Add Gmail IMAP special support.

New repository/folder classes to support "real deletion" of messages
thorugh Gmail's IMAP interface: to really delete a message in Gmail,
one has to move it to the Trash folder, rather than EXPUNGE it.

offlineimap/folder/Gmail.py

@@ -0,0 +1,119 @@
+# Gmail IMAP folder support
+# Copyright (C) 2008 Riccardo Murri <riccardo.murri@gmail.com>
+# Copyright (C) 2002-2007 John Goerzen <jgoerzen@complete.org>
+#
+#    This program is free software; you can redistribute it and/or modify
+#    it under the terms of the GNU General Public License as published by
+#    the Free Software Foundation; either version 2 of the License, or
+#    (at your option) any later version.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU General Public License for more details.
+#
+#    You should have received a copy of the GNU General Public License
+#    along with this program; if not, write to the Free Software
+#    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+
+"""Folder implementation to support features of the Gmail IMAP server.
+"""
+
+from IMAP import IMAPFolder
+import imaplib
+from offlineimap import imaputil, imaplibutil
+from offlineimap.ui import UIBase
+from copy import copy
+
+
+class GmailFolder(IMAPFolder):
+    """Folder implementation to support features of the Gmail IMAP server.
+    Specifically, deleted messages are moved to folder `Gmail.TRASH_FOLDER`
+    (by default: ``[Gmail]/Trash``) prior to expunging them, since
+    Gmail maps to IMAP ``EXPUNGE`` command to "remove label".
+
+    For more information on the Gmail IMAP server:
+      http://mail.google.com/support/bin/answer.py?answer=77657&topic=12815
+    """
+
+    #: Where deleted mail should be moved
+    TRASH_FOLDER='[Gmail]/Trash'
+
+    #: Gmail will really delete messages upon EXPUNGE in these folders
+    REAL_DELETE_FOLDERS = [ TRASH_FOLDER, '[Gmail]/Spam' ]
+
+    def __init__(self, imapserver, name, visiblename, accountname, repository):
+        self.realdelete = repository.getrealdelete(name)
+        IMAPFolder.__init__(self, imapserver, name, visiblename, \
+                            accountname, repository)
+
+    def deletemessages_noconvert(self, uidlist):
+        uidlist = [uid for uid in uidlist if uid in self.messagelist]
+        if not len(uidlist):
+            return        
+
+        if self.realdelete and not (self.getname() in self.REAL_DELETE_FOLDERS):
+            # IMAP expunge is just "remove label" in this folder,
+            # so map the request into a "move into Trash"
+
+            imapobj = self.imapserver.acquireconnection()
+            try:
+                imapobj.select(self.getfullname())
+                result = imapobj.uid('copy',
+                                     imaputil.listjoin(uidlist),
+                                     self.TRASH_FOLDER)
+                assert result[0] == 'OK', \
+                       "Bad IMAPlib result: %s" % result[0]
+            finally:
+                self.imapserver.releaseconnection(imapobj)
+            for uid in uidlist:
+                del self.messagelist[uid]
+        else:
+            IMAPFolder.deletemessages_noconvert(self, uidlist)
+            
+    def processmessagesflags(self, operation, uidlist, flags):
+        # XXX: the imapobj.myrights(...) calls dies with an error
+        # report from Gmail server stating that IMAP command
+        # 'MYRIGHTS' is not implemented.  So, this
+        # `processmessagesflags` is just a copy from `IMAPFolder`,
+        # with the references to `imapobj.myrights()` deleted This
+        # shouldn't hurt, however, Gmail users always have full
+        # control over all their mailboxes (apparently).
+        if len(uidlist) > 101:
+            # Hack for those IMAP ervers with a limited line length
+            self.processmessagesflags(operation, uidlist[:100], flags)
+            self.processmessagesflags(operation, uidlist[100:], flags)
+            return
+        
+        imapobj = self.imapserver.acquireconnection()
+        try:
+            imapobj.select(self.getfullname())
+            r = imapobj.uid('store',
+                            imaputil.listjoin(uidlist),
+                            operation + 'FLAGS',
+                            imaputil.flagsmaildir2imap(flags))
+            assert r[0] == 'OK', 'Error with store: ' + '. '.join(r[1])
+            r = r[1]
+        finally:
+            self.imapserver.releaseconnection(imapobj)
+
+        needupdate = copy(uidlist)
+        for result in r:
+            attributehash = imaputil.flags2hash(imaputil.imapsplit(result)[1])
+            flags = attributehash['FLAGS']
+            uid = long(attributehash['UID'])
+            self.messagelist[uid]['flags'] = imaputil.flagsimap2maildir(flags)
+            try:
+                needupdate.remove(uid)
+            except ValueError:          # Let it slide if it's not in the list
+                pass
+        for uid in needupdate:
+            if operation == '+':
+                for flag in flags:
+                    if not flag in self.messagelist[uid]['flags']:
+                        self.messagelist[uid]['flags'].append(flag)
+                    self.messagelist[uid]['flags'].sort()
+            elif operation == '-':
+                for flag in flags:
+                    if flag in self.messagelist[uid]['flags']:
+                        self.messagelist[uid]['flags'].remove(flag)

offlineimap/folder/__init__.py

@@ -1,2 +1,2 @@
-import Base, IMAP, Maildir, LocalStatus
+import Base, Gmail, IMAP, Maildir, LocalStatus