from __future__ import absolute_import, division, unicode_literals
from xml.dom import Node
from ..constants import namespaces, voidElements, spaceCharacters
__all__ = ["DOCUMENT", "DOCTYPE", "TEXT", "ELEMENT", "COMMENT", "ENTITY", "UNKNOWN",
"TreeWalker", "NonRecursiveTreeWalker"]
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#>"
spaceCharacters = "".join(spaceCharacters)
class TreeWalker(object):
"""Walks a tree yielding tokens
Tokens are dicts that all have a ``type`` field specifying the type of the
token.
"""
def __init__(self, tree):
"""Creates a TreeWalker
:arg tree: the tree to walk
"""
self.tree = tree
def __iter__(self):
raise NotImplementedError
def error(self, msg):
"""Generates an error token with the given message
:arg msg: the error message
:returns: SerializeError token
"""
return {"type": "SerializeError", "data": msg}
def emptyTag(self, namespace, name, attrs, hasChildren=False):
"""Generates an EmptyTag token
:arg namespace: the namespace of the token--can be ``None``
:arg name: the name of the element
:arg attrs: the attributes of the element as a dict
:arg hasChildren: whether or not to yield a SerializationError because
this tag shouldn't have children
:returns: EmptyTag token
"""
yield {"type": "EmptyTag", "name": name,
"namespace": namespace,
"data": attrs}
if hasChildren:
yield self.error("Void element has children")
def startTag(self, namespace, name, attrs):
"""Generates a StartTag token
:arg namespace: the namespace of the token--can be ``None``
:arg name: the name of the element
:arg attrs: the attributes of the element as a dict
:returns: StartTag token
"""
return {"type": "StartTag",
"name": name,
"namespace": namespace,
"data": attrs}
def endTag(self, namespace, name):
"""Generates an EndTag token
:arg namespace: the namespace of the token--can be ``None``
:arg name: the name of the element
:returns: EndTag token
"""
return {"type": "EndTag",
"name": name,
"namespace": namespace}
def text(self, data):
"""Generates SpaceCharacters and Characters tokens
Depending on what's in the data, this generates one or more
``SpaceCharacters`` and ``Characters`` tokens.
For example:
>>> from html5lib.treewalkers.base import TreeWalker
>>> # Give it an empty tree just so it instantiates
>>> walker = TreeWalker([])
>>> list(walker.text(''))
[]
>>> list(walker.text(' '))
[{u'data': ' ', u'type': u'SpaceCharacters'}]
>>> list(walker.text(' abc ')) # doctest: +NORMALIZE_WHITESPACE
[{u'data': ' ', u'type': u'SpaceCharacters'},
{u'data': u'abc', u'type': u'Characters'},
{u'data': u' ', u'type': u'SpaceCharacters'}]
:arg data: the text data
:returns: one or more ``SpaceCharacters`` and ``Characters`` tokens
"""
data = 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):
"""Generates a Comment token
:arg data: the comment
:returns: Comment token
"""
return {"type": "Comment", "data": data}
def doctype(self, name, publicId=None, systemId=None):
"""Generates a Doctype token
:arg name:
:arg publicId:
:arg systemId:
:returns: the Doctype token
"""
return {"type": "Doctype",
"name": name,
"publicId": publicId,
"systemId": systemId}
def entity(self, name):
"""Generates an Entity token
:arg name: the entity name
:returns: an Entity token
"""
return {"type": "Entity", "name": name}
def unknown(self, nodeType):
"""Handles unknown node types"""
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 (not namespace or namespace == namespaces["html"]) and 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 (namespace and namespace != namespaces["html"]) or 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)
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