1 from __future__ import unicode_literals
2
3 import itertools
4 import json
5 import math
6 import operator
7 import re
8
9 from .utils import (
10 ExtractorError,
11 js_to_json,
12 remove_quotes,
13 unified_timestamp,
14 )
15 from .compat import (
16 compat_collections_chain_map as ChainMap,
17 compat_itertools_zip_longest as zip_longest,
18 compat_str,
19 )
20
21 _NAME_RE = r'[a-zA-Z_$][\w$]*'
22
23 _UNDEFINED = object()
24
25
26 def _js_bit_op(op):
27
28 def wrapped(a, b):
29 def zeroise(x):
30 return 0 if x in (None, _UNDEFINED) else x
31 return op(zeroise(a), zeroise(b))
32
33 return wrapped
34
35
36 def _js_arith_op(op):
37
38 def wrapped(a, b):
39 if _UNDEFINED in (a, b):
40 return float('nan')
41 return op(a or 0, b or 0)
42
43 return wrapped
44
45
46 def _js_div(a, b):
47 if _UNDEFINED in (a, b) or not (a and b):
48 return float('nan')
49 return float('inf') if not b else operator.truediv(a or 0, b)
50
51
52 def _js_mod(a, b):
53 if _UNDEFINED in (a, b) or not b:
54 return float('nan')
55 return (a or 0) % b
56
57
58 def _js_exp(a, b):
59 if not b:
60 # even 0 ** 0 !!
61 return 1
62 if _UNDEFINED in (a, b):
63 return float('nan')
64 return (a or 0) ** b
65
66
67 def _js_eq_op(op):
68
69 def wrapped(a, b):
70 if set((a, b)) <= set((None, _UNDEFINED)):
71 return op(a, a)
72 return op(a, b)
73
74 return wrapped
75
76
77 def _js_comp_op(op):
78
79 def wrapped(a, b):
80 if _UNDEFINED in (a, b):
81 return False
82 return op(a or 0, b or 0)
83
84 return wrapped
85
86
87 # (op, definition) in order of binding priority, tightest first
88 # avoid dict to maintain order
89 # definition None => Defined in JSInterpreter._operator
90 _DOT_OPERATORS = (
91 ('.', None),
92 # TODO: ('?.', None),
93 )
94
95 _OPERATORS = (
96 ('>>', _js_bit_op(operator.rshift)),
97 ('<<', _js_bit_op(operator.lshift)),
98 ('+', _js_arith_op(operator.add)),
99 ('-', _js_arith_op(operator.sub)),
100 ('*', _js_arith_op(operator.mul)),
101 ('/', _js_div),
102 ('%', _js_mod),
103 ('**', _js_exp),
104 )
105
106 _COMP_OPERATORS = (
107 ('===', operator.is_),
108 ('==', _js_eq_op(operator.eq)),
109 ('!==', operator.is_not),
110 ('!=', _js_eq_op(operator.ne)),
111 ('<=', _js_comp_op(operator.le)),
112 ('>=', _js_comp_op(operator.ge)),
113 ('<', _js_comp_op(operator.lt)),
114 ('>', _js_comp_op(operator.gt)),
115 )
116
117 _LOG_OPERATORS = (
118 ('|', _js_bit_op(operator.or_)),
119 ('^', _js_bit_op(operator.xor)),
120 ('&', _js_bit_op(operator.and_)),
121 )
122
123 _SC_OPERATORS = (
124 ('?', None),
125 ('??', None),
126 ('||', None),
127 ('&&', None),
128 )
129
130 _OPERATOR_RE = '|'.join(map(lambda x: re.escape(x[0]), _OPERATORS + _LOG_OPERATORS))
131
132 _MATCHING_PARENS = dict(zip(*zip('()', '{}', '[]')))
133 _QUOTES = '\'"'
134
135
136 def _ternary(cndn, if_true=True, if_false=False):
137 """Simulate JS's ternary operator (cndn?if_true:if_false)"""
138 if cndn in (False, None, 0, '', _UNDEFINED):
139 return if_false
140 try:
141 if math.isnan(cndn): # NB: NaN cannot be checked by membership
142 return if_false
143 except TypeError:
144 pass
145 return if_true
146
147
148 class JS_Break(ExtractorError):
149 def __init__(self):
150 ExtractorError.__init__(self, 'Invalid break')
151
152
153 class JS_Continue(ExtractorError):
154 def __init__(self):
155 ExtractorError.__init__(self, 'Invalid continue')
156
157
158 class LocalNameSpace(ChainMap):
159 def __getitem__(self, key):
160 try:
161 return super(LocalNameSpace, self).__getitem__(key)
162 except KeyError:
163 return _UNDEFINED
164
165 def __setitem__(self, key, value):
166 for scope in self.maps:
167 if key in scope:
168 scope[key] = value
169 return
170 self.maps[0][key] = value
171
172 def __delitem__(self, key):
173 raise NotImplementedError('Deleting is not supported')
174
175 def __contains__(self, key):
176 try:
177 super(LocalNameSpace, self).__getitem__(key)
178 return True
179 except KeyError:
180 return False
181
182 def __repr__(self):
183 return 'LocalNameSpace%s' % (self.maps, )
184
185
186 class JSInterpreter(object):
187 __named_object_counter = 0
188
189 undefined = _UNDEFINED
190
191 def __init__(self, code, objects=None):
192 self.code, self._functions = code, {}
193 self._objects = {} if objects is None else objects
194
195 class Exception(ExtractorError):
196 def __init__(self, msg, *args, **kwargs):
197 expr = kwargs.pop('expr', None)
198 if expr is not None:
199 msg = '{0} in: {1!r}'.format(msg.rstrip(), expr[:100])
200 super(JSInterpreter.Exception, self).__init__(msg, *args, **kwargs)
201
202 def _named_object(self, namespace, obj):
203 self.__named_object_counter += 1
204 name = '__youtube_dl_jsinterp_obj%d' % (self.__named_object_counter, )
205 namespace[name] = obj
206 return name
207
208 @staticmethod
209 def _separate(expr, delim=',', max_split=None, skip_delims=None):
210 if not expr:
211 return
212 counters = {k: 0 for k in _MATCHING_PARENS.values()}
213 start, splits, pos, skipping, delim_len = 0, 0, 0, 0, len(delim) - 1
214 in_quote, escaping = None, False
215 for idx, char in enumerate(expr):
216 if not in_quote:
217 if char in _MATCHING_PARENS:
218 counters[_MATCHING_PARENS[char]] += 1
219 elif char in counters:
220 counters[char] -= 1
221 if not escaping:
222 if char in _QUOTES and in_quote in (char, None):
223 in_quote = None if in_quote else char
224 else:
225 escaping = in_quote and char == '\\'
226 else:
227 escaping = False
228
229 if char != delim[pos] or any(counters.values()) or in_quote:
230 pos = skipping = 0
231 continue
232 elif skipping > 0:
233 skipping -= 1
234 continue
235 elif pos == 0 and skip_delims:
236 here = expr[idx:]
237 for s in skip_delims if isinstance(skip_delims, (list, tuple)) else [skip_delims]:
238 if here.startswith(s) and s:
239 skipping = len(s) - 1
240 break
241 if skipping > 0:
242 continue
243 if pos < delim_len:
244 pos += 1
245 continue
246 yield expr[start: idx - delim_len]
247 start, pos = idx + 1, 0
248 splits += 1
249 if max_split and splits >= max_split:
250 break
251 yield expr[start:]
252
253 @classmethod
254 def _separate_at_paren(cls, expr, delim):
255 separated = list(cls._separate(expr, delim, 1))
256
257 if len(separated) < 2:
258 raise cls.Exception('No terminating paren {delim} in {expr}'.format(**locals()))
259 return separated[0][1:].strip(), separated[1].strip()
260
261 @staticmethod
262 def _all_operators():
263 return itertools.chain(
264 # Ref: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Operator_Precedence
265 _SC_OPERATORS, _LOG_OPERATORS, _COMP_OPERATORS, _OPERATORS)
266
267 def _operator(self, op, left_val, right_expr, expr, local_vars, allow_recursion):
268 if op in ('||', '&&'):
269 if (op == '&&') ^ _ternary(left_val):
270 return left_val # short circuiting
271 elif op == '??':
272 if left_val not in (None, self.undefined):
273 return left_val
274 elif op == '?':
275 right_expr = _ternary(left_val, *self._separate(right_expr, ':', 1))
276
277 right_val = self.interpret_expression(right_expr, local_vars, allow_recursion)
278 opfunc = op and next((v for k, v in self._all_operators() if k == op), None)
279 if not opfunc:
280 return right_val
281
282 try:
283 return opfunc(left_val, right_val)
284 except Exception as e:
285 raise self.Exception('Failed to evaluate {left_val!r} {op} {right_val!r}'.format(**locals()), expr, cause=e)
286
287 def _index(self, obj, idx, allow_undefined=False):
288 if idx == 'length':
289 return len(obj)
290 try:
291 return obj[int(idx)] if isinstance(obj, list) else obj[idx]
292 except Exception as e:
293 if allow_undefined:
294 return self.undefined
295 raise self.Exception('Cannot get index {idx}'.format(**locals()), expr=repr(obj), cause=e)
296
297 def _dump(self, obj, namespace):
298 try:
299 return json.dumps(obj)
300 except TypeError:
301 return self._named_object(namespace, obj)
302
303 def interpret_statement(self, stmt, local_vars, allow_recursion=100):
304 if allow_recursion < 0:
305 raise self.Exception('Recursion limit reached')
306 allow_recursion -= 1
307
308 should_return = False
309 sub_statements = list(self._separate(stmt, ';')) or ['']
310 expr = stmt = sub_statements.pop().strip()
311 for sub_stmt in sub_statements:
312 ret, should_return = self.interpret_statement(sub_stmt, local_vars, allow_recursion)
313 if should_return:
314 return ret, should_return
315
316 m = re.match(r'(?P<var>(?:var|const|let)\s)|return(?:\s+|$)', stmt)
317 if m:
318 expr = stmt[len(m.group(0)):].strip()
319 should_return = not m.group('var')
320 if not expr:
321 return None, should_return
322
323 if expr[0] in _QUOTES:
324 inner, outer = self._separate(expr, expr[0], 1)
325 inner = json.loads(js_to_json(inner + expr[0])) # , strict=True))
326 if not outer:
327 return inner, should_return
328 expr = self._named_object(local_vars, inner) + outer
329
330 if expr.startswith('new '):
331 obj = expr[4:]
332 if obj.startswith('Date('):
333 left, right = self._separate_at_paren(obj[4:], ')')
334 expr = unified_timestamp(
335 self.interpret_expression(left, local_vars, allow_recursion), False)
336 if not expr:
337 raise self.Exception('Failed to parse date {left!r}'.format(**locals()), expr=expr)
338 expr = self._dump(int(expr * 1000), local_vars) + right
339 else:
340 raise self.Exception('Unsupported object {obj}'.format(**locals()), expr=expr)
341
342 if expr.startswith('void '):
343 left = self.interpret_expression(expr[5:], local_vars, allow_recursion)
344 return None, should_return
345
346 if expr.startswith('{'):
347 inner, outer = self._separate_at_paren(expr, '}')
348 # try for object expression
349 sub_expressions = [list(self._separate(sub_expr.strip(), ':', 1)) for sub_expr in self._separate(inner)]
350 if all(len(sub_expr) == 2 for sub_expr in sub_expressions):
351 return dict(
352 (key_expr if re.match(_NAME_RE, key_expr) else key_expr,
353 self.interpret_expression(val_expr, local_vars, allow_recursion))
354 for key_expr, val_expr in sub_expressions), should_return
355 # or statement list
356 inner, should_abort = self.interpret_statement(inner, local_vars, allow_recursion)
357 if not outer or should_abort:
358 return inner, should_abort or should_return
359 else:
360 expr = self._dump(inner, local_vars) + outer
361
362 if expr.startswith('('):
363 inner, outer = self._separate_at_paren(expr, ')')
364 inner, should_abort = self.interpret_statement(inner, local_vars, allow_recursion)
365 if not outer or should_abort:
366 return inner, should_abort or should_return
367 else:
368 expr = self._dump(inner, local_vars) + outer
369
370 if expr.startswith('['):
371 inner, outer = self._separate_at_paren(expr, ']')
372 name = self._named_object(local_vars, [
373 self.interpret_expression(item, local_vars, allow_recursion)
374 for item in self._separate(inner)])
375 expr = name + outer
376
377 m = re.match(r'(?P<try>try|finally)\s*|(?:(?P<catch>catch)|(?P<for>for)|(?P<switch>switch))\s*\(', expr)
378 md = m.groupdict() if m else {}
379 if md.get('try'):
380 if expr[m.end()] == '{':
381 try_expr, expr = self._separate_at_paren(expr[m.end():], '}')
382 else:
383 try_expr, expr = expr[m.end() - 1:], ''
384 ret, should_abort = self.interpret_statement(try_expr, local_vars, allow_recursion)
385 if should_abort:
386 return ret, True
387 ret, should_abort = self.interpret_statement(expr, local_vars, allow_recursion)
388 return ret, should_abort or should_return
389
390 elif md.get('catch'):
391 # We ignore the catch block
392 _, expr = self._separate_at_paren(expr, '}')
393 ret, should_abort = self.interpret_statement(expr, local_vars, allow_recursion)
394 return ret, should_abort or should_return
395
396 elif md.get('for'):
397 constructor, remaining = self._separate_at_paren(expr[m.end() - 1:], ')')
398 if remaining.startswith('{'):
399 body, expr = self._separate_at_paren(remaining, '}')
400 else:
401 switch_m = re.match(r'switch\s*\(', remaining) # FIXME
402 if switch_m:
403 switch_val, remaining = self._separate_at_paren(remaining[switch_m.end() - 1:], ')')
404 body, expr = self._separate_at_paren(remaining, '}')
405 body = 'switch(%s){%s}' % (switch_val, body)
406 else:
407 body, expr = remaining, ''
408 start, cndn, increment = self._separate(constructor, ';')
409 self.interpret_expression(start, local_vars, allow_recursion)
410 while True:
411 if not _ternary(self.interpret_expression(cndn, local_vars, allow_recursion)):
412 break
413 try:
414 ret, should_abort = self.interpret_statement(body, local_vars, allow_recursion)
415 if should_abort:
416 return ret, True
417 except JS_Break:
418 break
419 except JS_Continue:
420 pass
421 self.interpret_expression(increment, local_vars, allow_recursion)
422 ret, should_abort = self.interpret_statement(expr, local_vars, allow_recursion)
423 return ret, should_abort or should_return
424
425 elif md.get('switch'):
426 switch_val, remaining = self._separate_at_paren(expr[m.end() - 1:], ')')
427 switch_val = self.interpret_expression(switch_val, local_vars, allow_recursion)
428 body, expr = self._separate_at_paren(remaining, '}')
429 items = body.replace('default:', 'case default:').split('case ')[1:]
430 for default in (False, True):
431 matched = False
432 for item in items:
433 case, stmt = (i.strip() for i in self._separate(item, ':', 1))
434 if default:
435 matched = matched or case == 'default'
436 elif not matched:
437 matched = (case != 'default'
438 and switch_val == self.interpret_expression(case, local_vars, allow_recursion))
439 if not matched:
440 continue
441 try:
442 ret, should_abort = self.interpret_statement(stmt, local_vars, allow_recursion)
443 if should_abort:
444 return ret
445 except JS_Break:
446 break
447 if matched:
448 break
449 ret, should_abort = self.interpret_statement(expr, local_vars, allow_recursion)
450 return ret, should_abort or should_return
451
452 # Comma separated statements
453 sub_expressions = list(self._separate(expr))
454 if len(sub_expressions) > 1:
455 for sub_expr in sub_expressions:
456 ret, should_abort = self.interpret_statement(sub_expr, local_vars, allow_recursion)
457 if should_abort:
458 return ret, True
459 return ret, False
460
461 for m in re.finditer(r'''(?x)
462 (?P<pre_sign>\+\+|--)(?P<var1>{_NAME_RE})|
463 (?P<var2>{_NAME_RE})(?P<post_sign>\+\+|--)'''.format(**globals()), expr):
464 var = m.group('var1') or m.group('var2')
465 start, end = m.span()
466 sign = m.group('pre_sign') or m.group('post_sign')
467 ret = local_vars[var]
468 local_vars[var] += 1 if sign[0] == '+' else -1
469 if m.group('pre_sign'):
470 ret = local_vars[var]
471 expr = expr[:start] + self._dump(ret, local_vars) + expr[end:]
472
473 if not expr:
474 return None, should_return
475
476 m = re.match(r'''(?x)
477 (?P<assign>
478 (?P<out>{_NAME_RE})(?:\[(?P<index>[^\]]+?)\])?\s*
479 (?P<op>{_OPERATOR_RE})?
480 =(?!=)(?P<expr>.*)$
481 )|(?P<return>
482 (?!if|return|true|false|null|undefined)(?P<name>{_NAME_RE})$
483 )|(?P<indexing>
484 (?P<in>{_NAME_RE})\[(?P<idx>.+)\]$
485 )|(?P<attribute>
486 (?P<var>{_NAME_RE})(?:(?P<nullish>\?)?\.(?P<member>[^(]+)|\[(?P<member2>[^\]]+)\])\s*
487 )|(?P<function>
488 (?P<fname>{_NAME_RE})\((?P<args>.*)\)$
489 )'''.format(**globals()), expr)
490 md = m.groupdict() if m else {}
491 if md.get('assign'):
492 left_val = local_vars.get(m.group('out'))
493
494 if not m.group('index'):
495 local_vars[m.group('out')] = self._operator(
496 m.group('op'), left_val, m.group('expr'), expr, local_vars, allow_recursion)
497 return local_vars[m.group('out')], should_return
498 elif left_val in (None, self.undefined):
499 raise self.Exception('Cannot index undefined variable ' + m.group('out'), expr=expr)
500
501 idx = self.interpret_expression(m.group('index'), local_vars, allow_recursion)
502 if not isinstance(idx, (int, float)):
503 raise self.Exception('List index %s must be integer' % (idx, ), expr=expr)
504 idx = int(idx)
505 left_val[idx] = self._operator(
506 m.group('op'), left_val[idx], m.group('expr'), expr, local_vars, allow_recursion)
507 return left_val[idx], should_return
508
509 elif expr.isdigit():
510 return int(expr), should_return
511
512 elif expr == 'break':
513 raise JS_Break()
514 elif expr == 'continue':
515 raise JS_Continue()
516
517 elif expr == 'undefined':
518 return self.undefined, should_return
519
520 elif md.get('return'):
521 return local_vars[m.group('name')], should_return
522
523 try:
524 ret = json.loads(js_to_json(expr)) # strict=True)
525 if not md.get('attribute'):
526 return ret, should_return
527 except ValueError:
528 pass
529
530 if md.get('indexing'):
531 val = local_vars[m.group('in')]
532 idx = self.interpret_expression(m.group('idx'), local_vars, allow_recursion)
533 return self._index(val, idx), should_return
534
535 for op, _ in self._all_operators():
536 # hackety: </> have higher priority than <</>>, but don't confuse them
537 skip_delim = (op + op) if op in '<>*?' else None
538 if op == '?':
539 skip_delim = (skip_delim, '?.')
540 separated = list(self._separate(expr, op, skip_delims=skip_delim))
541 if len(separated) < 2:
542 continue
543
544 right_expr = separated.pop()
545 while op == '-' and len(separated) > 1 and not separated[-1].strip():
546 right_expr = '-' + right_expr
547 separated.pop()
548 left_val = self.interpret_expression(op.join(separated), local_vars, allow_recursion)
549 return self._operator(op, left_val, right_expr, expr, local_vars, allow_recursion), should_return
550
551 if md.get('attribute'):
552 variable, member, nullish = m.group('var', 'member', 'nullish')
553 if not member:
554 member = self.interpret_expression(m.group('member2'), local_vars, allow_recursion)
555 arg_str = expr[m.end():]
556 if arg_str.startswith('('):
557 arg_str, remaining = self._separate_at_paren(arg_str, ')')
558 else:
559 arg_str, remaining = None, arg_str
560
561 def assertion(cndn, msg):
562 """ assert, but without risk of getting optimized out """
563 if not cndn:
564 raise ExtractorError('{member} {msg}'.format(**locals()), expr=expr)
565
566 def eval_method():
567 if (variable, member) == ('console', 'debug'):
568 return
569 types = {
570 'String': compat_str,
571 'Math': float,
572 }
573 obj = local_vars.get(variable)
574 if obj in (self.undefined, None):
575 obj = types.get(variable, self.undefined)
576 if obj is self.undefined:
577 try:
578 if variable not in self._objects:
579 self._objects[variable] = self.extract_object(variable)
580 obj = self._objects[variable]
581 except self.Exception:
582 if not nullish:
583 raise
584
585 if nullish and obj is self.undefined:
586 return self.undefined
587
588 # Member access
589 if arg_str is None:
590 return self._index(obj, member, nullish)
591
592 # Function call
593 argvals = [
594 self.interpret_expression(v, local_vars, allow_recursion)
595 for v in self._separate(arg_str)]
596
597 if obj == compat_str:
598 if member == 'fromCharCode':
599 assertion(argvals, 'takes one or more arguments')
600 return ''.join(map(chr, argvals))
601 raise self.Exception('Unsupported string method ' + member, expr=expr)
602 elif obj == float:
603 if member == 'pow':
604 assertion(len(argvals) == 2, 'takes two arguments')
605 return argvals[0] ** argvals[1]
606 raise self.Exception('Unsupported Math method ' + member, expr=expr)
607
608 if member == 'split':
609 assertion(argvals, 'takes one or more arguments')
610 assertion(len(argvals) == 1, 'with limit argument is not implemented')
611 return obj.split(argvals[0]) if argvals[0] else list(obj)
612 elif member == 'join':
613 assertion(isinstance(obj, list), 'must be applied on a list')
614 assertion(len(argvals) == 1, 'takes exactly one argument')
615 return argvals[0].join(obj)
616 elif member == 'reverse':
617 assertion(not argvals, 'does not take any arguments')
618 obj.reverse()
619 return obj
620 elif member == 'slice':
621 assertion(isinstance(obj, list), 'must be applied on a list')
622 assertion(len(argvals) == 1, 'takes exactly one argument')
623 return obj[argvals[0]:]
624 elif member == 'splice':
625 assertion(isinstance(obj, list), 'must be applied on a list')
626 assertion(argvals, 'takes one or more arguments')
627 index, howMany = map(int, (argvals + [len(obj)])[:2])
628 if index < 0:
629 index += len(obj)
630 add_items = argvals[2:]
631 res = []
632 for i in range(index, min(index + howMany, len(obj))):
633 res.append(obj.pop(index))
634 for i, item in enumerate(add_items):
635 obj.insert(index + i, item)
636 return res
637 elif member == 'unshift':
638 assertion(isinstance(obj, list), 'must be applied on a list')
639 assertion(argvals, 'takes one or more arguments')
640 for item in reversed(argvals):
641 obj.insert(0, item)
642 return obj
643 elif member == 'pop':
644 assertion(isinstance(obj, list), 'must be applied on a list')
645 assertion(not argvals, 'does not take any arguments')
646 if not obj:
647 return
648 return obj.pop()
649 elif member == 'push':
650 assertion(argvals, 'takes one or more arguments')
651 obj.extend(argvals)
652 return obj
653 elif member == 'forEach':
654 assertion(argvals, 'takes one or more arguments')
655 assertion(len(argvals) <= 2, 'takes at-most 2 arguments')
656 f, this = (argvals + [''])[:2]
657 return [f((item, idx, obj), {'this': this}, allow_recursion) for idx, item in enumerate(obj)]
658 elif member == 'indexOf':
659 assertion(argvals, 'takes one or more arguments')
660 assertion(len(argvals) <= 2, 'takes at-most 2 arguments')
661 idx, start = (argvals + [0])[:2]
662 try:
663 return obj.index(idx, start)
664 except ValueError:
665 return -1
666
667 idx = int(member) if isinstance(obj, list) else member
668 return obj[idx](argvals, allow_recursion=allow_recursion)
669
670 if remaining:
671 ret, should_abort = self.interpret_statement(
672 self._named_object(local_vars, eval_method()) + remaining,
673 local_vars, allow_recursion)
674 return ret, should_return or should_abort
675 else:
676 return eval_method(), should_return
677
678 elif md.get('function'):
679 fname = m.group('fname')
680 argvals = [self.interpret_expression(v, local_vars, allow_recursion)
681 for v in self._separate(m.group('args'))]
682 if fname in local_vars:
683 return local_vars[fname](argvals, allow_recursion=allow_recursion), should_return
684 elif fname not in self._functions:
685 self._functions[fname] = self.extract_function(fname)
686 return self._functions[fname](argvals, allow_recursion=allow_recursion), should_return
687
688 raise self.Exception(
689 'Unsupported JS expression ' + (expr[:40] if expr != stmt else ''), expr=stmt)
690
691 def interpret_expression(self, expr, local_vars, allow_recursion):
692 ret, should_return = self.interpret_statement(expr, local_vars, allow_recursion)
693 if should_return:
694 raise self.Exception('Cannot return from an expression', expr)
695 return ret
696
697 def extract_object(self, objname):
698 _FUNC_NAME_RE = r'''(?:[a-zA-Z$0-9]+|"[a-zA-Z$0-9]+"|'[a-zA-Z$0-9]+')'''
699 obj = {}
700 obj_m = re.search(
701 r'''(?x)
702 (?<!this\.)%s\s*=\s*{\s*
703 (?P<fields>(%s\s*:\s*function\s*\(.*?\)\s*{.*?}(?:,\s*)?)*)
704 }\s*;
705 ''' % (re.escape(objname), _FUNC_NAME_RE),
706 self.code)
707 if not obj_m:
708 raise self.Exception('Could not find object ' + objname)
709 fields = obj_m.group('fields')
710 # Currently, it only supports function definitions
711 fields_m = re.finditer(
712 r'''(?x)
713 (?P<key>%s)\s*:\s*function\s*\((?P<args>(?:%s|,)*)\){(?P<code>[^}]+)}
714 ''' % (_FUNC_NAME_RE, _NAME_RE),
715 fields)
716 for f in fields_m:
717 argnames = self.build_arglist(f.group('args'))
718 obj[remove_quotes(f.group('key'))] = self.build_function(argnames, f.group('code'))
719
720 return obj
721
722 def extract_function_code(self, funcname):
723 """ @returns argnames, code """
724 func_m = re.search(
725 r'''(?xs)
726 (?:
727 function\s+%(name)s|
728 [{;,]\s*%(name)s\s*=\s*function|
729 (?:var|const|let)\s+%(name)s\s*=\s*function
730 )\s*
731 \((?P<args>[^)]*)\)\s*
732 (?P<code>{.+})''' % {'name': re.escape(funcname)},
733 self.code)
734 code, _ = self._separate_at_paren(func_m.group('code'), '}') # refine the match
735 if func_m is None:
736 raise self.Exception('Could not find JS function "{funcname}"'.format(**locals()))
737 return self.build_arglist(func_m.group('args')), code
738
739 def extract_function(self, funcname):
740 return self.extract_function_from_code(*self.extract_function_code(funcname))
741
742 def extract_function_from_code(self, argnames, code, *global_stack):
743 local_vars = {}
744 while True:
745 mobj = re.search(r'function\((?P<args>[^)]*)\)\s*{', code)
746 if mobj is None:
747 break
748 start, body_start = mobj.span()
749 body, remaining = self._separate_at_paren(code[body_start - 1:], '}')
750 name = self._named_object(
751 local_vars,
752 self.extract_function_from_code(
753 self.build_arglist(mobj.group('args')),
754 body, local_vars, *global_stack))
755 code = code[:start] + name + remaining
756 return self.build_function(argnames, code, local_vars, *global_stack)
757
758 def call_function(self, funcname, *args):
759 return self.extract_function(funcname)(args)
760
761 @classmethod
762 def build_arglist(cls, arg_text):
763 if not arg_text:
764 return []
765
766 def valid_arg(y):
767 y = y.strip()
768 if not y:
769 raise cls.Exception('Missing arg in "%s"' % (arg_text, ))
770 return y
771
772 return [valid_arg(x) for x in cls._separate(arg_text)]
773
774 def build_function(self, argnames, code, *global_stack):
775 global_stack = list(global_stack) or [{}]
776 argnames = tuple(argnames)
777
778 def resf(args, kwargs={}, allow_recursion=100):
779 global_stack[0].update(
780 zip_longest(argnames, args, fillvalue=None))
781 global_stack[0].update(kwargs)
782 var_stack = LocalNameSpace(*global_stack)
783 ret, should_abort = self.interpret_statement(code.replace('\n', ''), var_stack, allow_recursion - 1)
784 if should_abort:
785 return ret
786 return resf
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