comparison venv/lib/python2.7/site-packages/jinja2/debug.py @ 0:d67268158946 draft

planemo upload commit a3f181f5f126803c654b3a66dd4e83a48f7e203b
author bcclaywell
date Mon, 12 Oct 2015 17:43:33 -0400
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-1:000000000000 0:d67268158946
1 # -*- coding: utf-8 -*-
2 """
3 jinja2.debug
4 ~~~~~~~~~~~~
5
6 Implements the debug interface for Jinja. This module does some pretty
7 ugly stuff with the Python traceback system in order to achieve tracebacks
8 with correct line numbers, locals and contents.
9
10 :copyright: (c) 2010 by the Jinja Team.
11 :license: BSD, see LICENSE for more details.
12 """
13 import sys
14 import traceback
15 from types import TracebackType, CodeType
16 from jinja2.utils import missing, internal_code
17 from jinja2.exceptions import TemplateSyntaxError
18 from jinja2._compat import iteritems, reraise, PY2
19
20 # on pypy we can take advantage of transparent proxies
21 try:
22 from __pypy__ import tproxy
23 except ImportError:
24 tproxy = None
25
26
27 # how does the raise helper look like?
28 try:
29 exec("raise TypeError, 'foo'")
30 except SyntaxError:
31 raise_helper = 'raise __jinja_exception__[1]'
32 except TypeError:
33 raise_helper = 'raise __jinja_exception__[0], __jinja_exception__[1]'
34
35
36 class TracebackFrameProxy(object):
37 """Proxies a traceback frame."""
38
39 def __init__(self, tb):
40 self.tb = tb
41 self._tb_next = None
42
43 @property
44 def tb_next(self):
45 return self._tb_next
46
47 def set_next(self, next):
48 if tb_set_next is not None:
49 try:
50 tb_set_next(self.tb, next and next.tb or None)
51 except Exception:
52 # this function can fail due to all the hackery it does
53 # on various python implementations. We just catch errors
54 # down and ignore them if necessary.
55 pass
56 self._tb_next = next
57
58 @property
59 def is_jinja_frame(self):
60 return '__jinja_template__' in self.tb.tb_frame.f_globals
61
62 def __getattr__(self, name):
63 return getattr(self.tb, name)
64
65
66 def make_frame_proxy(frame):
67 proxy = TracebackFrameProxy(frame)
68 if tproxy is None:
69 return proxy
70 def operation_handler(operation, *args, **kwargs):
71 if operation in ('__getattribute__', '__getattr__'):
72 return getattr(proxy, args[0])
73 elif operation == '__setattr__':
74 proxy.__setattr__(*args, **kwargs)
75 else:
76 return getattr(proxy, operation)(*args, **kwargs)
77 return tproxy(TracebackType, operation_handler)
78
79
80 class ProcessedTraceback(object):
81 """Holds a Jinja preprocessed traceback for printing or reraising."""
82
83 def __init__(self, exc_type, exc_value, frames):
84 assert frames, 'no frames for this traceback?'
85 self.exc_type = exc_type
86 self.exc_value = exc_value
87 self.frames = frames
88
89 # newly concatenate the frames (which are proxies)
90 prev_tb = None
91 for tb in self.frames:
92 if prev_tb is not None:
93 prev_tb.set_next(tb)
94 prev_tb = tb
95 prev_tb.set_next(None)
96
97 def render_as_text(self, limit=None):
98 """Return a string with the traceback."""
99 lines = traceback.format_exception(self.exc_type, self.exc_value,
100 self.frames[0], limit=limit)
101 return ''.join(lines).rstrip()
102
103 def render_as_html(self, full=False):
104 """Return a unicode string with the traceback as rendered HTML."""
105 from jinja2.debugrenderer import render_traceback
106 return u'%s\n\n<!--\n%s\n-->' % (
107 render_traceback(self, full=full),
108 self.render_as_text().decode('utf-8', 'replace')
109 )
110
111 @property
112 def is_template_syntax_error(self):
113 """`True` if this is a template syntax error."""
114 return isinstance(self.exc_value, TemplateSyntaxError)
115
116 @property
117 def exc_info(self):
118 """Exception info tuple with a proxy around the frame objects."""
119 return self.exc_type, self.exc_value, self.frames[0]
120
121 @property
122 def standard_exc_info(self):
123 """Standard python exc_info for re-raising"""
124 tb = self.frames[0]
125 # the frame will be an actual traceback (or transparent proxy) if
126 # we are on pypy or a python implementation with support for tproxy
127 if type(tb) is not TracebackType:
128 tb = tb.tb
129 return self.exc_type, self.exc_value, tb
130
131
132 def make_traceback(exc_info, source_hint=None):
133 """Creates a processed traceback object from the exc_info."""
134 exc_type, exc_value, tb = exc_info
135 if isinstance(exc_value, TemplateSyntaxError):
136 exc_info = translate_syntax_error(exc_value, source_hint)
137 initial_skip = 0
138 else:
139 initial_skip = 1
140 return translate_exception(exc_info, initial_skip)
141
142
143 def translate_syntax_error(error, source=None):
144 """Rewrites a syntax error to please traceback systems."""
145 error.source = source
146 error.translated = True
147 exc_info = (error.__class__, error, None)
148 filename = error.filename
149 if filename is None:
150 filename = '<unknown>'
151 return fake_exc_info(exc_info, filename, error.lineno)
152
153
154 def translate_exception(exc_info, initial_skip=0):
155 """If passed an exc_info it will automatically rewrite the exceptions
156 all the way down to the correct line numbers and frames.
157 """
158 tb = exc_info[2]
159 frames = []
160
161 # skip some internal frames if wanted
162 for x in range(initial_skip):
163 if tb is not None:
164 tb = tb.tb_next
165 initial_tb = tb
166
167 while tb is not None:
168 # skip frames decorated with @internalcode. These are internal
169 # calls we can't avoid and that are useless in template debugging
170 # output.
171 if tb.tb_frame.f_code in internal_code:
172 tb = tb.tb_next
173 continue
174
175 # save a reference to the next frame if we override the current
176 # one with a faked one.
177 next = tb.tb_next
178
179 # fake template exceptions
180 template = tb.tb_frame.f_globals.get('__jinja_template__')
181 if template is not None:
182 lineno = template.get_corresponding_lineno(tb.tb_lineno)
183 tb = fake_exc_info(exc_info[:2] + (tb,), template.filename,
184 lineno)[2]
185
186 frames.append(make_frame_proxy(tb))
187 tb = next
188
189 # if we don't have any exceptions in the frames left, we have to
190 # reraise it unchanged.
191 # XXX: can we backup here? when could this happen?
192 if not frames:
193 reraise(exc_info[0], exc_info[1], exc_info[2])
194
195 return ProcessedTraceback(exc_info[0], exc_info[1], frames)
196
197
198 def fake_exc_info(exc_info, filename, lineno):
199 """Helper for `translate_exception`."""
200 exc_type, exc_value, tb = exc_info
201
202 # figure the real context out
203 if tb is not None:
204 real_locals = tb.tb_frame.f_locals.copy()
205 ctx = real_locals.get('context')
206 if ctx:
207 locals = ctx.get_all()
208 else:
209 locals = {}
210 for name, value in iteritems(real_locals):
211 if name.startswith('l_') and value is not missing:
212 locals[name[2:]] = value
213
214 # if there is a local called __jinja_exception__, we get
215 # rid of it to not break the debug functionality.
216 locals.pop('__jinja_exception__', None)
217 else:
218 locals = {}
219
220 # assamble fake globals we need
221 globals = {
222 '__name__': filename,
223 '__file__': filename,
224 '__jinja_exception__': exc_info[:2],
225
226 # we don't want to keep the reference to the template around
227 # to not cause circular dependencies, but we mark it as Jinja
228 # frame for the ProcessedTraceback
229 '__jinja_template__': None
230 }
231
232 # and fake the exception
233 code = compile('\n' * (lineno - 1) + raise_helper, filename, 'exec')
234
235 # if it's possible, change the name of the code. This won't work
236 # on some python environments such as google appengine
237 try:
238 if tb is None:
239 location = 'template'
240 else:
241 function = tb.tb_frame.f_code.co_name
242 if function == 'root':
243 location = 'top-level template code'
244 elif function.startswith('block_'):
245 location = 'block "%s"' % function[6:]
246 else:
247 location = 'template'
248
249 if PY2:
250 code = CodeType(0, code.co_nlocals, code.co_stacksize,
251 code.co_flags, code.co_code, code.co_consts,
252 code.co_names, code.co_varnames, filename,
253 location, code.co_firstlineno,
254 code.co_lnotab, (), ())
255 else:
256 code = CodeType(0, code.co_kwonlyargcount,
257 code.co_nlocals, code.co_stacksize,
258 code.co_flags, code.co_code, code.co_consts,
259 code.co_names, code.co_varnames, filename,
260 location, code.co_firstlineno,
261 code.co_lnotab, (), ())
262 except Exception as e:
263 pass
264
265 # execute the code and catch the new traceback
266 try:
267 exec(code, globals, locals)
268 except:
269 exc_info = sys.exc_info()
270 new_tb = exc_info[2].tb_next
271
272 # return without this frame
273 return exc_info[:2] + (new_tb,)
274
275
276 def _init_ugly_crap():
277 """This function implements a few ugly things so that we can patch the
278 traceback objects. The function returned allows resetting `tb_next` on
279 any python traceback object. Do not attempt to use this on non cpython
280 interpreters
281 """
282 import ctypes
283 from types import TracebackType
284
285 if PY2:
286 # figure out size of _Py_ssize_t for Python 2:
287 if hasattr(ctypes.pythonapi, 'Py_InitModule4_64'):
288 _Py_ssize_t = ctypes.c_int64
289 else:
290 _Py_ssize_t = ctypes.c_int
291 else:
292 # platform ssize_t on Python 3
293 _Py_ssize_t = ctypes.c_ssize_t
294
295 # regular python
296 class _PyObject(ctypes.Structure):
297 pass
298 _PyObject._fields_ = [
299 ('ob_refcnt', _Py_ssize_t),
300 ('ob_type', ctypes.POINTER(_PyObject))
301 ]
302
303 # python with trace
304 if hasattr(sys, 'getobjects'):
305 class _PyObject(ctypes.Structure):
306 pass
307 _PyObject._fields_ = [
308 ('_ob_next', ctypes.POINTER(_PyObject)),
309 ('_ob_prev', ctypes.POINTER(_PyObject)),
310 ('ob_refcnt', _Py_ssize_t),
311 ('ob_type', ctypes.POINTER(_PyObject))
312 ]
313
314 class _Traceback(_PyObject):
315 pass
316 _Traceback._fields_ = [
317 ('tb_next', ctypes.POINTER(_Traceback)),
318 ('tb_frame', ctypes.POINTER(_PyObject)),
319 ('tb_lasti', ctypes.c_int),
320 ('tb_lineno', ctypes.c_int)
321 ]
322
323 def tb_set_next(tb, next):
324 """Set the tb_next attribute of a traceback object."""
325 if not (isinstance(tb, TracebackType) and
326 (next is None or isinstance(next, TracebackType))):
327 raise TypeError('tb_set_next arguments must be traceback objects')
328 obj = _Traceback.from_address(id(tb))
329 if tb.tb_next is not None:
330 old = _Traceback.from_address(id(tb.tb_next))
331 old.ob_refcnt -= 1
332 if next is None:
333 obj.tb_next = ctypes.POINTER(_Traceback)()
334 else:
335 next = _Traceback.from_address(id(next))
336 next.ob_refcnt += 1
337 obj.tb_next = ctypes.pointer(next)
338
339 return tb_set_next
340
341
342 # try to get a tb_set_next implementation if we don't have transparent
343 # proxies.
344 tb_set_next = None
345 if tproxy is None:
346 try:
347 tb_set_next = _init_ugly_crap()
348 except:
349 pass
350 del _init_ugly_crap