html5lib-python/html5lib/inputstream.py at gcode-157 · html5lib/html5lib-python · GitHub

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from __future__ import absolute_import, division, unicode_literals

from six import text_type

import codecs

import re

import sys

from .constants import EOF, spaceCharacters, asciiLetters, asciiUppercase

from .constants import encodings, ReparseException

from . import utils

from io import StringIO

try:

from io import BytesIO

except ImportError:

BytesIO = StringIO

try:

from io import BufferedIOBase

except ImportError:

class BufferedIOBase(object):

pass

# Non-unicode versions of constants for use in the pre-parser

spaceCharactersBytes = frozenset([item.encode("ascii") for item in spaceCharacters])

asciiLettersBytes = frozenset([item.encode("ascii") for item in asciiLetters])

asciiUppercaseBytes = frozenset([item.encode("ascii") for item in asciiUppercase])

spacesAngleBrackets = spaceCharactersBytes | frozenset([b">", b"<"])

invalid_unicode_re = re.compile("[\u0001-\u0008\u000B\u000E-\u001F\u007F-\u009F\uD800-\uDFFF\uFDD0-\uFDEF\uFFFE\uFFFF\U0001FFFE\U0001FFFF\U0002FFFE\U0002FFFF\U0003FFFE\U0003FFFF\U0004FFFE\U0004FFFF\U0005FFFE\U0005FFFF\U0006FFFE\U0006FFFF\U0007FFFE\U0007FFFF\U0008FFFE\U0008FFFF\U0009FFFE\U0009FFFF\U000AFFFE\U000AFFFF\U000BFFFE\U000BFFFF\U000CFFFE\U000CFFFF\U000DFFFE\U000DFFFF\U000EFFFE\U000EFFFF\U000FFFFE\U000FFFFF\U0010FFFE\U0010FFFF]")

non_bmp_invalid_codepoints = set([0x1FFFE, 0x1FFFF, 0x2FFFE, 0x2FFFF, 0x3FFFE,

0x3FFFF, 0x4FFFE, 0x4FFFF, 0x5FFFE, 0x5FFFF,

0x6FFFE, 0x6FFFF, 0x7FFFE, 0x7FFFF, 0x8FFFE,

0x8FFFF, 0x9FFFE, 0x9FFFF, 0xAFFFE, 0xAFFFF,

0xBFFFE, 0xBFFFF, 0xCFFFE, 0xCFFFF, 0xDFFFE,

0xDFFFF, 0xEFFFE, 0xEFFFF, 0xFFFFE, 0xFFFFF,

0x10FFFE, 0x10FFFF])

ascii_punctuation_re = re.compile("[\u0009-\u000D\u0020-\u002F\u003A-\u0040\u005B-\u0060\u007B-\u007E]")

# Cache for charsUntil()

charsUntilRegEx = {}

class BufferedStream:

"""Buffering for streams that do not have buffering of their own

The buffer is implemented as a list of chunks on the assumption that

joining many strings will be slow since it is O(n**2)

"""

def __init__(self, stream):

self.stream = stream

self.buffer = []

self.position = [-1, 0] # chunk number, offset

def tell(self):

pos = 0

for chunk in self.buffer[:self.position[0]]:

pos += len(chunk)

pos += self.position[1]

return pos

def seek(self, pos):

assert pos < self._bufferedBytes()

offset = pos

i = 0

while len(self.buffer[i]) < offset:

offset -= pos

i += 1

self.position = [i, offset]

def read(self, bytes):

if not self.buffer:

return self._readStream(bytes)

elif (self.position[0] == len(self.buffer) and

self.position[1] == len(self.buffer[-1])):

return self._readStream(bytes)

else:

return self._readFromBuffer(bytes)

def _bufferedBytes(self):

return sum([len(item) for item in self.buffer])

def _readStream(self, bytes):

data = self.stream.read(bytes)

self.buffer.append(data)

self.position[0] += 1

self.position[1] = len(data)

return data

def _readFromBuffer(self, bytes):

remainingBytes = bytes

rv = []

bufferIndex = self.position[0]

bufferOffset = self.position[1]

while bufferIndex < len(self.buffer) and remainingBytes != 0:

assert remainingBytes > 0

bufferedData = self.buffer[bufferIndex]

if remainingBytes <= len(bufferedData) - bufferOffset:

bytesToRead = remainingBytes

self.position = [bufferIndex, bufferOffset + bytesToRead]

else:

bytesToRead = len(bufferedData) - bufferOffset

self.position = [bufferIndex, len(bufferedData)]

bufferIndex += 1

rv.append(bufferedData[bufferOffset:bufferOffset + bytesToRead])

remainingBytes -= bytesToRead

bufferOffset = 0

if remainingBytes:

rv.append(self._readStream(remainingBytes))

return "".join(rv)

def HTMLInputStream(source, encoding=None, parseMeta=True, chardet=True):

if hasattr(source, "read"):

isUnicode = isinstance(source.read(0), text_type)

else:

isUnicode = isinstance(source, text_type)

if isUnicode:

if encoding is not None:

raise TypeError("Cannot explicitly set an encoding with a unicode string")

return HTMLUnicodeInputStream(source)

else:

return HTMLBinaryInputStream(source, encoding, parseMeta, chardet)

class HTMLUnicodeInputStream:

"""Provides a unicode stream of characters to the HTMLTokenizer.

This class takes care of character encoding and removing or replacing

incorrect byte-sequences and also provides column and line tracking.

"""

_defaultChunkSize = 10240

def __init__(self, source):

"""Initialises the HTMLInputStream.

HTMLInputStream(source, [encoding]) -> Normalized stream from source

for use by html5lib.

source can be either a file-object, local filename or a string.

The optional encoding parameter must be a string that indicates

the encoding. If specified, that encoding will be used,

regardless of any BOM or later declaration (such as in a meta

element)

parseMeta - Look for a <meta> element containing encoding information

"""

# Craziness

if len("\U0010FFFF") == 1:

self.reportCharacterErrors = self.characterErrorsUCS4

self.replaceCharactersRegexp = re.compile("[\uD800-\uDFFF]")

else:

self.reportCharacterErrors = self.characterErrorsUCS2

self.replaceCharactersRegexp = re.compile("([\uD800-\uDBFF](?![\uDC00-\uDFFF])|(?<![\uD800-\uDBFF])[\uDC00-\uDFFF])")

# List of where new lines occur

self.newLines = [0]

self.charEncoding = ("utf-8", "certain")

self.dataStream = self.openStream(source)

self.reset()

def reset(self):

self.chunk = ""

self.chunkSize = 0

self.chunkOffset = 0

self.errors = []

# number of (complete) lines in previous chunks

self.prevNumLines = 0

# number of columns in the last line of the previous chunk

self.prevNumCols = 0

# Deal with CR LF and surrogates split over chunk boundaries

self._bufferedCharacter = None

def openStream(self, source):

"""Produces a file object from source.

source can be either a file object, local filename or a string.

"""

# Already a file object

if hasattr(source, 'read'):

stream = source

else:

stream = StringIO(source)

if ( # not isinstance(stream, BufferedIOBase) and

not(hasattr(stream, "tell") and

hasattr(stream, "seek")) or

stream is sys.stdin):

stream = BufferedStream(stream)

return stream

def _position(self, offset):

chunk = self.chunk

nLines = chunk.count('\n', 0, offset)

positionLine = self.prevNumLines + nLines

lastLinePos = chunk.rfind('\n', 0, offset)

if lastLinePos == -1:

positionColumn = self.prevNumCols + offset

else:

positionColumn = offset - (lastLinePos + 1)

return (positionLine, positionColumn)

def position(self):

"""Returns (line, col) of the current position in the stream."""

line, col = self._position(self.chunkOffset)

return (line + 1, col)

def char(self):

""" Read one character from the stream or queue if available. Return

EOF when EOF is reached.

"""

# Read a new chunk from the input stream if necessary

if self.chunkOffset >= self.chunkSize:

if not self.readChunk():

return EOF

chunkOffset = self.chunkOffset

char = self.chunk[chunkOffset]

self.chunkOffset = chunkOffset + 1

return char

def readChunk(self, chunkSize=None):

if chunkSize is None:

chunkSize = self._defaultChunkSize

self.prevNumLines, self.prevNumCols = self._position(self.chunkSize)

self.chunk = ""

self.chunkSize = 0

self.chunkOffset = 0

data = self.dataStream.read(chunkSize)

# Deal with CR LF and surrogates broken across chunks

if self._bufferedCharacter:

data = self._bufferedCharacter + data

self._bufferedCharacter = None

elif not data:

# We have no more data, bye-bye stream

return False

if len(data) > 1:

lastv = ord(data[-1])

if lastv == 0x0D or 0xD800 <= lastv <= 0xDBFF:

self._bufferedCharacter = data[-1]

data = data[:-1]

self.reportCharacterErrors(data)

# Replace invalid characters

# Note U+0000 is dealt with in the tokenizer

data = self.replaceCharactersRegexp.sub("\ufffd", data)

data = data.replace("\r\n", "\n")

data = data.replace("\r", "\n")

self.chunk = data

self.chunkSize = len(data)

return True

def characterErrorsUCS4(self, data):

for i in range(len(invalid_unicode_re.findall(data))):

self.errors.append("invalid-codepoint")

def characterErrorsUCS2(self, data):

# Someone picked the wrong compile option

# You lose

skip = False

for match in invalid_unicode_re.finditer(data):

if skip:

continue

codepoint = ord(match.group())

pos = match.start()

# Pretty sure there should be endianness issues here

if utils.isSurrogatePair(data[pos:pos + 2]):

# We have a surrogate pair!

char_val = utils.surrogatePairToCodepoint(data[pos:pos + 2])

if char_val in non_bmp_invalid_codepoints:

self.errors.append("invalid-codepoint")

skip = True

elif (codepoint >= 0xD800 and codepoint <= 0xDFFF and

pos == len(data) - 1):

self.errors.append("invalid-codepoint")

else:

skip = False

self.errors.append("invalid-codepoint")

def charsUntil(self, characters, opposite=False):

""" Returns a string of characters from the stream up to but not

including any character in 'characters' or EOF. 'characters' must be

a container that supports the 'in' method and iteration over its

characters.

"""

# Use a cache of regexps to find the required characters

try:

chars = charsUntilRegEx[(characters, opposite)]

except KeyError:

if __debug__:

for c in characters:

assert(ord(c) < 128)

regex = "".join(["\\x%02x" % ord(c) for c in characters])

if not opposite:

regex = "^%s" % regex

chars = charsUntilRegEx[(characters, opposite)] = re.compile("[%s]+" % regex)

rv = []

while True:

# Find the longest matching prefix

m = chars.match(self.chunk, self.chunkOffset)

if m is None:

# If nothing matched, and it wasn't because we ran out of chunk,

# then stop

if self.chunkOffset != self.chunkSize:

break

else:

end = m.end()

# If not the whole chunk matched, return everything

# up to the part that didn't match

if end != self.chunkSize:

rv.append(self.chunk[self.chunkOffset:end])

self.chunkOffset = end

break

# If the whole remainder of the chunk matched,

# use it all and read the next chunk

rv.append(self.chunk[self.chunkOffset:])

if not self.readChunk():

# Reached EOF

break

r = "".join(rv)

return r

def unget(self, char):

# Only one character is allowed to be ungotten at once - it must

# be consumed again before any further call to unget

if char is not None:

if self.chunkOffset == 0:

# unget is called quite rarely, so it's a good idea to do

# more work here if it saves a bit of work in the frequently

# called char and charsUntil.

# So, just prepend the ungotten character onto the current

# chunk:

self.chunk = char + self.chunk

self.chunkSize += 1

else:

self.chunkOffset -= 1

assert self.chunk[self.chunkOffset] == char

class HTMLBinaryInputStream(HTMLUnicodeInputStream):

"""Provides a unicode stream of characters to the HTMLTokenizer.

This class takes care of character encoding and removing or replacing

incorrect byte-sequences and also provides column and line tracking.

"""

def __init__(self, source, encoding=None, parseMeta=True, chardet=True):

"""Initialises the HTMLInputStream.

HTMLInputStream(source, [encoding]) -> Normalized stream from source

for use by html5lib.

source can be either a file-object, local filename or a string.

The optional encoding parameter must be a string that indicates

the encoding. If specified, that encoding will be used,

regardless of any BOM or later declaration (such as in a meta

element)

parseMeta - Look for a <meta> element containing encoding information

"""

# Raw Stream - for unicode objects this will encode to utf-8 and set

# self.charEncoding as appropriate

self.rawStream = self.openStream(source)

HTMLUnicodeInputStream.__init__(self, self.rawStream)

self.charEncoding = (codecName(encoding), "certain")

# Encoding Information

# Number of bytes to use when looking for a meta element with

# encoding information

self.numBytesMeta = 512

# Number of bytes to use when using detecting encoding using chardet

self.numBytesChardet = 100

# Encoding to use if no other information can be found

self.defaultEncoding = "windows-1252"

# Detect encoding iff no explicit "transport level" encoding is supplied

if (self.charEncoding[0] is None):

self.charEncoding = self.detectEncoding(parseMeta, chardet)

# Call superclass

self.reset()

def reset(self):

self.dataStream = codecs.getreader(self.charEncoding[0])(self.rawStream,

'replace')

HTMLUnicodeInputStream.reset(self)

def openStream(self, source):

"""Produces a file object from source.

source can be either a file object, local filename or a string.

"""

# Already a file object

if hasattr(source, 'read'):

stream = source

else:

stream = BytesIO(source)

if (not(hasattr(stream, "tell") and hasattr(stream, "seek")) or

stream is sys.stdin):

stream = BufferedStream(stream)

return stream

def detectEncoding(self, parseMeta=True, chardet=True):

# First look for a BOM

# This will also read past the BOM if present

encoding = self.detectBOM()

confidence = "certain"

# If there is no BOM need to look for meta elements with encoding

# information

if encoding is None and parseMeta:

encoding = self.detectEncodingMeta()

confidence = "tentative"

# Guess with chardet, if avaliable

if encoding is None and chardet:

confidence = "tentative"

try:

from chardet.universaldetector import UniversalDetector

buffers = []

detector = UniversalDetector()

while not detector.done:

buffer = self.rawStream.read(self.numBytesChardet)

assert isinstance(buffer, bytes)

if not buffer:

break

buffers.append(buffer)

detector.feed(buffer)

detector.close()

encoding = detector.result['encoding']

self.rawStream.seek(0)

except ImportError:

pass

# If all else fails use the default encoding

if encoding is None:

confidence = "tentative"

encoding = self.defaultEncoding

# Substitute for equivalent encodings:

encodingSub = {"iso-8859-1": "windows-1252"}

if encoding.lower() in encodingSub:

encoding = encodingSub[encoding.lower()]

return encoding, confidence

def changeEncoding(self, newEncoding):

assert self.charEncoding[1] != "certain"

newEncoding = codecName(newEncoding)

if newEncoding in ("utf-16", "utf-16-be", "utf-16-le"):

newEncoding = "utf-8"

if newEncoding is None:

return

elif newEncoding == self.charEncoding[0]:

self.charEncoding = (self.charEncoding[0], "certain")

else:

self.rawStream.seek(0)

self.reset()

self.charEncoding = (newEncoding, "certain")

raise ReparseException("Encoding changed from %s to %s" % (self.charEncoding[0], newEncoding))

def detectBOM(self):

"""Attempts to detect at BOM at the start of the stream. If

an encoding can be determined from the BOM return the name of the

encoding otherwise return None"""

bomDict = {

codecs.BOM_UTF8: 'utf-8',

codecs.BOM_UTF16_LE: 'utf-16-le', codecs.BOM_UTF16_BE: 'utf-16-be',

codecs.BOM_UTF32_LE: 'utf-32-le', codecs.BOM_UTF32_BE: 'utf-32-be'

}

# Go to beginning of file and read in 4 bytes

string = self.rawStream.read(4)

assert isinstance(string, bytes)

# Try detecting the BOM using bytes from the string

encoding = bomDict.get(string[:3]) # UTF-8

seek = 3

if not encoding:

# Need to detect UTF-32 before UTF-16

encoding = bomDict.get(string) # UTF-32

seek = 4

if not encoding:

encoding = bomDict.get(string[:2]) # UTF-16

seek = 2

# Set the read position past the BOM if one was found, otherwise

# set it to the start of the stream

self.rawStream.seek(encoding and seek or 0)

return encoding

def detectEncodingMeta(self):

"""Report the encoding declared by the meta element

"""

buffer = self.rawStream.read(self.numBytesMeta)

assert isinstance(buffer, bytes)

parser = EncodingParser(buffer)

self.rawStream.seek(0)

encoding = parser.getEncoding()

if encoding in ("utf-16", "utf-16-be", "utf-16-le"):

encoding = "utf-8"

return encoding

class EncodingBytes(bytes):

"""String-like object with an associated position and various extra methods

If the position is ever greater than the string length then an exception is

raised"""

def __new__(self, value):

assert isinstance(value, bytes)

return bytes.__new__(self, value.lower())

def __init__(self, value):

self._position = -1

def __iter__(self):

return self

def __next__(self):

p = self._position = self._position + 1

if p >= len(self):

raise StopIteration

elif p < 0:

raise TypeError

return self[p:p + 1]

def next(self):

# Py2 compat

return self.__next__()

def previous(self):

p = self._position

if p >= len(self):

raise StopIteration

elif p < 0:

raise TypeError

self._position = p = p - 1

return self[p:p + 1]

def setPosition(self, position):

if self._position >= len(self):

raise StopIteration

self._position = position

def getPosition(self):

if self._position >= len(self):

raise StopIteration

if self._position >= 0:

return self._position

else:

return None

position = property(getPosition, setPosition)

def getCurrentByte(self):

return self[self.position:self.position + 1]

currentByte = property(getCurrentByte)

def skip(self, chars=spaceCharactersBytes):

"""Skip past a list of characters"""

p = self.position # use property for the error-checking

while p < len(self):

c = self[p:p + 1]

if c not in chars:

self._position = p

return c

p += 1

self._position = p

return None

def skipUntil(self, chars):

p = self.position

while p < len(self):

c = self[p:p + 1]

if c in chars:

self._position = p

return c

p += 1

self._position = p

return None

def matchBytes(self, bytes):

"""Look for a sequence of bytes at the start of a string. If the bytes

are found return True and advance the position to the byte after the

match. Otherwise return False and leave the position alone"""

p = self.position

data = self[p:p + len(bytes)]

rv = data.startswith(bytes)

if rv:

self.position += len(bytes)

return rv

def jumpTo(self, bytes):

"""Look for the next sequence of bytes matching a given sequence. If

a match is found advance the position to the last byte of the match"""

newPosition = self[self.position:].find(bytes)

if newPosition > -1:

# XXX: This is ugly, but I can't see a nicer way to fix this.

if self._position == -1:

self._position = 0

self._position += (newPosition + len(bytes) - 1)

return True

else:

raise StopIteration

class EncodingParser(object):

"""Mini parser for detecting character encoding from meta elements"""

def __init__(self, data):

"""string - the data to work on for encoding detection"""

self.data = EncodingBytes(data)

self.encoding = None

def getEncoding(self):

methodDispatch = (

(b"<!--", self.handleComment),

(b"<meta", self.handleMeta),

(b"</", self.handlePossibleEndTag),

(b"<!", self.handleOther),

(b"<?", self.handleOther),

(b"<", self.handlePossibleStartTag))

for byte in self.data:

keepParsing = True

for key, method in methodDispatch:

if self.data.matchBytes(key):

try:

keepParsing = method()

break

except StopIteration:

keepParsing = False

break

if not keepParsing:

break

return self.encoding

def handleComment(self):

"""Skip over comments"""

return self.data.jumpTo(b"-->")

def handleMeta(self):

if self.data.currentByte not in spaceCharactersBytes:

# if we have <meta not followed by a space so just keep going

return True

# We have a valid meta element we want to search for attributes

hasPragma = False

pendingEncoding = None

while True:

# Try to find the next attribute after the current position

attr = self.getAttribute()

if attr is None:

return True

else:

if attr[0] == b"http-equiv":

hasPragma = attr[1] == b"content-type"

if hasPragma and pendingEncoding is not None:

self.encoding = pendingEncoding

return False

elif attr[0] == b"charset":

tentativeEncoding = attr[1]

codec = codecName(tentativeEncoding)

if codec is not None:

self.encoding = codec

return False

elif attr[0] == b"content":

contentParser = ContentAttrParser(EncodingBytes(attr[1]))

tentativeEncoding = contentParser.parse()

if tentativeEncoding is not None:

codec = codecName(tentativeEncoding)

if codec is not None:

if hasPragma:

self.encoding = codec

return False

else:

pendingEncoding = codec

def handlePossibleStartTag(self):

return self.handlePossibleTag(False)

def handlePossibleEndTag(self):

next(self.data)

return self.handlePossibleTag(True)

def handlePossibleTag(self, endTag):

data = self.data

if data.currentByte not in asciiLettersBytes:

# If the next byte is not an ascii letter either ignore this

# fragment (possible start tag case) or treat it according to

# handleOther

if endTag:

data.previous()

self.handleOther()

return True

c = data.skipUntil(spacesAngleBrackets)

if c == b"<":

# return to the first step in the overall "two step" algorithm

# reprocessing the < byte

data.previous()

else:

# Read all attributes

attr = self.getAttribute()

while attr is not None:

attr = self.getAttribute()

return True

def handleOther(self):

return self.data.jumpTo(b">")

def getAttribute(self):

"""Return a name,value pair for the next attribute in the stream,

if one is found, or None"""

data = self.data

# Step 1 (skip chars)

c = data.skip(spaceCharactersBytes | frozenset([b"/"]))

assert c is None or len(c) == 1

# Step 2

if c in (b">", None):

return None

# Step 3

attrName = []

attrValue = []

# Step 4 attribute name

while True:

if c == b"=" and attrName:

break

elif c in spaceCharactersBytes:

# Step 6!

c = data.skip()

break

elif c in (b"/", b">"):

return b"".join(attrName), b""

elif c in asciiUppercaseBytes:

attrName.append(c.lower())

elif c is None:

return None

else:

attrName.append(c)

# Step 5

c = next(data)

# Step 7

if c != b"=":

data.previous()

return b"".join(attrName), b""

# Step 8

next(data)

# Step 9

c = data.skip()

# Step 10

if c in (b"'", b'"'):

# 10.1

quoteChar = c

while True:

# 10.2

c = next(data)

# 10.3

if c == quoteChar:

next(data)

return b"".join(attrName), b"".join(attrValue)

# 10.4

elif c in asciiUppercaseBytes:

attrValue.append(c.lower())

# 10.5

else:

attrValue.append(c)

elif c == b">":

return b"".join(attrName), b""

elif c in asciiUppercaseBytes:

attrValue.append(c.lower())

elif c is None:

return None

else:

attrValue.append(c)

# Step 11

while True:

c = next(data)

if c in spacesAngleBrackets:

return b"".join(attrName), b"".join(attrValue)

elif c in asciiUppercaseBytes:

attrValue.append(c.lower())

elif c is None:

return None

else:

attrValue.append(c)

class ContentAttrParser(object):

def __init__(self, data):

assert isinstance(data, bytes)

self.data = data

def parse(self):

try:

# Check if the attr name is charset

# otherwise return

self.data.jumpTo(b"charset")

self.data.position += 1

self.data.skip()

if not self.data.currentByte == b"=":

# If there is no = sign keep looking for attrs

return None

self.data.position += 1

self.data.skip()

# Look for an encoding between matching quote marks

if self.data.currentByte in (b'"', b"'"):

quoteMark = self.data.currentByte

self.data.position += 1

oldPosition = self.data.position

if self.data.jumpTo(quoteMark):

return self.data[oldPosition:self.data.position]

else:

return None

else:

# Unquoted value

oldPosition = self.data.position

try:

self.data.skipUntil(spaceCharactersBytes)

return self.data[oldPosition:self.data.position]

except StopIteration:

# Return the whole remaining value

return self.data[oldPosition:]

except StopIteration:

return None

def codecName(encoding):

"""Return the python codec name corresponding to an encoding or None if the

string doesn't correspond to a valid encoding."""

if isinstance(encoding, bytes):

try:

encoding = encoding.decode("ascii")

except UnicodeDecodeError:

return None

if encoding:

canonicalName = ascii_punctuation_re.sub("", encoding).lower()

return encodings.get(canonicalName, None)

else:

return None

html5lib-python/html5lib/inputstream.py at gcode-157 · html5lib/html5lib-python · GitHub

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