- wantReadableHandle "hGetContents" handle $ \ handle_ -> do
- {-
- To avoid introducing an extra layer of buffering here,
- we provide three lazy read methods, based on character,
- line, and block buffering.
- -}
- writeHandle handle (handle_{ haType__ = SemiClosedHandle })
- case (haBufferMode__ handle_) of
- LineBuffering -> unsafeInterleaveIO (lazyReadLine handle (haFO__ handle_))
- BlockBuffering _ -> unsafeInterleaveIO (lazyReadBlock handle (haFO__ handle_))
- NoBuffering -> unsafeInterleaveIO (lazyReadChar handle (haFO__ handle_))
-
+ -- can't use wantReadableHandle here, because we want to side effect
+ -- the handle.
+ withHandle handle $ \ handle_ -> do
+ case haType__ handle_ of
+ ErrorHandle theError -> ioError theError
+ ClosedHandle -> ioe_closedHandle "hGetContents" handle
+ SemiClosedHandle -> ioe_closedHandle "hGetContents" handle
+ AppendHandle -> ioError not_readable_error
+ WriteHandle -> ioError not_readable_error
+ _ -> do
+ {-
+ To avoid introducing an extra layer of buffering here,
+ we provide three lazy read methods, based on character,
+ line, and block buffering.
+ -}
+ let handle_' = handle_{ haType__ = SemiClosedHandle }
+ case (haBufferMode__ handle_) of
+ LineBuffering -> do
+ str <- unsafeInterleaveIO (lazyReadLine handle (haFO__ handle_))
+ return (handle_', str)
+ BlockBuffering _ -> do
+ str <- unsafeInterleaveIO (lazyReadBlock handle (haFO__ handle_))
+ return (handle_', str)
+ NoBuffering -> do
+ str <- unsafeInterleaveIO (lazyReadChar handle (haFO__ handle_))
+ return (handle_', str)
+ where
+ not_readable_error =
+ IOError (Just handle) IllegalOperation "hGetContents"
+ ("handle is not open for reading")