X-Git-Url: http://git.cielonegro.org/gitweb.cgi?a=blobdiff_plain;f=Network%2FHTTP%2FLucu%2FETag.hs;h=d4a157fa2eabeb66d133afe1b25c3393a59f2946;hb=9668dc27a02b59d7bfb1e9e40af3d2619700ad69;hp=158144cc5254677e59c5080d2636a80c7c6a3b2c;hpb=3d017dd65ddede9a11c5b7a34a91e04340e67bc4;p=Lucu.git

diff --git a/Network/HTTP/Lucu/ETag.hs b/Network/HTTP/Lucu/ETag.hs
index 158144c..d4a157f 100644
--- a/Network/HTTP/Lucu/ETag.hs
+++ b/Network/HTTP/Lucu/ETag.hs
@@ -1,58 +1,90 @@
--- #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