X-Git-Url: http://git.cielonegro.org/gitweb.cgi?a=blobdiff_plain;f=Network%2FHTTP%2FLucu%2FAbortion.hs;h=9ff629df73e84db0eac2a50073e06b2494eb120b;hb=0dc3d31312a12f2b085242841b29eb0d96e9c4ac;hp=b9e4b116250cedee3692aedb9a082ece6d812420;hpb=34b0ad7f2ffc5e7ca67fa3468d01c5551edc8a8b;p=Lucu.git

diff --git a/Network/HTTP/Lucu/Abortion.hs b/Network/HTTP/Lucu/Abortion.hs
index b9e4b11..9ff629d 100644
--- a/Network/HTTP/Lucu/Abortion.hs
+++ b/Network/HTTP/Lucu/Abortion.hs
@@ -1,3 +1,7 @@
+-- #prune
+
+-- |Aborting the computation of 'Network.HTTP.Lucu.Resource.Resource'
+-- in any 'Prelude.IO' monads or arrows.
 module Network.HTTP.Lucu.Abortion
     ( Abortion(..)
     , abort
@@ -17,7 +21,6 @@ import           Data.Dynamic
 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 +31,63 @@ 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)
 
-
+-- |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 just throw a special
+-- 'Control.Exception.DynException'. The exception will be caught by
+-- the Lucu.
+--
+-- 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
+    = status `seq` headers `seq` msg `seq`
+      let abo = Abortion status headers msg
           exc = DynException (toDyn abo)
       in
         liftIO $ throwIO exc
 
-
+-- |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)