##// END OF EJS Templates
compression: only declare revlog support for available engine...
compression: only declare revlog support for available engine Even if we know that an engine support revlog compression, the Mercurial process still won't support it if the compression engine is not available.

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pybser.py
483 lines | 16.6 KiB | text/x-python | PythonLexer
# Copyright 2015 Facebook, Inc.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# * Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
#
# * Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
#
# * Neither the name Facebook nor the names of its contributors may be used to
# endorse or promote products derived from this software without specific
# prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
# no unicode literals
import binascii
import collections
import ctypes
import struct
import sys
from . import (
compat,
)
BSER_ARRAY = b'\x00'
BSER_OBJECT = b'\x01'
BSER_BYTESTRING = b'\x02'
BSER_INT8 = b'\x03'
BSER_INT16 = b'\x04'
BSER_INT32 = b'\x05'
BSER_INT64 = b'\x06'
BSER_REAL = b'\x07'
BSER_TRUE = b'\x08'
BSER_FALSE = b'\x09'
BSER_NULL = b'\x0a'
BSER_TEMPLATE = b'\x0b'
BSER_SKIP = b'\x0c'
BSER_UTF8STRING = b'\x0d'
if compat.PYTHON3:
STRING_TYPES = (str, bytes)
unicode = str
def tobytes(i):
return str(i).encode('ascii')
long = int
else:
STRING_TYPES = (unicode, str)
tobytes = bytes
# Leave room for the serialization header, which includes
# our overall length. To make things simpler, we'll use an
# int32 for the header
EMPTY_HEADER = b"\x00\x01\x05\x00\x00\x00\x00"
EMPTY_HEADER_V2 = b"\x00\x02\x00\x00\x00\x00\x05\x00\x00\x00\x00"
def _int_size(x):
"""Return the smallest size int that can store the value"""
if -0x80 <= x <= 0x7F:
return 1
elif -0x8000 <= x <= 0x7FFF:
return 2
elif -0x80000000 <= x <= 0x7FFFFFFF:
return 4
elif long(-0x8000000000000000) <= x <= long(0x7FFFFFFFFFFFFFFF):
return 8
else:
raise RuntimeError('Cannot represent value: ' + str(x))
def _buf_pos(buf, pos):
ret = buf[pos]
# In Python 2, buf is a str array so buf[pos] is a string. In Python 3, buf
# is a bytes array and buf[pos] is an integer.
if compat.PYTHON3:
ret = bytes((ret,))
return ret
class _bser_buffer(object):
def __init__(self, version):
self.bser_version = version
self.buf = ctypes.create_string_buffer(8192)
if self.bser_version == 1:
struct.pack_into(tobytes(len(EMPTY_HEADER)) + b's', self.buf, 0,
EMPTY_HEADER)
self.wpos = len(EMPTY_HEADER)
else:
assert self.bser_version == 2
struct.pack_into(tobytes(len(EMPTY_HEADER_V2)) + b's', self.buf, 0,
EMPTY_HEADER_V2)
self.wpos = len(EMPTY_HEADER_V2)
def ensure_size(self, size):
while ctypes.sizeof(self.buf) - self.wpos < size:
ctypes.resize(self.buf, ctypes.sizeof(self.buf) * 2)
def append_long(self, val):
size = _int_size(val)
to_write = size + 1
self.ensure_size(to_write)
if size == 1:
struct.pack_into(b'=cb', self.buf, self.wpos, BSER_INT8, val)
elif size == 2:
struct.pack_into(b'=ch', self.buf, self.wpos, BSER_INT16, val)
elif size == 4:
struct.pack_into(b'=ci', self.buf, self.wpos, BSER_INT32, val)
elif size == 8:
struct.pack_into(b'=cq', self.buf, self.wpos, BSER_INT64, val)
else:
raise RuntimeError('Cannot represent this long value')
self.wpos += to_write
def append_string(self, s):
if isinstance(s, unicode):
s = s.encode('utf-8')
s_len = len(s)
size = _int_size(s_len)
to_write = 2 + size + s_len
self.ensure_size(to_write)
if size == 1:
struct.pack_into(b'=ccb' + tobytes(s_len) + b's', self.buf,
self.wpos, BSER_BYTESTRING, BSER_INT8, s_len, s)
elif size == 2:
struct.pack_into(b'=cch' + tobytes(s_len) + b's', self.buf,
self.wpos, BSER_BYTESTRING, BSER_INT16, s_len, s)
elif size == 4:
struct.pack_into(b'=cci' + tobytes(s_len) + b's', self.buf,
self.wpos, BSER_BYTESTRING, BSER_INT32, s_len, s)
elif size == 8:
struct.pack_into(b'=ccq' + tobytes(s_len) + b's', self.buf,
self.wpos, BSER_BYTESTRING, BSER_INT64, s_len, s)
else:
raise RuntimeError('Cannot represent this string value')
self.wpos += to_write
def append_recursive(self, val):
if isinstance(val, bool):
needed = 1
self.ensure_size(needed)
if val:
to_encode = BSER_TRUE
else:
to_encode = BSER_FALSE
struct.pack_into(b'=c', self.buf, self.wpos, to_encode)
self.wpos += needed
elif val is None:
needed = 1
self.ensure_size(needed)
struct.pack_into(b'=c', self.buf, self.wpos, BSER_NULL)
self.wpos += needed
elif isinstance(val, (int, long)):
self.append_long(val)
elif isinstance(val, STRING_TYPES):
self.append_string(val)
elif isinstance(val, float):
needed = 9
self.ensure_size(needed)
struct.pack_into(b'=cd', self.buf, self.wpos, BSER_REAL, val)
self.wpos += needed
elif isinstance(val, collections.Mapping) and \
isinstance(val, collections.Sized):
val_len = len(val)
size = _int_size(val_len)
needed = 2 + size
self.ensure_size(needed)
if size == 1:
struct.pack_into(b'=ccb', self.buf, self.wpos, BSER_OBJECT,
BSER_INT8, val_len)
elif size == 2:
struct.pack_into(b'=cch', self.buf, self.wpos, BSER_OBJECT,
BSER_INT16, val_len)
elif size == 4:
struct.pack_into(b'=cci', self.buf, self.wpos, BSER_OBJECT,
BSER_INT32, val_len)
elif size == 8:
struct.pack_into(b'=ccq', self.buf, self.wpos, BSER_OBJECT,
BSER_INT64, val_len)
else:
raise RuntimeError('Cannot represent this mapping value')
self.wpos += needed
if compat.PYTHON3:
iteritems = val.items()
else:
iteritems = val.iteritems()
for k, v in iteritems:
self.append_string(k)
self.append_recursive(v)
elif isinstance(val, collections.Iterable) and \
isinstance(val, collections.Sized):
val_len = len(val)
size = _int_size(val_len)
needed = 2 + size
self.ensure_size(needed)
if size == 1:
struct.pack_into(b'=ccb', self.buf, self.wpos, BSER_ARRAY,
BSER_INT8, val_len)
elif size == 2:
struct.pack_into(b'=cch', self.buf, self.wpos, BSER_ARRAY,
BSER_INT16, val_len)
elif size == 4:
struct.pack_into(b'=cci', self.buf, self.wpos, BSER_ARRAY,
BSER_INT32, val_len)
elif size == 8:
struct.pack_into(b'=ccq', self.buf, self.wpos, BSER_ARRAY,
BSER_INT64, val_len)
else:
raise RuntimeError('Cannot represent this sequence value')
self.wpos += needed
for v in val:
self.append_recursive(v)
else:
raise RuntimeError('Cannot represent unknown value type')
def dumps(obj, version=1, capabilities=0):
bser_buf = _bser_buffer(version=version)
bser_buf.append_recursive(obj)
# Now fill in the overall length
if version == 1:
obj_len = bser_buf.wpos - len(EMPTY_HEADER)
struct.pack_into(b'=i', bser_buf.buf, 3, obj_len)
else:
obj_len = bser_buf.wpos - len(EMPTY_HEADER_V2)
struct.pack_into(b'=i', bser_buf.buf, 2, capabilities)
struct.pack_into(b'=i', bser_buf.buf, 7, obj_len)
return bser_buf.buf.raw[:bser_buf.wpos]
# This is a quack-alike with the bserObjectType in bser.c
# It provides by getattr accessors and getitem for both index
# and name.
class _BunserDict(object):
__slots__ = ('_keys', '_values')
def __init__(self, keys, values):
self._keys = keys
self._values = values
def __getattr__(self, name):
return self.__getitem__(name)
def __getitem__(self, key):
if isinstance(key, (int, long)):
return self._values[key]
elif key.startswith('st_'):
# hack^Wfeature to allow mercurial to use "st_size" to
# reference "size"
key = key[3:]
try:
return self._values[self._keys.index(key)]
except ValueError:
raise KeyError('_BunserDict has no key %s' % key)
def __len__(self):
return len(self._keys)
class Bunser(object):
def __init__(self, mutable=True, value_encoding=None, value_errors=None):
self.mutable = mutable
self.value_encoding = value_encoding
if value_encoding is None:
self.value_errors = None
elif value_errors is None:
self.value_errors = 'strict'
else:
self.value_errors = value_errors
@staticmethod
def unser_int(buf, pos):
try:
int_type = _buf_pos(buf, pos)
except IndexError:
raise ValueError('Invalid bser int encoding, pos out of range')
if int_type == BSER_INT8:
needed = 2
fmt = b'=b'
elif int_type == BSER_INT16:
needed = 3
fmt = b'=h'
elif int_type == BSER_INT32:
needed = 5
fmt = b'=i'
elif int_type == BSER_INT64:
needed = 9
fmt = b'=q'
else:
raise ValueError('Invalid bser int encoding 0x%s' %
binascii.hexlify(int_type).decode('ascii'))
int_val = struct.unpack_from(fmt, buf, pos + 1)[0]
return (int_val, pos + needed)
def unser_utf8_string(self, buf, pos):
str_len, pos = self.unser_int(buf, pos + 1)
str_val = struct.unpack_from(tobytes(str_len) + b's', buf, pos)[0]
return (str_val.decode('utf-8'), pos + str_len)
def unser_bytestring(self, buf, pos):
str_len, pos = self.unser_int(buf, pos + 1)
str_val = struct.unpack_from(tobytes(str_len) + b's', buf, pos)[0]
if self.value_encoding is not None:
str_val = str_val.decode(self.value_encoding, self.value_errors)
# str_len stays the same because that's the length in bytes
return (str_val, pos + str_len)
def unser_array(self, buf, pos):
arr_len, pos = self.unser_int(buf, pos + 1)
arr = []
for i in range(arr_len):
arr_item, pos = self.loads_recursive(buf, pos)
arr.append(arr_item)
if not self.mutable:
arr = tuple(arr)
return arr, pos
def unser_object(self, buf, pos):
obj_len, pos = self.unser_int(buf, pos + 1)
if self.mutable:
obj = {}
else:
keys = []
vals = []
for i in range(obj_len):
key, pos = self.unser_utf8_string(buf, pos)
val, pos = self.loads_recursive(buf, pos)
if self.mutable:
obj[key] = val
else:
keys.append(key)
vals.append(val)
if not self.mutable:
obj = _BunserDict(keys, vals)
return obj, pos
def unser_template(self, buf, pos):
val_type = _buf_pos(buf, pos + 1)
if val_type != BSER_ARRAY:
raise RuntimeError('Expect ARRAY to follow TEMPLATE')
# force UTF-8 on keys
keys_bunser = Bunser(mutable=self.mutable, value_encoding='utf-8')
keys, pos = keys_bunser.unser_array(buf, pos + 1)
nitems, pos = self.unser_int(buf, pos)
arr = []
for i in range(nitems):
if self.mutable:
obj = {}
else:
vals = []
for keyidx in range(len(keys)):
if _buf_pos(buf, pos) == BSER_SKIP:
pos += 1
ele = None
else:
ele, pos = self.loads_recursive(buf, pos)
if self.mutable:
key = keys[keyidx]
obj[key] = ele
else:
vals.append(ele)
if not self.mutable:
obj = _BunserDict(keys, vals)
arr.append(obj)
return arr, pos
def loads_recursive(self, buf, pos):
val_type = _buf_pos(buf, pos)
if (val_type == BSER_INT8 or val_type == BSER_INT16 or
val_type == BSER_INT32 or val_type == BSER_INT64):
return self.unser_int(buf, pos)
elif val_type == BSER_REAL:
val = struct.unpack_from(b'=d', buf, pos + 1)[0]
return (val, pos + 9)
elif val_type == BSER_TRUE:
return (True, pos + 1)
elif val_type == BSER_FALSE:
return (False, pos + 1)
elif val_type == BSER_NULL:
return (None, pos + 1)
elif val_type == BSER_BYTESTRING:
return self.unser_bytestring(buf, pos)
elif val_type == BSER_UTF8STRING:
return self.unser_utf8_string(buf, pos)
elif val_type == BSER_ARRAY:
return self.unser_array(buf, pos)
elif val_type == BSER_OBJECT:
return self.unser_object(buf, pos)
elif val_type == BSER_TEMPLATE:
return self.unser_template(buf, pos)
else:
raise ValueError('unhandled bser opcode 0x%s' %
binascii.hexlify(val_type).decode('ascii'))
def _pdu_info_helper(buf):
if buf[0:2] == EMPTY_HEADER[0:2]:
bser_version = 1
bser_capabilities = 0
expected_len, pos2 = Bunser.unser_int(buf, 2)
elif buf[0:2] == EMPTY_HEADER_V2[0:2]:
if len(buf) < 8:
raise ValueError('Invalid BSER header')
bser_version = 2
bser_capabilities = struct.unpack_from("I", buf, 2)[0]
expected_len, pos2 = Bunser.unser_int(buf, 6)
else:
raise ValueError('Invalid BSER header')
return bser_version, bser_capabilities, expected_len, pos2
def pdu_info(buf):
info = _pdu_info_helper(buf)
return info[0], info[1], info[2] + info[3]
def pdu_len(buf):
info = _pdu_info_helper(buf)
return info[2] + info[3]
def loads(buf, mutable=True, value_encoding=None, value_errors=None):
"""Deserialize a BSER-encoded blob.
@param buf: The buffer to deserialize.
@type buf: bytes
@param mutable: Whether to return mutable results.
@type mutable: bool
@param value_encoding: Optional codec to use to decode values. If
unspecified or None, return values as bytestrings.
@type value_encoding: str
@param value_errors: Optional error handler for codec. 'strict' by default.
The other most common argument is 'surrogateescape' on
Python 3. If value_encoding is None, this is ignored.
@type value_errors: str
"""
info = _pdu_info_helper(buf)
expected_len = info[2]
pos = info[3]
if len(buf) != expected_len + pos:
raise ValueError('bser data len != header len')
bunser = Bunser(mutable=mutable, value_encoding=value_encoding,
value_errors=value_errors)
return bunser.loads_recursive(buf, pos)[0]
def load(fp, mutable=True, value_encoding=None, value_errors=None):
from . import load
return load.load(fp, mutable, value_encoding, value_errors)