/usr/lib/python3/dist-packages/gitdb/db/pack.py is in python3-gitdb 2.0.0-2.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 | # Copyright (C) 2010, 2011 Sebastian Thiel (byronimo@gmail.com) and contributors
#
# This module is part of GitDB and is released under
# the New BSD License: http://www.opensource.org/licenses/bsd-license.php
"""Module containing a database to deal with packs"""
from gitdb.db.base import (
FileDBBase,
ObjectDBR,
CachingDB
)
from gitdb.util import LazyMixin
from gitdb.exc import (
BadObject,
UnsupportedOperation,
AmbiguousObjectName
)
from gitdb.pack import PackEntity
from gitdb.utils.compat import xrange
from functools import reduce
import os
import glob
__all__ = ('PackedDB', )
#{ Utilities
class PackedDB(FileDBBase, ObjectDBR, CachingDB, LazyMixin):
"""A database operating on a set of object packs"""
# sort the priority list every N queries
# Higher values are better, performance tests don't show this has
# any effect, but it should have one
_sort_interval = 500
def __init__(self, root_path):
super(PackedDB, self).__init__(root_path)
# list of lists with three items:
# * hits - number of times the pack was hit with a request
# * entity - Pack entity instance
# * sha_to_index - PackIndexFile.sha_to_index method for direct cache query
# self._entities = list() # lazy loaded list
self._hit_count = 0 # amount of hits
self._st_mtime = 0 # last modification data of our root path
def _set_cache_(self, attr):
if attr == '_entities':
self._entities = list()
self.update_cache(force=True)
# END handle entities initialization
def _sort_entities(self):
self._entities.sort(key=lambda l: l[0], reverse=True)
def _pack_info(self, sha):
""":return: tuple(entity, index) for an item at the given sha
:param sha: 20 or 40 byte sha
:raise BadObject:
**Note:** This method is not thread-safe, but may be hit in multi-threaded
operation. The worst thing that can happen though is a counter that
was not incremented, or the list being in wrong order. So we safe
the time for locking here, lets see how that goes"""
# presort ?
if self._hit_count % self._sort_interval == 0:
self._sort_entities()
# END update sorting
for item in self._entities:
index = item[2](sha)
if index is not None:
item[0] += 1 # one hit for you
self._hit_count += 1 # general hit count
return (item[1], index)
# END index found in pack
# END for each item
# no hit, see whether we have to update packs
# NOTE: considering packs don't change very often, we safe this call
# and leave it to the super-caller to trigger that
raise BadObject(sha)
#{ Object DB Read
def has_object(self, sha):
try:
self._pack_info(sha)
return True
except BadObject:
return False
# END exception handling
def info(self, sha):
entity, index = self._pack_info(sha)
return entity.info_at_index(index)
def stream(self, sha):
entity, index = self._pack_info(sha)
return entity.stream_at_index(index)
def sha_iter(self):
for entity in self.entities():
index = entity.index()
sha_by_index = index.sha
for index in xrange(index.size()):
yield sha_by_index(index)
# END for each index
# END for each entity
def size(self):
sizes = [item[1].index().size() for item in self._entities]
return reduce(lambda x, y: x + y, sizes, 0)
#} END object db read
#{ object db write
def store(self, istream):
"""Storing individual objects is not feasible as a pack is designed to
hold multiple objects. Writing or rewriting packs for single objects is
inefficient"""
raise UnsupportedOperation()
#} END object db write
#{ Interface
def update_cache(self, force=False):
"""
Update our cache with the acutally existing packs on disk. Add new ones,
and remove deleted ones. We keep the unchanged ones
:param force: If True, the cache will be updated even though the directory
does not appear to have changed according to its modification timestamp.
:return: True if the packs have been updated so there is new information,
False if there was no change to the pack database"""
stat = os.stat(self.root_path())
if not force and stat.st_mtime <= self._st_mtime:
return False
# END abort early on no change
self._st_mtime = stat.st_mtime
# packs are supposed to be prefixed with pack- by git-convention
# get all pack files, figure out what changed
pack_files = set(glob.glob(os.path.join(self.root_path(), "pack-*.pack")))
our_pack_files = set(item[1].pack().path() for item in self._entities)
# new packs
for pack_file in (pack_files - our_pack_files):
# init the hit-counter/priority with the size, a good measure for hit-
# probability. Its implemented so that only 12 bytes will be read
entity = PackEntity(pack_file)
self._entities.append([entity.pack().size(), entity, entity.index().sha_to_index])
# END for each new packfile
# removed packs
for pack_file in (our_pack_files - pack_files):
del_index = -1
for i, item in enumerate(self._entities):
if item[1].pack().path() == pack_file:
del_index = i
break
# END found index
# END for each entity
assert del_index != -1
del(self._entities[del_index])
# END for each removed pack
# reinitialize prioritiess
self._sort_entities()
return True
def entities(self):
""":return: list of pack entities operated upon by this database"""
return [item[1] for item in self._entities]
def partial_to_complete_sha(self, partial_binsha, canonical_length):
""":return: 20 byte sha as inferred by the given partial binary sha
:param partial_binsha: binary sha with less than 20 bytes
:param canonical_length: length of the corresponding canonical representation.
It is required as binary sha's cannot display whether the original hex sha
had an odd or even number of characters
:raise AmbiguousObjectName:
:raise BadObject: """
candidate = None
for item in self._entities:
item_index = item[1].index().partial_sha_to_index(partial_binsha, canonical_length)
if item_index is not None:
sha = item[1].index().sha(item_index)
if candidate and candidate != sha:
raise AmbiguousObjectName(partial_binsha)
candidate = sha
# END handle full sha could be found
# END for each entity
if candidate:
return candidate
# still not found ?
raise BadObject(partial_binsha)
#} END interface
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