This file is indexed.

/usr/share/pyshared/zope/tales/expressions.py is in python-zope.tales 3.5.3-0ubuntu1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
##############################################################################
#
# Copyright (c) 2001, 2002 Zope Foundation and Contributors.
# All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.
#
##############################################################################
"""Basic Page Template expression types.

$Id: expressions.py 126816 2012-06-11 19:00:21Z tseaver $
"""
import re, types

from zope.interface import implements
from zope.tales.tales import _valid_name, _parse_expr, NAME_RE, Undefined
from zope.tales.interfaces import ITALESExpression, ITALESFunctionNamespace

Undefs = (Undefined, AttributeError, LookupError, TypeError)

_marker = object()
namespace_re = re.compile(r'(\w+):(.+)')

def simpleTraverse(object, path_items, econtext):
    """Traverses a sequence of names, first trying attributes then items.
    """

    for name in path_items:
        next = getattr(object, name, _marker)
        if next is not _marker:
            object = next
        elif hasattr(object, '__getitem__'):
            object = object[name]
        else:
            # Allow AttributeError to propagate
            object = getattr(object, name)
    return object


class SubPathExpr(object):

    def __init__(self, path, traverser, engine):
        self._traverser = traverser
        self._engine = engine

        # Parse path
        compiledpath = []
        currentpath = []
        for element in str(path).strip().split('/'):
            if not element:
                raise engine.getCompilerError()(
                    'Path element may not be empty in %r' % path)
            if element.startswith('?'):
                if currentpath:
                    compiledpath.append(tuple(currentpath))
                    currentpath = []
                if not _valid_name(element[1:]):
                    raise engine.getCompilerError()(
                        'Invalid variable name "%s"' % element[1:])
                compiledpath.append(element[1:])
            else:
                match = namespace_re.match(element)
                if match:
                    if currentpath:
                        compiledpath.append(tuple(currentpath))
                        currentpath = []
                    namespace, functionname = match.groups()
                    if not _valid_name(namespace):
                        raise engine.getCompilerError()(
                            'Invalid namespace name "%s"' % namespace)
                    try:
                        compiledpath.append(
                            self._engine.getFunctionNamespace(namespace))
                    except KeyError:
                        raise engine.getCompilerError()(
                            'Unknown namespace "%s"' % namespace)
                    currentpath.append(functionname)
                else:
                    currentpath.append(element)

        if currentpath:
            compiledpath.append(tuple(currentpath))

        first = compiledpath[0]
        base = first[0]

        if callable(first):
            # check for initial function
            raise engine.getCompilerError()(
                'Namespace function specified in first subpath element')
        elif isinstance(first, basestring):
            # check for initial ?
            raise engine.getCompilerError()(
                'Dynamic name specified in first subpath element')

        if base and not _valid_name(base):
            raise engine.getCompilerError()(
                'Invalid variable name "%s"' % element)
        self._base = base
        compiledpath[0] = first[1:]
        self._compiled_path = tuple(compiledpath)

    def _eval(self, econtext,
              isinstance=isinstance):
        vars = econtext.vars

        compiled_path = self._compiled_path

        base = self._base
        if base == 'CONTEXTS' or not base:  # Special base name
            ob = econtext.contexts
        else:
            ob = vars[base]
        if isinstance(ob, DeferWrapper):
            ob = ob()

        for element in compiled_path:
            if isinstance(element, tuple):
                ob = self._traverser(ob, element, econtext)
            elif isinstance(element, basestring):
                val = vars[element]
                # If the value isn't a string, assume it's a sequence
                # of path names.
                if isinstance(val, basestring):
                    val = (val,)
                ob = self._traverser(ob, val, econtext)
            elif callable(element):
                ob = element(ob)
                # TODO: Once we have n-ary adapters, use them.
                if ITALESFunctionNamespace.providedBy(ob):
                    ob.setEngine(econtext)
            else:
                raise ValueError(repr(element))
        return ob


class PathExpr(object):
    """One or more subpath expressions, separated by '|'."""
    implements(ITALESExpression)

    # _default_type_names contains the expression type names this
    # class is usually registered for.
    _default_type_names = (
        'standard',
        'path',
        'exists',
        'nocall',
        )

    def __init__(self, name, expr, engine, traverser=simpleTraverse):
        self._s = expr
        self._name = name
        self._hybrid = False
        paths = expr.split('|')
        self._subexprs = []
        add = self._subexprs.append
        for i in range(len(paths)):
            path = paths[i].lstrip()
            if _parse_expr(path):
                # This part is the start of another expression type,
                # so glue it back together and compile it.
                add(engine.compile('|'.join(paths[i:]).lstrip()))
                self._hybrid = True
                break
            add(SubPathExpr(path, traverser, engine)._eval)

    def _exists(self, econtext):
        for expr in self._subexprs:
            try:
                expr(econtext)
            except Undefs:
                pass
            else:
                return 1
        return 0

    def _eval(self, econtext):
        for expr in self._subexprs[:-1]:
            # Try all but the last subexpression, skipping undefined ones.
            try:
                ob = expr(econtext)
            except Undefs:
                pass
            else:
                break
        else:
            # On the last subexpression allow exceptions through, and
            # don't autocall if the expression was not a subpath.
            ob = self._subexprs[-1](econtext)
            if self._hybrid:
                return ob

        if self._name == 'nocall':
            return ob

        # Call the object if it is callable.  Note that checking for
        # callable() isn't safe because the object might be security
        # proxied (and security proxies report themselves callable, no
        # matter what the underlying object is).  We therefore check
        # for the __call__ attribute, but not with hasattr as that
        # eats babies, err, exceptions.  In addition to that, we
        # support calling old style classes which don't have a
        # __call__.
        if (getattr(ob, '__call__', _marker) is not _marker
            or isinstance(ob, types.ClassType)):
            return ob()
        return ob

    def __call__(self, econtext):
        if self._name == 'exists':
            return self._exists(econtext)
        return self._eval(econtext)

    def __str__(self):
        return '%s expression (%s)' % (self._name, `self._s`)

    def __repr__(self):
        return '<PathExpr %s:%s>' % (self._name, `self._s`)



_interp = re.compile(
        r'\$(%(n)s)|\${(%(n)s(?:/[^}|]*)*(?:\|%(n)s(?:/[^}|]*)*)*)}'
            % {'n': NAME_RE})

class StringExpr(object):
    implements(ITALESExpression)

    def __init__(self, name, expr, engine):
        self._s = expr
        if '%' in expr:
            expr = expr.replace('%', '%%')
        self._vars = vars = []
        if '$' in expr:
            # Use whatever expr type is registered as "path".
            path_type = engine.getTypes()['path']
            parts = []
            for exp in expr.split('$$'):
                if parts: parts.append('$')
                m = _interp.search(exp)
                while m is not None:
                    parts.append(exp[:m.start()])
                    parts.append('%s')
                    vars.append(path_type(
                        'path', m.group(1) or m.group(2), engine))
                    exp = exp[m.end():]
                    m = _interp.search(exp)
                if '$' in exp:
                    raise engine.getCompilerError()(
                        '$ must be doubled or followed by a simple path')
                parts.append(exp)
            expr = ''.join(parts)
        self._expr = expr

    def __call__(self, econtext):
        vvals = []
        for var in self._vars:
            v = var(econtext)
            vvals.append(v)
        return self._expr % tuple(vvals)

    def __str__(self):
        return 'string expression (%s)' % `self._s`

    def __repr__(self):
        return '<StringExpr %s>' % `self._s`


class NotExpr(object):
    implements(ITALESExpression)

    def __init__(self, name, expr, engine):
        self._s = expr = expr.lstrip()
        self._c = engine.compile(expr)

    def __call__(self, econtext):
        return int(not econtext.evaluateBoolean(self._c))

    def __repr__(self):
        return '<NotExpr %s>' % `self._s`


class DeferWrapper(object):
    def __init__(self, expr, econtext):
        self._expr = expr
        self._econtext = econtext

    def __str__(self):
        return str(self())

    def __call__(self):
        return self._expr(self._econtext)


class DeferExpr(object):
    implements(ITALESExpression)

    def __init__(self, name, expr, compiler):
        self._s = expr = expr.lstrip()
        self._c = compiler.compile(expr)

    def __call__(self, econtext):
        return DeferWrapper(self._c, econtext)

    def __repr__(self):
        return '<DeferExpr %s>' % `self._s`


class LazyWrapper(DeferWrapper):
    """Wrapper for lazy: expression
    """
    def __init__(self, expr, econtext):
        DeferWrapper.__init__(self, expr, econtext)
        self._result = _marker

    def __call__(self):
        r = self._result
        if r is _marker:
            self._result = r = self._expr(self._econtext)
        return r

class LazyExpr(DeferExpr):
    """lazy: expression handler for lazy initialization of expressions
    """
    def __call__(self, econtext):
        return LazyWrapper(self._c, econtext)

    def __repr__(self):
        return 'lazy:%s' % `self._s`


class SimpleModuleImporter(object):
    """Minimal module importer with no security."""

    def __getitem__(self, module):
        mod = self._get_toplevel_module(module)
        path = module.split('.')
        for name in path[1:]:
            mod = getattr(mod, name)
        return mod

    def _get_toplevel_module(self, module):
        # This can be overridden to add security proxies.
        return __import__(module)