[MEDIUM] introduce pipe pools
A new data type has been added : pipes. Some pre-allocated empty pipes
are maintained in a pool for users such as splice which use them a lot
for very short times.
Pipes are allocated using get_pipe() and released using put_pipe().
Pipes which are released with pending data are immediately killed.
The struct pipe is small (16 to 20 bytes) and may even be further
reduced by unifying ->data and ->next.
It would be nice to have a dedicated cleanup task which would watch
for the pipes usage and destroy a few of them from time to time.
diff --git a/include/proto/pipe.h b/include/proto/pipe.h
new file mode 100644
index 0000000..0c02165
--- /dev/null
+++ b/include/proto/pipe.h
@@ -0,0 +1,54 @@
+/*
+ include/proto/pipe.h
+ Pipe management
+
+ Copyright (C) 2000-2009 Willy Tarreau - w@1wt.eu
+
+ This library 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, version 2.1
+ exclusively.
+
+ This library 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 library; if not, write to the Free Software
+ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+*/
+
+#ifndef _PROTO_PIPE_H
+#define _PROTO_PIPE_H
+
+#include <common/config.h>
+#include <types/pipe.h>
+
+extern int pipes_used; /* # of pipes in use (2 fds each) */
+extern int pipes_free; /* # of pipes unused (2 fds each) */
+
+/* return a pre-allocated empty pipe. Try to allocate one if there isn't any
+ * left. NULL is returned if a pipe could not be allocated.
+ */
+struct pipe *get_pipe();
+
+/* destroy a pipe, possibly because an error was encountered on it. Its FDs
+ * will be closed and it will not be reinjected into the live pool.
+ */
+void kill_pipe(struct pipe *p);
+
+/* put back a unused pipe into the live pool. If it still has data in it, it is
+ * closed and not reinjected into the live pool. The caller is not allowed to
+ * use it once released.
+ */
+void put_pipe(struct pipe *p);
+
+#endif /* _PROTO_PIPE_H */
+
+/*
+ * Local variables:
+ * c-indent-level: 8
+ * c-basic-offset: 8
+ * End:
+ */