mirror of
https://github.com/yt-dlp/yt-dlp.git
synced 2024-11-21 20:46:36 -05:00
540 lines
21 KiB
Python
540 lines
21 KiB
Python
from collections.abc import MutableMapping
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import json
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import operator
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import re
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from .utils import (
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ExtractorError,
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remove_quotes,
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)
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_OPERATORS = [
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('|', operator.or_),
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('^', operator.xor),
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('&', operator.and_),
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('>>', operator.rshift),
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('<<', operator.lshift),
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('-', operator.sub),
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('+', operator.add),
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('%', operator.mod),
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('/', operator.truediv),
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('*', operator.mul),
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]
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_ASSIGN_OPERATORS = [(op + '=', opfunc) for op, opfunc in _OPERATORS]
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_ASSIGN_OPERATORS.append(('=', (lambda cur, right: right)))
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_NAME_RE = r'[a-zA-Z_$][a-zA-Z_$0-9]*'
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class JS_Break(ExtractorError):
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def __init__(self):
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ExtractorError.__init__(self, 'Invalid break')
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class JS_Continue(ExtractorError):
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def __init__(self):
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ExtractorError.__init__(self, 'Invalid continue')
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class LocalNameSpace(MutableMapping):
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def __init__(self, *stack):
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self.stack = tuple(stack)
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def __getitem__(self, key):
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for scope in self.stack:
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if key in scope:
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return scope[key]
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raise KeyError(key)
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def __setitem__(self, key, value):
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for scope in self.stack:
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if key in scope:
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scope[key] = value
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break
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else:
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self.stack[0][key] = value
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return value
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def __delitem__(self, key):
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raise NotImplementedError('Deleting is not supported')
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def __iter__(self):
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for scope in self.stack:
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yield from scope
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def __len__(self, key):
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return len(iter(self))
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def __repr__(self):
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return f'LocalNameSpace{self.stack}'
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class JSInterpreter(object):
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def __init__(self, code, objects=None):
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if objects is None:
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objects = {}
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self.code = code
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self._functions = {}
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self._objects = objects
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self.__named_object_counter = 0
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def _named_object(self, namespace, obj):
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self.__named_object_counter += 1
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name = f'__yt_dlp_jsinterp_obj{self.__named_object_counter}'
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namespace[name] = obj
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return name
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@staticmethod
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def _seperate(expr, delim=',', max_split=None):
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if not expr:
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return
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parens = {'(': 0, '{': 0, '[': 0, ']': 0, '}': 0, ')': 0}
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start, splits, pos, max_pos = 0, 0, 0, len(delim) - 1
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for idx, char in enumerate(expr):
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if char in parens:
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parens[char] += 1
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is_in_parens = (parens['['] - parens[']']
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or parens['('] - parens[')']
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or parens['{'] - parens['}'])
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if char == delim[pos] and not is_in_parens:
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if pos == max_pos:
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pos = 0
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yield expr[start: idx - max_pos]
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start = idx + 1
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splits += 1
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if max_split and splits >= max_split:
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break
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else:
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pos += 1
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else:
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pos = 0
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yield expr[start:]
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@staticmethod
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def _seperate_at_paren(expr, delim):
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seperated = list(JSInterpreter._seperate(expr, delim, 1))
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if len(seperated) < 2:
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raise ExtractorError(f'No terminating paren {delim} in {expr}')
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return seperated[0][1:].strip(), seperated[1].strip()
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def interpret_statement(self, stmt, local_vars, allow_recursion=100):
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if allow_recursion < 0:
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raise ExtractorError('Recursion limit reached')
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sub_statements = list(self._seperate(stmt, ';'))
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stmt = (sub_statements or ['']).pop()
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for sub_stmt in sub_statements:
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ret, should_abort = self.interpret_statement(sub_stmt, local_vars, allow_recursion - 1)
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if should_abort:
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return ret
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should_abort = False
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stmt = stmt.lstrip()
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stmt_m = re.match(r'var\s', stmt)
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if stmt_m:
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expr = stmt[len(stmt_m.group(0)):]
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else:
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return_m = re.match(r'return(?:\s+|$)', stmt)
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if return_m:
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expr = stmt[len(return_m.group(0)):]
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should_abort = True
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else:
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# Try interpreting it as an expression
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expr = stmt
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v = self.interpret_expression(expr, local_vars, allow_recursion)
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return v, should_abort
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def interpret_expression(self, expr, local_vars, allow_recursion):
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expr = expr.strip()
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if expr == '': # Empty expression
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return None
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if expr.startswith('{'):
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inner, outer = self._seperate_at_paren(expr, '}')
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inner, should_abort = self.interpret_statement(inner, local_vars, allow_recursion - 1)
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if not outer or should_abort:
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return inner
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else:
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expr = json.dumps(inner) + outer
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if expr.startswith('('):
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inner, outer = self._seperate_at_paren(expr, ')')
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inner = self.interpret_expression(inner, local_vars, allow_recursion)
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if not outer:
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return inner
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else:
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expr = json.dumps(inner) + outer
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if expr.startswith('['):
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inner, outer = self._seperate_at_paren(expr, ']')
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name = self._named_object(local_vars, [
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self.interpret_expression(item, local_vars, allow_recursion)
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for item in self._seperate(inner)])
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expr = name + outer
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m = re.match(r'try\s*', expr)
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if m:
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if expr[m.end()] == '{':
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try_expr, expr = self._seperate_at_paren(expr[m.end():], '}')
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else:
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try_expr, expr = expr[m.end() - 1:], ''
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ret, should_abort = self.interpret_statement(try_expr, local_vars, allow_recursion - 1)
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if should_abort:
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return ret
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return self.interpret_statement(expr, local_vars, allow_recursion - 1)[0]
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m = re.match(r'catch\s*\(', expr)
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if m:
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# We ignore the catch block
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_, expr = self._seperate_at_paren(expr, '}')
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return self.interpret_statement(expr, local_vars, allow_recursion - 1)[0]
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m = re.match(r'for\s*\(', expr)
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if m:
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constructor, remaining = self._seperate_at_paren(expr[m.end() - 1:], ')')
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if remaining.startswith('{'):
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body, expr = self._seperate_at_paren(remaining, '}')
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else:
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m = re.match(r'switch\s*\(', remaining) # FIXME
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if m:
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switch_val, remaining = self._seperate_at_paren(remaining[m.end() - 1:], ')')
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body, expr = self._seperate_at_paren(remaining, '}')
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body = 'switch(%s){%s}' % (switch_val, body)
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else:
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body, expr = remaining, ''
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start, cndn, increment = self._seperate(constructor, ';')
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if self.interpret_statement(start, local_vars, allow_recursion - 1)[1]:
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raise ExtractorError(
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f'Premature return in the initialization of a for loop in {constructor!r}')
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while True:
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if not self.interpret_expression(cndn, local_vars, allow_recursion):
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break
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try:
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ret, should_abort = self.interpret_statement(body, local_vars, allow_recursion - 1)
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if should_abort:
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return ret
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except JS_Break:
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break
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except JS_Continue:
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pass
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if self.interpret_statement(increment, local_vars, allow_recursion - 1)[1]:
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raise ExtractorError(
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f'Premature return in the initialization of a for loop in {constructor!r}')
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return self.interpret_statement(expr, local_vars, allow_recursion - 1)[0]
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m = re.match(r'switch\s*\(', expr)
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if m:
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switch_val, remaining = self._seperate_at_paren(expr[m.end() - 1:], ')')
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switch_val = self.interpret_expression(switch_val, local_vars, allow_recursion)
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body, expr = self._seperate_at_paren(remaining, '}')
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items = body.replace('default:', 'case default:').split('case ')[1:]
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for default in (False, True):
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matched = False
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for item in items:
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case, stmt = [i.strip() for i in self._seperate(item, ':', 1)]
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if default:
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matched = matched or case == 'default'
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elif not matched:
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matched = case != 'default' and switch_val == self.interpret_expression(case, local_vars, allow_recursion)
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if not matched:
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continue
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try:
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ret, should_abort = self.interpret_statement(stmt, local_vars, allow_recursion - 1)
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if should_abort:
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return ret
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except JS_Break:
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break
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if matched:
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break
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return self.interpret_statement(expr, local_vars, allow_recursion - 1)[0]
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# Comma seperated statements
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sub_expressions = list(self._seperate(expr))
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expr = sub_expressions.pop().strip() if sub_expressions else ''
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for sub_expr in sub_expressions:
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self.interpret_expression(sub_expr, local_vars, allow_recursion)
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for m in re.finditer(rf'''(?x)
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(?P<pre_sign>\+\+|--)(?P<var1>{_NAME_RE})|
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(?P<var2>{_NAME_RE})(?P<post_sign>\+\+|--)''', expr):
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var = m.group('var1') or m.group('var2')
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start, end = m.span()
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sign = m.group('pre_sign') or m.group('post_sign')
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ret = local_vars[var]
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local_vars[var] += 1 if sign[0] == '+' else -1
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if m.group('pre_sign'):
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ret = local_vars[var]
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expr = expr[:start] + json.dumps(ret) + expr[end:]
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for op, opfunc in _ASSIGN_OPERATORS:
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m = re.match(r'''(?x)
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(?P<out>%s)(?:\[(?P<index>[^\]]+?)\])?
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\s*%s
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(?P<expr>.*)$''' % (_NAME_RE, re.escape(op)), expr)
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if not m:
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continue
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right_val = self.interpret_expression(m.group('expr'), local_vars, allow_recursion)
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if m.groupdict().get('index'):
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lvar = local_vars[m.group('out')]
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idx = self.interpret_expression(m.group('index'), local_vars, allow_recursion)
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if not isinstance(idx, int):
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raise ExtractorError(f'List indices must be integers: {idx}')
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cur = lvar[idx]
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val = opfunc(cur, right_val)
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lvar[idx] = val
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return val
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else:
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cur = local_vars.get(m.group('out'))
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val = opfunc(cur, right_val)
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local_vars[m.group('out')] = val
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return val
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if expr.isdigit():
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return int(expr)
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if expr == 'break':
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raise JS_Break()
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elif expr == 'continue':
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raise JS_Continue()
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var_m = re.match(
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r'(?!if|return|true|false|null)(?P<name>%s)$' % _NAME_RE,
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expr)
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if var_m:
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return local_vars[var_m.group('name')]
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try:
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return json.loads(expr)
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except ValueError:
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pass
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m = re.match(
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r'(?P<in>%s)\[(?P<idx>.+)\]$' % _NAME_RE, expr)
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if m:
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val = local_vars[m.group('in')]
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idx = self.interpret_expression(m.group('idx'), local_vars, allow_recursion)
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return val[idx]
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for op, opfunc in _OPERATORS:
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seperated = list(self._seperate(expr, op))
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if len(seperated) < 2:
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continue
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right_val = seperated.pop()
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left_val = op.join(seperated)
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left_val, should_abort = self.interpret_statement(
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left_val, local_vars, allow_recursion - 1)
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if should_abort:
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raise ExtractorError(f'Premature left-side return of {op} in {expr!r}')
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right_val, should_abort = self.interpret_statement(
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right_val, local_vars, allow_recursion - 1)
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if should_abort:
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raise ExtractorError(f'Premature right-side return of {op} in {expr!r}')
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return opfunc(left_val or 0, right_val)
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m = re.match(
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r'(?P<var>%s)(?:\.(?P<member>[^(]+)|\[(?P<member2>[^]]+)\])\s*' % _NAME_RE,
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expr)
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if m:
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variable = m.group('var')
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member = remove_quotes(m.group('member') or m.group('member2'))
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arg_str = expr[m.end():]
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if arg_str.startswith('('):
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arg_str, remaining = self._seperate_at_paren(arg_str, ')')
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else:
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arg_str, remaining = None, arg_str
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def assertion(cndn, msg):
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""" assert, but without risk of getting optimized out """
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if not cndn:
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raise ExtractorError(f'{member} {msg}: {expr}')
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def eval_method():
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nonlocal member
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if variable == 'String':
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obj = str
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elif variable in local_vars:
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obj = local_vars[variable]
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else:
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if variable not in self._objects:
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self._objects[variable] = self.extract_object(variable)
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obj = self._objects[variable]
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if arg_str is None:
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# Member access
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if member == 'length':
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return len(obj)
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return obj[member]
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# Function call
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argvals = [
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self.interpret_expression(v, local_vars, allow_recursion)
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for v in self._seperate(arg_str)]
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if obj == str:
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if member == 'fromCharCode':
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assertion(argvals, 'takes one or more arguments')
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return ''.join(map(chr, argvals))
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raise ExtractorError(f'Unsupported string method {member}')
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if member == 'split':
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assertion(argvals, 'takes one or more arguments')
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assertion(argvals == [''], 'with arguments is not implemented')
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return list(obj)
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elif member == 'join':
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assertion(isinstance(obj, list), 'must be applied on a list')
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assertion(len(argvals) == 1, 'takes exactly one argument')
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return argvals[0].join(obj)
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elif member == 'reverse':
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assertion(not argvals, 'does not take any arguments')
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obj.reverse()
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return obj
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elif member == 'slice':
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assertion(isinstance(obj, list), 'must be applied on a list')
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assertion(len(argvals) == 1, 'takes exactly one argument')
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return obj[argvals[0]:]
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elif member == 'splice':
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assertion(isinstance(obj, list), 'must be applied on a list')
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assertion(argvals, 'takes one or more arguments')
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index, howMany = map(int, (argvals + [len(obj)])[:2])
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if index < 0:
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index += len(obj)
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add_items = argvals[2:]
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res = []
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for i in range(index, min(index + howMany, len(obj))):
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res.append(obj.pop(index))
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for i, item in enumerate(add_items):
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obj.insert(index + i, item)
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return res
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elif member == 'unshift':
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assertion(isinstance(obj, list), 'must be applied on a list')
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assertion(argvals, 'takes one or more arguments')
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for item in reversed(argvals):
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obj.insert(0, item)
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return obj
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elif member == 'pop':
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assertion(isinstance(obj, list), 'must be applied on a list')
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assertion(not argvals, 'does not take any arguments')
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if not obj:
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return
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return obj.pop()
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elif member == 'push':
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assertion(argvals, 'takes one or more arguments')
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obj.extend(argvals)
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return obj
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elif member == 'forEach':
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assertion(argvals, 'takes one or more arguments')
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assertion(len(argvals) <= 2, 'takes at-most 2 arguments')
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f, this = (argvals + [''])[:2]
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return [f((item, idx, obj), this=this) for idx, item in enumerate(obj)]
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elif member == 'indexOf':
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assertion(argvals, 'takes one or more arguments')
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assertion(len(argvals) <= 2, 'takes at-most 2 arguments')
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idx, start = (argvals + [0])[:2]
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try:
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return obj.index(idx, start)
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except ValueError:
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return -1
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if isinstance(obj, list):
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member = int(member)
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return obj[member](argvals)
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if remaining:
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return self.interpret_expression(
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self._named_object(local_vars, eval_method()) + remaining,
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local_vars, allow_recursion)
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else:
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return eval_method()
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m = re.match(r'^(?P<func>%s)\((?P<args>[a-zA-Z0-9_$,]*)\)$' % _NAME_RE, expr)
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if m:
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fname = m.group('func')
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argvals = tuple([
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int(v) if v.isdigit() else local_vars[v]
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for v in self._seperate(m.group('args'))])
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if fname in local_vars:
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return local_vars[fname](argvals)
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elif fname not in self._functions:
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self._functions[fname] = self.extract_function(fname)
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return self._functions[fname](argvals)
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if expr:
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raise ExtractorError('Unsupported JS expression %r' % expr)
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def extract_object(self, objname):
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_FUNC_NAME_RE = r'''(?:[a-zA-Z$0-9]+|"[a-zA-Z$0-9]+"|'[a-zA-Z$0-9]+')'''
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obj = {}
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obj_m = re.search(
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r'''(?x)
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(?<!this\.)%s\s*=\s*{\s*
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(?P<fields>(%s\s*:\s*function\s*\(.*?\)\s*{.*?}(?:,\s*)?)*)
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}\s*;
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''' % (re.escape(objname), _FUNC_NAME_RE),
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self.code)
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fields = obj_m.group('fields')
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# Currently, it only supports function definitions
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fields_m = re.finditer(
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|
r'''(?x)
|
|
(?P<key>%s)\s*:\s*function\s*\((?P<args>[a-z,]+)\){(?P<code>[^}]+)}
|
|
''' % _FUNC_NAME_RE,
|
|
fields)
|
|
for f in fields_m:
|
|
argnames = f.group('args').split(',')
|
|
obj[remove_quotes(f.group('key'))] = self.build_function(argnames, f.group('code'))
|
|
|
|
return obj
|
|
|
|
def extract_function_code(self, funcname):
|
|
""" @returns argnames, code """
|
|
func_m = re.search(
|
|
r'''(?x)
|
|
(?:function\s+%s|[{;,]\s*%s\s*=\s*function|var\s+%s\s*=\s*function)\s*
|
|
\((?P<args>[^)]*)\)\s*
|
|
(?P<code>\{(?:(?!};)[^"]|"([^"]|\\")*")+\})''' % (
|
|
re.escape(funcname), re.escape(funcname), re.escape(funcname)),
|
|
self.code)
|
|
code, _ = self._seperate_at_paren(func_m.group('code'), '}') # refine the match
|
|
if func_m is None:
|
|
raise ExtractorError('Could not find JS function %r' % funcname)
|
|
return func_m.group('args').split(','), code
|
|
|
|
def extract_function(self, funcname):
|
|
return self.extract_function_from_code(*self.extract_function_code(funcname))
|
|
|
|
def extract_function_from_code(self, argnames, code, *global_stack):
|
|
local_vars = {}
|
|
while True:
|
|
mobj = re.search(r'function\((?P<args>[^)]*)\)\s*{', code)
|
|
if mobj is None:
|
|
break
|
|
start, body_start = mobj.span()
|
|
body, remaining = self._seperate_at_paren(code[body_start - 1:], '}')
|
|
name = self._named_object(
|
|
local_vars,
|
|
self.extract_function_from_code(
|
|
[str.strip(x) for x in mobj.group('args').split(',')],
|
|
body, local_vars, *global_stack))
|
|
code = code[:start] + name + remaining
|
|
return self.build_function(argnames, code, local_vars, *global_stack)
|
|
|
|
def call_function(self, funcname, *args):
|
|
return self.extract_function(funcname)(args)
|
|
|
|
def build_function(self, argnames, code, *global_stack):
|
|
global_stack = list(global_stack) or [{}]
|
|
local_vars = global_stack.pop(0)
|
|
|
|
def resf(args, **kwargs):
|
|
local_vars.update({
|
|
**dict(zip(argnames, args)),
|
|
**kwargs
|
|
})
|
|
var_stack = LocalNameSpace(local_vars, *global_stack)
|
|
for stmt in self._seperate(code.replace('\n', ''), ';'):
|
|
ret, should_abort = self.interpret_statement(stmt, var_stack)
|
|
if should_abort:
|
|
break
|
|
return ret
|
|
return resf
|