mirror of
https://github.com/ytdl-org/youtube-dl.git
synced 2024-11-15 03:27:46 +01:00
117 lines
4.1 KiB
Python
117 lines
4.1 KiB
Python
from __future__ import unicode_literals
|
|
|
|
import re
|
|
|
|
from .utils import (
|
|
ExtractorError,
|
|
)
|
|
|
|
|
|
class JSInterpreter(object):
|
|
def __init__(self, code):
|
|
self.code = code
|
|
self._functions = {}
|
|
|
|
def interpret_statement(self, stmt, local_vars, allow_recursion=20):
|
|
if allow_recursion < 0:
|
|
raise ExtractorError('Recursion limit reached')
|
|
|
|
if stmt.startswith('var '):
|
|
stmt = stmt[len('var '):]
|
|
ass_m = re.match(r'^(?P<out>[a-z]+)(?:\[(?P<index>[^\]]+)\])?' +
|
|
r'=(?P<expr>.*)$', stmt)
|
|
if ass_m:
|
|
if ass_m.groupdict().get('index'):
|
|
def assign(val):
|
|
lvar = local_vars[ass_m.group('out')]
|
|
idx = self.interpret_expression(
|
|
ass_m.group('index'), local_vars, allow_recursion)
|
|
assert isinstance(idx, int)
|
|
lvar[idx] = val
|
|
return val
|
|
expr = ass_m.group('expr')
|
|
else:
|
|
def assign(val):
|
|
local_vars[ass_m.group('out')] = val
|
|
return val
|
|
expr = ass_m.group('expr')
|
|
elif stmt.startswith('return '):
|
|
assign = lambda v: v
|
|
expr = stmt[len('return '):]
|
|
else:
|
|
raise ExtractorError(
|
|
'Cannot determine left side of statement in %r' % stmt)
|
|
|
|
v = self.interpret_expression(expr, local_vars, allow_recursion)
|
|
return assign(v)
|
|
|
|
def interpret_expression(self, expr, local_vars, allow_recursion):
|
|
if expr.isdigit():
|
|
return int(expr)
|
|
|
|
if expr.isalpha():
|
|
return local_vars[expr]
|
|
|
|
m = re.match(r'^(?P<in>[a-z]+)\.(?P<member>.*)$', expr)
|
|
if m:
|
|
member = m.group('member')
|
|
val = local_vars[m.group('in')]
|
|
if member == 'split("")':
|
|
return list(val)
|
|
if member == 'join("")':
|
|
return u''.join(val)
|
|
if member == 'length':
|
|
return len(val)
|
|
if member == 'reverse()':
|
|
return val[::-1]
|
|
slice_m = re.match(r'slice\((?P<idx>.*)\)', member)
|
|
if slice_m:
|
|
idx = self.interpret_expression(
|
|
slice_m.group('idx'), local_vars, allow_recursion - 1)
|
|
return val[idx:]
|
|
|
|
m = re.match(
|
|
r'^(?P<in>[a-z]+)\[(?P<idx>.+)\]$', expr)
|
|
if m:
|
|
val = local_vars[m.group('in')]
|
|
idx = self.interpret_expression(
|
|
m.group('idx'), local_vars, allow_recursion - 1)
|
|
return val[idx]
|
|
|
|
m = re.match(r'^(?P<a>.+?)(?P<op>[%])(?P<b>.+?)$', expr)
|
|
if m:
|
|
a = self.interpret_expression(
|
|
m.group('a'), local_vars, allow_recursion)
|
|
b = self.interpret_expression(
|
|
m.group('b'), local_vars, allow_recursion)
|
|
return a % b
|
|
|
|
m = re.match(
|
|
r'^(?P<func>[a-zA-Z$]+)\((?P<args>[a-z0-9,]+)\)$', expr)
|
|
if m:
|
|
fname = m.group('func')
|
|
if fname not in self._functions:
|
|
self._functions[fname] = self.extract_function(fname)
|
|
argvals = [int(v) if v.isdigit() else local_vars[v]
|
|
for v in m.group('args').split(',')]
|
|
return self._functions[fname](argvals)
|
|
raise ExtractorError('Unsupported JS expression %r' % expr)
|
|
|
|
def extract_function(self, funcname):
|
|
func_m = re.search(
|
|
(r'(?:function %s|%s\s*=\s*function)' % (
|
|
re.escape(funcname), re.escape(funcname))) +
|
|
r'\((?P<args>[a-z,]+)\){(?P<code>[^}]+)}',
|
|
self.code)
|
|
if func_m is None:
|
|
raise ExtractorError('Could not find JS function %r' % funcname)
|
|
argnames = func_m.group('args').split(',')
|
|
|
|
def resf(args):
|
|
local_vars = dict(zip(argnames, args))
|
|
for stmt in func_m.group('code').split(';'):
|
|
res = self.interpret_statement(stmt, local_vars)
|
|
return res
|
|
return resf
|
|
|