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immutable/layout.py: wrap to 80 cols, no functional changes

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This commit is contained in:
Brian Warner 2009-02-23 18:58:37 -07:00
parent 2be729b1e4
commit 9af9d8ae35
1 changed files with 28 additions and 22 deletions
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50
src/allmydata/immutable/layout.py
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@ -8,25 +8,26 @@ from allmydata.util.assertutil import precondition
from allmydata.storage.server import si_b2a
class LayoutInvalid(Exception):
""" There is something wrong with these bytes so they can't be interpreted as the kind of
immutable file that I know how to download. """
""" There is something wrong with these bytes so they can't be
interpreted as the kind of immutable file that I know how to download."""
pass
class RidiculouslyLargeURIExtensionBlock(LayoutInvalid):
""" When downloading a file, the length of the URI Extension Block was given as >= 2**32.
This means the share data must have been corrupted, or else the original uploader of the
file wrote a ridiculous value into the URI Extension Block length. """
""" When downloading a file, the length of the URI Extension Block was
given as >= 2**32. This means the share data must have been corrupted, or
else the original uploader of the file wrote a ridiculous value into the
URI Extension Block length."""
pass
class ShareVersionIncompatible(LayoutInvalid):
""" When downloading a share, its format was not one of the formats we know how to
parse. """
""" When downloading a share, its format was not one of the formats we
know how to parse."""
pass
"""
Share data is written in a file. At the start of the file, there is a series of four-byte
big-endian offset values, which indicate where each section starts. Each offset is measured from
the beginning of the share data.
Share data is written in a file. At the start of the file, there is a series
of four-byte big-endian offset values, which indicate where each section
starts. Each offset is measured from the beginning of the share data.
0x00: version number (=00 00 00 01)
0x04: block size # See Footnote 1 below.
@ -286,8 +287,9 @@ class ReadBucketProxy:
return self._reprstr
def _start_if_needed(self):
""" Returns a deferred that will be fired when I'm ready to return data, or errbacks if
the starting (header reading and parsing) process fails."""
""" Returns a deferred that will be fired when I'm ready to return
data, or errbacks if the starting (header reading and parsing)
process fails."""
if not self._started:
self._start()
return self._ready.when_fired()
@ -297,8 +299,9 @@ class ReadBucketProxy:
# TODO: for small shares, read the whole bucket in _start()
d = self._fetch_header()
d.addCallback(self._parse_offsets)
# XXX The following two callbacks implement a slightly faster/nicer way to get the ueb
# and sharehashtree, but it requires that the storage server be >= v1.3.0.
# XXX The following two callbacks implement a slightly faster/nicer
# way to get the ueb and sharehashtree, but it requires that the
# storage server be >= v1.3.0.
# d.addCallback(self._fetch_sharehashtree_and_ueb)
# d.addCallback(self._parse_sharehashtree_and_ueb)
def _fail_waiters(f):
@ -347,7 +350,8 @@ class ReadBucketProxy:
def _fetch_sharehashtree_and_ueb(self, offsets):
sharehashtree_size = offsets['uri_extension'] - offsets['share_hashes']
return self._read(offsets['share_hashes'], self.MAX_UEB_SIZE+sharehashtree_size)
return self._read(offsets['share_hashes'],
self.MAX_UEB_SIZE+sharehashtree_size)
def _parse_sharehashtree_and_ueb(self, data):
sharehashtree_size = self._offsets['uri_extension'] - self._offsets['share_hashes']
@ -422,8 +426,9 @@ class ReadBucketProxy:
return d
def _get_share_hashes_the_old_way(self):
""" Tahoe storage servers < v1.3.0 would return an error if you tried to read past the
end of the share, so we need to use the offset and read just that much."""
""" Tahoe storage servers < v1.3.0 would return an error if you tried
to read past the end of the share, so we need to use the offset and
read just that much."""
offset = self._offsets['share_hashes']
size = self._offsets['uri_extension'] - offset
if size % (2+HASH_SIZE) != 0:
@ -442,8 +447,9 @@ class ReadBucketProxy:
return d
def _get_uri_extension_the_old_way(self, unused=None):
""" Tahoe storage servers < v1.3.0 would return an error if you tried to read past the
end of the share, so we need to fetch the UEB size and then read just that much."""
""" Tahoe storage servers < v1.3.0 would return an error if you tried
to read past the end of the share, so we need to fetch the UEB size
and then read just that much."""
offset = self._offsets['uri_extension']
d = self._read(offset, self._fieldsize)
def _got_length(data):
@ -451,9 +457,9 @@ class ReadBucketProxy:
raise LayoutInvalid("not enough bytes to encode URI length -- should be %d bytes long, not %d " % (self._fieldsize, len(data),))
length = struct.unpack(self._fieldstruct, data)[0]
if length >= 2**31:
# URI extension blocks are around 419 bytes long, so this must be corrupted.
# Anyway, the foolscap interface schema for "read" will not allow >= 2**31 bytes
# length.
# URI extension blocks are around 419 bytes long, so this
# must be corrupted. Anyway, the foolscap interface schema
# for "read" will not allow >= 2**31 bytes length.
raise RidiculouslyLargeURIExtensionBlock(length)
return self._read(offset+self._fieldsize, length)