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