1 # -*- coding: utf-8 -*-
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.
10 :copyright: (c) 2009 by the Jinja Team.
11 :license: BSD, see LICENSE for more details.
15 from jinja2.utils import CodeType, missing, internal_code
16 from jinja2.exceptions import TemplateSyntaxError
19 class TracebackFrameProxy(object):
20 """Proxies a traceback frame."""
22 def __init__(self, tb):
25 def _set_tb_next(self, next):
26 if tb_set_next is not None:
27 tb_set_next(self.tb, next and next.tb or None)
30 def _get_tb_next(self):
33 tb_next = property(_get_tb_next, _set_tb_next)
34 del _get_tb_next, _set_tb_next
37 def is_jinja_frame(self):
38 return '__jinja_template__' in self.tb.tb_frame.f_globals
40 def __getattr__(self, name):
41 return getattr(self.tb, name)
44 class ProcessedTraceback(object):
45 """Holds a Jinja preprocessed traceback for priting or reraising."""
47 def __init__(self, exc_type, exc_value, frames):
48 assert frames, 'no frames for this traceback?'
49 self.exc_type = exc_type
50 self.exc_value = exc_value
53 def chain_frames(self):
54 """Chains the frames. Requires ctypes or the speedups extension."""
56 for tb in self.frames:
57 if prev_tb is not None:
60 prev_tb.tb_next = None
62 def render_as_text(self, limit=None):
63 """Return a string with the traceback."""
64 lines = traceback.format_exception(self.exc_type, self.exc_value,
65 self.frames[0], limit=limit)
66 return ''.join(lines).rstrip()
68 def render_as_html(self, full=False):
69 """Return a unicode string with the traceback as rendered HTML."""
70 from jinja2.debugrenderer import render_traceback
71 return u'%s\n\n<!--\n%s\n-->' % (
72 render_traceback(self, full=full),
73 self.render_as_text().decode('utf-8', 'replace')
77 def is_template_syntax_error(self):
78 """`True` if this is a template syntax error."""
79 return isinstance(self.exc_value, TemplateSyntaxError)
83 """Exception info tuple with a proxy around the frame objects."""
84 return self.exc_type, self.exc_value, self.frames[0]
87 def standard_exc_info(self):
88 """Standard python exc_info for re-raising"""
89 return self.exc_type, self.exc_value, self.frames[0].tb
92 def make_traceback(exc_info, source_hint=None):
93 """Creates a processed traceback object from the exc_info."""
94 exc_type, exc_value, tb = exc_info
95 if isinstance(exc_value, TemplateSyntaxError):
96 exc_info = translate_syntax_error(exc_value, source_hint)
100 return translate_exception(exc_info, initial_skip)
103 def translate_syntax_error(error, source=None):
104 """Rewrites a syntax error to please traceback systems."""
105 error.source = source
106 error.translated = True
107 exc_info = (type(error), error, None)
108 filename = error.filename
110 filename = '<unknown>'
111 return fake_exc_info(exc_info, filename, error.lineno)
114 def translate_exception(exc_info, initial_skip=0):
115 """If passed an exc_info it will automatically rewrite the exceptions
116 all the way down to the correct line numbers and frames.
121 # skip some internal frames if wanted
122 for x in xrange(initial_skip):
127 while tb is not None:
128 # skip frames decorated with @internalcode. These are internal
129 # calls we can't avoid and that are useless in template debugging
131 if tb.tb_frame.f_code in internal_code:
135 # save a reference to the next frame if we override the current
136 # one with a faked one.
139 # fake template exceptions
140 template = tb.tb_frame.f_globals.get('__jinja_template__')
141 if template is not None:
142 lineno = template.get_corresponding_lineno(tb.tb_lineno)
143 tb = fake_exc_info(exc_info[:2] + (tb,), template.filename,
146 frames.append(TracebackFrameProxy(tb))
149 # if we don't have any exceptions in the frames left, we have to
150 # reraise it unchanged.
151 # XXX: can we backup here? when could this happen?
153 raise exc_info[0], exc_info[1], exc_info[2]
155 traceback = ProcessedTraceback(exc_info[0], exc_info[1], frames)
156 if tb_set_next is not None:
157 traceback.chain_frames()
161 def fake_exc_info(exc_info, filename, lineno):
162 """Helper for `translate_exception`."""
163 exc_type, exc_value, tb = exc_info
165 # figure the real context out
167 real_locals = tb.tb_frame.f_locals.copy()
168 ctx = real_locals.get('context')
170 locals = ctx.get_all()
173 for name, value in real_locals.iteritems():
174 if name.startswith('l_') and value is not missing:
175 locals[name[2:]] = value
177 # if there is a local called __jinja_exception__, we get
178 # rid of it to not break the debug functionality.
179 locals.pop('__jinja_exception__', None)
183 # assamble fake globals we need
185 '__name__': filename,
186 '__file__': filename,
187 '__jinja_exception__': exc_info[:2],
189 # we don't want to keep the reference to the template around
190 # to not cause circular dependencies, but we mark it as Jinja
191 # frame for the ProcessedTraceback
192 '__jinja_template__': None
195 # and fake the exception
196 code = compile('\n' * (lineno - 1) + 'raise __jinja_exception__[0], ' +
197 '__jinja_exception__[1]', filename, 'exec')
199 # if it's possible, change the name of the code. This won't work
200 # on some python environments such as google appengine
203 location = 'template'
205 function = tb.tb_frame.f_code.co_name
206 if function == 'root':
207 location = 'top-level template code'
208 elif function.startswith('block_'):
209 location = 'block "%s"' % function[6:]
211 location = 'template'
212 code = CodeType(0, code.co_nlocals, code.co_stacksize,
213 code.co_flags, code.co_code, code.co_consts,
214 code.co_names, code.co_varnames, filename,
215 location, code.co_firstlineno,
216 code.co_lnotab, (), ())
220 # execute the code and catch the new traceback
222 exec code in globals, locals
224 exc_info = sys.exc_info()
225 new_tb = exc_info[2].tb_next
227 # return without this frame
228 return exc_info[:2] + (new_tb,)
231 def _init_ugly_crap():
232 """This function implements a few ugly things so that we can patch the
233 traceback objects. The function returned allows resetting `tb_next` on
234 any python traceback object.
237 from types import TracebackType
239 # figure out side of _Py_ssize_t
240 if hasattr(ctypes.pythonapi, 'Py_InitModule4_64'):
241 _Py_ssize_t = ctypes.c_int64
243 _Py_ssize_t = ctypes.c_int
246 class _PyObject(ctypes.Structure):
248 _PyObject._fields_ = [
249 ('ob_refcnt', _Py_ssize_t),
250 ('ob_type', ctypes.POINTER(_PyObject))
254 if object.__basicsize__ != ctypes.sizeof(_PyObject):
255 class _PyObject(ctypes.Structure):
257 _PyObject._fields_ = [
258 ('_ob_next', ctypes.POINTER(_PyObject)),
259 ('_ob_prev', ctypes.POINTER(_PyObject)),
260 ('ob_refcnt', _Py_ssize_t),
261 ('ob_type', ctypes.POINTER(_PyObject))
264 class _Traceback(_PyObject):
266 _Traceback._fields_ = [
267 ('tb_next', ctypes.POINTER(_Traceback)),
268 ('tb_frame', ctypes.POINTER(_PyObject)),
269 ('tb_lasti', ctypes.c_int),
270 ('tb_lineno', ctypes.c_int)
273 def tb_set_next(tb, next):
274 """Set the tb_next attribute of a traceback object."""
275 if not (isinstance(tb, TracebackType) and
276 (next is None or isinstance(next, TracebackType))):
277 raise TypeError('tb_set_next arguments must be traceback objects')
278 obj = _Traceback.from_address(id(tb))
279 if tb.tb_next is not None:
280 old = _Traceback.from_address(id(tb.tb_next))
283 obj.tb_next = ctypes.POINTER(_Traceback)()
285 next = _Traceback.from_address(id(next))
287 obj.tb_next = ctypes.pointer(next)
292 # try to get a tb_set_next implementation
294 from jinja2._speedups import tb_set_next
297 tb_set_next = _init_ugly_crap()