X-Git-Url: http://git.cielonegro.org/gitweb.cgi?a=blobdiff_plain;f=Network%2FHTTP%2FLucu%2FAbortion.hs;h=6d36ea8e89ec1b822b30004fecf466c1669baf7b;hb=f62b6f07bbf1eefcf552163d8f7daa6e0862ed5d;hp=b9e4b116250cedee3692aedb9a082ece6d812420;hpb=34b0ad7f2ffc5e7ca67fa3468d01c5551edc8a8b;p=Lucu.git

diff --git a/Network/HTTP/Lucu/Abortion.hs b/Network/HTTP/Lucu/Abortion.hs
index b9e4b11..6d36ea8 100644
--- a/Network/HTTP/Lucu/Abortion.hs
+++ b/Network/HTTP/Lucu/Abortion.hs
@@ -1,6 +1,11 @@
+{-# OPTIONS_HADDOCK prune #-}
+
+-- |Aborting the computation of 'Network.HTTP.Lucu.Resource.Resource'
+-- in any 'Prelude.IO' monads or arrows.
 module Network.HTTP.Lucu.Abortion
     ( Abortion(..)
     , abort
+    , abortPurely
     , abortSTM
     , abortA
     , abortPage
@@ -12,12 +17,12 @@ import           Control.Arrow.ArrowIO
 import           Control.Concurrent.STM
 import           Control.Exception
 import           Control.Monad.Trans
-import           GHC.Conc (unsafeIOToSTM)
+import qualified Data.ByteString.Char8 as C8
 import           Data.Dynamic
+import           GHC.Conc (unsafeIOToSTM)
 import           Network.HTTP.Lucu.Config
 import           Network.HTTP.Lucu.DefaultPage
 import           Network.HTTP.Lucu.Headers
-import           Network.HTTP.Lucu.HttpVersion
 import           Network.HTTP.Lucu.Request
 import           Network.HTTP.Lucu.Response
 import           System.IO.Unsafe
@@ -28,36 +33,71 @@ import           Text.XML.HXT.DOM.XmlKeywords
 
 
 data Abortion = Abortion {
-      aboStatus  :: StatusCode
-    , aboHeaders :: Headers
-    , aboMessage :: Maybe String
+      aboStatus  :: !StatusCode
+    , aboHeaders :: !Headers
+    , aboMessage :: !(Maybe String)
     } deriving (Show, Typeable)
 
+instance Exception Abortion
 
+-- |Computation of @'abort' status headers msg@ aborts the
+-- 'Network.HTTP.Lucu.Resource.Resource' monad with given status,
+-- additional response headers, and optional message string.
+--
+-- What this really does is to throw a special
+-- 'Control.Exception.Exception'. The exception will be caught by the
+-- Lucu system.
+--
+-- 1. If the 'Network.HTTP.Lucu.Resource.Resource' is in the /Deciding
+--    Header/ or any precedent states, it is possible to use the
+--    @status@ and such like as a HTTP response to be sent to the
+--    client.
+--
+-- 2. Otherwise the HTTP response can't be modified anymore so the
+--    only possible thing the system can do is to dump it to the
+--    stderr. See
+--    'Network.HTTP.Lucu.Config.cnfDumpTooLateAbortionToStderr'.
+--
+-- Note that the status code doesn't have to be an error code so you
+-- can use this action for redirection as well as error reporting e.g.
+--
+-- > abort MovedPermanently
+-- >       [("Location", "http://example.net/")]
+-- >       (Just "It has been moved to example.net")
 abort :: MonadIO m => StatusCode -> [ (String, String) ] -> Maybe String -> m a
 abort status headers msg
-    = let abo = Abortion status headers msg
-          exc = DynException (toDyn abo)
+    = status `seq` headers `seq` msg `seq`
+      let abo = Abortion status (toHeaders $ map pack headers) msg
       in
-        liftIO $ throwIO exc
+        liftIO $ throwIO abo
+    where
+      pack (x, y) = (C8.pack x, C8.pack y)
 
+-- |This is similar to 'abort' but computes it with
+-- 'System.IO.Unsafe.unsafePerformIO'.
+abortPurely :: StatusCode -> [ (String, String) ] -> Maybe String -> a
+abortPurely = ((unsafePerformIO .) .) . abort
 
+-- |Computation of @'abortSTM' status headers msg@ just computes
+-- 'abort' in a 'Control.Monad.STM.STM' monad.
 abortSTM :: StatusCode -> [ (String, String) ] -> Maybe String -> STM a
 abortSTM status headers msg
-    = unsafeIOToSTM $ abort status headers msg
-
+    = status `seq` headers `seq` msg `seq`
+      unsafeIOToSTM $! abort status headers msg
 
+-- | Computation of @'abortA' -< (status, (headers, msg))@ just
+-- computes 'abort' in an 'Control.Arrow.ArrowIO.ArrowIO'.
 abortA :: ArrowIO a => a (StatusCode, ([ (String, String) ], Maybe String)) c
 abortA 
     = arrIO3 abort
 
-
 -- aboMessage が Just なら單に mkDefaultPage に渡すだけで良いので樂だが、
 -- Nothing の場合は getDefaultPage を使ってデフォルトのメッセージを得な
 -- ければならない。
 abortPage :: Config -> Maybe Request -> Response -> Abortion -> String
 abortPage conf reqM res abo
-    = case aboMessage abo of
+    = conf `seq` reqM `seq` res `seq` abo `seq`
+      case aboMessage abo of
         Just msg
             -> let [html] = unsafePerformIO 
                             $ runX ( mkDefaultPage conf (aboStatus abo) (txt msg)
@@ -69,7 +109,6 @@ abortPage conf reqM res abo
         Nothing
             -> let res'  = res { resStatus = aboStatus abo }
                    res'' = foldl (.) id [setHeader name value
-                                             | (name, value) <- aboHeaders abo]
-                           $ res'
+                                             | (name, value) <- fromHeaders $ aboHeaders abo] res'
                in
                  getDefaultPage conf reqM res''