1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
|
# Copyright (C) 2007 Canonical Ltd
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
"""Container format for Bazaar data.
"Containers" and "records" are described in doc/developers/container-format.txt.
"""
import re
from bzrlib import errors
FORMAT_ONE = "Bazaar pack format 1 (introduced in 0.18)"
_whitespace_re = re.compile('[\t\n\x0b\x0c\r ]')
def _check_name(name):
"""Do some basic checking of 'name'.
At the moment, this just checks that there are no whitespace characters in a
name.
:raises InvalidRecordError: if name is not valid.
:seealso: _check_name_encoding
"""
if _whitespace_re.search(name) is not None:
raise errors.InvalidRecordError("%r is not a valid name." % (name,))
def _check_name_encoding(name):
"""Check that 'name' is valid UTF-8.
This is separate from _check_name because UTF-8 decoding is relatively
expensive, and we usually want to avoid it.
:raises InvalidRecordError: if name is not valid UTF-8.
"""
try:
name.decode('utf-8')
except UnicodeDecodeError, e:
raise errors.InvalidRecordError(str(e))
class ContainerWriter(object):
"""A class for writing containers."""
def __init__(self, write_func):
"""Constructor.
:param write_func: a callable that will be called when this
ContainerWriter needs to write some bytes.
"""
self.write_func = write_func
def begin(self):
"""Begin writing a container."""
self.write_func(FORMAT_ONE + "\n")
def end(self):
"""Finish writing a container."""
self.write_func("E")
def add_bytes_record(self, bytes, names):
"""Add a Bytes record with the given names."""
# Kind marker
self.write_func("B")
# Length
self.write_func(str(len(bytes)) + "\n")
# Names
for name in names:
# Make sure we're writing valid names. Note that we will leave a
# half-written record if a name is bad!
_check_name(name)
self.write_func(name + "\n")
# End of headers
self.write_func("\n")
# Finally, the contents.
self.write_func(bytes)
class BaseReader(object):
def __init__(self, source_file):
"""Constructor.
:param source_file: a file-like object with `read` and `readline`
methods.
"""
self._source = source_file
def reader_func(self, length=None):
return self._source.read(length)
def _read_line(self):
line = self._source.readline()
if not line.endswith('\n'):
raise errors.UnexpectedEndOfContainerError()
return line.rstrip('\n')
class ContainerReader(BaseReader):
"""A class for reading Bazaar's container format."""
def iter_records(self):
"""Iterate over the container, yielding each record as it is read.
Each yielded record will be a 2-tuple of (names, callable), where names
is a ``list`` and bytes is a function that takes one argument,
``max_length``.
You **must not** call the callable after advancing the interator to the
next record. That is, this code is invalid::
record_iter = container.iter_records()
names1, callable1 = record_iter.next()
names2, callable2 = record_iter.next()
bytes1 = callable1(None)
As it will give incorrect results and invalidate the state of the
ContainerReader.
:raises ContainerError: if any sort of containter corruption is
detected, e.g. UnknownContainerFormatError is the format of the
container is unrecognised.
:seealso: ContainerReader.read
"""
self._read_format()
return self._iter_records()
def iter_record_objects(self):
"""Iterate over the container, yielding each record as it is read.
Each yielded record will be an object with ``read`` and ``validate``
methods. Like with iter_records, it is not safe to use a record object
after advancing the iterator to yield next record.
:raises ContainerError: if any sort of containter corruption is
detected, e.g. UnknownContainerFormatError is the format of the
container is unrecognised.
:seealso: iter_records
"""
self._read_format()
return self._iter_record_objects()
def _iter_records(self):
for record in self._iter_record_objects():
yield record.read()
def _iter_record_objects(self):
while True:
record_kind = self.reader_func(1)
if record_kind == 'B':
# Bytes record.
reader = BytesRecordReader(self._source)
yield reader
elif record_kind == 'E':
# End marker. There are no more records.
return
elif record_kind == '':
# End of stream encountered, but no End Marker record seen, so
# this container is incomplete.
raise errors.UnexpectedEndOfContainerError()
else:
# Unknown record type.
raise errors.UnknownRecordTypeError(record_kind)
def _read_format(self):
format = self._read_line()
if format != FORMAT_ONE:
raise errors.UnknownContainerFormatError(format)
def validate(self):
"""Validate this container and its records.
Validating consumes the data stream just like iter_records and
iter_record_objects, so you cannot call it after
iter_records/iter_record_objects.
:raises ContainerError: if something is invalid.
"""
all_names = set()
for record_names, read_bytes in self.iter_records():
read_bytes(None)
for name in record_names:
_check_name_encoding(name)
# Check that the name is unique. Note that Python will refuse
# to decode non-shortest forms of UTF-8 encoding, so there is no
# risk that the same unicode string has been encoded two
# different ways.
if name in all_names:
raise errors.DuplicateRecordNameError(name)
all_names.add(name)
excess_bytes = self.reader_func(1)
if excess_bytes != '':
raise errors.ContainerHasExcessDataError(excess_bytes)
class BytesRecordReader(BaseReader):
def read(self):
"""Read this record.
You can either validate or read a record, you can't do both.
:returns: A tuple of (names, callable). The callable can be called
repeatedly to obtain the bytes for the record, with a max_length
argument. If max_length is None, returns all the bytes. Because
records can be arbitrarily large, using None is not recommended
unless you have reason to believe the content will fit in memory.
"""
# Read the content length.
length_line = self._read_line()
try:
length = int(length_line)
except ValueError:
raise errors.InvalidRecordError(
"%r is not a valid length." % (length_line,))
# Read the list of names.
names = []
while True:
name = self._read_line()
if name == '':
break
_check_name(name)
names.append(name)
self._remaining_length = length
return names, self._content_reader
def _content_reader(self, max_length):
if max_length is None:
length_to_read = self._remaining_length
else:
length_to_read = min(max_length, self._remaining_length)
self._remaining_length -= length_to_read
bytes = self.reader_func(length_to_read)
if len(bytes) != length_to_read:
raise errors.UnexpectedEndOfContainerError()
return bytes
def validate(self):
"""Validate this record.
You can either validate or read, you can't do both.
:raises ContainerError: if this record is invalid.
"""
names, read_bytes = self.read()
for name in names:
_check_name_encoding(name)
read_bytes(None)
|