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Use reader instead of indexing

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This commit is contained in:
Philipp Hagemeister 2013-09-21 15:32:37 +02:00
parent 8379969834
commit ba552f542f
1 changed files with 118 additions and 136 deletions
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246
youtube_dl/extractor/youtube.py
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@ -590,16 +590,16 @@ def extract_tags(content):
for tag_code, tag in extract_tags(content) for tag_code, tag in extract_tags(content)
if tag_code == 82) if tag_code == 82)
p = code_tag.index(b'\0', 4) + 1 p = code_tag.index(b'\0', 4) + 1
code_reader = io.BytesIO(code_tag[p:])
# Parse ABC (AVM2 ByteCode) # Parse ABC (AVM2 ByteCode)
def read_int(data=None, pos=None): def read_int(reader=None):
if hasattr(data, 'read'): if reader is None:
assert pos is None reader = code_reader
res = 0 res = 0
shift = 0 shift = 0
for _ in range(5): for _ in range(5):
buf = data.read(1) buf = reader.read(1)
assert len(buf) == 1 assert len(buf) == 1
b = struct.unpack('<B', buf)[0] b = struct.unpack('<B', buf)[0]
res = res | ((b & 0x7f) << shift) res = res | ((b & 0x7f) << shift)
@ -608,81 +608,65 @@ def read_int(data=None, pos=None):
shift += 7 shift += 7
return res return res
if data is None: def u30(reader=None):
data = code_tag res = read_int(reader)
if pos is None:
pos = p
res = 0
shift = 0
for _ in range(5):
b = struct.unpack('<B', data[pos:pos+1])[0]
pos += 1
res = res | ((b & 0x7f) << shift)
if b & 0x80 == 0:
break
shift += 7
return (res, pos)
assert read_int(b'\x00', 0) == (0, 1)
assert read_int(b'\x10', 0) == (16, 1)
assert read_int(b'\x34', 0) == (0x34, 1)
assert read_int(b'\xb4\x12', 0) == (0x12 * 0x80 + 0x34, 2)
assert read_int(b'\xff\xff\xff\x00', 0) == (0x1fffff, 4)
def u30(*args, **kwargs):
res = read_int(*args, **kwargs)
if isinstance(res, tuple):
assert res[0] & 0xf0000000 == 0
else:
assert res & 0xf0000000 == 0 assert res & 0xf0000000 == 0
return res return res
u32 = read_int u32 = read_int
def s32(data=None, pos=None): def s32(reader=None):
v, pos = read_int(data, pos) v = read_int(reader)
if v & 0x80000000 != 0: if v & 0x80000000 != 0:
v = - ((v ^ 0xffffffff) + 1) v = - ((v ^ 0xffffffff) + 1)
return (v, pos) return v
assert s32(b'\xff\xff\xff\xff\x0f', 0) == (-1, 5)
def string(): def string(reader=None):
slen, p = u30() if reader is None:
return (code_tag[p:p+slen].decode('utf-8'), p + slen) reader = code_reader
slen = u30(reader)
resb = reader.read(slen)
assert len(resb) == slen
return resb.decode('utf-8')
def read_byte(data=None, pos=None): def read_bytes(count, reader=None):
if data is None: if reader is None:
data = code_tag reader = code_reader
if pos is None: resb = reader.read(count)
pos = p assert len(resb) == count
res = struct.unpack('<B', data[pos:pos+1])[0] return resb
return (res, pos + 1)
def read_byte(reader=None):
resb = read_bytes(1, reader=reader)
res = struct.unpack('<B', resb)[0]
return res
# minor_version + major_version # minor_version + major_version
p += 2 + 2 _ = read_bytes(4)
# Constant pool # Constant pool
int_count, p = u30() int_count = u30()
for _c in range(1, int_count): for _c in range(1, int_count):
_, p = s32() _ = s32()
uint_count, p = u30() uint_count = u30()
for _c in range(1, uint_count): for _c in range(1, uint_count):
_, p = u32() _ = u32()
double_count, p = u30() double_count = u30()
p += (double_count-1) * 8 _ = read_bytes((double_count-1) * 8)
string_count, p = u30() string_count = u30()
constant_strings = [u''] constant_strings = [u'']
for _c in range(1, string_count): for _c in range(1, string_count):
s, p = string() s = string()
constant_strings.append(s) constant_strings.append(s)
namespace_count, p = u30() namespace_count = u30()
for _c in range(1, namespace_count): for _c in range(1, namespace_count):
p += 1 # kind _ = read_bytes(1) # kind
_, p = u30() # name _ = u30() # name
ns_set_count, p = u30() ns_set_count = u30()
for _c in range(1, ns_set_count): for _c in range(1, ns_set_count):
count, p = u30() count = u30()
for _c2 in range(count): for _c2 in range(count):
_, p = u30() _ = u30()
multiname_count, p = u30() multiname_count = u30()
MULTINAME_SIZES = { MULTINAME_SIZES = {
0x07: 2, # QName 0x07: 2, # QName
0x0d: 2, # QNameA 0x0d: 2, # QNameA
@ -697,108 +681,106 @@ def read_byte(data=None, pos=None):
} }
multinames = [u''] multinames = [u'']
for _c in range(1, multiname_count): for _c in range(1, multiname_count):
kind, p = u30() kind = u30()
assert kind in MULTINAME_SIZES, u'Invalid multiname kind %r' % kind assert kind in MULTINAME_SIZES, u'Invalid multiname kind %r' % kind
if kind == 0x07: if kind == 0x07:
namespace_idx, p = u30() namespace_idx = u30()
name_idx, p = u30() name_idx = u30()
multinames.append(constant_strings[name_idx]) multinames.append(constant_strings[name_idx])
else: else:
multinames.append('[MULTINAME kind: %d]' % kind) multinames.append('[MULTINAME kind: %d]' % kind)
for _c2 in range(MULTINAME_SIZES[kind]): for _c2 in range(MULTINAME_SIZES[kind]):
_, p = u30() _ = u30()
# Methods # Methods
method_count, p = u30() method_count = u30()
MethodInfo = collections.namedtuple( MethodInfo = collections.namedtuple(
'MethodInfo', 'MethodInfo',
['NEED_ARGUMENTS', 'NEED_REST']) ['NEED_ARGUMENTS', 'NEED_REST'])
method_infos = [] method_infos = []
for method_id in range(method_count): for method_id in range(method_count):
param_count, p = u30() param_count = u30()
_, p = u30() # return type _ = u30() # return type
for _ in range(param_count): for _ in range(param_count):
_, p = u30() # param type _ = u30() # param type
_, p = u30() # name index (always 0 for youtube) _ = u30() # name index (always 0 for youtube)
flags, p = read_byte() flags = read_byte()
if flags & 0x08 != 0: if flags & 0x08 != 0:
# Options present # Options present
option_count, p = u30() option_count = u30()
for c in range(option_count): for c in range(option_count):
_, p = u30() # val _ = u30() # val
p += 1 # kind _ = read_bytes(1) # kind
if flags & 0x80 != 0: if flags & 0x80 != 0:
# Param names present # Param names present
for _ in range(param_count): for _ in range(param_count):
_, p = u30() # param name _ = u30() # param name
mi = MethodInfo(flags & 0x01 != 0, flags & 0x04 != 0) mi = MethodInfo(flags & 0x01 != 0, flags & 0x04 != 0)
method_infos.append(mi) method_infos.append(mi)
# Metadata # Metadata
metadata_count, p = u30() metadata_count = u30()
for _c in range(metadata_count): for _c in range(metadata_count):
_, p = u30() # name _ = u30() # name
item_count, p = u30() item_count = u30()
for _c2 in range(item_count): for _c2 in range(item_count):
_, p = u30() # key _ = u30() # key
_, p = u30() # value _ = u30() # value
def parse_traits_info(pos=None): def parse_traits_info():
if pos is None: trait_name_idx = u30()
pos = p kind_full = read_byte()
trait_name_idx, pos = u30(pos=pos)
kind_full, pos = read_byte(pos=pos)
kind = kind_full & 0x0f kind = kind_full & 0x0f
attrs = kind_full >> 4 attrs = kind_full >> 4
methods = {} methods = {}
if kind in [0x00, 0x06]: # Slot or Const if kind in [0x00, 0x06]: # Slot or Const
_, pos = u30(pos=pos) # Slot id _ = u30() # Slot id
type_name_idx, pos = u30(pos=pos) type_name_idx = u30()
vindex, pos = u30(pos=pos) vindex = u30()
if vindex != 0: if vindex != 0:
_, pos = read_byte(pos=pos) # vkind _ = read_byte() # vkind
elif kind in [0x01, 0x02, 0x03]: # Method / Getter / Setter elif kind in [0x01, 0x02, 0x03]: # Method / Getter / Setter
_, pos = u30(pos=pos) # disp_id _ = u30() # disp_id
method_idx, pos = u30(pos=pos) method_idx = u30()
methods[multinames[trait_name_idx]] = method_idx methods[multinames[trait_name_idx]] = method_idx
elif kind == 0x04: # Class elif kind == 0x04: # Class
_, pos = u30(pos=pos) # slot_id _ = u30() # slot_id
_, pos = u30(pos=pos) # classi _ = u30() # classi
elif kind == 0x05: # Function elif kind == 0x05: # Function
_, pos = u30(pos=pos) # slot_id _ = u30() # slot_id
function_idx, pos = u30(pos=pos) function_idx = u30()
methods[function_idx] = multinames[trait_name_idx] methods[function_idx] = multinames[trait_name_idx]
else: else:
raise ExtractorError(u'Unsupported trait kind %d' % kind) raise ExtractorError(u'Unsupported trait kind %d' % kind)
if attrs & 0x4 != 0: # Metadata present if attrs & 0x4 != 0: # Metadata present
metadata_count, pos = u30(pos=pos) metadata_count = u30()
for _c3 in range(metadata_count): for _c3 in range(metadata_count):
_, pos = u30(pos=pos) _ = u30()
return (methods, pos) return methods
# Classes # Classes
TARGET_CLASSNAME = u'SignatureDecipher' TARGET_CLASSNAME = u'SignatureDecipher'
searched_idx = multinames.index(TARGET_CLASSNAME) searched_idx = multinames.index(TARGET_CLASSNAME)
searched_class_id = None searched_class_id = None
class_count, p = u30() class_count = u30()
for class_id in range(class_count): for class_id in range(class_count):
name_idx, p = u30() name_idx = u30()
if name_idx == searched_idx: if name_idx == searched_idx:
# We found the class we're looking for! # We found the class we're looking for!
searched_class_id = class_id searched_class_id = class_id
_, p = u30() # super_name idx _ = u30() # super_name idx
flags, p = read_byte() flags = read_byte()
if flags & 0x08 != 0: # Protected namespace is present if flags & 0x08 != 0: # Protected namespace is present
protected_ns_idx, p = u30() protected_ns_idx = u30()
intrf_count, p = u30() intrf_count = u30()
for _c2 in range(intrf_count): for _c2 in range(intrf_count):
_, p = u30() _ = u30()
_, p = u30() # iinit _ = u30() # iinit
trait_count, p = u30() trait_count = u30()
for _c2 in range(trait_count): for _c2 in range(trait_count):
_, p = parse_traits_info() _ = parse_traits_info()
if searched_class_id is None: if searched_class_id is None:
raise ExtractorError(u'Target class %r not found' % raise ExtractorError(u'Target class %r not found' %
@ -807,10 +789,10 @@ def parse_traits_info(pos=None):
method_names = {} method_names = {}
method_idxs = {} method_idxs = {}
for class_id in range(class_count): for class_id in range(class_count):
_, p = u30() # cinit _ = u30() # cinit
trait_count, p = u30() trait_count = u30()
for _c2 in range(trait_count): for _c2 in range(trait_count):
trait_methods, p = parse_traits_info() trait_methods = parse_traits_info()
if class_id == searched_class_id: if class_id == searched_class_id:
method_names.update(trait_methods.items()) method_names.update(trait_methods.items())
method_idxs.update(dict( method_idxs.update(dict(
@ -818,40 +800,40 @@ def parse_traits_info(pos=None):
for name, idx in trait_methods.items())) for name, idx in trait_methods.items()))
# Scripts # Scripts
script_count, p = u30() script_count = u30()
for _c in range(script_count): for _c in range(script_count):
_, p = u30() # init _ = u30() # init
trait_count, p = u30() trait_count = u30()
for _c2 in range(trait_count): for _c2 in range(trait_count):
_, p = parse_traits_info() _ = parse_traits_info()
# Method bodies # Method bodies
method_body_count, p = u30() method_body_count = u30()
Method = collections.namedtuple('Method', ['code', 'local_count']) Method = collections.namedtuple('Method', ['code', 'local_count'])
methods = {} methods = {}
for _c in range(method_body_count): for _c in range(method_body_count):
method_idx, p = u30() method_idx = u30()
max_stack, p = u30() max_stack = u30()
local_count, p = u30() local_count = u30()
init_scope_depth, p = u30() init_scope_depth = u30()
max_scope_depth, p = u30() max_scope_depth = u30()
code_length, p = u30() code_length = u30()
code = read_bytes(code_length)
if method_idx in method_idxs: if method_idx in method_idxs:
m = Method(code_tag[p:p+code_length], local_count) m = Method(code, local_count)
methods[method_idxs[method_idx]] = m methods[method_idxs[method_idx]] = m
p += code_length exception_count = u30()
exception_count, p = u30()
for _c2 in range(exception_count): for _c2 in range(exception_count):
_, p = u30() # from _ = u30() # from
_, p = u30() # to _ = u30() # to
_, p = u30() # target _ = u30() # target
_, p = u30() # exc_type _ = u30() # exc_type
_, p = u30() # var_name _ = u30() # var_name
trait_count, p = u30() trait_count = u30()
for _c2 in range(trait_count): for _c2 in range(trait_count):
_, p = parse_traits_info() _ = parse_traits_info()
assert p == len(code_tag) assert p + code_reader.tell() == len(code_tag)
assert len(methods) == len(method_idxs) assert len(methods) == len(method_idxs)
method_pyfunctions = {} method_pyfunctions = {}