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# Copyright (C) 2008, 2009, 2010 Canonical Ltd
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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"""Core compression logic for compressing streams of related files."""
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from bzrlib.btree_index import BTreeBuilder
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from bzrlib.lru_cache import LRUSizeCache
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from bzrlib.tsort import topo_sort
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from bzrlib.versionedfile import (
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ChunkedContentFactory,
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FulltextContentFactory,
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# Minimum number of uncompressed bytes to try fetch at once when retrieving
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# groupcompress blocks.
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_USE_LZMA = False and (pylzma is not None)
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# osutils.sha_string('')
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_null_sha1 = 'da39a3ee5e6b4b0d3255bfef95601890afd80709'
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def sort_gc_optimal(parent_map):
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"""Sort and group the keys in parent_map into groupcompress order.
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groupcompress is defined (currently) as reverse-topological order, grouped
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:return: A sorted-list of keys
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# groupcompress ordering is approximately reverse topological,
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# properly grouped by file-id.
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for key, value in parent_map.iteritems():
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if isinstance(key, str) or len(key) == 1:
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per_prefix_map[prefix][key] = value
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per_prefix_map[prefix] = {key: value}
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for prefix in sorted(per_prefix_map):
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present_keys.extend(reversed(topo_sort(per_prefix_map[prefix])))
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# The max zlib window size is 32kB, so if we set 'max_size' output of the
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# decompressor to the requested bytes + 32kB, then we should guarantee
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# num_bytes coming out.
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_ZLIB_DECOMP_WINDOW = 32*1024
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class GroupCompressBlock(object):
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"""An object which maintains the internal structure of the compressed data.
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This tracks the meta info (start of text, length, type, etc.)
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# Group Compress Block v1 Zlib
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GCB_HEADER = 'gcb1z\n'
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# Group Compress Block v1 Lzma
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GCB_LZ_HEADER = 'gcb1l\n'
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GCB_KNOWN_HEADERS = (GCB_HEADER, GCB_LZ_HEADER)
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# map by key? or just order in file?
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self._compressor_name = None
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self._z_content = None
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self._z_content_decompressor = None
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self._z_content_length = None
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self._content_length = None
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self._content_chunks = None
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# This is the maximum number of bytes this object will reference if
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# everything is decompressed. However, if we decompress less than
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# everything... (this would cause some problems for LRUSizeCache)
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return self._content_length + self._z_content_length
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def _ensure_content(self, num_bytes=None):
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"""Make sure that content has been expanded enough.
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:param num_bytes: Ensure that we have extracted at least num_bytes of
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content. If None, consume everything
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if self._content_length is None:
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raise AssertionError('self._content_length should never be None')
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if num_bytes is None:
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num_bytes = self._content_length
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elif (self._content_length is not None
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and num_bytes > self._content_length):
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raise AssertionError(
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'requested num_bytes (%d) > content length (%d)'
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% (num_bytes, self._content_length))
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# Expand the content if required
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if self._content is None:
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if self._content_chunks is not None:
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self._content = ''.join(self._content_chunks)
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self._content_chunks = None
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if self._content is None:
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if self._z_content is None:
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raise AssertionError('No content to decompress')
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if self._z_content == '':
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elif self._compressor_name == 'lzma':
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# We don't do partial lzma decomp yet
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self._content = pylzma.decompress(self._z_content)
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elif self._compressor_name == 'zlib':
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# Start a zlib decompressor
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if num_bytes * 4 > self._content_length * 3:
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# If we are requesting more that 3/4ths of the content,
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# just extract the whole thing in a single pass
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num_bytes = self._content_length
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self._content = zlib.decompress(self._z_content)
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self._z_content_decompressor = zlib.decompressobj()
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# Seed the decompressor with the uncompressed bytes, so
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# that the rest of the code is simplified
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self._content = self._z_content_decompressor.decompress(
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self._z_content, num_bytes + _ZLIB_DECOMP_WINDOW)
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if not self._z_content_decompressor.unconsumed_tail:
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self._z_content_decompressor = None
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raise AssertionError('Unknown compressor: %r'
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% self._compressor_name)
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# Any bytes remaining to be decompressed will be in the decompressors
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# Do we have enough bytes already?
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if len(self._content) >= num_bytes:
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# If we got this far, and don't have a decompressor, something is wrong
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if self._z_content_decompressor is None:
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raise AssertionError(
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'No decompressor to decompress %d bytes' % num_bytes)
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remaining_decomp = self._z_content_decompressor.unconsumed_tail
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if not remaining_decomp:
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raise AssertionError('Nothing left to decompress')
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needed_bytes = num_bytes - len(self._content)
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# We always set max_size to 32kB over the minimum needed, so that
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# zlib will give us as much as we really want.
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# TODO: If this isn't good enough, we could make a loop here,
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# that keeps expanding the request until we get enough
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self._content += self._z_content_decompressor.decompress(
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remaining_decomp, needed_bytes + _ZLIB_DECOMP_WINDOW)
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if len(self._content) < num_bytes:
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raise AssertionError('%d bytes wanted, only %d available'
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% (num_bytes, len(self._content)))
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if not self._z_content_decompressor.unconsumed_tail:
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# The stream is finished
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self._z_content_decompressor = None
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def _parse_bytes(self, bytes, pos):
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"""Read the various lengths from the header.
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This also populates the various 'compressed' buffers.
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:return: The position in bytes just after the last newline
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# At present, we have 2 integers for the compressed and uncompressed
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# content. In base10 (ascii) 14 bytes can represent > 1TB, so to avoid
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# checking too far, cap the search to 14 bytes.
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pos2 = bytes.index('\n', pos, pos + 14)
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self._z_content_length = int(bytes[pos:pos2])
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pos2 = bytes.index('\n', pos, pos + 14)
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self._content_length = int(bytes[pos:pos2])
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if len(bytes) != (pos + self._z_content_length):
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# XXX: Define some GCCorrupt error ?
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raise AssertionError('Invalid bytes: (%d) != %d + %d' %
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(len(bytes), pos, self._z_content_length))
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self._z_content = bytes[pos:]
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def from_bytes(cls, bytes):
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if bytes[:6] not in cls.GCB_KNOWN_HEADERS:
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raise ValueError('bytes did not start with any of %r'
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% (cls.GCB_KNOWN_HEADERS,))
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# XXX: why not testing the whole header ?
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out._compressor_name = 'zlib'
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elif bytes[4] == 'l':
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out._compressor_name = 'lzma'
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raise ValueError('unknown compressor: %r' % (bytes,))
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out._parse_bytes(bytes, 6)
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def extract(self, key, start, end, sha1=None):
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"""Extract the text for a specific key.
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:param key: The label used for this content
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:param sha1: TODO (should we validate only when sha1 is supplied?)
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:return: The bytes for the content
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if start == end == 0:
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self._ensure_content(end)
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# The bytes are 'f' or 'd' for the type, then a variable-length
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# base128 integer for the content size, then the actual content
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# We know that the variable-length integer won't be longer than 5
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# bytes (it takes 5 bytes to encode 2^32)
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c = self._content[start]
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raise ValueError('Unknown content control code: %s'
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content_len, len_len = decode_base128_int(
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self._content[start + 1:start + 6])
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content_start = start + 1 + len_len
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if end != content_start + content_len:
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raise ValueError('end != len according to field header'
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' %s != %s' % (end, content_start + content_len))
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bytes = self._content[content_start:end]
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bytes = apply_delta_to_source(self._content, content_start, end)
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def set_chunked_content(self, content_chunks, length):
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"""Set the content of this block to the given chunks."""
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# If we have lots of short lines, it is may be more efficient to join
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# the content ahead of time. If the content is <10MiB, we don't really
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# care about the extra memory consumption, so we can just pack it and
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# be done. However, timing showed 18s => 17.9s for repacking 1k revs of
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# mysql, which is below the noise margin
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self._content_length = length
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self._content_chunks = content_chunks
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self._z_content = None
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def set_content(self, content):
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"""Set the content of this block."""
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self._content_length = len(content)
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self._content = content
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self._z_content = None
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def _create_z_content_using_lzma(self):
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if self._content_chunks is not None:
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self._content = ''.join(self._content_chunks)
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self._content_chunks = None
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if self._content is None:
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raise AssertionError('Nothing to compress')
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self._z_content = pylzma.compress(self._content)
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self._z_content_length = len(self._z_content)
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def _create_z_content_from_chunks(self):
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compressor = zlib.compressobj(zlib.Z_DEFAULT_COMPRESSION)
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compressed_chunks = map(compressor.compress, self._content_chunks)
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compressed_chunks.append(compressor.flush())
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self._z_content = ''.join(compressed_chunks)
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self._z_content_length = len(self._z_content)
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def _create_z_content(self):
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if self._z_content is not None:
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self._create_z_content_using_lzma()
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if self._content_chunks is not None:
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self._create_z_content_from_chunks()
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self._z_content = zlib.compress(self._content)
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self._z_content_length = len(self._z_content)
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"""Encode the information into a byte stream."""
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self._create_z_content()
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header = self.GCB_LZ_HEADER
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header = self.GCB_HEADER
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'%d\n%d\n' % (self._z_content_length, self._content_length),
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return ''.join(chunks)
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def _dump(self, include_text=False):
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"""Take this block, and spit out a human-readable structure.
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:param include_text: Inserts also include text bits, chose whether you
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want this displayed in the dump or not.
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:return: A dump of the given block. The layout is something like:
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[('f', length), ('d', delta_length, text_length, [delta_info])]
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delta_info := [('i', num_bytes, text), ('c', offset, num_bytes),
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self._ensure_content()
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while pos < self._content_length:
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kind = self._content[pos]
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if kind not in ('f', 'd'):
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raise ValueError('invalid kind character: %r' % (kind,))
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content_len, len_len = decode_base128_int(
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self._content[pos:pos + 5])
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if content_len + pos > self._content_length:
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raise ValueError('invalid content_len %d for record @ pos %d'
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% (content_len, pos - len_len - 1))
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if kind == 'f': # Fulltext
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text = self._content[pos:pos+content_len]
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result.append(('f', content_len, text))
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result.append(('f', content_len))
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elif kind == 'd': # Delta
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delta_content = self._content[pos:pos+content_len]
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# The first entry in a delta is the decompressed length
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decomp_len, delta_pos = decode_base128_int(delta_content)
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result.append(('d', content_len, decomp_len, delta_info))
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while delta_pos < content_len:
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c = ord(delta_content[delta_pos])
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delta_pos) = decode_copy_instruction(delta_content, c,
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text = self._content[offset:offset+length]
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delta_info.append(('c', offset, length, text))
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delta_info.append(('c', offset, length))
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measured_len += length
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txt = delta_content[delta_pos:delta_pos+c]
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delta_info.append(('i', c, txt))
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if delta_pos != content_len:
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raise ValueError('Delta consumed a bad number of bytes:'
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' %d != %d' % (delta_pos, content_len))
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if measured_len != decomp_len:
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raise ValueError('Delta claimed fulltext was %d bytes, but'
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' extraction resulted in %d bytes'
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% (decomp_len, measured_len))
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class _LazyGroupCompressFactory(object):
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"""Yield content from a GroupCompressBlock on demand."""
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def __init__(self, key, parents, manager, start, end, first):
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"""Create a _LazyGroupCompressFactory
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:param key: The key of just this record
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:param parents: The parents of this key (possibly None)
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:param gc_block: A GroupCompressBlock object
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:param start: Offset of the first byte for this record in the
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:param end: Offset of the byte just after the end of this record
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(ie, bytes = content[start:end])
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:param first: Is this the first Factory for the given block?
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self.parents = parents
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# Note: This attribute coupled with Manager._factories creates a
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# reference cycle. Perhaps we would rather use a weakref(), or
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# find an appropriate time to release the ref. After the first
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# get_bytes_as call? After Manager.get_record_stream() returns
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self._manager = manager
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self.storage_kind = 'groupcompress-block'
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self.storage_kind = 'groupcompress-block-ref'
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return '%s(%s, first=%s)' % (self.__class__.__name__,
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self.key, self._first)
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def get_bytes_as(self, storage_kind):
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if storage_kind == self.storage_kind:
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# wire bytes, something...
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return self._manager._wire_bytes()
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if storage_kind in ('fulltext', 'chunked'):
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if self._bytes is None:
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# Grab and cache the raw bytes for this entry
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# and break the ref-cycle with _manager since we don't need it
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self._manager._prepare_for_extract()
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block = self._manager._block
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self._bytes = block.extract(self.key, self._start, self._end)
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# There are code paths that first extract as fulltext, and then
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# extract as storage_kind (smart fetch). So we don't break the
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# refcycle here, but instead in manager.get_record_stream()
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if storage_kind == 'fulltext':
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raise errors.UnavailableRepresentation(self.key, storage_kind,
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class _LazyGroupContentManager(object):
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"""This manages a group of _LazyGroupCompressFactory objects."""
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_max_cut_fraction = 0.75 # We allow a block to be trimmed to 75% of
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# current size, and still be considered
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_full_block_size = 4*1024*1024
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_full_mixed_block_size = 2*1024*1024
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_full_enough_block_size = 3*1024*1024 # size at which we won't repack
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_full_enough_mixed_block_size = 2*768*1024 # 1.5MB
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def __init__(self, block):
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# We need to preserve the ordering
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def add_factory(self, key, parents, start, end):
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if not self._factories:
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# Note that this creates a reference cycle....
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factory = _LazyGroupCompressFactory(key, parents, self,
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start, end, first=first)
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# max() works here, but as a function call, doing a compare seems to be
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# significantly faster, timeit says 250ms for max() and 100ms for the
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if end > self._last_byte:
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self._last_byte = end
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self._factories.append(factory)
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def get_record_stream(self):
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"""Get a record for all keys added so far."""
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for factory in self._factories:
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# Break the ref-cycle
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factory._bytes = None
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factory._manager = None
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# TODO: Consider setting self._factories = None after the above loop,
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# as it will break the reference cycle
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def _trim_block(self, last_byte):
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"""Create a new GroupCompressBlock, with just some of the content."""
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# None of the factories need to be adjusted, because the content is
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# located in an identical place. Just that some of the unreferenced
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# trailing bytes are stripped
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trace.mutter('stripping trailing bytes from groupcompress block'
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' %d => %d', self._block._content_length, last_byte)
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new_block = GroupCompressBlock()
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self._block._ensure_content(last_byte)
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new_block.set_content(self._block._content[:last_byte])
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self._block = new_block
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def _rebuild_block(self):
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"""Create a new GroupCompressBlock with only the referenced texts."""
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compressor = GroupCompressor()
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old_length = self._block._content_length
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for factory in self._factories:
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bytes = factory.get_bytes_as('fulltext')
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(found_sha1, start_point, end_point,
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type) = compressor.compress(factory.key, bytes, factory.sha1)
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# Now update this factory with the new offsets, etc
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factory.sha1 = found_sha1
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factory._start = start_point
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factory._end = end_point
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self._last_byte = end_point
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new_block = compressor.flush()
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# TODO: Should we check that new_block really *is* smaller than the old
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# block? It seems hard to come up with a method that it would
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# expand, since we do full compression again. Perhaps based on a
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# request that ends up poorly ordered?
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delta = time.time() - tstart
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self._block = new_block
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trace.mutter('creating new compressed block on-the-fly in %.3fs'
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' %d bytes => %d bytes', delta, old_length,
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self._block._content_length)
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def _prepare_for_extract(self):
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"""A _LazyGroupCompressFactory is about to extract to fulltext."""
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# We expect that if one child is going to fulltext, all will be. This
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# helps prevent all of them from extracting a small amount at a time.
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# Which in itself isn't terribly expensive, but resizing 2MB 32kB at a
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# time (self._block._content) is a little expensive.
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self._block._ensure_content(self._last_byte)
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def _check_rebuild_action(self):
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"""Check to see if our block should be repacked."""
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for factory in self._factories:
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total_bytes_used += factory._end - factory._start
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if last_byte_used < factory._end:
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last_byte_used = factory._end
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# If we are using more than half of the bytes from the block, we have
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# nothing else to check
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if total_bytes_used * 2 >= self._block._content_length:
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return None, last_byte_used, total_bytes_used
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# We are using less than 50% of the content. Is the content we are
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# using at the beginning of the block? If so, we can just trim the
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# tail, rather than rebuilding from scratch.
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if total_bytes_used * 2 > last_byte_used:
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return 'trim', last_byte_used, total_bytes_used
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# We are using a small amount of the data, and it isn't just packed
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# nicely at the front, so rebuild the content.
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# Note: This would be *nicer* as a strip-data-from-group, rather than
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# building it up again from scratch
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# It might be reasonable to consider the fulltext sizes for
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# different bits when deciding this, too. As you may have a small
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# fulltext, and a trivial delta, and you are just trading around
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# for another fulltext. If we do a simple 'prune' you may end up
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# expanding many deltas into fulltexts, as well.
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# If we build a cheap enough 'strip', then we could try a strip,
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# if that expands the content, we then rebuild.
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return 'rebuild', last_byte_used, total_bytes_used
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def check_is_well_utilized(self):
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"""Is the current block considered 'well utilized'?
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This heuristic asks if the current block considers itself to be a fully
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developed group, rather than just a loose collection of data.
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if len(self._factories) == 1:
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# A block of length 1 could be improved by combining with other
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# groups - don't look deeper. Even larger than max size groups
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# could compress well with adjacent versions of the same thing.
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action, last_byte_used, total_bytes_used = self._check_rebuild_action()
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block_size = self._block._content_length
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if total_bytes_used < block_size * self._max_cut_fraction:
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# This block wants to trim itself small enough that we want to
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# consider it under-utilized.
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# TODO: This code is meant to be the twin of _insert_record_stream's
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# 'start_new_block' logic. It would probably be better to factor
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# out that logic into a shared location, so that it stays
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# We currently assume a block is properly utilized whenever it is >75%
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# of the size of a 'full' block. In normal operation, a block is
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# considered full when it hits 4MB of same-file content. So any block
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# >3MB is 'full enough'.
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# The only time this isn't true is when a given block has large-object
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# content. (a single file >4MB, etc.)
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# Under these circumstances, we allow a block to grow to
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# 2 x largest_content. Which means that if a given block had a large
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# object, it may actually be under-utilized. However, given that this
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# is 'pack-on-the-fly' it is probably reasonable to not repack large
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# content blobs on-the-fly. Note that because we return False for all
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# 1-item blobs, we will repack them; we may wish to reevaluate our
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# treatment of large object blobs in the future.
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if block_size >= self._full_enough_block_size:
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# If a block is <3MB, it still may be considered 'full' if it contains
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# mixed content. The current rule is 2MB of mixed content is considered
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# full. So check to see if this block contains mixed content, and
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# set the threshold appropriately.
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for factory in self._factories:
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prefix = factory.key[:-1]
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if common_prefix is None:
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common_prefix = prefix
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elif prefix != common_prefix:
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# Mixed content, check the size appropriately
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if block_size >= self._full_enough_mixed_block_size:
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# The content failed both the mixed check and the single-content check
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# so obviously it is not fully utilized
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# TODO: there is one other constraint that isn't being checked
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# namely, that the entries in the block are in the appropriate
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# order. For example, you could insert the entries in exactly
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# reverse groupcompress order, and we would think that is ok.
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# (all the right objects are in one group, and it is fully
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# utilized, etc.) For now, we assume that case is rare,
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# especially since we should always fetch in 'groupcompress'
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def _check_rebuild_block(self):
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action, last_byte_used, total_bytes_used = self._check_rebuild_action()
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self._trim_block(last_byte_used)
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elif action == 'rebuild':
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self._rebuild_block()
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raise ValueError('unknown rebuild action: %r' % (action,))
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def _wire_bytes(self):
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"""Return a byte stream suitable for transmitting over the wire."""
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self._check_rebuild_block()
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# The outer block starts with:
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# 'groupcompress-block\n'
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# <length of compressed key info>\n
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# <length of uncompressed info>\n
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# <length of gc block>\n
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lines = ['groupcompress-block\n']
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# The minimal info we need is the key, the start offset, and the
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# parents. The length and type are encoded in the record itself.
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# However, passing in the other bits makes it easier. The list of
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# keys, and the start offset, the length
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# 1 line with parents, '' for ()
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# 1 line for start offset
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# 1 line for end byte
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for factory in self._factories:
665
key_bytes = '\x00'.join(factory.key)
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parents = factory.parents
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parent_bytes = 'None:'
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parent_bytes = '\t'.join('\x00'.join(key) for key in parents)
671
record_header = '%s\n%s\n%d\n%d\n' % (
672
key_bytes, parent_bytes, factory._start, factory._end)
673
header_lines.append(record_header)
674
# TODO: Can we break the refcycle at this point and set
675
# factory._manager = None?
676
header_bytes = ''.join(header_lines)
678
header_bytes_len = len(header_bytes)
679
z_header_bytes = zlib.compress(header_bytes)
681
z_header_bytes_len = len(z_header_bytes)
682
block_bytes = self._block.to_bytes()
683
lines.append('%d\n%d\n%d\n' % (z_header_bytes_len, header_bytes_len,
685
lines.append(z_header_bytes)
686
lines.append(block_bytes)
687
del z_header_bytes, block_bytes
688
return ''.join(lines)
691
def from_bytes(cls, bytes):
692
# TODO: This does extra string copying, probably better to do it a
694
(storage_kind, z_header_len, header_len,
695
block_len, rest) = bytes.split('\n', 4)
697
if storage_kind != 'groupcompress-block':
698
raise ValueError('Unknown storage kind: %s' % (storage_kind,))
699
z_header_len = int(z_header_len)
700
if len(rest) < z_header_len:
701
raise ValueError('Compressed header len shorter than all bytes')
702
z_header = rest[:z_header_len]
703
header_len = int(header_len)
704
header = zlib.decompress(z_header)
705
if len(header) != header_len:
706
raise ValueError('invalid length for decompressed bytes')
708
block_len = int(block_len)
709
if len(rest) != z_header_len + block_len:
710
raise ValueError('Invalid length for block')
711
block_bytes = rest[z_header_len:]
713
# So now we have a valid GCB, we just need to parse the factories that
715
header_lines = header.split('\n')
717
last = header_lines.pop()
719
raise ValueError('header lines did not end with a trailing'
721
if len(header_lines) % 4 != 0:
722
raise ValueError('The header was not an even multiple of 4 lines')
723
block = GroupCompressBlock.from_bytes(block_bytes)
726
for start in xrange(0, len(header_lines), 4):
728
key = tuple(header_lines[start].split('\x00'))
729
parents_line = header_lines[start+1]
730
if parents_line == 'None:':
733
parents = tuple([tuple(segment.split('\x00'))
734
for segment in parents_line.split('\t')
736
start_offset = int(header_lines[start+2])
737
end_offset = int(header_lines[start+3])
738
result.add_factory(key, parents, start_offset, end_offset)
742
def network_block_to_records(storage_kind, bytes, line_end):
743
if storage_kind != 'groupcompress-block':
744
raise ValueError('Unknown storage kind: %s' % (storage_kind,))
745
manager = _LazyGroupContentManager.from_bytes(bytes)
746
return manager.get_record_stream()
749
class _CommonGroupCompressor(object):
752
"""Create a GroupCompressor."""
757
self.labels_deltas = {}
758
self._delta_index = None # Set by the children
759
self._block = GroupCompressBlock()
761
def compress(self, key, bytes, expected_sha, nostore_sha=None, soft=False):
762
"""Compress lines with label key.
764
:param key: A key tuple. It is stored in the output
765
for identification of the text during decompression. If the last
766
element is 'None' it is replaced with the sha1 of the text -
768
:param bytes: The bytes to be compressed
769
:param expected_sha: If non-None, the sha the lines are believed to
770
have. During compression the sha is calculated; a mismatch will
772
:param nostore_sha: If the computed sha1 sum matches, we will raise
773
ExistingContent rather than adding the text.
774
:param soft: Do a 'soft' compression. This means that we require larger
775
ranges to match to be considered for a copy command.
777
:return: The sha1 of lines, the start and end offsets in the delta, and
778
the type ('fulltext' or 'delta').
780
:seealso VersionedFiles.add_lines:
782
if not bytes: # empty, like a dir entry, etc
783
if nostore_sha == _null_sha1:
784
raise errors.ExistingContent()
785
return _null_sha1, 0, 0, 'fulltext'
786
# we assume someone knew what they were doing when they passed it in
787
if expected_sha is not None:
790
sha1 = osutils.sha_string(bytes)
791
if nostore_sha is not None:
792
if sha1 == nostore_sha:
793
raise errors.ExistingContent()
795
key = key[:-1] + ('sha1:' + sha1,)
797
start, end, type = self._compress(key, bytes, len(bytes) / 2, soft)
798
return sha1, start, end, type
800
def _compress(self, key, bytes, max_delta_size, soft=False):
801
"""Compress lines with label key.
803
:param key: A key tuple. It is stored in the output for identification
804
of the text during decompression.
806
:param bytes: The bytes to be compressed
808
:param max_delta_size: The size above which we issue a fulltext instead
811
:param soft: Do a 'soft' compression. This means that we require larger
812
ranges to match to be considered for a copy command.
814
:return: The sha1 of lines, the start and end offsets in the delta, and
815
the type ('fulltext' or 'delta').
817
raise NotImplementedError(self._compress)
819
def extract(self, key):
820
"""Extract a key previously added to the compressor.
822
:param key: The key to extract.
823
:return: An iterable over bytes and the sha1.
825
(start_byte, start_chunk, end_byte, end_chunk) = self.labels_deltas[key]
826
delta_chunks = self.chunks[start_chunk:end_chunk]
827
stored_bytes = ''.join(delta_chunks)
828
if stored_bytes[0] == 'f':
829
fulltext_len, offset = decode_base128_int(stored_bytes[1:10])
830
data_len = fulltext_len + 1 + offset
831
if data_len != len(stored_bytes):
832
raise ValueError('Index claimed fulltext len, but stored bytes'
834
% (len(stored_bytes), data_len))
835
bytes = stored_bytes[offset + 1:]
837
# XXX: This is inefficient at best
838
source = ''.join(self.chunks[:start_chunk])
839
if stored_bytes[0] != 'd':
840
raise ValueError('Unknown content kind, bytes claim %s'
841
% (stored_bytes[0],))
842
delta_len, offset = decode_base128_int(stored_bytes[1:10])
843
data_len = delta_len + 1 + offset
844
if data_len != len(stored_bytes):
845
raise ValueError('Index claimed delta len, but stored bytes'
847
% (len(stored_bytes), data_len))
848
bytes = apply_delta(source, stored_bytes[offset + 1:])
849
bytes_sha1 = osutils.sha_string(bytes)
850
return bytes, bytes_sha1
853
"""Finish this group, creating a formatted stream.
855
After calling this, the compressor should no longer be used
857
# TODO: this causes us to 'bloat' to 2x the size of content in the
858
# group. This has an impact for 'commit' of large objects.
859
# One possibility is to use self._content_chunks, and be lazy and
860
# only fill out self._content as a full string when we actually
861
# need it. That would at least drop the peak memory consumption
862
# for 'commit' down to ~1x the size of the largest file, at a
863
# cost of increased complexity within this code. 2x is still <<
864
# 3x the size of the largest file, so we are doing ok.
865
self._block.set_chunked_content(self.chunks, self.endpoint)
867
self._delta_index = None
871
"""Call this if you want to 'revoke' the last compression.
873
After this, the data structures will be rolled back, but you cannot do
876
self._delta_index = None
877
del self.chunks[self._last[0]:]
878
self.endpoint = self._last[1]
882
"""Return the overall compression ratio."""
883
return float(self.input_bytes) / float(self.endpoint)
886
class PythonGroupCompressor(_CommonGroupCompressor):
889
"""Create a GroupCompressor.
891
Used only if the pyrex version is not available.
893
super(PythonGroupCompressor, self).__init__()
894
self._delta_index = LinesDeltaIndex([])
895
# The actual content is managed by LinesDeltaIndex
896
self.chunks = self._delta_index.lines
898
def _compress(self, key, bytes, max_delta_size, soft=False):
899
"""see _CommonGroupCompressor._compress"""
900
input_len = len(bytes)
901
new_lines = osutils.split_lines(bytes)
902
out_lines, index_lines = self._delta_index.make_delta(
903
new_lines, bytes_length=input_len, soft=soft)
904
delta_length = sum(map(len, out_lines))
905
if delta_length > max_delta_size:
906
# The delta is longer than the fulltext, insert a fulltext
908
out_lines = ['f', encode_base128_int(input_len)]
909
out_lines.extend(new_lines)
910
index_lines = [False, False]
911
index_lines.extend([True] * len(new_lines))
913
# this is a worthy delta, output it
916
# Update the delta_length to include those two encoded integers
917
out_lines[1] = encode_base128_int(delta_length)
919
start = self.endpoint
920
chunk_start = len(self.chunks)
921
self._last = (chunk_start, self.endpoint)
922
self._delta_index.extend_lines(out_lines, index_lines)
923
self.endpoint = self._delta_index.endpoint
924
self.input_bytes += input_len
925
chunk_end = len(self.chunks)
926
self.labels_deltas[key] = (start, chunk_start,
927
self.endpoint, chunk_end)
928
return start, self.endpoint, type
931
class PyrexGroupCompressor(_CommonGroupCompressor):
932
"""Produce a serialised group of compressed texts.
934
It contains code very similar to SequenceMatcher because of having a similar
935
task. However some key differences apply:
936
- there is no junk, we want a minimal edit not a human readable diff.
937
- we don't filter very common lines (because we don't know where a good
938
range will start, and after the first text we want to be emitting minmal
940
- we chain the left side, not the right side
941
- we incrementally update the adjacency matrix as new lines are provided.
942
- we look for matches in all of the left side, so the routine which does
943
the analagous task of find_longest_match does not need to filter on the
948
super(PyrexGroupCompressor, self).__init__()
949
self._delta_index = DeltaIndex()
951
def _compress(self, key, bytes, max_delta_size, soft=False):
952
"""see _CommonGroupCompressor._compress"""
953
input_len = len(bytes)
954
# By having action/label/sha1/len, we can parse the group if the index
955
# was ever destroyed, we have the key in 'label', we know the final
956
# bytes are valid from sha1, and we know where to find the end of this
957
# record because of 'len'. (the delta record itself will store the
958
# total length for the expanded record)
959
# 'len: %d\n' costs approximately 1% increase in total data
960
# Having the labels at all costs us 9-10% increase, 38% increase for
961
# inventory pages, and 5.8% increase for text pages
962
# new_chunks = ['label:%s\nsha1:%s\n' % (label, sha1)]
963
if self._delta_index._source_offset != self.endpoint:
964
raise AssertionError('_source_offset != endpoint'
965
' somehow the DeltaIndex got out of sync with'
967
delta = self._delta_index.make_delta(bytes, max_delta_size)
970
enc_length = encode_base128_int(len(bytes))
971
len_mini_header = 1 + len(enc_length)
972
self._delta_index.add_source(bytes, len_mini_header)
973
new_chunks = ['f', enc_length, bytes]
976
enc_length = encode_base128_int(len(delta))
977
len_mini_header = 1 + len(enc_length)
978
new_chunks = ['d', enc_length, delta]
979
self._delta_index.add_delta_source(delta, len_mini_header)
981
start = self.endpoint
982
chunk_start = len(self.chunks)
983
# Now output these bytes
984
self._output_chunks(new_chunks)
985
self.input_bytes += input_len
986
chunk_end = len(self.chunks)
987
self.labels_deltas[key] = (start, chunk_start,
988
self.endpoint, chunk_end)
989
if not self._delta_index._source_offset == self.endpoint:
990
raise AssertionError('the delta index is out of sync'
991
'with the output lines %s != %s'
992
% (self._delta_index._source_offset, self.endpoint))
993
return start, self.endpoint, type
995
def _output_chunks(self, new_chunks):
996
"""Output some chunks.
998
:param new_chunks: The chunks to output.
1000
self._last = (len(self.chunks), self.endpoint)
1001
endpoint = self.endpoint
1002
self.chunks.extend(new_chunks)
1003
endpoint += sum(map(len, new_chunks))
1004
self.endpoint = endpoint
1007
def make_pack_factory(graph, delta, keylength, inconsistency_fatal=True):
1008
"""Create a factory for creating a pack based groupcompress.
1010
This is only functional enough to run interface tests, it doesn't try to
1011
provide a full pack environment.
1013
:param graph: Store a graph.
1014
:param delta: Delta compress contents.
1015
:param keylength: How long should keys be.
1017
def factory(transport):
1022
graph_index = BTreeBuilder(reference_lists=ref_length,
1023
key_elements=keylength)
1024
stream = transport.open_write_stream('newpack')
1025
writer = pack.ContainerWriter(stream.write)
1027
index = _GCGraphIndex(graph_index, lambda:True, parents=parents,
1028
add_callback=graph_index.add_nodes,
1029
inconsistency_fatal=inconsistency_fatal)
1030
access = knit._DirectPackAccess({})
1031
access.set_writer(writer, graph_index, (transport, 'newpack'))
1032
result = GroupCompressVersionedFiles(index, access, delta)
1033
result.stream = stream
1034
result.writer = writer
1039
def cleanup_pack_group(versioned_files):
1040
versioned_files.writer.end()
1041
versioned_files.stream.close()
1044
class _BatchingBlockFetcher(object):
1045
"""Fetch group compress blocks in batches.
1047
:ivar total_bytes: int of expected number of bytes needed to fetch the
1048
currently pending batch.
1051
def __init__(self, gcvf, locations):
1053
self.locations = locations
1055
self.batch_memos = {}
1056
self.memos_to_get = []
1057
self.total_bytes = 0
1058
self.last_read_memo = None
1061
def add_key(self, key):
1062
"""Add another to key to fetch.
1064
:return: The estimated number of bytes needed to fetch the batch so
1067
self.keys.append(key)
1068
index_memo, _, _, _ = self.locations[key]
1069
read_memo = index_memo[0:3]
1070
# Three possibilities for this read_memo:
1071
# - it's already part of this batch; or
1072
# - it's not yet part of this batch, but is already cached; or
1073
# - it's not yet part of this batch and will need to be fetched.
1074
if read_memo in self.batch_memos:
1075
# This read memo is already in this batch.
1076
return self.total_bytes
1078
cached_block = self.gcvf._group_cache[read_memo]
1080
# This read memo is new to this batch, and the data isn't cached
1082
self.batch_memos[read_memo] = None
1083
self.memos_to_get.append(read_memo)
1084
byte_length = read_memo[2]
1085
self.total_bytes += byte_length
1087
# This read memo is new to this batch, but cached.
1088
# Keep a reference to the cached block in batch_memos because it's
1089
# certain that we'll use it when this batch is processed, but
1090
# there's a risk that it would fall out of _group_cache between now
1092
self.batch_memos[read_memo] = cached_block
1093
return self.total_bytes
1095
def _flush_manager(self):
1096
if self.manager is not None:
1097
for factory in self.manager.get_record_stream():
1100
self.last_read_memo = None
1102
def yield_factories(self, full_flush=False):
1103
"""Yield factories for keys added since the last yield. They will be
1104
returned in the order they were added via add_key.
1106
:param full_flush: by default, some results may not be returned in case
1107
they can be part of the next batch. If full_flush is True, then
1108
all results are returned.
1110
if self.manager is None and not self.keys:
1112
# Fetch all memos in this batch.
1113
blocks = self.gcvf._get_blocks(self.memos_to_get)
1114
# Turn blocks into factories and yield them.
1115
memos_to_get_stack = list(self.memos_to_get)
1116
memos_to_get_stack.reverse()
1117
for key in self.keys:
1118
index_memo, _, parents, _ = self.locations[key]
1119
read_memo = index_memo[:3]
1120
if self.last_read_memo != read_memo:
1121
# We are starting a new block. If we have a
1122
# manager, we have found everything that fits for
1123
# now, so yield records
1124
for factory in self._flush_manager():
1126
# Now start a new manager.
1127
if memos_to_get_stack and memos_to_get_stack[-1] == read_memo:
1128
# The next block from _get_blocks will be the block we
1130
block_read_memo, block = blocks.next()
1131
if block_read_memo != read_memo:
1132
raise AssertionError(
1133
"block_read_memo out of sync with read_memo"
1134
"(%r != %r)" % (block_read_memo, read_memo))
1135
self.batch_memos[read_memo] = block
1136
memos_to_get_stack.pop()
1138
block = self.batch_memos[read_memo]
1139
self.manager = _LazyGroupContentManager(block)
1140
self.last_read_memo = read_memo
1141
start, end = index_memo[3:5]
1142
self.manager.add_factory(key, parents, start, end)
1144
for factory in self._flush_manager():
1147
self.batch_memos.clear()
1148
del self.memos_to_get[:]
1149
self.total_bytes = 0
1152
class GroupCompressVersionedFiles(VersionedFiles):
1153
"""A group-compress based VersionedFiles implementation."""
1155
def __init__(self, index, access, delta=True, _unadded_refs=None):
1156
"""Create a GroupCompressVersionedFiles object.
1158
:param index: The index object storing access and graph data.
1159
:param access: The access object storing raw data.
1160
:param delta: Whether to delta compress or just entropy compress.
1161
:param _unadded_refs: private parameter, don't use.
1164
self._access = access
1166
if _unadded_refs is None:
1168
self._unadded_refs = _unadded_refs
1169
self._group_cache = LRUSizeCache(max_size=50*1024*1024)
1170
self._fallback_vfs = []
1172
def without_fallbacks(self):
1173
"""Return a clone of this object without any fallbacks configured."""
1174
return GroupCompressVersionedFiles(self._index, self._access,
1175
self._delta, _unadded_refs=dict(self._unadded_refs))
1177
def add_lines(self, key, parents, lines, parent_texts=None,
1178
left_matching_blocks=None, nostore_sha=None, random_id=False,
1179
check_content=True):
1180
"""Add a text to the store.
1182
:param key: The key tuple of the text to add.
1183
:param parents: The parents key tuples of the text to add.
1184
:param lines: A list of lines. Each line must be a bytestring. And all
1185
of them except the last must be terminated with \n and contain no
1186
other \n's. The last line may either contain no \n's or a single
1187
terminating \n. If the lines list does meet this constraint the add
1188
routine may error or may succeed - but you will be unable to read
1189
the data back accurately. (Checking the lines have been split
1190
correctly is expensive and extremely unlikely to catch bugs so it
1191
is not done at runtime unless check_content is True.)
1192
:param parent_texts: An optional dictionary containing the opaque
1193
representations of some or all of the parents of version_id to
1194
allow delta optimisations. VERY IMPORTANT: the texts must be those
1195
returned by add_lines or data corruption can be caused.
1196
:param left_matching_blocks: a hint about which areas are common
1197
between the text and its left-hand-parent. The format is
1198
the SequenceMatcher.get_matching_blocks format.
1199
:param nostore_sha: Raise ExistingContent and do not add the lines to
1200
the versioned file if the digest of the lines matches this.
1201
:param random_id: If True a random id has been selected rather than
1202
an id determined by some deterministic process such as a converter
1203
from a foreign VCS. When True the backend may choose not to check
1204
for uniqueness of the resulting key within the versioned file, so
1205
this should only be done when the result is expected to be unique
1207
:param check_content: If True, the lines supplied are verified to be
1208
bytestrings that are correctly formed lines.
1209
:return: The text sha1, the number of bytes in the text, and an opaque
1210
representation of the inserted version which can be provided
1211
back to future add_lines calls in the parent_texts dictionary.
1213
self._index._check_write_ok()
1214
self._check_add(key, lines, random_id, check_content)
1216
# The caller might pass None if there is no graph data, but kndx
1217
# indexes can't directly store that, so we give them
1218
# an empty tuple instead.
1220
# double handling for now. Make it work until then.
1221
length = sum(map(len, lines))
1222
record = ChunkedContentFactory(key, parents, None, lines)
1223
sha1 = list(self._insert_record_stream([record], random_id=random_id,
1224
nostore_sha=nostore_sha))[0]
1225
return sha1, length, None
1227
def _add_text(self, key, parents, text, nostore_sha=None, random_id=False):
1228
"""See VersionedFiles._add_text()."""
1229
self._index._check_write_ok()
1230
self._check_add(key, None, random_id, check_content=False)
1231
if text.__class__ is not str:
1232
raise errors.BzrBadParameterUnicode("text")
1234
# The caller might pass None if there is no graph data, but kndx
1235
# indexes can't directly store that, so we give them
1236
# an empty tuple instead.
1238
# double handling for now. Make it work until then.
1240
record = FulltextContentFactory(key, parents, None, text)
1241
sha1 = list(self._insert_record_stream([record], random_id=random_id,
1242
nostore_sha=nostore_sha))[0]
1243
return sha1, length, None
1245
def add_fallback_versioned_files(self, a_versioned_files):
1246
"""Add a source of texts for texts not present in this knit.
1248
:param a_versioned_files: A VersionedFiles object.
1250
self._fallback_vfs.append(a_versioned_files)
1252
def annotate(self, key):
1253
"""See VersionedFiles.annotate."""
1254
ann = annotate.Annotator(self)
1255
return ann.annotate_flat(key)
1257
def get_annotator(self):
1258
return annotate.Annotator(self)
1260
def check(self, progress_bar=None, keys=None):
1261
"""See VersionedFiles.check()."""
1264
for record in self.get_record_stream(keys, 'unordered', True):
1265
record.get_bytes_as('fulltext')
1267
return self.get_record_stream(keys, 'unordered', True)
1269
def clear_cache(self):
1270
"""See VersionedFiles.clear_cache()"""
1271
self._group_cache.clear()
1272
self._index._graph_index.clear_cache()
1273
self._index._int_cache.clear()
1275
def _check_add(self, key, lines, random_id, check_content):
1276
"""check that version_id and lines are safe to add."""
1277
version_id = key[-1]
1278
if version_id is not None:
1279
if osutils.contains_whitespace(version_id):
1280
raise errors.InvalidRevisionId(version_id, self)
1281
self.check_not_reserved_id(version_id)
1282
# TODO: If random_id==False and the key is already present, we should
1283
# probably check that the existing content is identical to what is
1284
# being inserted, and otherwise raise an exception. This would make
1285
# the bundle code simpler.
1287
self._check_lines_not_unicode(lines)
1288
self._check_lines_are_lines(lines)
1290
def get_known_graph_ancestry(self, keys):
1291
"""Get a KnownGraph instance with the ancestry of keys."""
1292
# Note that this is identical to
1293
# KnitVersionedFiles.get_known_graph_ancestry, but they don't share
1295
parent_map, missing_keys = self._index.find_ancestry(keys)
1296
for fallback in self._fallback_vfs:
1297
if not missing_keys:
1299
(f_parent_map, f_missing_keys) = fallback._index.find_ancestry(
1301
parent_map.update(f_parent_map)
1302
missing_keys = f_missing_keys
1303
kg = _mod_graph.KnownGraph(parent_map)
1306
def get_parent_map(self, keys):
1307
"""Get a map of the graph parents of keys.
1309
:param keys: The keys to look up parents for.
1310
:return: A mapping from keys to parents. Absent keys are absent from
1313
return self._get_parent_map_with_sources(keys)[0]
1315
def _get_parent_map_with_sources(self, keys):
1316
"""Get a map of the parents of keys.
1318
:param keys: The keys to look up parents for.
1319
:return: A tuple. The first element is a mapping from keys to parents.
1320
Absent keys are absent from the mapping. The second element is a
1321
list with the locations each key was found in. The first element
1322
is the in-this-knit parents, the second the first fallback source,
1326
sources = [self._index] + self._fallback_vfs
1329
for source in sources:
1332
new_result = source.get_parent_map(missing)
1333
source_results.append(new_result)
1334
result.update(new_result)
1335
missing.difference_update(set(new_result))
1336
return result, source_results
1338
def _get_blocks(self, read_memos):
1339
"""Get GroupCompressBlocks for the given read_memos.
1341
:returns: a series of (read_memo, block) pairs, in the order they were
1345
for read_memo in read_memos:
1347
block = self._group_cache[read_memo]
1351
cached[read_memo] = block
1353
not_cached_seen = set()
1354
for read_memo in read_memos:
1355
if read_memo in cached:
1356
# Don't fetch what we already have
1358
if read_memo in not_cached_seen:
1359
# Don't try to fetch the same data twice
1361
not_cached.append(read_memo)
1362
not_cached_seen.add(read_memo)
1363
raw_records = self._access.get_raw_records(not_cached)
1364
for read_memo in read_memos:
1366
yield read_memo, cached[read_memo]
1368
# Read the block, and cache it.
1369
zdata = raw_records.next()
1370
block = GroupCompressBlock.from_bytes(zdata)
1371
self._group_cache[read_memo] = block
1372
cached[read_memo] = block
1373
yield read_memo, block
1375
def get_missing_compression_parent_keys(self):
1376
"""Return the keys of missing compression parents.
1378
Missing compression parents occur when a record stream was missing
1379
basis texts, or a index was scanned that had missing basis texts.
1381
# GroupCompress cannot currently reference texts that are not in the
1382
# group, so this is valid for now
1385
def get_record_stream(self, keys, ordering, include_delta_closure):
1386
"""Get a stream of records for keys.
1388
:param keys: The keys to include.
1389
:param ordering: Either 'unordered' or 'topological'. A topologically
1390
sorted stream has compression parents strictly before their
1392
:param include_delta_closure: If True then the closure across any
1393
compression parents will be included (in the opaque data).
1394
:return: An iterator of ContentFactory objects, each of which is only
1395
valid until the iterator is advanced.
1397
# keys might be a generator
1398
orig_keys = list(keys)
1402
if (not self._index.has_graph
1403
and ordering in ('topological', 'groupcompress')):
1404
# Cannot topological order when no graph has been stored.
1405
# but we allow 'as-requested' or 'unordered'
1406
ordering = 'unordered'
1408
remaining_keys = keys
1411
keys = set(remaining_keys)
1412
for content_factory in self._get_remaining_record_stream(keys,
1413
orig_keys, ordering, include_delta_closure):
1414
remaining_keys.discard(content_factory.key)
1415
yield content_factory
1417
except errors.RetryWithNewPacks, e:
1418
self._access.reload_or_raise(e)
1420
def _find_from_fallback(self, missing):
1421
"""Find whatever keys you can from the fallbacks.
1423
:param missing: A set of missing keys. This set will be mutated as keys
1424
are found from a fallback_vfs
1425
:return: (parent_map, key_to_source_map, source_results)
1426
parent_map the overall key => parent_keys
1427
key_to_source_map a dict from {key: source}
1428
source_results a list of (source: keys)
1431
key_to_source_map = {}
1433
for source in self._fallback_vfs:
1436
source_parents = source.get_parent_map(missing)
1437
parent_map.update(source_parents)
1438
source_parents = list(source_parents)
1439
source_results.append((source, source_parents))
1440
key_to_source_map.update((key, source) for key in source_parents)
1441
missing.difference_update(source_parents)
1442
return parent_map, key_to_source_map, source_results
1444
def _get_ordered_source_keys(self, ordering, parent_map, key_to_source_map):
1445
"""Get the (source, [keys]) list.
1447
The returned objects should be in the order defined by 'ordering',
1448
which can weave between different sources.
1449
:param ordering: Must be one of 'topological' or 'groupcompress'
1450
:return: List of [(source, [keys])] tuples, such that all keys are in
1451
the defined order, regardless of source.
1453
if ordering == 'topological':
1454
present_keys = topo_sort(parent_map)
1456
# ordering == 'groupcompress'
1457
# XXX: This only optimizes for the target ordering. We may need
1458
# to balance that with the time it takes to extract
1459
# ordering, by somehow grouping based on
1460
# locations[key][0:3]
1461
present_keys = sort_gc_optimal(parent_map)
1462
# Now group by source:
1464
current_source = None
1465
for key in present_keys:
1466
source = key_to_source_map.get(key, self)
1467
if source is not current_source:
1468
source_keys.append((source, []))
1469
current_source = source
1470
source_keys[-1][1].append(key)
1473
def _get_as_requested_source_keys(self, orig_keys, locations, unadded_keys,
1476
current_source = None
1477
for key in orig_keys:
1478
if key in locations or key in unadded_keys:
1480
elif key in key_to_source_map:
1481
source = key_to_source_map[key]
1484
if source is not current_source:
1485
source_keys.append((source, []))
1486
current_source = source
1487
source_keys[-1][1].append(key)
1490
def _get_io_ordered_source_keys(self, locations, unadded_keys,
1493
# This is the group the bytes are stored in, followed by the
1494
# location in the group
1495
return locations[key][0]
1496
present_keys = sorted(locations.iterkeys(), key=get_group)
1497
# We don't have an ordering for keys in the in-memory object, but
1498
# lets process the in-memory ones first.
1499
present_keys = list(unadded_keys) + present_keys
1500
# Now grab all of the ones from other sources
1501
source_keys = [(self, present_keys)]
1502
source_keys.extend(source_result)
1505
def _get_remaining_record_stream(self, keys, orig_keys, ordering,
1506
include_delta_closure):
1507
"""Get a stream of records for keys.
1509
:param keys: The keys to include.
1510
:param ordering: one of 'unordered', 'topological', 'groupcompress' or
1512
:param include_delta_closure: If True then the closure across any
1513
compression parents will be included (in the opaque data).
1514
:return: An iterator of ContentFactory objects, each of which is only
1515
valid until the iterator is advanced.
1518
locations = self._index.get_build_details(keys)
1519
unadded_keys = set(self._unadded_refs).intersection(keys)
1520
missing = keys.difference(locations)
1521
missing.difference_update(unadded_keys)
1522
(fallback_parent_map, key_to_source_map,
1523
source_result) = self._find_from_fallback(missing)
1524
if ordering in ('topological', 'groupcompress'):
1525
# would be better to not globally sort initially but instead
1526
# start with one key, recurse to its oldest parent, then grab
1527
# everything in the same group, etc.
1528
parent_map = dict((key, details[2]) for key, details in
1529
locations.iteritems())
1530
for key in unadded_keys:
1531
parent_map[key] = self._unadded_refs[key]
1532
parent_map.update(fallback_parent_map)
1533
source_keys = self._get_ordered_source_keys(ordering, parent_map,
1535
elif ordering == 'as-requested':
1536
source_keys = self._get_as_requested_source_keys(orig_keys,
1537
locations, unadded_keys, key_to_source_map)
1539
# We want to yield the keys in a semi-optimal (read-wise) ordering.
1540
# Otherwise we thrash the _group_cache and destroy performance
1541
source_keys = self._get_io_ordered_source_keys(locations,
1542
unadded_keys, source_result)
1544
yield AbsentContentFactory(key)
1545
# Batch up as many keys as we can until either:
1546
# - we encounter an unadded ref, or
1547
# - we run out of keys, or
1548
# - the total bytes to retrieve for this batch > BATCH_SIZE
1549
batcher = _BatchingBlockFetcher(self, locations)
1550
for source, keys in source_keys:
1553
if key in self._unadded_refs:
1554
# Flush batch, then yield unadded ref from
1556
for factory in batcher.yield_factories(full_flush=True):
1558
bytes, sha1 = self._compressor.extract(key)
1559
parents = self._unadded_refs[key]
1560
yield FulltextContentFactory(key, parents, sha1, bytes)
1562
if batcher.add_key(key) > BATCH_SIZE:
1563
# Ok, this batch is big enough. Yield some results.
1564
for factory in batcher.yield_factories():
1567
for factory in batcher.yield_factories(full_flush=True):
1569
for record in source.get_record_stream(keys, ordering,
1570
include_delta_closure):
1572
for factory in batcher.yield_factories(full_flush=True):
1575
def get_sha1s(self, keys):
1576
"""See VersionedFiles.get_sha1s()."""
1578
for record in self.get_record_stream(keys, 'unordered', True):
1579
if record.sha1 != None:
1580
result[record.key] = record.sha1
1582
if record.storage_kind != 'absent':
1583
result[record.key] = osutils.sha_string(
1584
record.get_bytes_as('fulltext'))
1587
def insert_record_stream(self, stream):
1588
"""Insert a record stream into this container.
1590
:param stream: A stream of records to insert.
1592
:seealso VersionedFiles.get_record_stream:
1594
# XXX: Setting random_id=True makes
1595
# test_insert_record_stream_existing_keys fail for groupcompress and
1596
# groupcompress-nograph, this needs to be revisited while addressing
1597
# 'bzr branch' performance issues.
1598
for _ in self._insert_record_stream(stream, random_id=False):
1601
def _insert_record_stream(self, stream, random_id=False, nostore_sha=None,
1603
"""Internal core to insert a record stream into this container.
1605
This helper function has a different interface than insert_record_stream
1606
to allow add_lines to be minimal, but still return the needed data.
1608
:param stream: A stream of records to insert.
1609
:param nostore_sha: If the sha1 of a given text matches nostore_sha,
1610
raise ExistingContent, rather than committing the new text.
1611
:param reuse_blocks: If the source is streaming from
1612
groupcompress-blocks, just insert the blocks as-is, rather than
1613
expanding the texts and inserting again.
1614
:return: An iterator over the sha1 of the inserted records.
1615
:seealso insert_record_stream:
1619
def get_adapter(adapter_key):
1621
return adapters[adapter_key]
1623
adapter_factory = adapter_registry.get(adapter_key)
1624
adapter = adapter_factory(self)
1625
adapters[adapter_key] = adapter
1627
# This will go up to fulltexts for gc to gc fetching, which isn't
1629
self._compressor = GroupCompressor()
1630
self._unadded_refs = {}
1633
bytes = self._compressor.flush().to_bytes()
1634
self._compressor = GroupCompressor()
1635
index, start, length = self._access.add_raw_records(
1636
[(None, len(bytes))], bytes)[0]
1638
for key, reads, refs in keys_to_add:
1639
nodes.append((key, "%d %d %s" % (start, length, reads), refs))
1640
self._index.add_records(nodes, random_id=random_id)
1641
self._unadded_refs = {}
1645
max_fulltext_len = 0
1646
max_fulltext_prefix = None
1647
insert_manager = None
1650
# XXX: TODO: remove this, it is just for safety checking for now
1651
inserted_keys = set()
1652
reuse_this_block = reuse_blocks
1653
for record in stream:
1654
# Raise an error when a record is missing.
1655
if record.storage_kind == 'absent':
1656
raise errors.RevisionNotPresent(record.key, self)
1658
if record.key in inserted_keys:
1659
trace.note('Insert claimed random_id=True,'
1660
' but then inserted %r two times', record.key)
1662
inserted_keys.add(record.key)
1664
# If the reuse_blocks flag is set, check to see if we can just
1665
# copy a groupcompress block as-is.
1666
# We only check on the first record (groupcompress-block) not
1667
# on all of the (groupcompress-block-ref) entries.
1668
# The reuse_this_block flag is then kept for as long as
1669
if record.storage_kind == 'groupcompress-block':
1670
# Check to see if we really want to re-use this block
1671
insert_manager = record._manager
1672
reuse_this_block = insert_manager.check_is_well_utilized()
1674
reuse_this_block = False
1675
if reuse_this_block:
1676
# We still want to reuse this block
1677
if record.storage_kind == 'groupcompress-block':
1678
# Insert the raw block into the target repo
1679
insert_manager = record._manager
1680
bytes = record._manager._block.to_bytes()
1681
_, start, length = self._access.add_raw_records(
1682
[(None, len(bytes))], bytes)[0]
1685
block_length = length
1686
if record.storage_kind in ('groupcompress-block',
1687
'groupcompress-block-ref'):
1688
if insert_manager is None:
1689
raise AssertionError('No insert_manager set')
1690
if insert_manager is not record._manager:
1691
raise AssertionError('insert_manager does not match'
1692
' the current record, we cannot be positive'
1693
' that the appropriate content was inserted.'
1695
value = "%d %d %d %d" % (block_start, block_length,
1696
record._start, record._end)
1697
nodes = [(record.key, value, (record.parents,))]
1698
# TODO: Consider buffering up many nodes to be added, not
1699
# sure how much overhead this has, but we're seeing
1700
# ~23s / 120s in add_records calls
1701
self._index.add_records(nodes, random_id=random_id)
1704
bytes = record.get_bytes_as('fulltext')
1705
except errors.UnavailableRepresentation:
1706
adapter_key = record.storage_kind, 'fulltext'
1707
adapter = get_adapter(adapter_key)
1708
bytes = adapter.get_bytes(record)
1709
if len(record.key) > 1:
1710
prefix = record.key[0]
1711
soft = (prefix == last_prefix)
1715
if max_fulltext_len < len(bytes):
1716
max_fulltext_len = len(bytes)
1717
max_fulltext_prefix = prefix
1718
(found_sha1, start_point, end_point,
1719
type) = self._compressor.compress(record.key,
1720
bytes, record.sha1, soft=soft,
1721
nostore_sha=nostore_sha)
1722
# delta_ratio = float(len(bytes)) / (end_point - start_point)
1723
# Check if we want to continue to include that text
1724
if (prefix == max_fulltext_prefix
1725
and end_point < 2 * max_fulltext_len):
1726
# As long as we are on the same file_id, we will fill at least
1727
# 2 * max_fulltext_len
1728
start_new_block = False
1729
elif end_point > 4*1024*1024:
1730
start_new_block = True
1731
elif (prefix is not None and prefix != last_prefix
1732
and end_point > 2*1024*1024):
1733
start_new_block = True
1735
start_new_block = False
1736
last_prefix = prefix
1738
self._compressor.pop_last()
1740
max_fulltext_len = len(bytes)
1741
(found_sha1, start_point, end_point,
1742
type) = self._compressor.compress(record.key, bytes,
1744
if record.key[-1] is None:
1745
key = record.key[:-1] + ('sha1:' + found_sha1,)
1748
self._unadded_refs[key] = record.parents
1750
as_st = static_tuple.StaticTuple.from_sequence
1751
if record.parents is not None:
1752
parents = as_st([as_st(p) for p in record.parents])
1755
refs = static_tuple.StaticTuple(parents)
1756
keys_to_add.append((key, '%d %d' % (start_point, end_point), refs))
1757
if len(keys_to_add):
1759
self._compressor = None
1761
def iter_lines_added_or_present_in_keys(self, keys, pb=None):
1762
"""Iterate over the lines in the versioned files from keys.
1764
This may return lines from other keys. Each item the returned
1765
iterator yields is a tuple of a line and a text version that that line
1766
is present in (not introduced in).
1768
Ordering of results is in whatever order is most suitable for the
1769
underlying storage format.
1771
If a progress bar is supplied, it may be used to indicate progress.
1772
The caller is responsible for cleaning up progress bars (because this
1776
* Lines are normalised by the underlying store: they will all have \n
1778
* Lines are returned in arbitrary order.
1780
:return: An iterator over (line, key).
1784
# we don't care about inclusions, the caller cares.
1785
# but we need to setup a list of records to visit.
1786
# we need key, position, length
1787
for key_idx, record in enumerate(self.get_record_stream(keys,
1788
'unordered', True)):
1789
# XXX: todo - optimise to use less than full texts.
1792
pb.update('Walking content', key_idx, total)
1793
if record.storage_kind == 'absent':
1794
raise errors.RevisionNotPresent(key, self)
1795
lines = osutils.split_lines(record.get_bytes_as('fulltext'))
1799
pb.update('Walking content', total, total)
1802
"""See VersionedFiles.keys."""
1803
if 'evil' in debug.debug_flags:
1804
trace.mutter_callsite(2, "keys scales with size of history")
1805
sources = [self._index] + self._fallback_vfs
1807
for source in sources:
1808
result.update(source.keys())
1812
class _GCBuildDetails(object):
1813
"""A blob of data about the build details.
1815
This stores the minimal data, which then allows compatibility with the old
1816
api, without taking as much memory.
1819
__slots__ = ('_index', '_group_start', '_group_end', '_basis_end',
1820
'_delta_end', '_parents')
1823
compression_parent = None
1825
def __init__(self, parents, position_info):
1826
self._parents = parents
1827
(self._index, self._group_start, self._group_end, self._basis_end,
1828
self._delta_end) = position_info
1831
return '%s(%s, %s)' % (self.__class__.__name__,
1832
self.index_memo, self._parents)
1835
def index_memo(self):
1836
return (self._index, self._group_start, self._group_end,
1837
self._basis_end, self._delta_end)
1840
def record_details(self):
1841
return static_tuple.StaticTuple(self.method, None)
1843
def __getitem__(self, offset):
1844
"""Compatibility thunk to act like a tuple."""
1846
return self.index_memo
1848
return self.compression_parent # Always None
1850
return self._parents
1852
return self.record_details
1854
raise IndexError('offset out of range')
1860
class _GCGraphIndex(object):
1861
"""Mapper from GroupCompressVersionedFiles needs into GraphIndex storage."""
1863
def __init__(self, graph_index, is_locked, parents=True,
1864
add_callback=None, track_external_parent_refs=False,
1865
inconsistency_fatal=True, track_new_keys=False):
1866
"""Construct a _GCGraphIndex on a graph_index.
1868
:param graph_index: An implementation of bzrlib.index.GraphIndex.
1869
:param is_locked: A callback, returns True if the index is locked and
1871
:param parents: If True, record knits parents, if not do not record
1873
:param add_callback: If not None, allow additions to the index and call
1874
this callback with a list of added GraphIndex nodes:
1875
[(node, value, node_refs), ...]
1876
:param track_external_parent_refs: As keys are added, keep track of the
1877
keys they reference, so that we can query get_missing_parents(),
1879
:param inconsistency_fatal: When asked to add records that are already
1880
present, and the details are inconsistent with the existing
1881
record, raise an exception instead of warning (and skipping the
1884
self._add_callback = add_callback
1885
self._graph_index = graph_index
1886
self._parents = parents
1887
self.has_graph = parents
1888
self._is_locked = is_locked
1889
self._inconsistency_fatal = inconsistency_fatal
1890
# GroupCompress records tend to have the same 'group' start + offset
1891
# repeated over and over, this creates a surplus of ints
1892
self._int_cache = {}
1893
if track_external_parent_refs:
1894
self._key_dependencies = knit._KeyRefs(
1895
track_new_keys=track_new_keys)
1897
self._key_dependencies = None
1899
def add_records(self, records, random_id=False):
1900
"""Add multiple records to the index.
1902
This function does not insert data into the Immutable GraphIndex
1903
backing the KnitGraphIndex, instead it prepares data for insertion by
1904
the caller and checks that it is safe to insert then calls
1905
self._add_callback with the prepared GraphIndex nodes.
1907
:param records: a list of tuples:
1908
(key, options, access_memo, parents).
1909
:param random_id: If True the ids being added were randomly generated
1910
and no check for existence will be performed.
1912
if not self._add_callback:
1913
raise errors.ReadOnlyError(self)
1914
# we hope there are no repositories with inconsistent parentage
1919
for (key, value, refs) in records:
1920
if not self._parents:
1924
raise errors.KnitCorrupt(self,
1925
"attempt to add node with parents "
1926
"in parentless index.")
1929
keys[key] = (value, refs)
1932
present_nodes = self._get_entries(keys)
1933
for (index, key, value, node_refs) in present_nodes:
1934
# Sometimes these are passed as a list rather than a tuple
1935
node_refs = static_tuple.as_tuples(node_refs)
1936
passed = static_tuple.as_tuples(keys[key])
1937
if node_refs != passed[1]:
1938
details = '%s %s %s' % (key, (value, node_refs), passed)
1939
if self._inconsistency_fatal:
1940
raise errors.KnitCorrupt(self, "inconsistent details"
1941
" in add_records: %s" %
1944
trace.warning("inconsistent details in skipped"
1945
" record: %s", details)
1951
for key, (value, node_refs) in keys.iteritems():
1952
result.append((key, value, node_refs))
1954
for key, (value, node_refs) in keys.iteritems():
1955
result.append((key, value))
1957
key_dependencies = self._key_dependencies
1958
if key_dependencies is not None:
1960
for key, value, refs in records:
1962
key_dependencies.add_references(key, parents)
1964
for key, value, refs in records:
1965
new_keys.add_key(key)
1966
self._add_callback(records)
1968
def _check_read(self):
1969
"""Raise an exception if reads are not permitted."""
1970
if not self._is_locked():
1971
raise errors.ObjectNotLocked(self)
1973
def _check_write_ok(self):
1974
"""Raise an exception if writes are not permitted."""
1975
if not self._is_locked():
1976
raise errors.ObjectNotLocked(self)
1978
def _get_entries(self, keys, check_present=False):
1979
"""Get the entries for keys.
1981
Note: Callers are responsible for checking that the index is locked
1982
before calling this method.
1984
:param keys: An iterable of index key tuples.
1989
for node in self._graph_index.iter_entries(keys):
1991
found_keys.add(node[1])
1993
# adapt parentless index to the rest of the code.
1994
for node in self._graph_index.iter_entries(keys):
1995
yield node[0], node[1], node[2], ()
1996
found_keys.add(node[1])
1998
missing_keys = keys.difference(found_keys)
2000
raise errors.RevisionNotPresent(missing_keys.pop(), self)
2002
def find_ancestry(self, keys):
2003
"""See CombinedGraphIndex.find_ancestry"""
2004
return self._graph_index.find_ancestry(keys, 0)
2006
def get_parent_map(self, keys):
2007
"""Get a map of the parents of keys.
2009
:param keys: The keys to look up parents for.
2010
:return: A mapping from keys to parents. Absent keys are absent from
2014
nodes = self._get_entries(keys)
2018
result[node[1]] = node[3][0]
2021
result[node[1]] = None
2024
def get_missing_parents(self):
2025
"""Return the keys of missing parents."""
2026
# Copied from _KnitGraphIndex.get_missing_parents
2027
# We may have false positives, so filter those out.
2028
self._key_dependencies.satisfy_refs_for_keys(
2029
self.get_parent_map(self._key_dependencies.get_unsatisfied_refs()))
2030
return frozenset(self._key_dependencies.get_unsatisfied_refs())
2032
def get_build_details(self, keys):
2033
"""Get the various build details for keys.
2035
Ghosts are omitted from the result.
2037
:param keys: An iterable of keys.
2038
:return: A dict of key:
2039
(index_memo, compression_parent, parents, record_details).
2041
opaque structure to pass to read_records to extract the raw
2044
Content that this record is built upon, may be None
2046
Logical parents of this node
2048
extra information about the content which needs to be passed to
2049
Factory.parse_record
2053
entries = self._get_entries(keys)
2054
for entry in entries:
2056
if not self._parents:
2059
parents = entry[3][0]
2060
details = _GCBuildDetails(parents, self._node_to_position(entry))
2061
result[key] = details
2065
"""Get all the keys in the collection.
2067
The keys are not ordered.
2070
return [node[1] for node in self._graph_index.iter_all_entries()]
2072
def _node_to_position(self, node):
2073
"""Convert an index value to position details."""
2074
bits = node[2].split(' ')
2075
# It would be nice not to read the entire gzip.
2076
# start and stop are put into _int_cache because they are very common.
2077
# They define the 'group' that an entry is in, and many groups can have
2078
# thousands of objects.
2079
# Branching Launchpad, for example, saves ~600k integers, at 12 bytes
2080
# each, or about 7MB. Note that it might be even more when you consider
2081
# how PyInt is allocated in separate slabs. And you can't return a slab
2082
# to the OS if even 1 int on it is in use. Note though that Python uses
2083
# a LIFO when re-using PyInt slots, which might cause more
2085
start = int(bits[0])
2086
start = self._int_cache.setdefault(start, start)
2088
stop = self._int_cache.setdefault(stop, stop)
2089
basis_end = int(bits[2])
2090
delta_end = int(bits[3])
2091
# We can't use StaticTuple here, because node[0] is a BTreeGraphIndex
2093
return (node[0], start, stop, basis_end, delta_end)
2095
def scan_unvalidated_index(self, graph_index):
2096
"""Inform this _GCGraphIndex that there is an unvalidated index.
2098
This allows this _GCGraphIndex to keep track of any missing
2099
compression parents we may want to have filled in to make those
2100
indices valid. It also allows _GCGraphIndex to track any new keys.
2102
:param graph_index: A GraphIndex
2104
key_dependencies = self._key_dependencies
2105
if key_dependencies is None:
2107
for node in graph_index.iter_all_entries():
2108
# Add parent refs from graph_index (and discard parent refs
2109
# that the graph_index has).
2110
key_dependencies.add_references(node[1], node[3][0])
2113
from bzrlib._groupcompress_py import (
2115
apply_delta_to_source,
2118
decode_copy_instruction,
2122
from bzrlib._groupcompress_pyx import (
2124
apply_delta_to_source,
2129
GroupCompressor = PyrexGroupCompressor
2130
except ImportError, e:
2131
osutils.failed_to_load_extension(e)
2132
GroupCompressor = PythonGroupCompressor
added
removed
bzrlib/groupcompress.py
