, []) -- not picky about extra Close
-	go c (t:ts) = handle t
+	go c (t:ts) = dispatch t
 	  where
-		handle Close = (c, ts)
-		handle Open = 
+		dispatch Close = (c, ts)
+		dispatch Open = 
 			let (c', ts') = go [] ts
 			in go (Group (reverse c') : c) ts'
-		handle _ = go (One t:c) ts
+		dispatch _ = go (One t:c) ts
 
 {- Checks if a Matcher matches, using a supplied function to check
  - the value of Operations. -}
diff --git a/Utility/Parallel.hs b/Utility/Parallel.hs
index 239c81e7b..7966811ab 100644
--- a/Utility/Parallel.hs
+++ b/Utility/Parallel.hs
@@ -10,7 +10,6 @@ module Utility.Parallel where
 import Common
 
 import Control.Concurrent
-import Control.Exception
 
 {- Runs an action in parallel with a set of values, in a set of threads.
  - In order for the actions to truely run in parallel, requires GHC's
diff --git a/Utility/Tmp.hs b/Utility/Tmp.hs
index 7da5cc284..edd82f5ac 100644
--- a/Utility/Tmp.hs
+++ b/Utility/Tmp.hs
@@ -14,7 +14,6 @@ import System.Directory
 import Control.Monad.IfElse
 import System.FilePath
 import Control.Monad.IO.Class
-import Control.Monad.Catch (bracket, MonadMask)
 
 import Utility.Exception
 import Utility.FileSystemEncoding
@@ -33,11 +32,11 @@ viaTmp a file content = bracket setup cleanup use
 	setup = do
 		createDirectoryIfMissing True dir
 		openTempFile dir template
-	cleanup (tmpfile, handle) = do
-		_ <- tryIO $ hClose handle
+	cleanup (tmpfile, h) = do
+		_ <- tryIO $ hClose h
 		tryIO $ removeFile tmpfile
-	use (tmpfile, handle) = do
-		hClose handle
+	use (tmpfile, h) = do
+		hClose h
 		a tmpfile content
 		rename tmpfile file
 
@@ -54,10 +53,10 @@ withTmpFileIn :: (MonadIO m, MonadMask m) => FilePath -> Template -> (FilePath -
 withTmpFileIn tmpdir template a = bracket create remove use
   where
 	create = liftIO $ openTempFile tmpdir template
-	remove (name, handle) = liftIO $ do
-		hClose handle
+	remove (name, h) = liftIO $ do
+		hClose h
 		catchBoolIO (removeFile name >> return True)
-	use (name, handle) = a name handle
+	use (name, h) = a name h
 
 {- Runs an action with a tmp directory located within the system's tmp
  - directory (or within "." if there is none), then removes the tmp
diff --git a/Utility/Url.hs b/Utility/Url.hs
index bf2d3859c..4137a5d8b 100644
--- a/Utility/Url.hs
+++ b/Utility/Url.hs
@@ -51,11 +51,11 @@ checkBoth url expected_size uo = do
 	v <- check url expected_size uo
 	return (fst v && snd v)
 check :: URLString -> Maybe Integer -> UrlOptions -> IO (Bool, Bool)
-check url expected_size = handle <$$> exists url
+check url expected_size = go <$$> exists url
   where
-	handle (False, _) = (False, False)
-	handle (True, Nothing) = (True, True)
-	handle (True, s) = case expected_size of
+	go (False, _) = (False, False)
+	go (True, Nothing) = (True, True)
+	go (True, s) = case expected_size of
 		Just _ -> (True, expected_size == s)
 		Nothing -> (True, True)
 
diff --git a/Utility/WebApp.hs b/Utility/WebApp.hs
index 0f3378a15..6bcfce919 100644
--- a/Utility/WebApp.hs
+++ b/Utility/WebApp.hs
@@ -38,10 +38,6 @@ import Data.Byteable
 #ifdef __ANDROID__
 import Data.Endian
 #endif
-#if defined(__ANDROID__) || defined (mingw32_HOST_OS)
-#else
-import Control.Exception (bracketOnError)
-#endif
 
 localhost :: HostName
 localhost = "localhost"