[jsinterp] Bring on-par with youtube-dl

Code from: https://github.com/ytdl-org/youtube-dl/pull/31175, https://github.com/ytdl-org/youtube-dl/pull/31182

Authored by pukkandan, dirkf
pull/4705/head
pukkandan 1 month ago
parent 8a3da4c68c
commit be13a6e525
No known key found for this signature in database
GPG Key ID: 7EEE9E1E817D0A39
  1. 120
      test/test_jsinterp.py
  2. 216
      yt_dlp/jsinterp.py

@ -7,8 +7,10 @@ import unittest
sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
import math
import re
from yt_dlp.jsinterp import JSInterpreter
from yt_dlp.jsinterp import JS_Undefined, JSInterpreter
class TestJSInterpreter(unittest.TestCase):
@ -66,6 +68,9 @@ class TestJSInterpreter(unittest.TestCase):
jsi = JSInterpreter('function f(){return 0 && 1 || 2;}')
self.assertEqual(jsi.call_function('f'), 2)
jsi = JSInterpreter('function f(){return 0 ?? 42;}')
self.assertEqual(jsi.call_function('f'), 0)
def test_array_access(self):
jsi = JSInterpreter('function f(){var x = [1,2,3]; x[0] = 4; x[0] = 5; x[2.0] = 7; return x;}')
self.assertEqual(jsi.call_function('f'), [5, 2, 7])
@ -229,6 +234,119 @@ class TestJSInterpreter(unittest.TestCase):
''')
self.assertEqual(jsi.call_function('x')([]), 1)
def test_null(self):
jsi = JSInterpreter('''
function x() { return null; }
''')
self.assertEqual(jsi.call_function('x'), None)
jsi = JSInterpreter('''
function x() { return [null > 0, null < 0, null == 0, null === 0]; }
''')
self.assertEqual(jsi.call_function('x'), [False, False, False, False])
jsi = JSInterpreter('''
function x() { return [null >= 0, null <= 0]; }
''')
self.assertEqual(jsi.call_function('x'), [True, True])
def test_undefined(self):
jsi = JSInterpreter('''
function x() { return undefined === undefined; }
''')
self.assertEqual(jsi.call_function('x'), True)
jsi = JSInterpreter('''
function x() { return undefined; }
''')
self.assertEqual(jsi.call_function('x'), JS_Undefined)
jsi = JSInterpreter('''
function x() { let v; return v; }
''')
self.assertEqual(jsi.call_function('x'), JS_Undefined)
jsi = JSInterpreter('''
function x() { return [undefined === undefined, undefined == undefined, undefined < undefined, undefined > undefined]; }
''')
self.assertEqual(jsi.call_function('x'), [True, True, False, False])
jsi = JSInterpreter('''
function x() { return [undefined === 0, undefined == 0, undefined < 0, undefined > 0]; }
''')
self.assertEqual(jsi.call_function('x'), [False, False, False, False])
jsi = JSInterpreter('''
function x() { return [undefined >= 0, undefined <= 0]; }
''')
self.assertEqual(jsi.call_function('x'), [False, False])
jsi = JSInterpreter('''
function x() { return [undefined > null, undefined < null, undefined == null, undefined === null]; }
''')
self.assertEqual(jsi.call_function('x'), [False, False, True, False])
jsi = JSInterpreter('''
function x() { return [undefined === null, undefined == null, undefined < null, undefined > null]; }
''')
self.assertEqual(jsi.call_function('x'), [False, True, False, False])
jsi = JSInterpreter('''
function x() { let v; return [42+v, v+42, v**42, 42**v, 0**v]; }
''')
for y in jsi.call_function('x'):
self.assertTrue(math.isnan(y))
jsi = JSInterpreter('''
function x() { let v; return v**0; }
''')
self.assertEqual(jsi.call_function('x'), 1)
jsi = JSInterpreter('''
function x() { let v; return [v>42, v<=42, v&&42, 42&&v]; }
''')
self.assertEqual(jsi.call_function('x'), [False, False, JS_Undefined, JS_Undefined])
jsi = JSInterpreter('function x(){return undefined ?? 42; }')
self.assertEqual(jsi.call_function('x'), 42)
def test_object(self):
jsi = JSInterpreter('''
function x() { return {}; }
''')
self.assertEqual(jsi.call_function('x'), {})
jsi = JSInterpreter('''
function x() { let a = {m1: 42, m2: 0 }; return [a["m1"], a.m2]; }
''')
self.assertEqual(jsi.call_function('x'), [42, 0])
jsi = JSInterpreter('''
function x() { let a; return a?.qq; }
''')
self.assertEqual(jsi.call_function('x'), JS_Undefined)
jsi = JSInterpreter('''
function x() { let a = {m1: 42, m2: 0 }; return a?.qq; }
''')
self.assertEqual(jsi.call_function('x'), JS_Undefined)
def test_regex(self):
jsi = JSInterpreter('''
function x() { let a=/,,[/,913,/](,)}/; }
''')
self.assertEqual(jsi.call_function('x'), None)
jsi = JSInterpreter('''
function x() { let a=/,,[/,913,/](,)}/; return a; }
''')
self.assertIsInstance(jsi.call_function('x'), re.Pattern)
jsi = JSInterpreter('''
function x() { let a=/,,[/,913,/](,)}/i; return a; }
''')
self.assertEqual(jsi.call_function('x').flags & re.I, re.I)
if __name__ == '__main__':
unittest.main()

@ -16,55 +16,118 @@ from .utils import (
write_string,
)
_NAME_RE = r'[a-zA-Z_$][\w$]*'
def _js_bit_op(op):
def wrapped(a, b):
def zeroise(x):
return 0 if x in (None, JS_Undefined) else x
return op(zeroise(a), zeroise(b))
return wrapped
def _js_arith_op(op):
def wrapped(a, b):
if JS_Undefined in (a, b):
return float('nan')
return op(a or 0, b or 0)
return wrapped
def _js_div(a, b):
if JS_Undefined in (a, b) or not (a and b):
return float('nan')
return (a or 0) / b if b else float('inf')
def _js_mod(a, b):
if JS_Undefined in (a, b) or not b:
return float('nan')
return (a or 0) % b
def _js_exp(a, b):
if not b:
return 1 # even 0 ** 0 !!
elif JS_Undefined in (a, b):
return float('nan')
return (a or 0) ** b
def _js_eq_op(op):
def wrapped(a, b):
if {a, b} <= {None, JS_Undefined}:
return op(a, a)
return op(a, b)
return wrapped
def _js_comp_op(op):
def wrapped(a, b):
if JS_Undefined in (a, b):
return False
return op(a or 0, b or 0)
return wrapped
def _js_ternary(cndn, if_true=True, if_false=False):
"""Simulate JS's ternary operator (cndn?if_true:if_false)"""
if cndn in (False, None, 0, '', JS_Undefined):
return if_false
with contextlib.suppress(TypeError):
if math.isnan(cndn): # NB: NaN cannot be checked by membership
return if_false
return if_true
# Ref: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Operator_Precedence
_OPERATORS = { # None => Defined in JSInterpreter._operator
'?': None,
'??': None,
'||': None,
'&&': None,
'&': lambda a, b: (a or 0) & (b or 0),
'|': lambda a, b: (a or 0) | (b or 0),
'^': lambda a, b: (a or 0) ^ (b or 0),
'|': _js_bit_op(operator.or_),
'^': _js_bit_op(operator.xor),
'&': _js_bit_op(operator.and_),
'===': operator.is_,
'==': _js_eq_op(operator.eq),
'!==': operator.is_not,
'==': operator.eq,
'!=': operator.ne,
'!=': _js_eq_op(operator.ne),
'<=': lambda a, b: (a or 0) <= (b or 0),
'>=': lambda a, b: (a or 0) >= (b or 0),
'<': lambda a, b: (a or 0) < (b or 0),
'>': lambda a, b: (a or 0) > (b or 0),
'<=': _js_comp_op(operator.le),
'>=': _js_comp_op(operator.ge),
'<': _js_comp_op(operator.lt),
'>': _js_comp_op(operator.gt),
'>>': operator.rshift,
'<<': operator.lshift,
'>>': _js_bit_op(operator.rshift),
'<<': _js_bit_op(operator.lshift),
'+': lambda a, b: (a or 0) + (b or 0),
'-': lambda a, b: (a or 0) - (b or 0),
'+': _js_arith_op(operator.add),
'-': _js_arith_op(operator.sub),
'*': lambda a, b: (a or 0) * (b or 0),
'/': lambda a, b: (a or 0) / b if b else float('NaN'),
'%': lambda a, b: (a or 0) % b if b else float('NaN'),
'**': operator.pow,
'*': _js_arith_op(operator.mul),
'/': _js_div,
'%': _js_mod,
'**': _js_exp,
}
_COMP_OPERATORS = {'===', '!==', '==', '!=', '<=', '>=', '<', '>'}
_MATCHING_PARENS = dict(zip('({[', ')}]'))
_NAME_RE = r'[a-zA-Z_$][\w$]*'
_MATCHING_PARENS = dict(zip(*zip('()', '{}', '[]')))
_QUOTES = '\'"/'
def _ternary(cndn, if_true=True, if_false=False):
"""Simulate JS's ternary operator (cndn?if_true:if_false)"""
if cndn in (False, None, 0, ''):
return if_false
with contextlib.suppress(TypeError):
if math.isnan(cndn): # NB: NaN cannot be checked by membership
return if_false
return if_true
class JS_Undefined:
pass
class JS_Break(ExtractorError):
@ -119,6 +182,21 @@ class Debugger:
class JSInterpreter:
__named_object_counter = 0
_RE_FLAGS = {
# special knowledge: Python's re flags are bitmask values, current max 128
# invent new bitmask values well above that for literal parsing
# TODO: new pattern class to execute matches with these flags
'd': 1024, # Generate indices for substring matches
'g': 2048, # Global search
'i': re.I, # Case-insensitive search
'm': re.M, # Multi-line search
's': re.S, # Allows . to match newline characters
'u': re.U, # Treat a pattern as a sequence of unicode code points
'y': 4096, # Perform a "sticky" search that matches starting at the current position in the target string
}
_EXC_NAME = '__yt_dlp_exception__'
def __init__(self, code, objects=None):
self.code, self._functions = code, {}
self._objects = {} if objects is None else objects
@ -135,6 +213,17 @@ class JSInterpreter:
namespace[name] = obj
return name
@classmethod
def _regex_flags(cls, expr):
flags = 0
if not expr:
return flags, expr
for idx, ch in enumerate(expr):
if ch not in cls._RE_FLAGS:
break
flags |= cls._RE_FLAGS[ch]
return flags, expr[idx + 1:]
@staticmethod
def _separate(expr, delim=',', max_split=None):
OP_CHARS = '+-*/%&|^=<>!,;'
@ -178,10 +267,13 @@ class JSInterpreter:
def _operator(self, op, left_val, right_expr, expr, local_vars, allow_recursion):
if op in ('||', '&&'):
if (op == '&&') ^ _ternary(left_val):
if (op == '&&') ^ _js_ternary(left_val):
return left_val # short circuiting
elif op == '??':
if left_val not in (None, JS_Undefined):
return left_val
elif op == '?':
right_expr = _ternary(left_val, *self._separate(right_expr, ':', 1))
right_expr = _js_ternary(left_val, *self._separate(right_expr, ':', 1))
right_val = self.interpret_expression(right_expr, local_vars, allow_recursion)
if not _OPERATORS.get(op):
@ -192,12 +284,14 @@ class JSInterpreter:
except Exception as e:
raise self.Exception(f'Failed to evaluate {left_val!r} {op} {right_val!r}', expr, cause=e)
def _index(self, obj, idx):
def _index(self, obj, idx, allow_undefined=False):
if idx == 'length':
return len(obj)
try:
return obj[int(idx)] if isinstance(obj, list) else obj[idx]
except Exception as e:
if allow_undefined:
return JS_Undefined
raise self.Exception(f'Cannot get index {idx}', repr(obj), cause=e)
def _dump(self, obj, namespace):
@ -233,8 +327,8 @@ class JSInterpreter:
if expr[0] in _QUOTES:
inner, outer = self._separate(expr, expr[0], 1)
if expr[0] == '/':
inner = inner[1:].replace('"', R'\"')
inner = re.compile(json.loads(js_to_json(f'"{inner}"', strict=True)))
flags, outer = self._regex_flags(outer)
inner = re.compile(inner[1:], flags=flags)
else:
inner = json.loads(js_to_json(f'{inner}{expr[0]}', strict=True))
if not outer:
@ -259,6 +353,17 @@ class JSInterpreter:
if expr.startswith('{'):
inner, outer = self._separate_at_paren(expr, '}')
# Look for Map first
sub_expressions = [list(self._separate(sub_expr.strip(), ':', 1)) for sub_expr in self._separate(inner)]
if all(len(sub_expr) == 2 for sub_expr in sub_expressions):
def dict_item(key, val):
val = self.interpret_expression(val, local_vars, allow_recursion)
if re.match(_NAME_RE, key):
return key, val
return self.interpret_expression(key, local_vars, allow_recursion), val
return dict(dict_item(k, v) for k, v in sub_expressions), should_return
inner, should_abort = self.interpret_statement(inner, local_vars, allow_recursion)
if not outer or should_abort:
return inner, should_abort or should_return
@ -295,17 +400,17 @@ class JSInterpreter:
if should_abort:
return ret, True
except JS_Throw as e:
local_vars['__ytdlp_exception__'] = e.error
local_vars[self._EXC_NAME] = e.error
except Exception as e:
# XXX: This works for now, but makes debugging future issues very hard
local_vars['__ytdlp_exception__'] = e
local_vars[self._EXC_NAME] = e
ret, should_abort = self.interpret_statement(expr, local_vars, allow_recursion)
return ret, should_abort or should_return
elif m and m.group('catch'):
catch_expr, expr = self._separate_at_paren(expr[m.end():], '}')
if '__ytdlp_exception__' in local_vars:
catch_vars = local_vars.new_child({m.group('err'): local_vars.pop('__ytdlp_exception__')})
if self._EXC_NAME in local_vars:
catch_vars = local_vars.new_child({m.group('err'): local_vars.pop(self._EXC_NAME)})
ret, should_abort = self.interpret_statement(catch_expr, catch_vars, allow_recursion)
if should_abort:
return ret, True
@ -328,7 +433,7 @@ class JSInterpreter:
start, cndn, increment = self._separate(constructor, ';')
self.interpret_expression(start, local_vars, allow_recursion)
while True:
if not _ternary(self.interpret_expression(cndn, local_vars, allow_recursion)):
if not _js_ternary(self.interpret_expression(cndn, local_vars, allow_recursion)):
break
try:
ret, should_abort = self.interpret_statement(body, local_vars, allow_recursion)
@ -397,13 +502,13 @@ class JSInterpreter:
(?P<assign>
(?P<out>{_NAME_RE})(?:\[(?P<index>[^\]]+?)\])?\s*
(?P<op>{"|".join(map(re.escape, set(_OPERATORS) - _COMP_OPERATORS))})?
=(?P<expr>.*)$
=(?!=)(?P<expr>.*)$
)|(?P<return>
(?!if|return|true|false|null|undefined)(?P<name>{_NAME_RE})$
)|(?P<indexing>
(?P<in>{_NAME_RE})\[(?P<idx>.+)\]$
)|(?P<attribute>
(?P<var>{_NAME_RE})(?:\.(?P<member>[^(]+)|\[(?P<member2>[^\]]+)\])\s*
(?P<var>{_NAME_RE})(?:(?P<nullish>\?)?\.(?P<member>[^(]+)|\[(?P<member2>[^\]]+)\])\s*
)|(?P<function>
(?P<fname>{_NAME_RE})\((?P<args>.*)\)$
)''', expr)
@ -414,7 +519,7 @@ class JSInterpreter:
local_vars[m.group('out')] = self._operator(
m.group('op'), left_val, m.group('expr'), expr, local_vars, allow_recursion)
return local_vars[m.group('out')], should_return
elif left_val is None:
elif left_val in (None, JS_Undefined):
raise self.Exception(f'Cannot index undefined variable {m.group("out")}', expr)
idx = self.interpret_expression(m.group('index'), local_vars, allow_recursion)
@ -432,9 +537,11 @@ class JSInterpreter:
raise JS_Break()
elif expr == 'continue':
raise JS_Continue()
elif expr == 'undefined':
return JS_Undefined, should_return
elif m and m.group('return'):
return local_vars[m.group('name')], should_return
return local_vars.get(m.group('name'), JS_Undefined), should_return
with contextlib.suppress(ValueError):
return json.loads(js_to_json(expr, strict=True)), should_return
@ -447,8 +554,11 @@ class JSInterpreter:
for op in _OPERATORS:
separated = list(self._separate(expr, op))
right_expr = separated.pop()
while op in '<>*-' and len(separated) > 1 and not separated[-1].strip():
separated.pop()
while True:
if op in '?<>*-' and len(separated) > 1 and not separated[-1].strip():
separated.pop()
elif not (separated and op == '?' and right_expr.startswith('.')):
break
right_expr = f'{op}{right_expr}'
if op != '-':
right_expr = f'{separated.pop()}{op}{right_expr}'
@ -458,8 +568,7 @@ class JSInterpreter:
return self._operator(op, left_val, right_expr, expr, local_vars, allow_recursion), should_return
if m and m.group('attribute'):
variable = m.group('var')
member = m.group('member')
variable, member, nullish = m.group('var', 'member', 'nullish')
if not member:
member = self.interpret_expression(m.group('member2'), local_vars, allow_recursion)
arg_str = expr[m.end():]
@ -486,12 +595,19 @@ class JSInterpreter:
obj = local_vars.get(variable, types.get(variable, NO_DEFAULT))
if obj is NO_DEFAULT:
if variable not in self._objects:
self._objects[variable] = self.extract_object(variable)
obj = self._objects[variable]
try:
self._objects[variable] = self.extract_object(variable)
except self.Exception:
if not nullish:
raise
obj = self._objects.get(variable, JS_Undefined)
if nullish and obj is JS_Undefined:
return JS_Undefined
# Member access
if arg_str is None:
return self._index(obj, member)
return self._index(obj, member, nullish)
# Function call
argvals = [

Loading…
Cancel
Save