#1607951: Make mailbox.Maildir re-read the directories less frequently.

This is done by recording the current time -1sec, and not re-reading unless
the directory mod. times are >= the recorded time.
This commit is contained in:
Andrew M. Kuchling 2009-05-02 19:17:28 +00:00
parent 6e7bdde2c8
commit 420d4eb1f3
2 changed files with 55 additions and 4 deletions

View File

@ -237,6 +237,7 @@ class Maildir(Mailbox):
else: else:
raise NoSuchMailboxError(self._path) raise NoSuchMailboxError(self._path)
self._toc = {} self._toc = {}
self._last_read = None # Records last time we read cur/new
def add(self, message): def add(self, message):
"""Add message and return assigned key.""" """Add message and return assigned key."""
@ -461,16 +462,35 @@ class Maildir(Mailbox):
def _refresh(self): def _refresh(self):
"""Update table of contents mapping.""" """Update table of contents mapping."""
new_mtime = os.path.getmtime(os.path.join(self._path, 'new'))
cur_mtime = os.path.getmtime(os.path.join(self._path, 'cur'))
if (self._last_read is not None and
new_mtime <= self._last_read and cur_mtime <= self._last_read):
return
self._toc = {} self._toc = {}
for subdir in ('new', 'cur'): def update_dir (subdir):
subdir_path = os.path.join(self._path, subdir) path = os.path.join(self._path, subdir)
for entry in os.listdir(subdir_path): for entry in os.listdir(path):
p = os.path.join(subdir_path, entry) p = os.path.join(path, entry)
if os.path.isdir(p): if os.path.isdir(p):
continue continue
uniq = entry.split(self.colon)[0] uniq = entry.split(self.colon)[0]
self._toc[uniq] = os.path.join(subdir, entry) self._toc[uniq] = os.path.join(subdir, entry)
update_dir('new')
update_dir('cur')
# We record the current time - 1sec so that, if _refresh() is called
# again in the same second, we will always re-read the mailbox
# just in case it's been modified. (os.path.mtime() only has
# 1sec resolution.) This results in a few unnecessary re-reads
# when _refresh() is called multiple times in the same second,
# but once the clock ticks over, we will only re-read as needed.
now = int(time.time() - 1)
self._last_read = time.time() - 1
def _lookup(self, key): def _lookup(self, key):
"""Use TOC to return subpath for given key, or raise a KeyError.""" """Use TOC to return subpath for given key, or raise a KeyError."""
try: try:

View File

@ -747,6 +747,37 @@ class TestMaildir(TestMailbox):
perms = st.st_mode perms = st.st_mode
self.assertFalse((perms & 0111)) # Execute bits should all be off. self.assertFalse((perms & 0111)) # Execute bits should all be off.
def test_reread(self):
# Wait for 2 seconds
time.sleep(2)
# Initially, the mailbox has not been read and the time is null.
assert getattr(self._box, '_last_read', None) is None
# Refresh mailbox; the times should now be set to something.
self._box._refresh()
assert getattr(self._box, '_last_read', None) is not None
# Try calling _refresh() again; the modification times shouldn't have
# changed, so the mailbox should not be re-reading. Re-reading causes
# the ._toc attribute to be assigned a new dictionary object, so
# we'll check that the ._toc attribute isn't a different object.
orig_toc = self._box._toc
def refreshed():
return self._box._toc is not orig_toc
time.sleep(1) # Wait 1sec to ensure time.time()'s value changes
self._box._refresh()
assert not refreshed()
# Now, write something into cur and remove it. This changes
# the mtime and should cause a re-read.
filename = os.path.join(self._path, 'cur', 'stray-file')
f = open(filename, 'w')
f.close()
os.unlink(filename)
self._box._refresh()
assert refreshed()
class _TestMboxMMDF(TestMailbox): class _TestMboxMMDF(TestMailbox):