X-Git-Url: http://git.cielonegro.org/gitweb.cgi?a=blobdiff_plain;f=Network%2FHTTP%2FLucu%2FETag.hs;h=d87100095a71e78cafeba5435cdf02c397111b26;hb=b1fac0a;hp=0341f5ac382b245638575477b0474ec0b1fafe40;hpb=1000bdc46cfe7b3ae550ff24ccea9f440f11b42a;p=Lucu.git

diff --git a/Network/HTTP/Lucu/ETag.hs b/Network/HTTP/Lucu/ETag.hs
index 0341f5a..d871000 100644
--- a/Network/HTTP/Lucu/ETag.hs
+++ b/Network/HTTP/Lucu/ETag.hs
@@ -1,46 +1,85 @@
+{-# LANGUAGE
+    OverloadedStrings
+  , UnicodeSyntax
+  #-}
+-- |Entity tags
 module Network.HTTP.Lucu.ETag
-    ( ETag
-    , mkETag    -- Bool -> String -> ETag
-    , eTagP     -- Parser ETag
-    , eTagListP -- Parser [ETag]
+    ( ETag(..)
+    , parseETag
+    , printETag
+
+    , strongETag
+    , weakETag
+    , eTag
+    , eTagList
     )
     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
+import Network.HTTP.Lucu.Parser.Http hiding (token)
+import Network.HTTP.Lucu.Utils
+import Prelude.Unicode
 
-import           Network.HTTP.Lucu.Parser
-import           Network.HTTP.Lucu.Parser.Http
-
-
+-- |An entity tag consists of a weakness flag and an opaque string.
 data ETag = ETag {
-      etagIsWeak :: Bool
-    , etagToken  :: String
-    } deriving (Eq)
-
-
-instance Show ETag where
-    show (ETag isWeak token) = (if isWeak then
-                                    "W/"
-                                else
-                                    "")
-                               ++
-                               foldr (++) "" (["\""] ++ map quote token ++ ["\""])
-        where
-          quote :: Char -> String
-          quote '"' = "\\\""
-          quote c   = [c]
+      -- |The weakness flag. Weak tags looks like W\/\"blahblah\" and
+      -- 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 an 'AsciiBuilder'.
+printETag ∷ ETag → AsciiBuilder
+{-# INLINEABLE printETag #-}
+printETag et
+    = ( if etagIsWeak et then
+            A.toAsciiBuilder "W/"
+        else
+            (∅)
+      )
+      ⊕
+      quoteStr (etagToken et)
 
-mkETag :: Bool -> String -> ETag
-mkETag = ETag
+-- |Parse 'Etag' from an 'Ascii'. This functions throws an exception
+-- for parse error.
+parseETag ∷ Ascii → ETag
+{-# INLINEABLE parseETag #-}
+parseETag str
+    = case parseOnly (finishOff eTag) $ A.toByteString str of
+        Right et → et
+        Left err → error ("unparsable ETag: " ⧺ A.toString str ⧺ ": " ⧺ err)
 
+-- |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
 
-eTagP :: Parser ETag
-eTagP = do isWeak <- option False (string "W/" >> return True)
-           str    <- quotedStr
-           return $ mkETag isWeak str
+-- |This is equivalent to @'ETag' 'True'@.
+weakETag ∷ Ascii → ETag
+{-# INLINE weakETag #-}
+weakETag = ETag True
 
+-- |'Parser' for an 'ETag'.
+eTag ∷ Parser ETag
+{-# INLINEABLE eTag #-}
+eTag = do isWeak ← option False (string "W/" *> return True)
+          str    ← quotedStr
+          return $ ETag isWeak str
 
-eTagListP :: Parser [ETag]
-eTagListP = allowEOF
-            $ sepBy1 eTagP (do many sp
-                               char ','
-                               many sp)
+-- |'Parser' for a list of 'ETag's.
+eTagList ∷ Parser [ETag]
+{-# INLINEABLE eTagList #-}
+eTagList = do xs ← listOf eTag
+              when (null xs) $
+                  fail "empty list of ETags"
+              return xs