Remove the lock around the cookie parsing code.

The locking here was only ever needed for the old `regex` module that was
originally used for this code, but that was replaced by the thread-safe `re`
some 10 years ago (see r20110, april 2001).

doc/CHANGES.rst

@@ -50,6 +50,10 @@ Features Added
 Restructuring
 +++++++++++++
 
+- Removed the (very obsolete) thread lock around the cookie parsing code
+  in HTTPRequest.py; the python `re` module is thread-safe, unlike the
+  ancient `regex` module that was once used here.
+
 - Removed the special handling of `Set-Cookie` headers in
   `HTTPResponse.setHeader`. Use the `setCookie`/`appendCookie`/`expireCookie`
   methods instead, or if low-level control is needed, use `addHeader` instead

src/ZPublisher/HTTPRequest.py

@@ -40,7 +40,6 @@ from AccessControl.tainted import TaintedString
 from ZPublisher.BaseRequest import BaseRequest
 from ZPublisher.BaseRequest import quote
 from ZPublisher.Converters import get_converter
-from ZPublisher.maybe_lock import allocate_lock
 
 # Flags
 SEQUENCE = 1
@@ -1649,7 +1648,6 @@ class FileUpload:
         return self
 
 
-parse_cookie_lock = allocate_lock()
 QPARMRE= re.compile(
         '([\x00- ]*([^\x00- ;,="]+)="([^"]*)"([\x00- ]*[;,])?[\x00- ]*)')
 PARMRE = re.compile(
@@ -1661,16 +1659,11 @@ def parse_cookie(text,
                  qparmre=QPARMRE,
                  parmre=PARMRE,
                  paramlessre=PARAMLESSRE,
-                 acquire=parse_cookie_lock.acquire,
-                 release=parse_cookie_lock.release,
                  ):
 
     if result is None:
         result = {}
 
-    acquire()
-    try:
-
     mo_q = qparmre.match(text)
 
     if mo_q:
@@ -1696,8 +1689,6 @@ def parse_cookie(text,
                 value = ''
             else:
                 return result
-    finally:
-        release()
 
     if name not in result:
         result[name] = unquote(value)