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-rwxr-xr-xLib/mailbox.py28
-rw-r--r--Lib/test/test_mailbox.py31
2 files changed, 55 insertions, 4 deletions
diff --git a/Lib/mailbox.py b/Lib/mailbox.py
index 909285b..85e3ab1 100755
--- a/Lib/mailbox.py
+++ b/Lib/mailbox.py
@@ -233,6 +233,7 @@ class Maildir(Mailbox):
else:
raise NoSuchMailboxError(self._path)
self._toc = {}
+ self._last_read = None # Records last time we read cur/new
def add(self, message):
"""Add message and return assigned key."""
@@ -457,16 +458,35 @@ class Maildir(Mailbox):
def _refresh(self):
"""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 = {}
- for subdir in ('new', 'cur'):
- subdir_path = os.path.join(self._path, subdir)
- for entry in os.listdir(subdir_path):
- p = os.path.join(subdir_path, entry)
+ def update_dir (subdir):
+ path = os.path.join(self._path, subdir)
+ for entry in os.listdir(path):
+ p = os.path.join(path, entry)
if os.path.isdir(p):
continue
uniq = entry.split(self.colon)[0]
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):
"""Use TOC to return subpath for given key, or raise a KeyError."""
try:
diff --git a/Lib/test/test_mailbox.py b/Lib/test/test_mailbox.py
index 28b9322..655b639 100644
--- a/Lib/test/test_mailbox.py
+++ b/Lib/test/test_mailbox.py
@@ -740,6 +740,37 @@ class TestMaildir(TestMailbox):
perms = st.st_mode
self.assertFalse((perms & 0o111)) # 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):