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from __future__ import absolute_import, division, unicode_literals
from six import text_type
from ..constants import scopingElements, tableInsertModeElements, namespaces
# The scope markers are inserted when entering object elements,
# marquees, table cells, and table captions, and are used to prevent formatting
# from "leaking" into tables, object elements, and marquees.
Marker = None
listElementsMap = {
None: (frozenset(scopingElements), False),
"button": (frozenset(scopingElements | set([(namespaces["html"], "button")])), False),
"list": (frozenset(scopingElements | set([(namespaces["html"], "ol"),
(namespaces["html"], "ul")])), False),
"table": (frozenset([(namespaces["html"], "html"),
(namespaces["html"], "table")]), False),
"select": (frozenset([(namespaces["html"], "optgroup"),
(namespaces["html"], "option")]), True)
}
class Node(object):
def __init__(self, name):
"""Node representing an item in the tree.
name - The tag name associated with the node
parent - The parent of the current node (or None for the document node)
value - The value of the current node (applies to text nodes and
comments
attributes - a dict holding name, value pairs for attributes of the node
childNodes - a list of child nodes of the current node. This must
include all elements but not necessarily other node types
_flags - A list of miscellaneous flags that can be set on the node
"""
self.name = name
self.parent = None
self.value = None
self.attributes = {}
self.childNodes = []
self._flags = []
def __str__(self):
attributesStr = " ".join(["%s=\"%s\"" % (name, value)
for name, value in
self.attributes.items()])
if attributesStr:
return "<%s %s>" % (self.name, attributesStr)
else:
return "<%s>" % (self.name)
def __repr__(self):
return "<%s>" % (self.name)
def appendChild(self, node):
"""Insert node as a child of the current node
"""
raise NotImplementedError
def insertText(self, data, insertBefore=None):
"""Insert data as text in the current node, positioned before the
start of node insertBefore or to the end of the node's text.
"""
raise NotImplementedError
def insertBefore(self, node, refNode):
"""Insert node as a child of the current node, before refNode in the
list of child nodes. Raises ValueError if refNode is not a child of
the current node"""
raise NotImplementedError
def removeChild(self, node):
"""Remove node from the children of the current node
"""
raise NotImplementedError
def reparentChildren(self, newParent):
"""Move all the children of the current node to newParent.
This is needed so that trees that don't store text as nodes move the
text in the correct way
"""
# XXX - should this method be made more general?
for child in self.childNodes:
newParent.appendChild(child)
self.childNodes = []
def cloneNode(self):
"""Return a shallow copy of the current node i.e. a node with the same
name and attributes but with no parent or child nodes
"""
raise NotImplementedError
def hasContent(self):
"""Return true if the node has children or text, false otherwise
"""
raise NotImplementedError
class ActiveFormattingElements(list):
def append(self, node):
equalCount = 0
if node != Marker:
for element in self[::-1]:
if element == Marker:
break
if self.nodesEqual(element, node):
equalCount += 1
if equalCount == 3:
self.remove(element)
break
list.append(self, node)
def nodesEqual(self, node1, node2):
if not node1.nameTuple == node2.nameTuple:
return False
if not node1.attributes == node2.attributes:
return False
return True
class TreeBuilder(object):
"""Base treebuilder implementation
documentClass - the class to use for the bottommost node of a document
elementClass - the class to use for HTML Elements
commentClass - the class to use for comments
doctypeClass - the class to use for doctypes
"""
# pylint:disable=not-callable
# Document class
documentClass = None
# The class to use for creating a node
elementClass = None
# The class to use for creating comments
commentClass = None
# The class to use for creating doctypes
doctypeClass = None
# Fragment class
fragmentClass = None
def __init__(self, namespaceHTMLElements):
if namespaceHTMLElements:
self.defaultNamespace = "http://www.w3.org/1999/xhtml"
else:
self.defaultNamespace = None
self.reset()
def reset(self):
self.openElements = []
self.activeFormattingElements = ActiveFormattingElements()
# XXX - rename these to headElement, formElement
self.headPointer = None
self.formPointer = None
self.insertFromTable = False
self.document = self.documentClass()
def elementInScope(self, target, variant=None):
# If we pass a node in we match that. if we pass a string
# match any node with that name
exactNode = hasattr(target, "nameTuple")
if not exactNode:
if isinstance(target, text_type):
target = (namespaces["html"], target)
assert isinstance(target, tuple)
listElements, invert = listElementsMap[variant]
for node in reversed(self.openElements):
if exactNode and node == target:
return True
elif not exactNode and node.nameTuple == target:
return True
elif (invert ^ (node.nameTuple in listElements)):
return False
assert False # We should never reach this point
def reconstructActiveFormattingElements(self):
# Within this algorithm the order of steps described in the
# specification is not quite the same as the order of steps in the
# code. It should still do the same though.
# Step 1: stop the algorithm when there's nothing to do.
if not self.activeFormattingElements:
return
# Step 2 and step 3: we start with the last element. So i is -1.
i = len(self.activeFormattingElements) - 1
entry = self.activeFormattingElements[i]
if entry == Marker or entry in self.openElements:
return
# Step 6
while entry != Marker and entry not in self.openElements:
if i == 0:
# This will be reset to 0 below
i = -1
break
i -= 1
# Step 5: let entry be one earlier in the list.
entry = self.activeFormattingElements[i]
while True:
# Step 7
i += 1
# Step 8
entry = self.activeFormattingElements[i]
clone = entry.cloneNode() # Mainly to get a new copy of the attributes
# Step 9
element = self.insertElement({"type": "StartTag",
"name": clone.name,
"namespace": clone.namespace,
"data": clone.attributes})
# Step 10
self.activeFormattingElements[i] = element
# Step 11
if element == self.activeFormattingElements[-1]:
break
def clearActiveFormattingElements(self):
entry = self.activeFormattingElements.pop()
while self.activeFormattingElements and entry != Marker:
entry = self.activeFormattingElements.pop()
def elementInActiveFormattingElements(self, name):
"""Check if an element exists between the end of the active
formatting elements and the last marker. If it does, return it, else
return false"""
for item in self.activeFormattingElements[::-1]:
# Check for Marker first because if it's a Marker it doesn't have a
# name attribute.
if item == Marker:
break
elif item.name == name:
return item
return False
def insertRoot(self, token):
element = self.createElement(token)
self.openElements.append(element)
self.document.appendChild(element)
def insertDoctype(self, token):
name = token["name"]
publicId = token["publicId"]
systemId = token["systemId"]
doctype = self.doctypeClass(name, publicId, systemId)
self.document.appendChild(doctype)
def insertComment(self, token, parent=None):
if parent is None:
parent = self.openElements[-1]
parent.appendChild(self.commentClass(token["data"]))
def createElement(self, token):
"""Create an element but don't insert it anywhere"""
name = token["name"]
namespace = token.get("namespace", self.defaultNamespace)
element = self.elementClass(name, namespace)
element.attributes = token["data"]
return element
def _getInsertFromTable(self):
return self._insertFromTable
def _setInsertFromTable(self, value):
"""Switch the function used to insert an element from the
normal one to the misnested table one and back again"""
self._insertFromTable = value
if value:
self.insertElement = self.insertElementTable
else:
self.insertElement = self.insertElementNormal
insertFromTable = property(_getInsertFromTable, _setInsertFromTable)
def insertElementNormal(self, token):
name = token["name"]
assert isinstance(name, text_type), "Element %s not unicode" % name
namespace = token.get("namespace", self.defaultNamespace)
element = self.elementClass(name, namespace)
element.attributes = token["data"]
self.openElements[-1].appendChild(element)
self.openElements.append(element)
return element
def insertElementTable(self, token):
"""Create an element and insert it into the tree"""
element = self.createElement(token)
if self.openElements[-1].name not in tableInsertModeElements:
return self.insertElementNormal(token)
else:
# We should be in the InTable mode. This means we want to do
# special magic element rearranging
parent, insertBefore = self.getTableMisnestedNodePosition()
if insertBefore is None:
parent.appendChild(element)
else:
parent.insertBefore(element, insertBefore)
self.openElements.append(element)
return element
def insertText(self, data, parent=None):
"""Insert text data."""
if parent is None:
parent = self.openElements[-1]
if (not self.insertFromTable or (self.insertFromTable and
self.openElements[-1].name
not in tableInsertModeElements)):
parent.insertText(data)
else:
# We should be in the InTable mode. This means we want to do
# special magic element rearranging
parent, insertBefore = self.getTableMisnestedNodePosition()
parent.insertText(data, insertBefore)
def getTableMisnestedNodePosition(self):
"""Get the foster parent element, and sibling to insert before
(or None) when inserting a misnested table node"""
# The foster parent element is the one which comes before the most
# recently opened table element
# XXX - this is really inelegant
lastTable = None
fosterParent = None
insertBefore = None
for elm in self.openElements[::-1]:
if elm.name == "table":
lastTable = elm
break
if lastTable:
# XXX - we should really check that this parent is actually a
# node here
if lastTable.parent:
fosterParent = lastTable.parent
insertBefore = lastTable
else:
fosterParent = self.openElements[
self.openElements.index(lastTable) - 1]
else:
fosterParent = self.openElements[0]
return fosterParent, insertBefore
def generateImpliedEndTags(self, exclude=None):
name = self.openElements[-1].name
# XXX td, th and tr are not actually needed
if (name in frozenset(("dd", "dt", "li", "option", "optgroup", "p", "rp", "rt")) and
name != exclude):
self.openElements.pop()
# XXX This is not entirely what the specification says. We should
# investigate it more closely.
self.generateImpliedEndTags(exclude)
def getDocument(self):
"Return the final tree"
return self.document
def getFragment(self):
"Return the final fragment"
# assert self.innerHTML
fragment = self.fragmentClass()
self.openElements[0].reparentChildren(fragment)
return fragment
def testSerializer(self, node):
"""Serialize the subtree of node in the format required by unit tests
node - the node from which to start serializing"""
raise NotImplementedError