Command are now stored in ypipes instead of in socketpairs

Storing commands in OS socket buffers caused whole lot of
problems when free space in the buffer ran out. This patch
stores commands in ypipes instead and uses socketpair just
to signal the other thread, ie. at most one byte is stored
in the socketpair at any single instant.

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

1 files changed, 63 insertions, 0 deletions

diff --git a/src/signaler.hpp b/src/signaler.hpp
new file mode 100644
index 0000000..2ebff41
--- /dev/null
+++ b/src/signaler.hpp
@@ -0,0 +1,63 @@
+/*
+    Copyright (c) 2007-2011 iMatix Corporation
+    Copyright (c) 2007-2011 Other contributors as noted in the AUTHORS file
+
+    This file is part of 0MQ.
+
+    0MQ is free software; you can redistribute it and/or modify it under
+    the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    0MQ is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef __ZMQ_SIGNALER_HPP_INCLUDED__
+#define __ZMQ_SIGNALER_HPP_INCLUDED__
+
+#include "fd.hpp"
+
+namespace zmq
+{
+
+    //  This is a cross-platform equivalent to signal_fd. However, as opposed
+    //  to signal_fd there can be at most one signal in the signaler at any
+    //  given moment. Attempt to send a signal before receiving the previous
+    //  one will result in undefined behaviour.
+
+    class signaler_t
+    {
+    public:
+
+        signaler_t ();
+        ~signaler_t ();
+
+        fd_t get_fd ();
+        void send ();
+        int wait (int timeout_);
+        void recv ();
+        
+    private:
+
+        //  Creates a pair of filedescriptors that will be used
+        //  to pass the signals.
+        static int make_fdpair (fd_t *r_, fd_t *w_);
+
+        //  Write & read end of the socketpair.
+        fd_t w;
+        fd_t r;
+
+        //  Disable copying of signaler_t object.
+        signaler_t (const signaler_t&);
+        const signaler_t &operator = (const signaler_t&);
+    };
+
+}
+
+#endif