# Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Modules for obtaining Chrome OS release info."""
import ConfigParser
import bisect
import os
_RELEASE_CONFIG_FILE = os.path.join(os.path.dirname(__file__),
'release_config.ini')
# Prefix for brachpoint definitions in the config file.
_CONF_BRANCH_SECTION = 'BRANCH'
_CONF_BRANCH_POINTS_OPT = 'branch_points'
_CONF_BRANCH_POINT_OPT_PREFIX = 'bp_'
_CONF_NEXT_BRANCH_OPT = 'next_branch'
class ReleaseError(BaseException):
"""Errors related to release and branch inference."""
pass
class ReleaseInfo(object):
"""Provides reference information about Chrome OS releases.
Currently, this class serves for mapping between releases and branches /
release milestones. The information lives in a .ini file at the current
directory, which has a single section [BRANCH] containing
branch_points: comma-separated list of release branches (e.g. R10, R11,
...)
bp_XYZ: for each branch listed above, a variable that maps to the Chrome
OS release at that branchpoint (e.g. bp_r10: 0.10.156.0). Note that .ini
file variables are case-insensitive.
next_branch: the name of the current (unforked) branch (e.g. R24)
It is also worth noting that a branch point X.Y.Z (alternatively, W.X.Y.Z)
of some branch R denotes the build number X (repsectively, W) that
constitutes the said branch. Therefore, it is only from build X+1 (W+1) and
onward that releases will be tagged with R+1.
"""
def __init__(self):
self._release_config = None
self._branchpoint_dict = None
self._next_branch = None
self._sorted_branchpoint_list = None
self._sorted_shifted_branchpoint_rel_key_list = None
def initialize(self):
"""Read release config and initialize lookup data structures."""
self._release_config = ConfigParser.ConfigParser()
try:
self._release_config.readfp(open(_RELEASE_CONFIG_FILE))
# Build branchpoint dictionary.
branchpoint_list_str = self._release_config.get(
_CONF_BRANCH_SECTION, _CONF_BRANCH_POINTS_OPT)
if branchpoint_list_str:
branchpoint_list = map(str.strip,
branchpoint_list_str.split(','))
else:
branchpoint_list = []
self._branchpoint_dict = {}
for branchpoint in branchpoint_list:
self._branchpoint_dict[branchpoint] = (
self._release_config.get(
_CONF_BRANCH_SECTION,
_CONF_BRANCH_POINT_OPT_PREFIX + branchpoint))
# Get next branch name.
self._next_branch = self._release_config.get(_CONF_BRANCH_SECTION,
_CONF_NEXT_BRANCH_OPT)
if not self._next_branch:
raise ReleaseError("missing `%s' option" %
_CONF_NEXT_BRANCH_OPT)
except IOError, e:
raise ReleaseError('failed to open release config file (%s): %s' %
(_RELEASE_CONFIG_FILE, e))
except ConfigParser.Error, e:
raise ReleaseError('failed to load release config: %s' % e)
# Infer chronologically sorted list of branchpoints.
self._sorted_branchpoint_list = self._branchpoint_dict.items()
self._sorted_branchpoint_list.append((self._next_branch, '99999.0.0'))
self._sorted_branchpoint_list.sort(
key=lambda (branch, release): self._release_key(release))
# Also store a sorted list of branchpoint release keys, for easy lookup.
self._sorted_shifted_branchpoint_rel_key_list = [
self._release_key(self._next_build_number_release(release))
for (branch, release) in self._sorted_branchpoint_list]
def _next_build_number_release(self, release):
"""Returns the release of the next build following a given release.
Given a release number 'X.Y.Z' (new scheme) or '0.X.Y.Z' (old scheme)
it will return 'X+1.0.0' or '0.X+1.0.0', respectively.
@param release: the release number in dotted notation (string)
@return The release number of the next build.
@raise ReleaseError if the release is malformed.
"""
release_components = release.split('.')
if len(release_components) == 4 and release_components[0] == '0':
prepend = '0.'
x = int(release_components[1])
elif len(release_components) != 3:
raise ReleaseError('invalid release number: %s' % release)
else:
prepend = ''
x = int(release_components[0])
return '%s%s.0.0' % (prepend, x + 1)
def _release_key(self, release):
"""Convert a Chrome OS release string into an integer key.
This translates a release string 'X.Y.Z' (new scheme) or 'W.X.Y.Z' (old
scheme where W = 0) into an integer whose value equals X * 10^7 + Y *
10^3 + Z, assuming that Y < 10^4 and Z < 10^3, and will scale safely to
any foreseeable major release number (X).
@param release: the release number in dotted notation (string)
@return A unique integer key representing the release.
@raise ReleaseError if the release is malformed.
"""
release_components = release.split('.')
if len(release_components) == 4 and release_components[0] == '0':
release_components = release_components[1:]
elif len(release_components) != 3:
raise ReleaseError('invalid release number: %s' % release)
x, y, z = [int(s) for s in release_components]
return x * 10000000 + y * 1000 + z
def get_branch_list(self):
"""Retruns chronologically sorted list of branch names."""
return [branch for (branch, release) in self._sorted_branchpoint_list]
def get_branch(self, release):
"""Returns the branch name of a given release version. """
i = bisect.bisect_left(self._sorted_shifted_branchpoint_rel_key_list,
self._release_key(release))
return self._sorted_branchpoint_list[i][0] if i else None
def get_branchpoint_release(self, branch):
"""Returns the branchpoint release of a given branch.
Returns None if given name is the next branch.
@raise KeyError if branch name not known
"""
if branch == self._next_branch:
return None
return self._branchpoint_dict[branch]