Project

General

Profile

1 21 aaronmk
# XML DOM tree manipulation
2
3 73 aaronmk
import cgi
4
from HTMLParser import HTMLParser
5 21 aaronmk
from xml.dom import Node
6 299 aaronmk
import xml.dom.minidom as minidom
7 21 aaronmk
8 73 aaronmk
import strings
9 331 aaronmk
import util
10 73 aaronmk
11 840 aaronmk
##### Escaping input
12
13 73 aaronmk
def escape(str_):
14
    return strings.to_unicode(cgi.escape(str_, True)).encode('ascii',
15
        'xmlcharrefreplace')
16
17
def unescape(str_): return HTMLParser().unescape(str_)
18
19 840 aaronmk
##### IDs
20 455 aaronmk
21 21 aaronmk
def get_id(node): return node.getAttribute('id')
22
23
def set_id(node, id_): node.setAttribute('id', id_)
24
25 840 aaronmk
##### Element node contents
26 455 aaronmk
27 840 aaronmk
def is_elem(node): return node.nodeType == Node.ELEMENT_NODE
28
29 453 aaronmk
def is_completely_empty(node): return node.firstChild == None
30 135 aaronmk
31 301 aaronmk
def has_one_child(node):
32
    return node.firstChild != None and node.firstChild.nextSibling == None
33
34 840 aaronmk
def is_simple(node):
35
    '''Whether every child recursively has no more than one child'''
36
    return (not is_elem(node) or is_completely_empty(node)
37
        or (has_one_child(node) and is_simple(node.firstChild)))
38
39 305 aaronmk
class NodeIter:
40
    def __init__(self, node): self.child = node.firstChild
41
42
    def __iter__(self): return self
43
44
    def curr(self):
45
        if self.child != None: return self.child
46
        raise StopIteration
47
48
    def next(self):
49
        child = self.curr()
50
        self.child = self.child.nextSibling
51
        return child
52
53 840 aaronmk
##### Comments
54 455 aaronmk
55 453 aaronmk
def is_comment(node): return node.nodeType == Node.COMMENT_NODE
56
57
def is_empty(node):
58
    for child in NodeIter(node):
59
        if not is_comment(child): return False
60
    return True
61
62 840 aaronmk
##### Child nodes that are elements
63 455 aaronmk
64 21 aaronmk
class NodeElemIter:
65
    def __init__(self, node): self.child = node.firstChild
66
67
    def __iter__(self): return self
68
69
    def curr(self):
70
        while self.child != None:
71 298 aaronmk
            if is_elem(self.child): return self.child
72 21 aaronmk
            self.child = self.child.nextSibling
73
        raise StopIteration
74
75
    def next(self):
76
        child = self.curr()
77
        self.child = self.child.nextSibling
78
        return child
79
80
def first_elem(node): return NodeElemIter(node).next()
81
82 450 aaronmk
def has_elems(node):
83
    try: first_elem(node); return True
84
    except StopIteration: return False
85
86 21 aaronmk
class NodeElemReverseIter:
87
    def __init__(self, node): self.child = node.lastChild
88
89
    def __iter__(self): return self
90
91
    def curr(self):
92
        while self.child != None:
93 298 aaronmk
            if is_elem(self.child): return self.child
94 21 aaronmk
            self.child = self.child.previousSibling
95
        raise StopIteration
96
97
    def next(self):
98
        child = self.curr()
99
        self.child = self.child.previousSibling
100
        return child
101
102
def last_elem(node): return NodeElemReverseIter(node).next()
103
104 840 aaronmk
##### Parent nodes
105
106 21 aaronmk
class NodeParentIter:
107 999 aaronmk
    '''Does not treat the document object as the root node's parent, since it's
108
    not a true element node'''
109 21 aaronmk
    def __init__(self, node): self.node = node
110
111
    def __iter__(self): return self
112
113
    def curr(self):
114 298 aaronmk
        if self.node != None and is_elem(self.node): return self.node
115 21 aaronmk
        raise StopIteration
116
117
    def next(self):
118
        node = self.curr()
119
        self.node = self.node.parentNode
120
        return node
121
122 999 aaronmk
def parent(node):
123
    '''See NodeParentIter for special treatment of root node'''
124 1016 aaronmk
    try: return NodeParentIter(node).next()
125 999 aaronmk
    except StopIteration: return None
126
127 840 aaronmk
##### Element nodes containing text
128 661 aaronmk
129 298 aaronmk
def is_text_node(node): return node.nodeType == Node.TEXT_NODE
130
131 301 aaronmk
def is_text(node): return has_one_child(node) and is_text_node(node.firstChild)
132 21 aaronmk
133
def value(node):
134 29 aaronmk
    if node.firstChild != None: return node.firstChild.nodeValue
135 21 aaronmk
    else: return node.nodeValue
136
137 143 aaronmk
def set_value(node, value):
138 298 aaronmk
    if is_elem(node): node.appendChild(node.ownerDocument.createTextNode(value))
139 22 aaronmk
    else: node.nodeValue = value
140
141 86 aaronmk
class NodeTextEntryIter:
142
    def __init__(self, node): self.iter_ = NodeElemIter(node)
143
144
    def __iter__(self): return self
145
146
    def curr(self):
147 839 aaronmk
        entry = self.iter_.curr()
148
        if is_text(entry): value_ = value(entry)
149 964 aaronmk
        elif is_empty(entry): value_ = None
150 839 aaronmk
        else:
151
            assert has_one_child(entry) # TODO: convert to an exception
152
            value_ = entry.firstChild
153
        return (entry.tagName, value_)
154 86 aaronmk
155
    def next(self):
156
        entry = self.curr()
157
        self.iter_.next()
158
        return entry
159
160 792 aaronmk
def is_text_node_entry(val): return util.is_str(val[1])
161
162
class TextEntryOnlyIter(util.CheckedIter):
163
    def __init__(self, iterable):
164
        util.CheckedIter.__init__(self, is_text_node_entry, iterable)
165
166 840 aaronmk
##### Modifying/replacing a node
167 455 aaronmk
168 135 aaronmk
def set_child(node, name, value):
169
    '''Note: does not remove any existing child of the same name'''
170
    child = node.ownerDocument.createElement(name)
171 143 aaronmk
    set_value(child, value)
172 135 aaronmk
    node.appendChild(child)
173
174 435 aaronmk
def remove(node): node.parentNode.removeChild(node)
175
176 963 aaronmk
def replace(old, new):
177
    '''@param new Node|None'''
178
    if new == None: old.parentNode.removeChild(old)
179
    else: old.parentNode.replaceChild(new, old) # note order reversed
180 86 aaronmk
181 757 aaronmk
def replace_with_text(node, new):
182 792 aaronmk
    if util.is_str(new): new = node.ownerDocument.createTextNode(new)
183 757 aaronmk
    replace(node, new)
184 86 aaronmk
185 840 aaronmk
##### Searching child nodes
186 455 aaronmk
187 22 aaronmk
def by_tag_name(node, name, last_only=False):
188 135 aaronmk
    '''last_only optimization returns last matching node'''
189 22 aaronmk
    children = []
190 888 aaronmk
    if last_only: iter_ = NodeElemReverseIter(node)
191
    else: iter_ = NodeElemIter(node)
192
    for child in iter_:
193 22 aaronmk
        if child.tagName == name:
194
            children.append(child)
195
            if last_only: break
196
    return children
197 28 aaronmk
198 840 aaronmk
##### XML documents
199 455 aaronmk
200 133 aaronmk
def create_doc(root='_'):
201 303 aaronmk
    return minidom.getDOMImplementation().createDocument(None, root, None)
202 133 aaronmk
203 840 aaronmk
##### Printing XML
204 455 aaronmk
205 304 aaronmk
prettyxml_config = dict(addindent='    ', newl='\n')
206 331 aaronmk
toprettyxml_config = prettyxml_config.copy()
207
util.rename_key(toprettyxml_config, 'addindent', 'indent')
208 304 aaronmk
209 840 aaronmk
##### minidom modifications
210 455 aaronmk
211 299 aaronmk
minidom._write_data = lambda writer, data: writer.write(escape(data))
212 73 aaronmk
213 305 aaronmk
minidom.Node.__iter__ = lambda self: NodeIter(self)
214
215 857 aaronmk
def __Node_str(self):
216 860 aaronmk
    return strings.remove_extra_newl(self.toprettyxml(**toprettyxml_config))
217 796 aaronmk
minidom.Node.__str__ = __Node_str
218
minidom.Node.__repr__ = __Node_str
219
minidom.Element.__repr__ = __Node_str
220 301 aaronmk
221 888 aaronmk
def __Attr_str(self): return self.name+'="'+escape(self.value)+'"'
222
minidom.Attr.__str__ = __Attr_str
223
minidom.Attr.__repr__ = __Attr_str
224
225 315 aaronmk
minidom.Node.pop = lambda self: self.removeChild(self.lastChild)
226
227
def __Node_clear(self):
228
    while not is_empty(self): self.pop()
229
minidom.Node.clear = __Node_clear
230
231 301 aaronmk
def __Element_write_opening(self, writer, indent='', addindent='', newl=''):
232 298 aaronmk
    writer.write(indent+'<'+self.tagName)
233
    for attr_idx in xrange(self.attributes.length):
234 891 aaronmk
        writer.write(' '+str(self.attributes.item(attr_idx)))
235 298 aaronmk
    writer.write('>'+newl)
236 301 aaronmk
minidom.Element.write_opening = __Element_write_opening
237 73 aaronmk
238 301 aaronmk
def __Element_write_closing(self, writer, indent='', addindent='', newl=''):
239 298 aaronmk
    writer.write('</'+self.tagName+'>'+newl)
240 301 aaronmk
minidom.Element.write_closing = __Element_write_closing
241 298 aaronmk
242 299 aaronmk
_writexml_orig = minidom.Element.writexml
243 301 aaronmk
def __Element_writexml(self, writer, indent='', addindent='', newl=''):
244 306 aaronmk
    if isinstance(indent, int): indent = addindent*indent
245 774 aaronmk
    if is_simple(self):
246
        writer.write(indent)
247
        _writexml_orig(self, writer)
248
        writer.write(newl)
249 28 aaronmk
    else: _writexml_orig(self, writer, indent, addindent, newl)
250 301 aaronmk
minidom.Element.writexml = __Element_writexml
251 28 aaronmk
252 301 aaronmk
def __Document_write_opening(self, writer, indent='', addindent='', newl='',
253
    encoding=None):
254
    xmlDecl = '<?xml version="1.0" '
255
    if encoding != None: xmlDecl += 'encoding="'+escape(encoding)+'"'
256
    xmlDecl += '?>'+newl
257
    writer.write(xmlDecl)
258
    assert has_one_child(self)
259
    assert is_elem(self.firstChild)
260
    self.firstChild.write_opening(writer, indent, addindent, newl)
261
minidom.Document.write_opening = __Document_write_opening
262
263
def __Document_write_closing(self, writer, indent='', addindent='', newl=''):
264
    self.firstChild.write_closing(writer, indent, addindent, newl)
265
minidom.Document.write_closing = __Document_write_closing