Make folders containing quotes work

imaputil.imapsplit did not cope with strings that contained encoded
quotation marks, e.g. a folder name '"Make" Magazine' would fail and
crash OfflineImap. Make it work by adapting the regex that we use to
extract the first quote to also work with encoded \" quotes. (We do no
sanity checks that there is an even number of such marks within a string
though)

This commit makes such folders work. This was reported and analyzed by
Mark Eichin.

Signed-off-by: Sebastian Spaeth <Sebastian@SSpaeth.de>

Changelog.draft.rst

@@ -13,6 +13,9 @@ others.
 New Features
 ------------
 
+* Make folders containing quotes work rather than crashing
+  (reported by Mark Eichin)
+
 Changes
 -------
 

offlineimap/imaputil.py

@@ -25,7 +25,12 @@ try: # python 2.6 has set() built in
 except NameError:
     from sets import Set as set
 
-quotere = re.compile('^("(?:[^"]|\\\\")*")')
+# find the first quote in a string
+quotere = re.compile(
+    r"""(?P<quote>"(?:\\"|[^"])*") # Quote, possibly containing encoded
+                                   # quotation mark
+        \s*(?P<rest>.*)$           # Whitespace & remainder of string""",
+    re.VERBOSE)
 
 def debug(*args):
     msg = []
@@ -71,7 +76,7 @@ def options2hash(list):
 
 def flags2hash(flags):
     """Converts IMAP response string from eg IMAP4.fetch() to a hash.
-    
+
     E.g. '(FLAGS (\\Seen Old) UID 4807)' leads to
     {'FLAGS': '(\\Seen Old)', 'UID': '4807'}"""
     return options2hash(flagsplit(flags))
@@ -124,10 +129,11 @@ def imapsplit(imapstring):
                 retval.extend(imapsplit(arg))
         debug("imapsplit() non-string: returning %s" % str(retval))
         return retval
-        
+
     workstr = imapstring.strip()
     retval = []
     while len(workstr):
+        # handle parenthized fragments (...()...)
         if workstr[0] == '(':
             rparenc = 1 # count of right parenthesis to match
             rpareni = 1 # position to examine
@@ -141,9 +147,10 @@ def imapsplit(imapstring):
             workstr = workstr[rpareni:].lstrip()
             retval.append(parenlist)
         elif workstr[0] == '"':
-            quotelist = quotere.search(workstr).group(1)
-            workstr = workstr[len(quotelist):].lstrip()
-            retval.append(quotelist)
+            # quoted fragments '"...\"..."'
+            m = quotere.match(workstr)
+            retval.append(m.group('quote'))
+            workstr = m.group('rest')
         else:
             splits = string.split(workstr, maxsplit = 1)
             splitslen = len(splits)
@@ -161,8 +168,9 @@ def imapsplit(imapstring):
             elif splitslen == 0:
                 # There was not even an unquoted word.
                 break
+    getglobalui().warn("%s->%s" % (imapstring, retval))
     return retval
-            
+
 flagmap = [('\\Seen', 'S'),
            ('\\Answered', 'R'),
            ('\\Flagged', 'F'),