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Edit File: _inputstream.py
from __future__ import absolute_import, division, unicode_literals from six import text_type from six.moves import http_client, urllib import codecs import re from io import BytesIO, StringIO import webencodings from .constants import EOF, spaceCharacters, asciiLetters, asciiUppercase from .constants import _ReparseException from . import _utils # 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_no_surrogate = "[\u0001-\u0008\u000B\u000E-\u001F\u007F-\u009F\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]" # noqa if _utils.supports_lone_surrogates: # Use one extra step of indirection and create surrogates with # eval. Not using this indirection would introduce an illegal # unicode literal on platforms not supporting such lone # surrogates. assert invalid_unicode_no_surrogate[-1] == "]" and invalid_unicode_no_surrogate.count("]") == 1 invalid_unicode_re = re.compile(invalid_unicode_no_surrogate[:-1] + eval('"\\uD800-\\uDFFF"') + # pylint:disable=eval-used "]") else: invalid_unicode_re = re.compile(invalid_unicode_no_surrogate) non_bmp_invalid_codepoints = {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\u005C\u005B-\u0060\u007B-\u007E]") # Cache for charsUntil() charsUntilRegEx = {} class BufferedStream(object): """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 -= len(self.buffer[i]) 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 b"".join(rv) def HTMLInputStream(source, **kwargs): # Work around Python bug #20007: read(0) closes the connection. # http://bugs.python.org/issue20007 if (isinstance(source, http_client.HTTPResponse) or # Also check for addinfourl wrapping HTTPResponse (isinstance(source, urllib.response.addbase) and isinstance(source.fp, http_client.HTTPResponse))): isUnicode = False elif hasattr(source, "read"): isUnicode = isinstance(source.read(0), text_type) else: isUnicode = isinstance(source, text_type) if isUnicode: encodings = [x for x in kwargs if x.endswith("_encoding")] if encodings: raise TypeError("Cannot set an encoding with a unicode input, set %r" % encodings) return HTMLUnicodeInputStream(source, **kwargs) else: return HTMLBinaryInputStream(source, **kwargs) class HTMLUnicodeInputStream(object): """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) """ if not _utils.supports_lone_surrogates: # Such platforms will have already checked for such # surrogate errors, so no need to do this checking. self.reportCharacterErrors = None elif len("\U0010FFFF") == 1: self.reportCharacterErrors = self.characterErrorsUCS4 else: self.reportCharacterErrors = self.characterErrorsUCS2 # List of where new lines occur self.newLines = [0] self.charEncoding = (lookupEncoding("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) 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] if self.reportCharacterErrors: self.reportCharacterErrors(data) # Replace invalid characters 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 _ 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 EOF: 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, override_encoding=None, transport_encoding=None, same_origin_parent_encoding=None, likely_encoding=None, default_encoding="windows-1252", useChardet=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) """ # 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) # Encoding Information # Number of bytes to use when looking for a meta element with # encoding information self.numBytesMeta = 1024 # Number of bytes to use when using detecting encoding using chardet self.numBytesChardet = 100 # Things from args self.override_encoding = override_encoding self.transport_encoding = transport_encoding self.same_origin_parent_encoding = same_origin_parent_encoding self.likely_encoding = likely_encoding self.default_encoding = default_encoding # Determine encoding self.charEncoding = self.determineEncoding(useChardet) assert self.charEncoding[0] is not None # Call superclass self.reset() def reset(self): self.dataStream = self.charEncoding[0].codec_info.streamreader(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) try: stream.seek(stream.tell()) except Exception: stream = BufferedStream(stream) return stream def determineEncoding(self, chardet=True): # BOMs take precedence over everything # This will also read past the BOM if present charEncoding = self.detectBOM(), "certain" if charEncoding[0] is not None: return charEncoding # If we've been overridden, we've been overridden charEncoding = lookupEncoding(self.override_encoding), "certain" if charEncoding[0] is not None: return charEncoding # Now check the transport layer charEncoding = lookupEncoding(self.transport_encoding), "certain" if charEncoding[0] is not None: return charEncoding # Look for meta elements with encoding information charEncoding = self.detectEncodingMeta(), "tentative" if charEncoding[0] is not None: return charEncoding # Parent document encoding charEncoding = lookupEncoding(self.same_origin_parent_encoding), "tentative" if charEncoding[0] is not None and not charEncoding[0].name.startswith("utf-16"): return charEncoding # "likely" encoding charEncoding = lookupEncoding(self.likely_encoding), "tentative" if charEncoding[0] is not None: return charEncoding # Guess with chardet, if available if chardet: try: from chardet.universaldetector import UniversalDetector except ImportError: pass else: 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 = lookupEncoding(detector.result['encoding']) self.rawStream.seek(0) if encoding is not None: return encoding, "tentative" # Try the default encoding charEncoding = lookupEncoding(self.default_encoding), "tentative" if charEncoding[0] is not None: return charEncoding # Fallback to html5lib's default if even that hasn't worked return lookupEncoding("windows-1252"), "tentative" def changeEncoding(self, newEncoding): assert self.charEncoding[1] != "certain" newEncoding = lookupEncoding(newEncoding) if newEncoding is None: return if newEncoding.name in ("utf-16be", "utf-16le"): newEncoding = lookupEncoding("utf-8") assert newEncoding is not None elif newEncoding == self.charEncoding[0]: self.charEncoding = (self.charEncoding[0], "certain") else: self.rawStream.seek(0) self.charEncoding = (newEncoding, "certain") self.reset() 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-16le', codecs.BOM_UTF16_BE: 'utf-16be', codecs.BOM_UTF32_LE: 'utf-32le', codecs.BOM_UTF32_BE: 'utf-32be' } # 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 if encoding: self.rawStream.seek(seek) return lookupEncoding(encoding) else: self.rawStream.seek(0) return None 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 is not None and encoding.name in ("utf-16be", "utf-16le"): encoding = lookupEncoding("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): # pylint:disable=unused-argument 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""" rv = self.startswith(bytes, self.position) 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""" try: self._position = self.index(bytes, self.position) + len(bytes) - 1 except ValueError: raise StopIteration return True 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): if b"<meta" not in self.data: return None methodDispatch = ( (b"<!--", self.handleComment), (b"<meta", self.handleMeta), (b"</", self.handlePossibleEndTag), (b"<!", self.handleOther), (b"<?", self.handleOther), (b"<", self.handlePossibleStartTag)) for _ in self.data: keepParsing = True try: self.data.jumpTo(b"<") except StopIteration: break 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 = lookupEncoding(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 = lookupEncoding(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 lookupEncoding(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 is not None: try: return webencodings.lookup(encoding) except AttributeError: return None else: return None