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| author | Ben Gamari <ben@smart-cactus.org> | 2020-03-30 10:43:50 -0400 |
|---|---|---|
| committer | Ben Gamari <ben@well-typed.com> | 2020-03-31 12:47:54 -0400 |
| commit | 4066f4e9c2f54770147f1d63d55bbb300edd866c (patch) | |
| tree | 4b4dcb8953e44fe1f62b7586db57d6ae7723fe04 | |
| parent | 4b9c586472bf99425f7bbcf346472d7c54f05028 (diff) | |
| download | haskell-wip/T17922.tar.gz | |
Session: Memoize stderrSupportsAnsiColorswip/T17922
Not only is this a reasonable efficiency measure but it avoids making
reentrant calls into ncurses, which is not thread-safe. See #17922.
| -rw-r--r-- | compiler/GHC/Driver/Session.hs | 3 | ||||
| -rw-r--r-- | compiler/main/SysTools/Terminal.hs | 12 |
2 files changed, 11 insertions, 4 deletions
diff --git a/compiler/GHC/Driver/Session.hs b/compiler/GHC/Driver/Session.hs index 8e66fef327..f500aa3501 100644 --- a/compiler/GHC/Driver/Session.hs +++ b/compiler/GHC/Driver/Session.hs @@ -1253,7 +1253,6 @@ initDynFlags dflags = do `catchIOError` \_ -> return False ghcNoUnicodeEnv <- lookupEnv "GHC_NO_UNICODE" let useUnicode' = isNothing ghcNoUnicodeEnv && canUseUnicode - canUseColor <- stderrSupportsAnsiColors maybeGhcColorsEnv <- lookupEnv "GHC_COLORS" maybeGhcColoursEnv <- lookupEnv "GHC_COLOURS" let adjustCols (Just env) = Col.parseScheme env @@ -1270,7 +1269,7 @@ initDynFlags dflags = do nextWrapperNum = wrapperNum, useUnicode = useUnicode', useColor = useColor', - canUseColor = canUseColor, + canUseColor = stderrSupportsAnsiColors, colScheme = colScheme', rtldInfo = refRtldInfo, rtccInfo = refRtccInfo diff --git a/compiler/main/SysTools/Terminal.hs b/compiler/main/SysTools/Terminal.hs index d1262db531..162dd32010 100644 --- a/compiler/main/SysTools/Terminal.hs +++ b/compiler/main/SysTools/Terminal.hs @@ -18,6 +18,8 @@ import qualified Graphics.Win32 as Win32 import qualified System.Win32 as Win32 #endif +import System.IO.Unsafe + #if defined(mingw32_HOST_OS) && !defined(WINAPI) # if defined(i386_HOST_ARCH) # define WINAPI stdcall @@ -28,9 +30,15 @@ import qualified System.Win32 as Win32 # endif #endif +-- | Does the controlling terminal support ANSI color sequences? +-- This memoized to avoid thread-safety issues in ncurses (see #17922). +stderrSupportsAnsiColors :: Bool +stderrSupportsAnsiColors = unsafePerformIO stderrSupportsAnsiColors' +{-# NOINLINE stderrSupportsAnsiColors #-} + -- | Check if ANSI escape sequences can be used to control color in stderr. -stderrSupportsAnsiColors :: IO Bool -stderrSupportsAnsiColors = do +stderrSupportsAnsiColors' :: IO Bool +stderrSupportsAnsiColors' = do #if defined(MIN_VERSION_terminfo) stderr_available <- queryTerminal stdError if stderr_available then |