+{-# LANGUAGE
+ BangPatterns
+ , OverloadedStrings
+ , UnicodeSyntax
+ #-}
+-- |Utility functions used internally in the Lucu httpd. These
+-- functions may be useful too for something else.
module Network.HTTP.Lucu.Utils
- ( splitBy -- (a -> Bool) -> [a] -> [[a]]
- , joinWith -- [a] -> [[a]] -> [a]
- , trim -- (a -> Bool) -> [a] -> [a]
- , noCaseEq -- String -> String -> Bool
- , isWhiteSpace -- Char -> Bool
+ ( splitBy
+ , joinWith
+ , quoteStr
+ , parseWWWFormURLEncoded
+ , show3
)
where
+import Blaze.ByteString.Builder.ByteString as B
+import Blaze.Text.Int as BT
+import Control.Monad
+import Data.Ascii (Ascii, AsciiBuilder)
+import qualified Data.Ascii as A
+import Data.ByteString (ByteString)
+import qualified Data.ByteString.Char8 as BS
+import Data.List hiding (last)
+import Data.Monoid.Unicode
+import Network.URI
+import Prelude hiding (last)
+import Prelude.Unicode
-import Control.Monad.Trans
-import Data.Char
-import Data.List
-import Foreign
-import Foreign.C
-
-
-splitBy :: (a -> Bool) -> [a] -> [[a]]
-splitBy isSeparator src
- = case break isSeparator src
- of (last , [] ) -> last : []
- (first, sep:rest) -> first : splitBy isSeparator rest
-
-
-joinWith :: [a] -> [[a]] -> [a]
-joinWith separator xs
- = foldr (++) [] $ intersperse separator xs
+-- |> splitBy (== ':') "ab:c:def"
+-- > ==> ["ab", "c", "def"]
+splitBy ∷ (a → Bool) → [a] → [[a]]
+splitBy isSep src
+ = case break isSep src
+ of (last , [] ) → [last]
+ (first, _sep:rest) → first : splitBy isSep rest
+-- |> joinWith ":" ["ab", "c", "def"]
+-- > ==> "ab:c:def"
+joinWith ∷ Ascii → [AsciiBuilder] → AsciiBuilder
+{-# INLINEABLE joinWith #-}
+joinWith sep = flip go (∅)
+ where
+ go ∷ [AsciiBuilder] → AsciiBuilder → AsciiBuilder
+ {-# INLINE go #-}
+ go [] ab = ab
+ go (x:[]) ab = ab ⊕ x
+ go (x:xs) ab = go xs (ab ⊕ A.toAsciiBuilder sep ⊕ x)
-trim :: (a -> Bool) -> [a] -> [a]
-trim p = trimTail . trimHead
+-- |> quoteStr "abc"
+-- > ==> "\"abc\""
+--
+-- > quoteStr "ab\"c"
+-- > ==> "\"ab\\\"c\""
+quoteStr ∷ Ascii → AsciiBuilder
+quoteStr str = A.toAsciiBuilder "\"" ⊕
+ go (A.toByteString str) (∅) ⊕
+ A.toAsciiBuilder "\""
where
- trimHead = dropWhile p
- trimTail = reverse . trimHead . reverse
+ go ∷ BS.ByteString → AsciiBuilder → AsciiBuilder
+ go bs ab
+ = case BS.break (≡ '"') bs of
+ (x, y)
+ | BS.null y → ab ⊕ b2ab x
+ | otherwise → go (BS.tail y) (ab ⊕ b2ab x
+ ⊕ A.toAsciiBuilder "\\\"")
+ b2ab ∷ BS.ByteString → AsciiBuilder
+ b2ab = A.toAsciiBuilder ∘ A.unsafeFromByteString
-noCaseEq :: String -> String -> Bool
-noCaseEq a b
- = (map toLower a) == (map toLower b)
+-- |> parseWWWFormURLEncoded "aaa=bbb&ccc=ddd"
+-- > ==> [("aaa", "bbb"), ("ccc", "ddd")]
+parseWWWFormURLEncoded ∷ Ascii → [(ByteString, ByteString)]
+parseWWWFormURLEncoded src
+ -- THINKME: We could gain some performance by using attoparsec
+ -- here.
+ | src ≡ "" = []
+ | otherwise = do pairStr ← splitBy (\ c → c ≡ ';' ∨ c ≡ '&') (A.toString src)
+ let (key, value) = break (≡ '=') pairStr
+ return ( unescape key
+ , unescape $ case value of
+ ('=':val) → val
+ val → val
+ )
+ where
+ unescape ∷ String → ByteString
+ unescape = BS.pack ∘ unEscapeString ∘ map plusToSpace
+ plusToSpace ∷ Char → Char
+ plusToSpace '+' = ' '
+ plusToSpace c = c
-isWhiteSpace :: Char -> Bool
-isWhiteSpace = flip elem " \t\r\n"
+-- |> show3 5
+-- > ==> "005"
+show3 ∷ Integral n ⇒ n → AsciiBuilder
+{-# INLINEABLE show3 #-}
+show3 = A.unsafeFromBuilder ∘ go
+ where
+ go i | i ≥ 0 ∧ i < 10 = B.fromByteString "00" ⊕ BT.digit i
+ | i ≥ 0 ∧ i < 100 = B.fromByteString "0" ⊕ BT.integral i
+ | i ≥ 0 ∧ i < 1000 = BT.integral i
+ | otherwise = error ("show3: the integer i must satisfy 0 <= i < 1000: " ⧺ show i)