[Python-checkins] r52692 - in python/trunk: Lib/mailbox.py Misc/NEWS

Thu Nov 9 14:51:15 CET 2006

Author: andrew.kuchling
Date: Thu Nov 9 14:51:14 2006
New Revision: 52692
Modified:
 python/trunk/Lib/mailbox.py
 python/trunk/Misc/NEWS
Log:
[Patch #1514544 by David Watson] use fsync() to ensure data is really on disk
Modified: python/trunk/Lib/mailbox.py
==============================================================================

--- python/trunk/Lib/mailbox.py	(original)
+++ python/trunk/Lib/mailbox.py	Thu Nov 9 14:51:14 2006
@@ -2,6 +2,12 @@
 
 """Read/write support for Maildir, mbox, MH, Babyl, and MMDF mailboxes."""
 
+# Notes for authors of new mailbox subclasses:
+#
+# Remember to fsync() changes to disk before closing a modified file
+# or returning from a flush() method. See functions _sync_flush() and
+# _sync_close().
+
 import sys
 import os
 import time
@@ -238,7 +244,7 @@
 try:
 self._dump_message(message, tmp_file)
 finally:
- tmp_file.close()
+ _sync_close(tmp_file)
 if isinstance(message, MaildirMessage):
 subdir = message.get_subdir()
 suffix = self.colon + message.get_info()
@@ -565,7 +571,8 @@
 new_file.close()
 os.remove(new_file.name)
 raise
- new_file.close()
+ _sync_close(new_file)
+ # self._file is about to get replaced, so no need to sync.
 self._file.close()
 try:
 os.rename(new_file.name, self._path)
@@ -599,7 +606,7 @@
 self.flush()
 if self._locked:
 self.unlock()
- self._file.close()
+ self._file.close() # Sync has been done by self.flush() above.
 
 def _lookup(self, key=None):
 """Return (start, stop) or raise KeyError."""
@@ -789,7 +796,7 @@
 if self._locked:
 _unlock_file(f)
 finally:
- f.close()
+ _sync_close(f)
 return new_key
 
 def remove(self, key):
@@ -836,7 +843,7 @@
 if self._locked:
 _unlock_file(f)
 finally:
- f.close()
+ _sync_close(f)
 
 def get_message(self, key):
 """Return a Message representation or raise a KeyError."""
@@ -923,7 +930,7 @@
 """Unlock the mailbox if it is locked."""
 if self._locked:
 _unlock_file(self._file)
- self._file.close()
+ _sync_close(self._file)
 del self._file
 self._locked = False
 
@@ -1020,7 +1027,7 @@
 else:
 f.write('\n')
 finally:
- f.close()
+ _sync_close(f)
 
 def pack(self):
 """Re-name messages to eliminate numbering gaps. Invalidates keys."""
@@ -1874,6 +1881,15 @@
 socket.gethostname(),
 os.getpid()))
 
+def _sync_flush(f):
+ """Ensure changes to file f are physically on disk."""
+ f.flush()
+ os.fsync(f.fileno())
+
+def _sync_close(f):
+ """Close file f, ensuring all changes are physically on disk."""
+ _sync_flush(f)
+ f.close()
 
 ## Start: classes from the original module (for backward compatibility).
 
Modified: python/trunk/Misc/NEWS
==============================================================================
--- python/trunk/Misc/NEWS	(original)
+++ python/trunk/Misc/NEWS	Thu Nov 9 14:51:14 2006
@@ -100,6 +100,10 @@
 weren't passing the message factory on to newly created Maildir/MH
 objects.
 
+- Patch #1514544: Try to ensure that messages/indexes have been physically
+ written to disk after calling .flush() or .close(). (Patch by David
+ Watson.)
+
 - Patch #1592250: Add elidge argument to Tkinter.Text.search.
 
 - Patch #838546: Make terminal become controlling in pty.fork()
