/
_base.py
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/
_base.py
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from __future__ import absolute_import, division, unicode_literals
from six import text_type, string_types
__all__ = ["DOCUMENT", "DOCTYPE", "TEXT", "ELEMENT", "COMMENT", "ENTITY", "UNKNOWN",
"TreeWalker", "NonRecursiveTreeWalker"]
from xml.dom import Node
DOCUMENT = Node.DOCUMENT_NODE
DOCTYPE = Node.DOCUMENT_TYPE_NODE
TEXT = Node.TEXT_NODE
ELEMENT = Node.ELEMENT_NODE
COMMENT = Node.COMMENT_NODE
ENTITY = Node.ENTITY_NODE
UNKNOWN = "<#UNKNOWN#>"
from ..constants import voidElements, spaceCharacters
spaceCharacters = "".join(spaceCharacters)
def to_text(s, blank_if_none=True):
"""Wrapper around six.text_type to convert None to empty string"""
if s is None:
if blank_if_none:
return ""
else:
return None
elif isinstance(s, text_type):
return s
else:
return text_type(s)
def is_text_or_none(string):
"""Wrapper around isinstance(string_types) or is None"""
return string is None or isinstance(string, string_types)
class TreeWalker(object):
def __init__(self, tree):
self.tree = tree
def __iter__(self):
raise NotImplementedError
def error(self, msg):
return {"type": "SerializeError", "data": msg}
def emptyTag(self, namespace, name, attrs, hasChildren=False):
assert namespace is None or isinstance(namespace, string_types), type(namespace)
assert isinstance(name, string_types), type(name)
assert all((namespace is None or isinstance(namespace, string_types)) and
isinstance(name, string_types) and
isinstance(value, string_types)
for (namespace, name), value in attrs.items())
yield {"type": "EmptyTag", "name": to_text(name, False),
"namespace": to_text(namespace),
"data": attrs}
if hasChildren:
yield self.error("Void element has children")
def startTag(self, namespace, name, attrs):
assert namespace is None or isinstance(namespace, string_types), type(namespace)
assert isinstance(name, string_types), type(name)
assert all((namespace is None or isinstance(namespace, string_types)) and
isinstance(name, string_types) and
isinstance(value, string_types)
for (namespace, name), value in attrs.items())
return {"type": "StartTag",
"name": text_type(name),
"namespace": to_text(namespace),
"data": dict(((to_text(namespace, False), to_text(name)),
to_text(value, False))
for (namespace, name), value in attrs.items())}
def endTag(self, namespace, name):
assert namespace is None or isinstance(namespace, string_types), type(namespace)
assert isinstance(name, string_types), type(namespace)
return {"type": "EndTag",
"name": to_text(name, False),
"namespace": to_text(namespace),
"data": {}}
def text(self, data):
assert isinstance(data, string_types), type(data)
data = to_text(data)
middle = data.lstrip(spaceCharacters)
left = data[:len(data) - len(middle)]
if left:
yield {"type": "SpaceCharacters", "data": left}
data = middle
middle = data.rstrip(spaceCharacters)
right = data[len(middle):]
if middle:
yield {"type": "Characters", "data": middle}
if right:
yield {"type": "SpaceCharacters", "data": right}
def comment(self, data):
assert isinstance(data, string_types), type(data)
return {"type": "Comment", "data": text_type(data)}
def doctype(self, name, publicId=None, systemId=None, correct=True):
assert is_text_or_none(name), type(name)
assert is_text_or_none(publicId), type(publicId)
assert is_text_or_none(systemId), type(systemId)
return {"type": "Doctype",
"name": to_text(name),
"publicId": to_text(publicId),
"systemId": to_text(systemId),
"correct": to_text(correct)}
def entity(self, name):
assert isinstance(name, string_types), type(name)
return {"type": "Entity", "name": text_type(name)}
def unknown(self, nodeType):
return self.error("Unknown node type: " + nodeType)
class NonRecursiveTreeWalker(TreeWalker):
def getNodeDetails(self, node):
raise NotImplementedError
def getFirstChild(self, node):
raise NotImplementedError
def getNextSibling(self, node):
raise NotImplementedError
def getParentNode(self, node):
raise NotImplementedError
def __iter__(self):
currentNode = self.tree
while currentNode is not None:
details = self.getNodeDetails(currentNode)
type, details = details[0], details[1:]
hasChildren = False
if type == DOCTYPE:
yield self.doctype(*details)
elif type == TEXT:
for token in self.text(*details):
yield token
elif type == ELEMENT:
namespace, name, attributes, hasChildren = details
if name in voidElements:
for token in self.emptyTag(namespace, name, attributes,
hasChildren):
yield token
hasChildren = False
else:
yield self.startTag(namespace, name, attributes)
elif type == COMMENT:
yield self.comment(details[0])
elif type == ENTITY:
yield self.entity(details[0])
elif type == DOCUMENT:
hasChildren = True
else:
yield self.unknown(details[0])
if hasChildren:
firstChild = self.getFirstChild(currentNode)
else:
firstChild = None
if firstChild is not None:
currentNode = firstChild
else:
while currentNode is not None:
details = self.getNodeDetails(currentNode)
type, details = details[0], details[1:]
if type == ELEMENT:
namespace, name, attributes, hasChildren = details
if name not in voidElements:
yield self.endTag(namespace, name)
if self.tree is currentNode:
currentNode = None
break
nextSibling = self.getNextSibling(currentNode)
if nextSibling is not None:
currentNode = nextSibling
break
else:
currentNode = self.getParentNode(currentNode)