X-Git-Url: https://git.distorted.org.uk/~mdw/mLib-python/blobdiff_plain/ea2fc600626d9c59df58fd46a369eacea57f02fe..965caf5fc74fbbf2516eb1d098fac07cfbdb6820:/mdup.pyx

diff --git a/mdup.pyx b/mdup.pyx
index 24cd995..12e727c 100644
--- a/mdup.pyx
+++ b/mdup.pyx
@@ -1,45 +1,54 @@
-# -*-pyrex-*-
-#
-# $Id$
-#
-# File descriptor juggling
-#
-# (c) 2009 Straylight/Edgeware
-#
+### -*-pyrex-*-
+###
+### File descriptor juggling
+###
+### (c) 2009 Straylight/Edgeware
+###
 
-#----- Licensing notice -----------------------------------------------------
-#
-# This file is part of the Python interface to mLib.
-#
-# mLib/Python 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 2 of the License, or
-# (at your option) any later version.
-#
-# mLib/Python 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 mLib/Python; if not, write to the Free Software Foundation,
-# Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+###----- Licensing notice ---------------------------------------------------
+###
+### This file is part of the Python interface to mLib.
+###
+### mLib/Python 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 2 of the License, or
+### (at your option) any later version.
+###
+### mLib/Python 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 mLib/Python; if not, write to the Free Software Foundation,
+### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 
 def mdup(v):
-  cdef mdup_fd *vv
+  """
+  mdup(LIST) -> LIST:
+    LIST is a list (mutable sequence) of pairs (CUR, WANT).  Duplicate each
+    CUR file descriptor as WANT (may be -1 to mean `don't care'), closing
+    original CUR.  Works even if there are cycles.  LIST is updated in place
+    with CUR reflecting the new file descriptors even on error.  Returns the
+    same LIST on success.
+  """
+  cdef mdup_fd *vv = NULL
   cdef size_t n
   cdef int i
   cdef int rc
 
   n = len(v)
   vv = <mdup_fd *>xmalloc(n * PSIZEOF(vv))
-  for 0 <= i < n:
-    vv[i].cur, vv[i].want = v[i]
-  rc = _mdup(vv, n)
-  for 0 <= i < n:
-    v[i] = vv[i].cur, vv[i].want
-  if rc < 0:
-    _oserror()
+  try:
+    for 0 <= i < n:
+      vv[i].cur, vv[i].want = v[i]
+    rc = _mdup(vv, n)
+    for 0 <= i < n:
+      v[i] = vv[i].cur, vv[i].want
+    if rc < 0:
+      _oserror()
+  finally:
+    xfree(vv)
   return v
 
-#----- That's all, folks ----------------------------------------------------
+###----- That's all, folks --------------------------------------------------