#171 in place edit

haskell-awk.cabal

@@ -77,6 +77,7 @@ Library
  build-depends: base >=4.6.0.1
  , bytestring
  , containers
+ , filepath
  , stringsearch >=0.3.6.4
  Default-Language: Haskell98
 

runtime/System/Console/Hawk/Args/Spec.hs

@@ -33,10 +33,15 @@ data InputSource
  | InputFile FilePath
  deriving (Show, Eq)
 
+data FileSink = FileSink
+ { outputFile :: FilePath
+ , backupFile :: Maybe FilePath
+ }
+ deriving (Show, Eq)
+
 data OutputSink
  = UseStdout
- -- OutputFile FilePath -- we might want to implement --in-place
- -- in the future
+ | OutputFile FileSink
  deriving (Show, Eq)
 
 data InputFormat

runtime/System/Console/Hawk/Runtime.hs

@@ -12,12 +12,12 @@ import Data.ByteString.Lazy.Char8 as B
 import Data.ByteString.Lazy.Search as Search
 import GHC.IO.Exception
 import System.IO
+import System.FilePath ((<.>))
 
 import System.Console.Hawk.Args.Spec
 import System.Console.Hawk.Representable
 import System.Console.Hawk.Runtime.Base
 
-
 data SomeRows = forall a. Rows a => SomeRows a
 
 processTable :: HawkRuntime -> ([[B.ByteString]] -> SomeRows) -> HawkIO ()
@@ -74,10 +74,14 @@ splitAtSeparator (Delimiter d) = Search.split d
 
 
 outputRows :: Rows a => OutputSpec -> a -> IO ()
-outputRows (OutputSpec _ spec) x = ignoringBrokenPipe $ do
+outputRows (OutputSpec out spec) x = ignoringBrokenPipe $ do
  let s = join' (toRows x)
- B.putStr s
- hFlush stdout
+ case out of
+ UseStdout -> B.putStr s >> hFlush stdout
+ OutputFile (FileSink f Nothing) -> B.writeFile (f <.> tmp) s
+ OutputFile (FileSink f (Just backup)) -> do
+ copyFile f backup
+ B.writeFile (f <.> tmp) s
  where
  join' = join (B.fromStrict $ recordDelimiter spec)
  toRows = repr (B.fromStrict $ fieldDelimiter spec)
@@ -86,6 +90,8 @@ outputRows (OutputSpec _ spec) x = ignoringBrokenPipe $ do
  join "\n" = B.unlines
  join sep = B.intercalate sep
 
+ copyFile i o = B.readFile i >>= \f -> B.writeFile o f
+
 -- Don't fret if stdout is closed early, that is the way of shell pipelines.
 ignoringBrokenPipe :: IO () -> IO ()
 ignoringBrokenPipe = handleJust isBrokenPipe $ \_ ->

runtime/System/Console/Hawk/Runtime/Base.hs

@@ -11,7 +11,6 @@ import Data.Typeable
 
 import System.Console.Hawk.Args.Spec
 
-
 data HawkRuntime = HawkRuntime
  { inputSpec :: InputSpec
  , outputSpec :: OutputSpec
@@ -21,3 +20,8 @@ data HawkRuntime = HawkRuntime
 -- reexport IO under a unique name
 newtype HawkIO a = HawkIO { runHawkIO :: IO a }
  deriving Typeable
+
+-- For redirecting stdout to a temporary file
+tmp :: FilePath
+tmp = "tmp"
+

src/System/Console/Hawk.hs

@@ -19,9 +19,12 @@ module System.Console.Hawk
  ) where
 
 
+import Control.Monad (when)
 import Control.Monad.Trans
 import Data.List
 import Language.Haskell.Interpreter
+import System.Directory (doesFileExist, renameFile)
+import System.FilePath ((<.>))
 
 import Control.Monad.Trans.Uncertain
 import Data.HaskellExpr.Eval
@@ -50,8 +53,16 @@ processSpec :: HawkSpec -> IO ()
 processSpec Help = help
 processSpec Version = putStrLn versionString
 processSpec (Eval e o) = myRunUncertainIO e $ processEvalSpec (contextSpec e) o (userExpr e)
-processSpec (Apply e i o) = myRunUncertainIO e $ processApplySpec (contextSpec e) i o (userExpr e)
-processSpec (Map e i o) = myRunUncertainIO e $ processMapSpec (contextSpec e) i o (userExpr e)
+processSpec (Apply e i o) = myRunUncertainIO e (processApplySpec (contextSpec e) i o (userExpr e)) >> overwrite o
+processSpec (Map e i o) = myRunUncertainIO e (processMapSpec (contextSpec e) i o (userExpr e)) >> overwrite o
+
+-- | Overwrites the input file with the temporary output file if it exists
+overwrite :: OutputSpec -> IO ()
+overwrite (OutputSpec (OutputFile (FileSink f _)) _) = do
+ fe <- doesFileExist tmpFile
+ when fe $ renameFile tmpFile f
+ where tmpFile = f <.> tmp
+overwrite _ = return ()
 
 -- | A version of `runUncertainIO` which detects poor error messages and improves them.
 myRunUncertainIO :: ExprSpec -> UncertainT IO () -> IO ()

src/System/Console/Hawk/Args/Option.hs

@@ -16,6 +16,8 @@ data HawkOption
  | RecordDelimiter
  | OutputFieldDelimiter
  | OutputRecordDelimiter
+ | InPlaceEdit
+ | InputFile
  | Version
  | Help
  | ContextDirectory
@@ -26,6 +28,9 @@ options :: [HawkOption]
 options = enumFrom minBound
 
 
+suffix :: OptionType
+suffix = nullable (Setting "suffix")
+
 delimiter :: OptionType
 delimiter = nullable (Setting "delim")
 
@@ -58,6 +63,8 @@ instance Option HawkOption where
  shortName RecordDelimiter = 'D'
  shortName OutputFieldDelimiter = 'o'
  shortName OutputRecordDelimiter = 'O'
+ shortName InPlaceEdit = 'i'
+ shortName InputFile = 'f'
  shortName Version = 'v'
  shortName Help = 'h'
  shortName ContextDirectory = 'c'
@@ -68,6 +75,8 @@ instance Option HawkOption where
  longName RecordDelimiter = "record-delimiter"
  longName OutputFieldDelimiter = "output-field-delim"
  longName OutputRecordDelimiter = "output-record-delim"
+ longName InPlaceEdit = "in-place"
+ longName InputFile = "file"
  longName Version = "version"
  longName Help = "help"
  longName ContextDirectory = "context-directory"
@@ -78,6 +87,9 @@ instance Option HawkOption where
  helpMsg RecordDelimiter = ["default '\\n'"]
  helpMsg OutputFieldDelimiter = ["default <field-delim>"]
  helpMsg OutputRecordDelimiter = ["default <record-delim>"]
+ helpMsg InPlaceEdit = ["overwrite <file>, optionally creating"
+ ,"a backup copy at <file><suffix>"]
+ helpMsg InputFile = ["input file for in place editing"]
  helpMsg Version = ["print version and exit"]
  helpMsg Help = ["this help"]
  helpMsg ContextDirectory = ["<ctx-dir> directory, default is"
@@ -89,6 +101,8 @@ instance Option HawkOption where
  optionType RecordDelimiter = delimiter
  optionType OutputFieldDelimiter = delimiter
  optionType OutputRecordDelimiter = delimiter
+ optionType InPlaceEdit = suffix
+ optionType InputFile = suffix
  optionType Version = flag
  optionType Help = flag
  optionType ContextDirectory = filePath

src/System/Console/Hawk/Args/Parse.hs

@@ -5,6 +5,7 @@ module System.Console.Hawk.Args.Parse (parseArgs) where
 import Control.Applicative
 import Data.Char (isSpace)
 import "mtl" Control.Monad.Trans
+import System.FilePath ((<.>))
 
 import Control.Monad.Trans.OptionParser
 import Control.Monad.Trans.Uncertain
@@ -17,12 +18,19 @@ import System.Console.Hawk.Context.Dir
 -- >>> let testP parser = runUncertainIO . runOptionParserT options parser
 
 
--- | (record separator, field separator)
-type CommonSeparators = (Separator, Separator)
+-- | Record separator, field separator, and input file
+-- is common to both output and input option parsing
+data CommonOptions = CommonOptions
+ { record :: Separator
+ , field :: Separator
+ , inputFile :: Maybe FilePath
+ }
 
--- | Extract '-D' and '-d'. We perform this step separately because those two
--- delimiters are used by both the input and output specs.
+-- | Extract '-D', '-d', and input file.
+-- We perform this step separately because those three
+-- options are used by both the input and output specs.
 -- 
+-- TODO: UPDATE TEST CASES
 -- >>> let test = testP commonSeparators
 -- 
 -- >>> test []
@@ -33,17 +41,17 @@ type CommonSeparators = (Separator, Separator)
 -- 
 -- >>> test ["-D|", "-d,"]
 -- (Delimiter "|",Delimiter ",")
-commonSeparators :: (Functor m, Monad m)
- => OptionParserT HawkOption m CommonSeparators
-commonSeparators = do
+commonOptions :: (Functor m, Monad m)
+ => OptionParserT HawkOption m CommonOptions
+commonOptions = do
  r <- lastSep Option.RecordDelimiter defaultRecordSeparator
  f <- lastSep Option.FieldDelimiter defaultFieldSeparator
- return (r, f)
+ file <- consumeLast Option.InputFile "" $ consumeNullable "" consumeString
+ return $ CommonOptions r f $ if null file then Nothing else Just file
  where
  lastSep opt def = consumeLast opt def consumeSep
  consumeSep = fmap Delimiter . Option.consumeDelimiter
 
-
 -- | The input delimiters have already been parsed, but we still need to
 -- interpret them and to determine the input source.
 -- 
@@ -72,19 +80,18 @@ commonSeparators = do
 -- InputFile "/etc/passwd"
 -- Records (Delimiter "\n") (Fields (Delimiter ":"))
 inputSpec :: (Functor m, Monad m)
- => CommonSeparators -> OptionParserT HawkOption m InputSpec
-inputSpec (rSep, fSep) = InputSpec <$> source <*> format
+ => CommonOptions -> OptionParserT HawkOption m InputSpec
+inputSpec opts = InputSpec <$> source <*> format
  where
- source = do
- r <- consumeExtra consumeString
- return $ case r of
- Nothing -> UseStdin
- Just f -> InputFile f
+ source = return $ maybe UseStdin InputFile file
  format = return streamFormat
  streamFormat | rSep == Delimiter "" = RawStream
- | otherwise  = Records rSep recordFormat
+ | otherwise = Records rSep recordFormat
  recordFormat | fSep == Delimiter "" = RawRecord
- | otherwise = Fields fSep
+ | otherwise = Fields fSep
+ rSep = record opts
+ fSep = field opts
+ file = inputFile opts
 
 -- | The output delimiters take priority over the input delimiters, regardless
 -- of the order in which they appear.
@@ -109,16 +116,33 @@ inputSpec (rSep, fSep) = InputSpec <$> source <*> format
 -- >>> test ["-o\t", "-d,", "-O|"]
 -- UseStdout
 -- ("|","\t")
+--
+-- TODO: write test cases for in-place edit
 outputSpec :: (Functor m, Monad m)
- => CommonSeparators -> OptionParserT HawkOption m OutputSpec
-outputSpec (r, f) = OutputSpec <$> sink <*> format
+ => CommonOptions -> OptionParserT HawkOption m OutputSpec
+outputSpec opts = OutputSpec <$> sink <*> format
  where
- sink = return UseStdout
- format = OutputFormat <$> record <*> field
- record = consumeLast Option.OutputRecordDelimiter r' Option.consumeDelimiter
- field = consumeLast Option.OutputFieldDelimiter f' Option.consumeDelimiter
- r' = fromSeparator r
- f' = fromSeparator f
+ sink = do
+ -- TODO: refactor with upcoming consumeNullable changes
+ backupSuffix <- consumeLast Option.InPlaceEdit "" $
+ consumeNullable "<none>" consumeString
+ case file of
+ Nothing -> if null backupSuffix
+ then return UseStdout
+ else fail "in-place edit requires input file"
+ Just file' -> if null backupSuffix
+ then return UseStdout
+ else if backupSuffix == "<none>"
+ then return $ OutputFile $ FileSink file' Nothing
+ else return $ OutputFile $ FileSink file'
+ (Just $ file' <.> backupSuffix)
+
+ format = OutputFormat <$> record' <*> field'
+ record' = consumeLast Option.OutputRecordDelimiter r' Option.consumeDelimiter
+ field' = consumeLast Option.OutputFieldDelimiter f' Option.consumeDelimiter
+ r' = fromSeparator $ record opts
+ f' = fromSeparator $ field opts
+ file = inputFile opts
 
 
 -- | The information we need in order to evaluate a user expression:
@@ -209,15 +233,15 @@ parseArgs args = runOptionParserT options parser args
  parser = do
  lift $ return () -- silence a warning
  cmd <- consumeExclusive assoc eval
- c <- commonSeparators
+ c <- commonOptions
  cmd c
  assoc = [ (Option.Help, help)
  , (Option.Version, version)
  , (Option.Apply, apply)
  , (Option.Map, map')
  ]
- 
- help, version, eval, apply, map' :: (Functor m,MonadIO m) => CommonSeparators
+
+ help, version, eval, apply, map' :: (Functor m,MonadIO m) => CommonOptions
  -> OptionParserT HawkOption m HawkSpec
  help _ = return Help
  version _ = return Version