[newlib-cygwin] Cygwin: fhandler_fifo::hit_eof: improve reliability
Ken Brown
kbrown@sourceware.org
Thu Jul 16 20:00:20 GMT 2020
https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=e10425e1e31ee4db2ae50a67dfb9fe67e83707fe
commit e10425e1e31ee4db2ae50a67dfb9fe67e83707fe
Author: Ken Brown <kbrown@cornell.edu>
Date: Sat Jul 11 14:23:11 2020 -0400
Cygwin: fhandler_fifo::hit_eof: improve reliability
Use the writer count introduced in the previous commit to help detect
EOF. Drop the maybe_eof method, which is no longer needed.
Diff:
---
winsup/cygwin/fhandler.h | 7 +++----
winsup/cygwin/fhandler_fifo.cc | 26 ++------------------------
winsup/cygwin/select.cc | 3 +--
3 files changed, 6 insertions(+), 30 deletions(-)
diff --git a/winsup/cygwin/fhandler.h b/winsup/cygwin/fhandler.h
index f034a110e..b5bfdd0b3 100644
--- a/winsup/cygwin/fhandler.h
+++ b/winsup/cygwin/fhandler.h
@@ -1392,7 +1392,6 @@ class fhandler_fifo: public fhandler_base
UNICODE_STRING pipe_name;
WCHAR pipe_name_buf[CYGWIN_FIFO_PIPE_NAME_LEN + 1];
- bool _maybe_eof;
fifo_client_handler *fc_handler; /* Dynamically growing array. */
int shandlers; /* Size (capacity) of the array. */
int nhandlers; /* Number of elements in the array. */
@@ -1473,9 +1472,9 @@ class fhandler_fifo: public fhandler_base
public:
fhandler_fifo ();
- bool hit_eof ();
- bool maybe_eof () const { return _maybe_eof; }
- void maybe_eof (bool val) { _maybe_eof = val; }
+ /* Called if we appear to be at EOF after polling fc_handlers. */
+ bool hit_eof () const
+ { return !nwriters () && !IsEventSignalled (writer_opening); }
int get_nhandlers () const { return nhandlers; }
fifo_client_handler &get_fc_handler (int i) { return fc_handler[i]; }
PUNICODE_STRING get_pipe_name ();
diff --git a/winsup/cygwin/fhandler_fifo.cc b/winsup/cygwin/fhandler_fifo.cc
index 26b24d019..3685cc0c2 100644
--- a/winsup/cygwin/fhandler_fifo.cc
+++ b/winsup/cygwin/fhandler_fifo.cc
@@ -87,7 +87,7 @@ fhandler_fifo::fhandler_fifo ():
fhandler_base (),
read_ready (NULL), write_ready (NULL), writer_opening (NULL),
owner_needed_evt (NULL), owner_found_evt (NULL), update_needed_evt (NULL),
- cancel_evt (NULL), thr_sync_evt (NULL), _maybe_eof (false),
+ cancel_evt (NULL), thr_sync_evt (NULL),
fc_handler (NULL), shandlers (0), nhandlers (0),
reader (false), writer (false), duplexer (false),
max_atomic_write (DEFAULT_PIPEBUFSIZE),
@@ -361,8 +361,6 @@ fhandler_fifo::record_connection (fifo_client_handler& fc,
fifo_client_connect_state s)
{
fc.state = s;
- maybe_eof (false);
- ResetEvent (writer_opening);
set_pipe_non_blocking (fc.h, true);
}
@@ -1173,25 +1171,6 @@ fhandler_fifo::raw_write (const void *ptr, size_t len)
return ret;
}
-/* A reader is at EOF if the pipe is empty and no writers are open.
- hit_eof is called by raw_read and select.cc:peek_fifo if it appears
- that we are at EOF after polling the fc_handlers. We recheck this
- in case a writer opened while we were polling. */
-bool
-fhandler_fifo::hit_eof ()
-{
- bool ret = maybe_eof () && !IsEventSignalled (writer_opening);
- if (ret)
- {
- yield ();
- /* Wait for the reader thread to finish recording any connection. */
- fifo_client_lock ();
- fifo_client_unlock ();
- ret = maybe_eof ();
- }
- return ret;
-}
-
/* Called from raw_read and select.cc:peek_fifo. */
void
fhandler_fifo::take_ownership ()
@@ -1261,9 +1240,8 @@ fhandler_fifo::raw_read (void *in_ptr, size_t& len)
break;
}
}
- maybe_eof (!nconnected && !IsEventSignalled (writer_opening));
fifo_client_unlock ();
- if (maybe_eof () && hit_eof ())
+ if (!nconnected && hit_eof ())
{
reading_unlock ();
len = 0;
diff --git a/winsup/cygwin/select.cc b/winsup/cygwin/select.cc
index 9ae567c38..80d16f2a7 100644
--- a/winsup/cygwin/select.cc
+++ b/winsup/cygwin/select.cc
@@ -883,9 +883,8 @@ peek_fifo (select_record *s, bool from_select)
goto out;
}
}
- fh->maybe_eof (!nconnected);
fh->fifo_client_unlock ();
- if (fh->maybe_eof () && fh->hit_eof ())
+ if (!nconnected && fh->hit_eof ())
{
select_printf ("read: %s, saw EOF", fh->get_name ());
gotone += s->read_ready = true;
More information about the Cygwin-cvs
mailing list