summaryrefslogtreecommitdiffstats
path: root/python.d/python_modules/pyyaml3/reader.py
blob: f70e920f44195f22e9f47b7ea1e5c90c3fce06cf (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
# This module contains abstractions for the input stream. You don't have to
# looks further, there are no pretty code.
#
# We define two classes here.
#
#   Mark(source, line, column)
# It's just a record and its only use is producing nice error messages.
# Parser does not use it for any other purposes.
#
#   Reader(source, data)
# Reader determines the encoding of `data` and converts it to unicode.
# Reader provides the following methods and attributes:
#   reader.peek(length=1) - return the next `length` characters
#   reader.forward(length=1) - move the current position to `length` characters.
#   reader.index - the number of the current character.
#   reader.line, stream.column - the line and the column of the current character.

__all__ = ['Reader', 'ReaderError']

from .error import YAMLError, Mark

import codecs, re

class ReaderError(YAMLError):

    def __init__(self, name, position, character, encoding, reason):
        self.name = name
        self.character = character
        self.position = position
        self.encoding = encoding
        self.reason = reason

    def __str__(self):
        if isinstance(self.character, bytes):
            return "'%s' codec can't decode byte #x%02x: %s\n"  \
                    "  in \"%s\", position %d"    \
                    % (self.encoding, ord(self.character), self.reason,
                            self.name, self.position)
        else:
            return "unacceptable character #x%04x: %s\n"    \
                    "  in \"%s\", position %d"    \
                    % (self.character, self.reason,
                            self.name, self.position)

class Reader(object):
    # Reader:
    # - determines the data encoding and converts it to a unicode string,
    # - checks if characters are in allowed range,
    # - adds '\0' to the end.

    # Reader accepts
    #  - a `bytes` object,
    #  - a `str` object,
    #  - a file-like object with its `read` method returning `str`,
    #  - a file-like object with its `read` method returning `unicode`.

    # Yeah, it's ugly and slow.

    def __init__(self, stream):
        self.name = None
        self.stream = None
        self.stream_pointer = 0
        self.eof = True
        self.buffer = ''
        self.pointer = 0
        self.raw_buffer = None
        self.raw_decode = None
        self.encoding = None
        self.index = 0
        self.line = 0
        self.column = 0
        if isinstance(stream, str):
            self.name = "<unicode string>"
            self.check_printable(stream)
            self.buffer = stream+'\0'
        elif isinstance(stream, bytes):
            self.name = "<byte string>"
            self.raw_buffer = stream
            self.determine_encoding()
        else:
            self.stream = stream
            self.name = getattr(stream, 'name', "<file>")
            self.eof = False
            self.raw_buffer = None
            self.determine_encoding()

    def peek(self, index=0):
        try:
            return self.buffer[self.pointer+index]
        except IndexError:
            self.update(index+1)
            return self.buffer[self.pointer+index]

    def prefix(self, length=1):
        if self.pointer+length >= len(self.buffer):
            self.update(length)
        return self.buffer[self.pointer:self.pointer+length]

    def forward(self, length=1):
        if self.pointer+length+1 >= len(self.buffer):
            self.update(length+1)
        while length:
            ch = self.buffer[self.pointer]
            self.pointer += 1
            self.index += 1
            if ch in '\n\x85\u2028\u2029'  \
                    or (ch == '\r' and self.buffer[self.pointer] != '\n'):
                self.line += 1
                self.column = 0
            elif ch != '\uFEFF':
                self.column += 1
            length -= 1

    def get_mark(self):
        if self.stream is None:
            return Mark(self.name, self.index, self.line, self.column,
                    self.buffer, self.pointer)
        else:
            return Mark(self.name, self.index, self.line, self.column,
                    None, None)

    def determine_encoding(self):
        while not self.eof and (self.raw_buffer is None or len(self.raw_buffer) < 2):
            self.update_raw()
        if isinstance(self.raw_buffer, bytes):
            if self.raw_buffer.startswith(codecs.BOM_UTF16_LE):
                self.raw_decode = codecs.utf_16_le_decode
                self.encoding = 'utf-16-le'
            elif self.raw_buffer.startswith(codecs.BOM_UTF16_BE):
                self.raw_decode = codecs.utf_16_be_decode
                self.encoding = 'utf-16-be'
            else:
                self.raw_decode = codecs.utf_8_decode
                self.encoding = 'utf-8'
        self.update(1)

    NON_PRINTABLE = re.compile('[^\x09\x0A\x0D\x20-\x7E\x85\xA0-\uD7FF\uE000-\uFFFD]')
    def check_printable(self, data):
        match = self.NON_PRINTABLE.search(data)
        if match:
            character = match.group()
            position = self.index+(len(self.buffer)-self.pointer)+match.start()
            raise ReaderError(self.name, position, ord(character),
                    'unicode', "special characters are not allowed")

    def update(self, length):
        if self.raw_buffer is None:
            return
        self.buffer = self.buffer[self.pointer:]
        self.pointer = 0
        while len(self.buffer) < length:
            if not self.eof:
                self.update_raw()
            if self.raw_decode is not None:
                try:
                    data, converted = self.raw_decode(self.raw_buffer,
                            'strict', self.eof)
                except UnicodeDecodeError as exc:
                    character = self.raw_buffer[exc.start]
                    if self.stream is not None:
                        position = self.stream_pointer-len(self.raw_buffer)+exc.start
                    else:
                        position = exc.start
                    raise ReaderError(self.name, position, character,
                            exc.encoding, exc.reason)
            else:
                data = self.raw_buffer
                converted = len(data)
            self.check_printable(data)
            self.buffer += data
            self.raw_buffer = self.raw_buffer[converted:]
            if self.eof:
                self.buffer += '\0'
                self.raw_buffer = None
                break

    def update_raw(self, size=4096):
        data = self.stream.read(size)
        if self.raw_buffer is None:
            self.raw_buffer = data
        else:
            self.raw_buffer += data
        self.stream_pointer += len(data)
        if not data:
            self.eof = True

#try:
#    import psyco
#    psyco.bind(Reader)
#except ImportError:
#    pass