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) 2010 by the Jinja Team.
11 :license: BSD, see LICENSE for more details.
15 from types import TracebackType
16 from jinja2.utils import missing, internal_code
17 from jinja2.exceptions import TemplateSyntaxError
18 from jinja2._compat import iteritems, reraise, code_type
20 # on pypy we can take advantage of transparent proxies
22 from __pypy__ import tproxy
27 # how does the raise helper look like?
29 exec("raise TypeError, 'foo'")
31 raise_helper = 'raise __jinja_exception__[1]'
33 raise_helper = 'raise __jinja_exception__[0], __jinja_exception__[1]'
36 class TracebackFrameProxy(object):
37 """Proxies a traceback frame."""
39 def __init__(self, tb):
47 def set_next(self, next):
48 if tb_set_next is not None:
50 tb_set_next(self.tb, next and next.tb or None)
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.
59 def is_jinja_frame(self):
60 return '__jinja_template__' in self.tb.tb_frame.f_globals
62 def __getattr__(self, name):
63 return getattr(self.tb, name)
66 def make_frame_proxy(frame):
67 proxy = TracebackFrameProxy(frame)
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)
76 return getattr(proxy, operation)(*args, **kwargs)
77 return tproxy(TracebackType, operation_handler)
80 class ProcessedTraceback(object):
81 """Holds a Jinja preprocessed traceback for printing or reraising."""
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
89 # newly concatenate the frames (which are proxies)
91 for tb in self.frames:
92 if prev_tb is not None:
95 prev_tb.set_next(None)
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()
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')
112 def is_template_syntax_error(self):
113 """`True` if this is a template syntax error."""
114 return isinstance(self.exc_value, TemplateSyntaxError)
118 """Exception info tuple with a proxy around the frame objects."""
119 return self.exc_type, self.exc_value, self.frames[0]
122 def standard_exc_info(self):
123 """Standard python exc_info for re-raising"""
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:
129 return self.exc_type, self.exc_value, tb
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)
140 return translate_exception(exc_info, initial_skip)
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
150 filename = '<unknown>'
151 return fake_exc_info(exc_info, filename, error.lineno)
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.
161 # skip some internal frames if wanted
162 for x in range(initial_skip):
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
171 if tb.tb_frame.f_code in internal_code:
175 # save a reference to the next frame if we override the current
176 # one with a faked one.
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,
186 frames.append(make_frame_proxy(tb))
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?
193 reraise(exc_info[0], exc_info[1], exc_info[2])
195 return ProcessedTraceback(exc_info[0], exc_info[1], frames)
198 def fake_exc_info(exc_info, filename, lineno):
199 """Helper for `translate_exception`."""
200 exc_type, exc_value, tb = exc_info
202 # figure the real context out
204 real_locals = tb.tb_frame.f_locals.copy()
205 ctx = real_locals.get('context')
207 locals = ctx.get_all()
210 for name, value in iteritems(real_locals):
211 if name.startswith('l_') and value is not missing:
212 locals[name[2:]] = value
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)
220 # assamble fake globals we need
222 '__name__': filename,
223 '__file__': filename,
224 '__jinja_exception__': exc_info[:2],
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
232 # and fake the exception
233 code = compile('\n' * (lineno - 1) + raise_helper, filename, 'exec')
235 # if it's possible, change the name of the code. This won't work
236 # on some python environments such as google appengine
239 location = 'template'
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:]
247 location = 'template'
248 code = code_type(0, code.co_nlocals, code.co_stacksize,
249 code.co_flags, code.co_code, code.co_consts,
250 code.co_names, code.co_varnames, filename,
251 location, code.co_firstlineno,
252 code.co_lnotab, (), ())
256 # execute the code and catch the new traceback
258 exec(code, globals, locals)
260 exc_info = sys.exc_info()
261 new_tb = exc_info[2].tb_next
263 # return without this frame
264 return exc_info[:2] + (new_tb,)
267 def _init_ugly_crap():
268 """This function implements a few ugly things so that we can patch the
269 traceback objects. The function returned allows resetting `tb_next` on
270 any python traceback object. Do not attempt to use this on non cpython
274 from types import TracebackType
276 # figure out side of _Py_ssize_t
277 if hasattr(ctypes.pythonapi, 'Py_InitModule4_64'):
278 _Py_ssize_t = ctypes.c_int64
280 _Py_ssize_t = ctypes.c_int
283 class _PyObject(ctypes.Structure):
285 _PyObject._fields_ = [
286 ('ob_refcnt', _Py_ssize_t),
287 ('ob_type', ctypes.POINTER(_PyObject))
291 if hasattr(sys, 'getobjects'):
292 class _PyObject(ctypes.Structure):
294 _PyObject._fields_ = [
295 ('_ob_next', ctypes.POINTER(_PyObject)),
296 ('_ob_prev', ctypes.POINTER(_PyObject)),
297 ('ob_refcnt', _Py_ssize_t),
298 ('ob_type', ctypes.POINTER(_PyObject))
301 class _Traceback(_PyObject):
303 _Traceback._fields_ = [
304 ('tb_next', ctypes.POINTER(_Traceback)),
305 ('tb_frame', ctypes.POINTER(_PyObject)),
306 ('tb_lasti', ctypes.c_int),
307 ('tb_lineno', ctypes.c_int)
310 def tb_set_next(tb, next):
311 """Set the tb_next attribute of a traceback object."""
312 if not (isinstance(tb, TracebackType) and
313 (next is None or isinstance(next, TracebackType))):
314 raise TypeError('tb_set_next arguments must be traceback objects')
315 obj = _Traceback.from_address(id(tb))
316 if tb.tb_next is not None:
317 old = _Traceback.from_address(id(tb.tb_next))
320 obj.tb_next = ctypes.POINTER(_Traceback)()
322 next = _Traceback.from_address(id(next))
324 obj.tb_next = ctypes.pointer(next)
329 # try to get a tb_set_next implementation if we don't have transparent
334 tb_set_next = _init_ugly_crap()