diff --git a/LICENSE b/LICENSE new file mode 100644 --- /dev/null +++ b/LICENSE @@ -0,0 +1,674 @@ + GNU GENERAL PUBLIC LICENSE + Version 3, 29 June 2007 + + Copyright (C) 2007 Free Software Foundation, Inc. + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The GNU General Public License is a free, copyleft license for +software and other kinds of works. + + The licenses for most software and other practical works are designed +to take away your freedom to share and change the works. By contrast, +the GNU General Public License is intended to guarantee your freedom to +share and change all versions of a program--to make sure it remains free +software for all its users. We, the Free Software Foundation, use the +GNU General Public License for most of our software; it applies also to +any other work released this way by its authors. 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If not, see . + +Also add information on how to contact you by electronic and paper mail. + + If the program does terminal interaction, make it output a short +notice like this when it starts in an interactive mode: + + Copyright (C) + This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands `show w' and `show c' should show the appropriate +parts of the General Public License. Of course, your program's commands +might be different; for a GUI interface, you would use an "about box". + + You should also get your employer (if you work as a programmer) or school, +if any, to sign a "copyright disclaimer" for the program, if necessary. +For more information on this, and how to apply and follow the GNU GPL, see +. + + The GNU General Public License does not permit incorporating your program +into proprietary programs. If your program is a subroutine library, you +may consider it more useful to permit linking proprietary applications with +the library. If this is what you want to do, use the GNU Lesser General +Public License instead of this License. But first, please read +. diff --git a/Setup.hs b/Setup.hs new file mode 100644 --- /dev/null +++ b/Setup.hs @@ -0,0 +1,2 @@ +import Distribution.Simple +main = defaultMain diff --git a/microaeson.cabal b/microaeson.cabal new file mode 100644 --- /dev/null +++ b/microaeson.cabal @@ -0,0 +1,88 @@ +cabal-version: 2.0 +name: microaeson +version: 0.1.0.0 + +synopsis: A tiny JSON library with light dependency footprint +license: GPL-3 +license-file: LICENSE +author: Herbert Valerio Riedel +maintainer: hvr@gnu.org +category: Text, Web, JSON +build-type: Simple +description: { + +@microaeson@ aims to provide a [RFC 8259](https://tools.ietf.org/html/rfc8259) compliant JavaScript Object Notation (JSON) implementation. + +The [microaeson](https://hackage.haskell.org/package/microaeson) package provides a smaller subset of the [aeson](https://hackage.haskell.org/package/aeson) API with less dependencies and a simpler implementation. +. +The API is designed in such a way to allow to easily convert client code written against @microaeson@'s API to use the full [aeson](https://hackage.haskell.org/package/aeson) API. + +} + +source-repository head + type: git + location: https://github.com/hvr/microaeson.git + +library + default-language: Haskell2010 + other-extensions: CPP + DeriveDataTypeable + DeriveGeneric + FlexibleInstances + GeneralizedNewtypeDeriving + MagicHash + OverloadedStrings + + hs-source-dirs: src + + exposed-modules: Data.Aeson.Micro + other-modules: Data.Aeson.Micro.Parser + Data.Aeson.Micro.Scanner + + build-depends: array ^>= 0.5.1.0 + , base ^>= 4.8.0.0 + || ^>= 4.9.0.0 + || ^>= 4.10.0.0 + || ^>= 4.11.0.0 + , bytestring ^>= 0.10.6.0 + , containers ^>= 0.5.6.2 + , deepseq ^>= 1.4.1.1 + , text ^>= 1.2.2.2 + + build-tools: alex ^>= 3.2.0 + + ghc-options: -Wall + + if impl(ghc >= 8.0) + ghc-options: -Wcompat -Wnoncanonical-monad-instances -Wnoncanonical-monadfail-instances + +test-suite microaeson + default-language: Haskell2010 + + hs-source-dirs: src-tests + main-is: tests.hs + + type: exitcode-stdio-1.0 + + -- internal dependency + build-depends: microaeson + + -- constraints inherited via lib:microaeson component + build-depends: base + , bytestring + , containers + + -- dependencies requiring constraints + build-depends: aeson ^>= 1.3.1.0 + , QuickCheck ^>= 2.11.3 + , quickcheck-instances ^>= 0.3.16 + , tasty ^>= 1.0.1.1 + , tasty-quickcheck ^>= 0.10 + , text ^>= 1.2.2.2 + , unordered-containers ^>= 0.2.8.0 + , vector ^>= 0.12.0.1 + + ghc-options: -Wall + + if impl(ghc >= 8.0) + ghc-options: -Wcompat -Wnoncanonical-monad-instances -Wnoncanonical-monadfail-instances diff --git a/src-tests/tests.hs b/src-tests/tests.hs new file mode 100644 --- /dev/null +++ b/src-tests/tests.hs @@ -0,0 +1,72 @@ +{-# OPTIONS_GHC -fno-warn-orphans #-} + +module Main where + +import qualified Data.HashMap.Strict as HM +import qualified Data.Map.Strict as Map +import qualified Data.Vector as V + +import Test.Tasty +import Test.Tasty.QuickCheck as QC +import Test.QuickCheck.Instances () + +import qualified Data.Aeson as REF +import qualified Data.Aeson.Micro as IUT + +main :: IO () +main = defaultMain tests + +tests :: TestTree +tests = testGroup "Tests" [qcProps] + where + qcProps = testGroup "QC" + [ QC.testProperty "roundtrip(ref/ref)" $ + \x -> (fmap fromAeson . REF.decode . REF.encode . toAeson) x == Just x + + , QC.testProperty "roundtrip(ref/iut)" $ + \x -> (fmap fromAeson . REF.decode . IUT.encode) x == Just x + + , QC.testProperty "roundtrip(iut/ref)" $ + \x -> (IUT.decode . REF.encode . toAeson) x == Just x + + , QC.testProperty "roundtrip(iut/iut)" $ + \x -> (IUT.decodeStrict . IUT.encodeStrict) x == Just (x :: IUT.Value) + ] + + +instance Arbitrary IUT.Value where + arbitrary = sized value + where + value 0 = oneof [ IUT.String <$> arbitrary + , IUT.Number <$> arbitrary + , IUT.Bool <$> arbitrary + , pure IUT.Null + ] + value n | n>0 + = oneof [ IUT.String <$> arbitrary + , IUT.Number <$> arbitrary + , IUT.Bool <$> arbitrary + , pure IUT.Null + , IUT.Array <$> resize ((10*n) `div` 14) arbitrary + , IUT.Object <$> resize ((10*n) `div` 14) arbitrary + ] + | otherwise = pure IUT.Null + + +toAeson :: IUT.Value -> REF.Value +toAeson j = case j of + IUT.String t -> REF.String t + IUT.Number n -> REF.toJSON n + IUT.Bool b -> REF.Bool b + IUT.Null -> REF.Null + IUT.Array l -> REF.Array (V.fromList (map toAeson l)) + IUT.Object m -> REF.object [ (k, toAeson v) | (k,v) <- Map.toList m ] + +fromAeson :: REF.Value -> IUT.Value +fromAeson j = case j of + REF.String t -> IUT.String t + REF.Bool b -> IUT.Bool b + REF.Null -> IUT.Null + REF.Number s -> IUT.Number (realToFrac s) + REF.Array v -> IUT.Array (map fromAeson (V.toList v)) + REF.Object m -> IUT.object [ (k, fromAeson v) | (k,v) <- HM.toList m ] diff --git a/src/Data/Aeson/Micro.hs b/src/Data/Aeson/Micro.hs new file mode 100644 --- /dev/null +++ b/src/Data/Aeson/Micro.hs @@ -0,0 +1,540 @@ +{-# LANGUAGE DeriveDataTypeable #-} +{-# LANGUAGE DeriveGeneric #-} +{-# LANGUAGE FlexibleInstances #-} +{-# LANGUAGE GeneralizedNewtypeDeriving #-} +{-# LANGUAGE OverloadedStrings #-} + +-- | Minimal JavaScript Object Notation (JSON) support as per . +-- +-- This API provides a subset (with a couple of divergences; see below) of +-- [aeson API](https://hackage.haskell.org/package/aeson/docs/Data-Aeson.html) +-- but puts the emphasis on simplicity rather than performance and features. +-- +-- The 'ToJSON' and 'FromJSON' instances are intended to have an encoding +-- compatible with @aeson@'s encoding. +-- +-- == Limitations and divergences from @aeson@'s API +-- +-- In order to reduce the dependency footprint and keep the code +-- simpler, the following divergences from the @aeson@ API have to be +-- made: +-- +-- * There are no `FromJSON`/`ToJSON` instances for `Char` & `String`. +-- * The type synonym (& the constructor of the same name) 'Object' uses @containers@'s 'Map.Map' rather than a 'HashMap' @unordered-containers@. +-- * 'Array' is represented by an ordinary list rather than a 'Vector' from the @vector@ package. +-- * 'Number' uses 'Double' instead of 'Scientific' +-- +module Data.Aeson.Micro + ( -- * Core JSON types + Value(..) + , Object + , Pair + + -- ** Constructors + , (.=) + , object + , emptyArray + , emptyObject + + -- ** Accessors + , (.:) + , (.:?) + , (.:!) + , (.!=) + + -- * Encoding and decoding + , encode + , encodeStrict + , encodeToBuilder + + , decodeStrict + , decode + + , decodeStrictN + + -- * Prism-style parsers + , withObject + , withText + , withArray + , withNumber + , withBool + + -- * Type conversion + , FromJSON(parseJSON) + , Parser, parseMaybe + , ToJSON(toJSON) + + ) where + +import Control.Monad +import Data.Char +import Data.Data (Data) +import Data.Int +import Data.List +import Data.Monoid +import Data.String +import Data.Typeable (Typeable) +import Data.Word +import GHC.Generics (Generic) + +import Control.DeepSeq +import qualified Data.ByteString as BS +import Data.ByteString.Builder (Builder) +import qualified Data.ByteString.Builder as BB +import qualified Data.ByteString.Lazy as BS.Lazy +import qualified Data.Map.Strict as Map +import Data.Text (Text) +import qualified Data.Text as T +import qualified Data.Text.Encoding as T +import qualified Data.Text.Lazy as TL + +import Data.Aeson.Micro.Parser +import Data.Aeson.Micro.Scanner (Lexeme (..), scanLexemes) + +-- TODO: We may want to replace 'String' with 'Text' or 'ByteString' + +-- | A JSON value represented as a Haskell value. +data Value = Object !Object + | Array [Value] + | String !Text + | Number !Double + | Bool !Bool + | Null + deriving (Eq, Read, Show, Generic, Data, Typeable) + +instance NFData Value + +instance IsString Value where + fromString = String . fromString + +-- | A key\/value pair for an 'Object' +type Pair = (Text, Value) + +-- | A JSON \"object\" (key/value map). +type Object = Map.Map Text Value + +infixr 8 .= + +-- | A key-value pair for encoding a JSON object. +(.=) :: ToJSON v => Text -> v -> Pair +k .= v = (k, toJSON v) + +-- | Create a 'Value' from a list of name\/value 'Pair's. +object :: [Pair] -> Value +object = Object . Map.fromList + +-- | The empty JSON 'Object' (i.e. @{}@). +emptyObject :: Value +emptyObject = Object mempty + +-- | The empty JSON 'Array' (i.e. @[]@). +emptyArray :: Value +emptyArray = Array mempty + +---------------------------------------------------------------------------- + +(.:) :: FromJSON a => Object -> Text -> Parser a +m .: k = maybe (pfail "key not found") parseJSON (Map.lookup k m) + +(.:?) :: FromJSON a => Object -> Text -> Parser (Maybe a) +m .:? k = maybe (pure Nothing) parseJSON (Map.lookup k m) + +(.:!) :: FromJSON a => Object -> Text -> Parser (Maybe a) +m .:! k = maybe (pure Nothing) (fmap Just . parseJSON) (Map.lookup k m) + +(.!=) :: Parser (Maybe a) -> a -> Parser a +mv .!= def = fmap (maybe def id) mv + +---------------------------------------------------------------------------- + +-- | A type that can be converted to JSON. +class ToJSON a where + -- | Convert a Haskell value to a JSON-friendly intermediate type. + toJSON :: a -> Value + +instance ToJSON () where + toJSON () = Array [] + +instance ToJSON Value where + toJSON = id + +instance ToJSON Bool where + toJSON = Bool + +instance ToJSON a => ToJSON [a] where + toJSON = Array . map toJSON + +instance ToJSON v => ToJSON (Map.Map Text v) where + toJSON = Object . Map.map toJSON + +instance ToJSON a => ToJSON (Maybe a) where + toJSON Nothing = Null + toJSON (Just a) = toJSON a + +instance (ToJSON a,ToJSON b) => ToJSON (a,b) where + toJSON (a,b) = Array [toJSON a, toJSON b] + +instance (ToJSON a,ToJSON b,ToJSON c) => ToJSON (a,b,c) where + toJSON (a,b,c) = Array [toJSON a, toJSON b, toJSON c] + +instance (ToJSON a,ToJSON b,ToJSON c, ToJSON d) => ToJSON (a,b,c,d) where + toJSON (a,b,c,d) = Array [toJSON a, toJSON b, toJSON c, toJSON d] + +instance ToJSON Text where + toJSON = String + +instance ToJSON TL.Text where + toJSON = toJSON . TL.toStrict + +instance ToJSON Float where + toJSON = Number . realToFrac + +instance ToJSON Double where + toJSON = Number + +instance ToJSON Int where toJSON = Number . realToFrac +instance ToJSON Int8 where toJSON = Number . realToFrac +instance ToJSON Int16 where toJSON = Number . realToFrac +instance ToJSON Int32 where toJSON = Number . realToFrac + +instance ToJSON Word where toJSON = Number . realToFrac +instance ToJSON Word8 where toJSON = Number . realToFrac +instance ToJSON Word16 where toJSON = Number . realToFrac +instance ToJSON Word32 where toJSON = Number . realToFrac + +-- | Possibly lossy due to conversion to 'Double' +instance ToJSON Int64 where toJSON = Number . realToFrac + +-- | Possibly lossy due to conversion to 'Double' +instance ToJSON Word64 where toJSON = Number . realToFrac + +-- | Possibly lossy due to conversion to 'Double' +instance ToJSON Integer where toJSON = Number . fromInteger + +------------------------------------------------------------------------------ +-- 'BB.Builder'-based encoding + +-- | Serialise value as JSON/UTF-8-encoded strict 'BS.ByteString' +encodeStrict :: ToJSON a => a -> BS.ByteString +encodeStrict = BS.Lazy.toStrict . encode + +-- | Serialise value as JSON/UTF-8-encoded lazy 'BS.Lazy.ByteString' +encode :: ToJSON a => a -> BS.Lazy.ByteString +encode = BB.toLazyByteString . encodeToBuilder + +-- | Serialise value as JSON/UTF8-encoded 'Builder' +encodeToBuilder :: ToJSON a => a -> Builder +encodeToBuilder = encodeValueBB . toJSON + +encodeValueBB :: Value -> Builder +encodeValueBB jv = case jv of + Bool True -> "true" + Bool False -> "false" + Null -> "null" + Number n + | isNaN n || isInfinite n -> encodeValueBB Null + | Just i <- doubleToInt64 n -> BB.int64Dec i + | otherwise -> BB.doubleDec n + Array a -> encodeArrayBB a + String s -> encodeStringBB s + Object o -> encodeObjectBB o + +encodeArrayBB :: [Value] -> Builder +encodeArrayBB [] = "[]" +encodeArrayBB jvs = BB.char8 '[' <> go jvs <> BB.char8 ']' + where + go = Data.Monoid.mconcat . intersperse (BB.char8 ',') . map encodeValueBB + +encodeObjectBB :: Object -> Builder +encodeObjectBB m + | Map.null m = "{}" + | otherwise = BB.char8 '{' <> go jvs <> BB.char8 '}' + where + jvs = Map.toList m + go = Data.Monoid.mconcat . intersperse (BB.char8 ',') . map encPair + encPair (l,x) = encodeStringBB l <> BB.char8 ':' <> encodeValueBB x + +encodeStringBB :: Text -> Builder +encodeStringBB str = BB.char8 '"' <> go str <> BB.char8 '"' + where + go = T.encodeUtf8Builder . escapeText + +------------------------------------------------------------------------------ +-- helpers + +-- | Try to convert 'Double' into 'Int64', return 'Nothing' if not +-- representable loss-free as integral 'Int64' value. +doubleToInt64 :: Double -> Maybe Int64 +doubleToInt64 x + | fromInteger x' == x + , x' <= toInteger (maxBound :: Int64) + , x' >= toInteger (minBound :: Int64) + = Just (fromIntegral x') + | otherwise = Nothing + where + x' = round x + +-- | Minimally escape a 'String' in accordance with [RFC 8259, "7. Strings"](https://tools.ietf.org/html/rfc8259#section-7) +escapeText :: Text -> Text +escapeText s + | not (T.any needsEscape s) = s + | otherwise = (T.pack . escape . T.unpack) s + where + escape [] = [] + escape (x:xs) = case x of + '\\' -> '\\':'\\':escape xs + '"' -> '\\':'"':escape xs + '\b' -> '\\':'b':escape xs + '\f' -> '\\':'f':escape xs + '\n' -> '\\':'n':escape xs + '\r' -> '\\':'r':escape xs + '\t' -> '\\':'t':escape xs + c | ord c < 0x10 -> '\\':'u':'0':'0':'0':intToDigit (ord c):escape xs + | ord c < 0x20 -> '\\':'u':'0':'0':'1':intToDigit (ord c - 0x10):escape xs + | otherwise -> c : escape xs + + -- unescaped = %x20-21 / %x23-5B / %x5D-10FFFF + needsEscape c = ord c < 0x20 || c `elem` ['\\','"'] + +---------------------------------------------------------------------------- +---------------------------------------------------------------------------- + +-- | JSON Parser 'Monad' used by 'FromJSON' +newtype Parser a = P { unP :: Maybe a } + deriving (Functor,Applicative,Monad) + +-- | Run 'Parser'. +-- +-- A common use-case is @'parseMaybe' 'parseJSON'@. +parseMaybe :: (a -> Parser b) -> a -> Maybe b +parseMaybe m v = unP (m v) + +pfail :: String -> Parser a +pfail _ = P Nothing + +-- | A type that JSON can be deserialised into +class FromJSON a where + -- | Decode a JSON value into a native Haskell type + parseJSON :: Value -> Parser a + +instance FromJSON Value where + parseJSON = pure + +instance FromJSON Bool where + parseJSON = withBool "Bool" pure + +instance FromJSON Text where + parseJSON = withText "Text" pure + +instance FromJSON TL.Text where + parseJSON = withText "Text" (pure . TL.fromStrict) + +instance FromJSON a => FromJSON [a] where + parseJSON = withArray "[a]" (mapM parseJSON) + +instance FromJSON Double where + parseJSON Null = pure (0/0) + parseJSON j = withNumber "Double" pure j + +instance FromJSON Float where + parseJSON Null = pure (0/0) + parseJSON j = withNumber "Float" (pure . realToFrac) j + +-- FIXME: lossy conversions + +instance FromJSON Integer where + parseJSON = withNumber "Int" (pure . round) + +instance FromJSON Int where + parseJSON = withNumber "Int" (pure . fromInteger . round) + +instance FromJSON Int8 where + parseJSON = withNumber "Int8" (pure . fromInteger . round) + +instance FromJSON Int16 where + parseJSON = withNumber "Int16" (pure . fromInteger . round) + +instance FromJSON Int32 where + parseJSON = withNumber "Int32" (pure . fromInteger . round) + +instance FromJSON Int64 where + parseJSON = withNumber "Int64" (pure . fromInteger . round) + +instance FromJSON Word where + parseJSON = withNumber "Word" (pure . fromInteger . round) + +instance FromJSON Word8 where + parseJSON = withNumber "Word8" (pure . fromInteger . round) + +instance FromJSON Word16 where + parseJSON = withNumber "Word16" (pure . fromInteger . round) + +instance FromJSON Word32 where + parseJSON = withNumber "Word32" (pure . fromInteger . round) + +instance FromJSON Word64 where + parseJSON = withNumber "Word64" (pure . fromInteger . round) + + +instance FromJSON () where + parseJSON = withArray "()" $ \lst -> + case lst of + [] -> pure () + _ -> pfail "expected ()" + +instance (FromJSON a, FromJSON b) => FromJSON (a,b) where + parseJSON = withArray "(a,b)" $ \lst -> + case lst of + [a,b] -> liftM2 (,) (parseJSON a) (parseJSON b) + _ -> pfail "expected (a,b)" + +instance (FromJSON a, FromJSON b, FromJSON c) => FromJSON (a,b,c) where + parseJSON = withArray "(a,b,c)" $ \lst -> + case lst of + [a,b,c] -> liftM3 (,,) (parseJSON a) (parseJSON b) (parseJSON c) + _ -> pfail "expected (a,b,c)" + +instance (FromJSON a, FromJSON b, FromJSON c, FromJSON d) => FromJSON (a,b,c,d) where + parseJSON = withArray "(a,b,c,d)" $ \lst -> + case lst of + [a,b,c,d] -> liftM4 (,,,) (parseJSON a) (parseJSON b) (parseJSON c) (parseJSON d) + _ -> pfail "expected (a,b,c,d)" + +instance FromJSON a => FromJSON (Maybe a) where + parseJSON Null = pure Nothing + parseJSON j = Just <$> parseJSON j + +instance FromJSON Ordering where + parseJSON = withText "{'LT','EQ','GT'}" $ \s -> + case s of + "LT" -> pure LT + "EQ" -> pure EQ + "GT" -> pure GT + _ -> pfail "expected {'LT','EQ','GT'}" + +instance FromJSON v => FromJSON (Map.Map Text v) where + parseJSON = withObject "Map Text v" $ mapM parseJSON + +-- "prisms" + +withBool :: String -> (Bool -> Parser a) -> Value -> Parser a +withBool _ f (Bool arr) = f arr +withBool expected _ v = typeMismatch expected v + +withText :: String -> (Text -> Parser a) -> Value -> Parser a +withText _ f (String txt) = f txt +withText expected _ v = typeMismatch expected v + +withArray :: String -> ([Value] -> Parser a) -> Value -> Parser a +withArray _ f (Array lst) = f lst +withArray expected _ v = typeMismatch expected v + +withObject :: String -> (Object -> Parser a) -> Value -> Parser a +withObject _ f (Object obj) = f obj +withObject expected _ v = typeMismatch expected v + +withNumber :: String -> (Double -> Parser a) -> Value -> Parser a +withNumber _ f (Number n) = f n +withNumber expected _ v = typeMismatch expected v + +typeMismatch :: String -> Value -> Parser a +typeMismatch expected _ = pfail ("expected " ++ expected) + +---------------------------------------------------------------------------- + +-- | Decode a single JSON document +decode :: FromJSON a => BS.Lazy.ByteString -> Maybe a +decode = decodeStrict . BS.Lazy.toStrict + +-- | Decode a single JSON document +decodeStrict :: FromJSON a => BS.ByteString -> Maybe a +decodeStrict bs = do + v <- decodeValue bs + unP (parseJSON v) + +-- | Decode multiple concatenated JSON documents +decodeStrictN :: FromJSON a => BS.ByteString -> Maybe [a] +decodeStrictN = go [] . scanLexemes + where + go acc [] = Just $! reverse acc + go acc ls = do + (ls', v) <- parseValue ls + a <- unP (parseJSON v) + go (a:acc) ls' + +---- + +type LexStream = [(Lexeme,BS.ByteString)] + +decodeValue :: BS.ByteString -> Maybe Value +decodeValue bs = case parseValue (scanLexemes bs) of + Just ([], v) -> Just v + _ -> Nothing + +parseValue :: LexStream -> Maybe (LexStream, Value) +parseValue = goValue + where + goValue :: LexStream -> Maybe (LexStream, Value) + goValue ((L_True,_):xs) = Just (xs,Bool True) + goValue ((L_False,_):xs) = Just (xs,Bool False) + goValue ((L_Null,_):xs) = Just (xs,Null) + goValue ((L_Number,bs):xs) = (\n->(xs,Number n)) <$> decodeNumber bs + goValue ((L_StrStart,_):xs) = goString xs + goValue ((L_ArrStart,_):xs) = goArray xs + goValue ((L_ObjStart,_):xs) = goObject xs + goValue _ = Nothing + + goArray :: LexStream -> Maybe (LexStream, Value) + goArray xs0 = (Array <$>) <$> go0 xs0 + where + go0 ((L_ArrEnd,_):xs) = pure (xs, []) + go0 xs = do + (xs', v) <- goValue xs + go1 [v] xs' + + go1 acc ((L_ArrEnd,_):xs) = pure (xs, reverse acc) + go1 acc ((L_Comma, _):xs) = do + (xs', v) <- goValue xs + go1 (v:acc) xs' + go1 _ _ = Nothing + + goObject :: LexStream -> Maybe (LexStream, Value) + goObject xs0 = ((Object . Map.fromList) <$>) <$> go0 xs0 + where + go0 ((L_ObjEnd,_):xs) = pure (xs, []) + go0 xs = do + ((L_Colon,_):xs', String k) <- goValue xs + (xs'',v) <- goValue xs' + go1 [(k,v)] xs'' + + go1 acc ((L_ObjEnd,_):xs) = pure (xs, reverse acc) + go1 acc ((L_Comma, _):xs) = do + ((L_Colon,_):xs', String k) <- goValue xs + (xs'',v) <- goValue xs' + go1 ((k,v):acc) xs'' + go1 _ _ = Nothing + + goString :: LexStream -> Maybe (LexStream, Value) + goString xs0 = ((String . T.pack) <$>) <$> go [] xs0 + where + go _ [] = Nothing + go acc ((lx,chunk):xs) = case lx of + L_StrEnd -> pure (xs, concat (reverse acc)) + + L_StrUnescaped -> do + s <- decodeUnescaped chunk + go (s:acc) xs + + L_StrEscaped -> do + c <- decodeEscaped chunk + go ([c]:acc) xs + + L_StrEscapedHex -> do + c <- decodeEscapedHex chunk + go ([c]:acc) xs + + L_StrEscapedHexSurr -> do + c <- decodeEscapedHexSurr chunk + go ([c]:acc) xs + + _ -> Nothing diff --git a/src/Data/Aeson/Micro/Parser.hs b/src/Data/Aeson/Micro/Parser.hs new file mode 100644 --- /dev/null +++ b/src/Data/Aeson/Micro/Parser.hs @@ -0,0 +1,74 @@ +module Data.Aeson.Micro.Parser where + +import Control.Exception as E +import Control.Monad +import Data.Char +import Data.Word +import qualified GHC.Foreign as GHC +import GHC.IO.Encoding +import System.IO.Unsafe +import Text.Read (readMaybe) + +import qualified Data.ByteString as BS +import qualified Data.ByteString.Char8 as BS.Char8 + +decodeEscapedHex :: BS.ByteString -> Maybe Char +decodeEscapedHex bs = do + [0x5c,0x75,d1,d2,d3,d4] <- pure (BS.unpack bs) + + let cp = (0x10*((0x10*((0x10 * h2n d1) + h2n d2)) + h2n d3)) + h2n d4 + + guard (not (0xd800 <= cp && cp <= 0xdfff)) + + pure (chr cp) + +decodeEscapedHexSurr :: BS.ByteString -> Maybe Char +decodeEscapedHexSurr bs = do + [0x5c,0x75,h1,h2,h3,h4,0x5c,0x75,l1,l2,l3,l4] <- pure (BS.unpack bs) + + let hsurr = (0x10*((0x10*((0x10 * h2n h1) + h2n h2)) + h2n h3)) + h2n h4 + lsurr = (0x10*((0x10*((0x10 * h2n l1) + h2n l2)) + h2n l3)) + h2n l4 + + guard ((0xd800 <= hsurr && hsurr <= 0xdbff) && (0xdc00 <= lsurr && lsurr <= 0xdfff)) + + let cp = 0x10000 + ((hsurr-0xd800)*0x400) + (lsurr-0xdc00) + + pure (chr cp) + +decodeNumber :: BS.ByteString -> Maybe Double +decodeNumber = readMaybe . BS.Char8.unpack + +h2n :: Word8 -> Int +h2n w + | 0x30 <= w && w <= 0x39 = fromIntegral (w-0x30) + | 0x41 <= w && w <= 0x46 = fromIntegral (w-0x37) + | 0x61 <= w && w <= 0x66 = fromIntegral (w-0x57) + | otherwise = undefined + +decodeEscaped :: BS.ByteString -> Maybe Char +decodeEscaped bs = do + [0x5c,c] <- pure (BS.unpack bs) + case c of + 0x22 -> pure '\x22' + 0x5c -> pure '\x5c' + 0x2f -> pure '\x2f' + 0x62 -> pure '\x08' + 0x66 -> pure '\x0c' + 0x6e -> pure '\x0a' + 0x72 -> pure '\x0d' + 0x74 -> pure '\x09' + _ -> Nothing + +decodeUnescaped :: BS.ByteString -> Maybe String +decodeUnescaped = decodeString utf8 + +decodeString :: TextEncoding -> BS.ByteString -> Maybe String +decodeString te bs = unsafePerformIO (decodeStringIO te bs) + +{-# NOINLINE decodeStringIO #-} +decodeStringIO :: TextEncoding -> BS.ByteString -> IO (Maybe String) +decodeStringIO te bs = cvtEx <$> try (BS.useAsCStringLen bs (GHC.peekCStringLen te)) + where + cvtEx :: Either IOException a -> Maybe a + cvtEx = either (const Nothing) Just + diff --git a/src/Data/Aeson/Micro/Scanner.x b/src/Data/Aeson/Micro/Scanner.x new file mode 100644 --- /dev/null +++ b/src/Data/Aeson/Micro/Scanner.x @@ -0,0 +1,99 @@ +-- -*- haskell -*- +{ +module Data.Aeson.Micro.Scanner (Lexeme(..), scanLexemes) where + +import qualified Data.ByteString as B +import Data.Word +} + +%encoding "latin1" + +-- c.f. RFC 7159 + +$ws = [\x20\x09\x0a\x0d] + +-- unescaped = %x20-21 / %x23-5B / %x5D-10FFFF +$escaped = [\x00-\x1f\x22\x5c] +$unescaped = [\x00-\xff] # $escaped + +-- zero / ( digit1-9 *DIGIT ) +@int = "0"|[1-9][0-9]* + +-- decimal-point 1*DIGIT +@frac = "."[0-9]+ + +-- e [ minus / plus ] 1*DIGIT +@exp = [eE][\-\+]?[0-9]+ + +-- [ minus ] int [ frac ] [ exp ] +@num = "-"? @int @frac? @exp? + +:- + +<0> $ws ; +<0> "{" { L_ObjStart } +<0> "}" { L_ObjEnd } +<0> "[" { L_ArrStart } +<0> "]" { L_ArrEnd } +<0> \" { L_StrStart } +<0> \: { L_Colon } +<0> \, { L_Comma } +<0> "true" { L_True } +<0> "false" { L_False } +<0> "null" { L_Null } +<0> @num { L_Number } + + [\x22] { L_StrEnd } + $unescaped+ { L_StrUnescaped } + \\[\x22\x5c\x2f\x62\x66\x6e\x72\x74] { L_StrEscaped } + + \\"u"[0-9a-cA-CefEF][0-9a-fA-F]{3} { L_StrEscapedHex } + \\"u"[dD][0-7][0-9a-fA-F]{2} { L_StrEscapedHex } + \\"u"[dD][89abAB][0-9a-fA-F]{2} \\"u"[dD][c-fC-F][0-9a-fA-F]{2} { L_StrEscapedHexSurr } + +{ +data Lexeme + = L_ArrStart + | L_ArrEnd + | L_Colon + | L_Comma + | L_False + | L_Null + | L_Number + | L_ObjStart + | L_ObjEnd + | L_StrStart + | L_StrEnd + | L_StrEscaped + | L_StrEscapedHex + | L_StrEscapedHexSurr + | L_StrUnescaped + | L_True + | L_LexError + deriving (Eq,Ord,Show) + +type AlexInput = B.ByteString + +alexGetByte :: AlexInput -> Maybe (Word8,AlexInput) +alexGetByte = B.uncons + +-- alexInputPrevChar :: AlexInput -> Char + +-- generated by @alex@ +alexScan :: AlexInput -> Int -> AlexReturn Lexeme + +scanLexemes :: B.ByteString -> [(Lexeme, B.ByteString)] +scanLexemes = go False + where + go inStr bs = case alexScan bs (if inStr then string else 0) of + AlexEOF -> [] + AlexError inp' -> [(L_LexError,inp')] + AlexSkip inp' _len -> go inStr inp' + AlexToken inp' len L_StrUnescaped -- workaround for https://github.com/simonmar/alex/issues/119 + | B.length bs - B.length inp' > len + -> (L_StrUnescaped,B.take (B.length bs - B.length inp') bs) + : go inStr inp' + AlexToken inp' len act + -> (act,B.take len bs) + : go (if inStr then act /= L_StrEnd else act == L_StrStart) inp' +}