import sys
import xml.dom
import xml.dom.minidom
import re

# Sanitize SVG by removing any script calls of any sort.  
# Returns a non-zero exit value if any changes were made.
#
# WARNING:
# * Does not validate the SVG against a DTD (or schema or whatever)
# * Pieces of non-SVG XML are mostly not sanitized, but must come from a short list of namespaces.
# * Reformats even documents that need no changes (but leaves the XML semantically identical).
#


class Namespace:
	def __init__(self, name):
		self.name = name


# SVG itself
svg = Namespace("http://www.w3.org/2000/svg")
# This is the complete list of event attributes from http://www.w3.org/TR/SVG/interact.html#SVGEvents
svg.event_attributes = [
	"onfocusin",
	"onfocusout",
	"onactivate",
	"onclick",
	"onmousedown",
	"onmouseup",
	"onmouseover",
	"onmousemove",
	"onmouseout",
	"onload",
	"onunload",
	"onabort",
	"onerror",
	"onresize",
	"onscroll",
	"onzoom",
	"onbegin",
	"onend",
	"onrepeat",
	]

# From http://www.w3.org/TR/SVG/script.html
svg.script_attributes = [ 
	"contentScriptType",
	]
svg.script_tags = [
	"script",
	]

svg.evil_attributes = svg.script_attributes + svg.event_attributes
svg.evil_tags = svg.script_tags



svgns = [
	"http://www.w3.org/2000/svg",
	]
adobens = [
	"http://ns.adobe.com/Extensibility/1.0/",
	"http://ns.adobe.com/Flows/1.0/",
	"http://ns.adobe.com/AdobeIllustrator/10.0/",
	"http://ns.adobe.com/AdobeSVGViewerExtensions/3.0/",
	]
metans = [
	"http://web.resource.org/cc/",
	"http://purl.org/dc/elements/1.1/",
	"http://www.w3.org/1999/02/22-rdf-syntax-ns#",
	"http://www.w3.org/2000/xmlns/",
	"http://www.w3.org/XML/1998/namespace",
	"http://www.w3.org/1999/xlink",
	]
inkns = [
	"http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd",
	"http://inkscape.sourceforge.net/DTD/sodipodi-0.dtd",
	"http://www.inkscape.org/namespaces/inkscape",
	]
msns = [
	"http://schemas.microsoft.com/visio/2003/SVGExtensions/",
	]



acceptable_namespaces = [None] + svgns + adobens + metans + inkns + msns

namespaces = {}
for a in acceptable_namespaces:
	namespaces[a] = None

# Some namespaces get sanitized as if they were SVG
special_namespaces = { None:svg }
for ns in svgns + adobens + inkns + msns:
	special_namespaces[ns] = svg




def message(s):
	sys.stderr.write(s)
	sys.stderr.write("\n")
	sys.stderr.flush()




def element_is_acceptable(node):
	global adobe_extensions
	global ink_extensions
	if node.namespaceURI in adobens: adobe_extensions = True
	if node.namespaceURI in inkns: ink_extensions = True
	if node.namespaceURI not in namespaces:
		message("Namespace '%s'not found; element '%s' unacceptable." % (node.namespaceURI,node))
		return False
	if node.namespaceURI in special_namespaces:
		if node.localName in special_namespaces[node.namespaceURI].evil_tags:
			message("Element '%s' unacceptable." % node)
			return False
	return True

def attribute_is_acceptable(node, attribute):
	nsURI = attribute.namespaceURI or node.namespaceURI
	if nsURI in adobens: adobe_extensions = True
	if nsURI in inkns: ink_extensions = True
	if not nsURI in namespaces:
		message("Namespace '%s'not found; attribute '%s' unacceptable." % (attribute.namespaceURI or node.namespaceURI,node))
		return False
	if nsURI in special_namespaces and attribute.localName in special_namespaces[nsURI].evil_attributes:
		message("Attribute '%s' unacceptable." % attribute)
		return False
	return True




# Begin cleansing
changes = False

doc = xml.dom.minidom.parse(sys.stdin)

# Accept all versions of SVG
if doc.doctype:
	if doc.doctype.name<>"svg" or not re.match(r"-//W3C//DTD SVG [0-9.]+//.*",doc.doctype.publicId):
		raise ValueError, 'Document does not appear to be SVG; doctype is "%s"' % doc.doctype.publicId
else:
	# No doctype definition; accept as SVG anyway
	if not doc.documentElement.namespaceURI in [None,svg.name] or doc.documentElement.localName<>"svg":
		raise ValueError, 'Document does not appear to be SVG; no doctype and root tag is "%s" in namespace "%s".' % (doc.documentElement, doc.documentElement.namespaceURI)

# Generic DOM function
def walk_tree(node):
	yield node
	for n in node.childNodes:
		for t in walk_tree(n):
			yield t


adobe_extensions = False
ink_extensions = False


for node in walk_tree(doc):
	# Eradicate anything from other namespaces
	if not element_is_acceptable(node):
		changes=True
		node.parentNode.removeChild(node)

	# Eradicate evil attributes
	if node.attributes is not None:
		for attr in map(lambda x: node.attributes.item(x), range(node.attributes.length)):
			if not attribute_is_acceptable(node,attr):
				node.removeAttributeNode(attr)
				changes = True

#if adobe_extensions: message("File contains Adobe extensions to SVG.")
#if ink_extensions: message("File contains Inkscape/Sodipodi extensions to SVG.")
sys.stdout.write(doc.toxml("utf-8"))

print #newline at end of file

if changes:
	sys.exit(1)
else:
	sys.exit(0)