X-Git-Url: http://git.cielonegro.org/gitweb.cgi?a=blobdiff_plain;f=Network%2FHTTP%2FLucu%2FETag.hs;h=d4a157fa2eabeb66d133afe1b25c3393a59f2946;hb=9668dc27a02b59d7bfb1e9e40af3d2619700ad69;hp=acc496fa2113ef6a0848e570dffd56c453566f4b;hpb=b923d454928e3d01134b15d6072b6d3edf7a15ca;p=Lucu.git

diff --git a/Network/HTTP/Lucu/ETag.hs b/Network/HTTP/Lucu/ETag.hs
index acc496f..d4a157f 100644
--- a/Network/HTTP/Lucu/ETag.hs
+++ b/Network/HTTP/Lucu/ETag.hs
@@ -2,12 +2,10 @@
     OverloadedStrings
   , UnicodeSyntax
   #-}
-{-# OPTIONS_HADDOCK prune #-}
-
--- |Manipulation of entity tags.
+-- |Entity tags
 module Network.HTTP.Lucu.ETag
     ( ETag(..)
-
+    , parseETag
     , printETag
 
     , strongETag
@@ -16,53 +14,76 @@ module Network.HTTP.Lucu.ETag
     , eTagListP
     )
     where
+import Control.Applicative
 import Control.Monad
-import Control.Monad.Unicode
-import Data.Ascii (Ascii)
+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
 
--- |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\".
+      -- 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  ∷ !Ascii
     } deriving (Eq, Show)
 
--- |Convert an 'ETag' to 'Ascii'.
-printETag ∷ ETag → Ascii
+-- |Convert an 'ETag' to an 'AsciiBuilder'.
+printETag ∷ ETag → AsciiBuilder
+{-# INLINEABLE printETag #-}
 printETag et
-    = A.fromAsciiBuilder $
-      ( ( if etagIsWeak et then
-              A.toAsciiBuilder "W/"
-          else
-              (∅)
-        )
-        ⊕
-        quoteStr (etagToken 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' 'Prelude.False'@. If you want to
--- generate an ETag from a file, try using
+-- |This is equivalent to @'ETag' 'False'@. If you want to generate an
+-- ETag from a file, try using
 -- 'Network.HTTP.Lucu.StaticFile.generateETagFromFile'.
 strongETag ∷ Ascii → ETag
+{-# INLINE strongETag #-}
 strongETag = ETag False
 
--- |This is equivalent to @'ETag' 'Prelude.True'@.
+-- |This is equivalent to @'ETag' 'True'@.
 weakETag ∷ Ascii → ETag
+{-# INLINE weakETag #-}
 weakETag = ETag True
 
+-- |'Parser' for an 'ETag'.
 eTagP ∷ Parser ETag
-eTagP = do isWeak ← option False (string "W/" ≫ return True)
+{-# INLINEABLE eTagP #-}
+eTagP = do isWeak ← option False (string "W/" *> return True)
            str    ← quotedStr
            return $ ETag isWeak str
 
+-- |'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"