You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
189 lines
6.7 KiB
189 lines
6.7 KiB
# 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, sys
|
|
|
|
has_ucs4 = sys.maxunicode > 0xffff
|
|
|
|
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, str):
|
|
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 unicode,
|
|
# - checks if characters are in allowed range,
|
|
# - adds '\0' to the end.
|
|
|
|
# Reader accepts
|
|
# - a `str` object,
|
|
# - a `unicode` 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 = u''
|
|
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, unicode):
|
|
self.name = "<unicode string>"
|
|
self.check_printable(stream)
|
|
self.buffer = stream+u'\0'
|
|
elif isinstance(stream, str):
|
|
self.name = "<string>"
|
|
self.raw_buffer = stream
|
|
self.determine_encoding()
|
|
else:
|
|
self.stream = stream
|
|
self.name = getattr(stream, 'name', "<file>")
|
|
self.eof = False
|
|
self.raw_buffer = ''
|
|
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 u'\n\x85\u2028\u2029' \
|
|
or (ch == u'\r' and self.buffer[self.pointer] != u'\n'):
|
|
self.line += 1
|
|
self.column = 0
|
|
elif ch != u'\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 len(self.raw_buffer) < 2:
|
|
self.update_raw()
|
|
if not isinstance(self.raw_buffer, unicode):
|
|
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)
|
|
|
|
if has_ucs4:
|
|
NON_PRINTABLE = re.compile(u'[^\x09\x0A\x0D\x20-\x7E\x85\xA0-\uD7FF\uE000-\uFFFD\U00010000-\U0010ffff]')
|
|
else:
|
|
NON_PRINTABLE = re.compile(u'[^\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, exc:
|
|
character = exc.object[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 += u'\0'
|
|
self.raw_buffer = None
|
|
break
|
|
|
|
def update_raw(self, size=1024):
|
|
data = self.stream.read(size)
|
|
if data:
|
|
self.raw_buffer += data
|
|
self.stream_pointer += len(data)
|
|
else:
|
|
self.eof = True
|