a8f06d516be4c943641806ba81ce772ff2d8d189
1 ##############################################################################
2 #
3 # Copyright (c) 2001 Zope Corporation and Contributors. All Rights Reserved.
4 #
5 # This software is subject to the provisions of the Zope Public License,
6 # Version 2.0 (ZPL). A copy of the ZPL should accompany this distribution.
7 # THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
8 # WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
9 # WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
10 # FOR A PARTICULAR PURPOSE
11 #
12 ##############################################################################
14 """Generic Python Expression Handler
16 Modified for Roundup 0.5 release:
18 - more informative traceback info
20 """
22 __version__='$Revision: 1.3 $'[11:-2]
24 from TALES import CompilerError
25 from string import strip, split, join, replace, lstrip
26 from sys import exc_info
28 class getSecurityManager:
29 '''Null security manager'''
30 def validate(self, *args, **kwargs):
31 return 1
32 addContext = removeContext = validateValue = validate
34 class PythonExpr:
35 def __init__(self, name, expr, engine):
36 self.expr = expr = replace(strip(expr), '\n', ' ')
37 try:
38 d = {}
39 exec 'def f():\n return %s\n' % strip(expr) in d
40 self._f = d['f']
41 except:
42 raise CompilerError, ('Python expression error:\n'
43 '%s: %s') % exc_info()[:2]
44 self._get_used_names()
46 def _get_used_names(self):
47 self._f_varnames = vnames = []
48 for vname in self._f.func_code.co_names:
49 if vname[0] not in '$_':
50 vnames.append(vname)
52 def _bind_used_names(self, econtext):
53 # Bind template variables
54 names = {}
55 vars = econtext.vars
56 getType = econtext._engine.getTypes().get
57 for vname in self._f_varnames:
58 has, val = vars.has_get(vname)
59 if not has:
60 has = val = getType(vname)
61 if has:
62 val = ExprTypeProxy(vname, val, econtext)
63 if has:
64 names[vname] = val
65 return names
67 def __call__(self, econtext):
68 __traceback_info__ = 'python expression "%s"'%self.expr
69 f = self._f
70 f.func_globals.update(self._bind_used_names(econtext))
71 return f()
73 def __str__(self):
74 return 'Python expression "%s"' % self.expr
75 def __repr__(self):
76 return '<PythonExpr %s>' % self.expr
78 class ExprTypeProxy:
79 '''Class that proxies access to an expression type handler'''
80 def __init__(self, name, handler, econtext):
81 self._name = name
82 self._handler = handler
83 self._econtext = econtext
84 def __call__(self, text):
85 return self._handler(self._name, text,
86 self._econtext._engine)(self._econtext)