Viewing file:  etree_lxml.py (14.42 KB) -rw-r--r--
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"""Module for supporting the lxml.etree library. The idea here is to use as much
of the native library as possible, without using fragile hacks like custom element
names that break between releases. The downside of this is that we cannot represent
all possible trees; specifically the following are known to cause problems:
Text or comments as siblings of the root element
Docypes with no name
When any of these things occur, we emit a DataLossWarning
"""
from __future__ import absolute_import, division, unicode_literals
# pylint:disable=protected-access
import warnings
import re
import sys
try:
from collections.abc import MutableMapping
except ImportError:
from collections import MutableMapping
from . import base
from ..constants import DataLossWarning
from .. import constants
from . import etree as etree_builders
from .. import _ihatexml
import lxml.etree as etree
from pip._vendor.six import PY3, binary_type
fullTree = True
tag_regexp = re.compile("{([^}]*)}(.*)")
comment_type = etree.Comment("asd").tag
class DocumentType(object):
def __init__(self, name, publicId, systemId):
self.name = name
self.publicId = publicId
self.systemId = systemId
class Document(object):
def __init__(self):
self._elementTree = None
self._childNodes = []
def appendChild(self, element):
last = self._elementTree.getroot()
for last in self._elementTree.getroot().itersiblings():
pass
last.addnext(element._element)
def _getChildNodes(self):
return self._childNodes
childNodes = property(_getChildNodes)
def testSerializer(element):
rv = []
infosetFilter = _ihatexml.InfosetFilter(preventDoubleDashComments=True)
def serializeElement(element, indent=0):
if not hasattr(element, "tag"):
if hasattr(element, "getroot"):
# Full tree case
rv.append("#document")
if element.docinfo.internalDTD:
if not (element.docinfo.public_id or
element.docinfo.system_url):
dtd_str = "<!DOCTYPE %s>" % element.docinfo.root_name
else:
dtd_str = """<!DOCTYPE %s "%s" "%s">""" % (
element.docinfo.root_name,
element.docinfo.public_id,
element.docinfo.system_url)
rv.append("|%s%s" % (' ' * (indent + 2), dtd_str))
next_element = element.getroot()
while next_element.getprevious() is not None:
next_element = next_element.getprevious()
while next_element is not None:
serializeElement(next_element, indent + 2)
next_element = next_element.getnext()
elif isinstance(element, str) or isinstance(element, bytes):
# Text in a fragment
assert isinstance(element, str) or sys.version_info[0] == 2
rv.append("|%s\"%s\"" % (' ' * indent, element))
else:
# Fragment case
rv.append("#document-fragment")
for next_element in element:
serializeElement(next_element, indent + 2)
elif element.tag == comment_type:
rv.append("|%s<!-- %s -->" % (' ' * indent, element.text))
if hasattr(element, "tail") and element.tail:
rv.append("|%s\"%s\"" % (' ' * indent, element.tail))
else:
assert isinstance(element, etree._Element)
nsmatch = etree_builders.tag_regexp.match(element.tag)
if nsmatch is not None:
ns = nsmatch.group(1)
tag = nsmatch.group(2)
prefix = constants.prefixes[ns]
rv.append("|%s<%s %s>" % (' ' * indent, prefix,
infosetFilter.fromXmlName(tag)))
else:
rv.append("|%s<%s>" % (' ' * indent,
infosetFilter.fromXmlName(element.tag)))
if hasattr(element, "attrib"):
attributes = []
for name, value in element.attrib.items():
nsmatch = tag_regexp.match(name)
if nsmatch is not None:
ns, name = nsmatch.groups()
name = infosetFilter.fromXmlName(name)
prefix = constants.prefixes[ns]
attr_string = "%s %s" % (prefix, name)
else:
attr_string = infosetFilter.fromXmlName(name)
attributes.append((attr_string, value))
for name, value in sorted(attributes):
rv.append('|%s%s="%s"' % (' ' * (indent + 2), name, value))
if element.text:
rv.append("|%s\"%s\"" % (' ' * (indent + 2), element.text))
indent += 2
for child in element:
serializeElement(child, indent)
if hasattr(element, "tail") and element.tail:
rv.append("|%s\"%s\"" % (' ' * (indent - 2), element.tail))
serializeElement(element, 0)
return "\n".join(rv)
def tostring(element):
"""Serialize an element and its child nodes to a string"""
rv = []
def serializeElement(element):
if not hasattr(element, "tag"):
if element.docinfo.internalDTD:
if element.docinfo.doctype:
dtd_str = element.docinfo.doctype
else:
dtd_str = "<!DOCTYPE %s>" % element.docinfo.root_name
rv.append(dtd_str)
serializeElement(element.getroot())
elif element.tag == comment_type:
rv.append("<!--%s-->" % (element.text,))
else:
# This is assumed to be an ordinary element
if not element.attrib:
rv.append("<%s>" % (element.tag,))
else:
attr = " ".join(["%s=\"%s\"" % (name, value)
for name, value in element.attrib.items()])
rv.append("<%s %s>" % (element.tag, attr))
if element.text:
rv.append(element.text)
for child in element:
serializeElement(child)
rv.append("</%s>" % (element.tag,))
if hasattr(element, "tail") and element.tail:
rv.append(element.tail)
serializeElement(element)
return "".join(rv)
class TreeBuilder(base.TreeBuilder):
documentClass = Document
doctypeClass = DocumentType
elementClass = None
commentClass = None
fragmentClass = Document
implementation = etree
def __init__(self, namespaceHTMLElements, fullTree=False):
builder = etree_builders.getETreeModule(etree, fullTree=fullTree)
infosetFilter = self.infosetFilter = _ihatexml.InfosetFilter(preventDoubleDashComments=True)
self.namespaceHTMLElements = namespaceHTMLElements
class Attributes(MutableMapping):
def __init__(self, element):
self._element = element
def _coerceKey(self, key):
if isinstance(key, tuple):
name = "{%s}%s" % (key[2], infosetFilter.coerceAttribute(key[1]))
else:
name = infosetFilter.coerceAttribute(key)
return name
def __getitem__(self, key):
value = self._element._element.attrib[self._coerceKey(key)]
if not PY3 and isinstance(value, binary_type):
value = value.decode("ascii")
return value
def __setitem__(self, key, value):
self._element._element.attrib[self._coerceKey(key)] = value
def __delitem__(self, key):
del self._element._element.attrib[self._coerceKey(key)]
def __iter__(self):
return iter(self._element._element.attrib)
def __len__(self):
return len(self._element._element.attrib)
def clear(self):
return self._element._element.attrib.clear()
class Element(builder.Element):
def __init__(self, name, namespace):
name = infosetFilter.coerceElement(name)
builder.Element.__init__(self, name, namespace=namespace)
self._attributes = Attributes(self)
def _setName(self, name):
self._name = infosetFilter.coerceElement(name)
self._element.tag = self._getETreeTag(
self._name, self._namespace)
def _getName(self):
return infosetFilter.fromXmlName(self._name)
name = property(_getName, _setName)
def _getAttributes(self):
return self._attributes
def _setAttributes(self, value):
attributes = self.attributes
attributes.clear()
attributes.update(value)
attributes = property(_getAttributes, _setAttributes)
def insertText(self, data, insertBefore=None):
data = infosetFilter.coerceCharacters(data)
builder.Element.insertText(self, data, insertBefore)
def cloneNode(self):
element = type(self)(self.name, self.namespace)
if self._element.attrib:
element._element.attrib.update(self._element.attrib)
return element
class Comment(builder.Comment):
def __init__(self, data):
data = infosetFilter.coerceComment(data)
builder.Comment.__init__(self, data)
def _setData(self, data):
data = infosetFilter.coerceComment(data)
self._element.text = data
def _getData(self):
return self._element.text
data = property(_getData, _setData)
self.elementClass = Element
self.commentClass = Comment
# self.fragmentClass = builder.DocumentFragment
base.TreeBuilder.__init__(self, namespaceHTMLElements)
def reset(self):
base.TreeBuilder.reset(self)
self.insertComment = self.insertCommentInitial
self.initial_comments = []
self.doctype = None
def testSerializer(self, element):
return testSerializer(element)
def getDocument(self):
if fullTree:
return self.document._elementTree
else:
return self.document._elementTree.getroot()
def getFragment(self):
fragment = []
element = self.openElements[0]._element
if element.text:
fragment.append(element.text)
fragment.extend(list(element))
if element.tail:
fragment.append(element.tail)
return fragment
def insertDoctype(self, token):
name = token["name"]
publicId = token["publicId"]
systemId = token["systemId"]
if not name:
warnings.warn("lxml cannot represent empty doctype", DataLossWarning)
self.doctype = None
else:
coercedName = self.infosetFilter.coerceElement(name)
if coercedName != name:
warnings.warn("lxml cannot represent non-xml doctype", DataLossWarning)
doctype = self.doctypeClass(coercedName, publicId, systemId)
self.doctype = doctype
def insertCommentInitial(self, data, parent=None):
assert parent is None or parent is self.document
assert self.document._elementTree is None
self.initial_comments.append(data)
def insertCommentMain(self, data, parent=None):
if (parent == self.document and
self.document._elementTree.getroot()[-1].tag == comment_type):
warnings.warn("lxml cannot represent adjacent comments beyond the root elements", DataLossWarning)
super(TreeBuilder, self).insertComment(data, parent)
def insertRoot(self, token):
# Because of the way libxml2 works, it doesn't seem to be possible to
# alter information like the doctype after the tree has been parsed.
# Therefore we need to use the built-in parser to create our initial
# tree, after which we can add elements like normal
docStr = ""
if self.doctype:
assert self.doctype.name
docStr += "<!DOCTYPE %s" % self.doctype.name
if (self.doctype.publicId is not None or
self.doctype.systemId is not None):
docStr += (' PUBLIC "%s" ' %
(self.infosetFilter.coercePubid(self.doctype.publicId or "")))
if self.doctype.systemId:
sysid = self.doctype.systemId
if sysid.find("'") >= 0 and sysid.find('"') >= 0:
warnings.warn("DOCTYPE system cannot contain single and double quotes", DataLossWarning)
sysid = sysid.replace("'", 'U00027')
if sysid.find("'") >= 0:
docStr += '"%s"' % sysid
else:
docStr += "'%s'" % sysid
else:
docStr += "''"
docStr += ">"
if self.doctype.name != token["name"]:
warnings.warn("lxml cannot represent doctype with a different name to the root element", DataLossWarning)
docStr += "<THIS_SHOULD_NEVER_APPEAR_PUBLICLY/>"
root = etree.fromstring(docStr)
# Append the initial comments:
for comment_token in self.initial_comments:
comment = self.commentClass(comment_token["data"])
root.addprevious(comment._element)
# Create the root document and add the ElementTree to it
self.document = self.documentClass()
self.document._elementTree = root.getroottree()
# Give the root element the right name
name = token["name"]
namespace = token.get("namespace", self.defaultNamespace)
if namespace is None:
etree_tag = name
else:
etree_tag = "{%s}%s" % (namespace, name)
root.tag = etree_tag
# Add the root element to the internal child/open data structures
root_element = self.elementClass(name, namespace)
root_element._element = root
self.document._childNodes.append(root_element)
self.openElements.append(root_element)
# Reset to the default insert comment function
self.insertComment = self.insertCommentMain
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