Allow to create the root MailDir directory

We currently do not allow nametrans rules such as
nametrans = lambda foldername: re.sub('^INBOX$', '', foldername)

because we crash with a traceback when running:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=499755

The underlying reason is that we cannot create the "top level" root
directory of the Maildir in the function makefolders(), it will bail
out. John Goerzen intentionally prevented offlineimap from creating the
top-level dir, so that a misconfiguration could not arbitrarily create
folders on the file system. I believe that it should be perfectly
possible to automatically create the root dirctory of the maildir. We
still protect against folder creations at arbitrary places in the file
system though.

This patch cleans up makefolders(), adds documentation, allows to
automatically create rootfolders if needed (using absolute paths) and
adds some robustness in case the folders already exist that we want to
create (rather than simply crapping out).

Signed-off-by: Sebastian Spaeth <Sebastian@SSpaeth.de>
Signed-off-by: Nicolas Sebrecht <nicolas.s-dev@laposte.net>

offlineimap/repository/Maildir.py

@@ -65,46 +65,46 @@ class MaildirRepository(BaseRepository):
         return self.getconf('sep', '.').strip()
 
     def makefolder(self, foldername):
-        self.debug("makefolder called with arg " + repr(foldername))
+        """Create new Maildir folder if necessary
-        # Do the chdir thing so the call to makedirs does not make the
-        # self.root directory (we'd prefer to raise an error in that case),
-        # but will make the (relative) paths underneath it.  Need to use
-        # makedirs to support a / separator.
-        self.debug("Is dir? " + repr(os.path.isdir(foldername)))
-        if self.getsep() == '/':
-            for invalid in ['new', 'cur', 'tmp', 'offlineimap.uidvalidity']:
-                for component in foldername.split('/'):
-                    assert component != invalid, "When using nested folders (/ as a separator in the account config), your folder names may not contain 'new', 'cur', 'tmp', or 'offlineimap.uidvalidity'."
 
-        assert foldername.find('./') == -1, "Folder names may not contain ../"
+        :param foldername: A relative mailbox name. The maildir will be
+            created in self.root+'/'+foldername. All intermediate folder
+            levels will be created if they do not exist yet. 'cur',
+            'tmp', and 'new' subfolders will be created in the maildir.
+        """
+        self.debug("makefolder called with arg '%s'" % (foldername))
+        full_path = os.path.abspath(os.path.join(self.root, foldername))
+    
+        # sanity tests
+        if self.getsep() == '/':
+            for component in foldername.split('/'):
+                assert not component in ['new', 'cur', 'tmp'],\
+                    "When using nested folders (/ as a Maildir separator), "\
+                    "folder names may not contain 'new', 'cur', 'tmp'."
+        assert foldername.find('../') == -1, "Folder names may not contain ../"
         assert not foldername.startswith('/'), "Folder names may not begin with /"
 
-        oldcwd = os.getcwd()
+        # If we're using hierarchical folders, it's possible that
-        os.chdir(self.root)
+        # sub-folders may be created before higher-up ones.
-
+        self.debug("makefolder: calling makedirs '%s'" % full_path)
-        # If we're using hierarchical folders, it's possible that sub-folders
+        try:
-        # may be created before higher-up ones.  If this is the case,
+            os.makedirs(full_path, 0700)
-        # makedirs will fail because the higher-up dir already exists.
+        except OSError, e:
-        # So, check to see if this is indeed the case.
+            if e.errno == 17 and os.path.isdir(full_path):
-
+                self.debug("makefolder: '%s' already a directory" % foldername)
-        if (self.getsep() == '/' or self.getconfboolean('existsok', 0) or foldername == '.') \
+            else:
-            and os.path.isdir(foldername):
+                raise
-            self.debug("makefolder: %s already is a directory" % foldername)
-            # Already exists.  Sanity-check that it's not a Maildir.
-            for subdir in ['cur', 'new', 'tmp']:
-                assert not os.path.isdir(os.path.join(foldername, subdir)), \
-                       "Tried to create folder %s but it already had dir %s" %\
-                       (foldername, subdir)
-        else:
-            self.debug("makefolder: calling makedirs %s" % foldername)
-            assert foldername != '', "Can not create root MailDir."
-            os.makedirs(foldername, 0700)
-        self.debug("makefolder: creating cur, new, tmp")
         for subdir in ['cur', 'new', 'tmp']:
-            os.mkdir(os.path.join(foldername, subdir), 0700)
+            try:
-        # Invalidate the cache
+                os.mkdir(os.path.join(full_path, subdir), 0700)
+            except OSError, e:
+                if e.errno == 17 and os.path.isdir(full_path):
+                    self.debug("makefolder: '%s' already has subdir %s" %
+                               (foldername, sudir))
+                else:
+                    raise
+        # Invalidate the folder cache
         self.folders = None
-        os.chdir(oldcwd)
 
     def deletefolder(self, foldername):
         self.ui.warn("NOT YET IMPLEMENTED: DELETE FOLDER %s" % foldername)
@@ -132,11 +132,11 @@ class MaildirRepository(BaseRepository):
 
         self.debug("  toppath = %s" % toppath)
 
-        # Iterate over directories in top.
+        # Iterate over directories in top & top itself.
-        for dirname in os.listdir(toppath) + ['.']:
+        for dirname in os.listdir(toppath) + [toppath]:
             self.debug("  *** top of loop")
             self.debug("  dirname = %s" % dirname)
-            if dirname in ['cur', 'new', 'tmp', 'offlineimap.uidvalidity']:
+            if dirname in ['cur', 'new', 'tmp']:
                 self.debug("  skipping this dir (Maildir special)")
                 # Bypass special files.
                 continue
@@ -162,7 +162,7 @@ class MaildirRepository(BaseRepository):
                 retval.append(folder.Maildir.MaildirFolder(self.root, foldername,
                                                            self.getsep(), self, self.accountname,
                                                            self.config))
-            if self.getsep() == '/' and dirname != '.':
+            if self.getsep() == '/' and dirname:
                 # Check sub-directories for folders.
                 retval.extend(self._getfolders_scandir(root, foldername))
         self.debug("_GETFOLDERS_SCANDIR RETURNING %s" % \