/
parser.py
237 lines (199 loc) · 6.38 KB
/
parser.py
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
225
226
227
228
229
230
231
232
233
234
235
236
237
import codecs
import re
from .compat import IS_TYPE_CHECKING, to_text
if IS_TYPE_CHECKING:
from typing import ( # noqa:F401
IO, Iterator, Match, NamedTuple, Optional, Pattern, Sequence, Text,
Tuple
)
def make_regex(string, extra_flags=0):
# type: (str, int) -> Pattern[Text]
return re.compile(to_text(string), re.UNICODE | extra_flags)
_newline = make_regex(r"(\r\n|\n|\r)")
_multiline_whitespace = make_regex(r"\s*", extra_flags=re.MULTILINE)
_whitespace = make_regex(r"[^\S\r\n]*")
_export = make_regex(r"(?:export[^\S\r\n]+)?")
_single_quoted_key = make_regex(r"'([^']+)'")
_unquoted_key = make_regex(r"([^=\#\s]+)")
_equal_sign = make_regex(r"(=[^\S\r\n]*)")
_single_quoted_value = make_regex(r"'((?:\\'|[^'])*)'")
_double_quoted_value = make_regex(r'"((?:\\"|[^"])*)"')
_unquoted_value_part = make_regex(r"(\S*)")
_comment = make_regex(r"(?:[^\S\r\n]*#[^\r\n]*)?")
_end_of_line = make_regex(r"[^\S\r\n]*(?:\r\n|\n|\r|$)")
_rest_of_line = make_regex(r"[^\r\n]*(?:\r|\n|\r\n)?")
_double_quote_escapes = make_regex(r"\\[\\'\"abfnrtv]")
_single_quote_escapes = make_regex(r"\\[\\']")
try:
# this is necessary because we only import these from typing
# when we are type checking, and the linter is upset if we
# re-import
import typing
Original = typing.NamedTuple(
"Original",
[
("string", typing.Text),
("line", int),
],
)
Binding = typing.NamedTuple(
"Binding",
[
("key", typing.Optional[typing.Text]),
("value", typing.Optional[typing.Text]),
("original", Original),
("error", bool),
],
)
except ImportError:
from collections import namedtuple
Original = namedtuple( # type: ignore
"Original",
[
"string",
"line",
],
)
Binding = namedtuple( # type: ignore
"Binding",
[
"key",
"value",
"original",
"error",
],
)
class Position:
def __init__(self, chars, line):
# type: (int, int) -> None
self.chars = chars
self.line = line
@classmethod
def start(cls):
# type: () -> Position
return cls(chars=0, line=1)
def set(self, other):
# type: (Position) -> None
self.chars = other.chars
self.line = other.line
def advance(self, string):
# type: (Text) -> None
self.chars += len(string)
self.line += len(re.findall(_newline, string))
class Error(Exception):
pass
class Reader:
def __init__(self, stream):
# type: (IO[Text]) -> None
self.string = stream.read()
self.position = Position.start()
self.mark = Position.start()
def has_next(self):
# type: () -> bool
return self.position.chars < len(self.string)
def set_mark(self):
# type: () -> None
self.mark.set(self.position)
def get_marked(self):
# type: () -> Original
return Original(
string=self.string[self.mark.chars:self.position.chars],
line=self.mark.line,
)
def peek(self, count):
# type: (int) -> Text
return self.string[self.position.chars:self.position.chars + count]
def read(self, count):
# type: (int) -> Text
result = self.string[self.position.chars:self.position.chars + count]
if len(result) < count:
raise Error("read: End of string")
self.position.advance(result)
return result
def read_regex(self, regex):
# type: (Pattern[Text]) -> Sequence[Text]
match = regex.match(self.string, self.position.chars)
if match is None:
raise Error("read_regex: Pattern not found")
self.position.advance(self.string[match.start():match.end()])
return match.groups()
def decode_escapes(regex, string):
# type: (Pattern[Text], Text) -> Text
def decode_match(match):
# type: (Match[Text]) -> Text
return codecs.decode(match.group(0), 'unicode-escape') # type: ignore
return regex.sub(decode_match, string)
def parse_key(reader):
# type: (Reader) -> Optional[Text]
char = reader.peek(1)
if char == "#":
return None
elif char == "'":
(key,) = reader.read_regex(_single_quoted_key)
else:
(key,) = reader.read_regex(_unquoted_key)
return key
def parse_unquoted_value(reader):
# type: (Reader) -> Text
value = u""
while True:
(part,) = reader.read_regex(_unquoted_value_part)
value += part
after = reader.peek(2)
if after[:1] not in (u" ", u"\t") or after in (u" #", u"\t#"):
return value.rstrip()
value += reader.read(1)
def parse_value(reader):
# type: (Reader) -> Text
char = reader.peek(1)
if char == u"'":
(value,) = reader.read_regex(_single_quoted_value)
return decode_escapes(_single_quote_escapes, value)
elif char == u'"':
(value,) = reader.read_regex(_double_quoted_value)
return decode_escapes(_double_quote_escapes, value)
elif char in (u"", u"\n", u"\r"):
return u""
else:
return parse_unquoted_value(reader)
def parse_binding(reader):
# type: (Reader) -> Binding
reader.set_mark()
try:
reader.read_regex(_multiline_whitespace)
if not reader.has_next():
return Binding(
key=None,
value=None,
original=reader.get_marked(),
error=False,
)
reader.read_regex(_export)
key = parse_key(reader)
reader.read_regex(_whitespace)
if reader.peek(1) == "=":
reader.read_regex(_equal_sign)
value = parse_value(reader) # type: Optional[Text]
else:
value = None
reader.read_regex(_comment)
reader.read_regex(_end_of_line)
return Binding(
key=key,
value=value,
original=reader.get_marked(),
error=False,
)
except Error:
reader.read_regex(_rest_of_line)
return Binding(
key=None,
value=None,
original=reader.get_marked(),
error=True,
)
def parse_stream(stream):
# type: (IO[Text]) -> Iterator[Binding]
reader = Reader(stream)
while reader.has_next():
yield parse_binding(reader)