summaryrefslogtreecommitdiffstats
path: root/scripts/python-lib/yaml/resolver.py
blob: 6b5ab87596edf7ec15d523cead7a474fdea6bdc7 (plain)
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
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
__all__ = ['BaseResolver', 'Resolver']

from error import *
from nodes import *

import re

class ResolverError(YAMLError):
    pass

class BaseResolver(object):

    DEFAULT_SCALAR_TAG = u'tag:yaml.org,2002:str'
    DEFAULT_SEQUENCE_TAG = u'tag:yaml.org,2002:seq'
    DEFAULT_MAPPING_TAG = u'tag:yaml.org,2002:map'

    yaml_implicit_resolvers = {}
    yaml_path_resolvers = {}

    def __init__(self):
        self.resolver_exact_paths = []
        self.resolver_prefix_paths = []

    def add_implicit_resolver(cls, tag, regexp, first):
        if not 'yaml_implicit_resolvers' in cls.__dict__:
            cls.yaml_implicit_resolvers = cls.yaml_implicit_resolvers.copy()
        if first is None:
            first = [None]
        for ch in first:
            cls.yaml_implicit_resolvers.setdefault(ch, []).append((tag, regexp))
    add_implicit_resolver = classmethod(add_implicit_resolver)

    def add_path_resolver(cls, tag, path, kind=None):
        # Note: `add_path_resolver` is experimental.  The API could be changed.
        # `new_path` is a pattern that is matched against the path from the
        # root to the node that is being considered.  `node_path` elements are
        # tuples `(node_check, index_check)`.  `node_check` is a node class:
        # `ScalarNode`, `SequenceNode`, `MappingNode` or `None`.  `None`
        # matches any kind of a node.  `index_check` could be `None`, a boolean
        # value, a string value, or a number.  `None` and `False` match against
        # any _value_ of sequence and mapping nodes.  `True` matches against
        # any _key_ of a mapping node.  A string `index_check` matches against
        # a mapping value that corresponds to a scalar key which content is
        # equal to the `index_check` value.  An integer `index_check` matches
        # against a sequence value with the index equal to `index_check`.
        if not 'yaml_path_resolvers' in cls.__dict__:
            cls.yaml_path_resolvers = cls.yaml_path_resolvers.copy()
        new_path = []
        for element in path:
            if isinstance(element, (list, tuple)):
                if len(element) == 2:
                    node_check, index_check = element
                elif len(element) == 1:
                    node_check = element[0]
                    index_check = True
                else:
                    raise ResolverError("Invalid path element: %s" % element)
            else:
                node_check = None
                index_check = element
            if node_check is str:
                node_check = ScalarNode
            elif node_check is list:
                node_check = SequenceNode
            elif node_check is dict:
                node_check = MappingNode
            elif node_check not in [ScalarNode, SequenceNode, MappingNode]  \
                    and not isinstance(node_check, basestring)  \
                    and node_check is not None:
                raise ResolverError("Invalid node checker: %s" % node_check)
            if not isinstance(index_check, (basestring, int))   \
                    and index_check is not None:
                raise ResolverError("Invalid index checker: %s" % index_check)
            new_path.append((node_check, index_check))
        if kind is str:
            kind = ScalarNode
        elif kind is list:
            kind = SequenceNode
        elif kind is dict:
            kind = MappingNode
        elif kind not in [ScalarNode, SequenceNode, MappingNode]    \
                and kind is not None:
            raise ResolverError("Invalid node kind: %s" % kind)
        cls.yaml_path_resolvers[tuple(new_path), kind] = tag
    add_path_resolver = classmethod(add_path_resolver)

    def descend_resolver(self, current_node, current_index):
        if not self.yaml_path_resolvers:
            return
        exact_paths = {}
        prefix_paths = []
        if current_node:
            depth = len(self.resolver_prefix_paths)
            for path, kind in self.resolver_prefix_paths[-1]:
                if self.check_resolver_prefix(depth, path, kind,
                        current_node, current_index):
                    if len(path) > depth:
                        prefix_paths.append((path, kind))
                    else:
                        exact_paths[kind] = self.yaml_path_resolvers[path, kind]
        else:
            for path, kind in self.yaml_path_resolvers:
                if not path:
                    exact_paths[kind] = self.yaml_path_resolvers[path, kind]
                else:
                    prefix_paths.append((path, kind))
        self.resolver_exact_paths.append(exact_paths)
        self.resolver_prefix_paths.append(prefix_paths)

    def ascend_resolver(self):
        if not self.yaml_path_resolvers:
            return
        self.resolver_exact_paths.pop()
        self.resolver_prefix_paths.pop()

    def check_resolver_prefix(self, depth, path, kind,
            current_node, current_index):
        node_check, index_check = path[depth-1]
        if isinstance(node_check, basestring):
            if current_node.tag != node_check:
                return
        elif node_check is not None:
            if not isinstance(current_node, node_check):
                return
        if index_check is True and current_index is not None:
            return
        if (index_check is False or index_check is None)    \
                and current_index is None:
            return
        if isinstance(index_check, basestring):
            if not (isinstance(current_index, ScalarNode)
                    and index_check == current_index.value):
                return
        elif isinstance(index_check, int) and not isinstance(index_check, bool):
            if index_check != current_index:
                return
        return True

    def resolve(self, kind, value, implicit):
        if kind is ScalarNode and implicit[0]:
            if value == u'':
                resolvers = self.yaml_implicit_resolvers.get(u'', [])
            else:
                resolvers = self.yaml_implicit_resolvers.get(value[0], [])
            resolvers += self.yaml_implicit_resolvers.get(None, [])
            for tag, regexp in resolvers:
                if regexp.match(value):
                    return tag
            implicit = implicit[1]
        if self.yaml_path_resolvers:
            exact_paths = self.resolver_exact_paths[-1]
            if kind in exact_paths:
                return exact_paths[kind]
            if None in exact_paths:
                return exact_paths[None]
        if kind is ScalarNode:
            return self.DEFAULT_SCALAR_TAG
        elif kind is SequenceNode:
            return self.DEFAULT_SEQUENCE_TAG
        elif kind is MappingNode:
            return self.DEFAULT_MAPPING_TAG

class Resolver(BaseResolver):
    pass

Resolver.add_implicit_resolver(
        u'tag:yaml.org,2002:bool',
        re.compile(ur'''^(?:yes|Yes|YES|no|No|NO
                    |true|True|TRUE|false|False|FALSE
                    |on|On|ON|off|Off|OFF)$''', re.X),
        list(u'yYnNtTfFoO'))

Resolver.add_implicit_resolver(
        u'tag:yaml.org,2002:float',
        re.compile(ur'''^(?:[-+]?(?:[0-9][0-9_]*)\.[0-9_]*(?:[eE][-+][0-9]+)?
                    |\.[0-9_]+(?:[eE][-+][0-9]+)?
                    |[-+]?[0-9][0-9_]*(?::[0-5]?[0-9])+\.[0-9_]*
                    |[-+]?\.(?:inf|Inf|INF)
                    |\.(?:nan|NaN|NAN))$''', re.X),
        list(u'-+0123456789.'))

Resolver.add_implicit_resolver(
        u'tag:yaml.org,2002:int',
        re.compile(ur'''^(?:[-+]?0b[0-1_]+
                    |[-+]?0[0-7_]+
                    |[-+]?(?:0|[1-9][0-9_]*)
                    |[-+]?0x[0-9a-fA-F_]+
                    |[-+]?[1-9][0-9_]*(?::[0-5]?[0-9])+)$''', re.X),
        list(u'-+0123456789'))

Resolver.add_implicit_resolver(
        u'tag:yaml.org,2002:merge',
        re.compile(ur'^(?:<<)$'),
        [u'<'])

Resolver.add_implicit_resolver(
        u'tag:yaml.org,2002:null',
        re.compile(ur'''^(?: ~
                    |null|Null|NULL
                    | )$''', re.X),
        [u'~', u'n', u'N', u''])

Resolver.add_implicit_resolver(
        u'tag:yaml.org,2002:timestamp',
        re.compile(ur'''^(?:[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]
                    |[0-9][0-9][0-9][0-9] -[0-9][0-9]? -[0-9][0-9]?
                     (?:[Tt]|[ \t]+)[0-9][0-9]?
                     :[0-9][0-9] :[0-9][0-9] (?:\.[0-9]*)?
                     (?:[ \t]*(?:Z|[-+][0-9][0-9]?(?::[0-9][0-9])?))?)$''', re.X),
        list(u'0123456789'))

Resolver.add_implicit_resolver(
        u'tag:yaml.org,2002:value',
        re.compile(ur'^(?:=)$'),
        [u'='])

# The following resolver is only for documentation purposes. It cannot work
# because plain scalars cannot start with '!', '&', or '*'.
Resolver.add_implicit_resolver(
        u'tag:yaml.org,2002:yaml',
        re.compile(ur'^(?:!|&|\*)$'),
        list(u'!&*'))