content: -----------------------------------------------------------------------------
  -- |
  -- Module      :  Distribution.Simple.Bench
  -- Copyright   :  Johan Tibell 2011
  --
  -- Maintainer  :  cabal-devel@haskell.org
  -- Portability :  portable
  --
  -- This is the entry point into running the benchmarks in a built
  -- package. It performs the \"@.\/setup bench@\" action. It runs
  -- benchmarks designated in the package description.
  
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  module Distribution.Simple.Bench
      ( bench
      ) where
  
  import qualified Distribution.PackageDescription as PD
      ( PackageDescription(..), BuildInfo(buildable)
      , Benchmark(..), BenchmarkInterface(..), benchmarkType, hasBenchmarks )
  import Distribution.Simple.BuildPaths ( exeExtension )
  import Distribution.Simple.Compiler ( Compiler(..) )
  import Distribution.Simple.InstallDirs
      ( fromPathTemplate, initialPathTemplateEnv, PathTemplateVariable(..)
      , substPathTemplate , toPathTemplate, PathTemplate )
  import qualified Distribution.Simple.LocalBuildInfo as LBI
      ( LocalBuildInfo(..) )
  import Distribution.Simple.Setup ( BenchmarkFlags(..), fromFlag )
  import Distribution.Simple.UserHooks ( Args )
  import Distribution.Simple.Utils ( die, notice, rawSystemExitCode )
  import Distribution.Text
  
  import Control.Monad ( when, unless )
  import System.Exit ( ExitCode(..), exitFailure, exitWith )
  import System.Directory ( doesFileExist )
  import System.FilePath ( (</>), (<.>) )
  
  -- | Perform the \"@.\/setup bench@\" action.
  bench :: Args                    -- ^positional command-line arguments
        -> PD.PackageDescription   -- ^information from the .cabal file
        -> LBI.LocalBuildInfo      -- ^information from the configure step
        -> BenchmarkFlags          -- ^flags sent to benchmark
        -> IO ()
  bench args pkg_descr lbi flags = do
      let verbosity         = fromFlag $ benchmarkVerbosity flags
          benchmarkNames    = args
          pkgBenchmarks     = PD.benchmarks pkg_descr
          enabledBenchmarks = [ t | t <- pkgBenchmarks
                              , PD.benchmarkEnabled t
                              , PD.buildable (PD.benchmarkBuildInfo t) ]
  
          -- Run the benchmark
          doBench :: PD.Benchmark -> IO ExitCode
          doBench bm =
              case PD.benchmarkInterface bm of
                PD.BenchmarkExeV10 _ _ -> do
                    let cmd = LBI.buildDir lbi </> PD.benchmarkName bm
                              </> PD.benchmarkName bm <.> exeExtension
                        options = map (benchOption pkg_descr lbi bm) $
                                  benchmarkOptions flags
                        name = PD.benchmarkName bm
                    -- Check that the benchmark executable exists.
                    exists <- doesFileExist cmd
                    unless exists $ die $
                        "Error: Could not find benchmark program \""
                        ++ cmd ++ "\". Did you build the package first?"
  
                    notice verbosity $ startMessage name
                    -- This will redirect the child process
                    -- stdout/stderr to the parent process.
                    exitcode <- rawSystemExitCode verbosity cmd options
                    notice verbosity $ finishMessage name exitcode
                    return exitcode
  
                _ -> do
                    notice verbosity $ "No support for running "
                        ++ "benchmark " ++ PD.benchmarkName bm ++ " of type: "
                        ++ show (disp $ PD.benchmarkType bm)
                    exitFailure
  
      when (not $ PD.hasBenchmarks pkg_descr) $ do
          notice verbosity "Package has no benchmarks."
          exitWith ExitSuccess
  
      when (PD.hasBenchmarks pkg_descr && null enabledBenchmarks) $
          die $ "No benchmarks enabled. Did you remember to configure with "
                ++ "\'--enable-benchmarks\'?"
  
      bmsToRun <- case benchmarkNames of
              [] -> return enabledBenchmarks
              names -> flip mapM names $ \bmName ->
                  let benchmarkMap = zip enabledNames enabledBenchmarks
                      enabledNames = map PD.benchmarkName enabledBenchmarks
                      allNames = map PD.benchmarkName pkgBenchmarks
                  in case lookup bmName benchmarkMap of
                      Just t -> return t
                      _ | bmName `elem` allNames ->
                            die $ "Package configured with benchmark "
                                  ++ bmName ++ " disabled."
                        | otherwise -> die $ "no such benchmark: " ++ bmName
  
      let totalBenchmarks = length bmsToRun
      notice verbosity $ "Running " ++ show totalBenchmarks ++ " benchmarks..."
      exitcodes <- mapM doBench bmsToRun
      let allOk = totalBenchmarks == length (filter (== ExitSuccess) exitcodes)
      unless allOk exitFailure
    where
      startMessage name = "Benchmark " ++ name ++ ": RUNNING...\n"
      finishMessage name exitcode = "Benchmark " ++ name ++ ": "
                                 ++ (case exitcode of
                                          ExitSuccess -> "FINISH"
                                          ExitFailure _ -> "ERROR")
  
  
  -- TODO: This is abusing the notion of a 'PathTemplate'.  The result
  -- isn't neccesarily a path.
  benchOption :: PD.PackageDescription
              -> LBI.LocalBuildInfo
              -> PD.Benchmark
              -> PathTemplate
              -> String
  benchOption pkg_descr lbi bm template =
      fromPathTemplate $ substPathTemplate env template
    where
      env = initialPathTemplateEnv
            (PD.package pkg_descr) (compilerId $ LBI.compiler lbi) ++
            [(BenchmarkNameVar, toPathTemplate $ PD.benchmarkName bm)]
  