add back debug logging

Make Utility.Process wrap the parts of System.Process that I use,
and add debug logging to them.

Also wrote some higher-level code that allows running an action
with handles to a processes stdin or stdout (or both), and checking
its exit status, all in a single function call.

As a bonus, the debug logging now indicates whether the process
is being run to read from it, feed it data, chat with it (writing and
reading), or just call it for its side effect.

1 files changed, 5 insertions, 4 deletions

diff --git a/Utility/Lsof.hs b/Utility/Lsof.hs
index ebd273b2e..ce6a16283 100644
--- a/Utility/Lsof.hs
+++ b/Utility/Lsof.hs
@@ -12,7 +12,6 @@ module Utility.Lsof where
 import Common
 
 import System.Posix.Types
-import System.Process
 
 data LsofOpenMode = OpenReadWrite | OpenReadOnly | OpenWriteOnly | OpenUnknown
 	deriving (Show, Eq)
@@ -34,9 +33,11 @@ queryDir path = query ["+d", path]
  - Note: If lsof is not available, this always returns [] !
  -}
 query :: [String] -> IO [(FilePath, LsofOpenMode, ProcessInfo)]
-query opts = do
-	(_, s, _) <- readProcessWithExitCode "lsof" ("-F0can" : opts) []
-	return $ parse s
+query opts =
+	withHandle StdoutHandle (createProcessChecked checkSuccessProcess) p $ \h -> do
+		parse <$> hGetContentsStrict h
+	where
+		p = proc "lsof" ("-F0can" : opts)
 
 {- Parsing null-delimited output like:
  -