html5lib-python/src/html5lib/inputstream.py at python3-old · DKChan/html5lib-python · GitHub

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import codecs

import re

import types

import sys

from .constants import EOF, spaceCharacters, asciiLetters, asciiUppercase

from .constants import encodings, ReparseException

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

spaceCharactersBytes = [str(item) for item in spaceCharacters]

asciiLettersBytes = [str(item) for item in asciiLetters]

asciiUppercaseBytes = [str(item) for item in asciiUppercase]

invalid_unicode_re = re.compile("[\u0001-\u0008\u000B\u000E-\u001F\u007F-\u009F\uD800-\uDFFF\uFDD0-\uFDDF\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]")

ascii_punctuation_re = re.compile(r"[\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

data = rv.append(bufferedData[bufferOffset:

bufferOffset + bytesToRead])

remainingBytes -= bytesToRead

bufferOffset = 0

if remainingBytes:

rv.append(self._readStream(remainingBytes))

return "".join(rv)

class HTMLInputStream:

"""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, 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

"""

# List of where new lines occur

self.newLines = [0]

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

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

# self.charEncoding as appropriate

self.rawStream = self.openStream(source)

# 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)

self.reset()

def reset(self):

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

'replace')

self.chunk = ""

self.chunkSize = 0

self.chunkOffset = 0

self.errors = []

# Remember the current position in the document

self.positionLine = 1

self.positionCol = 0

# Remember the length of the last line, so unget("\n") can restore

# positionCol. (Only one character can be ungot at once, so we only

# need to remember the single last line.)

self.lastLineLength = None

#Flag to indicate we may have a CR LF broken across a data chunk

self._lastChunkEndsWithCR = False

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'):

#This is wrong. We need a generic way to tell the difference

#between file-like objects that produce strings and those that

#produce bytes. We also need a good way to deal with the ones

#that produce strings, in particular getting the replacement

#characters right.

if not hasattr(source, 'encoding'):

stream = source

else:

raise NotImplementedError("Files not opened in binary mode not yet supported")

else:

# Otherwise treat source as a string and convert to a file object

if isinstance(source, str):

source = source.encode('utf-8')

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

import io

stream = io.BytesIO(bytes(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)

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):

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], "certian")

else:

self.rawStream.seek(0)

self.reset()

self.charEncoding = (newEncoding, "certian")

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)

# 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)

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

def updatePosition(self, chars):

# Update the position attributes to correspond to some sequence of

# read characters

# Find the last newline character

idx = chars.rfind("\n")

if idx == -1:

# No newlines in chars

self.positionCol += len(chars)

else:

# Find the last-but-one newline character

idx2 = chars.rfind("\n", 0, idx)

if idx2 == -1:

# Only one newline in chars

self.positionLine += 1

self.lastLineLength = self.positionCol + idx

self.positionCol = len(chars) - (idx + 1)

else:

# At least two newlines in chars

newlines = chars.count("\n")

self.positionLine += newlines

self.lastLineLength = idx - (idx2 + 1)

self.positionCol = len(chars) - (idx + 1)

def position(self):

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

return (self.positionLine, self.positionCol)

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

char = self.chunk[self.chunkOffset]

self.chunkOffset += 1

# Update the position attributes

if char == "\n":

self.lastLineLength = self.positionCol

self.positionCol = 0

self.positionLine += 1

elif char is not EOF:

self.positionCol += 1

return char

def readChunk(self, chunkSize=_defaultChunkSize):

self.chunk = ""

self.chunkSize = 0

self.chunkOffset = 0

data = self.dataStream.read(chunkSize)

if not data:

return False

#Replace null characters

for i in range(data.count("\u0000")):

self.errors.append("null-character")

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

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

data = data.replace("\u0000", "\ufffd")

#Check for CR LF broken across chunks

if (self._lastChunkEndsWithCR and data[0] == "\n"):

data = data[1:]

# Stop if the chunk is now empty

if not data:

return False

self._lastChunkEndsWithCR = data[-1] == "\r"

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

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

self.chunk = data

self.chunkSize = len(data)

return True

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:

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)

self.updatePosition(r)

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

# Update the position attributes

if char == "\n":

assert self.positionLine >= 1

assert self.lastLineLength is not None

self.positionLine -= 1

self.positionCol = self.lastLineLength

self.lastLineLength = None

else:

self.positionCol -= 1

class EncodingBytes(bytes):

"""Bytes-like object with an assosiated position and various extra methods

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

raised"""

def __new__(self, value):

return bytes.__new__(self, value)

def __init__(self, value):

self._position = -1

def __iter__(self):

return self

def __next__(self):

self._position += 1

rv = self[self.position]

return rv

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]

currentByte = property(getCurrentByte)

def skip(self, chars=spaceCharactersBytes):

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

while self.currentByte in chars:

self.position += 1

def matchBytes(self, bytes, lower=False):

"""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"""

data = self[self.position:self.position+len(bytes)]

if lower:

data = data.lower()

rv = data.startswith(bytes)

if rv == True:

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:

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

return True

else:

raise StopIteration

def findNext(self, byteList):

"""Move the pointer so it points to the next byte in a set of possible

bytes"""

while (self.currentByte not in byteList):

self.position += 1

class EncodingParser(object):

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

def __init__(self, data):

"""data - 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, lower=True):

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

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"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()

codec = codecName(tentativeEncoding)

if codec is not None:

self.encoding = codec

return False

def handlePossibleStartTag(self):

return self.handlePossibleTag(False)

def handlePossibleEndTag(self):

self.data.position+=1

return self.handlePossibleTag(True)

def handlePossibleTag(self, endTag):

if self.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:

self.data.position -= 1

self.handleOther()

return True

self.data.findNext(list(spaceCharactersBytes) + [b"<", b">"])

if self.data.currentByte == b"<":

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

#reprocessing the < byte

self.data.position -= 1

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"""

self.data.skip(list(spaceCharactersBytes)+[b"/"])

if self.data.currentByte == b"<":

self.data.position -= 1

return None

elif self.data.currentByte == b">":

return None

attrName = []

attrValue = []

spaceFound = False

#Step 5 attribute name

while True:

if self.data.currentByte == b"=" and attrName:

break

elif self.data.currentByte in spaceCharactersBytes:

spaceFound=True

break

elif self.data.currentByte in (b"/", b"<", b">"):

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

elif self.data.currentByte in asciiUppercaseBytes:

attrName.extend(self.data.currentByte.lower())

else:

attrName.extend(self.data.currentByte)

#Step 6

self.data.position += 1

#Step 7

if spaceFound:

self.data.skip()

#Step 8

if self.data.currentByte != b"=":

self.data.position -= 1

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

#XXX need to advance position in both spaces and value case

#Step 9

self.data.position += 1

#Step 10

self.data.skip()

#Step 11

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

#11.1

quoteChar = self.data.currentByte

while True:

self.data.position+=1

#11.3

if self.data.currentByte == quoteChar:

self.data.position += 1

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

#11.4

elif self.data.currentByte in asciiUppercaseBytes:

attrValue.extend(self.data.currentByte.lower())

#11.5

else:

attrValue.extend(self.data.currentByte)

elif self.data.currentByte in (b">", b"<"):

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

elif self.data.currentByte in asciiUppercaseBytes:

attrValue.extend(self.data.currentByte.lower())

else:

attrValue.extend(self.data.currentByte)

while True:

self.data.position +=1

if self.data.currentByte in (

list(spaceCharactersBytes) + [b">", b"<"]):

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

elif self.data.currentByte in asciiUppercaseBytes:

attrValue.extend(self.data.currentByte.lower())

else:

attrValue.extend(self.data.currentByte)

class ContentAttrParser(object):

def __init__(self, data):

self.data = data

def parse(self):

try:

#Skip to the first ";"

self.data.jumpTo(b";")

self.data.position += 1

self.data.skip()

#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

self.data.jumpTo(quoteMark)

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

else:

#Unquoted value

oldPosition = self.data.position

try:

self.data.findNext(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 type(encoding) == bytes:

encoding = str(encoding, "ascii")

if (encoding is not None) and (type(encoding) == str):

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

return encodings.get(canonicalName, None)

else:

return None

html5lib-python/src/html5lib/inputstream.py at python3-old · DKChan/html5lib-python · GitHub

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