New module 'pipe-filter-ii'.

1 files changed, 116 insertions, 0 deletions

diff --git a/lib/pipe-filter-aux.h b/lib/pipe-filter-aux.h
new file mode 100644
index 0000000000..49644312d2
--- /dev/null
+++ b/lib/pipe-filter-aux.h
@@ -0,0 +1,116 @@
+/* Auxiliary code for filtering of data through a subprocess.
+   Copyright (C) 2001-2003, 2008-2009 Free Software Foundation, Inc.
+   Written by Bruno Haible <haible@clisp.cons.org>, 2009.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+
+#ifndef SSIZE_MAX
+# define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
+#endif
+
+/* We use a child process, and communicate through a bidirectional pipe.
+   To avoid deadlocks, let the child process decide when it wants to read
+   or to write, and let the parent behave accordingly.  The parent uses
+   select() to know whether it must write or read.  On platforms without
+   select(), we use non-blocking I/O.  (This means the parent is busy
+   looping while waiting for the child.  Not good.  But hardly any platform
+   lacks select() nowadays.)  */
+
+/* On BeOS select() works only on sockets, not on normal file descriptors.  */
+#ifdef __BEOS__
+# undef HAVE_SELECT
+#endif
+
+#ifdef EINTR
+
+/* EINTR handling for close(), read(), write(), select().
+   These functions can return -1/EINTR even though we don't have any
+   signal handlers set up, namely when we get interrupted via SIGSTOP.  */
+
+static inline int
+nonintr_close (int fd)
+{
+  int retval;
+
+  do
+    retval = close (fd);
+  while (retval < 0 && errno == EINTR);
+
+  return retval;
+}
+#undef close /* avoid warning related to gnulib module unistd */
+#define close nonintr_close
+
+static inline ssize_t
+nonintr_read (int fd, void *buf, size_t count)
+{
+  ssize_t retval;
+
+  do
+    retval = read (fd, buf, count);
+  while (retval < 0 && errno == EINTR);
+
+  return retval;
+}
+#define read nonintr_read
+
+static inline ssize_t
+nonintr_write (int fd, const void *buf, size_t count)
+{
+  ssize_t retval;
+
+  do
+    retval = write (fd, buf, count);
+  while (retval < 0 && errno == EINTR);
+
+  return retval;
+}
+#undef write /* avoid warning on VMS */
+#define write nonintr_write
+
+# if HAVE_SELECT
+
+static inline int
+nonintr_select (int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
+		struct timeval *timeout)
+{
+  int retval;
+
+  do
+    retval = select (n, readfds, writefds, exceptfds, timeout);
+  while (retval < 0 && errno == EINTR);
+
+  return retval;
+}
+#  undef select /* avoid warning on VMS */
+#  define select nonintr_select
+
+# endif
+
+#endif
+
+/* Non-blocking I/O.  */
+#ifndef O_NONBLOCK
+# define O_NONBLOCK O_NDELAY
+#endif
+#if HAVE_SELECT
+# define IS_EAGAIN(errcode) 0
+#else
+# ifdef EWOULDBLOCK
+#  define IS_EAGAIN(errcode) ((errcode) == EAGAIN || (errcode) == EWOULDBLOCK)
+# else
+#  define IS_EAGAIN(errcode) ((errcode) == EAGAIN)
+# endif
+#endif