Chip 2011 November

home *** CD-ROM | disk | FTP | other *** search

/ Chip 2011 November / CHIP_2011_11.iso / Programy / Narzedzia / Inkscape / Inkscape-0.48.2-1-win32.exe / python / Lib / xml / etree / ElementTree.py < prev

Wrap

Text File | 2010-03-06 | 41.3 KB | 1,261 lines

# # ElementTree # $Id: ElementTree.py 2326 2005-03-17 07:45:21Z fredrik $ # # light-weight XML support for Python 1.5.2 and later. # # history: # 2001-10-20 fl created (from various sources) # 2001-11-01 fl return root from parse method # 2002-02-16 fl sort attributes in lexical order # 2002-04-06 fl TreeBuilder refactoring, added PythonDoc markup # 2002-05-01 fl finished TreeBuilder refactoring # 2002-07-14 fl added basic namespace support to ElementTree.write # 2002-07-25 fl added QName attribute support # 2002-10-20 fl fixed encoding in write # 2002-11-24 fl changed default encoding to ascii; fixed attribute encoding # 2002-11-27 fl accept file objects or file names for parse/write # 2002-12-04 fl moved XMLTreeBuilder back to this module # 2003-01-11 fl fixed entity encoding glitch for us-ascii # 2003-02-13 fl added XML literal factory # 2003-02-21 fl added ProcessingInstruction/PI factory # 2003-05-11 fl added tostring/fromstring helpers # 2003-05-26 fl added ElementPath support # 2003-07-05 fl added makeelement factory method # 2003-07-28 fl added more well-known namespace prefixes # 2003-08-15 fl fixed typo in ElementTree.findtext (Thomas Dartsch) # 2003-09-04 fl fall back on emulator if ElementPath is not installed # 2003-10-31 fl markup updates # 2003-11-15 fl fixed nested namespace bug # 2004-03-28 fl added XMLID helper # 2004-06-02 fl added default support to findtext # 2004-06-08 fl fixed encoding of non-ascii element/attribute names # 2004-08-23 fl take advantage of post-2.1 expat features # 2005-02-01 fl added iterparse implementation # 2005-03-02 fl fixed iterparse support for pre-2.2 versions # # Copyright (c) 1999-2005 by Fredrik Lundh. All rights reserved. # # fredrik@pythonware.com # http://www.pythonware.com # # -------------------------------------------------------------------- # The ElementTree toolkit is # # Copyright (c) 1999-2005 by Fredrik Lundh # # By obtaining, using, and/or copying this software and/or its # associated documentation, you agree that you have read, understood, # and will comply with the following terms and conditions: # # Permission to use, copy, modify, and distribute this software and # its associated documentation for any purpose and without fee is # hereby granted, provided that the above copyright notice appears in # all copies, and that both that copyright notice and this permission # notice appear in supporting documentation, and that the name of # Secret Labs AB or the author not be used in advertising or publicity # pertaining to distribution of the software without specific, written # prior permission. # # SECRET LABS AB AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD # TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANT- # ABILITY AND FITNESS. IN NO EVENT SHALL SECRET LABS AB OR THE AUTHOR # BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY # DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, # WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS # ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE # OF THIS SOFTWARE. # -------------------------------------------------------------------- # Licensed to PSF under a Contributor Agreement. # See http://www.python.org/2.4/license for licensing details. __all__ = [ # public symbols "Comment", "dump", "Element", "ElementTree", "fromstring", "iselement", "iterparse", "parse", "PI", "ProcessingInstruction", "QName", "SubElement", "tostring", "TreeBuilder", "VERSION", "XML", "XMLParser", "XMLTreeBuilder", ] ## # The Element type is a flexible container object, designed to # store hierarchical data structures in memory. The type can be # described as a cross between a list and a dictionary. # # Each element has a number of properties associated with it: # <ul> # <li>a tag. This is a string identifying what kind of data # this element represents (the element type, in other words).</li> # <li>a number of attributes, stored in a Python dictionary.</li> # <li>a text string.</li> # <li>an optional tail string.</li> # <li>a number of child elements, stored in a Python sequence</li> # </ul> # # To create an element instance, use the {@link #Element} or {@link # #SubElement} factory functions. # # The {@link #ElementTree} class can be used to wrap an element # structure, and convert it from and to XML. ## import string, sys, re class _SimpleElementPath: # emulate pre-1.2 find/findtext/findall behaviour def find(self, element, tag): for elem in element: if elem.tag == tag: return elem return None def findtext(self, element, tag, default=None): for elem in element: if elem.tag == tag: return elem.text or "" return default def findall(self, element, tag): if tag[:3] == ".//": return element.getiterator(tag[3:]) result = [] for elem in element: if elem.tag == tag: result.append(elem) return result try: import ElementPath except ImportError: # FIXME: issue warning in this case? ElementPath = _SimpleElementPath() # TODO: add support for custom namespace resolvers/default namespaces # TODO: add improved support for incremental parsing VERSION = "1.2.6" ## # Internal element class. This class defines the Element interface, # and provides a reference implementation of this interface. # # You should not create instances of this class directly. Use the # appropriate factory functions instead, such as {@link #Element} # and {@link #SubElement}. # # @see Element # @see SubElement # @see Comment # @see ProcessingInstruction class _ElementInterface: # <tag attrib>text<child/>...</tag>tail ## # (Attribute) Element tag. tag = None ## # (Attribute) Element attribute dictionary. Where possible, use # {@link #_ElementInterface.get}, # {@link #_ElementInterface.set}, # {@link #_ElementInterface.keys}, and # {@link #_ElementInterface.items} to access # element attributes. attrib = None ## # (Attribute) Text before first subelement. This is either a # string or the value None, if there was no text. text = None ## # (Attribute) Text after this element's end tag, but before the # next sibling element's start tag. This is either a string or # the value None, if there was no text. tail = None # text after end tag, if any def __init__(self, tag, attrib): self.tag = tag self.attrib = attrib self._children = [] def __repr__(self): return "<Element %s at %x>" % (self.tag, id(self)) ## # Creates a new element object of the same type as this element. # # @param tag Element tag. # @param attrib Element attributes, given as a dictionary. # @return A new element instance. def makeelement(self, tag, attrib): return Element(tag, attrib) ## # Returns the number of subelements. # # @return The number of subelements. def __len__(self): return len(self._children) ## # Returns the given subelement. # # @param index What subelement to return. # @return The given subelement. # @exception IndexError If the given element does not exist. def __getitem__(self, index): return self._children[index] ## # Replaces the given subelement. # # @param index What subelement to replace. # @param element The new element value. # @exception IndexError If the given element does not exist. # @exception AssertionError If element is not a valid object. def __setitem__(self, index, element): assert iselement(element) self._children[index] = element ## # Deletes the given subelement. # # @param index What subelement to delete. # @exception IndexError If the given element does not exist. def __delitem__(self, index): del self._children[index] ## # Returns a list containing subelements in the given range. # # @param start The first subelement to return. # @param stop The first subelement that shouldn't be returned. # @return A sequence object containing subelements. def __getslice__(self, start, stop): return self._children[start:stop] ## # Replaces a number of subelements with elements from a sequence. # # @param start The first subelement to replace. # @param stop The first subelement that shouldn't be replaced. # @param elements A sequence object with zero or more elements. # @exception AssertionError If a sequence member is not a valid object. def __setslice__(self, start, stop, elements): for element in elements: assert iselement(element) self._children[start:stop] = list(elements) ## # Deletes a number of subelements. # # @param start The first subelement to delete. # @param stop The first subelement to leave in there. def __delslice__(self, start, stop): del self._children[start:stop] ## # Adds a subelement to the end of this element. # # @param element The element to add. # @exception AssertionError If a sequence member is not a valid object. def append(self, element): assert iselement(element) self._children.append(element) ## # Inserts a subelement at the given position in this element. # # @param index Where to insert the new subelement. # @exception AssertionError If the element is not a valid object. def insert(self, index, element): assert iselement(element) self._children.insert(index, element) ## # Removes a matching subelement. Unlike the find methods, # this method compares elements based on identity, not on tag # value or contents. # # @param element What element to remove. # @exception ValueError If a matching element could not be found. # @exception AssertionError If the element is not a valid object. def remove(self, element): assert iselement(element) self._children.remove(element) ## # Returns all subelements. The elements are returned in document # order. # # @return A list of subelements. # @defreturn list of Element instances def getchildren(self): return self._children ## # Finds the first matching subelement, by tag name or path. # # @param path What element to look for. # @return The first matching element, or None if no element was found. # @defreturn Element or None def find(self, path): return ElementPath.find(self, path) ## # Finds text for the first matching subelement, by tag name or path. # # @param path What element to look for. # @param default What to return if the element was not found. # @return The text content of the first matching element, or the # default value no element was found. Note that if the element # has is found, but has no text content, this method returns an # empty string. # @defreturn string def findtext(self, path, default=None): return ElementPath.findtext(self, path, default) ## # Finds all matching subelements, by tag name or path. # # @param path What element to look for. # @return A list or iterator containing all matching elements, # in document order. # @defreturn list of Element instances def findall(self, path): return ElementPath.findall(self, path) ## # Resets an element. This function removes all subelements, clears # all attributes, and sets the text and tail attributes to None. def clear(self): self.attrib.clear() self._children = [] self.text = self.tail = None ## # Gets an element attribute. # # @param key What attribute to look for. # @param default What to return if the attribute was not found. # @return The attribute value, or the default value, if the # attribute was not found. # @defreturn string or None def get(self, key, default=None): return self.attrib.get(key, default) ## # Sets an element attribute. # # @param key What attribute to set. # @param value The attribute value. def set(self, key, value): self.attrib[key] = value ## # Gets a list of attribute names. The names are returned in an # arbitrary order (just like for an ordinary Python dictionary). # # @return A list of element attribute names. # @defreturn list of strings def keys(self): return self.attrib.keys() ## # Gets element attributes, as a sequence. The attributes are # returned in an arbitrary order. # # @return A list of (name, value) tuples for all attributes. # @defreturn list of (string, string) tuples def items(self): return self.attrib.items() ## # Creates a tree iterator. The iterator loops over this element # and all subelements, in document order, and returns all elements # with a matching tag. # # If the tree structure is modified during iteration, the result # is undefined. # # @param tag What tags to look for (default is to return all elements). # @return A list or iterator containing all the matching elements. # @defreturn list or iterator def getiterator(self, tag=None): nodes = [] if tag == "*": tag = None if tag is None or self.tag == tag: nodes.append(self) for node in self._children: nodes.extend(node.getiterator(tag)) return nodes # compatibility _Element = _ElementInterface ## # Element factory. This function returns an object implementing the # standard Element interface. The exact class or type of that object # is implementation dependent, but it will always be compatible with # the {@link #_ElementInterface} class in this module. # # The element name, attribute names, and attribute values can be # either 8-bit ASCII strings or Unicode strings. # # @param tag The element name. # @param attrib An optional dictionary, containing element attributes. # @param **extra Additional attributes, given as keyword arguments. # @return An element instance. # @defreturn Element def Element(tag, attrib={}, **extra): attrib = attrib.copy() attrib.update(extra) return _ElementInterface(tag, attrib) ## # Subelement factory. This function creates an element instance, and # appends it to an existing element. # # The element name, attribute names, and attribute values can be # either 8-bit ASCII strings or Unicode strings. # # @param parent The parent element. # @param tag The subelement name. # @param attrib An optional dictionary, containing element attributes. # @param **extra Additional attributes, given as keyword arguments. # @return An element instance. # @defreturn Element def SubElement(parent, tag, attrib={}, **extra): attrib = attrib.copy() attrib.update(extra) element = parent.makeelement(tag, attrib) parent.append(element) return element ## # Comment element factory. This factory function creates a special # element that will be serialized as an XML comment. # # The comment string can be either an 8-bit ASCII string or a Unicode # string. # # @param text A string containing the comment string. # @return An element instance, representing a comment. # @defreturn Element def Comment(text=None): element = Element(Comment) element.text = text return element ## # PI element factory. This factory function creates a special element # that will be serialized as an XML processing instruction. # # @param target A string containing the PI target. # @param text A string containing the PI contents, if any. # @return An element instance, representing a PI. # @defreturn Element def ProcessingInstruction(target, text=None): element = Element(ProcessingInstruction) element.text = target if text: element.text = element.text + " " + text return element PI = ProcessingInstruction ## # QName wrapper. This can be used to wrap a QName attribute value, in # order to get proper namespace handling on output. # # @param text A string containing the QName value, in the form {uri}local, # or, if the tag argument is given, the URI part of a QName. # @param tag Optional tag. If given, the first argument is interpreted as # an URI, and this argument is interpreted as a local name. # @return An opaque object, representing the QName. class QName: def __init__(self, text_or_uri, tag=None): if tag: text_or_uri = "{%s}%s" % (text_or_uri, tag) self.text = text_or_uri def __str__(self): return self.text def __hash__(self): return hash(self.text) def __cmp__(self, other): if isinstance(other, QName): return cmp(self.text, other.text) return cmp(self.text, other) ## # ElementTree wrapper class. This class represents an entire element # hierarchy, and adds some extra support for serialization to and from # standard XML. # # @param element Optional root element. # @keyparam file Optional file handle or name. If given, the # tree is initialized with the contents of this XML file. class ElementTree: def __init__(self, element=None, file=None): assert element is None or iselement(element) self._root = element # first node if file: self.parse(file) ## # Gets the root element for this tree. # # @return An element instance. # @defreturn Element def getroot(self): return self._root ## # Replaces the root element for this tree. This discards the # current contents of the tree, and replaces it with the given # element. Use with care. # # @param element An element instance. def _setroot(self, element): assert iselement(element) self._root = element ## # Loads an external XML document into this element tree. # # @param source A file name or file object. # @param parser An optional parser instance. If not given, the # standard {@link XMLTreeBuilder} parser is used. # @return The document root element. # @defreturn Element def parse(self, source, parser=None): if not hasattr(source, "read"): source = open(source, "rb") if not parser: parser = XMLTreeBuilder() while 1: data = source.read(32768) if not data: break parser.feed(data) self._root = parser.close() return self._root ## # Creates a tree iterator for the root element. The iterator loops # over all elements in this tree, in document order. # # @param tag What tags to look for (default is to return all elements) # @return An iterator. # @defreturn iterator def getiterator(self, tag=None): assert self._root is not None return self._root.getiterator(tag) ## # Finds the first toplevel element with given tag. # Same as getroot().find(path). # # @param path What element to look for. # @return The first matching element, or None if no element was found. # @defreturn Element or None def find(self, path): assert self._root is not None if path[:1] == "/": path = "." + path return self._root.find(path) ## # Finds the element text for the first toplevel element with given # tag. Same as getroot().findtext(path). # # @param path What toplevel element to look for. # @param default What to return if the element was not found. # @return The text content of the first matching element, or the # default value no element was found. Note that if the element # has is found, but has no text content, this method returns an # empty string. # @defreturn string def findtext(self, path, default=None): assert self._root is not None if path[:1] == "/": path = "." + path return self._root.findtext(path, default) ## # Finds all toplevel elements with the given tag. # Same as getroot().findall(path). # # @param path What element to look for. # @return A list or iterator containing all matching elements, # in document order. # @defreturn list of Element instances def findall(self, path): assert self._root is not None if path[:1] == "/": path = "." + path return self._root.findall(path) ## # Writes the element tree to a file, as XML. # # @param file A file name, or a file object opened for writing. # @param encoding Optional output encoding (default is US-ASCII). def write(self, file, encoding="us-ascii"): assert self._root is not None if not hasattr(file, "write"): file = open(file, "wb") if not encoding: encoding = "us-ascii" elif encoding != "utf-8" and encoding != "us-ascii": file.write("<?xml version='1.0' encoding='%s'?>\n" % encoding) self._write(file, self._root, encoding, {}) def _write(self, file, node, encoding, namespaces): # write XML to file tag = node.tag if tag is Comment: file.write("" % _escape_cdata(node.text, encoding)) elif tag is ProcessingInstruction: file.write("<?%s?>" % _escape_cdata(node.text, encoding)) else: items = node.items() xmlns_items = [] # new namespaces in this scope try: if isinstance(tag, QName) or tag[:1] == "{": tag, xmlns = fixtag(tag, namespaces) if xmlns: xmlns_items.append(xmlns) except TypeError: _raise_serialization_error(tag) file.write("<" + _encode(tag, encoding)) if items or xmlns_items: items.sort() # lexical order for k, v in items: try: if isinstance(k, QName) or k[:1] == "{": k, xmlns = fixtag(k, namespaces) if xmlns: xmlns_items.append(xmlns) except TypeError: _raise_serialization_error(k) try: if isinstance(v, QName): v, xmlns = fixtag(v, namespaces) if xmlns: xmlns_items.append(xmlns) except TypeError: _raise_serialization_error(v) file.write(" %s=\"%s\"" % (_encode(k, encoding), _escape_attrib(v, encoding))) for k, v in xmlns_items: file.write(" %s=\"%s\"" % (_encode(k, encoding), _escape_attrib(v, encoding))) if node.text or len(node): file.write(">") if node.text: file.write(_escape_cdata(node.text, encoding)) for n in node: self._write(file, n, encoding, namespaces) file.write("</" + _encode(tag, encoding) + ">") else: file.write(" />") for k, v in xmlns_items: del namespaces[v] if node.tail: file.write(_escape_cdata(node.tail, encoding)) # -------------------------------------------------------------------- # helpers ## # Checks if an object appears to be a valid element object. # # @param An element instance. # @return A true value if this is an element object. # @defreturn flag def iselement(element): # FIXME: not sure about this; might be a better idea to look # for tag/attrib/text attributes return isinstance(element, _ElementInterface) or hasattr(element, "tag") ## # Writes an element tree or element structure to sys.stdout. This # function should be used for debugging only. # # The exact output format is implementation dependent. In this # version, it's written as an ordinary XML file. # # @param elem An element tree or an individual element. def dump(elem): # debugging if not isinstance(elem, ElementTree): elem = ElementTree(elem) elem.write(sys.stdout) tail = elem.getroot().tail if not tail or tail[-1] != "\n": sys.stdout.write("\n") def _encode(s, encoding): try: return s.encode(encoding) except AttributeError: return s # 1.5.2: assume the string uses the right encoding if sys.version[:3] == "1.5": _escape = re.compile(r"[&<>\"\x80-\xff]+") # 1.5.2 else: _escape = re.compile(eval(r'u"[&<>\"\u0080-\uffff]+"')) _escape_map = { "&": "&", "<": "<", ">": ">", '"': """, } _namespace_map = { # "well-known" namespace prefixes "http://www.w3.org/XML/1998/namespace": "xml", "http://www.w3.org/1999/xhtml": "html", "http://www.w3.org/1999/02/22-rdf-syntax-ns#": "rdf", "http://schemas.xmlsoap.org/wsdl/": "wsdl", } def _raise_serialization_error(text): raise TypeError( "cannot serialize %r (type %s)" % (text, type(text).__name__) ) def _encode_entity(text, pattern=_escape): # map reserved and non-ascii characters to numerical entities def escape_entities(m, map=_escape_map): out = [] append = out.append for char in m.group(): text = map.get(char) if text is None: text = "&#%d;" % ord(char) append(text) return string.join(out, "") try: return _encode(pattern.sub(escape_entities, text), "ascii") except TypeError: _raise_serialization_error(text) # # the following functions assume an ascii-compatible encoding # (or "utf-16") def _escape_cdata(text, encoding=None, replace=string.replace): # escape character data try: if encoding: try: text = _encode(text, encoding) except UnicodeError: return _encode_entity(text) text = replace(text, "&", "&") text = replace(text, "<", "<") text = replace(text, ">", ">") return text except (TypeError, AttributeError): _raise_serialization_error(text) def _escape_attrib(text, encoding=None, replace=string.replace): # escape attribute value try: if encoding: try: text = _encode(text, encoding) except UnicodeError: return _encode_entity(text) text = replace(text, "&", "&") text = replace(text, "'", "'") # FIXME: overkill text = replace(text, "\"", """) text = replace(text, "<", "<") text = replace(text, ">", ">") return text except (TypeError, AttributeError): _raise_serialization_error(text) def fixtag(tag, namespaces): # given a decorated tag (of the form {uri}tag), return prefixed # tag and namespace declaration, if any if isinstance(tag, QName): tag = tag.text namespace_uri, tag = string.split(tag[1:], "}", 1) prefix = namespaces.get(namespace_uri) if prefix is None: prefix = _namespace_map.get(namespace_uri) if prefix is None: prefix = "ns%d" % len(namespaces) namespaces[namespace_uri] = prefix if prefix == "xml": xmlns = None else: xmlns = ("xmlns:%s" % prefix, namespace_uri) else: xmlns = None return "%s:%s" % (prefix, tag), xmlns ## # Parses an XML document into an element tree. # # @param source A filename or file object containing XML data. # @param parser An optional parser instance. If not given, the # standard {@link XMLTreeBuilder} parser is used. # @return An ElementTree instance def parse(source, parser=None): tree = ElementTree() tree.parse(source, parser) return tree ## # Parses an XML document into an element tree incrementally, and reports # what's going on to the user. # # @param source A filename or file object containing XML data. # @param events A list of events to report back. If omitted, only "end" # events are reported. # @return A (event, elem) iterator. class iterparse: def __init__(self, source, events=None): if not hasattr(source, "read"): source = open(source, "rb") self._file = source self._events = [] self._index = 0 self.root = self._root = None self._parser = XMLTreeBuilder() # wire up the parser for event reporting parser = self._parser._parser append = self._events.append if events is None: events = ["end"] for event in events: if event == "start": try: parser.ordered_attributes = 1 parser.specified_attributes = 1 def handler(tag, attrib_in, event=event, append=append, start=self._parser._start_list): append((event, start(tag, attrib_in))) parser.StartElementHandler = handler except AttributeError: def handler(tag, attrib_in, event=event, append=append, start=self._parser._start): append((event, start(tag, attrib_in))) parser.StartElementHandler = handler elif event == "end": def handler(tag, event=event, append=append, end=self._parser._end): append((event, end(tag))) parser.EndElementHandler = handler elif event == "start-ns": def handler(prefix, uri, event=event, append=append): try: uri = _encode(uri, "ascii") except UnicodeError: pass append((event, (prefix or "", uri))) parser.StartNamespaceDeclHandler = handler elif event == "end-ns": def handler(prefix, event=event, append=append): append((event, None)) parser.EndNamespaceDeclHandler = handler def next(self): while 1: try: item = self._events[self._index] except IndexError: if self._parser is None: self.root = self._root try: raise StopIteration except NameError: raise IndexError # load event buffer del self._events[:] self._index = 0 data = self._file.read(16384) if data: self._parser.feed(data) else: self._root = self._parser.close() self._parser = None else: self._index = self._index + 1 return item try: iter def __iter__(self): return self except NameError: def __getitem__(self, index): return self.next() ## # Parses an XML document from a string constant. This function can # be used to embed "XML literals" in Python code. # # @param source A string containing XML data. # @return An Element instance. # @defreturn Element def XML(text): parser = XMLTreeBuilder() parser.feed(text) return parser.close() ## # Parses an XML document from a string constant, and also returns # a dictionary which maps from element id:s to elements. # # @param source A string containing XML data. # @return A tuple containing an Element instance and a dictionary. # @defreturn (Element, dictionary) def XMLID(text): parser = XMLTreeBuilder() parser.feed(text) tree = parser.close() ids = {} for elem in tree.getiterator(): id = elem.get("id") if id: ids[id] = elem return tree, ids ## # Parses an XML document from a string constant. Same as {@link #XML}. # # @def fromstring(text) # @param source A string containing XML data. # @return An Element instance. # @defreturn Element fromstring = XML ## # Generates a string representation of an XML element, including all # subelements. # # @param element An Element instance. # @return An encoded string containing the XML data. # @defreturn string def tostring(element, encoding=None): class dummy: pass data = [] file = dummy() file.write = data.append ElementTree(element).write(file, encoding) return string.join(data, "") ## # Generic element structure builder. This builder converts a sequence # of {@link #TreeBuilder.start}, {@link #TreeBuilder.data}, and {@link # #TreeBuilder.end} method calls to a well-formed element structure. # # You can use this class to build an element structure using a custom XML # parser, or a parser for some other XML-like format. # # @param element_factory Optional element factory. This factory # is called to create new Element instances, as necessary. class TreeBuilder: def __init__(self, element_factory=None): self._data = [] # data collector self._elem = [] # element stack self._last = None # last element self._tail = None # true if we're after an end tag if element_factory is None: element_factory = _ElementInterface self._factory = element_factory ## # Flushes the parser buffers, and returns the toplevel documen # element. # # @return An Element instance. # @defreturn Element def close(self): assert len(self._elem) == 0, "missing end tags" assert self._last != None, "missing toplevel element" return self._last def _flush(self): if self._data: if self._last is not None: text = string.join(self._data, "") if self._tail: assert self._last.tail is None, "internal error (tail)" self._last.tail = text else: assert self._last.text is None, "internal error (text)" self._last.text = text self._data = [] ## # Adds text to the current element. # # @param data A string. This should be either an 8-bit string # containing ASCII text, or a Unicode string. def data(self, data): self._data.append(data) ## # Opens a new element. # # @param tag The element name. # @param attrib A dictionary containing element attributes. # @return The opened element. # @defreturn Element def start(self, tag, attrs): self._flush() self._last = elem = self._factory(tag, attrs) if self._elem: self._elem[-1].append(elem) self._elem.append(elem) self._tail = 0 return elem ## # Closes the current element. # # @param tag The element name. # @return The closed element. # @defreturn Element def end(self, tag): self._flush() self._last = self._elem.pop() assert self._last.tag == tag,\ "end tag mismatch (expected %s, got %s)" % ( self._last.tag, tag) self._tail = 1 return self._last ## # Element structure builder for XML source data, based on the # expat parser. # # @keyparam target Target object. If omitted, the builder uses an # instance of the standard {@link #TreeBuilder} class. # @keyparam html Predefine HTML entities. This flag is not supported # by the current implementation. # @see #ElementTree # @see #TreeBuilder class XMLTreeBuilder: def __init__(self, html=0, target=None): try: from xml.parsers import expat except ImportError: raise ImportError( "No module named expat; use SimpleXMLTreeBuilder instead" ) self._parser = parser = expat.ParserCreate(None, "}") if target is None: target = TreeBuilder() self._target = target self._names = {} # name memo cache # callbacks parser.DefaultHandlerExpand = self._default parser.StartElementHandler = self._start parser.EndElementHandler = self._end parser.CharacterDataHandler = self._data # let expat do the buffering, if supported try: self._parser.buffer_text = 1 except AttributeError: pass # use new-style attribute handling, if supported try: self._parser.ordered_attributes = 1 self._parser.specified_attributes = 1 parser.StartElementHandler = self._start_list except AttributeError: pass encoding = None if not parser.returns_unicode: encoding = "utf-8" # target.xml(encoding, None) self._doctype = None self.entity = {} def _fixtext(self, text): # convert text string to ascii, if possible try: return _encode(text, "ascii") except UnicodeError: return text def _fixname(self, key): # expand qname, and convert name string to ascii, if possible try: name = self._names[key] except KeyError: name = key if "}" in name: name = "{" + name self._names[key] = name = self._fixtext(name) return name def _start(self, tag, attrib_in): fixname = self._fixname tag = fixname(tag) attrib = {} for key, value in attrib_in.items(): attrib[fixname(key)] = self._fixtext(value) return self._target.start(tag, attrib) def _start_list(self, tag, attrib_in): fixname = self._fixname tag = fixname(tag) attrib = {} if attrib_in: for i in range(0, len(attrib_in), 2): attrib[fixname(attrib_in[i])] = self._fixtext(attrib_in[i+1]) return self._target.start(tag, attrib) def _data(self, text): return self._target.data(self._fixtext(text)) def _end(self, tag): return self._target.end(self._fixname(tag)) def _default(self, text): prefix = text[:1] if prefix == "&": # deal with undefined entities try: self._target.data(self.entity[text[1:-1]]) except KeyError: from xml.parsers import expat raise expat.error( "undefined entity %s: line %d, column %d" % (text, self._parser.ErrorLineNumber, self._parser.ErrorColumnNumber) ) elif prefix == "<" and text[:9] == "<!DOCTYPE": self._doctype = [] # inside a doctype declaration elif self._doctype is not None: # parse doctype contents if prefix == ">": self._doctype = None return text = string.strip(text) if not text: return self._doctype.append(text) n = len(self._doctype) if n > 2: type = self._doctype[1] if type == "PUBLIC" and n == 4: name, type, pubid, system = self._doctype elif type == "SYSTEM" and n == 3: name, type, system = self._doctype pubid = None else: return if pubid: pubid = pubid[1:-1] self.doctype(name, pubid, system[1:-1]) self._doctype = None ## # Handles a doctype declaration. # # @param name Doctype name. # @param pubid Public identifier. # @param system System identifier. def doctype(self, name, pubid, system): pass ## # Feeds data to the parser. # # @param data Encoded data. def feed(self, data): self._parser.Parse(data, 0) ## # Finishes feeding data to the parser. # # @return An element structure. # @defreturn Element def close(self): self._parser.Parse("", 1) # end of data tree = self._target.close() del self._target, self._parser # get rid of circular references return tree # compatibility XMLParser = XMLTreeBuilder