Clarify -c descriptions.

[rawdog/.git] / rawdoglib / persister.py

diff --git a/rawdoglib/persister.py b/rawdoglib/persister.py
index edc9ee952ebff8ad2f517447c1faeba36df0ff2c..1b8d630953f1c69e147ae86c727efaeb77974604 100644 (file)
--- a/rawdoglib/persister.py
+++ b/rawdoglib/persister.py
@@ -16,7 +16,7 @@
 # write to the Free Software Foundation, Inc., 59 Temple Place, Suite
 # 330, Boston, MA 02111-1307 USA, or see http://www.gnu.org/.
 
-import fcntl
+import fcntl, os
 import cPickle as pickle
 
 class Persistable:
@@ -55,13 +55,15 @@ class Persister:
        def save(self):
                """Save the persisted object back to the file if necessary."""
                if self.object.is_modified():
-                       self.file.seek(0)
-                       self.file.truncate(0)
+                       newname = "%s.new-%d" % (self.filename, os.getpid())
+                       newfile = open(newname, "w")
                        try:
-                               pickle.dump(self.object, self.file, pickle.HIGHEST_PROTOCOL)
+                               pickle.dump(self.object, newfile, pickle.HIGHEST_PROTOCOL)
                        except AttributeError:
                                # Python 2.2 doesn't have the protocol
                                # argument.
-                               pickle.dump(self.object, self.file, True)
+                               pickle.dump(self.object, newfile, True)
+                       newfile.close()
+                       os.rename(newname, self.filename)
                self.file.close()