From e6d741af79b04f9c2c09f73eb28d91f924c6d291 Mon Sep 17 00:00:00 2001
From: Joey Hess <joeyh@joeyh.name>
Date: Wed, 18 Nov 2020 14:54:02 -0400
Subject: [PATCH] finish conversion to hGetLineUntilExitOrEOF

started in aafae46bcbb2a9533364b65be5fc05b379898aa1
---
 Utility/Metered.hs | 24 +++++++++++-------------
 Utility/Process.hs |  6 +++---
 2 files changed, 14 insertions(+), 16 deletions(-)

diff --git a/Utility/Metered.hs b/Utility/Metered.hs
index d39e39bfaf..888e7e1416 100644
--- a/Utility/Metered.hs
+++ b/Utility/Metered.hs
@@ -290,12 +290,11 @@ commandMeterExitCode' progressparser oh mmeter meterupdate cmd params mkprocess
 							meterupdate bytes
 						feedprogress sendtotalsize' bytes buf' h
 
-	handlestderr ph h = unlessM (hIsEOF h) $ do
-		cancelOnExit ph (hGetLine h) >>= \case
-			Just l -> do
-				stderrHandler oh l
-				handlestderr ph h
-			Nothing -> return ()
+	handlestderr ph h = hGetLineUntilExitOrEOF ph h >>= \case
+		Just l -> do
+			stderrHandler oh l
+			handlestderr ph h
+		Nothing -> return ()
 
 {- Runs a command, that may display one or more progress meters on
  - either stdout or stderr, and prevents the meters from being displayed.
@@ -323,13 +322,12 @@ demeterCommandEnv oh cmd params environ = do
  - beginning of the line when updating a progress display).
  -}
 avoidProgress :: Bool -> ProcessHandle -> Handle -> (String -> IO ()) -> IO ()
-avoidProgress doavoid ph h emitter = unlessM (hIsEOF h) $
-	cancelOnExit ph (hGetLine h) >>= \case
-		Just s -> do
-			unless (doavoid && '\r' `elem` s) $
-				emitter s
-			avoidProgress doavoid ph h emitter
-		Nothing -> return ()
+avoidProgress doavoid ph h emitter = hGetLineUntilExitOrEOF ph h >>= \case
+	Just s -> do
+		unless (doavoid && '\r' `elem` s) $
+			emitter s
+		avoidProgress doavoid ph h emitter
+	Nothing -> return ()
 
 outputFilter
 	:: FilePath
diff --git a/Utility/Process.hs b/Utility/Process.hs
index 7552264710..1348e9ee92 100644
--- a/Utility/Process.hs
+++ b/Utility/Process.hs
@@ -231,9 +231,9 @@ cleanupProcess (mb_stdin, mb_stdout, mb_stderr, pid) = do
 	void $ waitForProcess pid
 #endif
 
-{- | Like hGetLine, reads a line from the Handle. If the Handle is already
- - closed, returns Nothing. If the process exits without writing a line,
- - also returns Nothing.
+{- | Like hGetLine, reads a line from the Handle. Returns Nothing if end of
+ - file is reached, or if the process has exited and there is nothing more
+ - buffered to read from the handle.
  -
  - This is useful to protect against situations where the process might
  - have transferred the handle being read to another process, and so