From bbe9c55569ffa1ea660a02d7349afb4ba659072d Mon Sep 17 00:00:00 2001
From: sof <unknown>
Date: Mon, 23 Nov 1998 15:44:25 +0000
Subject: [PATCH] [project @ 1998-11-23 15:44:21 by sof] Extend hConnectTo to
also allow output handles to be connected, i.e.,
h1 <- openFile "foo" WriteMode
h2 <- openFile "bar" WriteMode
hConnectTo h1 h2
will cause h1's buffer to be flushed when h2's buffer overflows
(and it is just about to be flushed.) The implementation is currently
not as lazy as that, it flushes h1's buffer regardless of whether h2's
buffer overflows or not.
This is used to connect 'stderr' and 'stdout', i.e., output on
'stderr' will now cause 'stdout' output to (first) be flushed.
---
ghc/lib/std/IO.lhs | 2 ++
ghc/lib/std/PrelHandle.lhs | 39 +++++++++++++++++++++++++++++++---
ghc/lib/std/cbits/filePutc.lc | 2 +-
ghc/lib/std/cbits/flushFile.lc | 17 +++++++++++++--
ghc/lib/std/cbits/stgio.h | 1 +
ghc/lib/std/cbits/writeFile.lc | 1 +
6 files changed, 56 insertions(+), 6 deletions(-)
diff --git a/ghc/lib/std/IO.lhs b/ghc/lib/std/IO.lhs
index 5c8c9fb0b126..4c40d943d1cd 100644
--- a/ghc/lib/std/IO.lhs
+++ b/ghc/lib/std/IO.lhs
@@ -329,6 +329,7 @@ hPutChar :: Handle -> Char -> IO ()
hPutChar handle c = do
handle_ <- wantWriteableHandle "hPutChar" handle
let fo = haFO__ handle_
+ flushConnectedHandle fo
rc <- mayBlock fo (_ccall_ filePutc fo c) -- ConcHask: UNSAFE, may block.
writeHandle handle handle_
if rc == 0
@@ -345,6 +346,7 @@ hPutStr :: Handle -> String -> IO ()
hPutStr handle str = do
handle_ <- wantWriteableHandle "hPutStr" handle
let fo = haFO__ handle_
+ flushConnectedHandle fo
case haBufferMode__ handle_ of
LineBuffering -> do
buf <- _ccall_ getWriteableBuf fo
diff --git a/ghc/lib/std/PrelHandle.lhs b/ghc/lib/std/PrelHandle.lhs
index 91ae3df5d751..c1ca8b2c2190 100644
--- a/ghc/lib/std/PrelHandle.lhs
+++ b/ghc/lib/std/PrelHandle.lhs
@@ -150,7 +150,12 @@ stderr = unsafePerformIO (do
#ifndef __PARALLEL_HASKELL__
fo <- makeForeignObj fo (``&freeStdFileObject''::Addr)
#endif
- newHandle (Handle__ fo WriteHandle NoBuffering "stderr")
+ hdl <- newHandle (Handle__ fo WriteHandle NoBuffering "stderr")
+ -- when stderr and stdout are both connected to a terminal, ensure
+ -- that anything buffered on stdout is flushed prior to writing on stderr.
+ --
+ hConnectTo stdout hdl
+ return hdl
_ -> do ioError <- constructError "stderr"
newHandle (mkErrorHandle__ ioError)
)
@@ -774,12 +779,20 @@ hConnectTo hW hR = hConnectHdl_ hW hR 0{-connect regardless-}
hConnectHdl_ :: Handle -> Handle -> Int -> IO ()
hConnectHdl_ hW hR is_tty = do
- hW_ <- wantWriteableHandle "hConnectTo" hW
- hR_ <- wantReadableHandle "hConnectTo" hR
+ hW_ <- wantRWHandle "hConnectTo" hW
+ hR_ <- wantRWHandle "hConnectTo" hR
_ccall_ setConnectedTo (haFO__ hR_) (haFO__ hW_) is_tty -- ConcHask: SAFE, won't block
writeHandle hR hR_
writeHandle hW hW_
+#ifndef __PARALLEL_HASKELL__
+#define FILE_OBJECT ForeignObj
+#else
+#define FILE_OBJECT Addr
+#endif
+
+flushConnectedHandle :: FILE_OBJECT -> IO ()
+flushConnectedHandle fo = _ccall_ flushConnectedHandle fo
\end{code}
As an extension, we also allow characters to be pushed back.
@@ -985,6 +998,26 @@ wantWriteableHandle fun handle = do
IOError (Just handle) IllegalOperation fun
("handle is not open for writing")
+-- either R or W.
+wantRWHandle :: String -> Handle -> IO Handle__
+wantRWHandle fun handle = do
+ handle_ <- readHandle handle
+ case haType__ handle_ of
+ ErrorHandle ioError -> do
+ writeHandle handle handle_
+ fail ioError
+ ClosedHandle -> do
+ writeHandle handle handle_
+ ioe_closedHandle fun handle
+ SemiClosedHandle -> do
+ writeHandle handle handle_
+ ioe_closedHandle fun handle
+ other -> return handle_
+ where
+ not_readable_error =
+ IOError (Just handle) IllegalOperation fun
+ ("handle is not open for reading or writing")
+
wantSeekableHandle :: String -> Handle -> IO Handle__
wantSeekableHandle fun handle = do
handle_ <- readHandle handle
diff --git a/ghc/lib/std/cbits/filePutc.lc b/ghc/lib/std/cbits/filePutc.lc
index a6ebf3d15593..cf9ffe121398 100644
--- a/ghc/lib/std/cbits/filePutc.lc
+++ b/ghc/lib/std/cbits/filePutc.lc
@@ -49,7 +49,7 @@ StgChar c;
fo->flags = (fo->flags & ~FILEOBJ_RW_READ) | FILEOBJ_RW_WRITE;
- /* check whether we can just add it to the buffer.. */
+ /* check whether we can just add it to the buffer.. */
if ( FILEOBJ_UNBUFFERED(fo) ) {
;
} else {
diff --git a/ghc/lib/std/cbits/flushFile.lc b/ghc/lib/std/cbits/flushFile.lc
index 595dfc01ac6d..6fa7888ff56b 100644
--- a/ghc/lib/std/cbits/flushFile.lc
+++ b/ghc/lib/std/cbits/flushFile.lc
@@ -80,8 +80,21 @@ StgForeignObj ptr;
return 0;
}
-
-\end{code}
+void
+flushConnectedHandle(ptr)
+StgForeignObj ptr;
+{
+ StgInt rc;
+ IOFileObject* fo = (IOFileObject*)ptr;
+ /* if the stream is connected to an output stream, flush it first */
+ if ( fo->connectedTo != NULL && fo->connectedTo->fd != -1 &&
+ (fo->connectedTo->flags & FILEOBJ_WRITE) ) {
+ rc = flushBuffer((StgForeignObj)fo->connectedTo);
+ }
+ /* Willfully ignore return code for now */
+ return;
+}
+\end{code}
diff --git a/ghc/lib/std/cbits/stgio.h b/ghc/lib/std/cbits/stgio.h
index 2bce94b326b3..2769e808cb0a 100644
--- a/ghc/lib/std/cbits/stgio.h
+++ b/ghc/lib/std/cbits/stgio.h
@@ -90,6 +90,7 @@ StgInt fileSize PROTO((StgForeignObj, StgByteArray));
StgInt flushFile PROTO((StgForeignObj));
StgInt flushBuffer PROTO((StgForeignObj));
StgInt flushReadBuffer PROTO((StgForeignObj));
+void flushConnectedHandle PROTO((StgForeignObj));
/* freeFile.lc */
void freeStdFile PROTO((StgForeignObj));
diff --git a/ghc/lib/std/cbits/writeFile.lc b/ghc/lib/std/cbits/writeFile.lc
index ca7bac63d44d..1cd336e71d27 100644
--- a/ghc/lib/std/cbits/writeFile.lc
+++ b/ghc/lib/std/cbits/writeFile.lc
@@ -76,6 +76,7 @@ StgInt len;
if (len == 0 )
return 0;
+
/* First of all, check if we do need to flush the buffer .. */
/* Note - in the case of line buffering, we do not currently check
whether we need to flush buffer due to line terminators in the
--
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