-{-# OPTIONS_HADDOCK prune #-}
-
--- |Manipulation of entity tags.
+{-# LANGUAGE
+ OverloadedStrings
+ , UnicodeSyntax
+ #-}
+-- |Entity tags
module Network.HTTP.Lucu.ETag
( ETag(..)
+ , parseETag
+ , printETag
+
, strongETag
, weakETag
, eTagP
, eTagListP
)
where
+import Control.Applicative
+import Control.Monad
+import Data.Ascii (Ascii, AsciiBuilder)
+import qualified Data.Ascii as A
+import Data.Attoparsec.Char8
+import Data.Monoid.Unicode
+import Network.HTTP.Lucu.Parser.Http hiding (token)
+import Network.HTTP.Lucu.Utils
+import Prelude.Unicode
-import Control.Monad
-import Network.HTTP.Lucu.Parser
-import Network.HTTP.Lucu.Parser.Http hiding (token)
-import Network.HTTP.Lucu.Utils
-
--- |An entity tag is made of a weakness flag and a opaque string.
+-- |An entity tag consists of a weakness flag and an opaque string.
data ETag = ETag {
-- |The weakness flag. Weak tags looks like W\/\"blahblah\" and
- -- strong tags are like \"blahblah\".
- etagIsWeak :: !Bool
+ -- strong tags are like \"blahblah\". See:
+ -- <http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html#sec13.3.3>
+ etagIsWeak ∷ !Bool
-- |An opaque string. Only characters from 0x20 (sp) to 0x7e (~)
-- are allowed.
- , etagToken :: !String
- } deriving (Eq)
-
-instance Show ETag where
- show (ETag isWeak token) = (if isWeak then
- "W/"
- else
- "")
- ++
- quoteStr token
-
--- |This is equivalent to @'ETag' 'Prelude.False'@. If you want to
--- generate an ETag from a file, try using
+ , etagToken ∷ !Ascii
+ } deriving (Eq, Show)
+
+-- |Convert an 'ETag' to an 'AsciiBuilder'.
+printETag ∷ ETag → AsciiBuilder
+{-# INLINEABLE printETag #-}
+printETag et
+ = ( if etagIsWeak et then
+ A.toAsciiBuilder "W/"
+ else
+ (∅)
+ )
+ ⊕
+ quoteStr (etagToken et)
+
+-- |Parse 'Etag' from an 'Ascii'. This functions throws an exception
+-- for parse error.
+parseETag ∷ Ascii → ETag
+{-# INLINEABLE parseETag #-}
+parseETag str
+ = case parseOnly p $ A.toByteString str of
+ Right et → et
+ Left err → error ("unparsable ETag: " ⧺ A.toString str ⧺ ": " ⧺ err)
+ where
+ p ∷ Parser ETag
+ {-# INLINE p #-}
+ p = do et ← eTagP
+ endOfInput
+ return et
+
+-- |This is equivalent to @'ETag' 'False'@. If you want to generate an
+-- ETag from a file, try using
-- 'Network.HTTP.Lucu.StaticFile.generateETagFromFile'.
-strongETag :: String -> ETag
+strongETag ∷ Ascii → ETag
+{-# INLINE strongETag #-}
strongETag = ETag False
--- |This is equivalent to @'ETag' 'Prelude.True'@.
-weakETag :: String -> ETag
+-- |This is equivalent to @'ETag' 'True'@.
+weakETag ∷ Ascii → ETag
+{-# INLINE weakETag #-}
weakETag = ETag True
-
-eTagP :: Parser ETag
-eTagP = do isWeak <- option False (string "W/" >> return True)
- str <- quotedStr
+-- |'Parser' for an 'ETag'.
+eTagP ∷ Parser ETag
+{-# INLINEABLE eTagP #-}
+eTagP = do isWeak ← option False (string "W/" *> return True)
+ str ← quotedStr
return $ ETag isWeak str
-
-eTagListP :: Parser [ETag]
-eTagListP = allowEOF
- $! do xs <- listOf eTagP
- when (null xs)
- $ fail ""
- return xs
+-- |'Parser' for a list of 'ETag's.
+eTagListP ∷ Parser [ETag]
+{-# INLINEABLE eTagListP #-}
+eTagListP = do xs ← listOf eTagP
+ when (null xs) $
+ fail "empty list of ETags"
+ return xs