[Python-checkins] cpython (3.2): #9559: Append data to single-file mailbox files if messages are only added
petri.lehtinen
python-checkins at python.org
Thu Jun 28 12:59:04 CEST 2012
http://hg.python.org/cpython/rev/5f447a005d67
changeset: 77833:5f447a005d67
branch: 3.2
parent: 77819:d07319eeae87
user: Petri Lehtinen <petri at digip.org>
date: Thu Jun 28 13:48:17 2012 +0300
summary:
#9559: Append data to single-file mailbox files if messages are only added
If messages were only added, a new file is no longer created and
renamed over the old file when flush() is called on an mbox, MMDF or
Babyl mailbox.
files:
Lib/mailbox.py | 18 ++++++++++++++--
Lib/test/test_mailbox.py | 29 ++++++++++++++++++++++++++-
Misc/NEWS | 4 +++
3 files changed, 46 insertions(+), 5 deletions(-)
diff --git a/Lib/mailbox.py b/Lib/mailbox.py
--- a/Lib/mailbox.py
+++ b/Lib/mailbox.py
@@ -587,16 +587,19 @@
self._file = f
self._toc = None
self._next_key = 0
- self._pending = False # No changes require rewriting the file.
+ self._pending = False # No changes require rewriting the file.
+ self._pending_sync = False # No need to sync the file
self._locked = False
- self._file_length = None # Used to record mailbox size
+ self._file_length = None # Used to record mailbox size
def add(self, message):
"""Add message and return assigned key."""
self._lookup()
self._toc[self._next_key] = self._append_message(message)
self._next_key += 1
- self._pending = True
+ # _append_message appends the message to the mailbox file. We
+ # don't need a full rewrite + rename, sync is enough.
+ self._pending_sync = True
return self._next_key - 1
def remove(self, key):
@@ -642,6 +645,11 @@
def flush(self):
"""Write any pending changes to disk."""
if not self._pending:
+ if self._pending_sync:
+ # Messages have only been added, so syncing the file
+ # is enough.
+ _sync_flush(self._file)
+ self._pending_sync = False
return
# In order to be writing anything out at all, self._toc must
@@ -695,6 +703,7 @@
self._file = open(self._path, 'rb+')
self._toc = new_toc
self._pending = False
+ self._pending_sync = False
if self._locked:
_lock_file(self._file, dotlock=False)
@@ -731,6 +740,9 @@
"""Append message to mailbox and return (start, stop) offsets."""
self._file.seek(0, 2)
before = self._file.tell()
+ if len(self._toc) == 0:
+ # This is the first message
+ self._pre_mailbox_hook(self._file)
try:
self._pre_message_hook(self._file)
offsets = self._install_message(message)
diff --git a/Lib/test/test_mailbox.py b/Lib/test/test_mailbox.py
--- a/Lib/test/test_mailbox.py
+++ b/Lib/test/test_mailbox.py
@@ -942,7 +942,32 @@
self._box._refresh()
self.assertTrue(refreshed())
-class _TestMboxMMDF(TestMailbox):
+
+class _TestSingleFile(TestMailbox):
+ '''Common tests for single-file mailboxes'''
+
+ def test_add_doesnt_rewrite(self):
+ # When only adding messages, flush() should not rewrite the
+ # mailbox file. See issue #9559.
+
+ # Inode number changes if the contents are written to another
+ # file which is then renamed over the original file. So we
+ # must check that the inode number doesn't change.
+ inode_before = os.stat(self._path).st_ino
+
+ self._box.add(self._template % 0)
+ self._box.flush()
+
+ inode_after = os.stat(self._path).st_ino
+ self.assertEqual(inode_before, inode_after)
+
+ # Make sure the message was really added
+ self._box.close()
+ self._box = self._factory(self._path)
+ self.assertEqual(len(self._box), 1)
+
+
+class _TestMboxMMDF(_TestSingleFile):
def tearDown(self):
super().tearDown()
@@ -1217,7 +1242,7 @@
return os.path.join(self._path, '.mh_sequences.lock')
-class TestBabyl(TestMailbox, unittest.TestCase):
+class TestBabyl(_TestSingleFile, unittest.TestCase):
_factory = lambda self, path, factory=None: mailbox.Babyl(path, factory)
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -81,6 +81,10 @@
Library
-------
+- Issue #9559: If messages were only added, a new file is no longer
+ created and renamed over the old file when flush() is called on an
+ mbox, MMDF or Babyl mailbox.
+
- Issue #14653: email.utils.mktime_tz() no longer relies on system
mktime() when timezone offest is supplied.
--
Repository URL: http://hg.python.org/cpython
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