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usr
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lib
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python3.8
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xml
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sax
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Filename :
saxutils.py
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"""\ A library of useful helper classes to the SAX classes, for the convenience of application and driver writers. """ import os, urllib.parse, urllib.request import io import codecs from . import handler from . import xmlreader def __dict_replace(s, d): """Replace substrings of a string using a dictionary.""" for key, value in d.items(): s = s.replace(key, value) return s def escape(data, entities={}): """Escape &, <, and > in a string of data. You can escape other strings of data by passing a dictionary as the optional entities parameter. The keys and values must all be strings; each key will be replaced with its corresponding value. """ # must do ampersand first data = data.replace("&", "&") data = data.replace(">", ">") data = data.replace("<", "<") if entities: data = __dict_replace(data, entities) return data def unescape(data, entities={}): """Unescape &, <, and > in a string of data. You can unescape other strings of data by passing a dictionary as the optional entities parameter. The keys and values must all be strings; each key will be replaced with its corresponding value. """ data = data.replace("<", "<") data = data.replace(">", ">") if entities: data = __dict_replace(data, entities) # must do ampersand last return data.replace("&", "&") def quoteattr(data, entities={}): """Escape and quote an attribute value. Escape &, <, and > in a string of data, then quote it for use as an attribute value. The \" character will be escaped as well, if necessary. You can escape other strings of data by passing a dictionary as the optional entities parameter. The keys and values must all be strings; each key will be replaced with its corresponding value. """ entities = {**entities, '\n': ' ', '\r': ' ', '\t':'	'} data = escape(data, entities) if '"' in data: if "'" in data: data = '"%s"' % data.replace('"', """) else: data = "'%s'" % data else: data = '"%s"' % data return data def _gettextwriter(out, encoding): if out is None: import sys return sys.stdout if isinstance(out, io.TextIOBase): # use a text writer as is return out if isinstance(out, (codecs.StreamWriter, codecs.StreamReaderWriter)): # use a codecs stream writer as is return out # wrap a binary writer with TextIOWrapper if isinstance(out, io.RawIOBase): # Keep the original file open when the TextIOWrapper is # destroyed class _wrapper: __class__ = out.__class__ def __getattr__(self, name): return getattr(out, name) buffer = _wrapper() buffer.close = lambda: None else: # This is to handle passed objects that aren't in the # IOBase hierarchy, but just have a write method buffer = io.BufferedIOBase() buffer.writable = lambda: True buffer.write = out.write try: # TextIOWrapper uses this methods to determine # if BOM (for UTF-16, etc) should be added buffer.seekable = out.seekable buffer.tell = out.tell except AttributeError: pass return io.TextIOWrapper(buffer, encoding=encoding, errors='xmlcharrefreplace', newline='\n', write_through=True) class XMLGenerator(handler.ContentHandler): def __init__(self, out=None, encoding="iso-8859-1", short_empty_elements=False): handler.ContentHandler.__init__(self) out = _gettextwriter(out, encoding) self._write = out.write self._flush = out.flush self._ns_contexts = [{}] # contains uri -> prefix dicts self._current_context = self._ns_contexts[-1] self._undeclared_ns_maps = [] self._encoding = encoding self._short_empty_elements = short_empty_elements self._pending_start_element = False def _qname(self, name): """Builds a qualified name from a (ns_url, localname) pair""" if name[0]: # Per http://www.w3.org/XML/1998/namespace, The 'xml' prefix is # bound by definition to http://www.w3.org/XML/1998/namespace. It # does not need to be declared and will not usually be found in # self._current_context. if 'http://www.w3.org/XML/1998/namespace' == name[0]: return 'xml:' + name[1] # The name is in a non-empty namespace prefix = self._current_context[name[0]] if prefix: # If it is not the default namespace, prepend the prefix return prefix + ":" + name[1] # Return the unqualified name return name[1] def _finish_pending_start_element(self,endElement=False): if self._pending_start_element: self._write('>') self._pending_start_element = False # ContentHandler methods def startDocument(self): self._write('<?xml version="1.0" encoding="%s"?>\n' % self._encoding) def endDocument(self): self._flush() def startPrefixMapping(self, prefix, uri): self._ns_contexts.append(self._current_context.copy()) self._current_context[uri] = prefix self._undeclared_ns_maps.append((prefix, uri)) def endPrefixMapping(self, prefix): self._current_context = self._ns_contexts[-1] del self._ns_contexts[-1] def startElement(self, name, attrs): self._finish_pending_start_element() self._write('<' + name) for (name, value) in attrs.items(): self._write(' %s=%s' % (name, quoteattr(value))) if self._short_empty_elements: self._pending_start_element = True else: self._write(">") def endElement(self, name): if self._pending_start_element: self._write('/>') self._pending_start_element = False else: self._write('</%s>' % name) def startElementNS(self, name, qname, attrs): self._finish_pending_start_element() self._write('<' + self._qname(name)) for prefix, uri in self._undeclared_ns_maps: if prefix: self._write(' xmlns:%s="%s"' % (prefix, uri)) else: self._write(' xmlns="%s"' % uri) self._undeclared_ns_maps = [] for (name, value) in attrs.items(): self._write(' %s=%s' % (self._qname(name), quoteattr(value))) if self._short_empty_elements: self._pending_start_element = True else: self._write(">") def endElementNS(self, name, qname): if self._pending_start_element: self._write('/>') self._pending_start_element = False else: self._write('</%s>' % self._qname(name)) def characters(self, content): if content: self._finish_pending_start_element() if not isinstance(content, str): content = str(content, self._encoding) self._write(escape(content)) def ignorableWhitespace(self, content): if content: self._finish_pending_start_element() if not isinstance(content, str): content = str(content, self._encoding) self._write(content) def processingInstruction(self, target, data): self._finish_pending_start_element() self._write('<?%s %s?>' % (target, data)) class XMLFilterBase(xmlreader.XMLReader): """This class is designed to sit between an XMLReader and the client application's event handlers. By default, it does nothing but pass requests up to the reader and events on to the handlers unmodified, but subclasses can override specific methods to modify the event stream or the configuration requests as they pass through.""" def __init__(self, parent = None): xmlreader.XMLReader.__init__(self) self._parent = parent # ErrorHandler methods def error(self, exception): self._err_handler.error(exception) def fatalError(self, exception): self._err_handler.fatalError(exception) def warning(self, exception): self._err_handler.warning(exception) # ContentHandler methods def setDocumentLocator(self, locator): self._cont_handler.setDocumentLocator(locator) def startDocument(self): self._cont_handler.startDocument() def endDocument(self): self._cont_handler.endDocument() def startPrefixMapping(self, prefix, uri): self._cont_handler.startPrefixMapping(prefix, uri) def endPrefixMapping(self, prefix): self._cont_handler.endPrefixMapping(prefix) def startElement(self, name, attrs): self._cont_handler.startElement(name, attrs) def endElement(self, name): self._cont_handler.endElement(name) def startElementNS(self, name, qname, attrs): self._cont_handler.startElementNS(name, qname, attrs) def endElementNS(self, name, qname): self._cont_handler.endElementNS(name, qname) def characters(self, content): self._cont_handler.characters(content) def ignorableWhitespace(self, chars): self._cont_handler.ignorableWhitespace(chars) def processingInstruction(self, target, data): self._cont_handler.processingInstruction(target, data) def skippedEntity(self, name): self._cont_handler.skippedEntity(name) # DTDHandler methods def notationDecl(self, name, publicId, systemId): self._dtd_handler.notationDecl(name, publicId, systemId) def unparsedEntityDecl(self, name, publicId, systemId, ndata): self._dtd_handler.unparsedEntityDecl(name, publicId, systemId, ndata) # EntityResolver methods def resolveEntity(self, publicId, systemId): return self._ent_handler.resolveEntity(publicId, systemId) # XMLReader methods def parse(self, source): self._parent.setContentHandler(self) self._parent.setErrorHandler(self) self._parent.setEntityResolver(self) self._parent.setDTDHandler(self) self._parent.parse(source) def setLocale(self, locale): self._parent.setLocale(locale) def getFeature(self, name): return self._parent.getFeature(name) def setFeature(self, name, state): self._parent.setFeature(name, state) def getProperty(self, name): return self._parent.getProperty(name) def setProperty(self, name, value): self._parent.setProperty(name, value) # XMLFilter methods def getParent(self): return self._parent def setParent(self, parent): self._parent = parent # --- Utility functions def prepare_input_source(source, base=""): """This function takes an InputSource and an optional base URL and returns a fully resolved InputSource object ready for reading.""" if isinstance(source, os.PathLike): source = os.fspath(source) if isinstance(source, str): source = xmlreader.InputSource(source) elif hasattr(source, "read"): f = source source = xmlreader.InputSource() if isinstance(f.read(0), str): source.setCharacterStream(f) else: source.setByteStream(f) if hasattr(f, "name") and isinstance(f.name, str): source.setSystemId(f.name) if source.getCharacterStream() is None and source.getByteStream() is None: sysid = source.getSystemId() basehead = os.path.dirname(os.path.normpath(base)) sysidfilename = os.path.join(basehead, sysid) if os.path.isfile(sysidfilename): source.setSystemId(sysidfilename) f = open(sysidfilename, "rb") else: source.setSystemId(urllib.parse.urljoin(base, sysid)) f = urllib.request.urlopen(source.getSystemId()) source.setByteStream(f) return source