ZMySQLDA: accept 'db@unix_socket ...' syntax for connection strings

This deprecates the old syntax, which uselessly requires to specify credentials.

product/ZMySQLDA/connectionAdd.dtml

@@ -49,7 +49,7 @@
     The connection string used for Z MySQL Database Connection
     is of the form:
 <pre>
-    [~] [*lock] [+/-][database][@host[:port]] [user [password [unix_socket]]]
+    [~] [*lock] [+|-][database][@unix_socket|@host[:port]] [user [password]]
 </pre>
     or typically:
 <pre>
@@ -61,10 +61,8 @@
     port on the local system, use 127.0.0.1 for the host instead of
     localhost.
 <p>
-    Either a database or a host or both must be specified.
-<p>
-    If the UNIX socket is in a non-standard location, you can specify
-    the full path to it after the password.
+    IPv6 are supported and must be surrounded with brackets.
+    A UNIX socket absolute path can be specified in place of a TCP address.
 <p>
     A '-' in front of the database tells ZMySQLDA to not use Zope's
     Transaction Manager, even if the server supports transactions. A

product/ZMySQLDA/db.py

@@ -86,8 +86,10 @@
 '''$Id: db.py,v 1.20 2002/03/14 20:24:54 adustman Exp $'''
 __version__='$Revision: 1.20 $'[11:-2]
 
+import os
 import _mysql
 import MySQLdb
+import warnings
 from _mysql_exceptions import OperationalError, NotSupportedError, ProgrammingError
 MySQLdb_version_required = (0,9,2)
 
@@ -205,14 +207,17 @@ class DB(TM):
         db = items.pop(0)
         if '@' in db:
             db, host = db.split('@', 1)
-            if host.startswith('['):
-                host, port = host[1:].split(']', 1)
-                if port.startswith(':'):
-                  kwargs['port'] = int(port[1:])
-            elif ':' in host:
-                host, port = host.split(':', 1)
-                kwargs['port'] = int(port)
-            kwargs['host'] = host
+            if os.path.isabs(host):
+                kwargs['unix_socket'] = host
+            else:
+                if host.startswith('['):
+                    host, port = host[1:].split(']', 1)
+                    if port.startswith(':'):
+                      kwargs['port'] = int(port[1:])
+                elif ':' in host:
+                    host, port = host.split(':', 1)
+                    kwargs['port'] = int(port)
+                kwargs['host'] = host
         if db:
             if db[0] in '+-':
                 self._try_transactions = db[0]
@@ -223,7 +228,10 @@ class DB(TM):
             kwargs['user'] = items.pop(0)
             if items:
                 kwargs['passwd'] = items.pop(0)
-                if items:
+                if items: # BBB
+                    assert 'unix_socket' not in kwargs
+                    warnings.warn("use '<db>@<unix_socket> ...' syntax instead",
+                                  DeprecationWarning)
                     kwargs['unix_socket'] = items.pop(0)
 
     defs={