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 """ # 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") listElements, invert = listElementsMap[variant] for node in reversed(self.openElements): if (node.name == target and not exactNode or node == target and exactNode): 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