| # 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. |
| # |
| # Marker(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, Marker |
| |
| import codecs, re |
| |
| # Unfortunately, codec functions in Python 2.3 does not support the `finish` |
| # arguments, so we have to write our own wrappers. |
| |
| try: |
| codecs.utf_8_decode('', 'strict', False) |
| from codecs import utf_8_decode, utf_16_le_decode, utf_16_be_decode |
| |
| except TypeError: |
| |
| def utf_16_le_decode(data, errors, finish=False): |
| if not finish and len(data) % 2 == 1: |
| data = data[:-1] |
| return codecs.utf_16_le_decode(data, errors) |
| |
| def utf_16_be_decode(data, errors, finish=False): |
| if not finish and len(data) % 2 == 1: |
| data = data[:-1] |
| return codecs.utf_16_be_decode(data, errors) |
| |
| def utf_8_decode(data, errors, finish=False): |
| if not finish: |
| # We are trying to remove a possible incomplete multibyte character |
| # from the suffix of the data. |
| # The first byte of a multi-byte sequence is in the range 0xc0 to 0xfd. |
| # All further bytes are in the range 0x80 to 0xbf. |
| # UTF-8 encoded UCS characters may be up to six bytes long. |
| count = 0 |
| while count < 5 and count < len(data) \ |
| and '\x80' <= data[-count-1] <= '\xBF': |
| count -= 1 |
| if count < 5 and count < len(data) \ |
| and '\xC0' <= data[-count-1] <= '\xFD': |
| data = data[:-count-1] |
| return codecs.utf_8_decode(data, errors) |
| |
| 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" \ |
| % (ord(self.character), self.reason, |
| self.name, self.position) |
| |
| class Reader: |
| # 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, data): |
| 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.index = 0 |
| self.line = 0 |
| self.column = 0 |
| if isinstance(data, unicode): |
| self.name = "<unicode string>" |
| self.check_printable(data) |
| self.buffer = data+u'\0' |
| elif isinstance(data, str): |
| self.name = "<string>" |
| self.raw_buffer = data |
| self.determine_encoding() |
| else: |
| self.stream = data |
| self.name = getattr(data, 'name', "<file>") |
| self.eof = False |
| self.raw_buffer = '' |
| self.determine_encoding() |
| |
| def peek(self, index=0): |
| if self.pointer+index+1 >= len(self.buffer): |
| 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) |
| for k in range(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+1] != u'\n'): |
| self.line += 1 |
| self.column = 0 |
| elif ch != u'\uFEFF': |
| self.column += 1 |
| |
| def get_marker(self): |
| if self.stream is None: |
| return Marker(self.name, self.line, self.column, |
| self.buffer, self.pointer) |
| else: |
| return Marker(self.name, 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 = utf_16_le_decode |
| elif self.raw_buffer.startswith(codecs.BOM_UTF16_BE): |
| self.raw_decode = utf_16_be_decode |
| else: |
| self.raw_decode = utf_8_decode |
| self.update(1) |
| |
| 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, 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 |
| |
| #try: |
| # import psyco |
| # psyco.bind(Reader) |
| #except ImportError: |
| # pass |
| |
