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1# Copyright 2017 The Chromium OS Authors. All rights reserved.
2# Use of this source code is governed by a BSD-style license that can be
3# found in the LICENSE file.
4
5"""This module provides standard functions for working with Autotest labels.
6
7There are two types of labels, plain ("webcam") or keyval
8("pool:suites").  Most of this module's functions work with keyval
9labels.
10
11Most users should use LabelsMapping, which provides a dict-like
12interface for working with keyval labels.
13
14This module also provides functions for working with cros version
15strings, which are common keyval label values.
16"""
17
18import collections
19import re
20
21
22class Key(object):
23    """Enum for keyval label keys."""
24    CROS_VERSION = 'cros-version'
25    CROS_ANDROID_VERSION = 'cheets-version'
26    FIRMWARE_RW_VERSION = 'fwrw-version'
27    FIRMWARE_RO_VERSION = 'fwro-version'
28
29
30class LabelsMapping(collections.MutableMapping):
31    """dict-like interface for working with labels.
32
33    The constructor takes an iterable of labels, either plain or keyval.
34    Plain labels are saved internally and ignored except for converting
35    back to string labels.  Keyval labels are exposed through a
36    dict-like interface (pop(), keys(), items(), etc. are all
37    supported).
38
39    When multiple keyval labels share the same key, the first one wins.
40
41    The one difference from a dict is that setting a key to None will
42    delete the corresponding keyval label, since it does not make sense
43    for a keyval label to have a None value.  Prefer using del or pop()
44    instead of setting a key to None.
45
46    LabelsMapping has one method getlabels() for converting back to
47    string labels.
48    """
49
50    def __init__(self, str_labels=()):
51        self._plain_labels = []
52        self._keyval_map = collections.OrderedDict()
53        for str_label in str_labels:
54            self._add_label(str_label)
55
56    @classmethod
57    def from_host(cls, host):
58        """Create instance using a frontend.afe.models.Host object."""
59        return cls(l.name for l in host.labels.all())
60
61    def _add_label(self, str_label):
62        """Add a label string to the internal map or plain labels list."""
63        try:
64            keyval_label = parse_keyval_label(str_label)
65        except ValueError:
66            self._plain_labels.append(str_label)
67        else:
68            if keyval_label.key not in self._keyval_map:
69                self._keyval_map[keyval_label.key] = keyval_label.value
70
71    def __getitem__(self, key):
72        return self._keyval_map[key]
73
74    def __setitem__(self, key, val):
75        if val is None:
76            self.pop(key, None)
77        else:
78            self._keyval_map[key] = val
79
80    def __delitem__(self, key):
81        del self._keyval_map[key]
82
83    def __iter__(self):
84        return iter(self._keyval_map)
85
86    def __len__(self):
87        return len(self._keyval_map)
88
89    def getlabels(self):
90        """Return labels as a list of strings."""
91        str_labels = self._plain_labels[:]
92        keyval_labels = (KeyvalLabel(key, value)
93                         for key, value in self.iteritems())
94        str_labels.extend(format_keyval_label(label)
95                          for label in keyval_labels)
96        return str_labels
97
98
99_KEYVAL_LABEL_SEP = ':'
100
101
102KeyvalLabel = collections.namedtuple('KeyvalLabel', 'key, value')
103
104
105def parse_keyval_label(str_label):
106    """Parse a string as a KeyvalLabel.
107
108    If the argument is not a valid keyval label, ValueError is raised.
109    """
110    key, value = str_label.split(_KEYVAL_LABEL_SEP, 1)
111    return KeyvalLabel(key, value)
112
113
114def format_keyval_label(keyval_label):
115    """Format a KeyvalLabel as a string."""
116    return _KEYVAL_LABEL_SEP.join(keyval_label)
117
118
119CrosVersion = collections.namedtuple(
120        'CrosVersion', 'group, board, milestone, version, rc')
121
122
123_CROS_VERSION_REGEX = (
124        r'^'
125        r'(?P<group>[a-z0-9_-]+)'
126        r'/'
127        r'(?P<milestone>R[0-9]+)'
128        r'-'
129        r'(?P<version>[0-9.]+)'
130        r'(-(?P<rc>rc[0-9]+))?'
131        r'$'
132)
133
134_CROS_BOARD_FROM_VERSION_REGEX = (
135        r'^'
136        r'(trybot-)?'
137        r'(?P<board>[a-z_-]+)-(release|paladin|pre-cq|test-ap|toolchain)'
138        r'/R.*'
139        r'$'
140)
141
142
143def parse_cros_version(version_string):
144    """Parse a string as a CrosVersion.
145
146    If the argument is not a valid cros version, ValueError is raised.
147    Example cros version string: 'lumpy-release/R27-3773.0.0-rc1'
148    """
149    match = re.search(_CROS_VERSION_REGEX, version_string)
150    if match is None:
151        raise ValueError('Invalid cros version string: %r' % version_string)
152    parts = match.groupdict()
153    match = re.search(_CROS_BOARD_FROM_VERSION_REGEX, version_string)
154    if match is None:
155        raise ValueError('Invalid cros version string: %r. Failed to parse '
156                         'board.' % version_string)
157    parts['board'] = match.group('board')
158    return CrosVersion(**parts)
159
160
161def format_cros_version(cros_version):
162    """Format a CrosVersion as a string."""
163    if cros_version.rc is not None:
164        return '{group}/{milestone}-{version}-{rc}'.format(
165                **cros_version._asdict())
166    else:
167        return '{group}/{milestone}-{version}'.format(**cros_version._asdict())
168