{-# LANGUAGE CPP, ScopedTypeVariables, LambdaCase #-}

-- | Defines a simple exception type and utilities to throw it. The
-- 'PlainGhcException' type is a subset of the 'Panic.GhcException'
-- type.  It omits the exception constructors that involve
-- pretty-printing via 'Outputable.SDoc'.
--
-- There are two reasons for this:
--
-- 1. To avoid import cycles / use of boot files. "Outputable" has
-- many transitive dependencies. To throw exceptions from these
-- modules, the functions here can be used without introducing import
-- cycles.
--
-- 2. To reduce the number of modules that need to be compiled to
-- object code when loading GHC into GHCi. See #13101
module PlainPanic
  ( PlainGhcException(..)
  , showPlainGhcException

  , panic, sorry, pgmError
  , cmdLineError, cmdLineErrorIO
  , assertPanic

  , progName
  ) where

#include "HsVersions.h"

import Config
import Exception
import GHC.Stack
import GhcPrelude
import System.Environment
import System.IO.Unsafe

-- | This type is very similar to 'Panic.GhcException', but it omits
-- the constructors that involve pretty-printing via
-- 'Outputable.SDoc'.  Due to the implementation of 'fromException'
-- for 'Panic.GhcException', this type can be caught as a
-- 'Panic.GhcException'.
--
-- Note that this should only be used for throwing exceptions, not for
-- catching, as 'Panic.GhcException' will not be converted to this
-- type when catching.
data PlainGhcException
  -- | Some other fatal signal (SIGHUP,SIGTERM)
  = PlainSignal Int

  -- | Prints the short usage msg after the error
  | PlainUsageError        String

  -- | A problem with the command line arguments, but don't print usage.
  | PlainCmdLineError      String

  -- | The 'impossible' happened.
  | PlainPanic             String

  -- | The user tickled something that's known not to work yet,
  --   but we're not counting it as a bug.
  | PlainSorry             String

  -- | An installation problem.
  | PlainInstallationError String

  -- | An error in the user's code, probably.
  | PlainProgramError      String

instance Exception PlainGhcException

instance Show PlainGhcException where
  showsPrec :: Int -> PlainGhcException -> ShowS
showsPrec Int
_ e :: PlainGhcException
e@(PlainProgramError String
_) = PlainGhcException -> ShowS
showPlainGhcException PlainGhcException
e
  showsPrec Int
_ e :: PlainGhcException
e@(PlainCmdLineError String
_) = String -> ShowS
showString String
"<command line>: " ShowS -> ShowS -> ShowS
forall b c a. (b -> c) -> (a -> b) -> a -> c
. PlainGhcException -> ShowS
showPlainGhcException PlainGhcException
e
  showsPrec Int
_ PlainGhcException
e = String -> ShowS
showString String
progName ShowS -> ShowS -> ShowS
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> ShowS
showString String
": " ShowS -> ShowS -> ShowS
forall b c a. (b -> c) -> (a -> b) -> a -> c
. PlainGhcException -> ShowS
showPlainGhcException PlainGhcException
e

-- | The name of this GHC.
progName :: String
progName :: String
progName = IO String -> String
forall a. IO a -> a
unsafePerformIO (IO String
getProgName)
{-# NOINLINE progName #-}

-- | Short usage information to display when we are given the wrong cmd line arguments.
short_usage :: String
short_usage :: String
short_usage = String
"Usage: For basic information, try the `--help' option."

-- | Append a description of the given exception to this string.
showPlainGhcException :: PlainGhcException -> ShowS
showPlainGhcException :: PlainGhcException -> ShowS
showPlainGhcException =
  \case
    PlainSignal Int
n -> String -> ShowS
showString String
"signal: " ShowS -> ShowS -> ShowS
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Int -> ShowS
forall a. Show a => a -> ShowS
shows Int
n
    PlainUsageError String
str -> String -> ShowS
showString String
str ShowS -> ShowS -> ShowS
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Char -> ShowS
showChar Char
'\n' ShowS -> ShowS -> ShowS
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> ShowS
showString String
short_usage
    PlainCmdLineError String
str -> String -> ShowS
showString String
str
    PlainPanic String
s -> ShowS -> ShowS
panicMsg (String -> ShowS
showString String
s)
    PlainSorry String
s -> ShowS -> ShowS
sorryMsg (String -> ShowS
showString String
s)
    PlainInstallationError String
str -> String -> ShowS
showString String
str
    PlainProgramError String
str -> String -> ShowS
showString String
str
  where
    sorryMsg :: ShowS -> ShowS
    sorryMsg :: ShowS -> ShowS
sorryMsg ShowS
s =
        String -> ShowS
showString String
"sorry! (unimplemented feature or known bug)\n"
      ShowS -> ShowS -> ShowS
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> ShowS
showString (String
"  (GHC version " String -> ShowS
forall a. [a] -> [a] -> [a]
++ String
cProjectVersion String -> ShowS
forall a. [a] -> [a] -> [a]
++ String
":\n\t")
      ShowS -> ShowS -> ShowS
forall b c a. (b -> c) -> (a -> b) -> a -> c
. ShowS
s ShowS -> ShowS -> ShowS
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> ShowS
showString String
"\n"

    panicMsg :: ShowS -> ShowS
    panicMsg :: ShowS -> ShowS
panicMsg ShowS
s =
        String -> ShowS
showString String
"panic! (the 'impossible' happened)\n"
      ShowS -> ShowS -> ShowS
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> ShowS
showString (String
"  (GHC version " String -> ShowS
forall a. [a] -> [a] -> [a]
++ String
cProjectVersion String -> ShowS
forall a. [a] -> [a] -> [a]
++ String
":\n\t")
      ShowS -> ShowS -> ShowS
forall b c a. (b -> c) -> (a -> b) -> a -> c
. ShowS
s ShowS -> ShowS -> ShowS
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> ShowS
showString String
"\n\n"
      ShowS -> ShowS -> ShowS
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> ShowS
showString String
"Please report this as a GHC bug:  https://www.haskell.org/ghc/reportabug\n"

throwPlainGhcException :: PlainGhcException -> a
throwPlainGhcException :: PlainGhcException -> a
throwPlainGhcException = PlainGhcException -> a
forall a e. Exception e => e -> a
Exception.throw

-- | Panics and asserts.
panic, sorry, pgmError :: String -> a
panic :: String -> a
panic    String
x = IO a -> a
forall a. IO a -> a
unsafeDupablePerformIO (IO a -> a) -> IO a -> a
forall a b. (a -> b) -> a -> b
$ do
   [String]
stack <- Ptr CostCentreStack -> IO [String]
ccsToStrings (Ptr CostCentreStack -> IO [String])
-> IO (Ptr CostCentreStack) -> IO [String]
forall (m :: * -> *) a b. Monad m => (a -> m b) -> m a -> m b
=<< String -> IO (Ptr CostCentreStack)
forall dummy. dummy -> IO (Ptr CostCentreStack)
getCurrentCCS String
x
   if [String] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null [String]
stack
      then PlainGhcException -> IO a
forall a. PlainGhcException -> a
throwPlainGhcException (String -> PlainGhcException
PlainPanic String
x)
      else PlainGhcException -> IO a
forall a. PlainGhcException -> a
throwPlainGhcException (String -> PlainGhcException
PlainPanic (String
x String -> ShowS
forall a. [a] -> [a] -> [a]
++ Char
'\n' Char -> ShowS
forall a. a -> [a] -> [a]
: [String] -> String
renderStack [String]
stack))

sorry :: String -> a
sorry    String
x = PlainGhcException -> a
forall a. PlainGhcException -> a
throwPlainGhcException (String -> PlainGhcException
PlainSorry String
x)
pgmError :: String -> a
pgmError String
x = PlainGhcException -> a
forall a. PlainGhcException -> a
throwPlainGhcException (String -> PlainGhcException
PlainProgramError String
x)

cmdLineError :: String -> a
cmdLineError :: String -> a
cmdLineError = IO a -> a
forall a. IO a -> a
unsafeDupablePerformIO (IO a -> a) -> (String -> IO a) -> String -> a
forall b c a. (b -> c) -> (a -> b) -> a -> c
. String -> IO a
forall a. String -> IO a
cmdLineErrorIO

cmdLineErrorIO :: String -> IO a
cmdLineErrorIO :: String -> IO a
cmdLineErrorIO String
x = do
  [String]
stack <- Ptr CostCentreStack -> IO [String]
ccsToStrings (Ptr CostCentreStack -> IO [String])
-> IO (Ptr CostCentreStack) -> IO [String]
forall (m :: * -> *) a b. Monad m => (a -> m b) -> m a -> m b
=<< String -> IO (Ptr CostCentreStack)
forall dummy. dummy -> IO (Ptr CostCentreStack)
getCurrentCCS String
x
  if [String] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null [String]
stack
    then PlainGhcException -> IO a
forall a. PlainGhcException -> a
throwPlainGhcException (String -> PlainGhcException
PlainCmdLineError String
x)
    else PlainGhcException -> IO a
forall a. PlainGhcException -> a
throwPlainGhcException (String -> PlainGhcException
PlainCmdLineError (String
x String -> ShowS
forall a. [a] -> [a] -> [a]
++ Char
'\n' Char -> ShowS
forall a. a -> [a] -> [a]
: [String] -> String
renderStack [String]
stack))

-- | Throw a failed assertion exception for a given filename and line number.
assertPanic :: String -> Int -> a
assertPanic :: String -> Int -> a
assertPanic String
file Int
line =
  AssertionFailed -> a
forall a e. Exception e => e -> a
Exception.throw (String -> AssertionFailed
Exception.AssertionFailed
           (String
"ASSERT failed! file " String -> ShowS
forall a. [a] -> [a] -> [a]
++ String
file String -> ShowS
forall a. [a] -> [a] -> [a]
++ String
", line " String -> ShowS
forall a. [a] -> [a] -> [a]
++ Int -> String
forall a. Show a => a -> String
show Int
line))